Patent Application
20220218621
The present invention applies to the medical field and, in particular, to tumor diagnosis or treatment.
Surgical therapy in oncology remains the most effective treatment for the eradication of solid tumors. The success of the therapy depends almost exclusively on the surgeon's ability to resect the tumor margins. This ability is currently not easily standardized and is entrusted to the experience and tactile/visual sensitivity of the surgeons themselves. The use of highly selective diagnostic compounds would allow the surgeon to visualize the margins of the tumor within healthy tissue during the surgical procedure either directly or through imaging methods.
The effectiveness of imaging methods, such as PET, MRI, and ultrasound in tumor diagnosis, depends on their detection sensitivity. Selective accumulation of contrast molecules (e.g. ICG, gadolinium, 18FDG, microbubbles) would make it possible to increase the signal-background noise ratio.
Over the past twenty years, many nanoparticles of different nature (liposomes, extracellular vesicles, biocompatible nanoparticles) have been suggested as pathotropic delivery system in the oncological field; however, few methods have achieved clinical practice, e.g. such as lipoplatin or liposomal doxorubicin.
Recently, the publications by M. Garofalo et al. (Journal of Controlled Release 2018 Aug. 10; 283:223-234; Journal of Controlled Release, 2019 Jan. 28; 294:165-175; Viruses, 2018 Oct. 13;10(10)) report studies on the effect and selectivity of oncolytic and paclitaxel viruses enveloped in extracellular vesicles in the treatment of lung cancer cells.
Although limited, these few examples of applications are significant, because these formulations have made it possible to significantly reduce the toxicity of chemotherapeutic drugs in the treatment of different types of tumor.
However, there are limitations in the systems suggested so far, the main ones of which are: 1) limited pathotropicity, 2) poor biocompatibility and 3) limited ability to deliver large molecules, typically represented by biological drugs.
International patent application WO 2019/077534 describes the isolation of exosomes from plasma and their possible therapeutic use, however without providing any practical examples of how the method can be carried out.
International patent application WO 2019/191444 describes the use of engineered exosomes through the transfection of nucleic acids which express a therapeutic protein for the delivery of therapeutic drugs to specific targets, in particular by virtue of growth factor gradients.
The inventors of the present patent application have surprisingly found that it is possible to use extracellular vesicles isolated from the plasma of oncological patients to deliver diagnostic or therapeutic drugs selectively to tumor cells.
In a first object, the present patent application describes extracellular vesicles isolated from the plasma of an oncological patient comprising drugs having diagnostic or therapeutic tumor activity.
In a second and third objects of the invention, a method for isolating and a process for purifying extracellular vesicles from an isolated sample of plasma of an oncological patient are described.
A fourth object describes a method for loading drugs with diagnostic or therapeutic activity into extracellular vesicles isolated from the plasma of oncological patients.
A fifth object describes the medical use of the extracellular vesicles isolated from the plasma of oncological patients and loaded with a drug having diagnostic and/or therapeutic activity for the diagnosis and/or treatment of tumors.
A further object describes a method for the diagnosis and/or therapy of tumors comprising the administration to a patient in need of extracellular vesicles isolated from the plasma of oncological patients and loaded with a diagnostic and/or therapeutic drug.
According to a first object, the present invention describes extracellular vesicles comprising diagnostic and/or therapeutic drugs for the selective delivery to a tumor tissue.
For the purposes of this invention, the term “extracellular vesicles” (hereafter sometimes abbreviated as “EV”) is suggested to comprise all types of membrane vesicles released into the extracellular space, regardless of their differences in biogenesis and composition.
Therefore, exosomes, microvesicles, and apoptotic bodies are included within this definition.
In particular, exosomes are small vesicles (30-150 nm) involved in intercellular communication, microvesicles are vesicles of 100-1000 nm, while apoptotic bodies originate from apoptotic cells and their size is between 1000-5000 nm.
