Regulated Mesenchymal Stem Cells Mediated Colon Cancer Therapy Assessed by Reporter Gene Based Optical Imaging. Int J Mol Sci. 2018;19. [PMID: 29584688 PMCID: PMC5979455 DOI: 10.3390/ijms19041002]

The effects of mesenchymal stem cells on the chemotherapy of colorectal cancer

Colorectal cancer (CRC) has been the third commonest cancer in the world. The prognosis of patients with CRC is related to the molecular subtypes and gene mutations, which is prone to recurrence, metastasis, and drug resistance. Mesenchymal stem cells (MSCs) are a group of progenitor ones with the capabilities of self-renewal， multi-directional differentiation, and tissue re-population, which could be isolated from various kinds of tissues and be differentiated into diverse cell types. In recent years, MSCs are applied for mechanisms study of tissue repairing, graft-versus-host disease (GVHD) and autoimmune-related disease, and tumor development, with the advantages of anti-inflammation, multi-lineage differentiation, and homing capability. Integrating the chemotherapy and MSCs therapy might provide a novel treatment approach for CRC patients. In this review, we summarize the current progress in the integrated treatment of integrating the MSCs and chemotherapy for CRC.

Engineered microtissues for the bystander therapy against cancer

Thymidine kinase expressing human adipose mesenchymal stem cells (TK-hAMSCs) in combination with ganciclovir (GCV) are an effective platform for antitumor bystander therapy in mice models. However, this strategy requires multiple TK-hAMSCs administrations and a substantial number of cells. Therefore, for clinical translation, it is necessary to find a biocompatible scaffold providing TK-hAMSCs retention in the implantation site against their rapid wash-out. We have developed a microtissue (MT) composed by TKhAMSCs and a scaffold made of polylactic acid microparticles and cell-derived extracellular matrix deposited by hAMSCs. The efficacy of these MTs as vehicles for TK-hAMSCs/GCV bystander therapy was evaluated in a rodent model of human prostate cancer. Subcutaneously implanted MTs were integrated in the surrounding tissue, allowing neovascularization and maintenance of TK-hAMSCs viability. Furthermore, MTs implanted beside tumors allowed TK-hAMSCs migration towards tumor cells and, after GCV administration, inhibited tumor growth. These results indicate that TK-hAMSCs-MTs are promising cell reservoirs for clinical use of therapeutic MSCs in bystander therapies.

Noninvasive in vivo cell tracking using molecular imaging: A useful tool for developing mesenchymal stem cell-based cancer treatment

Mounting evidence has emphasized the potential of cell therapies in treating various diseases by restoring damaged tissues or replacing defective cells in the body. Cell therapies have become a strong therapeutic modality by applying noninvasive in vivo molecular imaging for examining complex cellular processes, understanding pathophysiological mechanisms of diseases, and evaluating the kinetics/dynamics of cell therapies. In particular, mesenchymal stem cells (MSCs) have shown promise in recent years as drug carriers for cancer treatment. They can also be labeled with different probes and tracked in vivo to assess the in vivo effect of administered cells, and to optimize therapy. The exact role of MSCs in oncologic diseases is not clear as MSCs have been shown to be involved in tumor progression and inhibition, and the exact interactions between MSCs and specific cancer microenvironments are not clear. In this review, a multitude of labeling approaches, imaging modalities, and the merits/demerits of each strategy are outlined. In addition, specific examples of the use of MSCs and in vivo imaging in cancer therapy are provided. Finally, present limitations and future outlooks in terms of the translation of different imaging approaches in clinics are discussed.

Overexpression of protein regulator of cytokinesis 1 facilitates tumor growth and indicates unfavorable prognosis of patients with colon cancer

Background

Protein regulator of cytokinesis 1 (PRC1) has been reported to play important role in the pathogenesis of various cancers. However, its role in colon cancer has not been studied. Here, we aimed to investigate the biological functions and potential mechanism of PRC1 in colon cancer.

Methods

The expression level of PRC1 in colon cancer tissues and cell lines was detected by quantitative real-time polymerase chain reaction (qRT-PCR), Western blotting, and immunohistochemical (IHC) staining of a tissue microarray (TMA). Furthermore, colon cancer cell lines HCT116 and SW480 were treated with short hairpin RNAs against PRC1. The biological function of PRC1 was determined by MTT proliferation, colony formation assay, cell cycle, and apoptosis assays. Then, an in vivo tumor formation assay was conducted to explore the effects of PRC1 on tumor growth.

Results

The mRNA and protein expression levels of PRC1 were highly expressed in colon cancer tissues and cell lines. PRC1 expression was associated with clinicopathological characteristics and overall survival of patients with colon cancer. Knockdown of PRC1 could decrease proliferation and colony forming ability of colon cancer cells, as well as arrested more cells at G2/M phase and promoted cell apoptosis. In cancer cells, the expression pattern of protein regulators included in cell cycle and apoptosis progress were reverted by PRC1 down-regulation. Additionally, PRC1 down-regulation could suppress colon tumor growth and differentiation.

Conclusions

We confirmed that PRC1 was overexpressed in colon cancer and was associated with poor prognosis of colon cancer patients. PRC1 down-regulation could arrest cell cycle at G2/M stage, inhibit proliferation, and elicit apoptosis. These findings showed the potential of PRC1 to be used for therapeutic approaches in colon cancer.

