Tumor Radiosensitization by Gene Electrotransfer-Mediated Double Targeting of Tumor Vasculature.

Targeting the tumor vasculature through specific endothelial cell markers involved in different signaling pathways represents a promising tool for tumor radiosensitization. Two prominent targets are endoglin (CD105), a transforming growth factor ß co-receptor, and the melanoma cell adhesion molecule (CD1046), present also on many tumors. In our recent in vitro study, we constructed and evaluated a plasmid for simultaneous silencing of these two targets. In the current study, our aim was to explore the therapeutic potential of gene electrotransfer-mediated delivery of this new plasmid in vivo, and to elucidate the effects of combined therapy with tumor irradiation. The antitumor effect was evaluated by determination of tumor growth delay and proportion of tumor free mice in the syngeneic murine mammary adenocarcinoma tumor model TS/A. Histological analysis of tumors (vascularization, proliferation, hypoxia, necrosis, apoptosis and infiltration of immune cells) was performed to evaluate the therapeutic mechanisms. Additionally, potential activation of the immune response was evaluated by determining the induction of DNA sensor STING and selected pro-inflammatory cytokines using qRT-PCR. The results point to a significant radiosensitization and a good therapeutic potential of this gene therapy approach in an otherwise radioresistant and immunologically cold TS/A tumor model, making it a promising novel treatment modality for a wide range of tumors.

Gene Immunotherapy of Colon Carcinoma with IL-2 and IL-12 Using Gene Electrotransfer.

Gene immunotherapy has become an important approach in the treatment of cancer. One example is the introduction of genes encoding immunostimulatory cytokines, such as interleukin 2 and interleukin 12, which stimulate immune cells in tumours. The aim of our study was to determine the effects of gene electrotransfer of plasmids encoding interleukin 2 and interleukin 12 individually and in combination in the CT26 murine colon carcinoma cell line in mice. In the in vitro experiment, the pulse protocol that resulted in the highest expression of IL-2 and IL-12 mRNA and proteins was used for the in vivo part. In vivo, tumour growth delay and also complete response were observed in the group treated with the plasmid combination. Compared to the control group, the highest levels of various immunostimulatory cytokines and increased immune infiltration were observed in the combination group. Long-term anti-tumour immunity was observed in the combination group after tumour re-challenge. In conclusion, our combination therapy efficiently eradicated CT26 colon carcinoma in mice and also generated strong anti-tumour immune memory.

Evaluation of a Novel Plasmid for Simultaneous Gene Electrotransfer-Mediated Silencing of CD105 and CD146 in Combination with Irradiation.

Targeting tumor vasculature through specific endothelial cell markers represents a promising approach for cancer treatment. Here our aim was to construct an antibiotic resistance gene-free plasmid encoding shRNAs to simultaneously target two endothelial cell markers, CD105 and CD146, and to test its functionality and therapeutic potential in vitro when delivered by gene electrotransfer (GET) and combined with irradiation (IR). Functionality of the plasmid was evaluated by determining the silencing of the targeted genes using qRT-PCR. Antiproliferative and antiangiogenic effects were determined by the cytotoxicity assay tube formation assay and wound healing assay in murine endothelial cells 2H-11. The functionality of the plasmid construct was also evaluated in malignant melanoma tumor cell line B16F10. Additionally, potential activation of immune response was measured by induction of DNA sensor STING and proinflammatory cytokines by qRT-PCR in endothelial cells 2H-11. We demonstrated that the plasmid construction was successful and can efficiently silence the expression of the two targeted genes. As a consequence of silencing, reduced migration rate and angiogenic potential was confirmed in 2H-11 endothelial cells. Furthermore, induction of DNA sensor STING and proinflammatory cytokines were determined, which could add to the therapeutic effectiveness when used in vivo. To conclude, we successfully constructed a novel plasmid DNA with two shRNAs, which holds a great promise for further in vivo testing.

How Cancer Cells Invade Bladder Epithelium and Form Tumors: The Mouse Bladder Tumor Model as a Model of Tumor Recurrence in Patients.

