In vivo growth of subclones derived from Lewis lung carcinoma is determined by the tumor microenvironment.

Heterogeneity is a fundamental feature of human tumors and plays a major role in drug resistance and disease progression. In the present study, we selected single-cell-derived cell lines (SCDCLs) derived from Lewis lung carcinoma (LLC1) cells to investigate tumorigenesis and heterogeneity. SCDCLs were generated using limiting dilution. Five SCDCLs were subcutaneously injected into wild-type C57BL/6N mice; however, they displayed significant differences in tumor growth. Subclone SCC1 grew the fastest in vivo, whereas it grew slower in vitro. The growth pattern of SCC2 was the opposite to that of SCC1. Genetic differences in these two subclones showed marked differences in cell adhesion and proliferation. Pathway enrichment results indicate that signal transduction and immune system responses were the most significantly altered functional categories in SCC2 cells compared to those in SCC1 cells in vitro. The number and activation of CD3+ and CD8+ T cells and NK cells in the tumor tissue of tumor-bearing mice inoculated with SCC2 were significantly higher, whereas those of myeloid cells were significantly lower, than those in the SCC1 and LLC1 groups. Our results suggest that the in vivo growth of two subclones derived from LLC1 was determined by the tumor microenvironment rather than their intrinsic proliferative cell characteristics.

Three adiponectin rs1501299G/T, rs822395A/C, and rs822396A/G polymorphisms and risk of cancer development: a meta-analysis.

Many epidemiological studies have studied the associations between adiponectin rs1501299G/T, rs822395A/C, and rs822396A/G polymorphisms and risk of cancer development, while conflicting results have been reported. Therefore, we conducted a meta-analysis to assess the associations. We retrieved the following databases: Medline, Embase, Web of Science, and Wanfang, and the latest update date was 15th of August 2012. Odds ratio (OR) and corresponding 95 % confidence interval (95 % CI) were calculated by using fixed- or random-effect model. Overall, there were 13 case-control studies consisting of 7,902 subjects for adiponectin rs1501299G/T, seven studies consisting of 6,209 subjects for rs822395A/C, and seven studies consisting of 5,791 subjects for rs822396A/G polymorphism in this study. Combined analyses indicated that neither adiponectin rs822395A/C nor rs822396A/G was associated with risk of cancer incidence (OR (95 % CI) 0.91 (0.77-1.77), P z test = 0.26 for CC vs. AA and 0.96 (0.87-1.05) for C carriers vs. A carriers, P z test = 0.33 for rs822395A/C; 0.88 (0.53-1.47) for GG vs. AA, P z test = 0.63 and 0.94 (0.84-1.04) for G carriers vs. A carriers, P z test = 0.24 for rs822396A/G polymorphism). Similarly, combined analysis also indicated that adiponectin rs1501299G/T polymorphism was not associated with risk of cancer development (OR (95 % CI) 0.86 (0.73-1.01) for TT vs. GG, P z test = 0.07 and 1.17 (0.98-1.39), P z test = 0.08). However, when stratified analyses were conducted, the result indicated that T allele was significantly associated with increased cancer risk for Caucasians (OR (95 % CI) 1.28 (1.06-1.64) and P z test = 0.01 for G carriers vs. T carriers) and associated with increased risk of colorectal cancer development while with decreased risk of prostate cancer incidence compared to G allele (OR (95 % CI) 1.34 (1.14-1.57), P z test < 0.01 for G carriers vs. T carriers for colorectal cancer; 0.80 (0.65-0.97), P z test = 0.03 for TG vs. GG for prostate cancer). In summary, this meta-analysis indicated that adiponectin rs1501299G/T, rather than rs822395A/C and rs822396A/G polymorphism, was associated with risk of cancer development, especially for colorectal and prostate cancer.

Cancer stem-like side population cells in the human nasopharyngeal carcinoma cell line cne-2 possess epithelial mesenchymal transition properties in association with metastasis.

It has been recently reported that side population (SP) cells in nasopharyngeal carcinoma (NPC) cell lines display characteristics of cancer stem-like cells. However, the biological behavior and the significance of these cells for NPC progression remain unclear. In this study, we isolated SP cells from the NPC cell line CNE-2 by flow cytometry and investigated their biological characteristics. We discovered that SP cells had stronger colony forming abilities compared to the non-side population (NSP) cells, and observed that some SP cells looked more like the shape of mesenchymal cells when cultured in the common polyHEMA-coated flask. When checked by quantitative real-time PCR, the SP cells expressed higher levels of stemness-related genes Oct4, Sox2 and Nanog, and mesenchymal cell-related genes N-cadherin, vimentin and Snail, while they expressed lower levels of the epithelial cell-related gene, E-cadherin. Western blot and immunofluorescence staining methods further verified that SP cells expressed higher vimentin and expressed lower E-cadherin levels. Finally, Transwell invasion assay results indicated that the SP cells had higher invasive potential compared to NSP cells. Collectively, our data reveal that SP cells in the CNE-2 cell line not only possess the properties of cancer stem cells, but also have more mesenchymal cell characteristics which are associated with epithelial mesenchymal transition (EMT) and cancer cell invasion and metastasis. These findings are helpful for developing novel targets for effective clinical treatment of NPC.

Dynamic distribution and expression in vivo of human endostatin gene delivered by adenoviral vector.

Endostatin, a 20-kDa carboxyl-terminal fragment of collagen XVIII, is a potent inhibitor of endothelial cell proliferation and tumor angiogenesis. We have constructed replication-deficient recombinant adenovirus (Ad-rhE), which encoded secreted human endostatin, and our previous studies showed that Ad-rhE had a potent suppression of tumor growth in vivo. In the present study, we investigated the dynamic distribution and expression of human endostatin gene in vivo using fluorogenic real-time quantitative PCR and enzyme-linked immunosorbent assay(ELISA), respectively, with an injection of 2.0 x10(9)pfu of Ad-rhE. After injection, the Ad-rhE DNAs decreased sharply, but lasted a relative long-term at low concentration (10,000--20,000 copies/mg tissues). Whereas the expressed endostatin rose up rapidly, and reached to the top on day 5 after injection of Ad-rhE, and then decreased sharply, but endostatin in tumors sustained to over 9 days at a certain level. Both Ad-rhE DNAs and endostatin mainly enriched in tumors in vivo, and then in livers. These results suggest that endostatin gene delivered by adenoviral vector can generate a high expression in vivo, and both the metabolism pathways of Ad-rhE DNAs and endostatin in vivo are through the systems of livers.

[Research advancement of endogenous angiogenesis inhibitors].

Angiogenesis is required for invasive tumor growth and metastasis. Inhibition of angiogenesis is considered to be a promising approach of antitumor therapy. Recently, many endogenous angiogenesis inhibitors have been discovered, some of them are currently in various stages of clinical trials. This review focused on the structure, function, and mechanism of endogenous angiogenesis inhibitors, and their potential in treating tumor.