We investigated the function of ALKBH5 in the progression and prognosis of LIHC in this study. Consistent with the known risk factors for liver carcinoma, such as excessive alcohol consumption, viral hepatitis, and genetic predispositions(16, 17), our findings further confirm the complex and multifactorial nature of the etiology of LIHC. Notably, we found an association between high expression of ALKBH5 and LIHC. This adds a novel dimension to the already complex landscape of LIHC molecular mechanisms and provides fresh insights into potential molecular targets for therapy. Our analysis underscored the prevalence of ALKBH5 overexpression in numerous tumor types, including LIHC, thus augmenting its potential role as a pan-cancer molecular marker. Furthermore, ALKBH5 expression levels were consistently greater in LIHC clinical stage tissues compared to their normal counterparts, emphasizing its likely significance in LIHC pathological development. Intriguingly, we noted minimal variation in ALKBH5 expression across groups with differing clinical factors, suggesting that its upregulation might be a universal event in LIHC, independent of individual patient characteristics. Our research serves as a seminal contribution towards comprehending the molecular underpinnings of LIHC and provides robust evidence implicating ALKBH5 as a potential therapeutic target.
The findings in vitro point to ALKBH5 being a critical regulator of LIHC cellular behavior, influencing proliferation, migration, and invasion. We observed that ALKBH5 was significantly overexpressed in LIHC cell lines, especially in SNU387 cells. Knockdown of ALKBH5 resulted in decreased cell proliferation and impaired invasion and migration capabilities, further confirming the critical role of ALKBH5 in regulating the malignancy of LIHC cells. Corroborating previous studies, ALKBH5, recognized as a prominent m6A demethylase(18), has been identified as a key player in a diverse array of cancers, such as breast carcinoma, stomach carcinoma, and colorectal carcinoma(19, 20). The versatile roles of ALKBH5 in various cancer types entail the modulation of numerous biological processes encompassing proliferation, metastasis, migration, invasion, metastasis, as well as tumor growth. Interestingly, the influence of ALKBH5 appears to be context-dependent, with its expression level acting either as an oncogenic promoter or a tumor suppressor, depending on the type of carcinoma(21, 22). Further supporting its multifaceted role, recent evidence also points towards an intriguing interaction between ALKBH5 and NEAT1 in colorectal carcinoma, proposing the ALKBH5-NEAT1 axis as a potential therapeutic target(23). Taken together, our findings underscore ALKBH5 as an influential factor in the pathogenesis of LIHC. More thorough and in-depth research are needed, however, to elucidate the specific processes by which ALKBH5 promotes LIHC development and to prove its efficacy in clinical settings.
In the subsequent phase of our study, we performed a differential gene expression screen on LIHC patients, based on ALKBH5 expression levels. In the KEGG pathway analysis, the up-regulated DEGs-enriched KEGG pathways include Wnt signaling pathway, Renal cell carcinoma, and the Hippo signaling pathway. Shuai He et al. postulated that the WNT/β-catenin signaling pathway, a highly conserved and tightly controlled molecular mechanism, governs cellular differentiation, proliferation, and embryonic development(24). Notably, there is increasing evidence that abnormalities in WNT/β-catenin signaling contribute to the progression and development of liver carcinoma, which contained LIHC and cholangiocarcinoma(25, 26). In addition, when Takebumi Usui et al. studied cases of renal cell carcinoma liver metastases, they found that many patients with renal cell carcinoma after surgical resection would develop in the direction of liver carcinoma(27). The Hippo pathway was found to be a critical regulator of liver size, metabolism, development, regeneration, and homeostasis in genetic studies on murine livers conducted by Jordan H. Driskill and Duojia Pan. Abnormalities in this pathway may contribute to common liver diseases like liver carcinoma and fatty liver disease(28). Besides, the down-regulated DEGs are abundant in Tryptophan metabolism, Retinol metabolism, Pyruvate metabolism, Histidine and Glutathione metabolism. This underlines the intricate interplay between liver carcinoma and functional molecular metabolism within the human body. For instance, research by Qunhua Han et al. delineates an age-related metabolic imbalance in the liver involving glycerophospholipids, arachidonic acid, histidine, and linoleic acid(29). In summary, our exploration of the roles of various metabolic and signaling pathways provides valuable insights into the molecular landscape of LIHC, highlighting the potential for targeting these specific pathways for therapeutic intervention.
Through PFS survival, PPI, correlation, LASSO, Cox and other prognostic value analyses, we identified 6 key genes (HGFAC, SPP2, CFHR3, ADNP, ACIN1, TTI1) associated with LIHC prognosis. Following that, we used the GEPIA database to determine the connection between ALKBH5 and these genes, finally identifying TTI1 as the most significant prognostic gene. TTI1, or TELO2 Interacting Protein 1, plays a vital role in various biological processes, yet remains relatively understudied. Existing literature suggests that TTI1 is involved in multiple metabolic pathways and in the activation of mTORC1 signaling, which promotes cell growth(30, 31). For instance, TTI1 has been shown to facilitate survival in multiple myeloma via the mTORC1 pathway(32). Rao et al. revealed the role of TTI1 in binding ATM and DNA-PKcs, triggering the activation of p-53 and S-15 phosphorylation pathways to initiate cancer cell death programs(33). Furthermore, research on colorectal cancer by Peng Xu et al. indicated higher TTI1 expression in tumor tissue relative to adjacent normal tissue, demonstrating its critical role in colorectal cancer proliferation(34). Nevertheless, the influence of TTI1 on the development of liver carcinoma is still not clear.
We conducted a thorough study to investigate the function of TTI1 in LIHC, and the findings underscored the importance of both TTI1 and ALKBH5 in the development of LIHC. TTI1 was discovered to be considerably overexpressed in LIHC tumors as compared to normal tissues. Notably, ALKBH5 overexpression was seen to significantly enhance SNU387 cell proliferation, an effect inversely mirrored by TTI1 under-expression. TTI1 also emerged as an independent prognostic indicator for overall survival in LIHC patients, prompting us to construct a predictive TTI1 nomogram with high consistency between predicted and actual survival rates. The interaction between TTI1 and ALKBH5 revealed their influence on LIHC cell growth. Downregulation of TTI1 suppressed cell proliferation, migration and invasion, a result that was partially counteracted by ALKBH5 overexpression. TTI1 overexpression, on the other hand, enhanced cell proliferation, migration, and invasion but was inhibited by reduced ALKBH5 expression. Altogether, these findings underscore a potential regulatory role of ALKBH5 in LIHC progression via modulation of TTI1 expression, illuminating novel avenues for potential therapeutic strategies.
To sum up, our findings confirm the characterization of ALKBH5 and TTI1 as oncogenes in LIHC, emphasizing their potential as novel markers in LIHC. Through bioinformatics analysis and cellular experiments, we elucidated that the interaction between ALKBH5 and TTI1 significantly affects the proliferation, migration and invasion of LIHC cells, suggesting that ALKBH5 may exert a key regulatory influence on LIHC progression by regulating TTI1 expression. These findings greatly advance the current understanding of LIHC and pave the way for innovative directions for future research.