For the purposes of the present invention, a diagnostic drug is a drug chosen from the group which comprises:
For the purposes of the present invention, a therapeutic drug is a tumor therapy drug and is preferably selected from the group which comprises:
According to a preferred aspect of the present invention, the described extracellular vesicles are isolated from blood plasma (hereinafter referred to as “plasma” for the sake of brevity).
According to a particularly preferred aspect of the present invention, the plasma is represented by the plasma of an oncological patient, i.e. a patient with an oncological pathology.
According to an aspect, the vesicles are isolated from the patient's own plasma (autologous use) to whom the vesicles are administered for diagnosis and/or cancer therapy, as reported below; alternatively, it is a different patient (heterologous use) from the one from whose plasma the vesicles are isolated.
For the purposes of the present patent application, the form of cancer from which the patient from whose plasma the extracellular vesicles are isolated is the same as the form of cancer from which the vesicles comprising the diagnostic or therapeutic drug are administered; alternatively, it is a different form of cancer.
In a preferred aspect of the present invention, the extracellular vesicles have a size between 50 and 300 nm.
According to another aspect of the invention, the vesicles have a zeta potential which is not modified by loading a diagnostic/therapeutic drug.
For the purposes of the present invention, the zeta potential is the net charge possessed by particles, i.e. the electrokinetic potential present in colloidal dispersions; in other words, the zeta potential is the potential difference between the dispersion medium and the stationary layer of fluid attached to the dispersed particle.
In a second and third object of the invention, a method for isolating and a process for purifying extracellular vesicles from the plasma of an oncological patient are described.
In particular, the method of the present invention comprises a step of preparing the plasma from an isolated sample of the patient's blood.
Such a step of preparing comprises, in particular, the steps of:
A1) treating an isolated blood sample of a patient with a suitable drug capable of inhibiting the coagulation cascade,
A2) subjecting the thus treated sample to a centrifugation step at low speed,
A3) separating the supernatant,
A4) subjecting the supernatant to a centrifugation step at high speed.
In particular, in step A1) the isolated blood is treated with ethylenediaminetetraacetic acid (EDTA) or alternatively with heparin or citrate.
For the purposes of the present invention, all subsequent steps must be carried out within a few hours of collection and preferably within 12 hours.
Step A2) of centrifugation is preferably carried out at the speed of 1600 RCF for a time of about 10 minutes at room temperature.
Step A4) of high-speed centrifugation is preferably carried out at a speed of about 3000 RCF for a time of about 10 minutes at room temperature.
Extracellular vesicles (EV) are thus isolated through the method as described above.
In a second and third object of the invention, a method for isolating and possibly also purifying extracellular vesicles from an isolated sample of plasma of an oncological patient are described.
In particular, the method for isolating comprises the steps of:
(B1) subjecting the isolated plasma sample to centrifugation,
B2) removing the supernatant.
More in detail, step B1) of centrifugation is preferably carried out at a speed of about 10,000 RCF for 120 minutes at a temperature of about 4° C.
Furthermore, step B1) is preferably carried out on an isolated plasma sample obtained as described above.
The solid deposit obtained from step B2) comprises extracellular vesicles, which can be resuspended in a suitable buffer solution.
If necessary, they can then be filtered.
In particular, said extracellular vesicles are resuspended in an appropriate buffer solution.
According to an aspect of the invention, if the extracellular vesicles are filtered, hydrophilic 0.1 μm mesh polytetrafluoroethylene (PTFE) filters are used to avoid contamination; e.g. phosphate buffer (PBS) containing bovine serum albumin (BSA), e.g. a concentration of approximately 0.5%, may be used.
For the purposes of the present invention, the suspension of extracellular vesicles in a buffer solution obtained as described above may be subjected to purification.
In a preferred aspect of the invention, said purification can be carried out by magnetic separation.
More in detail, if carried out, such purification comprises the steps of:
(C1) adding a solution containing magnetic beads bound to an appropriate antibody,
C2) incubating of the suspension of step C1) for an appropriate time,
C3) purifying in column by magnetic separation in a magnetic field,
C4) centrifuging the suspension of extracellular vesicles purified in step C3),
C5) removing the supernatant.
