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Currently, chemoresistance is an important cause of treatment failure in colorectal cancer. Cancer stem cells, which are a population of multi-potent cells with the capacity to self-renew and differentiate, have been found to participate in chemoresistance. In the present study, the chemotherapeutic drug oxaliplatin induced autophagy in colorectal cancer cell lines, which in turn protected cancer cells from apoptosis. Further results showed that oxaliplatin-induced autophagy enriched the population of colorectal CSCs and participated in maintaining the stemness of colorectal CSCs, thus making the cells more resistant to chemotherapy. Taken together, the results indicate that autophagy might enhance the chemoresistance of colorectal cancer cells by protecting the stemness and chemoresistance of colorectal CSCs. Our study demonstrates that autophagy plays a pro-survival role in colorectal CSCs subjected to oxaliplatin. Therefore, targeting autophagy may be considered as a potential therapeutic strategy to address chemoresistance in the treatment of colorectal cancer.

Dysregulation of androgen-binding protein (ABP) is associated with a number of endocrine and andrology diseases. However, the ABP metabolism in Sertoli cells is largely unknown. We report that autophagy degrades ABP in rat Sertoli cells and the autophagic clearance of ABP is regulated by testosterone, which prolongs the ABP biological half-life by inhibiting autophagy. Further studies identified that the autophagic clearance of ABP might be selectively regulated by testosterone, independent of stress (hypoxia)-induced autophagic degradation. These data demonstrate that testosterone up-regulates ABP expression at least partially by suppressing the autophagic degradation. We report a novel finding with respect to the mechanisms by which ABP is cleared and by which the process is regulated in Sertoli cells.

Autophagy favors cell survival under hypoxia, and increasing evidence revealed that microRNAs regulate autophagy. We report here hypoxia increased the expression of miR-96 in prostate cancer cells, and miR-96 stimulated autophagy by suppressing MTOR. We found that inhibition of miR-96 abolished hypoxia-induced autophagy. Paradoxically, ectopic over-expression of miR-96 to a certain threshold, also abolished the hypoxia-induced autophagy. Further studies have shown that high levels of miR-96 inhibited autophagy through suppressing ATG7, a key autophagy-associated gene. Importantly, the miR-96 expression level threshold was determined, and the effects of miR-96 on autophagy on either side of the threshold were opposite. These data demonstrate hypoxia-induced autophagy is at least partially regulated by miR-96; miR-96 can promote or inhibit autophagy by principally inhibiting MTOR or ATG7 depending on the expression levels of miR-96. Our observation might reveal a novel regulatory mode of autophagy by microRNAs under hypoxia.

The tumor microenvironment, including ischemia, has been increasingly recognized as a critical factor in the process of tumor development. Hypoxia and nutrient deficiency resulting from ischemia widely exist in solid tumors. Recent studies have shown that hypoxia and nutrient deficiency contribute to chemoresistance by inducing autophagy, but the underlying mechanism remains unknown. This study aimed to explore the role of autophagy induced by low glucose and hypoxia (LH) in the chemoresistance of hepatocellular carcinoma cells. Our results demonstrated that LH induced autophagy and downregulated Bad and Bim in hepatocellular carcinoma cells. The inhibition of autophagy reversed the reduction of these pro-apoptotic factors during the LH treatment. Furthermore, Bad and Bim were also significantly downregulated by autophagy during the process that LH promoted the chemoresistance of hepatocellular carcinoma cells. In addition, RNAi or the overexpression of Bad and Bim can significantly reduce or increase chemotherapy-induced cell death, respectively. Taken together, these data indicate that the downregulation of Bad and Bim plays a significant role in the autophagy-induced chemoresistance of hepatocellular carcinoma cells.

Background Non-alcoholic fatty liver disease, one of the most common liver diseases, has obtained increasing attention. Palmitate (PA)-induced liver injury is considered a risk factor for the development of non-alcoholic fatty liver disease. Autophagy, a cellular degradative pathway, is an important self-defense mechanism in response to various stresses. In this study, we investigated whether autophagy plays a protective role in the progression of PA-induced hepatocytes injury. Results Annexin V-FITC/PI staining by FCM analysis, TUNEL assay and the detection of PARP and cleaved caspase3 expression levels demonstrated that PA treatment prominently induced the apoptosis of hepatocytes. Meanwhile, treatment of PA strongly induced the formation of GFP-LC3 dots, the conversion from LC3I to LC3II, the decrease of p62 protein levels and the increase of autophagosomes. These results indicated that PA also induced autophagy activation. Autophagy inhibition through chloroquine pretreatment or Atg5shRNA infection led to the increase of cell apoptosis after PA treatment. Moreover, induction of autophagy by pretreatment with rapamycin resulted in distinct decrease of PA-induced apoptosis. Therefore, autophagy can prevent hepatocytes from PA-induced apoptosis. In the further study, we explored pathway of autophagy activation in PA-treated hepatocytes. We found that PA activated PKCα in hepatocytes, and had no influence on mammalian target of rapamycin and endoplasmic reticulum stress pathways. Conclusions These results demonstrated that autophagy plays a protective role in PA-induced hepatocytes apoptosis. And PA might induce autophagy through activating PKCα pathway in hepatocytes.

Some biosamples obtained from biobanks may go through thawing before processing. We aim to evaluate the effects of thawing at room temperature for different time periods on gene expression analysis. A time course study with four time points was conducted to investigate the expression profiling on 10 thawed normal mice renal tissue samples through Affymetrix GeneChip mouse gene 2.0 st array. Microarray results were validated by quantitative real time polymerase chain reactions (qPCR) on 6 candidate reference genes and 11 target genes. Additionally, we used geNorm plus and NormFinder to identify the most stably expressed reference genes over time. The results showed RNA degraded more after longer incubation at room temperature. However, microarray results showed only 240 genes (0.91%) altered significantly in response to thawing at room temperature. The signal of majority altered probe sets decreased with thawing time, and the crossing point (Cp) values of all candidate reference genes correlated positively with the thawing time (p