Etoposide (VP-16) is used for the treatment of various cancers, including nasopharyngeal carcinoma (NPC); however, cancers develop resistance to this agent by promoting DNA repair. The DNA-PK (DNA-PKcs) catalytic subunit and poly(ADP-ribose) polymerase 1 (PARP1) mediate acquired resistance and poor survival in NPC cells exposed to DNA damaging agents. DNA repair can alter the sensitivity of NPC cells to DNA damaging agents, and these two enzymes function concomitantly in response to DNA damage in vivo. Therefore, we explored the relationship between DNA-PKcs and PARP1, which may affect NPC cell survival by regulating DNA repair after VP-16 treatment. We performed quantitative real-time polymerase chain reaction, western blotting, and enzyme-linked immunoassays and found that DNA-PKcs knockdown downregulated the PARP1 and PAR expression. Conversely, PARP1 knockdown reduced DNA-PKcs activity, indicating the mutual regulation between DNA-PKcs and PARP1 in VP-16-induced DNA repair. Moreover, a combination treatment with olaparib (a PARP1 inhibitor) and NU7441 (a DNA-PKcs inhibitor) sensitized NPC cells to VP-16 in vitro and in vivo, suggesting that the combined treatment of olaparib, NU7441, and a DNA-damaging agent may be a successful treatment regimen in patients with NPC.

The kidney is a vital organ responsible for water and sodium metabolism, while the primary function of amiloride is to promote the excretion of water and sodium. We investigated amiloride enhanced the sunitinib sensitivity in RCC. We found both sunitinib and amiloride displayed cytotoxicity and exerted the synergy effect in RCC cells in vivo and in vitro arrays. Protein expression profiles were screened via MS/TMT, revealing that FN3K was upregulated in the sunitinib group, and rescued in amiloride and the combination administration. Exogenous FN3K could promote proliferation, invasion and metastasis and decrease the sensitivity of Caki-1 cells to sunitinib, also, exogenous FN3K up-regulated VEGFR2 expression and activated AKT/mTOR signal pathway. More FN3K and VEGFR2 accumulated in R-Caki-1 cells and rescued by amiloride treatment. Co-IP and IF confirmed the interaction between FN3K and VEGFR2. In conclusion, FN3K depletion mediated VEGFR2 disruption promotes amiloride synergized the anti-RCC activity of sunitinib.

Background/Objectives: Poly (ADP-ribose) polymerase (PARP) inhibitors have shown significant efficacy in treating BRCA-mutated cancers; however, a significant proportion of patients fail to respond. Emerging evidence highlights the role of PARP in lipid metabolism, suggest-ing its modulation as a novel strategy to regulate tumor progression. Methods: In this study, lipidomics and transcriptomics analyses were conducted to elucidate the mechanisms underlying PARP inhibitor-induced ferroptosis and immune modulation in triple-negative breast cancer (TNBC). Results: We demonstrated that the PARP inhibitor Niraparib significantly reprograms lipid metabolism in TNBC cells, marked by elevated phosphatidylethanolamine (PE) and cholesterol ester (ChE) levels. This metabolic shift was mechanistically linked to upregulation of the cholesterol transporter NPC1L1 via the PARP1-RELA-NPC1L1 signaling axis, which subsequently activated the AKT pathway. Combinatorial treatment with Niraparib and either Ezetimibe (an NPC1L1 inhibitor) or AZD5363 (an AKT inhibitor) synergistically enhanced TNBC cell death by promoting ferroptosis through glutathione depletion and lipid peroxidation. Furthermore, NPC1L1 inhibition amplified PARP inhibitor-induced immune responses, increasing CD8⁺ T cell infiltration and cytotoxicity in tumors. Conclusions: In conclusion, our findings establish NPC1L1 as a critical mediator of PARP inhibitor efficacy and propose dual targeting of lipid metabolism, providing a new therapeutic approach for the combination treatment of TNBC.

Background/Objectives: Acute myeloid leukemia (AML) is an aggressive malignancy marked by high relapse rates and molecular heterogeneity, necessitating the identification of novel therapeutic targets. T-complex protein 1 (TCP1), a chaperonin implicated in protein folding, remains underexplored in AML pathogenesis. This study investigates the functional role of TCP1 in AML progression and evaluates its therapeutic potential. Methods: Using successive generations of xenografted tumor models, we systematically assessed the correlation between TCP1 expression and AML tumorigenicity. Functional consequences of TCP1 silence were evaluated through in vitro proliferation assays and in vivo tumor growth monitoring. Two distinct inhibitory strategies were employed: miR-340-5p-mediated transcriptional silencing and FTY720-induced disruption of TCP1 chaperone activity. Mechanistic insights were derived from ubiquitin–proteasome pathway analysis, cell cycle profiling, and apoptosis assays. Results: High TCP1 expression correlated strongly with enhanced AML tumorigenicity. Knockdown of TCP1 significantly inhibited AML cell growth and induced degradation of AML1-ETO and PLK1 proteins through the ubiquitin–proteasome pathway. miR-340-5p effectively silenced TCP1 expression, exhibiting an inverse correlation with TCP1 levels. FTY720 disrupted TCP1′s chaperone function, leading to cell cycle arrest, apoptosis, and reduced xenograft tumor growth in murine models. Conclusion: Our findings establish TCP1 as a promising therapeutic target for AML. Both miR-340-5p and FTY720 demonstrate potent anti-leukemic effects by suppressing TCP1 activity, highlighting their potential as novel strategies to inhibit AML proliferation and improve therapeutic outcomes.