Patent Application
20130217590
The present invention relates to a method for determining a prognosis for survival or the progression of the disease for a patient with leukaemia, the risk of resistance to treatment, or the risk of a relapse of leukaemia, like an acute myeloid leukaemia, e.g. an acute myeloid leukaemia with normal karyotype or a CBF (Core-Binding-Factor) acute myeloid leukaemia, and a method for monitoring the effectiveness of a course of treatment for a patient with leukaemia, as well as a kit for use in said methods, preferably, by quantifying RINF mRNA expression.
Identification of genes specifically deregulated in tumour cells could bring to light new tumour suppressors and oncogenes with potential clinical applications in diagnostics, prognostics, and therapeutics. In PCT application WO 2009/151337 a new target gene of retinoids, CXXC5, encoding a nuclear factor has been described that was functionally characterized for the first time at the mRNA and protein level and named RINF (Retinoid-Inducible Nuclear Factor). In PCT application WO 2010/085153 it is described for the first time that measurement of RINF mRNA in breast cancer tumours, could be informative for overall survival of breast cancer patients.
Present data indicate that RINF plays an essential role during in vitro human hematopoiesis. Indeed, expression studies and gene silencing experiments both demonstrate RINF implication during terminal differentiation of myeloid leukaemia cells (NB4 and HL60 cell lines), but also during myelopoiesis of normal hematopoietic progenitors (bone marrow CD34+ cells). In keeping with its essential role during terminal myeloid differentiation and its localization to chromosome 5q31.3, a region often deleted in myeloid leukaemia (more especially in acute myeloid leukaemia and myelodysplasia), RINF has been suggested as a promising tumour suppressor candidate at that locus in some myeloid malignancies.
Because RINF expression is not restricted to the hematopoietic tissue and may also be involved in development and/or homeostasis of other tissues, RINF expression in some solid tumours derived from different tissues have been investigated. It is shown in PCT application WO 2009/151337 that this gene could have a deregulated expression in some malignant tissues compared to their normal tissues of origin. Indeed, RINF mRNA expression was examined in solid tumour samples from patients suffering from breast cancer, and RINF expression was significantly higher in breast tumours compared to normal breast tissues controls.
Further, in PCT application WO 2010/085153 it is shown that measurement of RINF mRNA in breast cancer tumours, could be informative for overall survival of these breast cancer patients. In this application, it is also described a “kit” for detection of RINF mRNA by quantitative RT-PCR.
Leukaemia (American English) or leukaemia (Standard English; Greek leukos , “white”; aima
, “blood”) is a cancer of the blood or bone marrow characterized by an abnormal increase of blood cells, usually leukocytes (white blood cells).
The major forms of leukaemia can be divided into four main categories. Myelogenous and lymphocytic/lymphoblastic leukaemias, each have acute and chronic forms. The terms myelogenous or lymphocytic/lymphoblastic denote the cell type involved. In addition, within each category, distinct leukaemias are defined according to a combination of morphology, immunophenotype, and cytogenetic features in addition to clinical symptoms.
Acute leukaemia is a clonal disease of hematopoetic stem cells. For example, in the United States more than half of all new leukaemias are acute leukaemias. Said acute leukaemias can be differentiated into acute myelogenous leukaemia (AML), also called acute non-lymphocytic leukaemia and acute lymphocytic or acute lymphoblastic leukaemia (ALL) based on whether hematopetic stem cells have been differentiated along the lymphoid or myeloid lineage. In addition, chronic types of leukaemia are differentiated into chronic myelogenous leukaemia (CML) or chronic lymphocytic/lymphoblastic leukaemia (CLL).
Among leukaemia, acute myeloid leukaemia (AML) represents a distinct group of disease with heterogeneous genetic basis, pathophysiology, and prognosis. In the past, the karyotype of the AML cells has emerged as the most important prognostic factor, and patients can be classified into favourable, intermediate, and unfavourable prognostic groups according to the number and the specific types of chromosomal aberrations. However, almost half of all adult AML patients present with a normal karyotype at diagnosis. These patients are usually assigned to the intermediate prognostic group. More recently, mutations in specific genes that allow the identification of prognostic subgroups in cytogenetically normal (CN) AML have been described. Internal tandem duplications (ITD) of the fms-like tyrosine kinase 3 (FLT3) gene are strong predictors of inferior outcome. Mutations in the nucleophosmin 1 (NPM1) gene lead to cytoplasmic localization of the NPM protein and are a favourable prognostic factor, especially in patients lacking FLT3 ITD. Other prognostically relevant alterations include mutations in the MLL and CEBPA genes as well as overexpression of WT1, MN1, BAALC, ERG, and EVI1(MECOM). However, in approximately 24% of CN-AML cases, none of the aforementioned mutations can be detected. These findings illustrate that CN-AML itself constitutes a heterogeneous disease and that there probably are many genetic alterations in CN-AML to be discovered that affect response to treatment and survival.
