Aberrant expression of microRNA-146a (miR-146a) has been reported to be involved in the development and progression of various types of cancers. However, its role in non-small cell lung cancer (NSCLC) has not been elucidated. The aim of this study was to investigate the contribution of miR-146a to various aspects of the malignant phenotype of human NSCLCs. In functional experiments, miR-146a suppressed cell growth, induced cellular apoptosis and inhibited EGFR downstream signaling in five NSCLC cell lines (H358, H1650, H1975, HCC827 and H292). miR-146a also inhibited the migratory capacity of these NSCLC cells. On the other hand, miR-146a enhanced the inhibition of cell proliferation by drugs targeting EGFR, including both TKIs (gefitinib, erlotinib, and afatinib) and a monoclonal antibody (cetuximab). These effects were independent of the EGFR mutation status (wild type, sensitizing mutation or resistance mutation), but were less potent compared to the effects of siRNA targeting of EGFR. Our results suggest that these effects of miR-146a are due to its targeting of EGFR and NF-κB signaling. We also found, in clinical formalin fixed paraffin embedded (FFPE) lung cancer samples, that low expression of miR-146a was correlated with advanced clinical TNM stages and distant metastasis in NSCLC (P<0.05). The patients with high miR-146a expression in their tumors showed longer progression-free survival (25.6 weeks in miR-146a high patients vs. 4.8 weeks in miR-146a low patients, P<0.05). miR-146a is therefore a strong candidate prognostic biomarker in NSCLC. Thus inducing miR-146a might be a therapeutic strategy for NSCLC.

Cetuximab was well tolerated but had limited activity in this patient population with progressive HGG. A minority of patients may derive a more durable benefit but were not prospectively identified by EGFR gene copy number.

Receptor tyrosine kinase signaling causes profound neo-angiogenesis in high-grade gliomas (HGG). The KIT, PDGFR-α, and VEGFR2 genes are frequently amplified and expressed in HGG and are molecular targets for therapeutic inhibition by the small-molecule kinase inhibitor sunitinib malate. Twenty-one patients with progressive HGG after prior radiotherapy and chemotherapy received a daily dose of 37.5 mg sunitinib until progression or unacceptable toxicity. Magnetic resonance imaging (MRI) and dynamic susceptibility contrast (DSC)-enhanced perfusion measurements were performed before and during therapy. Cerebral blood volume (CBV) and cerebral blood flow (CBF) lesion-to-normal-white matter ratios were measured to evaluate the antiangiogenic effects of sunitinib. The most frequent grade ≥3 adverse events were skin toxicity, neutropenia, thrombocytopenia, and lymphocytopenia. None of the patients achieved an objective response, whereas a decrease in CBV and CBF within the lesion compared with the normal brain was documented in four out of 14 (29%) patients evaluable for DSC-enhanced perfusion measurements. All patients experienced progression of their disease before or after eight weeks of therapy. Median time-to-progression and overall survival were 1.6 (95%CI 0.8-2.5) and 3.8 (95% CI 2.2-5.3) months, respectively. No correlation could be established between VEGFR2, PDGFR-α, and KIT gene copy numbers or protein expression and the effects of sunitinib. Single-agent sunitinib at 37.5 mg/day had insufficient activity to warrant further investigation of this monotherapy regimen in recurrent HGG.

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