Gene therapy of gastric cancer using LIGHT-secreting human umbilical cord blood-derived mesenchymal stem cells

Mesenchymal stem cells and their potential therapeutic benefits and challenges in the treatment and pathogenesis of gastric cancer

Mesenchymal stem/stromal cells (MSCs) are acknowledged for their remarkable ability to undergo differentiation into various cell types. In addition, they exhibit anti-tumor characteristics, prompting endeavors to modify MSCs for employment in cancer therapies. On the contrary, it is imperative to recognize that MSCs have been extensively linked to pathways that facilitate the advancement of tumors. Numerous research studies have sought to modify MSCs for clinical application; however, the outcomes have been ambiguous, potentially due to the heterogeneity of MSC populations. Furthermore, the conflicting roles of MSCs in suppressing and promoting tumor growth present a challenge to the appropriateness of their use in anti-cancer therapies. Currently, there exists a lack of comprehensive comprehension concerning the anti-tumor and pro-tumor characteristics of MSCs for gastric cancer (GC). This article discusses the influence of MSCs on GC, the underlying mechanisms, the origins of MSCs, and their effects. This review article also elucidates how MSCs exhibit dual characteristics of promoting and inhibiting tumor growth. Hence, it is of utmost importance that clinical inquiries aimed at utilizing MSCs as a therapeutic intervention for cancer consider the potentiality of MSCs to accelerate the progression of GC. It is crucial to exercise caution throughout the process of developing MSC-based cellular therapies to enhance their anti-cancer attributes while simultaneously eliminating their tumor-promoting impacts.

Gastric cancer and mesenchymal stem cell-derived exosomes: from pro-tumorigenic effects to anti-cancer vehicles

Gastric cancer (GC) is one of the most prevalent malignancies in the world, with a high mortality rate in both women and men. Conventional treatments, like chemotherapy, radiotherapy and surgery, are facing some drawbacks like acquired drug resistance and various side effects, leading to cancer recurrence and increased morbidity; thus, development of novel approaches in targeted therapy would be very beneficial. Exosomes, extracellular vesicles with a size distribution of sub-150 nm, interplay in physiological and pathophysiological cell-cell communications and can pave the way for targeted cancer therapy. Accumulating pieces of evidence have indicated that exosomes derived from mesenchymal stem cells (MSC-EXs) can act as a double-edged sword in some cancers. The purpose of this review is to assess the differences between stem cell therapy and exosome therapy. Moreover, our aim is to demonstrate how naïve MSCs transform into GC-MSCs in the tumor microenvironment. Additionally, the tumorigenic and anti-proliferation effects of MSC-EXs derived from different origins were investigated. Finally, we suggest potential modifications and combination options that involve utilizing MSC-EXs from the foreskin and umbilical cord as promising sources to enhance the efficacy of gastric cancer treatment. This approach is presented in contrast to bone marrow cells, which are more heterogeneous, age-related, and are also easily affected by the patient's circulation system.

Human umbilical cord blood mesenchymal stem cells-derived exosomal microRNA-503-3p inhibits progression of human endometrial cancer cells through downregulating MEST

Endometrial cancer (EC) is a group of epithelial malignant tumors that occur in the endometrium. The specific pathogenesis is not revealed, hence, the goal of this study was to investigate the influence of human umbilical cord blood mesenchymal stem cells (hUMSCs)-derived exosomal microRNA-503-3p (miR-503-3p) on human EC cells by mediating mesoderm-specific transcript (MEST). The binding relationship between MiR-503-3p and MEST was searched. HUMSCs were collected and exosomes (Exos) were isolated and identified. Human EC cell lines HEC-1B and RL95-2 were transfected with elevated miR-503-3p or silenced MEST vector or co-cultured with Exos to figure their roles in biological functions of EC cells. The in vitro effect of miR-503-3p, MEST, and Exos on EC cells was further verified in vivo. MEST was a target of miR-503-3p. Overexpression of miR-503-3p or reduction of MEST suppressed the biological functions of EC cells. Enhanced MEST expression mitigated the role of upregulated miR-503-3p on the growth of EC cells. HUMSCs-derived Exos suppressed EC cell growth, upregulated miR-503-3p-modified HUMSCs-derived Exos had a more obvious inhibitory effect on EC cell growth. The anti-tumor effect of elevated miR-503-3p, silenced MEST, and HUMSCs-derived Exos were verified in nude mice. This study highlights that hUMSCs-derived exosomal miR-503-3p inhibits EC development by suppressing MEST, which is of great benefit to EC therapy.

