Mesenchymal stem cell-mediated cancer therapy: A dual-targeted strategy of personalized medicine

Current progress in engineered and nano-engineered mesenchymal stem cells for cancer: From mechanisms to therapy

Mesenchymal stem cells (MSCs), as self-renewing multipotent stromal cells, have been considered promising agents for cancer treatment. A large number of studies have demonstrated the valuable properties of MSC-based treatment, such as low immunogenicity and intrinsic tumor-trophic migratory properties. To enhance the potency of MSCs for therapeutic purposes, equipping MSCs with targeted delivery functions using genetic engineering is highly beneficial. Genetically engineered MSCs can express tumor suppressor agents such as pro-apoptotic, anti-proliferative, anti-angiogenic factors and act as ideal delivery vehicles. MSCs can also be loaded with nanoparticle drugs for increased efficacy and externally moderated targeting. Moreover, exosomes secreted by MSCs have important physiological properties, so they can contribute to intercellular communication and transfer cargo into targeted tumor cells. The precise role of genetically modified MSCs in tumor environments is still up for debate, but the beginning of clinical trials has been confirmed by promising results from preclinical investigations of MSC-based gene therapy for a wide range of malignancies. This review highlights the advanced techniques of engineering/nano-engineering and MSC-derived exosomes in tumor-targeted therapy.

The role of KiSS1 gene on the growth and migration of prostate cancer and the underlying molecular mechanisms

Metastatic prostate cancers have a high mortality rate. KiSS1 was originally identified as a metastasis suppressor gene in metastatic melanoma and breast cancer, but its role in prostate cancer has been contradictory. This study was therefore undertaken to investigate the effects of KiSS1 overexpression on the growth and migration of human metastatic prostate cancer cells. We first tested the effect of KiSS1 overexpression on the growth and migration of DU145 human metastatic prostate cancer cells in vitro. DU145 cells were infected with the culture medium of 293T cells, which produce lentivirus particles containing KiSS1. A 2.5-fold increase in proliferation of KiSS1-overexpressing cancer cells was observed, and these cells formed tumor spheroids about 3 times larger than the vector control group. qPCR and immunoblotting revealed the association between increased cell growth and regulation of the PI3K/Akt and cell cycle genes, and also that increases in β-catenin and CD133 contribute to tumor aggregation. KiSS1 overexpression resulted in upregulation of the β-arrestin1/2 and Raf-MEK-ERK-NF-κB pathways via KiSS1R. Moreover, the migration and invasion of KiSS1-overexpressing cells were determined to be faster than the control group, along with 1.6-fold increased metastatic colonization of the KiSS1-overexpressing cancer cells. These were associated to the regulation of EMT gene expressions, such as E-cadherin and N-cadherin, and the upregulation of MMP9. In a xenograft mouse model inoculated with DU145 cells infected GFP or KiSS1 via a lentiviral vector, KiSS1 statistically significantly increased the tumor growth, with upregulation of PCNA and Ki-67 in the tumor tissues. In addition, KiSS1 increased the angiogenic capacity by upregulating VEGF-A and CD31, both in vitro and in vivo. Taken together, our results indicate that KiSS1 not only induces prostate cancer proliferation, but also promotes metastasis by increasing the migration, invasion, and angiogenesis of malignant cells.

Synthetic mRNA-based gene therapy for glioblastoma: TRAIL-mRNA synergistically enhances PTEN-mRNA-based therapy

Glioblastoma (GBM) is characterized as having high molecular heterogeneity and complexity, which can be well revealed by genomic study. A truly effective treatment for GBM should flexibly address its heterogeneities, complexity, and strong drug resistance. This study was performed to explore the effectiveness of an mRNA-based therapeutic strategy using in vitro synthesized PTEN-mRNA and TRAIL-mRNA in tumor cells derived from PTEN-deletion patients. The PTEN gene alterations were revealed by whole-exome sequencing of three paired clinical GBMs and selected as the therapy target. Patient-derived primary glioblastoma stem cells (GBM2) and a DBTRG-cell-derived xenograft were used to detect mRNA's cytotoxicity in vitro and tumor suppression in vivo. Following the successful in vitro synthesis of PTEN-mRNA and TRAIL-mRNA, the combinational treatment of PTEN-mRNA and TRAIL-mRNA significantly suppressed tumor growth compared with treatment with PBS (96.4%), PTEN-mRNA (89.7%), and TRAIL-mRNA (84.5%). The combinational application of PTEN-mRNA and TRAIL-mRNA showed synergistic inhibition of tumor growth, and the JNK pathway might be the major mechanism involved. This study provided a basis for an mRNA-based therapeutic strategy to be developed into an effective patient-tailored treatment for GBM.

