Colorectal cancer (CRC) is a leading cause of cancer-related mortality worldwide. Platinum-based drugs, such as cisplatin and oxaliplatin, are frontline chemotherapy for CRC, effective in both monotherapy and combination regimens. However, the clinical efficacy of these treatments is often undermined by the development of drug resistance, a significant obstacle in cancer therapy. In recent years, epigenetic alterations have been recognized as key players in the acquisition of resistance to platinum drugs. Targeting these dysregulated epigenetic mechanisms with small molecules represents a promising therapeutic strategy. This review explores the complex relationship between epigenetic changes and platinum resistance in CRC, highlighting current epigenetic therapies and their effectiveness in countering resistance mechanisms. By elucidating the epigenetic underpinnings of platinum resistance, this review aims to contribute to ongoing efforts to improve treatment outcomes for CRC patients.
Chemoresistance is a huge clinical challenge in the treatment of advanced colorectal cancer (CRC). Non-coding RNAs (ncRNAs) and messenger RNA (mRNA) are involved in CRC chemoresistance. However, the profiles of long ncRNAs (lncRNAs), microRNAs (miRNAs), mRNAs and competing endogenous RNA (ceRNA) networks in CRC chemoresistance are still largely unknown. Here, we compared the gene expression profiles in chemosensitive (HCT8) and chemoresistant [HCT8/5-fluorouracil (5-Fu) and HCT8/cisplatin (DDP)] cell lines by whole-transcriptome sequencing. The common differentially expressed RNAs in two drug-resistant cells were selected to construct lncRNA–miRNA–mRNA networks. The ceRNA network closely related to chemoresistance was further established based on the widely accepted drug resistance-associated genes enriched in three signaling pathways involved in chemoresistance. In total 52 lncRNA–miRNA–mRNA pathways were screened out, among which EPHA2 and LINC02418 were identified as hub genes; thus, LINC02418/miR-372-3p/EPHA2 were further selected and proved to affect the 5-Fu and DDP resistance of CRC. Mechanistically, LINC02418 upregulated EPHA2 by functioning as a ‘sponge’ of miR-372-3p to modulate the chemoresistance of CRC. Collectively, our study uncovered the underlying mechanism of LINC02418/miR-372-3p/EPHA2 in 5-Fu and DDP resistance of CRC, which may provide potential therapeutic targets for improving the chemosensitivity of CRC.
Fluoroquinolones, including ciprofloxacin, levofloxacin, and moxifloxacin, are extensively employed as broad-spectrum antibacterial agents. However, their use is discouraged during pregnancy due to potential adverse events (AEs). The aim of this study is to systematically investigate the association between fluoroquinolones (specifically ciprofloxacin, levofloxacin, and moxifloxacin) and AEs related to pregnancy, as well as their potential impact on congenital disorders. A disproportionality analysis was conducted utilizing FDA Adverse Event Reporting System (FAERS) data spanning from the first quarter of 2004 to September 2023. The objective was to identify potential AEs signatures associated with fluoroquinolones through conducting reporting odds ratios (RORs) and Bayesian confidence propagation neural networks (BCPNN). Assessing the potential risk of pregnancy-associated AEs involved comparing each fluoroquinolone with all other medications. Additionally, in-depth comparative analyses were carried out between various fluoroquinolones and a reference drug (azithromycin). A total of 1159 cases were identified, involving AEs related to pregnancy and congenital disorders. Obvious disproportionate association of abortion spontaneous and other nine AEs was identified for fluoroquinolone during gestation. Upon comparison with all the other drugs, ciprofloxacin exhibited an elevated risk of spontaneous abortion, non-site specific bone disorders congenital and 10 other significant signals. Levofloxacin demonstrated an increased risk of congenital tongue disorders and three other significant signals. Moxifloxacin displayed a noteworthy signal indicating multiple congenital cardiac abnormalities. We present compelling evidence regarding pregnancy-related AEs and congenital disorders linked to fluoroquinolones. Considering perinatal and genotoxicity aspects, we explore whether levofloxacin or moxifloxacin might be preferable when fluoroquinolones are deemed necessary to balance the benefits of pregnant women and fetuses.
MYC dysregulation plays a crucial role in acute myeloid leukemia (AML), yet the mechanisms governing its stabilization remain incompletely understood. MYC protein turnover is tightly regulated by post-translational modifications (PTMs), especially phosphorylation-dependent ubiquitination. Our previous study identified phosphorylation at MYC Serine 67 (S67) is critical to sustain its oncogenic activity in T-cell acute lymphoblastic leukemia (T-ALL). Here, we demonstrate that MYC S67 phosphorylation is also present in AML and catalyzed by p21-activated kinase 4 (PAK4). PAK4 directly binds MYC via its MBII domain, phosphorylates S67 and disrupts FBXW7-dependent ubiquitination, thereby stabilizing MYC to sustain MYC-driven leukemogenic programs. PAK4 inhibition destabilizes MYC and suppresses AML proliferation; however, it fails to elicit robust apoptosis, primarily due to the compensatory upregulation of the anti-apoptotic factor MCL-1. Combining the PAK4 inhibitor KPT-9274 with the MCL-1 antagonist S63845 induces synergistic lethality in AML cells. These findings provide the mechanistic insight of MYC stabilization in AML and establish a PAK4 inhibition-based targeted strategy as a promising therapeutic approach for AML treatment.