Hepatic stellate cell mediates transcription of TNFSF14 in hepatocellular carcinoma cells via H2S/CSE-JNK/JunB signaling pathway

Hepatic stellate cells (HSC) and hydrogen sulfide (H2S) both play important roles in the development of hepatocellar carcinoma (HCC). Whereas, in the microenvironment of HCC, whether HSC participate in regulating the biological process of HCC cells by releasing H2S remains elusive. In vitro, Flow cytometry (FCM), CCK-8, RNA-sequencing, Western blotting, RT-qPCR, immunofluorescence and ChIP assays were carried out in the HCC cells to investigate the effect of H2S on biological functions and JNK/JunB-TNFSF14 signaling pathway. Specimens from HCC patients were analyzed by RT-qPCR and Western blotting assays for evaluating the expression of TNFSF14 and CSE. Statistical analysis was used to analyze the correlation between TNFSF14 expression and clinical data of HCC patients. Based on the FCM and CCK-8 results, we found the LX-2 cells were able to induce HCC cells apoptosis through releasing H2S. RNA-sequencing, RT-qPCR, and Western blotting results showed that TNFSF14 gene was upregulated in both LX-2 and NaHS group. NaHS treated in HCC cells led to JNK/JunB signaling pathway activating and greater binding of p-JunB to its responsive elements on TNFSF14 promoter. Impairment of TNFSF14 induction alleviated LX-2 and NaHS induced apoptosis of HepG2 and PLC/PRF/5 cells. Furthermore, TNFSF14 expression in HCC tissues was lower than the adjacent tissue. HCC patients with low expression of TNFSF14 had higher malignant degree and poor prognosis. In summary, demonstration of the involvement of HSC-derived H2S in JNK/JunB mediated expression of TNFSF14 gene strongly indicates H2S palys an important role in the regulation of HCC apoptosis.

The Roles of Mesenchymal Stem Cells in Gastrointestinal Cancers

Mesenchymal stem cells (MSCs) were reported to have strong immunomodulatory ability, and inhibit the proliferation of T cells and their immune response through cell-to-cell interactions and the generation of cytokines. With high differentiation potential and self-renewal ability, MSCs are considered to function in alleviating inflammatory responses, promoting tissue regeneration and inhibiting tissue fibrosis formation. As the most common malignancies, gastrointestinal (GI) cancers have high incidence and mortality. The accurate diagnosis, exact prognosis and treatment of GI cancers have always been a hot topic. Therefore, the potential applications of MSCs in terms of GI cancers are receiving more and more attention. Recently, there is increasing evidence that MSCs may serve as a key point in the growth, metastasis, inhibition, treatment and prognosis of GI cancers. In this review, we summarized the roles of MSCs in GI cancers, mainly focusing on esophageal cancer (EC), gastric cancer (GC), liver cancer (LC), colorectal cancer (CRC) and pancreatic cancer. Besides, we proposed MSCs as potential targets and treatment strategies for the effective treatment of GI cancers, which may provide better guidance for the clinical treatment of GI cancers.

Exosomal miR-150 partially attenuated acute lung injury by mediating microvascular endothelial cells and MAPK pathway

BACKGROUND

Acute lung injury (ALI) is a respiratory disease with high morbidity and mortality rates. Currently, there is no effective treatment to complement mechanical ventilation. Exosomes and microRNAs (miRNAs) are promising agents for the management of this disease.

METHODS

Exosomes were isolated from mouse bone marrow stromal stem cells (BMSCs). The levels of two miRNAs, miR-542-3P and miR-150, in exosomes were determined using RT-PCR, and miR-150 was selected for further study. ALI model was established in mice using lipopolysaccharides, and then, they were treated with saline, exosomes, miRNA agomirs, or miRNA antagomirs. The concentrations of TNF-α, IL-6, and IL-1β and the number of neutrophils and macrophages in the bronchoalveolar lavage fluid were measured. The wet/dry weight ratio of the lung tissue was calculated, and tissue pathology and apoptosis were observed using hematoxylin and eosin and terminal deoxynucleotidyl transferase dUTP nick-end labeling staining. CD34 and VE-cadherin expression was detected using immunofluorescence. Proteins associated with apoptosis and MAPK signaling were detected using Western blotting, and miR-150 expression in lung tissue was evaluated using RT-PCR.