MSCs loaded with oncolytic reovirus: migration and in vivo virus delivery potential for evaluating anti-cancer effect in tumor-bearing C57BL/6 mice

Background and aims

Several oncolytic viruses applications have been approved in the clinic or in different phases of clinical trials. However, these methods have some rudimentary problems. Therefore, to enhance the delivery and quality of treatment, considering the advantage of cell carrier-based methods such as Mesenchymal Stem Cells (MSC) have been proposed. This study was designed to evaluate the performance and quality of cancer treatment based on MSCs loaded by oncolytic reovirus in the cancerous C57BL/6 mouse model. Also, we evaluated MSCs migration potency in vitro and in vivo following the oncolytic reovirus infection.

Methods

C57BL/6 mice were inoculated with TC-1 cell lines and tumors were established in the right flank. Mice were systemically treated with reovirus, MSCs-loaded with reovirus, MSCs, and PBS as a control in separated groups. Effects of infected AD-MSCs with reovirus on tumor growth and penetration in the tumor site were monitored. All groups of mice were monitored for two months in order to therapeutic and anticancer potential. After treatments, tumor size alteration and apoptosis rate, as well as cytokine release pattern was assessed.

Results

The results of the current study indicated that the effect of reovirus infection on AD-MSCs is not devastating the migration capacity especially in MOI 1 and 5 while intact cells remain. On the other hand, MSCs play an efficient role as a carrier to deliver oncolytic virus into the tumor site in comparison with systemic administration of reovirus alone. Apoptosis intensity relies on viral titration and passing time. Followed by systemic administration, treatment with oncolytic reovirus-infected AD-MSCs and MSCs alone had shown significant inhibition in tumor growth. Also, treatment by reovirus causes an increase in IFN-γ secretion.

Conclusion

The results of in vitro and in vivo study confirmed the tumor-homing properties of infected AD-MSCs and the significant antitumor activity of this platform. Hence, our results showed that the cell carrier strategy using oncolytic reovirus-loaded AD-MSCs enhanced virus delivery, infiltration, and antitumor activity can be effectively applied in most cancers.

Engineering mesenchymal stem cells: a novel therapeutic approach in breast cancer

Breast cancer is one of the most prevalent and deadliest cancers among women in the world because of its aggressive behaviour and inadequate response to conventional therapies. Cellular and gene therapies based on mesenchymal stem cells (MSCs) represent promising treatment strategies for multiple diseases, such as cancers. MSCs are multipotent adult stem cells with important features for cell therapy, such as tissue homing to injured sites, their differentiation potential, their capacity of secreting plenty of trophic factors, and low immunogenicity. The quite easy isolation of these cells from various types of tissues are associated with no ethical concern when dealing with foetal or embryonic stem cells. The MSCs exhibit both pro and anti-oncogenic properties. However, genetic engineering of MSCs and nanoparticles is being employed as a means to solve some of these problems and improve the antitumor properties of these cells. The tumour-homing ability of MSCs and their exosomes to tumour niches have made them as a promising vector for targeted delivery of therapeutic agents to tumours site. The present study investigated MSCs specifications, pro- and anti-oncogenic properties of MSCs in breast cancer, and reviewed targeted breast cancer therapy via engineered MSCs, likely as potent cellular vehicles.

Mesenchymal stem cell transplantation attenuates growth of chemotherapy treated oral squamous cell carcinoma in an animal model

BACKGROUND

Recent studies have demonstrated mesenchymal stem cell migration toward tumor locations. When applied locally, MSCs interact with the locally residing host cells. The mechanisms behind this are still unclear. We aimed to detect the possible action mechanisms of MSCs on the in vivo growth of primary human oral squamous cell carcinoma.

METHODS

In mouse model of OSSC, chemotherapy with Cisplatin was done beginning from 9 day of tumor visualization. 3 weeks after tumor cell injection cultivated MSCs were administrated in tail vein or directly intra-tumorally. Animals underwent surveillance and afterward were sacrificed. Tumor growth was measured. MSCs biodistribution was assessed with bioluminescent analysis. Tumor tissues were tested morphologically and immunohistochemically for angiogenesis, hypoxia status, and cell apoptosis.

RESULTS

In the group treated with Cisplatin in combination with mesenchymal stem cell injection, the average size of the tumor was 98.9 ± 7.65 mm³ . In the experimental group, tumor tissues were less outlined and the presence of necrotic areas and connective tissue basal layers was detected. Immunohistochemical surveys with CD31 and anti-carbonic anhydrase 9 demonstrated strongly developed micro-vessel structures and small isles of hypoxia in the tumor tissues. TUNEL assay revealed in the same group that tumor tissues were mostly comprised of apoptotic cells. Viable cell communities presented as small isles.

CONCLUSION

The study demonstrates that intra-tumorally injected MSCs, combined with Cisplatin, leads to a minimal hypoxia status and increased apoptotic activity in tumor tissues, compared with the control group. This finding can be explained with better distribution of Cisplatin due to increased angiogenesis.

