The Role of Alternative Splicing Factors, DDB2-Related Ageing and DNA Damage Repair in the Progression and Prognosis of Stomach Adenocarcinoma Patients

Enhancing low-dose radiotherapy efficacy with PARP inhibitors via FBL-mediated oxidative stress response in colorectal cancer

The effectiveness of radiotherapy in colorectal cancer (CRC) relies on its ability to induce cell death via the generation of reactive oxygen species (ROS). However, genes responsible for mitigating oxidative stress can impede radiotherapy's efficacy. In this study, we elucidate a significant association between the nucleolar protein Fibrillarin (FBL) and the oxidative stress response in CRC tumors. Our findings reveal elevated expression of FBL in colorectal cancer, which positively correlates with oxidative stress levels. Mechanistically, FBL demonstrates direct accumulation at DNA damage sites under the regulation of PARP1. Specifically, the N-terminal GAR domain of FBL is susceptible to PARylation by PARP1, enabling FBL to recognize PARylated proteins. The accumulation of damaged FBL plays a pivotal role in facilitating short-patched base excision repair by recruiting Ligase III and disassociating PCNA and FEN1. Moreover, tumors with heightened FBL expression exhibit reduced DNA damage levels but increased sensitivity to combined low-dose radiotherapy and olaparib treatment. This underscores the potential of leveraging PARP inhibitors to augment radiotherapy sensitivity in CRC cases characterized by elevated FBL expression, offering a promising therapeutic avenue.

DDB2 promotes melanoma cell growth by transcriptionally regulating the expression of KMT2A and predicts a poor prognosis

Identification of potential key targets of melanoma, a fatal skin malignancy, is critical to the development of new cancer therapies. Lysine methyltransferase 2A (KMT2A) promotes melanoma growth by activating the human telomerase reverse transcriptase (hTERT) signaling pathway; however, the exact mechanism remains elusive. This study aimed to reveal new molecular targets that regulate KMT2A expression and melanoma growth. Using biotin-streptavidin-agarose pull-down and proteomics, we identified Damage-specific DNA-binding protein 2 (DDB2) as a KMT2A promoter-binding protein in melanoma cells and validated its role as a regulator of KMT2A/hTERT signaling. DDB2 knockdown inhibited the expression of KMT2A and hTERT and inhibited the growth of melanoma cells in vitro. Conversely, overexpression of DDB2 activated the expression of KMT2A and promoted the growth of melanoma cells. Additionally, we demonstrated that DDB2 expression was higher in tumor tissues of patients with melanoma than in corresponding normal tissues and was positively correlated with KMT2A expression. Kaplan-Meier analysis showed a poor prognosis in patients with high levels of DDB2 and KMT2A. Overall, our data suggest that DDB2 promotes melanoma cell growth through the transcriptional regulation of KMT2A expression and predicts poor prognosis. Therefore, targeting DDB2 may regulate the effects of KMT2A on melanoma growth and progression, providing a new potential therapeutic strategy for melanoma.

Deep learning and machine learning approaches to classify stomach distant metastatic tumors using DNA methylation profiles

Distant metastasis of cancer is a significant contributor to cancer-related complications, and early identification of unidentified stomach adenocarcinoma is crucial for a positive prognosis. Changes inDNA methylation are being increasingly recognized as a crucial factor in predicting cancer progression. Within this research, we developed machine learning and deep learning models for distinguishing distant metastasis in samples of stomach adenocarcinoma based on DNA methylation profile. Employing deep neural networks (DNN), support vector machines (SVM), random forest (RF), Naive Bayes (NB) and decision tree (DT), and models for forecasting distant metastasis in stomach adenocarcinoma. The results show that the performance of DNN is better than that of other models, AUC and AUPR achieving 99.9 % and 99.5 % respectively. Additionally, a weighted random sampling technique was utilized to address the issue of imbalanced datasets, enabling the identification of crucial methylation markers associated with functionally significant genes in stomach distant metastasis tumors with greater performance.

