Oncotarget最新文献

Emerging evidence suggests a complex interplay of environmental and genetic factors in non-small cell lung cancer (NSCLC) development. Among these factors, compromised DNA repair plays a critical but incompletely understood role in lung tumorigenesis and concurrent lung diseases, such as chronic obstructive lung disease (COPD). In this study, we investigated the interplay between cigarette smoke, DNA damage and repair, focusing on the Nucleotide Excision Repair (NER) protein Xeroderma Pigmentosum Group C (XPC). We found decreased XPC mRNA expression in most NSCLCs compared to subject-matched, non-cancerous lung. In non-cancerous bronchial epithelial cells, cigarette smoke decreased NER, increased total DNA damage and resultant apoptosis, each exacerbated by XPC deficiency. In contrast, lung cancer cells exhibit greater resilience to cigarette smoke, requiring higher doses to induce comparable DNA damage and apoptosis, and are less reliant on XPC expression for survival. Importantly, XPC protects against chromosomal instability in benign bronchial epithelial cells, but not in lung cancer cells. Our findings support a "double hit" mechanism wherein early decreased XPC expression and resultant aberrant DNA repair, when combined with cigarette smoke exposure, may lead to loss of non-malignant epithelial cells (as observed in COPD), and contributes to early NSCLC transition through altered DNA damage response.

We previously showed that proliferating cell nuclear antigen (PCNA) interacts with androgen receptor (AR) through a PIP-box (PIP-box4) at the N-terminus of AR and regulates AR activity. In this study, we further investigated PCNA/AR interaction. We identified a second PIP-box (PIP-box592) in the DNA binding domain of AR and found that dihydrotestosterone enhances the binding of full-length AR (AR-FL) but not a constitutively active variant (AR-V7) to PCNA. Treatment with R9-AR-PIP, a PIP-box4-mimicking small peptide, inhibits the PCNA/AR interaction, AR occupancy at the androgen response element (ARE) in PSA and p21 genes, and expression of AR target genes, and induces cytotoxicity in AR-positive castration-resistant prostate cancer (CRPC) cells. R9-AR-PIP also significantly inhibits transcriptional activity of AR-FL upon dihydrotestosterone stimulation and the constitutive activity of AR-V7. Moreover, R9-AR-PIP and PCNA-I1S, a small molecule PCNA inhibitor, inhibit the ARE occupancy by AR-FL and AR-Vs in CCNA2 gene that encodes cyclin A2 and cyclin A2 expression. Finally, we found that cyclin A2 is overexpressed in all CRPC cells examined, suggesting that it may contribute to the development of CRPC. These data indicate that targeting PCNA/AR interaction inhibits both AR-FL- and AR-Vs-mediated signaling and implicates it could be a novel therapeutic strategy against CRPC.

Different treatment strategies are required for the non-muscle-invasive, muscle-invasive, and metastatic stages of bladder cancer. Standard treatments include surgery, chemotherapy, and radiation; however, they have their limitations. New discoveries have shown that combining immunotherapy and radiation treatment may improve patient outcomes. Radiation therapy promotes immunogenic cell death, which leads to antigen release and immune cell activation, whereas immunotherapy enhances the immune system's ability to recognize and destroy cancer cells by targeting checkpoint pathways like PD-1/PD-L1 and CTLA-4. This review examines the synergistic mechanisms of diverse modalities, focusing on their capacity to alter the tumor microenvironment and elicit systemic anti-tumor responses, such as the abscopal effect. Key clinical trials, such as BTCRC-GU15-023 and ANZUP, have demonstrated the efficacy and safety of combining these medications. However, difficulties persist, such as overlapping toxicities, unpredictability in patient responses, and a lack of accurate patient selection markers. Large-scale randomized trials are needed in the future to fine-tune treatment procedures, minimize toxicity, and validate predictive biomarkers such as PD-L1 expression and tumor mutation burden. By addressing these hurdles, the combination of radiation treatment and immunotherapy has the potential to change the bladder cancer therapeutic landscape.