MicroRNA-4731-5p delivered by AD-mesenchymal stem cells induces cell cycle arrest and apoptosis in glioblastoma

Glioblastoma multiforme (GBM) exhibits the most malignant brain tumor with very poor prognosis. MicroRNAs (miRNAs) are regulatory factors that can downregulate the expression of multiple genes. Several miRNAs acting as tumor-suppressor genes have been identified so far. The delivery of miRNA by mesenchymal stem cell (MSC) due to their ability to specifically target tumors is a new, hopeful therapeutic approach for glioblastoma. The objective of our study is the investigation of the effect of lentivirus-mediated microRNA-4731 (miR-4731) genetic manipulated adipose-derived (AD)-MSC on GBM. The downregulation of miR-4731 in human GBM tumor was detected using the GEO dataset. To evaluate the function of miR-4731, we overexpressed miR-4731 using lentiviral vectors in U-87 and U-251 GBM cell lines. The effects of miR-4731 on cell proliferation and cell cycle of glioma cells were analyzed by wound test and flow-cytometry assay. miR-4731 inhibited the proliferation of GBM cancer cells. Coculturing was used to study the antiproliferative effect of miR-4731-AD-MSCs on GBM cell lines. Direct and indirect coculture of GBM cell lines with miR-4731-AD-MSCs induced cell cycle arrest and apoptosis. Our findings suggest that AD-MSCs expressing miR-4731 have favorable antitumor characteristics and should be further explored in future glioma therapy.

In Vitro Assessment of Cytokine Expression Profile of MCF-7 Cells in Response to hWJ-MSCs Secretome

Purpose: Several attempts have been made to identify the mechanisms by which mesenchymal stem cells (MSCs)-derived secretome exert anti-tumor or tumorigenic effects, but still further investigations are needed to explore this subject. Thus, in this study we want to examine the expression of different cytokines in secretome of hWJ-MSCs and their effects on cytokine expression profile of the MCF-7 tumor cells.

Methods: The hWJ-MSCs were isolated and characterized according to the International Society for Cellular Therapy criteria. Then, secretome of hWJ-MSCs was collected and freeze-dried, and 20 mg/mL of the freeze-dried secretome was used to treat MCF-7 cancer cells for 48 hours. Afterwards, the expression levels of 12 cytokines including IL-1a, IL-1b, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IL-17A, TNFα, IFNγ and GM-CSF in secretome of hWJ-MSCs alone as well as in supernatant of tumor cells before and after treatment with hWJ-MSCs secretome were evaluated.

Results: Our results indicate that MCF-7 cells express significant amount of IL-6 and IL-8. Moreover, significant amounts of IL-1a, IL-1b, IL-8, IL-6 and GM-CSF were detected in secretome of hWJ-MSCs. Furthermore, IL-1a, IL-2 and IL-4 were expressed significantly by MCF-7 cells after their treatment with hWJ-MSCs-derived secretome.

Conclusion: According to our findings, the hWJ-MSCs derived secretome contains different cytokines which can exert either anti-tumor or tumorigenic effects.

The application of mRNA-based gene transfer in mesenchymal stem cell-mediated cytotoxicity of glioma cells

Since the tumor-oriented homing capacity of mesenchymal stem cells (MSCs) was discovered, MSCs have attracted great interest in the research field of cancer therapy mainly focused on their use as carries for anticancer agents. Differing from DNA-based vectors, the use of mRNA-based antituor gene delivery benefits from readily transfection and mutagenesis-free. However, it is essential to verify if mRNA transfection interferes with MSCs' tropism and their antitumor properties. TRAIL- and PTEN-mRNAs were synthesized and studied in an in vitro model of MSC-mediated indirect co-culture with DBTRG human glioma cells. The expression of TRAIL and PTEN in transfected MSCs was verified by immunoblotting analysis, and the migration ability of MSCs after anticancer gene transfection was demonstrated using transwell co-cultures. The viability of DBTRG cells was determined with bioluminescence, live/dead staining and real time cell analyzer. An in vivo model of DBTRG cell-derived xenografted tumors was used to verify the antitumor effects of TRAIL- and PTEN-engineered MSCs. With regard to the effect of mRNA transfection on MSCs' migration toward glioma cells, an enhanced migration rate was observed with MSCs transfected with all tested mRNAs compared to non-transfected MSCs (p<0.05). TRAIL- and PTEN-mRNA-induced cytotoxicity of DBTRG glioma cells was proportionally correlated with the ratio of conditioned medium from transfected MSCs. A synergistic action of TRAIL and PTEN was demonstrated in the current co-culture model. The immunoblotting analysis revealed the apoptotic nature of the cells death in the present study. The growth of the xenografted tumors was significantly inhibited by the application of MSCPTEN or MSCTRAIL/PTEN on day 14 and MSCTRAIL on day 28 (p<0.05). The results suggested that anticancer gene-bearing mRNAs synthesized in vitro are capable of being applied for MSC-mediated anticancer modality. This study provides an experimental base for further clinical anticancer studies using synthesized mRNAs.