Synthesis of 3-formyl-eudistomin U with anti-proliferation, anti-migration and apoptosis-promoting activities on melanoma cells

The discovery of new lead skeleton against melanoma are urgently needed due to its highly malignant and mortality. Herein, a new molecular entity (EU-5) derived from eudistomin U was synthesized with total yield of 46%, which displayed potent activity against malignant melanoma A375 cells (IC50 = 4.4 µM), no hemolytic toxicity and good physicochemical properties in silico. Colony formation and cell cycle arrest assays revealed that EU-5 suppressed cell proliferation by causing cell cycle arrest at G0/G1 phase. Wound healing and transwell assays suggested that EU-5 could effectively inhibit migration of A375 cells in a dose-dependent manner. Calcein-AM/PI staining, Annexin V-FITC/PI apoptosis detection, mitochondrial membrane potential (MMP), reactive oxygen species (ROS), transcriptomics, quantitative real‑time polymerase chain reaction (qRT‑PCR), spectrometric titration and molecular docking assays indicated that EU-5 could activate p53 signaling pathway and trigger mitochondria-mediated cell apoptosis. Taken together, this study provided a promising lead structure for the design of a new generation of anti-melanoma drugs.

Construction and validation of a nomogram for predicting the prognosis of patients with lymph node-positive invasive micropapillary carcinoma of the breast: based on SEER database and external validation cohort

Background

Invasive micropapillary carcinoma (IMPC) of the breast is a rare subtype of breast cancer with high incidence of aggressive clinical behavior, lymph node metastasis (LNM) and poor prognosis. In the present study, using the Surveillance, Epidemiology, and End Results (SEER) database, we analyzed the clinicopathological characteristics and prognostic factors of IMPC with LNM, and constructed a prognostic nomogram.

Methods

We retrospectively analyzed data for 487 breast IMPC patients with LNM in the SEER database from January 2010 to December 2015, and randomly divided these patients into a training cohort (70%) and an internal validation cohort (30%) for the construction and internal validation of the nomogram, respectively. In addition, 248 patients diagnosed with IMPC and LNM at the Fourth Hospital of Hebei Medical University from January 2010 to December 2019 were collected as an external validation cohort. Lasso regression, along with Cox regression, was used to screen risk factors. Further more, the discrimination, calibration, and clinical utility of the nomogram were assessed based on the consistency index (C-index), time-dependent receiver operating characteristic (ROC), calibration curve, and decision curve analysis (DCA).

Results

In summary, we identified six variables including molecular subtype of breast cancer, first malignant primary indicator, tumor grade, AJCC stage, radiotherapy and chemotherapy were independent prognostic factors in predicting the prognosis of IMPC patients with LNM (P < 0.05). Based on these factors, a nomogram was constructed for predicting 3- and 5-year overall survival (OS) of patients. The nomogram achieved a C-index of 0.789 (95%CI: 0.759-0.819) in the training cohort, 0.775 (95%CI: 0.731-0.819) in the internal validation cohort, and 0.788 (95%CI: 0.756-0.820) in the external validation cohort. According to the calculated patient risk score, the patients were divided into a high-risk group and a low-risk group, which showed a significant difference in the survival prognosis of the two groups (P<0.0001). The time-dependent ROC curves, calibration curves and DCA curves proved the superiority of the nomogram.

Conclusions

We have successfully constructed a nomogram that could predict 3- and 5-year OS of IMPC patients with LNM and may assist clinicians in decision-making and personalized treatment planning.

Targeting the p53 signaling pathway in cancers: Molecular mechanisms and clinical studies

Tumor suppressor p53 can transcriptionally activate downstream genes in response to stress, and then regulate the cell cycle, DNA repair, metabolism, angiogenesis, apoptosis, and other biological responses. p53 has seven functional domains and 12 splice isoforms, and different domains and subtypes play different roles. The activation and inactivation of p53 are finely regulated and are associated with phosphorylation/acetylation modification and ubiquitination modification, respectively. Abnormal activation of p53 is closely related to the occurrence and development of cancer. While targeted therapy of the p53 signaling pathway is still in its early stages and only a few drugs or treatments have entered clinical trials, the development of new drugs and ongoing clinical trials are expected to lead to the widespread use of p53 signaling-targeted therapy in cancer treatment in the future. TRIAP1 is a novel p53 downstream inhibitor of apoptosis. TRIAP1 is the homolog of yeast mitochondrial intermembrane protein MDM35, which can play a tumor-promoting role by blocking the mitochondria-dependent apoptosis pathway. This work provides a systematic overview of recent basic research and clinical progress in the p53 signaling pathway and proposes that TRIAP1 is an important therapeutic target downstream of p53 signaling.