RESULTS

We successfully isolated BMSCs and exosomes and showed that the level of miR-150 was significantly higher than that of miR-542-3p. Exosomes and miR-150 reduced inflammation and lung edema while maintaining the integrity of the alveolar structure. They also mitigated microvascular endothelial cell injury by regulating the caspase-3, Bax/Bcl-2, and MAPK signaling.

CONCLUSIONS

Exosomal miR-150 attenuates lipopolysaccharide-induced ALI through the MAPK pathway.

Mesenchymal Stem Cells in Gastric Cancer: Vicious but Hopeful

Tumor progression depends on the collaborative interactions between tumor cells and the surrounding stroma. First-line therapies direct against cancer cells may not reach a satisfactory outcome, such as gastric cancer (GC), with high risk of recurrence and metastasis. Therefore, novel treatments and drugs target the effects of stroma components are to be promising alternatives. Mesenchymal stem cells (MSC) represent the decisive components of tumor stroma that are found to strongly affect GC development and progression. MSC from bone marrow or adjacent normal tissues express homing profiles in timely response to GC-related inflammation signals and anchor into tumor bulks. Then the newly recruited “naïve” MSC would achieve phenotype and functional alternations and adopt the greater tumor-supporting potential under the reprogramming of GC cells. Conversely, both new-comers and tumor-resident MSC are able to modulate the tumor biology via aberrant activation of oncogenic signals, metabolic reprogramming and epithelial-to-mesenchymal transition. And they also engage in remodeling the stroma better suited for tumor progression through immunosuppression, pro-angiogenesis, as well as extracellular matrix reshaping. On the account of tumor tropism, MSC could be engineered to assist earlier diagnosis of GC and deliver tumor-killing agents precisely to the tumor microenvironment. Meanwhile, intercepting and abrogating vicious signals derived from MSC are of certain significance for the combat of GC. In this review, we mainly summarize current advances concerning the reciprocal metabolic interactions between MSC and GC and their underlying therapeutic implications in the future.

Mesenchymal stem/stromal cell-based therapy: mechanism, systemic safety and biodistribution for precision clinical applications

Mesenchymal stem/stromal cells (MSCs) are a promising resource for cell-based therapy because of their high immunomodulation ability, tropism towards inflamed and injured tissues, and their easy access and isolation. Currently, there are more than 1200 registered MSC clinical trials globally. However, a lack of standardized methods to characterize cell safety, efficacy, and biodistribution dramatically hinders the progress of MSC utility in clinical practice. In this review, we summarize the current state of MSC-based cell therapy, focusing on the systemic safety and biodistribution of MSCs. MSC-associated risks of tumor initiation and promotion and the underlying mechanisms of these risks are discussed. In addition, MSC biodistribution methodology and the pharmacokinetics and pharmacodynamics of cell therapies are addressed. Better understanding of the systemic safety and biodistribution of MSCs will facilitate future clinical applications of precision medicine using stem cells.

Prospects for the therapeutic development of umbilical cord blood-derived mesenchymal stem cells

Umbilical cord blood (UCB) is a primitive and abundant source of mesenchymal stem cells (MSCs). UCB-derived MSCs have a broad and efficient therapeutic capacity to treat various diseases and disorders. Despite the high latent self-renewal and differentiation capacity of these cells, the safety, efficacy, and yield of MSCs expanded for ex vivo clinical applications remains a concern. However, immunomodulatory effects have emerged in various disease models, exhibiting specific mechanisms of action, such as cell migration and homing, angiogenesis, anti-apoptosis, proliferation, anti-cancer, anti-fibrosis, anti-inflammation and tissue regeneration. Herein, we review the current literature pertaining to the UCB-derived MSC application as potential treatment strategies, and discuss the concerns regarding the safety and mass production issues in future applications.

The impact of TNFSF14 on prognosis and immune microenvironment in clear cell renal cell carcinoma

BACKGROUND

TNFSF14 has been proven to play an important role in various types of tumors. However, its function in renal cell carcinoma (RCC) has not yet been fully elucidated.

OBJECTIVE

In order to explore molecular mechanism of RCC, we evaluated the effect of TNFSF14 on RCC progression, prognosis and immune microenvironment.