Non-muscle-invasive bladder cancer is the most common form of bladder cancer. The main problem in managing bladder tumors is the high recurrence after the transurethral resection of bladder tumors (TURBT). Our study aimed to examine the fate of intravesically applied cancer cells as the implantation of cancer cells after TURBT is thought to be a cause of tumor recurrence. We established an orthotopic mouse bladder tumor model with MB49-GFP cancer cells and traced them during the first three days to define their location and contacts with normal urothelial cells. Data were obtained by Western blot, immunolabeling, and light and electron microscopy. We showed that within the first two hours, applied cancer cells adhered to the traumatized epithelium by cell projections containing α3ß1 integrin on their tips. Cancer cells then migrated through the epithelium and on day 3, they reached the basal lamina or even penetrated it. In established bladder tumors, E-cadherin and desmoplakin 1/2 were shown as feasible immunohistochemical markers of tumor margins based on the immunolabeling of various junctional proteins. Altogether, these results for the first time illustrate cancer cell implantation in vivo mimicking cellular events of tumor recurrence in bladder cancer patients.

Antitumor in situ vaccination effect of TNFα and IL-12 plasmid DNA electrotransfer in a murine melanoma model.

Gene electrotransfer (GET) is one of the most efficient non-viral gene therapy approaches for the localized transfer of multiple genes into tumors in vivo; therefore, it is especially promising for delivering different cytokines that are toxic if administered systemically. In this study, we used concomitant intratumoral GET of two cytokines: tumor necrosis factor alpha (TNFα), a potent cytotoxic cytokine to induce in situ vaccination, and interleukin 12 (IL-12), an immunostimulatory cytokine to boost the primed local immune response into a systemic one. After performing GET in murine melanoma tumors, both TNFα and IL-12 mRNA levels were significantly increased, which resulted in a pronounced delay in tumor growth of 27 days and a prolonged survival time of mice. An antitumor immune response was confirmed by extensive infiltration of immune cells in the tumor site, and expansion of the effector immune cells in the sentinel lymph nodes. Furthermore, the effect of in situ vaccination was indicated by the presence of vitiligo localized to the treatment area and resistance of the mice to secondary challenge with tumor cells. Intratumoral GET of two cytokines, one for in situ vaccination and one for an immune boost, proved feasible and effective in eliciting a potent and durable antitumor response; therefore, further studies of this approach are warranted.

Inhibition of the Innate Immune Receptors for Foreign DNA Sensing Improves Transfection Efficiency of Gene Electrotransfer in Melanoma B16F10 Cells.

Gene electrotransfer upregulate DNA pattern recognition receptors or DNA sensors, which are part of the innate immune system. In this study, we tested if addition of the cocktail of innate immune system inhibitors to the cells during gene electrotransfer (GET) can increase transfection efficiency and cell survival. The results indicate that this cocktail can decrease cytosolic DNA sensors expression after GET, and consequently increase cell survival and transfection efficiency in B16 cells, but only in highly metastatic B16F10 subtype. We demonstrated that DNA sensors expression during the transfection methods needs to be downregulated if higher transfection efficiency and better cells' survival is needed. The inhibition of the receptors of the innate immune system can improve the transfection efficiency also for GET of malignant melanoma B16 cells, but only of highly metastatic subtype.

Adipose tissue stem cell-derived hepatic progenies as an in vitro model for genotoxicity testing.

The problem of the currently used routine genotoxicity tests is relatively low predictivity of in vitro tests for in vivo genotoxicity and carcinogenicity. An important reason is considered to be inadequate expression of xenobiotic-metabolizing enzymes in indicator cell lines. The aim of our study was to generate metabolically active differentiated hepatic progenies (hDHP) from human adipose tissue-derived mesenchymal stem cells (hASC) for genotoxicity testing. hDHP, generated using a three-step hepatic differentiation procedure, expressed hepatic properties such as glycogen storage and albumin secretion. The results of the comet assay demonstrated comparable sensitivity of hASC and hDHP to detect DNA damage induced by a direct acting genotoxic agent tert-butylhydroperoxide. Exposure to model indirect acting genotoxins benzo(a)pyrene, aflatoxin B1, and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine did not induce DNA damage in hASC, while hDHP cells detected DNA damage induced by benzo(a)pyrene and aflatoxin B1, indicating their metabolic activity. The gene and protein expression analysis confirmed the presence of key enzymes involved in metabolism of the three genotoxins in hDHP cells. Moreover, the exposure of hDHP to the model pro-carcinogens altered the expression of selected metabolic genes. hDHP were further immortalized with hTERT transfection, resulting in a stable cell line that can be matured to metabolically active hDHP ready for genotoxicity testing in only 2 weeks. The advantage of these immortalized cells is their prolonged replicative life span and consequently limitless supply of hDHP cells. We conclude that hDHP cells have a great potential for the application in the routine genotoxicity testing and are therefore worth further investigations.