In step C1), a quantity of magnetic bead solution of about 20 μl may be added.
In particular, such magnetic beads are bound to an anti-human antibody CD81.
The incubation in step C2) is preferably carried out for 16 hours at 4° C.
More in detail, the column purification in step C3) comprises the steps of:
C3.a) loading the suspension onto a column for the magnetic separation in a magnetic field,
C3.b) washing with an appropriate solution to remove impurities. In a preferred aspect, the washing may be carried out with phosphate buffer solution followed by filtration according to the procedure in step B2,
C3.c) releasing extracellular vesicles by removing the magnetic field from the column and eluting with an appropriate solution. In a preferred aspect, the elution is carried out with a phosphate buffer solution, which is followed by appropriate filtration according to the procedure in step B2, and preferably at high pressure.
As regards to step C4), the centrifugation is preferably carried out at a speed of about 100,000 RCF for 120 minutes at a temperature of about 4° C.
After the removal of the supernatant, the vesicles are resuspended in an appropriate buffer solution, e.g. phosphate buffer (PBS), which is then filtered according to the procedure in step B2.
According to a particularly preferred aspect of the invention, the step of purification is not performed and, therefore, the process comprises only steps C4) and C5) above.
Therefore, according to such an aspect, the method proceeds with the steps of:
C1′) centrifuging the suspension of extracellular vesicles, and
C2′) removing the supernatant.
According to a fourth object of the invention, a method is described for loading drugs having diagnostic and/or therapeutic activity into extracellular vesicles isolated from the plasma of oncological patients.
In a preferred aspect, the loaded extracellular vesicles are obtained and possibly purified, according to the method of the present invention.
In particular, the method comprises the step D1) of incubating the extracellular vesicles for an appropriate time with a solution containing the diagnostic and/or therapeutic drug.
More specifically, the vesicles are incubated from a suspension comprising about 108-109 vesicles.
Preferably, such vesicles may be suspended in 1 ml of an appropriate buffer solution, e.g. phosphate buffer (PBS).
As described above, filtering, e.g. with hydrophilic, 0.1 μm mesh polytetrafluoroethylene (PTFE) filters, may follow.
The drug is incubated from a solution at an appropriate concentration, as a function of needs, e.g. such as the amount of drug to be delivered and as a function of the drug itself.
For the purposes of the present invention, the incubation is performed for a time of about 1 to 24 hours, preferably about 1 to 12 hours, as a function of needs, such as the amount of drug to be delivered and the nature of the drug itself.
The incubation is preferably carried out at 4° C.
After step D1) of incubating, the suspension can be subjected to the steps of:
D2) centrifuging, and
D3) removing the supernatant.
The extracellular vesicles thus loaded can be resuspended in an appropriate buffer solution, e.g. phosphate buffer (PBS), which is then filtered according to the procedure of step B2.
In particular, the step D2) is performed at a speed of about 150,000 RCF for a time of about 180 minutes at room temperature.
For the purposes of the present invention, given parameters of the method of loading the diagnostic and/or therapeutic drug depend on given factors, such as, for example: the volume of buffer solution to prepare the suspension to be centrifuged, the amount of incubation drug, the incubation time, the amount of solution for resuspension of extracellular vesicles loaded with the drug.
The identification of the precise conditions is considered to be within the expertise of a person skilled in the field.
The quantity will depend on the needs and the drug loaded inside the vesicles.
According to the fifth object of the invention, the medical use of the extracellular vesicles isolated from the plasma of oncological patients for the diagnosis and/or treatment of tumors is described.
In particular, as described above, the vesicles are isolated from the patient's own plasma to whom the vesicles are administered for diagnosis and/or cancer therapy (autologous use); alternatively, they are isolated from a patient's plasma to be subsequently used for medical use in a different patient (heterologous use).
