Conditional reprogramming: next generation cell culture

Long-term primary culture of mammalian cells has been always difficult due to unavoidable senescence. Conventional methods for generating immortalized cell lines usually require manipulation of genome which leads to change of important biological and genetic characteristics. Recently, conditional reprogramming (CR) emerges as a novel next generation tool for long-term culture of primary epithelium cells derived from almost all origins without alteration of genetic background of primary cells. CR co-cultures primary cells with inactivated mouse 3T3-J2 fibroblasts in the presence of RHO-related protein kinase (ROCK) inhibitor Y-27632, enabling primary cells to acquire stem-like characteristics while retain their ability to fully differentiate. With only a few years' development, CR shows broad prospects in applications in varied areas including disease modeling, regenerative medicine, drug evaluation, drug discovery as well as precision medicine. This review is thus to comprehensively summarize and assess current progress in understanding mechanism of CR and its wide applications, highlighting the value of CR in both basic and translational researches and discussing the challenges faced with CR.

Repurposing vitamin D for treatment of human malignancies targeting tumor microenvironment

Tumor cells along with a small proportion of cancer stem cells exist in a stromal microenvironment consisting of vasculature, cancer-associated fibroblasts, immune cells and extracellular components. Recent epidemiological and clinical studies strongly support that vitamin D supplementation is associated with reduced cancer risk and favorable prognosis. Experimental results suggest that vitamin D not only suppresses cancer cells, but also regulates tumor microenvironment to facilitate tumor repression. In this review, we have outlined the current knowledge on epidemiological studies and clinical trials of vitamin D. Notably, we summarized and discussed the anticancer action of vitamin D in cancer cells, cancer stem cells and stroma cells in tumor microenvironment, providing a better understanding of the role of vitamin D in cancer. We presently re-propose vitamin D to be a novel and economical anticancer agent.

Evaluation and SAR analysis of the cytotoxicity of tanshinones in colon cancer cells / 中国天然药物

AIM@#This study was designed to evaluate the anti-cancer actions of tanshinone I and tanshinone IIA, and six derivatives of tanshinone IIA on normal and cancerous colon cells. Structure activity relationship (SAR) analysis was conducted to delineate the significance of the structural modifications of tanshinones for improved anti-cancer action.@*METHOD@#Tanshinone derivatives were designed and synthesized according to the literature. The cytotoxicity of different compounds on colon cancer cells was determined by the MTT assay. Apoptotic activity of the tanshinones was measured by flow cytometry (FCM).@*RESULTS@#Tanshinone I and tanshinone IIA both exhibited significant cytotoxicity on colon cancer cells. They are more effective in p53(+/+) colon cancer cell line. It was also noted that the anti-cancer activity of tanshinone I was more potent and selective. Two of the derivatives of tanshinone IIA (N1 and N2) also exhibited cytotoxicity on colon cancer cells.@*CONCLUSION@#The anti-colon cancer activity of tanshinone I was more potent and selective than tanshinone IIA, and is p53 dependent. The derivatives obtained by structural modifications of tanshinone IIA exhibited lower cytotoxicity on both normal and colon cancer cells. From steric and electronic characteristics point of view, it was concluded that structural modifications of ring A and furan or dihydrofuran ring D on the basic structure of tanshinones influences the activity. An increase of the delocalization of the A and B rings could enhance the cytotoxicity of such compounds, while a non-planar and small sized D ring region would provide improved anti-cancer activity.

Cisplatin induces drug resistance in human esophageal squamous carcinoma cell line EC109 by decreasing CTR1 protein expression / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the mechanism of the development of cisplatin resistance in a human esophageal squamous carcinoma cell line.</p><p><b>METHODS</b>The cytotoxicity of cisplatin in the cisplatin-resistant resistant cell line EC109/CDDP and its parental cell line EC109 was measured by MTT assay. Whole-cell cisplatin accumulation and Pt-DNA adduct formation were determined by inductively coupled plasma mass spectrometry (ICP-MS). Western blotting was used to investigate the protein expression of full length PARP, cleaved PARP, and copper transporter 1 (CTR1).</p><p><b>RESULTS</b>EC109/CDDP cells was more resistant to cisplatin-induced cytotoxicity and apoptosis than EC109 cells. Compared with EC109 cells, EC109/CDDP cells exhibited less cisplatin accumulation and Pt-DNA adduct formation with also decreased CTR1 protein expression.</p><p><b>CONCLUSION</b>Cisplatin induces drug resistant phenotype by decreasing the protein level of CTR1, which controls cell accumulation and cytotoxic effect of cisplatin.</p>

Epidermal growth factor stimulates the proliferation of human esophageal squamous cell carcinoma HKESC-1 cells by increasing COX-2 expression / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the mechanisms responsible for epidermal growth factor (EGF)-induced proliferation of human esophageal squamous cell carcinoma cells.</p><p><b>METHODS</b>(3)H-thymidine incorporation assay was used to assess the proliferation of HKESC-1 cells exposed to EGF stimulation. Enzyme immunoassay was used to measure PGE(2) release from HKESC-1 cells, and the protein levels of cyclooxygenase 1 (COX-1), COX-2, EP1 and EP2 in EGF-stimulated cells were determined by Western blotting.</p><p><b>RESULTS</b>EGF upregulated COX-2 protein expression but produced no obvious effect on COX-1 protein expression in HKESC-1 cells. As a consequence of increased COX-2, EGF further enhanced cellular PGE(2) release. EGF stimulation also resulted in increased protein expression of EP2, a subtype of PGE(2) receptors. Both the non-selective COX inhibitor indomethacin and the selective COX-2 inhibitor SC-236 completely abolished EGF-induced PGE(2) release, and suppressed the mitogenic effect of EGF.</p><p><b>CONCLUSION</b>EGF stimulates the proliferation of HKESC-1 cells by increasing COX-2 protein expression and PGE(2) release. Upregulated EP2 protein expression may further amplify the mitogenic action of PGE(2).</p>