HOTAIR/miR-1277-5p/ZEB1 axis mediates hypoxia-induced oxaliplatin resistance via regulating epithelial-mesenchymal transition in colorectal cancer.

The hypoxic microenvironment contributes to the chemoresistance of many malignant tumors including colorectal cancer (CRC). Accumulating studies have indicated that long non-coding RNAs (lncRNAs) play important roles in chemotherapy resistance. In this study, we aimed to determine the effect of lncRNAs in hypoxia-mediated resistance in CRC and its potential mechanism. Here, we discovered that hypoxia-induced oxaliplatin resistance and HOX transcript antisense RNA (HOTAIR) expression was increased in hypoxia-treated CRC cell lines and CRC tumors. Knockdown of HOTAIR by siRNA reduced the viability and proliferation of CRC cells treated with oxaliplatin and reversed hypoxia-induced resistance. Mechanically, we found that HOTAIR modulates zinc finger E-box binding homeobox 1 (ZEB1) expression by negative regulations of miR-1277-5p. When miR-1277-5p was silenced, knockdown of HOTAIR was unable to reduce the oxaliplatin resistance in CRC cells. In mouse models of CRC, HOTAIR knockdown markedly inhibited the tumor growth when treated with oxaliplatin. Thus, HOTAIR/miR-1277-5p/ZEB1 axis appears a promising therapeutic target for improving the oxaliplatin efficacy in CRC.

Efficacy of Pyrotinib in a Heavily Pretreated Patient with Lung Adenocarcinoma Harboring HER2 Amplification and Exon 20 Insertions: A Case Report.

The clinical benefits of HER2 inhibitors in patients with non-small cell lung cancer (NSCLC) have been limited. There is a paucity of effective therapies in NSCLC after developing resistance to initial anti-HER2 therapy. Herein, we presented the clinical benefit of pyrotinib in a 53-year-old patient with advanced lung adenocarcinoma whose circulating tumor DNA (ctDNA) analysis of pleural effusion revealed the coexistence of HER2 exon 20 p.Y772_A775dup (mutation ratio: 38.86%) and HER2 amplification (copy number: 4.5) following failures of multiple therapies including afatinib and ado-trastuzumab emtansine (T-DM1). Notably, pyrotinib treatment induced rapid and marked improvement of clinical symptoms, and partial response was observed after 8 weeks. CtDNA monitoring during the treatment showed that the mutation ratio of HER2 decreased to 7.99%, and the amplification disappeared. The patient achieved a progression-free survival of 7.5 months after treatment with pyrotinib. Thus, pyrotinib may be a new treatment strategy for the subgroup of lung adenocarcinoma patients, with coexistence of HER2 exon 20 p.Y772_A775dup and HER2 amplification even after failures of multiple anti-HER2 therapies. It also indicated the value of capture-based next-generation sequencing to monitor and guide therapy.