In the case of leukaemia, like ALL, AML, CLL and CML, and especially in the case of AML and CN-AML, but also with CBF-AML, these prognostic indicators are very important to help the physicians to distinguish the group of patients that would more likely benefit from a chemotherapy (usually, disease with a favourable prognosis) from patients that (more probably) would not, and for instance, that should be considered for autologous or allogenic stem cell transplantation (these patients present usually with unfavourable prognosis and age below 60). In other terms, prognostic factors are of very high potential for the treatment decision making in these malignant haemopathies and additional prognostic markers are needed.
The inventors have now surprisingly found that the level of RINF expression correlates with the survival of patients with leukaemia, the progression of the disease, the risk of relapse of leukaemia more precisely an acute myeloid leukaemia, more precisely an acute myeloid leukaemia with normal karyotype.
The present invention thus relates to methods for determining the prognosis for survival, the progression of the disease, the risk of relapse of leukaemia, and for testing the effect of treatment regimens. The invention also relate to a kit for determining the prognosis for survival, and for testing the effect of treatment regimens.
The microarray dataset (Affymetrix GeneChip Human Genome HG-U133B) performed by Metzeler K H, et al., Blood. 2008 Nov. 15; 112(10):4193-201 (n=163 patient samples) was downloaded from the Gene Expression Omnibus website (http://www.ncbi.nlm.nih.gov/geo/) with accession number GSE12417. The whole raw data were normalized using RMA (Robust Multiarray Averaging method) with the Expression Console software from Affymetrix. The CXXC5 mRNA expression was then calculated as the mean intensity of the 3 probesets targeting CXXC5 (222996_s_at, 224516_s_at and 233955_x_at). The patients have been classified in two equivalent groups (A), according to an expression above (High, n=81) or below (Low, n=81) the median, or in 3 equivalent groups (B and C), according to a High (n=55), an Intermediary (n=54), or a Low (n=54) RINF expression level. For panel C, the Low (n=54) and Intermediary (n=54) groups have been fused. Note that because of an odd number of patients (n=163), the patient at the median has been censored for the 2 groups stratification and were not exactly equivalents for the 3 groups stratification (n=55 versus 54). The patient groups with high or low CXXC5 mRNA (RINF) were then correlated with the clinical outcomes concerning survival that were also accessed through the Gene Expression Omnibus website. The Kaplan-Meier curves (for survival analysis) and the log-rank test were performed by using the statistical SPSS 15.0. P values (log-rank test) of the comparison of the various groups of patients are indicated in the panels.
The microarray datasets (Standford microarrays) performed by Gaidzik V I, et al., J Clin Oncol. 2011 Apr. 1; 29(10):1364-72 (n=269, but n=266 patient samples with CXXC5 expression data available) was downloaded from the Gene Expression Omnibus website (http://www.ncbi.nlm.nih.gov/geo/) with accession number GSE23312. Fluorescence ratios were normalized by mean-centering genes for each array and then mean-centering each gene across arrays. The CXXC5 mRNA expression was then extracted and patients have been classified in three equivalent groups (A and B), according to a High (n=88), an Intermediary (n=89), or a Low (n=89) RINF expression level. For panel B, the High (n=88) and Intermediary (n=89) groups have been fused (n=177). Note that the patient number were not exactly equivalents for the 3 groups stratification (n=89, 89 versus 88) since the total number of patients was not a multiple of 3 (n=266). The patient groups with high, Intermediary, and low CXXC5 mRNA were then correlated with the clinical outcomes concerning survival that were also accessed through the Gene Expression Omnibus website. The Kaplan-Meier curves (for survival analysis) and the log-rank test were performed by using the statistical SPSS 15.0. P values (log-rank test) of the comparison of the various groups of patients are indicated in the panels.
In a first aspect, the present invention relates to a method for determining the progression of the disease or a prognosis for survival of a patient with leukaemia, the risk of a relapse of leukaemia in a patient diagnosed and, optionally, treated for leukaemia, characterized in that said method comprising:
As used herein, the term “subject” or “individual” or “patient” which is used herein interchangeably refers to an individual or a subject or a patient in need of a therapy or suspected to be afflicted with a condition or disease, namely leukaemia. Preferably, the subject or individual is a vertebrate even more preferred a mammal, particularly preferred a human.
The method according to the present invention is preferably conducted by collecting a sample from the individual and determining in vitro the level of RINF using appropriate means.
