Background/Aims: Periostin is upregulated in non-small cell lung cancer (NSCLC). This study was done to explore the function of periostin in the development of cisplatin (CDDP) resistance in NSCLC. Methods: The effects of overexpression or knockdown of periostin on CDDP sensitivity was examined in A549 cells. The involvement of signal transducer and activator of transcription 3 (Stat3) and Akt signaling in the action of periostin was checked. The in vivo effect of periostin silencing on CDDP susceptibility was determined in a mouse xenograft model. Results: Periostin was significantly upregulated in CDDP-resistant A549 cells, compared to parental controls. Overexpression of periostin rendered A549 cells more resistant to CDDP-induced apoptosis and enhanced Stat3 and Akt phosphorylation and survivin expression. Periostin-mediated protection against CDDP-induced apoptosis was compromised by downregulation of survivin. Furthermore, knockdown of periostin re-sensitized CDDP-resistant A549 cells to CDDP. After CDDP treatment, greater volume reduction was observed in periostin-silenced xenograft tumors than in control tumors, which was accompanied by reduced levels of phosphorylated Stat3 and survivin in periostin-depleted tumors. Conclusion: In conclusion, periostin promotes CDDP resistance in NSCLC cells largely through activation of Stat3 and Akt and upregulation of survivin and thus represents a promising target for overcoming CDDP resistance.
Abstract.Increasing evidence has shown that microRNA (miRNA) is extensively involved in the pathophysiology of lung cancer. Microarray data demonstrated the increasing levels of miR-19a in the peripheral blood from patients suffering from lung cancer, which is closely associated with poor prognosis of lung cancer. However, the underlying molecular mechanism of miR-19a remains to be determined. The results of the present study showed a higher expression of miR-19a compared with normal bronchial epithelial cells. Furthermore, lentivirus vectors were constructed to establish cell lines that over expressed and knocked out miR-19a in order to study the role of miR-19a on the metastasis and proliferation of lung cancer cells. Investigation into the underlying mechanism of miR-19a, revealed that MXD1 may be the key gene targeting miR-19a, participating in the process of proliferation and metastasis of lung cancer cells.
Accumulation of single nucleotide polymorphisms (SNPs) in the displacement loop (D-loop) of mitochondrial DNA (mtDNA) may be associated with an increased cancer risk. We investigated the lung cancer risk profile of D-loop SNPs in a case-controlled study. The minor alleles of nucleotides 235A/G and 324A/G were associated with an increased risk for lung cancer patients. The minor alleles of the nucleotides 151C/T, 200A/G, 524C/CA, and 16274G/A were specifically associated with the cancer risk of squamous cell carcinoma, whereas the minor allele of nucleotide 16298T/C was specifically associated with the risk of small cell lung cancer. In conclusion, SNPs in mtDNA are potential modifiers of lung cancer risk. The analysis of genetic polymorphisms in the mitochondrial D-loop can help identify subgroups of patients who are at a high risk of developing lung cancer.
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