For the purposes of the present patent application, the form of cancer from which the patient from whose plasma the extracellular vesicles are isolated is the same as the form of cancer from which the loaded vesicles are administered; alternatively, it is a different form of cancer.
The amount of preparation of loaded extracellular vesicles to be administered to the patient can be determined by the person skilled in the art based on needs.
In particular, the extracellular vesicles prepared according to the description above are administered intravenously.
In accordance with a further object describes a method for the diagnosis and/or therapy of tumors comprising the administration to a patient in need extracellular vesicles isolated from the blood plasma of oncological patients and loaded with a diagnostic and/or therapeutic drug as described above.
The type of drug and its quantity to be administered may be defined by the person skilled in the field as required.
In particular, the extracellular vesicles prepared according to the description above are administered intravenously.
The invention will be described further below by means of non-limiting examples.
A. Separation of Plasma from the Blood Sample
A preparation of extracellular vesicles prepared and purified according to Example 1 is loaded with the oncological therapeutic drug Paclitaxel.
Filtering with 0.1 μm filters may not be carried out.
10 μL of the cell suspension obtained from Example 1 are taken for subsequent characterization.
The number and size of the isolated EVs are determined using the Nanoparticle Tracking Analysis (NTA) (
In particular,
The panel on the left shows the results of the dimensional analysis using the NTA technique: curves are related to vesicles before and after loading and the non-enveloped viruses. The results of the charge analysis using the ELS technique are shown in the panel on the right: left, the vesicles before loading, center, the vesicles after loading with the virus, right, the non-enveloped virus.
The vesicles to be used must have a size between 50 and 300 nm and a zeta potential which is not modified by the inclusion of therapeutic drugs (e.g. oncolytic virus in the figure).
A preparation of 1*106 cells from a lung cancer cell line LL/2 (Lewis Lung carcinoma) was used for the test.
When the tumor has reached palpable size (diameter about 5 mm), basal autofluorescence emission was acquired to eliminate the “background noise”; the acquisition was obtained by gaseous anesthesia with diisoflurane and by measuring the fluorescence emission for 1 second of exposure through the IVIS Lumina II Quantitative Fluorescent and Bioluminescent Imaging device (PerkinElmer, Waltham, Mass., US).
The images are the basal fluorescence emitted by the animals (autofluorescence). The overlapping of reflected light and fluorescent images was done with Living Image Software 3.2 (PerkinElmer).
The EVs isolated from the plasma of oncological patients were loaded with an oncolytic virus as a therapeutic drug and with ICG as a diagnostic drug (EV1), as described in the procedure described above. 108 EVs were injected intravenously and 24 hours after injection fluorescence emitted in vivo from rats (in vivo imaging) was acquired, as described above.
At the end of the acquisition, the rats were sacrificed by cervical dislocation, dissected, and the fluorescence emitted by the following organs was evaluated: brain, liver, spleen, kidneys, lungs, heart, intestine, adipose tissue, tumor tissue (e.g. see
As shown in
The IV injection in rats of 50 μL of an extracellular vesicle preparation obtained according to the present invention from an oncological patient and loaded with gadoteric acid showed a remarkable selectivity after 24 h after inoculation for LL2 tumor tissues (as shown in
Assays for the incorporation of antibodies (
In particular, for the assay in
For the assay in
A xenograft derived from tumor tissue of the same patient from whose plasma the EVs were obtained was used for the test. Xenotransplantation is a study model where tissue or cells from a patient's tumor are implanted and allowed to proliferate in an immunodeficient rat, which is essential to prevent transplant rejection and promote its rooting. In detail, a volume of about 1 cm3 was taken from each selected nodule, cut into small fragments (about 3 mm3), then subcutaneously inoculated into the sides of SCID immunodeficient rats to an inoculated volume of about 100 mm3. When the tumor reached a size of 300-400 mm3 a basal autofluorescence emission acquisition was performed to eliminate the “background noise”; the acquisition was obtained through gaseous anesthesia with diisoflurane and by measuring the emission of fluorescence (ex:788 nm, em.: 813 nm) for 1 second of exposure through the IVIS Spectrum device (PerkinElmer, Waltham, Mass., US). The images obtained are the basal fluorescence emitted by the animals (autofluorescence) in the ICG fluorescence spectrum. The overlapping of reflected light and fluorescent images was done with Living Image Software 4.8 (PerkinElmer). The EVs isolated from the plasma of oncological patients were loaded as a therapeutic drug and with ICG as a diagnostic drug (EV1), as described in the procedure described above. 