The term “control sample” or “reference sample” as used herein refers e.g. to a sample of an individual of the same species which individual is not suffering from leukaemia. Alternatively, the “control sample” or “reference sample” is a sample representing the median of a panel of patients afflicted with leukaemia. In another embodiment, the “control sample” is a cell line sample (for instance such as NB4, HL60, K562, MCF7).
A sample according to the invention is a biological material, which has been obtained from an individual. The term “sample” and “biological sample” are used herein interchangeably. In particular, said terms include material obtained from blood, plasma, tissue, bone marrow, serum or tumour, tumour biopsy or neoplastic cell containing sample.
The expression “level” or “amount” is meant to describe the relative level of said molecules according to the present invention relative to the same molecule in a control sample or reference sample, or the absolute amount of said molecules according to the present invention. Relative means that no distinct amounts such as mole or milligram per litre etc. are stated, but that for example is stated the sample contains more, less or the same amount of a certain molecule as compared to a control sample. The term “more, less or the same amount” in this situation includes also arbitrary units.
With “elevated” or “higher” and on the other side “decreased” or “lower” according to the invention is meant, that the molecule is present in a sample in higher (or lower, respectively) quantities, or amounts or concentration, as compared to another sample, or as compared to a control sample or as compared to a reference sample or as compared to a reference value, regardless if these measurements are relative or absolute measurements. Preferably, the molecule which is increased or decreased is present in a concentration, or quantity or amount which is at least 10%, like at least 20%, e.g. at least 30%, or 50% above or below the value to which it is compared. In other words, preferably, the molecule is increased or decreased at least 2 fold, e.g. 3 fold, 4 fold or even 5 fold or more above or below the level and/or amount in the control or reference sample. For example, the molecule in the sample is higher than 4.5 fold time the level of NB4 cells measured in the reference sample.
With “stratification of a subject” according to the invention is meant to determine the therapy regimen for the treatment of leukaemia. In particular, said stratification includes determining whether said subject will benefit from a specific treatment, irradiation chemotherapy, or stem cell transplantation.
Prognosis is a medical term to describe the likely outcome of an illness. Here, a good “prognosis for survival” correlates with high rate survival of the patients and “bad prognosis for survival” correlates with a low rate of survival of the patient group.
Thus, in one aspect, the present invention relates to a method for determining a prognosis for survival for a patient with leukaemia, wherein said method comprising:
(a) determining a measure for the level of RINF expression in a biological sample from said patient,
(b) comparing the level of RINF expression in said sample to a reference level of RINF,
wherein a level of RINF expression lower than the reference level in said sample correlates with increased survival probability or rate of said patient, and wherein a level of RINF expression higher than the reference level in said sample correlates with decreased survival probability or rate.
In this connection, the terms “a measure for the level” and “level” are used interchangeably herein.
In a preferred embodiment, said biological sample is whole blood, serum, plasma, liquor, bone marrow, a tumour, or a tumour biopsy or neoplastic cell containing sample. In fact, the biological sample can be a fraction of blood or bone marrow. for instance, it is a preferably PBMC (peripheral blood mononuclear cells) or BMMC (bone marrow mononuclear cells), isolated after ficoll-density gradient separation, and/or CD34+ cell sorting enrichment.
A preferred embodiment relates to acute myeloid leukaemia (AML). Moreover, it is preferred that the leukaemia is a leukaemia with normal karyotype or CBF, more preferable an acute myeloid leukaemia with normal karyotype.
In a preferred embodiment said measure for the level of RINF expression is determined by quantification of the expression of mRNA which encodes for a RINF protein, or a quantification of a nucleic acid comprising the sequence of SEQ ID NO1 or SEQ ID NO 2, or a functional fragment or variant thereof, or a functionally equivalent isolated DNA sequence hybridizable thereto.
In this connection, the term “hybridizable thereto” refers to conditions wherein sequences hybridize under stringent hybridization conditions (see, T. Maniatis et al., Cold Spring Harbor Laboratory (1982), molecular Cloning/ a laboratory manual, pages 387 to 389) to the sequences of Seq ID. No. 1 or 2. An example of stringent hybridization condition is hybridization at 4×SSC at 65° C., followed by a washing in 0.1×SSC at 65° C. for an hour. Alternatively, an exemplary stringent hybridization condition is in 50% formamide, 4×SSC at 42° C.
Further, the term “functional fragment” refers to fragments of Seq. ID. Nos. 1 or 2 having the same functionality as the polypeptide encoded by Seq. ID. Nos. 1 or 2, respectively. Moreover, the term “variant” refers to molecules having the same functionality as the nucleic acid molecules of Seq. ID Nos. 1 and 2 or the polypeptides encoded by said sequences, like the polypeptide of Seq. ID. No.3.