Aims: Latin America has been underrepresented in trials evaluating immunotherapy for hepatocellular carcinoma (HCC). We aimed to describe the incidence of immune-related adverse events (irAEs) and their impact on outcomes in a Latin American cohort.

Methods: A multicenter prospective study was conducted in Argentina, Brazil, Chile, and Colombia, including patients who received atezolizumab plus bevacizumab. A time-covarite proportional hazard analysis evaluated the effect of irAEs.

Results: 99 patients were included. The median treatment duration was 6 months, with a median survival of 17.0 months (95% CI: 12.6-19.8). The irAE incidence rate was 2.1 cases per 100 persons-months (cumulative incidence 18.1% (95% CI: 11.1-27.2%)). Median time to irAE was 2.3 months (range 1.4-4.8), most frequently hepatitis (n = 6), thyroiditis (n = 5), and 8/18 required steroids. Follow-up, treatment duration, and overall survival were similar regardless of the occurrence of irAEs (HR = 1.71, 95% CI: 0.76-3.86; P = 0.19). Baseline alpha-feto protein ≥400 ng/ml (HR: 2.9 (95% CI: 1.1-7.6)) was independently associated with irAE.

Conclusion: The incidence of irAEs in this cohort is lower than reported in controlled trials, withouut impact on survival outcomes. Education and early recognition are crucial to ensure that these events are identified and addressed.

Redox regulation and DNA repair coordination are essential for genomic stability. Peroxiredoxin 1 (PRDX1) is a thiol-dependent peroxidase and a chaperone that protects proteins from excessive oxidation. ATM kinase (Ataxia-Telangiectasia Mutated) and the MRN (MRE11-RAD50-NBS1) complex are DNA damage signaling and repair proteins. We previously showed that cells lacking PRDX1 are sensitive to arsenite, a toxic metal that induces DNA single- and double-strand breaks (DSBs). Herein, we showed that PRDX1 interacts with ATM. PRDX1-deleted cells have reduced ATM, MRE11, and RAD50 protein levels, but not NBS1. In control cells treated with arsenite, we observed γH2AX foci formation due to arsenite-induced DSBs, and not from PRDX1-deleted cells. Arsenite caused profound depletion of ATM in PRDX1-deleted cells, suggesting that PRDX1 protects and stabilizes ATM required to form γH2AX foci. Importantly, arsenite pretreatment of PRDX1-deleted cells caused hypersensitivity to chemotherapeutic agents that generate DSBs. Analysis of a clinical cohort of ovarian cancers treated with platinum chemotherapy revealed that tumours with high PRDX1/high ATM or high PRDX1/high MRE11 expression manifested aggressive phenotypes and poor patient survival. The data suggest that PRDX1 can predict responses to chemotherapy, and targeting PRDX1 could be a viable strategy to improve the efficacy of platinum chemotherapy.

Background: Circulating tumor DNA (ctDNA) can be used as a tool to detect minimal residual disease (MRD) which can provide important prognostic information in diffuse large B-cell lymphomas (DLBCL). Here, we present an ultra-sensitive MRD assay reliant on Phased Variant Enrichment and Detection Sequencing (PhasED-Seq), which leverages phased variants to detect ctDNA.

Methods: Blank plasma samples were used to assess assay specificity and a limiting dilution series with a DLBCL clinical-contrived sample was performed to assess assay sensitivity and precision. DLBCL plasma patient samples with MRD comparator assay results were tested with PhasED-Seq technology to assess assay accuracy.

Results: The assay's false positive rate was 0.24% and the background error rate was 1.95E-08. The limit of detection at 95% detection rate with 120 ng of input DNA was 0.7 parts in 1,000,000 and precision was >96%. Positive percent agreement for the MRD assay was 90.62% (95% CI 74.98%, 98.02%) and negative percent agreement was 77.78% (95% CI 52.73, 93.59) using a single nucleotide variant-based method as reference.

Conclusions: The PhasED-Seq-based MRD assay has strong analytical and clinical performance in B-cell malignancies. Improved ctDNA detection methods such as this may improve patient outcomes through detection of residual disease or early relapse.