108 EV1 were injected intravenously and 24 hours after injection fluorescence emitted in vivo from mice (in vivo imaging) was acquired, as described above. At the end of the acquisition, the rats were sacrificed by cervical dislocation, dissected, and the fluorescence emitted by the following organs was evaluated: brain, liver, spleen, kidneys, lungs, heart, intestine, adipose tissue, tumor tissue (e.g. see
With the owners' informed consent, EVs were isolated from the blood of two dogs weighing 28 and 27 kg, admitted to a veterinary clinic for mastocytoma (i.e. superficial tumor originating from connective tissue mast cells) and mammary cancer, respectively. After isolation using the same procedure as described for EVs from human patient blood, the EVs were loaded with ICG as the diagnostic drug (EV1) as described in the procedure described above. The EVis were then intravenously re-infused to the donor dog 24 hours prior to surgery. In detail, 2-4*106 EV/Kg were suspended in 10 ml of saline solution and injected at a rate of 1 ml/min. Immediately after surgical removal, the tumors were subjected to an imaging procedure using IVIS Lumina II Quantitative Fluorescent and Bioluminescent Imaging (PerkinElmer, Waltham, Mass., US), then fixed and included in paraffin for confirmation by NIR fluorescence microscopy and histology. Ex vivo imaging with the IVIS instrument revealed the presence of a fluorescent signal in the NIR spectrum only in the tumor area (
From the foregoing description, the advantages offered by the formulations of the invention will be apparent to the person skilled in the field.
In particular, as far as diagnostic applications are concerned, these can be:
In intraoperative application, vesicles prepared according to this invention have the advantage of allowing a primary tumor or metastases to be visualized, delineating the margins of the tumor compared to healthy tissue and allowing the surgeon to operate precisely.
In imaging applications, the considered techniques most appropriate by the person skilled in the field can be used during preliminary diagnosis or treatment with a pharmacological or surgical drug.
In diagnostic imaging applications, moreover, the extracellular vesicles of the present invention allow the transport of a large amount of diagnostic drug due to their large volume; advantageously, this may lead to an increase in the sensitivity of the diagnostic method.
More in general, by virtue of the extracellular vesicles proposed by the present invention, drugs, represented by small molecules or biological agents, can be selectively delivered to the tumor target, thereby increasing the effectiveness of a therapeutic protocol and reducing its side effects.
By virtue of their size, the vesicles are very well suited to deliver large-sized drugs, large quantities of small-sized drugs, such as fluorescent molecules, chemical elements, such as gadolinium, radioactive molecules, such as 18FDG, or they can accommodate large-size molecules, such as antibodies, oligonucleotides or whole viruses.
In addition, it is worth noting that the extracellular vesicle acts as a shell protecting the drug from the action of metabolism and/or degradation performed by the human body, as well as protecting non-target tissues from the action of the drug itself; such an aspect is particularly important for biological drugs.
The process described for the preparation of the vesicles of the present invention loaded with drugs having therapeutic and/or diagnostic action comprises simple and fast steps and is, on the whole, a method which can be applied and integrated within the procedures of even the smallest hospital centers.
Furthermore, the use of autologous extracellular vesicles provides ample assurance of the absence of any rejection caused by incompatibility with host tissues.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102019000007785 | May 2019 | IT | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2020/055113 | 5/29/2020 | WO | 00 |