In a further preferred embodiment is the level of RINF expression relative to said reference level used to determine a proper course of treatment for said patient.
In a preferred embodiment is the level of RINF expression determined by quantitative RT-PCR. More preferable, said quantitative RT-PCR uses oligonucleotides targeting SEQ ID NO 1 or SEQ ID NO 2 for determining the RINF expression, and more preferable said RT-PCR uses primers amplifying exon 3 and 4, or exon 1 and 2 of SEQ ID NO 3.
Preferable, the level of RINF expression is determined based on the relative expression of RINF normalized to the expression of the rpP2 gene, also known as RPLP2 ribosomal protein, large, P2, (HGNC: 10377). Preferable, the primers for the detection of SEQ ID NO 1 or 2 are
6-FAM is a reactive water-soluble fluorescent dye. It is an isomer of carboxyfluorescein, widely used to label oligonucleotides for real-time PCR applications. 6-FAM is excited maximally at 492 nm and emits maximally at 517 nm.
Cy5 (Cyanine-5) is a reactive water-soluble fluorescent dye of the cyanine dye family. Cy5 is excited maximally at 649 nm and emits maximally at 670 nm, in the far red part of the spectrum.
BBQ means BlackBerry Quencher is a “dark quencher” for every fluorescent dye. Non-fluorescent quenchers are fundamental for multiplex applications with more than one dye. A dark quencher is a substance that absorbs excitation energy from a fluorophore and dissipates the energy as heat (while a typical (fluorescent) quencher re-emits much of this energy as light).
Of course, any other marker or label may be used for effecting the analysis accordingly. The skilled person is well aware of suitable label or marker molecules.
Preferable, the PCR amplification is conducted by an initial denaturation at 95° C. for 5 min, and then the samples run through 44 cycles of the following conditions: denaturation for 10 seconds at 95° C. and elongation at 55° C. for 20 seconds.
In a further embodiment the level of RINF expression is determined immunochemically based on an antibody-based detection system. Said antibody can be a polyclonal antibody, and is more preferable a monoclonal antibody. Preferable, said antibody is interacting with an epitope of a protein or protein sequence of SEQ ID NO 3, and more preferable said antibody is interacting with the amino acids 45-48 of SEQ ID NO 3.
In a further embodiment, the RINF expression is measured by a DNA, RNA or protein array.
Suitable methods to detect the level, e.g. the relative level and/or absolute amount of RINF in the samples are well known in the art. For example, suitable methods include suitable mass spectrometry methods, e.g. matrix assisted laser desorption ionisation (MALDI), continuous or pulsed electrospray ionisation (ESI) and related methods such as ionspray or thermospray or massive cluster impact. The ion sources can be matched with detection formats including linear or non-linear reflection time of light (TOF), single or multiple quadrupole, single or multiple magnetic sector, Fourier transformation ion cyclotron resonance (FTICR), ion trap, and combinations thereof. Other mass spectrometic methods suitable are for example fast atom bombardment (FAB), mass spectrometry, surface enhanced laser desorption (ionisation) (SELDI), mass spectrometry, etc.
Further, suitable immunologic methods among other are enzyme link immunoassays (ELISA), sandwich, direct, indirect, or competitive ELISA assays, enzyme link immunospotassays (ELlspot), radio immunoassays (RIA), flow-cytometry assays (FACS), immunohistochemistry, Western Blot, fluorescence resonance energy transfer (FRET) assays, protein chip assays using for example antibodies, antibody fragments, receptor ligands or other agents binding the molecules of the invention.
Among other Northern Blot or Southern Blot hybridization, nucleic acid dot or slot Blot Hybridization, in situ hybridization, nucleic acid chip assays (for example using RNA, DNA or other nucleic acids to specifically capture the nucleic acid of interest), polymerase chain reaction (PCR), reverse transcriptase-PCR (RT-PCR), real time PCR, and in particular, real time quantitative polymerase chain reaction (RQ-PCR) after reverse transcription may be used as molecular biology methods to detect the molecules of the invention.
Further methods, such as nuclear magnetic resonance (NMR), fluorometry, colorimetry, radiometry, luminometry or other spectrometric methods, liquid chromatography, capillary chromatography, thin-layer chromatography, plasmon resonance, one-or-two gel dimensional electroporesis etc. can be used to detect the molecules of the invention.
In another preferred embodiment the level and/or amount of RINF is determined on mRNA level. Particular preferred the determination is conducted by RQ-PCR, for example applying known real time PCR-methods. Another preferred embodiment relates to the determination of the level and/or amount of RINF on protein level. For example, said level may be determined by immunological methods as outlined above using specific anti-RINF antibodies.