METHODS

Using TCGA database, the differential expression of TNFSF14 and its relationships between clinicopathological features and prognosis were determined. Cox univariate and multivariate analyses were successively performed to identify whether TNFSF14 was an independent prognostic factor. The discriminating ability of TNFSF14 in RCC prognosis analysis was validated under the same clinical subgroups. Tumor mutational burden (TMB) of each RCC samples was calculated and the differential expression of TNFSF14 between high- and low-TMB groups was analyzed. The immune abundances of 22 leukocyte subtypes in each RCC samples were presented through the CIBERSORT algorithm. TIMER database was used to explore the relationships between copy number of TNFSF14 and the infiltration levels of 6 immune cells.

RESULTS

Overexpression of TNFSF14 implied adverse clinicopathological features and poor prognosis. Meanwhile, TNFSF14 was identified as an independent prognostic factor (HR = 1.047, P = 0.028) and possessed prevalent applicability in RCC prognostic analysis. TNFSF14 was upregulated in high-TMB group than that in low-TMB group (Log₂FC = 0.722). Moreover, overexpression of TNFSF14 brought alteration of immune abundance of 8 leukocyte subtypes. Besides, somatic copy number alteration (SCNA) of TNFSF14 was associated with infiltration levels of 6 immune cells.

CONCLUSIONS

TNFSF14 has crucial impact on progression, prognosis and immune microenvironment in RCC. Besides, TNFSF14 may be a potential biomarker for predicting the efficacy and response rate of RCC immunotherapy.

Evaluation of the expression of bone marrow-derived mesenchymal stem cells and cancer-associated fibroblasts in the stroma of gastric cancer tissue

AIM

Cancer-associated fibroblasts (CAFs) generated by bone marrow-derived mesenchymal stem cells (BM-MSCs) play an important role in cancer progression. In this study, we investigated the relationships of BM-MSCs and CAFs in resected gastric cancers with the clinicopathological factors of patients.

METHODS

We analyzed 120 gastric cancer patients who underwent gastrectomy. Immunostaining was performed with an anti-CD271 antibody (BM-MSCs) and anti-α-smooth muscle actin (αSMA) antibody (CAFs). Staining intensity was used to divide patients into low and high expression groups. Observation sites in cancer tissues were invasive, central, and whole portions.

RESULTS

Expression of αSMA was significantly related to depth of tumor invasion (T), lymph node metastasis (N), lymphatic invasion (ly), venous invasion (v), and stage. Expression of CD271 was significantly related to v, stage, stromal volume, and tumor infiltration pattern (INF). Overall survival (OS) of the high expression group was significantly lower than that of the low expression group for both αSMA and CD271. Multivariate analysis showed that N, αSMA (whole), and CD271 (invasive) were independent prognostic factors.

CONCLUSIONS

Cancer-associated fibroblasts and BM-MSCs are related to the progression, invasion, and prognosis of gastric cancer and may be therapeutic targets of gastric cancer.

Interplay between mesenchymal stem cell and tumor and potential application

Mesenchymal stem cells (MSCs) possess the capabilities of self-renewal and multipotent differentiation. Firstly isolated from bone marrow, MSCs are subsequently identified from various post-natal tissue types. Based the differentiation into tissue-specific cells, MSCs were capable of replacing damaged and diseased tissues. In addition, MSCs have been demonstrated to possess important immunomodulatory properties. Increasing data showed that MSCs exhibited tropism for sites of the tumor microenvironment and interacted with tumor cells closely through paracrine signaling. Therefore, better understanding of crosstalk between MSCs and tumor cells will be able to develop potential strategies in the treatment of tumors in the future. Herein, we summarize the research progress of the influence of MSCs on tumor cells and the prospect of their application in tumor therapy in this review.

Efficacy of mesenchymal stem cells in the treatment of gastrointestinal malignancies

Mesenchymal stem cells (MSCs), which are a kind of stem cell, possess an immune privileged nature, tumour homing features, and multi-lineage differentiation ability. MSCs have been studied in many fields, such as tissue engineering, nervous system diseases, and cancer treatment. In recent years, an increasing number of researchers have focused on the effects of MSCs on various kinds of tumours. However, the concrete anticancer efficacy of MSCs is still controversial. Gastrointestinal (GI) malignancies are the major causes of cancer-related death worldwide. The interactions of MSCs and GI cancer cells in specific conditions have attracted increasing attention. In this review, we introduce the characteristics of MSCs and analyse the effects of MSCs on GI malignancies, including gastric cancer, hepatoma, pancreatic cancer, and colorectal cancer. In addition, we also provide our perspectives on why MSCs may play different roles in GI malignancies and further research directions to increase the treatment efficacy of MSCs on GI malignancies.

