[Development of New Molecular EZH2 on Lung Cancer Invasion and Metastasis]

HOXB13 networking with ABCG1/EZH2/Slug mediates metastasis and confers resistance to cisplatin in lung adenocarcinoma patients

Rationale: Distant metastasis and chemoresistance are the major causes of short survival after initial chemotherapy in lung adenocarcinoma patients. However, the underlying mechanisms remain elusive. Our pilot study identified high expression of the homeodomain transcription factor HOXB13 in chemoresistant lung adenocarcinomas. We aimed to investigate the role of HOXB13 in mediating lung adenocarcinoma chemoresistance.

Methods: Immunohistochemistry assays were employed to assess HOXB13 protein levels in 148 non-small cell lung cancer patients. The role of HOXB13 in lung adenocarcinoma progression and resistance to cisplatin therapy was analyzed in cells, xenografted mice, and patient-derived xenografts. Needle biopsies from 15 lung adenocarcinoma patients who were resistant to cisplatin and paclitaxel therapies were analyzed for HOXB13 and EZH2 protein levels using immunohistochemistry.

Results: High expression of HOXB13 observed in 17.8% of the lung adenocarcinoma patients in this study promoted cancer progression and predicted poor prognosis. HOXB13 upregulated an array of metastasis- and drug-resistance-related genes, including ABCG1, EZH2, and Slug, by directly binding to their promoters. Cisplatin induced HOXB13 expression in lung adenocarcinoma cells, and patient-derived xenografts and depletion of ABCG1 enhanced the sensitivity of lung adenocarcinoma cells to cisplatin therapy. Our results suggest that determining the combined expression of HOXB13 and its target genes can predict patient outcomes.

Conclusions: A cisplatin-HOXB13-ABCG1/EZH2/Slug network may account for a novel mechanism underlying cisplatin resistance and metastasis after chemotherapy. Determining the levels of HOXB13 and its target genes from needle biopsy specimens may help predict the sensitivity of lung adenocarcinoma patients to platinum-based chemotherapy and patient outcomes.

Correlations of an Insertion/Deletion Polymorphism (rs10680577) in the RERT-lncRNA with the Susceptibility, Clinicopathological Features, and Prognosis of Lung Cancer

The aim of this study was to investigate the correlations of an Ins/Del polymorphism (rs10680577) in the RERT-lncRNA with the susceptibility, clinicopathological features, and prognosis of lung cancer. A total of 376 patients with lung cancer and 419 healthy subjects were enrolled in this study. The genotype of rs10680577 was performed using polymerase chain reaction (PCR) followed by polyacrylamide gel electrophoresis. Quantitative real-time PCR was used to measure RERT-lncRNA and EGLN2 expressions. Subjects with Del allele of rs10680577 exhibited an elevated risk of lung cancer. The expressions of RERT-lncRNA and EGLN2 in tumor tissues were higher than adjacent normal tissues, manifesting a positive correlation. Compared to patients with Ins/Ins genotype carriers, those with Ins/Del + Del/Del genotype carriers had upregulated expressions of RERT-lncRNA and EGLN2. Moreover, Ins/Del + Del/Del genotype and expressions of RERT-lncRNA and EGLN2 were associated with age, smoking habits, and TNM stage in lung cancer patients. Besides, patients with Ins/Ins genotype of rs10680577 had a longer OS than those with Ins/Del + Del/Del genotype carriers, and patients with lower expressions of RERT-lncRNA and EGLN2 presented a shorter OS than those with higher expressions. COX multivariate analysis demonstrated that Ins/Del + Del/Del genotype and higher expressions of RERT lncRNA and EGLN2 were risk factors affecting the prognosis of lung cancer. The Ins/Del polymorphism (rs10680577) in RERT-lncRNA was correlated with the risk, major clinicopathological features, and prognosis of lung cancer patients, and the patients with Ins/Del + Del/Del genotype carriers had higher expressions of RERT-lncRNA and EGLN2 than those with Ins/Ins carriers.