Antitumor activity of yulangsan polysacchrides in mice bearing S180 sarcoma tumors

Sarcoma is one of the most prevalent pediatric tumors and the therapeutic role of chemotherapy has yet to be elucidated. It has been reported that extracts of Longyanshen (Yulangsan) may enhance the sensitivity of drug-resistant cancer cell lines, and improve the immune dysfunction induced by cyclophosphamide (CTX) in mice. The present in vivo study investigated the antitumor effects of Yulangsan polysaccharides (YLSPS) and their interaction with CTX in murine sarcoma 180 (S180)-bearing mice. Immunohistochemistry was used to detect the expression of apoptosis-related proteins. The ultrastructure of sarcoma cells was examined by transmission electron microscopy and the tumor growth rate was determined by measuring the tumor weight. A dose-dependent inhibition of sarcoma growth was observed in S180-bearing mice following administration of YLSPS. In combination with CTX, an additive antitumor effect was obtained, which was accompanied by amelioration of immune function. YLSPS also potentiated the tumor suppression effect of CTX while avoiding cytotoxicity against immune cells. YLSPS inhibited sarcoma growth in S180-bearing mice through the induction of apoptosis in S180 sarcoma cells. YLSPS also attenuated CTX-induced cytotoxicity to the immune system while potentiating the tumor suppression effect. These results provide additional information regarding combination therapy with YLSPS and chemotherapy for the treatment of sarcoma.

Immunoproapoptotic molecule scFv-Fdt-tBid modified mesenchymal stem cells for prostate cancer dual-targeted therapy

Highly efficient target therapy is urgently needed for prostate cancer with overexpression of γ-seminoprotein (γ-SM). Recent studies indicated that mesenchymal stem cells (MSCs) are attractive candidate for cell-based, targeted therapy due to their tumor tropism. Here we designed a dual-target therapeutic system in which MSCs were engineered to produce and deliver scFv-Fdt-tBid, a novel γ-SM-targeted immunoproapoptotic molecule. Such engineered MSCs (MSC.scFv-Fdt-tBid) would home to tumor sites and release the fusion protein to induce the apoptosis of prostate cancer cells. Our data demonstrated that scFv-Fdt-tBid showed a selective, potent and dose-dependent inhibition for γ-SM-positive cells (LNCaP, C4-2, 22Rv1) rather than γ-SM-negative cells and MSCs. Importantly, MSC.scFv-Fdt-tBid caused cell death through an apoptosis-dependent manner. Further, the tropism of MSC.scFv-Fdt-tBid to prostate cancer was verified both in vitro and in vivo. Finally, the in vivo experiments demonstrated that MSC.scFv-Fdt-tBid significantly inhibited γ-SM-positive tumor growth without toxic side effects. Collectively, this study represented a novel immunoproapoptotic molecule scFv-Fdt-tBid for γ-SM-positive tumors and demonstrated the therapeutic efficiency and safety of scFv-Fdt-tBid-modified MSCs against prostate cancers.

Controlled Secretion of the Anticancer Protein MDA-7 from Engineered Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) have been explored as a "live" carrier of cytokines for targeted cancer therapy, but, in earlier reports in the literature, the secretion process of therapeutic cytokines was not regulated. The purpose of this study was to generate MSCs to conditionally secrete the melanoma differentiation-associated gene-7 (MDA-7) tumor-suppressor protein. To control the secretion of MDA-7 from MSCs, a well-established tetracycline-controlled transcriptional activation system was incorporated into MDA-7 plasmid. MDA-7 gene expression was induced in the engineered MSCs only in the presence of doxycycline, as characterized by quantitative reverse transcription (qRT)-PCR. Enzyme-linked immunosorbent assay (ELISA) also revealed that the MDA-7 protein was secreted from the engineered MSCs only after the cells had been exposed to doxycycline. Both recombinant human MDA-7 protein and the conditioned medium from the engineered MSCs in the presence of doxycycline significantly inhibited tube formation of human umbilical vascular endothelial cells (HUVECs), indicating that our system could be used for targeted, antiangiogenic therapy. Overall, this study provides useful information on the potential use of engineered MSCs for the controlled secretion of therapeutic proteins, in this case MDA-7, for targeted cancer therapy.

PTEN-mRNA engineered mesenchymal stem cell-mediated cytotoxic effects on U251 glioma cells

Mesenchymal stem cells (MSCs) have been considered to have potential as ideal carriers for the delivery of anticancer agents since the capacity for tumor-oriented migration and integration was identified. In contrast to DNA-based vectors, mRNA synthesized in vitro may be readily transfected and is mutagenesis-free. The present study was performed in order to investigate the effects of phosphatase and tensin homolog (PTEN) mRNA-engineered MSCs on human glioma U251 cells under indirect co-culture conditions. PTEN-bearing mRNA was generated by in vitro transcription and was transfected into MSCs. The expression of PTEN in transfected MSCs was detected by immunoblotting, and the migration ability of MSCs following PTEN-bearing mRNA transfection was verified using Transwell co-cultures. The indirect co-culture was used to determine the effects of PTEN-engineered MSCs on the viability of U251 glioma cells by luminescence and fluorescence microscopy. The synthesized PTEN mRNA was expressed in MSCs, and the expression was highest at 24 h subsequent to transfection. An enhanced migration rate was observed in MSCs transfected with PTEN mRNA compared with non-transfected MSCs (P<0.05). A significant inhibition of U251 cells was observed when the cells were cultured with conditioned medium from PTEN mRNA-engineered MSCs (P<0.05). The results suggested that anticancer gene-bearing mRNA synthesized in vitro is capable of being applied to a MSC-mediated anticancer strategy for the treatment of glioblastoma patients.