In a further embodiment, said method further comprises a step (c);
(c) classifying said patient as belonging to either a first or a second group of patients, wherein said first group of patients having levels of RINF expression lower than the reference level is classified as having an increased likelihood of survival, slower progression of the disease, better prognosis or lower risk or relapse compared to said second group of patients having levels of RINF expression higher than the reference level.
In a further embodiment, said method further comprises a step (c);
(c) classifying said patient as belonging to either a first or a second group of patients, wherein said first group of patients having levels of RINF expression lower than said second group of patients, and where the first group of patients is classified as having an increased likelihood of survival, slower progression of the disease, better prognosis or lower risk or relapse compared to said second group of patients.
A second aspect of the present invention relates to a method for monitoring the effectiveness of a course of treatment for a patient with leukaemia, wherein said method comprising:
(a) determining a level of RINF expression in a biological sample from said patient prior to treatment, and
(b) determining the level of RINF expression in a neoplastic cell-containing sample from said patient after treatment, whereby comparison of the level of RINF expression prior to treatment with the level of RINF expression after treatment indicates the effectiveness of said treatment, wherein a decrease in the level of RINF expression after treatment indicates that treatment is effective against said leukaemia.
In addition, the present invention relates to a method for the stratification of the patient being afflicted with leukaemia to determine the therapy regimen for the treatment of leukaemia comprising
A third aspect of the present invention relates to a use in accordance with any of the method claims, wherein at least one detection member for RINF is used in a kit for determining a prognosis for survival for a patient with leukaemia.
A forth aspect of the present invention relates to a kit for determining a prognosis for survival for a patient with leukaemia, characterized in that said kit comprises compounds capable of detecting the level of RINF expression in a biological sample.
Preferable embodiments for the second, third and forth aspects (independently for each aspect) are indicated below:
said leukaemia is AML, ALL, CML, or CLL, preferably acute myeloid leukaemia, and more preferable acute myeloid leukaemia with normal karyotype or CBF (Core-binding-factor) (CBF-AML are characterized by translocation t(8:21) or inversion inv(16), respectively). CBF-AML respond usually well to chemotherapy. However, some of these patients do not respond well to therapy and it has been recognized that this groups is characterized by high RINF expression.
said biological sample is obtained from bone marrow, blood or tissue, like plasma, serum, liquor, a tumour, or a tumour biopsy or neoplastic cell containing sample.
said measure for the level of RINF expression is determined by quantification the expression of mRNA which encodes for a RINF protein, or a quantification of a nucleic acid comprising the sequence of SEQ ID NO1 or SEQ ID NO 2, or a functional fragment or variant thereof, or a functionally equivalent isolated DNA sequence hybridizable thereto.
the level of RINF expression relative to said reference level is used to determine a proper course of treatment for said patient.
the level of RINF expression is determined by quantitative RT-PCR. More preferable, said quantitative RT-PCR uses oligonucleotides also termed Hydrolysis Probes targeting SEQ ID NO 1 or SEQ ID NO 2 for determining the RINF expression, and more preferable said RT-PCR uses primers amplifying exon 3 and 4, or exon 1 and 2 of SEQ ID NO 3.
In this connection, the term “Hydrolysis probes” are used to define sequence specific DNA oligonucleotides that are chemically modified (labeled with both a fluorescent dye and a quencher dye) in order to easily monitor the concentration of a specific DNA during a quantitative real-time Polymerase Chain Reaction (qRT PCR).
The fluorescence emitted (when excited by an external light source at each PCR cycle) is proportional to the amount of the specific DNA product formed.
The Hydrolysis Probe chemistry relies on the 5′-3′ exonuclease activity of Taq polymerase, which degrades a hybridized non-extendible DNA probe during the extension step of the Polymerase Chain Reaction (PCR). This probe is designed to specifically hybridize to a region within the amplicon and is dual-labeled with a fluorecent dye and a quencher. The close proximity of the quencher suppresses the fluorescence of the reporter dye. Once the exonuclease activity of Taq polymerase degrades the probe, the fluorescence of the reporter increases at a rate that is proportional to the amount of template present.
the level of RINF expression is determined based on the relative expression of RINF normalized to the expression of the rpP2 gene.
the primers for the detection of SEQ ID NO 1 or 2 are
the primers for the detection of rpP2 are 5′-atgcgctacgtcgcc-3′ (Seq. ID No. 6), 5′-ttaatcaaaaaggccaaatcccat-3′ (Seq. ID No. 7) and Cy5-agctgaatggaaaaaacattgaagacgtc-BBQ (Seq. ID No. 9).
the PCR amplification is conducted by an initial denaturation at 95° C. for 5 min, and than the samples is run through 44 cycles of the following conditions: denaturation for 10 seconds at 95° C. and elongation at 55° C. for 20 seconds.
the level of RINF expression is determined immunochemically based on an antibody. Said antibody can be a polyclonal antibody, and is more preferable a monoclonal antibody. Preferable, said antibody is interacting with an epitope of a protein or protein sequence of SEQ ID NO 3, and more preferable said antibody is interacting with the amino acids 45-48 of SEQ ID NO 3.
the RINF expression is measured by a DNA, RNA or protein array.