Polymer-Mediated Delivery of siRNAs to Hepatocellular Carcinoma: Variables Affecting Specificity and Effectiveness.

Despite the advances in anticancer therapies, their effectiveness for many human tumors is still far from being optimal. Significant improvements in treatment efficacy can come from the enhancement of drug specificity. This goal may be achieved by combining the use of therapeutic molecules with tumor specific effects and delivery carriers with tumor targeting ability. In this regard, nucleic acid-based drug (NABD) and particularly small interfering RNAs (siRNAs), are attractive molecules due to the possibility to be engineered to target specific tumor genes. On the other hand, polymeric-based delivery systems are emerging as versatile carriers to generate tumor-targeted delivery systems. Here we will focus on the most recent findings in the selection of siRNA/polymeric targeted delivery systems for hepatocellular carcinoma (HCC), a human tumor for which currently available therapeutic approaches are poorly effective. In addition, we will discuss the most attracting and, in our opinion, promising siRNA-polymer combinations for HCC in relation to the biological features of HCC tissue. Attention will be also put on the mathematical description of the mechanisms ruling siRNA-carrier delivery, this being an important aspect to improve effectiveness reducing the experimental work.

Tailor-made fibroblast-specific and antibiotic-free interleukin 12 plasmid for gene electrotransfer-mediated cancer immunotherapy.

Electrotransfer mediated delivery of interleukin-12 (IL-12) gene, encoded on a plasmid vector, has already been demonstrated to have a potent antitumor efficacy and great potential for clinical application. In the present study, our aim was to construct an optimized IL-12-encoding plasmid that is safe from the regulatory point of view. In light of previous studies demonstrating that IL-12 should be released in a tumor localized manner for optimal efficacy, the strong ubiquitous promoter was replaced with a weak endogenous promoter of the collagen 2 gene, which is specific for fibroblasts. Next, to comply with increasing regulatory demands for clinically used plasmids, the expression cassette was cloned in a plasmid lacking the antibiotic resistance gene. The constructed fibroblast-specific and antibiotic-free IL-12 plasmid was demonstrated to support low IL-12 expression after gene electrotransfer in selected cell lines. Furthermore, the removal of antibiotic resistance did not affect the plasmid expression profile and lowered its cytotoxicity. With optimal IL-12 expression and minimal transgene non-specific effects, i.e., low cytotoxicity, the constructed plasmid could be especially valuable for different modern immunological approaches to achieve localized boosting of the host's immune system.

Gene Electrotransfer of Plasmid-Encoding IL-12 Recruits the M1 Macrophages and Antigen-Presenting Cells Inducing the Eradication of Aggressive B16F10 Murine Melanoma.

Cancer immunotherapy is currently one of the leading approaches in cancer treatment. Gene electrotransfer of plasmids encoding interleukin 12 (IL-12) into the cells leads to the production of IL-12, which drives immune cell polarization to an antitumoral response. One of the cell types that shows great promise in targeting tumor cells under the influence of IL-12 cytokine milieu is that of macrophages. Therefore, the aim of this study was to evaluate gene electrotransfer of antibiotic resistance-free plasmid DNA-encoding murine IL-12 (mIL-12) in mice bearing aggressive B16F10 murine melanoma. IL-12 electrotransfer resulted in the complete long-term eradication of the tumors. Serum mIL-12 and murine interferon γ (mIFNγ) were increased after IL-12 gene electrotransfer. Further on, hematoxylin and eosin (HE) staining showed increased infiltration of immune cells that lasted from day 4 until day 14. Immunohistochemistry (IHC) staining of F4/80, MHCII, and CD11c showed higher positive staining in the IL-12 gene electrotransfer group than in the control groups. Immune cell infiltration into the tumors and the high density of MHCII- and CD11c-positive cells suggest an antitumor polarization of macrophages and the presence of antigen-presenting cells that contributes to the important antitumor effectiveness of IL-12.

Electrotransfer of plasmid DNA radiosensitizes B16F10 tumors through activation of immune response.