Dextran-coated iron oxide nanoparticles turn protumor mesenchymal stem cells (MSCs) into antitumor MSCs

dex-IO NPs can activate the antitumor mechanism (tumor tropism) but inactivate protumor mechanisms to transform protumor MSCs (pT-MSCs) into antitumor MSCs (aT-MSCs).

Genetically engineered mesenchymal stem cell therapy using self-assembling supramolecular hydrogels

Stem cell therapy has attracted a great deal of attention for treating intractable diseases such as cancer, stroke, liver cirrhosis, and ischemia. Especially, mesenchymal stem cells (MSCs) have been widely investigated for therapeutic applications due to the advantageous characteristics of long life-span, facile isolation, rapid proliferation, prolonged transgene expression, hypo-immunogenicity, and tumor tropism. MSCs can exert their therapeutic effects by releasing stress-induced therapeutic molecules after their rapid migration to damaged tissues. Recently, to improve the therapeutic efficacy, genetically engineered MSCs have been developed for therapeutic transgene expression by viral gene transduction and non-viral gene transfection. In general, the number of therapeutic cells for injection should be more than several millions for effective cell therapy. Adequate carriers for the controlled delivery of MSCs can reduce the required cell numbers and extend the duration of therapeutic effect, which provide great benefits for chronic disease patients. In this review, we describe genetic engineering of MSCs, recent progress of self-assembling supramolecular hydrogels, and their applications to cell therapy for intractable diseases and tissue regeneration.

Potential of Mesenchymal Stem Cell based application in Cancer

Stem cell based treatments are being increasingly explored for their possible potential to treat various cancers. Mesenchymal stem cells believed to possess anti-tumor potential and are preferred for their properties like immune privileged nature, ability to migrate to the site of tumor and capability for multilineage differentiation. This tumor tropism property of MSCs could be utilized to deliver anti-tumor biological agents to the site of tumor. In a tumor micro-environment, MSCs are believed to play both, a pro-tumorigenic and an anti-tumorigenic role. However, this is dependent on a host of factors like, types of MSCs, its source, type of cancer cell line under investigation, in vivo or in vitro conditions, factors secreted by MSCs and interactions between MSCs, host's immune cells and cancer cells. Among several cytokines secreted by MSCs, TRAIL (Tumor necrosis factor related apoptosis inducing ligand) is reported to be pro-apoptotic for tumor cells. The MSCs from bone marrow and adipose tissue have been studied quite extensively. Deriving MSCs from sources such as umbilical cord blood and umbilical cord tissue is relatively easier. Umbilical cord tissue preferred for MSC derivation due to their abundant availability. These MSCs believed to up regulate TRAIL expression in MSC-cancer cell co-culture system resulting in induction of apoptosis in cancer cells. However, umbilical cord tissue derived MSCs needs to be studied for expression pattern of TRAIL in a co-culture system. We present a review article on different studies reporting both, pro-tumorigenic and anti-tumorigenic properties of MSCs.

Targeting delivery of lipocalin 2-engineered mesenchymal stem cells to colon cancer in order to inhibit liver metastasis in nude mice

One of the major obstacles in cancer therapy is the lack of anticancer agent specificity to tumor tissues. The strategy of cell-based therapy is a promising therapeutic option for cancer treatment. The specific tumor-oriented migration of mesenchymal stem cells (MSCs) makes them a useful vehicle to deliver anticancer agents. In this study, we genetically manipulated bone marrow-derived mesenchymal stem cells with their lipocalin 2 (Lcn2) in order to inhibit liver metastasis of colon cancer in nude mice. Lcn2 was successfully overexpressed in transfected MSCs. The PCR results of SRY gene confirmed the presence of MSCs in cancer liver tissue. This study showed that Lcn2-engineered MSCs (MSC-Lcn2) not only inhibited liver metastasis of colon cancer but also downregulated the expression of vascular endothelial growth factor (VEGF) in the liver. Overall, MSCs by innate tropism toward cancer cells can deliver the therapeutic agent, Lcn2, and inhibit cancer metastasis. Hence, it could be a new modality for efficient targeted delivery of anticancer agent to liver metastasis.

Nucleofection optimization and in vitro anti-tumourigenic effect of TRAIL-expressing human adipose-derived mesenchymal stromal cells

Background

Tumour homing capacity of engineered human adipose-derived mesenchymal stromal cells (ADMSCs) expressing anti-tumour agents might be the key for a much safer and yet efficient targeted tumour therapy. However, ADMSCs exhibit resistant to most gene transfection techniques and the use of highly efficient viral vectors has several disadvantages primarily concerning safety risk. Here, we optimized the use of highly efficient and safe nucleofection-based transfection using plasmid encoded for TNF-Related Apoptosis Inducing Ligand (TRAIL) into ADMSCs and investigated the potential anti-tumourigenic of TRAIL-expressing ADMSCs (ADMSCs-TRAIL) on selected cancer models in vitro.