First-strand cDNA synthesis (RT) was carried out starting with total RNA (1 μg) in a 20 μl volume using oligo-dT primers with Transcriptor Reverse Transcriptase (Roche, Cat. No 05 531 287 001) in accordance with the manufacturer's instructions. Quantitative PCRs were performed using specific Hydrolysis Probes targeting the CXXC5 gene on a Light Cycler 480 machine (Roche) in accordance with the manufacturer's instructions of the kit Lightcycler® 480 ProbesMaster (Cat. N° 04 707 494 001). Relative mRNA expressions were normalized to rpP2 gene expression in a two-colour duplex reaction. Primers for detection of CXXC5 (5′-tccgctgctctggagaag-3′ (Seq. ID No. 4), 5′-cacacgagcagtgacattgc-3′ (Seq. ID No. 5) and 6FAM-aacccaaagctgccctctcc-BBQ (Seq. ID No. 8)) and rpP2 (5′-atgcgctacgtcgcc-3′ (Seq. ID No. 6), 5′-ttaatcaaaaaggccaaatcccat-3′ (Seq. ID No. 7) and Cy5-agctgaatggaaaaaacattgaagacgtc-BBQ (Seq. ID No. 9)), were designed to be used in the same conditions of real-time PCR amplification. After initial denaturation at 95° C. for 5 min, samples were run through 44 cycles of the following conditions: denaturation for 10 seconds at 95° C. and elongation at 55° C. for 20 seconds.
Analysis of CXXC5 mRNA Expression in a Microarray Dataset and Correlation Analysis with the Overall Survival of Acute Myeloid Leukaemia Patients with Normal Cytogenetics.
One microarray dataset for which (1) CXXC5 mRNA expression data, and (2) survival data were available online, was downloaded from the Gene Expression Omnibus website (http://www.ncbi.nlm.nih.gov/geo/) with accession number GSE12417. This microarray dataset was originally performed by Metzeler et al., see above in order to develop a gene expression signature to predict treatment outcome for acute myeloid leukaemia patients with normal karytotype (n=163 patient samples). For each microarray platform (Affymetrix GeneChip® Human Genome U133A, Affymetrix GeneChip® Human Genome U133B, and Affymetrix GeneChip® Human Genome U133 Plus 2.0), the whole raw gene expression data were normalized using RMA with the Expression Console software from Affymetrix. The CXXC5 mRNA expression was calculated as the mean intensity of the 3 probe sets targeting CXXC5 (222996_s_at, 224516_s_at and 233955_x_at). Gene expression data were also extracted for some already approved prognosis factors WT1 (206067_s_at and/or 206067_s_at), MN1(205330_at), BAALC (222780_s_at), ERG (241926_s_at), MECOM (EVI, 226420_at). Patients were then clustered into two (above or below median) or three (high, intermediary or low gene expression) groups according to their CXXC5 mean intensity. The patient groups with high or low CXXC5 mRNA (RINF) were then correlated with the clinical outcomes concerning survival that were also accessed through the Gene Expression Omnibus website (“E-GEOD-12417.sdrf.xls” file). The Kaplan-Meier curves (for survival analysis) and the log-rank test were performed by using the statistical SPSS 15.0.
The expression of RINF can also be determined by an antibody approach. Western blotting was carried out as previously described by Wu Y L, Dudognon C, Nguyen E, et al. Immunodetection of human telomerase reverse-transcriptase (hTERT) m-appraised: nucleolin and telomerase cross paths. J Cell Sci. 2006; 119:2797-2806.
Customized rabbit polyclonal peptide-specific antibody against RINF was produced by Biogenes GmBH. The immunogenic peptide corresponds to amino acids 45-58 of the RINF protein. Antibody specificity was confirmed by competitive inhibition of the western-blot signal by addition of the immunogene peptide to the primary antibody solution. Briefly, blots were incubated with primary antibody against RINF (polyclonal antibody), and then with an appropriate peroxydase conjugated secondary antibody. Detection of protein was performed using a chemiluminescent detection system (Amersham Pharmacia Biotech).
For the expression studies of the above mentioned gene/protein, RINF, any method for quantitatively detecting the amplified product can be used, including, for example using any fluorescent dyes or labeled probes and standard methods.
