New Mechanism of Gemcitabine and Its Phosphates: DNA Polymerization Disruption via 3'-5' Exonuclease Inhibition

High-density lipoprotein-based nanoplatform reprograms tumor microenvironment and enhances chemotherapy against pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is highly aggressive, with limited success in traditional therapies due to the fibrotic, immunosuppressive, pro-metastatic tumor microenvironment (TME), which collectively impede the drug accumulation and accelerate the tumor progression. In this work, we developed a PDAC-customized nutrient-mimicking reconstituted high-density lipoprotein (rHDL) capable of efficiently co-encapsulate versatile TME regulating cannabidiol and cytotoxic gemcitabine to simultaneously reprogram TME while suppressing PDAC progression. Specifically, a small-sized, nutrient-like rHDL was constructed to realize deep PDAC parenchyma penetration and efficient intra-tumoral uptake. Next, natural herbal compound cannabidiol was screened and incorporated into rHDL to regulate TME via attenuating fibrosis, reliving immunosuppression and mitigating metastatic tendency. At last, gemcitabine, the PDAC gold standard first-line therapy was co-delivered by the PDAC-customized rHDL to overcome drug resistance and amplify its PDAC suppression. Our findings demonstrate the feasibility of an integrated multi-stage TME regulation strategy for improved PDAC therapy, and might represent a modality in promoting chemotherapy against PDAC.

Chitosan-PLGA mucoadhesive nanoparticles for gemcitabine repurposing for glioblastoma therapy

Glioblastoma (GBM) is a highly deadly brain tumor that does not respond satisfactorily to conventional treatment. The non-alkylating agent gemcitabine (GEM) has been proposed for treating GBM. It can overcome MGMT protein-mediated resistance, a major limitation of conventional therapy with the alkylating agent temozolomide (TMZ). However, GEM's high systemic toxicity and poor permeability across the blood-brain barrier (BBB) pose significant challenges for its delivery to the brain. Thus, mucoadhesive poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) coated with chitosan (CH), suitable for intranasal GEM delivery, were proposed in this work. A central composite design (CCD) was implemented for NPs optimization, and NPs with appropriate characteristics for intranasal administration were obtained. in vitro studies revealed that the NPs possess excellent mucoadhesive properties and the ability to selectively release GEM in the simulated tumor tissue environment. in vitro studies using two human GBM cell lines (U215 and T98G) revealed the NPs' ability to promote GEM's antiproliferative activity to sensitize cells to the effect of TMZ. The findings of this work demonstrate that the developed CH-GEM-NPs are suitable delivery systems for GEM, both as a single therapy and as a chemosensitizer to the GBM gold standard therapy.

Pathophysiological Implications of Protein Lactylation in Pancreatic Epithelial Tumors

Protein lactylation is a post-translational modification associated with glycolysis. Although recent evidence indicates that protein lactylation is involved in epigenetic gene regulation, its pathophysiological significance remains unclear, particularly in neoplasms. Herein, we investigated the potential involvement of protein lactylation in the molecular mechanisms underlying benign and malignant pancreatic epithelial tumors, as well as its role in the response of pancreatic cancer (PC) cells to gemcitabine. Increased lactylation was observed in the nuclei of intraductal papillary mucinous adenoma, non-invasive intraductal papillary mucinous carcinoma, and invasive carcinoma, in parallel to the upregulation of hypoxia-inducible factor-1α. This observation indicated that a hypoxia-associated increase in nuclear protein lactylation could be a biochemical hallmark in pancreatic epithelial tumors. The standard PC chemotherapy drug gemcitabine suppressed histone lactylation in vitro, suggesting that histone lactylation might be relevant to its mechanism of action. Taken together, our findings suggest that protein lactylation may be involved in the development of pancreatic epithelial tumors and could represent a potential therapeutic target for PC.

Nucleoside-based anticancer drugs: Mechanism of action and drug resistance

Nucleoside-based drugs, recognized as purine or pyrimidine analogs, have been potent therapeutic agents since their introduction in 1950, deployed widely in the treatment of diverse diseases such as cancers, myelodysplastic syndromes, multiple sclerosis, and viral infections. These antimetabolites establish complex interactions with cellular molecular constituents, primarily via activation of phosphorylation cascades leading to consequential interactions with nucleic acids. However, the therapeutic efficacy of these agents is frequently compromised by the development of drug resistance, a continually emerging challenge in their clinical application. This comprehensive review explores the mechanisms of resistance to nucleoside-based drugs, encompassing a wide spectrum of phenomena from alterations in membrane transporters and activating kinases to changes in drug elimination strategies and DNA damage repair mechanisms. The critical analysis in this review underlines complex interactions of drug and cell and also guides towards novel therapeutic strategies to counteract resistance. The development of targeted therapies, novel nucleoside analogs, and synergistic drug combinations are promising approaches to restore tumor sensitivity and improve patient outcomes.

