Paclitaxel is one of the most effective chemotherapy drugs for advanced cervical cancer. However, acquired resistance of paclitaxel represents a major barrier to successful anticancer treatment. In this study, paclitaxel-resistant HeLa sublines (HeLa-R cell lines) were established by continuous exposure and increased autophagy level was observed in HeLa-R cells. 3-Methyladenine or ATG7 siRNA, autophagy inhibitors, could restore sensitivity of HeLa-R cells to paclitaxel compared with parental HeLa cells. To determine the underlying molecular mechanism, differentially expressed proteins between HeLa and HeLa-R cells were identified by two-dimensional gel electrophoresis coupled with electrospray ionization quadrupole time-of-flight MS/MS. We found glycolysis-associated proteins were upregulated in HeLa-R cell lines. Inhibition of glycolysis by 2-deoxy-D-glucose or koningic acid could decrease autophagy and enhance sensitivity of HeLa-R cells to paclitaxel. Moreover, glycolysis could activate HIF1-α. Downregulation of HIF1-α by specific siRNA could decrease autophagy and resensitize HeLa-R cells to paclitaxel. Taken together, a possible Warburg effect activated HIF1-α-mediated signaling-induced autophagic pathway is proposed, which may provide new insight into paclitaxel chemoresistance.

14-3-3 proteins regulate many cellular processes that are implicated in cancer development, and the seven 14-3-3 isoforms have different expression level and isoform-specific roles in different tumors. However, the biological functions of 14-3-3 proteins and their correlations with renal carcinoma have not been investigated so far. In our study, the expression profiles and functional characterization of 14-3-3 proteins were discovered by a sensitive stable isotope labeling with amino acids in cell culture based quantitative proteomics analysis in human renal carcinoma tissues. We found that 14-3-3epsilon was up-regulated with 1.44-fold changes in renal cancerous tissues compared with that in counterpart kidney tissues, and 14-3-3sigma was almost not detected in both tissues due to its DNA highly methylated in our previous reports. The other five isoforms almost have similar expression level in two states of renal tissues. The following RT-PCR, Western blot and immunohistochemistry analysis for specific 14-3-3 isoform expression were all consistent with the quantitative proteomic data. Furthermore, the overexpression of 14-3-3epsilon in vitro can limitedly prompt the abnormal growth of renal tumor cells.

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Lung cancer is the leading cause of cancer-related death in the world. Non-small cell lung carcinomas (Non-SCLC) account for almost 80% of lung cancers, of which 40% were adenocarcinomas. For a better understanding of the molecular mechanisms behind the development and progression of lung cancer, particularly lung adenocarcinoma, we have used proteomics technology to search for candidate prognostic and therapeutic targets in pulmonary adenocarcinoma. The protein profile changes between human pulmonary adenocarcinoma tissue and paired surrounding normal tissue were analyzed using two-dimensional polyacrylamide gel electrophoresis (2-DE) based approach. Differentially expressed protein-spots were identified with ESI-Q-TOF MS/MS instruments. As a result, thirty two differentially expressed proteins (over 2-fold, p<0.05) were identified in pulmonary adenocarcinoma compared to normal tissues. Among them, two proteins (PKM2 and cofilin-1), significantly up-regulated in adenocarcinoma, were selected for detailed analysis. Immunohistochemical examination indicated that enhanced expression of PKM2 and cofilin-1 were correlated with the severity of epithelial dysplasia, as well as a relatively poor prognosis. Knockdown of PKM2 expression by RNA interference led to a significant suppression of cell growth and induction of apoptosis in pulmonary adenocarcinoma SPC-A1 cells in vitro, and tumor growth inhibition in vivo xenograft model (P<0.05). In addition, the shRNA expressing plasmid targeting cofilin-1 significantly inhibited tumor metastases and prolonged survival in LL/2 metastatic model. While additional works are needed to elucidate the biological significance and molecular mechanisms of these altered proteins identified in this study, PKM2 and cofilin-1 may serve as potential diagnostic and prognostic biomarkers, as well as therapeutic targets for pulmonary adenocarcinoma.