Quantification of a sample containing an unknown number of target sequences typically is carried out with reference to a “standard curve” generated from a series of amplifications of samples containing the target sequence in a range of known amount. The standard curve is used to calculate an input copy number from the signal generated during an amplification. Thus, the unknown target sequence copy number in the sample of interest is estimated using the standard curve calculating the copy number that previously was determined to yield a signal equal to that observed. The concentration of the target sequence in the sample then is calculated from the input copy number and the sample size, which is determined prior to the reaction.
Quantitative estimates can be sensitive to variability in either the input sample size or in the reaction efficiency. The effect of inter-reaction variability of the input sample size on the calculated RINF concentration can be eliminated by using a control gene. A control gene is selected which provides an independent measure of the amount of RNA in the sample. The calculated concentration of the RINF mRNA is adjusted based on the independent measure of the sample.
Variability in the amplification efficiency between the reactions used to generate the standard curve and the reaction used to assay the sample of interest can affect the applicability of the standard curve. Carrying out the reactions used to generate the standard curve simultaneously with the reaction used to assay the sample of interest, using the same “master mix” of amplification reagents, and, preferably, in adjacent wells in the same thermal cycler, will minimize the inter-reaction variation in efficiency. Alternatively, an in thermal standard can be used to adjust the results to account for variation in amplification efficiency.
The effect of inter-reaction variability of reaction efficiency between the reactions used to generate the standard curve and the reaction used to assay the sample of interest can be eliminated by using a sample of interest and is amplified with internal standard. The internal standard is added to reaction in a known copy number and co-amplified along with the RINF mRNA target. The signal generated from the known amount of the internal standard provides an indication of the overall reaction efficiency which can be used to adjust the estimate difference in copy number to account for the difference in reaction efficiencies.
The internal standard is a nucleotide sequence that contains the same primer binding sites present in the target such that it is amplified by the same primer pair, but is distinguishable from the target sequence either by length or, preferably, by the presence of a unique internal sequence. The internal standard is included in a known copy number amplifications of the sample of interest and is amplified with approximately the same efficiency as the target sequence. Any change in the signal generated by amplification of the internal standard relative to the signal expected from the standard curve reflects a change in the overall reaction efficiency and is used to adjust the estimate of the target sequence copy number correspondingly.
The fourth aspect of the invention relates to kits comprising useful components for practicing the present method: A useful kit can contain oligonucleotide primers and, optionally, probes specific for the targets regions of the RINF mRNA described. Other optional components of the kit include, for example, any standard products known by skilled scientist in the field for the quantitative RT-PCR amplification like, agents to catalyze the synthesis of primer extension (enzymes, buffer), the deoxynucleotide triphosphates (dNTP), internal standard nucleic acids, a reference RNA (positive control), non-amplified control nucleic acid (negative control), appropriate buffers for PCR or hybridization reactions, and instructions for carrying out the present method. For examples, the reference control can be RNA from cell lines such as NB4, K562, HL60, or MCF7.
Another kit, or other component in the same kit, can contain SYBR green, oligonucleotide primers and, optionally, specific for the targets regions of the RINF. Other components of the kit include, substrate nucleotide triphosphates, internal standard, agents to catalyze the synthesis of primer extension, positive control, and negative control.
The examples of the present invention presented here are provided only for illustrative purposes and not to limit the scope of the invention.
The invention and the results of the experiments leading to the invention will now be further described, with reference to the following figures:
a and 6b show the prediction of survival outcomes by gene expression measurement of prognosis factors WT1, MN1, BAALC, ERG, MECOM (EVI1) in the same cohort of AML patients with normal karyotype CN-AML (n=163). Gene mRNA expressions were extracted with the specific probesets WT1 (206067_s_at and/or 206067_s_at), MN1(205330_at), BAALC (222780_s_at), ERG (241926_s_at) and MECOM (EVI, 226420_at). Cumulative survivals (Kaplan-Meier) are represented according to mRNA expression levels detect by affymetrix arrays (HG-U133A, HG-U133B or U133 plus 2.0). Like for RINF mRNA, the patients have been classified in two equivalent groups (A), according to an expression above (High, n=81) or below (Low, n=81) the median, or in 3 equivalent groups (B and C), according to a High (n=55), an Intermediary (n=54), or a Low (n=54) RINF expression level. Note that because of an odd number of patients (n=163), the patient at the median has been censored for the 2 groups stratification and were not exactly equivalents for the 3 groups stratification (n=55 versus 54). P values (log-rank test) of the comparison of the various groups of patients are indicated in the panels. Notably, as shown on
