👤 Emily Birkin

Lung cancer is one of the most prevalent cancers in both men and women worldwide. The nucleic acid G4 structures have been implicated in the transcriptional programmes of cancer-related genes in some cancers such as lung cancer. However, the role of the dominant G4 resolvase DHX36 in the progression of lung cancer remains unknown. In this study, by bioinformatic analysis of public datasets (TCGA and GEO), we find DHX36 is an independent prognosis indicator in non-small-cell lung carcinoma (NSCLC) with subtype dependence. The stable lentiviral knockdown of the DHX36 results in accelerated migration and aggregation of the S-phase subpopulation in lung cancer cells. The reduction of DHX36 level de-sensitises the proliferation response of lung cancer cells to chemotherapeutic drugs such as paclitaxel with cell dependence. The knockdown of this helicase leads to promoted tumour growth, demonstrated by a 3D fluorescence spheroid lung cancer model, and the stimulation of cell colony formation as shown by single-cell cultivation. High throughput proteomic array indicates that DHX36 functions in lung cancer cells through regulating multiple signalling pathways including activation of protein activity, protein autophosphorylation, Fc-receptor signalling pathway, response to peptide hormone and stress-activated protein kinase signalling cascade. A causal transcriptomic analysis suggests that DHX36 is significantly associated with mRNA surveillance, RNA degradation, DNA replication and Myc targets. Therefore, we unveil that DHX36 presents clinical significance and plays a role in tumour suppression in lung cancer, and propose a potentially new concept for an anti-cancer therapy based on helicase-specific targeting. Show less

The nucleic acid guanine-quadruplex structures (G4s) are involved in many aspects of cancer progression. The DEAH-box polypeptide 36 (DHX36) has been identified as a dominant nucleic acid helicase which targets and disrupts DNA and RNA G4s in an ATP-dependent manner. However, the actual role of DHX36 in breast cancer remains unknown. In this study, we observed that the gene expression of DHX36 was positively associated with patient survival in breast cancer. The abundance of DHX36 is also linked with pathologic conditions and the stage of breast cancer. By using the xenograft mouse model, we demonstrated that the stable knockdown of DHX36 via lentivirus in breast cancer cells significantly promoted tumour growth. We also found that, after the DHX36 knockdown (KD), the invasion of triple-negative breast cancer cells was enhanced. In addition, we found a significant increase in the number of cells in the S-phase and a reduction of apoptosis with the response to cisplatin. DHX36 KD also desensitized the cytotoxic cellular response to paclitaxel and cisplatin. Transcriptomic profiling analysis by RNA sequencing indicated that DHX36 altered gene expression profile through the upstream activation of TNF, IFNγ, NFκb and TGFβ1. High throughput signalling analysis showed that one cluster of stress-associated kinase proteins including p53, ROCK1 and JNK were suppressed, while the mitotic checkpoint protein-serine kinases CDK1 and CDK2 were activated, as a consequence of the DHX36 knockdown. Our study reveals that DHX36 functions as a tumour suppressor and may be considered as a potential therapeutic target in breast cancer. Show less