Engineering Hematopoietic Cells for Cancer Immunotherapy: Strategies to Address Safety and Toxicity Concerns

Advances in cancer immunotherapies utilizing engineered hematopoietic cells have recently generated significant clinical successes. Of great promise are immunotherapies based on chimeric antigen receptor-engineered T (CAR-T) cells that are targeted toward malignant cells expressing defined tumor-associated antigens. CAR-T cells harness the effector function of the adaptive arm of the immune system and redirect it against cancer cells, overcoming the major challenges of immunotherapy, such as breaking tolerance to self-antigens and beating cancer immune system-evasion mechanisms. In early clinical trials, CAR-T cell-based therapies achieved complete and durable responses in a significant proportion of patients. Despite clinical successes and given the side effect profiles of immunotherapies based on engineered cells, potential concerns with the safety and toxicity of various therapeutic modalities remain. We discuss the concerns associated with the safety and stability of the gene delivery vehicles for cell engineering and with toxicities due to off-target and on-target, off-tumor effector functions of the engineered cells. We then overview the various strategies aimed at improving the safety of and resolving toxicities associated with cell-based immunotherapies. Integrating failsafe switches based on different suicide gene therapy systems into engineered cells engenders promising strategies toward ensuring the safety of cancer immunotherapies in the clinic.

pIL6-TRAIL-engineered umbilical cord mesenchymal/stromal stem cells are highly cytotoxic for myeloma cells both in vitro and in vivo

Background

Mesenchymal/stromal stem cells (MSCs) are favorably regarded in anti-cancer cytotherapies for their spontaneous chemotaxis toward inflammatory and tumor environments associated with an intrinsic cytotoxicity against tumor cells. Placenta-derived or TRAIL-engineered adipose MSCs have been shown to exert anti-tumor activity in both in-vitro and in-vivo models of multiple myeloma (MM) while TRAIL-transduced umbilical cord (UC)-MSCs appear efficient inducers of apoptosis in a few solid tumors. However, apoptosis is not selective for cancer cells since specific TRAIL receptors are also expressed by a number of normal cells. To overcome this drawback, we propose to transduce UC-MSCs with a bicistronic vector including the TRAIL sequence under the control of IL-6 promoter (pIL6) whose transcriptional activation is promoted by the MM milieu.

Methods

UC-MSCs were transduced with a bicistronic retroviral vector (pMIGR1) encoding for green fluorescent protein (GFP) and modified to include the pIL6 sequence upstream of the full-length human TRAIL cDNA. TRAIL expression after stimulation with U-266 cell conditioned medium, or IL-1α/IL-1β, was evaluated by flow cytometry, confocal microscopy, real-time PCR, western blot analysis, and ELISA. Apoptosis in MM cells was assayed by Annexin V staining and by caspase-8 activation. The cytotoxic effect of pIL6-TRAIL⁺-GFP⁺-UC-MSCs on MM growth was evaluated in SCID mice by bioluminescence and ex vivo by caspase-3 activation and X-ray imaging. Statistical analyses were performed by Student’s t test, ANOVA, and logrank test for survival curves.

Results

pIL6-TRAIL⁺-GFP⁺-UC-MSCs significantly expressed TRAIL after stimulation by either conditioned medium or by IL-1α/IL-1β, and induced apoptosis in U-266 cells. Moreover, when systemically injected in SCID mice intratibially xenografted with U-266, those cells underwent within MM tibia lesions and significantly reduced the tumor burden by specific induction of apoptosis in MM cells as revealed by caspase-3 activation.

Conclusions

Our tumor microenvironment-sensitive model of anti-MM cytotherapy is regulated by the axis pIL6/IL-1α/IL-1β and appears suitable for further preclinical investigation not only in myeloma bone disease in which UC-MSCs would even participate to bone healing as described, but also in other osteotropic tumors whose milieu is enriched of cytokines triggering the pIL6.

