N6-methyladenosine-modified long non-coding RNA KIF9-AS1 promotes stemness and sorafenib resistance in hepatocellular carcinoma by upregulating SHOX2 expression

World J Gastroenterol. 2024 Dec 28;30(48):5174-5190. doi: 10.3748/wjg.v30.i48.5174.

Abstract

Background: Hepatocellular carcinoma (HCC) is a prevalent and aggressive tumor. Sorafenib is the first-line treatment for patients with advanced HCC, but resistance to sorafenib has become a significant challenge in this therapy. Cancer stem cells play a crucial role in sorafenib resistance in HCC. Our previous study revealed that the long non-coding RNA (lncRNA) KIF9-AS1 is an oncogenic gene in HCC. However, the role of KIF9-AS1 in drug resistance and cancer stemness in HCC remains unclear. Herein, we aimed to investigate the function and mechanism of the lncRNA KIF9-AS1 in cancer stemness and drug resistance in HCC.

Aim: To describe the role of the lncRNA KIF9-AS1 in cancer stemness and drug resistance in HCC and elucidate the underlying mechanism.

Methods: Tumor tissue and adjacent non-cancerous tissue samples were collected from HCC patients. Sphere formation was quantified via a tumor sphere assay. Cell viability, proliferation, and apoptosis were evaluated via Cell Counting Kit-8, flow cytometry, and colony formation assays, respectively. The interactions between the lncRNA KIF9-AS1 and its downstream targets were confirmed via RNA immunoprecipitation and coimmunoprecipitation. The tumorigenic role of KIF9-AS1 was validated in a mouse model.

Results: Compared with that in normal controls, the expression of the lncRNA KIF9-AS1 was upregulated in HCC tissues. Knockdown of KIF9-AS1 inhibited stemness and attenuated sorafenib resistance in HCC cells. Mechanistically, N6-methyladenosine modification mediated by methyltransferase-like 3/insulin-like growth factor 2 mRNA-binding protein 1 stabilized and increased the expression of KIF9-AS1. Additionally, KIF9-AS1 increased the stability and expression of short stature homeobox 2 by promoting ubiquitin-specific peptidase 1-induced deubiquitination. Furthermore, depletion of KIF9-AS1 alleviated sorafenib resistance in a xenograft mouse model of HCC.

Conclusion: The N6-methyladenosine-modified lncRNA KIF9-AS1 promoted stemness and sorafenib resistance in HCC by upregulating short stature homeobox 2 expression.

Keywords: Hepatocellular carcinoma; Long non-coding RNA KIF9-AS1; Short stature homeobox 2; Sorafenib resistance; Stemness.

MeSH terms

  • Adenosine* / analogs & derivatives
  • Adenosine* / metabolism
  • Adenosine* / pharmacology
  • Animals
  • Antineoplastic Agents / pharmacology
  • Antineoplastic Agents / therapeutic use
  • Apoptosis / drug effects
  • Carcinoma, Hepatocellular* / drug therapy
  • Carcinoma, Hepatocellular* / genetics
  • Carcinoma, Hepatocellular* / metabolism
  • Carcinoma, Hepatocellular* / pathology
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Drug Resistance, Neoplasm* / genetics
  • Female
  • Gene Expression Regulation, Neoplastic*
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / metabolism
  • Humans
  • Liver Neoplasms* / drug therapy
  • Liver Neoplasms* / genetics
  • Liver Neoplasms* / metabolism
  • Liver Neoplasms* / pathology
  • Male
  • Methyltransferases / genetics
  • Methyltransferases / metabolism
  • Mice
  • Mice, Nude
  • Neoplastic Stem Cells* / drug effects
  • Neoplastic Stem Cells* / metabolism
  • Neoplastic Stem Cells* / pathology
  • RNA, Long Noncoding* / genetics
  • RNA, Long Noncoding* / metabolism
  • Sorafenib* / pharmacology
  • Sorafenib* / therapeutic use
  • Up-Regulation*
  • Xenograft Model Antitumor Assays

Substances

  • Sorafenib
  • RNA, Long Noncoding
  • Adenosine
  • N-methyladenosine
  • Homeodomain Proteins
  • METTL3 protein, human
  • Antineoplastic Agents
  • Methyltransferases