BACKGROUND: Tumor irradiation combined with adjuvant treatments, either vascular targeted or immunomodulatory, is under intense investigation. Gene electrotransfer of therapeutic genes is one of these approaches. The aim of this study was to determine, whether gene electrotransfer of plasmid encoding shRNA for silencing endoglin, with vascular targeted effectiveness, can radiosensitize melanoma B16F10 tumors. MATERIALS AND METHODS: The murine melanoma B16F10 tumors, growing on the back of C57Bl/6 mice, were treated by triple gene electrotransfer and irradiation. The antitumor effect was evaluated by determination of tumor growth delay and proportion of tumor free mice. Furthermore, histological analysis of tumors (necrosis, apoptosis, proliferation, vascularization, presence of hypoxia and infiltration of immune cells,) was used to evaluate the therapeutic mechanisms. RESULTS: Gene electrotransfer of plasmid silencing endoglin predominantly indicated vascular targeted effects of the therapy, since significant tumor growth delay and 44% of tumor free mice were obtained. In addition, irradiation had minor effects on radioresistant melanoma, with 11% of mice tumor free. The combined treatment resulted in excellent effectiveness with 88% of mice tumor free, with more than half resistant to secondary tumor challenge, which was observed also with the plasmid devoid of the therapeutic gene. Histological analysis of tumors in the combined treatment group, demonstrated similar mode of action of the gene electrotransfer of plasmid encoding shRNA for silencing endoglin and devoid of it, both through the induction of an immune response. CONCLUSIONS: The results of this study indicate that irradiation can in radioresistant melanoma tumors, by release of tumor associated antigens, serve as activator of the immune response, besides directly affecting tumor cells and vasculature. The primed antitumor immune response can be further boosted by gene electrotransfer of plasmid, regardless of presence of the therapeutic gene, which was confirmed by the high radiosensitization, resulting in prolonged tumor growth delay and 89% of tumor free mice that were up to 63% resistant to secondary challenge of tumor. In addition, gene electrotransfer of therapeutic plasmid for silencing endoglin has also a direct effect on tumor vasculature and tumors cells; however in combination with radiotherapy this effect was masked by pronounced immune response.

Electrochemotherapy of tumors as in situ vaccination boosted by immunogene electrotransfer.

Electroporation is a platform technology for drug and gene delivery. When applied to cell in vitro or tissues in vivo, it leads to an increase in membrane permeability for molecules which otherwise cannot enter the cell (e.g., siRNA, plasmid DNA, and some chemotherapeutic drugs). The therapeutic effectiveness of delivered chemotherapeutics or nucleic acids depends greatly on their successful and efficient delivery to the target tissue. Therefore, the understanding of different principles of drug and gene delivery is necessary and needs to be taken into account according to the specificity of their delivery to tumors and/or normal tissues. Based on the current knowledge, electrochemotherapy (a combination of drug and electric pulses) is used for tumor treatment and has shown great potential. Its local effectiveness is up to 80 % of local tumor control, however, without noticeable effect on metastases. In an attempt to increase systemic antitumor effectiveness of electrochemotherapy, electrotransfer of genes with immunomodulatory effect (immunogene electrotransfer) could be used as adjuvant treatment. Since electrochemotherapy can induce immunogenic cell death, adjuvant immunogene electrotransfer to peritumoral tissue could lead to locoregional effect as well as the abscopal effect on distant untreated metastases. Therefore, we propose a combination of electrochemotherapy with peritumoral IL-12 electrotransfer, as a proof of principle, using electrochemotherapy boosted with immunogene electrotransfer as in situ vaccination for successful tumor treatment.

Improved Specificity of Gene Electrotransfer to Skin Using pDNA Under the Control of Collagen Tissue-Specific Promoter.

In order to ensure safe, efficient and controlled gene delivery to skin, the improvement of delivery methods together with proper design of DNA is required. Non-viral delivery methods, such as gene electrotransfer, and the design of tissue-specific promoters are promising tools to ensure the safety of gene delivery to the skin. In the scope of our study, we evaluated a novel skin-specific plasmid DNA with collagen (COL) promoter, delivered to skin cells and skin tissue by gene electrotransfer. In vitro, we determined the specificity of the COL promoter in fibroblast cells. The specific expression under the control of COL promoter was obtained for the reporter gene DsRed as well as for therapeutic gene encoding cytokine IL-12. In vivo, the plasmid with COL promoter encoding the reporter gene DsRed was efficiently transfected to mouse skin. It resulted in the notable and controlled manner, however, in lower and shorter expression, compared to that obtained with ubiquitous promoter. The concentration of the IL-12 in the skin after the in vivo transfection of plasmid with COL promoter was in the same range as after the treatment in control conditions (injection of distilled water followed by the application of electric pulses). Furthermore, this gene delivery was local, restricted to the skin, without any evident systemic shedding of IL-12. Such specific targeting of skin cells, observed with tissue-specific COL promoter, would improve the effectiveness and safety of cutaneous gene therapies and DNA vaccines.