Engineered Mesenchymal Stem Cells as an Anti-Cancer Trojan Horse

Cell-based gene therapy holds a great promise for the treatment of human malignancy. Among different cells, mesenchymal stem cells (MSCs) are emerging as valuable anti-cancer agents that have the potential to be used to treat a number of different cancer types. They have inherent migratory properties, which allow them to serve as vehicles for delivering effective therapy to isolated tumors and metastases. MSCs have been engineered to express anti-proliferative, pro-apoptotic, and anti-angiogenic agents that specifically target different cancers. Another field of interest is to modify MSCs with the cytokines that activate pro-tumorigenic immunity or to use them as carriers for the traditional chemical compounds that possess the properties of anti-cancer drugs. Although there is still controversy about the exact function of MSCs in the tumor settings, the encouraging results from the preclinical studies of MSC-based gene therapy for a large number of tumors support the initiation of clinical trials.

Opposite Effects of Coinjection and Distant Injection of Mesenchymal Stem Cells on Breast Tumor Cell Growth

: Mesenchymal stem cells (MSCs) usually promote tumor growth and metastasis. By using a breast tumor 4T1 cell-based animal model, this study determined that coinjection and distant injection of allogeneic bone marrow-derived MSCs with tumor cells could exert different effects on tumor growth. Whereas the coinjection of MSCs with 4T1 cells promoted tumor growth, surprisingly, the injection of MSCs at a site distant from the 4T1 cell inoculation site suppressed tumor growth. We further observed that, in the distant injection model, MSCs decreased the accumulation of myeloid-derived suppressor cells and regulatory T cells in tumor tissues by enhancing proinflammatory factors such as interferon-γ, tumor necrosis factor-α, Toll-like receptor (TLR)-3, and TLR-4, promoting host antitumor immunity and inhibiting tumor growth. Unlike previous reports, this is the first study reporting that MSCs may exert opposite roles on tumor growth in the same animal model by modulating the host immune system, which may shed light on the potential application of MSCs as vehicles for tumor therapy and other clinical applications.

SIGNIFICANCE

Mesenchymal stem cells (MSCs) have been widely investigated for their potential roles in tissue engineering, autoimmune diseases, and tumor therapeutics. This study explored the impact of coinjection and distant injection of allogeneic bone marrow-derived MSCs on mouse 4T1 breast cancer cells. The results showed that the coinjection of MSCs and 4T1 cells promoted tumor growth. MSCs might act as the tumor stromal precursors and cause immunosuppression to protect tumor cells from immunosurveillance, which subsequently facilitated tumor metastasis. Interestingly, the distant injection of MSCs and 4T1 cells suppressed tumor growth. Together, the results of this study revealed the dual functions of MSCs in immunoregulation.

VEGF Enhances the Migration of MSCs in Neural Differentiation by Regulating Focal Adhesion Turnover

Mesenchymal stem cells (MSCs) hold great promise in neural regeneration, due to their intrinsic neuronal potential and migratory tropism to damaged nervous tissues. However, the chemotactic signals mediating the migration of MSCs remain poorly understood. Here, we investigated the regulatory roles for focal adhesion kinase (FAK) and Rac1 in vascular endothelial growth factor (VEGF)-stimulated migration of MSCs in neural differentiation. We found that MSCs in various differentiation states show significant different chemotactic responses to VEGF and cells in 24-h preinduction state possess the highest migration speed and efficiency. FAK, as the downstream signaling molecule, is involved in the VEGF-induced migration by regulating the assembly and distribution of focal adhesions (FAs) and reorganization of F-actin. The features of FAs and cytoskeletons and the ability of lamellipodia formation are closely related to the neural differentiation states of MSCs. VEGF promotes FA formation with an asymmetric distribution of FAs and induces the activation of Y397-FAK and Y31/118-paxillin of undifferentiated and 24-h preinduced MSCs in a time-dependent manner. Inhibition of FAK by PF-228 or expressing FAK-Y397F mutant impairs the dynamics of FAs in MSCs during VEGF-induced migration. Furthermore, Rac1 regulates FA formation in a FAK-dependent manner. Overexpression of constitutive activated mutants of Rac1 increases the number of FAs in undifferentiated and 24-h preinduced MSCs, while VEGF-induced increase of FA formation is decreased by inhibiting FAK by PF-228. Collectively, these results demonstrate that FAK and Rac1 signalings coordinately regulate the dynamics of FAs during VEGF-induced migration of MSCs in varying neural differentiation states.