Methods

Different concentration of TRAIL-encoded plasmid and ADMSCs were nucleofected and the percentage of fluorescence cells were analyzed to determine the optimal condition. TRAIL protein and mRNA were validated in nucloeofected ADMSCs using ELISA and RT-PCR respectively. Evaluation of TRAIL specific death receptors were performed on both tumours (A549/lung tumour, LN18/glioblastoma and HepG2/hepatocellular carcinoma) and haematological malignant lines (REH/acute lymphocytic leukaemia, K562/chronic myelogenous leukaemia and KMS-28BM/multiple myeloma) using flow cytometry. ADMSCs-TRAIL was subsequently assessed for anti-tumourigenic properties using both proliferation assay (MTS assay) and apoptosis assay (Annexin-V / Propidium Iodide staining).

Results

Nucleofection showed increased total plasmid concentration (2 μg to 8 μg) resulted in significantly higher reporter expression (11.33% to 39.7%) with slight reduction on cells viability (~10%). ADMSCs-TRAIL significantly inhibited ~50% of cell proliferation in LN18, signifying sensitivity of the cell to ADMSCs-TRAIL mediated inhibition. Inhibition of both tumour and malignant lines proliferation by ADMSCs-TRAIL conditioned medium noticed in HepG2, A549 and REH respectively, whereas K562 and KMS-28BM malignant lines exhibit resistant to ADMSCs-TRAIL mediated inhibition. Moreover, we found that native ADMSCs alone were capable of inducing apoptosis in both LN18 and HepG2 tumour lines, despite substantial increased on the percentage of apoptosis by ADMSCs-TRAIL.

Conclusion

ADMSCs-TRAIL selectively inhibit cancer model and markedly induces apoptosis. Through investigation of the specific TRAIL death receptors expression, we saw that the receptors expression did influence the sensitivity of some but not all cancer lines to TRAIL-mediated inhibition. This study provides further insight into the anti-tumourigenic potential of ADMSCs-TRAIL on different cancer models.

Cancer cell-oriented migration of mesenchymal stem cells engineered with an anticancer gene (PTEN): an imaging demonstration

BACKGROUND

Mesenchymal stem cells (MSCs) have been considered to hold great potential as ideal carriers for the delivery of anticancer agents since the discovery of their tumor tropism. This study was performed to demonstrate the effects of phosphatase and tensin homolog (PTEN) engineering on MSCs' capacity for cancer cell-oriented migration.

METHODS

MSCs were engineered with a PTEN-bearing plasmid and the expression was confirmed with Western blotting. A human glioma cell line (DBTRG) was used as the target cell; DBTRG cell-oriented migration of MSCs was monitored with a micro speed photographic system.

RESULTS

The expression of transfected PTEN in MSCs was identified by immunoblotting analysis and confirmed with cell viability assessment of target cells. The DBTRG cell-oriented migration of PTEN-engineered MSCs was demonstrated by a real-time dynamic monitoring system, and a phagocytosis-like action of MSCs was also observed.

CONCLUSION

MSCs maintained their capacity for cancer cell-directed migration after they were engineered with anticancer genes. This study provides the first direct evidence of MSCs' tropism post-anticancer gene engineering.

Tumor necrosis factor-α/CD40 ligand-engineered mesenchymal stem cells greatly enhanced the antitumor immune response and lifespan in mice

The interaction between mesenchymal stem cells (MSCs) and dendritic cells (DCs) affects T cell development and function. Further, the chemotactic capacity of MSCs, their interaction with the tumor microenvironment, and the intervention of immune-stimulatory molecules suggest possible exploitation of tumor necrosis factor-α (TNF-α) and CD40 ligand (CD40L) to genetically modify MSCs for enhanced cancer therapy. Both DCs and MSCs were isolated from BALB/c mice. DCs were then cocultured with MSCs transduced with TNF-α and/or CD40L [(TNF-α/CD40L)-MSCs]. Major DCs' maturation markers, DC and T cell cytokines such as interleukin-4, -6, -10, -12, TNF-α, tumor growth factor-β, as well as T cell proliferation, were assessed. Meantime, a BALB/c mouse breast tumor model was inducted by injecting 4T1 cells subcutaneously. Mice (n = 10) in each well-defined test groups (n = 13) were cotreated with DCs and/or (TNF-α/CD40L)-MSCs. The controls included untreated, empty vector-MSC, DC-lipopolysaccharide, and immature DC mouse groups. Eventually, cytokine levels from murine splenocytes, as well as tumor volume and survival of mice, were assessed. Compared with the corresponding controls, both in vitro and in vivo analyses showed induction of T helper 1 (Th1) as well as suppression of Th2 and Treg responses in test groups, which led to a valuable antitumor immune response. Further, the longest mouse survival was observed in mouse groups that were administered with DCs plus (TNF-α/CD40L)-MSCs. In our experimental setting, the present pioneered study demonstrates that concomitant genetic modification of MSCs with TNF-α and CD40L optimized the antitumor immunity response in the presence of DCs, meantime increasing the mouse lifespan.

