No abstract

Accumulating evidence shows that microRNAs (miRNAs) have a critical role in the initiation and progression of types of human cancer, including breast cancer. Recent research indicated that miRNAs are also related with the chemotherapy on cancers. In this study, the expression of miR-221 in breast cancer (BC) patients' serum and cancer tissues was found to be significantly up-regulated. The results of in vitro MTT assay indicated that although the anti-miR-221 oligonucleotide alone did not influence the viability of BC cell lines markedly, it significantly promoted the cytotoxicity of cisplatin (DDP) to BC cells. Mechanistic studies demonstrated that the gene of BIM (Bcl-2 interacting mediator of cell death), a pro-apoptotic Bcl-2 family protein, was up-regulated by the knockdown of miR-221. We found that the synergetic effect of anti-miR-221 on increasing the sensitivity of MDA-MB-231 was BIM dependant. Furthermore, results of immunoprecipitation showed the up-regulated BIM directly combined with the Bax and Bak, leading to mitochondrial dysfunction. Our results suggest the anti-miR-221 could promote the cisplatin-inducing apoptosis by targeting the Bim-Bax/Bak axis in breast cancer.

Papillary thyroid cancer (PTC) is the most frequent type of malignant thyroid cancer, but its molecular mechanisms remain unknown. To better understand the tumorigenesis and progression of PTC, we conducted a comprehensive analysis of the whole-transcriptome resequencing of paired PTC and normal thyroid tissues. Nectin cell adhesion molecule 4 (NECTIN4) was significantly overexpressed in thyroid carcinoma compared with that in matched normal tissue. We also assessed the relation between the expression level of NECTIN4 and the clinicopathological features of PTC in The Cancer Genome Atlas database, and results showed that upregulated NECTIN4 is associated with lymph node metastasis ( P <0.001) and tumor size ( P =0.017). The biological function of NECTIN4 was also investigated by using the PTC cell lines TPC-1 and KTC-1. In vitro experiments demonstrated that NECTIN4 downregulation significantly inhibits the colony formation, proliferation, migration, and invasion of PTC cell lines. NECTIN4 could modulate the expression of epithelial–mesenchymal transition-related proteins via the PI3K/AKT pathway, and SC79, an AKT phosphorylation activator, could reverse the si-RNA knockdown effect. In addition, after the use of AKT inhibitors (LY 294,002), we found that SiRNA have similar effect with AKT inhibitors. Taking the results together, the current study shows that NECTIN4 has important biological implications in the tumorigenesis and metastasis of PTC and may be a potential therapeutic target for the disease.

Background:Thyroid cancer is the most common endocrine system malignancy. Scientists have done considerable research into the molecular mechanisms involved, but many mechanisms remain undiscovered. Material/Methods:We performed a comprehensive analysis of the whole-transcriptome resequencing derived from thyroid tissues and paired papillary thyroid cancer (PTC) and showed that lysophosphatidic acid receptor 5 (LPAR5) is strongly overexpressed in thyroid carcinoma. Then, we used TPC-1 and KTC-1 to explore the effect of LPAR5 knockdown on colony formation, migration, proliferation, invasion, and apoptosis of PTC cell line cells. AKT activator was used for the recovery test. Finally, we designed proteomic experiments to explore the role of LPAR5 in the AKT pathway and the EMT process. Results:Cell function experiments showed that LPAR5 knockdown can significantly induce apoptosis of KTC-1 and TPC-1 cells. Furthermore, LPAR5 can promote PTC metastasis and tumorigenesis by activating the PI3K/AKT pathway and decreasing its cancer-promoting effect when using AKT agonist. We also found that LPAR5 can regulate the expression of EMT-related proteins, which affect invasion and migration. Conclusions:In summary, downregulation of LPAR5 expression can inhibit the physiological process of PTC, and this phenomenon is related to the PI3K/AKT pathway and EMT.

These results strongly suggest that PRL-3 expression can indicate the potential role of LNM to some extent. Increasing the risk of tumor metastasis (OR = 3.889). Our results also imply that PRL-3 might be a novel molecular marker for predicting relapse of invasive breast cancer.