Therapeutic Lymphoid Organogenesis in the Tumor Microenvironment

The inflammatory status of the tumor microenvironment (TME) has been heavily investigated in recent years. Chemokine- and cytokine-signaling pathways such as CCR7, CXCR5, lymphotoxin, and IL-36, which are involved in the generation of secondary lymphoid organs and effector immune responses, are now recognized as having value both as prognostic factors and as immunomodulatory therapeutics in the context of cancer. Furthermore, when produced in the TME, these mediators have been shown to promote the recruitment of immune cells, including T cells, B cells, dendritic cells (DCs), and other specialized immune cell subsets such as follicular DCs and T follicular helper cells, in association with the formation of "tertiary" lymphoid structures (TLSs) within or adjacent to sites of disease. Although TLSs are composed of a heterogeneous collection of immune cell types, whose composition differs based on cancer subtype, the qualitative presence of TLSs has been shown to represent a biomarker of good prognosis for cancer patients. A comprehensive understanding of the role each of these pathways plays within the TME may support the rational design of future immunotherapies to selectively promote/bolster TLS formation and function, leading to improved clinical outcomes across the vast range of solid cancer types.

Mesenchymal stem cells expressing interleukin-18 suppress breast cancer cells in vitro

Breast cancer is the most common malignancy among females throughout the world. Current treatments have unsatisfactory outcomes due to the dispersed nature of certain types of the disease. The development of a more effective therapy for breast cancer has long been one of the most elusive goals of cancer gene therapy. In the present study, human mesenchymal stem cells derived from umbilical cord (hUMSCs) genetically modified with interleukin 18 (IL-18) gene were used to study the effect of hUMSCs/IL-18 on the growth, migration and invasion of MCF-7 and HCC1937 cells in vitro. The hUMSCs could be efficiently modified by lentiviral systems and stably expressed IL-18 protein. hUMSCs/IL-18, but not hUMSCs without the IL-18 gene transduction, significantly suppressed the proliferation, migration and invasion of the MCF-7 and HCC1937 cells. The mechanism of this proliferation suppression may have involved the induction of G1- to S-phase arrest of the breast cancer cells by the hUMSCs/IL-18. In conclusion, hUMSCs/IL-18 can suppress the proliferation, migration and invasion of breast cancer cells in vitro and may provide an approach for a novel antitumor therapy in breast cancer.

Large-scale expansion of Wharton's jelly-derived mesenchymal stem cells on gelatin microbeads, with retention of self-renewal and multipotency characteristics and the capacity for enhancing skin wound healing

INTRODUCTION

Successful stem cell therapy relies on large-scale generation of stem cells and their maintenance in a proliferative multipotent state. This study aimed to establish a three-dimension culture system for large-scale generation of hWJ-MSC and investigated the self-renewal activity, genomic stability and multi-lineage differentiation potential of such hWJ-MSC in enhancing skin wound healing.

METHODS

hWJ-MSC were seeded on gelatin microbeads and cultured in spinning bottles (3D). Cell proliferation, karyotype analysis, surface marker expression, multipotent differentiation (adipogenic, chondrogenic, and osteogenic potentials), and expression of core transcription factors (OCT4, SOX2, NANOG, and C-MYC), as well as their efficacy in accelerating skin wound healing, were investigated and compared with those of hWJ-MSC derived from plate cultres (2D), using in vivo and in vitro experiments.

RESULTS

hWJ-MSC attached to and proliferated on gelatin microbeads in 3D cultures reaching a maximum of 1.1-1.30×10(7) cells on 0.5 g of microbeads by days 8-14; in contrast, hWJ-MSC derived from 2D cultures reached a maximum of 6.5 -11.5×10(5) cells per well in a 24-well plate by days 6-10. hWJ-MSC derived by 3D culture incorporated significantly more EdU (P<0.05) and had a significantly higher proliferation index (P<0.05) than those derived from 2D culture. Immunofluorescence staining, real-time PCR, flow cytometry analysis, and multipotency assays showed that hWJ-MSC derived from 3D culture retained MSC surface markers and multipotency potential similar to 2D culture-derived cells. 3D culture-derived hWJ-MSC also retained the expression of core transcription factors at levels comparable to their 2D culture counterparts. Direct injection of hWJ-MSC derived from 3D or 2D cultures into animals exhibited similar efficacy in enhancing skin wound healing.