Intravital biobank and personalized cancer therapy: the correlation with omics

Biobanks have played a decisive role in all aspects of the field of cancer, including pathogenesis, diagnosis, prognosis and treatment. The significance of cancer biobanks is epitomized through the appropriate application of various "-omic" techniques (omics). The mutually motivated relationship between biobanks and omics has intensified the development of cancer research. Human cancer tissues that are maintained in intravital biobanks (or living tissue banks) retain native tumor microenvironment, tissue architecture, hormone responsiveness and cell-to-cell signalling properties. Intravital biobanks replicate the structural complexity and heterogeneity of human cancers, making them an ideal platform for preclinical studies. The application of omics with intravital biobanks renders them more active, which makes it possible for the cancer-related evaluations to be dynamically monitored on a real-time basis. Integrating intravital biobank and modern omics will provide a useful tool for the discovery and development of new drugs or novel therapeutic strategies. More importantly, intravital biobanks may play an essential role in the creation of meaningful patient-tailored therapies as for personalized medicine.

DCA increases the antitumor effects of capecitabine in a mouse B16 melanoma allograft and a human non-small cell lung cancer A549 xenograft

PURPOSE

Capecitabine is one of the few chemotherapy drugs with high oral availability. Recently, sodium dichloroacetate (DCA) has shown great potential as an anticancer agent. In the present study, we assessed the anticancer effect of DCA in combination with capecitabine for cancers that modestly expressed TP.

METHODS

A mouse B16 melanoma allograft and a human non-small cell lung cancer A549 xenograft were used to assess the effect of DCA and capecitabine combined treatment. Histology and immunohistochemistry were used to detect the apoptosis and proliferation of cancer cells. Real-time PCR and Western blot were carried out to detect the expression of TP and caspases, respectively.

RESULTS

For the first time, we report that DCA increased the antitumor effects of capecitabine in a mouse B16 allograft and a human A549 xenograft by promoting apoptosis of tumor cells. DCA has little effect on the expression of TP.

CONCLUSIONS

Our finding suggests that DCA in combination with capecitabine might be potential as a new therapeutic regimen against some cancers.

Isolation, characterization and differentiation of cells expressing pluripotent/multipotent markers from adult human ovaries

Pluripotent stem cells are still generally accepted not to exist in adult human ovaries, although increasing studies confirm the presence of pluripotent/multipotent stem cells in adult mammalian ovaries, including those of humans. The aim of this study is to isolate, characterize and differentiate in vitro stem cells that originate from the adult human ovarian cortex and that express markers of pluripotency/multipotency. After enzymatic degradation of small ovarian cortex biopsies retrieved from 18 women, ovarian cell cultures were successfully established from 17 and the formation of cell colonies was observed. The presence of cells/colonies expressing some markers of pluripotency (alkaline phosphatase, surface antigen SSEA-4, OCT4, SOX-2, NANOG, LIN28, STELLA), germinal lineage (DDX4/VASA) and multipotency (M-CAM/CD146, Thy-1/CD90, STRO-1) was confirmed by various methods. Stem cells from the cultures, including small round SSEA-4-positive cells with diameters of up to 4 μm, showed a relatively high degree of plasticity. We were able to differentiate them in vitro into various types of somatic cells of all three germ layers. However, these cells did not form teratoma when injected into immunodeficient mice. Our results thus show that ovarian tissue is a potential source of stem cells with a pluripotent/multipotent character for safe application in regenerative medicine.

Trojan horse at cellular level for tumor gene therapies

Among innovative strategies developed for cancer treatments, gene therapies stand of great interest despite their well-known limitations in targeting, delivery, toxicity or stability. The success of any given gene-therapy is highly dependent on the carrier efficiency. New approaches are often revisiting the mythic trojan horse concept to carry therapeutic nucleic acid, i.e. DNAs, RNAs or small interfering RNAs, to pathologic tumor site. Recent investigations are focusing on engineering carrying modalities to overtake the above limitations bringing new promise to cancer patients. This review describes recent advances and perspectives for gene therapies devoted to tumor treatment, taking advantage of available knowledge in biotechnology and medicine.

The uncertain role of unmodified mesenchymal stem cells in tumor progression: what master switch?

