BackgroundEpidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKI) have been widely used for the treatment of non-small cell lung cancer (NSCLC). KRAS and EGFR somatic mutations in NSCLC may predict resistance and responsiveness to TKI, respectively. Nevertheless, most research to date has been conducted on samples from primary tumors. For many patients with advanced disease, their samples can only be obtained from metastases for test. The molecular characteristics of metastasized tumors may be different from those of primary tumors.Materials and methodsMutation status of KRAS and EGFR between primary tumors and local lymph node metastases of 80 Chinese patients with NSCLC were analyzed by direct sequencing. Five of them were given gefitinib as neoadjunvant treatment after the EGFR-TKI sensitive mutations were detected in their biopsies of mediastinal lymph nodes metastases. McNemar's test was used to compare the EGFR and KRAS mutation status between primary tumors and corresponding local lymph node metastases. Data evaluation was carried out with SPSS_13.0 statistical software.ResultsAmong the 160 samples, one primary tumor and seven metastases were identified with KRAS mutations and 21 primary tumors and 26 metastases were found to have EGFR mutations. KRAS and EGFR mutation status was different between primary tumors and corresponding metastases in 6 (7.5%) and 7 (8.75%) patients, respectively. One patient with no TKI sensitive mutations detected in the primary tumor showed disease progression.ConclusionOur results suggest that a considerable proportion of NSCLC in Chinese population showed discrepancy in KRAS and EGFR mutation status between primary tumors and corresponding metastases. This observation may have important implication for the use of targeted TKI therapy in the treatment of NSCLC patients.

Our results suggest that p-STAT3 is an important factor during carcinogenesis and metastasis of lung carcinoma, and its relationship to EGFR mutation status may provide potential targeting opportunities in future therapies.

Abstract. Endoplasmic reticulum (ER) stress and autophagy have both been reported to be associated with lipotoxicity in β-cells, yet the relationship between them has not been fully clarified. In the present study, we tested the hypothesis that the ER stress-autophagic pathway in β-cells is a downstream pathway activated following saturated fatty acid treatment. Mouse insulinoma (MIN6) β-cells were treated with either palmitate or thapsigargin (TG) with or without various inhibitors. The results indicated that palmitate strongly enhanced the protein expression of microtubule-associated protein 1 light chain 3 (LC3)-II. Furthermore, the expression levels of ER stress markers, BiP and CHOP, and phosphorylation levels of JNK were increased after palmitate treatment. In addition, palmitate-induced autophagy was blocked by 500 µM of the ER stress inhibitor tauroursodeoxycholic acid (TUDCA) or 20 µM JNK inhibitor SP600125. In turn, the phosphorylation of Akt (Ser473) was also downregulated by palmitate, while the levels of insulin receptor β (IRβ) were not reduced. A further increase in LC3-II levels was observed in cells treated with both palmitate and 50 µM PI3K/Akt inhibitor LY294002 compared with cells treated with palmitate alone. Palmitate-induced phospho-Akt (Ser473) downregulation was also inhibited by TUDCA or SP600125. Pretreatment with the autophagy inhibitor 3-methyladenine (3-MA, 5 mM) for 1 h increased the expression of ER stress markers, and enhanced cell injuries caused by 0.1 µM TG, including decreased cell viability and insulin secretion. Palmitate induces autophagy in pancreatic β-cells possibly through activation of ER stress and its downstream JNK pathway. Palmitate-induced autophagy may protect β-cells against cell injuries caused by ER stress. IntroductionCell dysfunction induced by lipid accumulation or lipotoxicity in pancreatic β-cells may contribute to the pathogenesis of type 2 diabetes. In recent years, autophagy has been identified as a novel mechanism that regulates β-cell function (1-3) and death (4-6). Autophagy is a conserved self-digestion process among eukaryotes that regulates cellular component degradation through lysosomes. Autophagy plays an important role in maintaining cell homeostasis by regulating the synthesis, degradation and recycling of cellular components (7). A low level of constitutive autophagy exists in order to control the quality of proteins and organelles. Autophagy is important for survival as it reallocates nutrients to essential processes from less important ones (8). In addition, autophagy can also be induced under stress conditions to maintain the balance of the cell. Growing evidence (4,9) indicates that autophagy in β-cells is activated by free fatty acids, and suggests that addressing the underlying mechanisms involved in lipid-induced autophagy may provide clues for treating or preventing β-cell lipotoxicity.Free fatty acids are known as inducers of endoplasmic reticulum (ER) stress. Previous evidence has revealed that saturated fatty acid induces β-cell...

More and more studies indicate the relevance of miRNAs in inducing certain drug resistance. Our study aimed to investigate whether microRNA‐130b‐3p (miR‐130b) mediates the chemoresistance as well as proliferation of lung cancer (LC) cells. MTS assay and apoptosis analysis were conducted to determine cell proliferation and apoptosis, respectively. Binding sites were identified using a luciferase reporter system, whereas mRNA and protein expression of target genes was determined by RT‐PCR and immunoblot, respectively. Mouse xenograft model was used to evaluate the role of miR‐130b in cisplatin resistance in vivo. The rising level of miR‐130b in cisplatin resistance LC cell lines (A549/CR and H446/CR) versus its parental cell lines, indicated its crucial relevance for LC biology. We identified PTEN as miR‐130b's major target and inversely correlated with miR‐130b expression in LC. Moreover, excessive miR‐130b expression promoted drug resistance and proliferation, decreased apoptosis of A549 cells. Suppression of miR‐130b enhanced drug cytotoxicity and reduced proliferation of A549/CR cells both internally and externally. Particularly, miR‐130b mediated Wnt/β‐catenin signalling pathway activities, chemoresistance and proliferation in LC cell, which was partially blocked following knockdown of PTEN. These findings suggest that miR‐130b targets PTEN to mediate chemoresistance, proliferation, and apoptosis via Wnt/β‐catenin pathway. The rising level of miR‐130b in cisplatin resistance LC cell lines (A549/CR and H446/CR) versus its parental cell lines, indicated its crucial relevance for LC biology. Moreover, excessive miR‐130b expression promoted drug resistance and proliferation, decreased apoptosis of A549 cells. These findings suggest that miR‐130b targets PTEN to mediate chemoresistance, proliferation, and apoptosis via Wnt/β‐catenin pathway.

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