Enhancing the Therapeutic Potential of Mesenchymal Stem Cells with the CRISPR-Cas System

Mesenchymal stem cells (MSCs), also known as multipotent mesenchymal stromal stem cells, are found in the perivascular space of several tissues. These cells have been subject of intense research in the last decade due to their low teratogenicity, as well as their ability to differentiate into mature cells and to secrete immunomodulatory and trophic factors. However, they usually promote only a modest benefit when transplanted in experimental disease models, one of the limitations for their clinical application. The CRISPR-Cas system, in turn, is highlighted as a simple and effective tool for genetic engineering. This system was tested in clinical trials over a relatively short period of time after establishing its applicability to the edition of the mammalian cell genome. Similar to the research evolution in MSCs, the CRISPR-Cas system demonstrated inconsistencies that limited its clinical application. In this review, we outline the evolution of MSC research and its applicability, and the progress of the CRISPR-Cas system from its discovery to the most recent clinical trials. We also propose perspectives on how the CRISPR-Cas system may improve the therapeutic potential of MSCs, making it more beneficial and long lasting.

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.

The Dynamic Roles of Mesenchymal Stem Cells in Colon Cancer

Colon cancer is still one of the most common causes of cancer in human and is characterized by lymphocyte infiltrates and originates from the epithelial cells found in the lining of colon or rectum of the gastrointestinal tract. Mesenchymal stem cells (MSCs) are composed of the multipotent stem cell group of stroma and can be differentiated as various cell lineages, such as fibroblasts, osteoblasts, and adipocytes. MSCs provide mechanical and structural support and have potential functions during tumor growth and metastasis. The efficacy of MSC-based therapies is partly dependent on the migration and homing of MSCs to tumors and metastatic sites. However, their migratory and engraftment potential is poorly understood. In this review, the characteristics and mechanisms of MSC's dynamic interaction with colon cancer were summarized, particularly the potential functions of MSCs on colon cancer, including its role in improving tumor growth and as a potential candidate for tumor therapy. Understanding MSC homing provides new insights into the manipulation of MSC and the improvement of their efficacy for colon cancer therapy.

Knockdown of anti-silencing function 1B histone chaperone induces cell apoptosis via repressing PI3K/Akt pathway in prostate cancer

Prostate cancer (PCa) is one of the most common malignancies among males worldwide. Anti-silencing function 1B histone chaperone (ASF1B) has been reported to be involved in PCa. The present study aimed to investigate the role and molecular mechanism of ASF1B in PCa. Data of genes were obtained from The Cancer Genome Atlas data- base. The core gene was identified using the DAVID website. Cell viability and colony formation were detected using a cell counting kit-8 assay and crystal violet staining, respectively. Cell cycle distribution and apoptosis were assessed using flow cytometry analysis. The corresponding factors were analyzed by reverse transcription-quantitative polymerase chain reaction and western blotting. It was demonstrated that ASF1B was highly expressed in the PCa tissues and cells compared with the non-PCa tissues and cells, respectively. While siRNA-ASF1B significantly reduced the viability and colony formation, it promoted apoptosis, G1 phase cell cycle arrest of LNCap as well as C4-2 cells. siRNA-ASF1B was revealed to significantly reduce the level of B-cell lymphoma-2 and cyclin D1, and enhance the expression levels of p53, caspase-3 and Bcl-2 associated X protein. Furthermore, the phosphorylation levels of phosphatidylinositol 3 kinase (PI3K) and protein kinase B (Akt) were significantly decreased in the siRNA-ASF1B group compared with the mock group. In summary, the present study demonstrated that silencing of ASF1B suppressed the proliferation, and promoted apoptosis and cell cycle arrest of PCa cells. Inhibition of the PI3K/Akt signaling pathway was pertinent to the role of si-ASF1B. This phenomenon suggests that the downregulation of ASF1B may aid in inhibiting the progression of PCa.

In vivo Non-invasive Imaging of Radio-Labeled Exosome-Mimetics Derived From Red Blood Cells in Mice

Exosomes are natural nano-sized membrane vesicles that have garnered recent interest owing to their potential as drug delivery vehicles. Though exosomes are effective drug carriers, their production and in vivo biodistribution are still not completely elucidated. We analyzed the production of exosome mimetics (EMs) from red blood cells (RBCs) and the radio-labeling of the RBC-EMs for in vivo imaging. Engineered EMs from RBCs were produced in large-scale by a one-step extrusion method, and further purified by density-gradient centrifugation. RBC-EMs were labeled with technetium-99m (^99mTc). For non-invasive imaging, ^99mTc (free) or ^99mTc-RBC-EMs were injected in mice, and their biodistribution was analyzed by gamma camera imaging. Animals were sacrificed, and organs were collected for further biodistribution analysis. RBC-EMs have similar characteristics as the RBC exosomes but have a 130-fold higher production yield in terms of particle numbers. Radiochemical purity of ^99mTc-RBC-EMs was almost 100% till 2 h reduced to 97% at 3 h. Radio-labeling did not affect the size and morphology of RBC-EMs. In contrast to free ^99mTc, in vivo imaging of ^99mTc-RBC-EMs in mice showed higher uptake in the liver and spleen, and no uptake in the thyroid. Ex vivo imaging confirmed the in vivo findings. Furthermore, fluorescent imaging confirmed the nuclear imaging findings. Immunofluorescent imaging revealed that the hepatic uptake of RBC-EMs was significantly mediated by kupffer cells (resident hepatic macrophages). Our results demonstrate a simple yet large-scale production method for a novel type of RBC-EMs, which can be effectively labeled with ^99mTc, and feasibly monitored in vivo by nuclear imaging. The RBC-EMs may be used as in vivo drug delivery vehicles.