Comparison Efficacy and Safety of Gemcitabine plus Cisplatin and 5-Fluorouracil plus Cisplatin for Metastatic Nasopharyngeal Carcinoma: A Meta-Analysis and Systematic Review

Objective

To compare the efficacy and safety of gemcitabine plus cisplatin (GP) and 5-fluorouracil plus cisplatin (PF) for metastatic nasopharyngeal carcinoma.

Methods

The clinical trials of GP and PF in the treatment of metastatic nasopharyngeal carcinoma (NPC) were searched in PubMed, EMBASE, Cochrane Library, and Web of Science. The literature search met the inclusion and exclusion criteria. The software Revman 5.4 was used for data analysis, and STATA 15.0 was used for publication bias.

Results

10 studies were included in this meta-analysis. The results showed that the GP group had a higher clinical remission rate than the PF group (RR = 1.22, 95% CI (1.03–1.44), P=0.02, P=0.02). GP and PF groups in OS, PFS, and DMFS had the same effect at 1, 2, and 3 years (OS at 1 year: RR = 1.04, 95% CI (0.95–1.15), P=0.37, P=0.37; 2 years: RR = 1.08, 95% CI (0.94 1.23), P=0.28, P=0.28; 3 years: RR = 1.07, 95% CI (0.89 1.29), P=0.46; PFS at 1 year: RR = 1.98, 95% CI (0.29 13.44), P=0.49; 2 years: RR = 3.09, 95% CI (0.10 97.55), P=0.52; 3 years: RR = 0.95, 95% CI (0.73 1.24), P=0.71; DMFS at 1 year: RR = 1.01, 95% CI (0.90–1.14), P=0.83; 3 years: RR = 1.10, 95% CI (0.85–1.41), P=0.47. The number of hematological adverse reactions occurred in GP group was higher than the PF group.

Conclusion

The GP and PF groups had similar OS, PFS, and DMFS, but the GP group had a higher clinical remission rate. Therefore, GP may be the first choice for metastatic NPC.

The Relationship of Redox With Hallmarks of Cancer: The Importance of Homeostasis and Context

Redox homeostasis is a lifelong pursuit of cancer cells. Depending on the context, reactive oxygen species (ROS) exert paradoxical effects on cancers; an appropriate concentration stimulates tumorigenesis and supports the progression of cancer cells, while an excessive concentration leads to cell death. The upregulated antioxidant system in cancer cells limits ROS to a tumor-promoting level. In cancers, redox regulation interacts with tumor initiation, proliferation, metastasis, programmed cell death, autophagy, metabolic reprogramming, the tumor microenvironment, therapies, and therapeutic resistance to facilitate cancer development. This review discusses redox control and the major hallmarks of cancer.

Intraperitoneal siRNA Nanoparticles for Augmentation of Gemcitabine Efficacy in the Treatment of Pancreatic Cancer

Pancreatic ductal adenocarcinoma is a deadly disease with limited treatment options due to late diagnosis and resistance to conventional chemotherapy. Among emerging therapeutic targets, the CXCR4 chemokine receptor and polo-like kinase 1 (PLK1) play critical roles in the progression, metastasis, and chemoresistance of pancreatic cancer. Here, we tested the hypothesis that combining CXCR4 inhibition by a polymeric CXCR4 antagonist PAMD-CHOL with PLK1 knockdown by siRNA will enhance the therapeutic effect of gemcitabine (GEM) in the orthotopic model of metastatic pancreatic cancer. We formulated nanoparticles with cholesterol-modified PAMD and siPLK1 and found strong synergism when combined with GEM treatment in vitro in both murine and human pancreatic cancer cell lines. The biodistribution of the nanoparticles in orthotopic pancreatic cancer models revealed strong accumulation in primary and metastatic tumors, with limited hepatic disposition. The cholesterol-containing nanoparticles showed not only increased tumor accumulation than the cholesterol-lacking control but also deeper penetration into the tumors. In a therapeutic study in vivo, the triple combination of PAMD-CHOL/siPLK1 and GEM showed superior anticancer activity when compared with single and dual combination controls. In conclusion, PAMD-CHOL/siPLK1 nanoparticles synergistically enhance anticancer activity of GEM in pancreatic cancer and represent a promising addition to the treatment arsenal.