Description: Purpose: This study was performed to identify the detailed mechanisms by which miR-296-3p functions as a tumor suppressor to prevent lung adenocarcinoma (LADC) cell growth, metastasis, and chemoresistance. Experimental Design: The miR-296-3p expression was examined by real-time PCR and in situ hybridization. MTT, EdU incorporation, Transwell assays, and MTT cytotoxicity were respectively performed for cell proliferation, metastasis, and chemoresistance; Western blotting was performed to analyze the pathways by miR-296-3p and HDGF/DDX5 complex. The miRNA microarray and luciferase reporter assays were respectively used for the HDGF-mediated miRNAs and target genes of miR-296-3p. The ChIP, EMSA assays, and coimmunoprecipitation combined with mass spectrometry and GST pull-down were respectively designed to analyze the DNA–protein complex and HDGF/DDX5/β-catenin complex. Results: We observed that miR-296-3p not only controls cell proliferation and metastasis, but also sensitizes LADC cells to cisplatin (DDP) in vitro and in vivo . Mechanistic studies demonstrated that miR-296-3p directly targets PRKCA to suppress FAK–Ras-c–Myc signaling, thus stimulating its own expression in a feedback loop that blocks cell cycle and epithelial–mesenchymal transition (EMT) signal. Furthermore, we observed that suppression of HDGF–β-catenin–c-Myc signaling activates miR-296-3p, ultimately inhibiting the PRKCA–FAK–Ras pathway. Finally, we found that DDX5 directly interacts with HDGF and induces β-catenin–c-Myc, which suppresses miR-296-3p and further activates PRKCA–FAK–Ras, cell cycle, and EMT signaling. In clinical samples, reduced miR-296-3p is an unfavorable factor that inversely correlates with HDGF/DDX5, but not PRKCA. Conclusions: Our study provides a novel mechanism that the miR-296-3p–PRKCA–FAK–Ras–c-Myc feedback loop modulated by HDGF/DDX5/β-catenin complex attenuates cell growth, metastasis, and chemoresistance in LADC. Clin Cancer Res; 23(20); 6336–50. ©2017 AACR .

Description: Purpose: This study was implemented to investigate the associations between SNP in mature microRNA (miRNA) sequence and lung cancer prognosis and to verify the function of those SNP. Experimental Design: Eight SNPs (rs3746444T〉C in hsa-mir-499, rs4919510C〉G in hsa-mir-608, rs13299349G〉A in hsa-mir-3152, rs12220909G〉C in hsa-mir-4293, rs2168518G〉A in hsa-mir-4513, rs8078913T〉C in hsa-mir-4520a, rs11237828T〉C in hsa-mir-5579, and rs9295535T〉C in hsa-mir-5689) were analyzed in a southern Chinese population with 576 patients with lung cancer, and the significant results were validated in two additional cohorts of 346 and 368 patients, respectively. A series of experiments were performed to evaluate the relevancies of those potentially functional SNPs. Results: We found that the microRNA-499 rs3746444T〉C polymorphism exhibited a consistently poor prognosis for patients with lung cancer in the discovery set [HR, 1.24; 95% confidence interval (CI), 1.02–1.49; P = 0.028], in the validation set I (HR, 1.31; 95% CI, 1.01–1.71; P = 0.048) and in the validation set II (HR, 1.45; 95% CI, 1.12–1.86; P = 0.004). The adverse effect of CT/CC variants was more remarkable in patients receiving platinum-based chemotherapy. Further functional assays demonstrated that the rs3746444C variant allele influences the expression of several cancer-related genes and affects lung cancer cells' proliferation and tumor growth in vivo and in vitro via the cisplatinum resistance. Conclusion: Our findings suggested that the rs3746444T〉C polymorphism in mature miR-499 sequence could contribute to poor prognosis by modulating cancer-related genes' expression and thus involve tumorigenesis and anti-chemotherapy, which may be a useful biomarker to predict lung cancer patients' prognosis. Clin Cancer Res; 21(7); 1602–13. ©2015 AACR .

Description: Contributions of the tumor microenvironment (TME) to progression in thyroid cancer are largely unexplored and may illuminate a basis for understanding rarer aggressive cases of this disease. In this study, we investigated the relationship between the TME and thyroid cancer progression in a mouse model where thyroid-specific expression of oncogenic BRAF and loss of Pten (BrafV600E/Pten−/−/TPO-Cre) leads to papillary thyroid cancers (PTC) that rapidly progress to poorly differentiated thyroid cancer (PDTC). We found that fibroblasts were recruited to the TME of BrafV600E/Pten−/−/TPO-Cre thyroid tumors. Conditioned media from cell lines established from these tumors, but not tumors driven by mutant H-ras, induced fibroblast migration and proliferation in vitro. Notably, the extracellular matrix of BrafV600E/Pten−/−/TPO-Cre tumors was enriched with stromal-derived fibrillar collagen, compared with wild-type or Hras-driven tumors. Further, type I collagen enhanced the motility of BrafV600E/Pten−/−/TPO-Cre tumor cells in vitro. In clinical specimens, we found COL1A1 and LOX to be upregulated in PTC and expressed at highest levels in PDTC and anaplastic thyroid cancer. Additionally, increased expression levels of COL1A1 and LOX were associated with decreased survival in thyroid cancer patients. Overall, our results identified fibroblast recruitment and remodeling of the extracellular matrix as pivotal features of the TME in promoting thyroid cancer progression, illuminating candidate therapeutic targets and biomarkers in advanced forms of this malignancy. Cancer Res; 76(7); 1804–13. ©2016 AACR.