Third trimester amniotic fluid (AF)-derived human mesenchymal stem cells (MSCs) can be greatly expanded in vitro and induced to differentiate into multiple mesenchymal cell types. This study aimed to investigate the biological characteristics of MSCs from third trimester AF as a new source of therapeutic stem cells. Forty third trimester AF samples were obtained from healthy women who underwent elective caesarean section for breech presentation. A simple culture protocol for MSCs was used. A cell growth curve was drawn, and cell surface antigens and cytokines were analysed by immunofluorescent staining, reverse transcription-polymerase chain reaction and flow cytometry. MSCs from third-trimester AF were successfully isolated, cultured and enriched. MSCs expanded extensively without feeders, they were not tumourigenic and were induced to differentiate into osteocytes. Surface antigens were analysed and found to express the pluripotency marker Oct-4. Considering the great feasibility of biomedical engineering using MSCs, third trimester AF may provide a rich source for investigation of human MSCs.

Alkylating agents such as temozolomide (TMZ) are effective anticancer drugs for treating a variety of solid tumors including melanoma, glioma, and astrocytoma. TMZ exerts its effects mainly via the mutagenic product O(6)-methylguanine, a cytotoxic DNA lesion. This damage may be repaired by the DNA repair enzyme O(6)-methylguanine DNA methyltransferase (MGMT), a key player in the resistance of cancers to TMZ. Several strategies are presently being pursued to improve the killing of tumor cells by TMZ, with inhibition of MGMT being the most promising. In this review, we provide an overview of recent advances in this field.

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Osteoporosis is one of the most prevailing orthopedic diseases that causes a heavy burden on public health. Given that bone marrow‐derived mesenchymal stem cells (BMSCs) are of immense importance in osteoporosis development, it is necessary to expound the mechanisms underlying BMSC osteoblastic differentiation. Although mounting research works have investigated the role of small nucleolar RNA host gene 5 (SNHG5) in various diseases, elucidations on its function in osteoporosis are still scarce. It was observed that SNHG5 and RUNX family transcription factor 3 (RUNX3) were remarkably elevated during osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs). Further, we disclosed that the silencing of SNHG5 suppressed osteogenic differentiation and induced apoptosis of hBMSCs. What's more, SNHG5 acted as a competing endogenous RNA to affect RUNX3 expression via competitively binding with microRNA (miR)‐582‐5p. RUNX3 was also confirmed to simulate the transcriptional activation of SNHG5. Finally, our findings manifested that the positive feedback loop of SNHG5/miR‐582‐5p/RUNX3 executed the promoting role in the development of osteoporosis, which shed light on specific molecular mechanism governing SNHG5 in osteogenic differentiation and apoptosis of hBMSCs and indicated that SNHG5 may represent a novel target for the improvement of osteoporosis therapy.

Ras homolog gene family member A (RhoA) has been identified as a critical regulator of tumor aggressive behavior. In this study, we assessed the role of RhoA in the mechanisms underlying growth, migration, and invasion of squamous cell carcinoma of tongue (TSCC). Stable RhoA knockdown of TSCC cell lines SCC-4 and CAL27 were achieved using Lentiviral transfection. The effects of RhoA depletion on cell migration, invasion, and cell proliferation were determined. The possible underlying mechanism of RhoA depletion on TSCC cell line was also evaluated by determining the expression of Galectin-3 (Gal-3), β-catenin, and matrix metalloproteinase-9 (MMP-9) in vivo. Meanwhile, the underlying mechanism of TSCC growth was studied by analysis of cyclin D1/2, p21CIP1/WAF1, and p27Kip1 protein levels. Immunohistochemical assessments were performed to further prove the alteration of Gal-3 and β-catenin expression. We found that, in mice injected with human TSCC cells in the tongue, RhoA levels were higher in primary tumors and metastasized lymph nodes compared with those in the normal tissues. Silencing of RhoA significantly reduced the tumor growth, decreased the levels of Gal-3, β-catenin, MMP-9, and cyclin D1/2, and increased the levels of p21CIP1/WAF1 and p27Kip1. In vitro, RhoA knockdown also led to inhibition of cell migration, invasion, and proliferation. Our data suggest that RhoA plays a significant role in TSCC progression by regulating cell migration and invasion through Wnt/β-catenin signaling pathway and cell proliferation through cell cycle regulation, respectively. RhoA might be a novel therapeutic target of TSCC.

Periodontitis is a common disease that is difficult to treat, and if not controlled in time, it causes severe conditions, such as alveolar bone resorption and tooth loosening and loss. Periodontal ligament stem cells constitute a promising cell source for regenerative treatment of periodontitis due to their high osteogenic differentiation capacity. PDLSC osteogenesis plays a central role in periodontal regeneration through successive cytokine-mediated signaling pathways and various biochemical and physicochemical factors. However, this process is inhibited in the inflammatory periodontitis environment due to high concentrations of lipopolysaccharide. Here, we review the mechanisms that influence the osteogenic differentiation of periodontal stem cells in this inflammatory microenvironment.

Background Galectin-3 (Gal-3), the only chimeric β-galactosides-binding lectin, consists of Gal-3N (N-terminal regulatory peptide) and Gal-3C (C-terminal carbohydrate-recognition domain). Interestingly, Gal-3C could specifically inhibit endogenous full-length Gal-3 to exhibit anti-tumor activity. Here, we aimed to further improve the anti-tumor activity of Gal-3C via developing novel fusion proteins. Methods PK5 (the fifth kringle domain of plasminogen) was introduced to the N-terminus of Gal-3C via rigid linker (RL) to generate novel fusion protein PK5-RL-Gal-3C. Then, we investigated the anti-tumor activity of PK5-RL-Gal-3C in vivo and in vitro by using several experiments, and figured out their molecular mechanisms in anti-angiogenesis and cytotoxicity to hepatocellular carcinoma (HCC). Results Our results show that PK5-RL-Gal-3C can inhibit HCC both in vivo and in vitro without obvious toxicity, and also significantly prolong the survival time of tumor-bearing mice. Mechanically, we find that PK5-RL-Gal-3C inhibits angiogenesis and show cytotoxicity to HCC. In detail, HUVEC-related and matrigel plug assays indicate that PK5-RL-Gal-3C plays an important role in inhibiting angiogenesis by regulating HIF1α/VEGF and Ang-2 both in vivo and in vitro. Moreover, PK5-RL-Gal-3C induces cell cycle arrest at G1 phase and apoptosis with inhibition of Cyclin D1, Cyclin D3, CDK4, and Bcl-2, but activation of p27, p21, caspase-3, -8 and -9. Conclusion Novel fusion protein PK5-RL-Gal-3C is potent therapeutic agent by inhibiting tumor angiogenesis in HCC and potential antagonist of Gal-3, which provides new strategy for exploring novel antagonist of Gal-3 and promotes their application in clinical treatment.

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