Gene Electrotransfer of Canine Interleukin 12 into Canine Melanoma Cell Lines.

A gene electrotransfer (GET) of interleukin 12 (IL-12) had already given good results when treating tumors in human and veterinary clinical trials. So far, plasmids used in veterinary clinical studies encoded a human or a feline IL-12 and an ampicillin resistance gene, which is not recommended by the regulatory agencies to be used in clinical trials. Therefore, the aim of the current study was to construct the plasmid encoding a canine IL-12 with kanamycin antibiotic resistance gene that could be used in veterinary clinical oncology. The validation of the newly constructed plasmid was carried out on canine malignant melanoma cells, which have not been used in GET studies so far, and on human malignant melanoma cells. Canine and human malignant melanoma cell lines were transfected with plasmid encoding enhanced green fluorescence protein at different pulse parameter conditions to determine the transfection efficiency and cell survival. The IL-12 expression of the most suitable conditions for GET of the plasmid encoding canine IL-12 was determined at mRNA level by the qRT-PCR and at protein level with the ELISpot assay. The obtained results showed that the newly constructed plasmid encoding canine IL-12 had similar or even higher expression capacity than the plasmid encoding human IL-12. Therefore, it represents a promising therapeutic plasmid for further IL-12 gene therapy in clinical studies for spontaneous canine tumors. Additionally, it also meets the main regulatory agencies' (FDA and EMA) criteria.

Adjuvant TNF-α therapy to electrochemotherapy with intravenous cisplatin in murine sarcoma exerts synergistic antitumor effectiveness.

BACKGROUND: Electrochemotherapy is a tumour ablation modality, based on electroporation of the cell membrane, allowing non-permeant anticancer drugs to enter the cell, thus augmenting their cytotoxicity by orders of magnitude. In preclinical studies, bleomycin and cisplatin proved to be the most suitable for clinical use. Intravenous administration of cisplatin for electrochemotherapy is still not widely accepted in the clinics, presumably due to its lower antitumor effectiveness, but adjuvant therapy by immunomodulatory or vascular-targeting agents could provide a way for its potentiation. Hence, the aim of the present study was to explore the possibility of adjuvant tumour necrosis factor α (TNF-α) therapy to potentiate antitumor effectiveness of electrochemotherapy with intravenous cisplatin administration in murine sarcoma. MATERIALS AND METHODS: In vivo study was designed to evaluate the effect of TNF-α applied before or after the electrochemotherapy and to evaluate the effect of adjuvant TNF-α on electrochemotherapy with different cisplatin doses. RESULTS: A synergistic interaction between TNF-α and electrochemotherapy was observed. Administration of TNF-α before the electrochemotherapy resulted in longer tumour growth delay and increased tumour curability, and was significantly more effective than TNF-α administration after the electrochemotherapy. Tumour analysis revealed increased platinum content in tumours, TNF-α induced blood vessel damage and increased tumour necrosis after combination of TNF-α and electrochemotherapy, indicating an anti-vascular action of TNF-α. In addition, immunomodulatory effect might have contributed to curability rate of the tumours. CONCLUSION: Adjuvant intratumoural TNF-α therapy synergistically contributes to electrochemotherapy with intravenous cisplatin administration. Due to its potentiation at all doses of cisplatin, the combined treatment is predicted to be effective also in tumours, where the drug concentration is suboptimal or in bigger tumours, where electrochemotherapy with intravenous cisplatin is not expected to be sufficiently effective.

Immunospot Assessment of T-Cell Responses in Preclinical Tumor Models with Undefined Target Antigens.