CONCLUSIONS

Thus, hWJ-MSC can be expanded markedly in gelatin microbeads, while retaining MSC surface marker expression, multipotent differential potential, and expression of core transcription factors. These cells also efficiently enhanced skin wound healing in vivo, in a manner comparable to that of hWJ-MSC obtained from 2D culture.

Cells as delivery vehicles for cancer therapeutics

Cell-based therapeutics have advanced significantly over the past decade and are poised to become a major pillar of modern medicine. Three cell types in particular have been studied in detail for their ability to home to tumors and to deliver a variety of different payloads. Neural stem cells, mesenchymal stem cells and monocytes have each been shown to have great potential as future delivery systems for cancer therapy. A variety of other cell types have also been studied. These results demonstrate that the field of cell-based therapeutics will only continue to grow.

Combined gene therapy system pcDNA 3.1(-)-shVEGF/yCDglyTK inhibits proliferation of gastric cancer cells

AIM: To observe the effect of combined gene therapy system pcDNA 3.1(-)-shVEGF/yCDglyTK, which is mediated by calcium phosphate nanoparticles, on the proliferation of human gastric cancer cells.

METHODS: Expression plasmid vectors pcDNA3.1(-) NULL, pGenesil-1-hVEGF4-shRNA, pcDNA3.1(-)-CV-yCDglyTK, or pcDNA3.1(-)-shVEGF/yCDglyTK were transfected into human gastric cancer cell line SGC7901. The mRNA and protein expression of yCDglyTK and VEGF was detected by RT-PCR and Western blot, respectively. The proliferation of transfected cells was analyzed by MTT assay. Apoptosis of SGC7901 cells was analyzed by flow cytometry.

RESULTS: After transfection with plasmid pcDNA3.1(-)-shVEGF/yCDglyTK, yCDglyTK mRNA and protein was detectable, and expression of VEGF was decreased by 30.3%. Compared to cells transfected with plasmid pcDNA3.1(-)-CV-yCDglyTK, cells treated with the combined gene therapy system showed more significant proliferation inhibition (P < 0.05) and apoptosis (apoptosis rate: 67.9% ± 4.78%).

CONCLUSION: The combined gene therapy system pcDNA3.1(-)-shVEGF/yCDglyTK has stronger killing effect on gastric cancer cells than RNA interference or suicide gene alone.

Gastric cancer stem cells: a novel therapeutic target

Gastric cancer remains one of the leading causes of global cancer mortality. Multipotent gastric stem cells have been identified in both mouse and human stomachs, and they play an essential role in the self-renewal and homeostasis of gastric mucosa. There are several environmental and genetic factors known to promote gastric cancer. In recent years, numerous in vitro and in vivo studies suggest that gastric cancer may originate from normal stem cells or bone marrow-derived mesenchymal cells, and that gastric tumors contain cancer stem cells. Cancer stem cells are believed to share a common microenvironment with normal niche, which play an important role in gastric cancer and tumor growth. This mini-review presents a brief overview of the recent developments in gastric cancer stem cell research. The knowledge gained by studying cancer stem cells in gastric mucosa will support the development of novel therapeutic strategies for gastric cancer.

Immunotherapeutic organoids: a new approach to cancer treatment

Therapeutic monoclonal antibodies have revolutionized the treatment of cancer and other diseases. However, several limitations of antibody-based treatments, such as the cost of therapy and the achievement of sustained plasma levels, should be still addressed for their widespread use as therapeutics. The use of cell and gene transfer methods offers additional benefits by producing a continuous release of the antibody with syngenic glycosylation patterns, which makes the antibody potentially less immunogenic. In vivo secretion of therapeutic antibodies by viral vector delivery or ex vivo gene modified long-lived autologous or allogeneic human mesenchymal stem cells may advantageously replace repeated injection of clinical-grade antibodies. Gene-modified autologous mesenchymal stem cells can be delivered subcutaneously embedded in a non-immunogenic synthetic extracellular matrix-based scaffold that guarantees the survival of the cell inoculum. The scaffold would keep cells at the implantation site, with the therapeutic protein acting at distance (immunotherapeutic organoid), and could be retrieved once the therapeutic effect is fulfilled. In the present review we highlight the practical importance of living cell factories for in vivo secretion of recombinant antibodies.