Mesenchymal stem cells (MSCs) are emerging as promising gene vectors for cancer therapy because of their unique characteristics, including the ease of their expansion and genetic modification and their remarkable tumor-tropic properties. However, there remains a concern that MSCs may promote cancer progression. Surprisingly, there are conflicting reports within the literature describing both the promotion and inhibition of cancer progression by MSCs. The reasons for this discrepancy are still unknown. The surface markers, differentiation ability, and tumorigenic roles of MSCs, as well as their effect on immunoregulation, produce heterogeneity. In this review, we describe the heterogeneity of MSCs by the species from which they are derived, the methodology for their isolation and the context of their interactions with cancer cells. The conflicting roles of MSCs in tumor progression may be attributable to the bimodal effect of unmodified MSCs on immunoregulation. MSCs have been reported to suppress T-cell function and inhibit graft-versus-host disease (GVHD). On the other hand, MSCs elicit the graft-versus-tumor (GVT) effect in some cases. Selective allodepletion may be used to dissociate GVHD from the GVT effect. Understanding the conditions that balance GVHD and the GVT effect of MSCs may be crucial to advance cancer therapy research with respect to MSCs.

[Study on transduction of IL-24 gene in human bone marrow mesenchymal stem cells by lentiviral vector]

BACKGROUND

Up to know, no any study on using human bone marrow mesenchymal stem cells (hBMSCs) as cells carrier of tumor suppressor gene (IL-24) was reported. The aim of this study is to study the efficiency of transduction of hBMSCs by constructing the lentiviral vector in co-expressing enhanced green fluorescent protein (EGFP) gene and human IL-24 gene, and to lay a foundation for gene therapy of tumor in the future.

METHODS

The lentivector which contain IL-24 and EGFP constructed by recombinant DNA technology were co-transfected to 293FT cells with ViraPowerTM Lentiviral Packaging Mix. The recombinant lentivirus infected with hBMSCs were selected and purified by puromycin. Expression of IL-24 mRNA and IL-24 protein levels were detected by real-time quantitative PCR (qPCR) and ELISA.

RESULTS

The recombinant lentiviral vector of co-expressing IL-24 gene and EGFP gene were successfully constructed by multisite Gateway technology, virus can be packaged, purified and concentrated successfully, and the virus titer was 7.25×10⁷ PFU/mL. The efficiency of recombinant lentivirus to transduce hBMSCs can reach 100% after selection. The result of qPCR showed that the level of IL-24 mRNA expression in transduced group was significantly higher than that in non-transduced group (P<0.05); ELISA detection confirmed that IL-24 protein expression of transduced group was positive in supernatant and the concentration of IL-24 protein is 40 μg/L, while the non-transduced group was negative.

CONCLUSIONS

Lentiviral vector carrying recombinant IL-24 gene can effectively transduce hBMSCs and express IL-24 protein.

TRAIL-engineered pancreas-derived mesenchymal stem cells: characterization and cytotoxic effects on pancreatic cancer cells

Mesenchymal stem cells (MSCs) have attracted great interest in cancer therapy owing to their tumor-oriented homing capacity and the feasibility of autologous transplantation. Currently, pancreatic cancer patients face a very poor prognosis, primarily due to the lack of therapeutic strategies with an effective degree of specificity. Anticancer gene-engineered MSCs specifically target tumor sites and can produce anticancer agents locally and constantly. This study was performed to characterize pancreas-derived MSCs and investigate the effects of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-engineered MSCs on pancreatic cancer cells under different culture conditions. Pancreas-derived MSCs exhibited positive expression on CD44, CD73, CD95, CD105, negative on CD34 and differentiated into adipogenic and osteogenic cells. TRAIL expression was assessed by both enzyme-linked immunosorbent assay and western blot analysis. Different patterns of TRAIL receptor expression were observed on the pancreatic cancer cell lines, including PANC1, HP62, ASPC1, TRM6 and BXPC3. Cell viability was assessed using a real-time monitoring system. Pancreatic cancer cell death was proportionally related to conditioned media from MSC(nsTRAIL) and MSC(stTRAIL). The results suggest that MSCs exhibit intrinsic inhibition of pancreatic cancer cells and that this effect can be potentiated by TRAIL-transfection on death receptor-bearing cell types.

Supporting regenerative medicine by integrative dimensionality reduction

OBJECTIVE

The assessment of the developmental potential of stem cells is a crucial step towards their clinical application in regenerative medicine. It has been demonstrated that genome-wide expression profiles can predict the cellular differentiation stage by means of dimensionality reduction methods. Here we show that these techniques can be further strengthened to support decision making with i) a novel strategy for gene selection; ii) methods for combining the evidence from multiple data sets.

METHODS

We propose to exploit dimensionality reduction methods for the selection of genes specifically activated in different stages of differentiation. To obtain an integrated predictive model, the expression values of the selected genes from multiple data sets are combined. We investigated distinct approaches that either aggregate data sets or use learning ensembles.

RESULTS

We analyzed the performance of the proposed methods on six publicly available data sets. The selection procedure identified a reduced subset of genes whose expression values gave rise to an accurate stage prediction. The assessment of predictive accuracy demonstrated a high quality of predictions for most of the data integration methods presented.

CONCLUSION

The experimental results highlighted the main potentials of proposed approaches. These include the ability to predict the true staging by combining multiple training data sets when this could not be inferred from a single data source, and to focus the analysis on a reduced list of genes of similar predictive performance.