Silencing HIPPI Suppresses Tumor Progression in Non-Small-Cell Lung Cancer by Inhibiting DNA Replication

Abstract

Introduction Non-small cell lung cancer (NSCLC) is the most common form of lung cancer, accounting for approximately 80%–85% of all cases of lung cancer. Huntingtin interacting protein-1 interacting protein (HIPPI) is a transcription regulator and plays an important role in apoptotic cell death. However, the role of HIPPI in NSCLC remains unclear. Methods Immunohistochemistry (IHC) and qRT-PCR were performed for expression analysis. The roles of HIPPI were studied using cell counting kit-8 (CCK-8), colony formation, flow cytometry, wound healing, Transwell invasion assays and mouse xenograft model. Gene microarray analysis and bioinformatics analysis were used to identify differentially expressed genes after HIPPI silencing. Results HIPPI is highly expressed in NSCLC tissues relative to adjacent normal tissues. Targeting HIPPI by RNA interference inhibits NSCLC cell proliferation in vitro and tumor growth in vivo. HIPPI silencing also attenuates cell migration and invasion and enhances cisplatin sensitivity in NSCLC cells. Mechanistic investigation suggests that HIPPI can positively regulate the expression of MCM2, MCM6 and MCM8, which are key regulators of DNA replication. Furthermore, consistent with HIPPI, MCM2, MCM6 and MCM8 are also upregulated in NSCLC tissues. Conclusion Our study highlights the importance of HIPPI for tumor biology in NSCLC and suggests that HIPPI may be a potential therapeutic target for NSCLC treatment.

Molecular functions of MCM8 and MCM9 and their associated pathologies

“… 97 , 98 Non-small cell lung cancer He et al and Xie et al. 83 , 99 He et al. 83 Lymphoma Braggio et al and Sung et al.…”

Neutrophil infiltration associated genes on the prognosis and tumor immune microenvironment of lung adenocarcinoma

“…IHC staining was performed as described previously ( 34 ). Briefly, the tissue slices underwent deparaffinization, followed by antigen retrieval in 5 mM Tris-HCl for 10 mins using microwave pretreatment.…”

DNA replication: Mechanisms and therapeutic interventions for diseases

“…demonstrated that simvastatin combines with tamoxifen impaired breast cancer cell proliferation and resulted in apoptosis in vivo and in vitro. Knockout of MCM8 or MCM9 selectively increases cisplatin sensitivity in specific cancer cells such as HCT116 and HeLa cells 331,332 . However, siRNA‐mediated MCM8 silencing could not alter the cisplatin sensitivity of normal HFF2/T fibroblasts, indicating MCM8 may act as a molecular target just in cancer cells.…”

“…Knockout of MCM8 or MCM9 selectively increases cisplatin sensitivity in specific cancer cells such as HCT116 and HeLa cells. 331 , 332 However, siRNA‐mediated MCM8 silencing could not alter the cisplatin sensitivity of normal HFF2/T fibroblasts, indicating MCM8 may act as a molecular target just in cancer cells. Consistent with cisplatin, silencing MCM8 and MCM9 selectively hypersensitizes cancer cells to Olaparib, which may rely on MCM8‐9's role in resolving RS.…”