Moreover, a cohort of ALL patients was tested wether the RINF mRNA expression could correlate with the risk of relapse. For all the ALL patients (n=197) of this cohort, RINF expression data were analyzed by microarray analysis (study GSE13576) as described for the AML cohort (GSE12417). As shown in
From the above results it is clear that RINF represents a measure allowing for determining the progression of the disease or a prognosis for survival of the patient with leukaemia, in particular, acute and chronic lymphocytic/lymphoblastic or myeloid leukaemia, or the risk of a relapse or leukaemia in a patient diagnosed and, optionally, treated for leukaemia. In addition, RINF allows to stratify therapy regimens of patients afflicted with leukaemia. This is in contrast to other markers described so far. For example, as shown herein, other markers described in the art, like MN1 or WT1 do not allow to identify the different groups of patients afflicted with leukaemia, or at least in a lower extend that it is possible for RINF and, thus, do not allow to judge on a higher risk of relapse or on the progression of the disease as well as on the prognosis for survival and for stratifying the therapy regimens as it is possible based on RINF. In
Furthermore, studies on chronic lymphoid leukaemia (CLL) (microarray study GSE10138) demonstrated that high RINF mRNA expression is associated with a higher risk of progression, see table 2, below:
Moreover, in chronic myeloid leukaemia based on the data of GSE4170, RINF expression is increased during the progression of CML from chronic phase to blast crisis, see
Quantifying the relative mRNA level of RINF in neoplastic cells from patients with a leukaemia can help doctors determine whether or not a tumour is of good or bad prognosis, as well as if a certain treatment is likely to succeed. In the case of leukaemia, and especially in the case of AML, these prognostic indicators are important for the physicians to distinguish the group of patients that would more likely benefit from a chemotherapy (usually, disease with a favourable prognosis) from patients that would not and should be considered for stem cell transplantation (usually, patients with unfavourable prognosis and age below 60).
Our results demonstrate that quantification of RINF mRNA expression could be a significant predictor of patient survival and leukaemia progression.
Indeed, by extracting the CXXC5 mRNA expression data from several independent microarray study available in public databases, and correlating it with the clinical outcome, we have tested and demonstrated for the first time, a strong correlation, between a high RINF mRNA expression and low survival rate for patients suffering from leukaemia, more precisely AML, ALL, CLL, and CML, more precisely AML with normal cytogenetics as well as with AML-CBF (translocation t(8;21) or inv(16)).
At the best of our knowledge, no previous study has examined the relationship between the RINF mRNA expression and a patient's prognosis in leukaemia. This inventive idea was tested because we have been the first to observe that this gene was playing a important role into differentiation of myeloid cells and was deregulated in cancer cell types. However, and importantly, these results were not obvious because many genes, shown to be de-regulated in cancer, have in fact no predictive value toward a patient survival or response to therapy. Furthermore, while WO2009/151337 describe that the induction of RINF mRNA expression (by retinoic acid) correlated with a growth arrest of the leukemic cell model NB4 in vitro of Acute Promyelocytic Leukemia (AML-with t(15;17)) (and the clinical remission relapse of the patients). Here, we surprisingly found the opposite trend in leukemia (AML, ALL, CLL), since the high RINF expression at diagnosis correlates with a more agressive phenotype of the leukemic cells (a shorter survival rate of patients, or a lower probability of response to therapy, or a higher probability to relapse, or a higher probability to progress into disease at higher risk).
Moreover, it was not “obvious” also because we did not find this trend in an other malignant haemopathies (myeloma) in which High RINF does not seem to correlate with the survival. This is an important area of research in cancer because there are little data to help physicians chose which treatment is best for which patients or to determine when a change in treatment is warranted.
The RINF mRNA level can be measured in the biological sample including blood, liquor, bone marrow, tumour, or tumour biopsy, taken out at the time of surgery by using the kit and methods according to the present invention.
Potentially, this tool could be useful in the clinic for clinicians to take their decisions about whether a treatment is helping. Our ultimate goal is to continue effective treatment, but spare patients the side effects of a treatment that is destined to fail.
To conclude, the present invention provides a marker with superior properties over prior art marker allowing to determine the progression of leukaemia in a patient afflicted therewith or allow to provide a prognosis for survival of a patient with leukaemia. In addition, the present invention allows to determine the risk of a relapse of leukaemia in a patient diagnosed and, optionally, treated for leukaemia based on RINF expression. Further, the present invention allows to stratify therapy regimens of individuals afflicted with leukaemia. Moreover, as demonstrated herein in all four major types of leukaemia, ALL, CLL, AML, CML, RINF represents a suitable marker, and, strikingly, by comparing RINF for the first time in the same cohort with other well known markers in the art, like MN1, WT1, ERG, MECOM or BAALC, RINF has a clearly superior capability to predict the survival over these other markers.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20101053 | Jul 2010 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2011/062537 | 7/21/2011 | WO | 00 | 4/30/2013 |
