5FU/Oxaliplatin-Induced Jagged1 Cleavage Counteracts Apoptosis Induction in Colorectal Cancer: A Novel Mechanism of Intrinsic Drug Resistance

WBP1 regulates mitochondrial function and ferroptosis to modulate chemoresistance in colorectal cancer

Chemoresistance continues to pose a significant challenge in managing colorectal cancer (CRC), resulting in unfavorable outcomes for patients. Recent findings indicate that ferroptosis, an innovative type of regulated cell death, might influence chemoresistance. In this research, we explored how WW domain-binding protein 1 (WBP1) affects mitochondrial function, cell growth, ferroptosis, and chemoresistance in CRC cells. By employing both genetic and pharmacological methods, we found that WBP1 is essential for maintaining mitochondrial respiration in CRC cells. WBP1 depletion impaired mitochondrial function, leading to reduced cell proliferation and increased ferroptosis. Exogenous mitochondria from wild-type cells restored mitochondrial function, cell proliferation, and suppressed ferroptosis in WBP1-deficient cells, indicating that mitochondrial function acts downstream of WBP1. Importantly, we demonstrated that targeting WBP1 or its mediated mitochondrial function sensitized chemoresistant CRC cells to 5-fluorouracil and oxaliplatin by inducing ferroptosis. Furthermore, we analyzed transcriptome data from CRC patients, which indicated that increased WBP1 expression correlated with poor outcomes for patients receiving chemotherapy, thus highlighting the clinical significance of our observations. Collectively, our results pinpoint WBP1 as a significant modulator of mitochondrial function and ferroptosis in CRC cells and imply that targeting WBP1 may represent a viable approach to tackling chemoresistance. These insights offer a deeper understanding of the molecular pathways underlying CRC chemoresistance and may guide the development of new treatment options.

Inhibition of γ-secretase/Notch pathway as a potential therapy for reversing cancer drug resistance

The mechanism of tumor drug resistance is complex and may involve stem cell maintenance, epithelial-mesenchymal transition, the activation of survival signaling pathways, transporter protein expression, and tumor microenvironment remodeling, all of which are linked to γ-secretase/Notch signaling. Increasing evidence has shown that the activation of the γ-secretase/Notch pathway is a key driver of cancer progression and drug resistance development and that γ-secretase inhibitors (GSIs) may be the most promising agents for reversing chemotherapy resistance of tumors by targeting the γ-secretase/Notch pathway. Here, we systematically summarize the roles in supporting γ-secretase/Notch activation-associated transformation of cancer cells into cancer stem cells, promotion of the EMT process, PI3K/Akt, MEK/ERK and NF-κB activation, enhancement of ABC transporter protein expression, and TME alteration in mediating tumor drug resistance. Subsequently, we analyze the mechanism of GSIs targeting the γ-secretase/Notch pathway to reverse tumor drug resistance and propose the outstanding advantages of GSIs in treating breast cancer drug resistance over other tumors. Finally, we emphasize that the development of GSIs for reversing tumor drug resistance is promising.

Notch-3 affects chemoresistance in colorectal cancer via DNA base excision repair enzymes

Colon cancer is the second leading cause of cancer death. With over 153,000 new CRC cases predicted, it is the third most commonly diagnosed cancer. Early detection can lead to curative surgical intervention, but recurrent and late metastatic disease is frequently treated with chemotherapeutic options based on induction of DNA damage. Understanding mechanism(s) that regulate DNA damage repair within colon tumor cells is essential to developing effective therapeutic strategies. The Notch signaling pathway is known to participate in normal colon development and we have recently described a pathway by which Notch-1, Notch-3 and Smad may regulated EMT and stem-like properties in colon tumor cells, promoting tumorigenesis. Little is known about how Notch may regulate drug resistance. In this study, we used shRNA to generate colon tumor cells with loss of Notch-3 expression. These cells exhibited reduced expression of the base-excision repair proteins PARP1 and APE1, along with increased sensitivity to ara-c and cisplatin. These data point to a pathway in which Notch-3 signaling can regulate DNA repair within colon tumor cells and suggests that targeting Notch-3 may be an effective approach to rendering colon tumors sensitive to chemotherapeutic drugs.

The Critical Function of microRNAs in Developing Resistance against 5- Fluorouracil in Cancer Cells

Although there have been significant advancements in cancer treatment, resistance and recurrence in patients make it one of the leading causes of death worldwide. 5-fluorouracil (5-FU), an antimetabolite agent, is widely used in treating a broad range of human malignancies. The cytotoxic effects of 5-FU are mediated by the inhibition of thymidylate synthase (TYMS/TS), resulting in the suppression of essential biosynthetic activity, as well as the misincorporation of its metabolites into RNA and DNA. Despite its huge benefits in cancer therapy, the application of 5-FU in the clinic is restricted due to the occurrence of drug resistance. MicroRNAs (miRNAs) are small, non-coding RNAs that act as negative regulators in many gene expression processes. Research has shown that changes in miRNA play a role in cancer progression and drug resistance. This review examines the role of miRNAs in 5-FU drug resistance in cancers.