Assessment of functional tumor-specific T-cell responses in preclinical tumor models represents an important tool for successful translation of new immunotherapies to clinics. Usually, it requires a known tumor antigen target. Here, we describe the method to detect tumor-specific T cell after immunotherapies without a known antigen. Splenocytes, lymph node immune cells, or PBMCs are isolated from treated mice and stimulated with relevant tumor cells ex vivo before immunospot analysis of Granzyme B and interferon γ-positive T cells. The method is especially valuable for monitoring tumor-specific T cells after vaccination with various whole tumor vaccines or after in situ vaccination and other antigen agnostic immunotherapies, where no specific antigens are used.

Interleukins and interferons in mesenchymal stromal stem cell-based gene therapy of cancer.

The tumor microenvironment is importantly shaped by various cytokines, where interleukins (ILs) and interferons (IFNs) shape the balance of immune activity within tumor niche and associated lymphoid organs. Their importance in activation and tuning of both innate and adaptive immune responses prompted their use in several clinical trials, albeit with limited therapeutic efficacy and risk of toxicity due to systemic administration. Increasing preclinical evidence suggests that local delivery of ILs and IFNs could significantly increase their effectiveness, while simultaneously attenuate the known side effects and issues related to their biological activity. A prominent way to achieve this is to use cell-based delivery vehicles. For this purpose, mesenchymal stromal stem cells (MSCs) are considered an almost ideal candidate. Namely, MSCs can be obtained in large quantities and from obtainable sources (e.g. umbilical cord or adipose tissue), their ex vivo expansion is relatively straightforward compared to other cell types and they possess very low immunogenicity making them suitable for allogeneic use. Importantly, MSCs have shown an intrinsic capacity to respond to tumor-directed chemotaxis. This review provides a focused and detailed discussion on MSC-based gene therapy using ILs and IFNs, engineering techniques and insights on potential future advancements.

Establishment of Mouse Orthotopic Urinary Bladder Tumor Model and Its Analysis by Light and Electron Microscopy.

Mouse tumor models are an important tool in cancer research, and the orthotopic cancer cell transplantation model is the most widely used among them. Methods for establishing tumor models may differ in many ways, including the selection of cancer cell lines and the type of urinary bladder pretreatment. Here, we describe our mouse orthotopic bladder tumor model using a labeled MB49 urothelial cancer cell line and chemical pretreatment with the cationic polypeptide poly-L-lysine to traumatize the bladder epithelium. Double labeling of MB49 cancer cells by their transduction with GFP and internalization of metal nanoparticles allows the study of their implantation process from the first hours to several days after intravesical injection, as well as the analysis of developed tumors after 3 weeks. Thus, our model provides a comprehensive analysis of the early and late stages of tumor development in the bladder at the light and electron microscopic level.

Preclinical Mouse Metastatic Model Established Through Induced Lung Metastases.

Metastatic disease is the major cause of cancer death, and the lung is one of the most common sites of cancer metastases. To investigate systemic antitumor effects or protective potential of local therapies, mouse models with induced metastases are indispensable in preclinical cancer research. Here, we describe the protocol for the metastatic mouse model established through induced 4T1 mammary carcinoma metastases. With minor prior optimization, it can be applied to other tumor cell lines of interest.

Human Omental Mature Adipocytes used as Paclitaxel Reservoir for Cell-Based Therapy in Ovarian Cancer.

Primary human omental adipocytes and ovarian cancer(OC) cells establish a bidirectional communication in which tumor driven lipolysis is induced in adipocytes and the resulting fatty acids are delivered to cancer cells within the tumor microenvironment. Despite meaningful improvement in the treatment of OC, its efficacy is still limited by hydrophobicity and untargeted effects related to chemotherapeutics. Herein, omental adipocytes are firstly used as a reservoir for paclitaxel, named Living Paclitaxel Bullets (LPB) and secondly benefit from the established dialogue between adipocytes and cancer cells to engineer a drug delivery process that target specifically cancer cells. These results show that mature omental adipocytes can successfully uptake paclitaxel and deliver it to OC cells in a transwell coculture based in vitro model. In addition, the efficacy of this proof-of-concept has been demonstrated in vivo and induces a significant inhibition of tumor growth on a xenograft tumor model. The use of mature adipocytes can be suitable for clinical prospection in a cell-based therapy system, due to their mature and differentiated state, to avoid risks related to uncontrolled cell de novo proliferation capacity after the delivery of the antineoplastic drug as observed with other cell types when employed as drug carriers.