[Exploring the mechanisms of ferroptosis in non-obstructive azoospermia based on bioinformatics and machine learning].

OBJECTIVE: To explor the potential mechanisms of ferroptosis involvement in non-obstructive azoospermia based on bioinformatics and machine learning methods. METHODS: To obtain disease-related datasets and ferroptosis-related genes, we utilized the GEO database and FerrDb database, respectively. Using the R software, the disease dataset was subjected to normalization, differential analysis, and GO and KEGG enrichment analysis. The differentially expressed genes from the disease dataset were then intersected with the ferroptosis-related genes to identify common genes. Core genes were selected using three machine learning algorithms, namely LASSO, SVM-RFE, and random forest. Further analysis included exploring immune infiltration correlation, predicting target drugs, and conducting molecular docking simulations. RESULTS: The differential analysis of the GSE45885 dataset yielded 1751 differentially expressed genes, while the GSE145467 dataset yielded 4358 differentially expressed genes. The intersection of these two gene sets resulted in a disease-related gene set consisting of 508 genes. Taking the intersection of the disease-related gene set and the ferroptosis-related gene set, we obtained 17 disease-related ferroptosis genes. After machine learning-based screening, three core genes were identified: GPX4, HSF1, and KLHDC3. CONCLUSION: The mechanism underlying the involvement of ferroptosis in non-obstructive azoospermia may be linked to the downregulation of GPX4, HSF1, and KLHDC3 expression. This finding provides a basis for subsequent in-depth mechanistic and therapeutic studies.

Development and multicenter validation of a nomogram for preoperative prediction of lymph node positivity in pancreatic cancer (NeoPangram).

BACKGROUND: Neoadjuvant therapy is associated with nodal downstaging and improved oncological outcomes in patients with lymph node (LN)-positive pancreatic cancer. This study aimed to develop and validate a nomogram to preoperatively predict LN-positive disease. METHODS: A total of 558 patients with resected pancreatic cancer were randomly and equally divided into development and internal validation cohorts. Multivariate logistic regression analysis was used to construct the nomogram. Model performance was evaluated by discrimination, calibration, and clinical usefulness. An independent multicenter cohort consisting of 250 patients was used for external validation. RESULTS: A four-marker signature was built consisting of carbohydrate antigen 19-9 (CA19-9), CA125, CA50, and CA242. A nomogram was constructed to predict LN metastasis using three predictors identified by multivariate analysis: risk score of the four-marker signature, computed tomography-reported LN status, and clinical tumor stage. The prediction model exhibited good discrimination ability, with C-indexes of 0.806, 0.742 and 0.763 for the development, internal validation, and external validation cohorts, respectively. The model also showed good calibration and clinical usefulness. A cut-off value (0.72) for the probability of LN metastasis was determined to separate low-risk and high-risk patients. Kaplan-Meier survival analysis revealed a good agreement of the survival curves between the nomogram-predicted status and the true LN status. CONCLUSIONS: This nomogram enables the identification of pancreatic cancer patients at high risk for LN positivity who may have more advanced disease and thus could potentially benefit from neoadjuvant therapy.

Influence of Docosahexaenoic Acid on Proliferation and Apoptosis in Human HepG2 Cell Line.

OBJECTIVE: This study aims to investigate the effect of different concentrations of docosahexaenoic acid (DHA) on proliferation and apoptosis in HepG2 cell lines, and to research the possible molecular mechanisms. METHODS: DHA concentration was 0 g/mL in the negative control group, and 15, 30, 45, 60 and 75 ug/mL, respectively, in the experimental groups. CCK-8 and flow cytometry methods were used to observe the growth inhibition and apoptosis rates of HepG2 cells cultured in vitro, which were treated with different concentrations of DHA. The level of ß-catenin and c-myc mRNA and protein were measured by real-time PCR and western blot, respectively. RESULTS: In the concentration range of 0-45 ug/mL, the action time was 24 hours. DHA could inhibit the growth of HepG2 cells, and there were significant differences between the experimental and control groups (P<0.01). The same was observed in each of the two groups in experimental groups. As drug concentration or action time increased, results revealed no statistical differences. Furthermore, flow cytometric analysis indicated that DHA could promote HepG2 cell apoptosis; and the apoptosis rate was greatly different between the experimental and control groups (P<0.01). The same was observed in each of the two groups in the experimental groups. Real-time PCR could detect low c-myc expression in HepG2 cells disposed by DHA, and c-myc expression was significantly different between the experimental and control groups (P<0.01). The same was observed in each of the two groups in the experimental groups. There was no obvious difference in ß-catenin expression between the experimental and control groups, and the experimental groups were all identical. Western blot demonstrated that DHA could decrease ß-catenin and c-myc protein expression in HepG2 cells. CONCLUSION: DHA could promote apoptosis and inhibit the proliferation of HepG2 cells. The possible mechanism was related with the down-regulated protein expression of ß-catenin and the mRNA expression of c-myc.

Influence of Photodynamic Therapy on Apoptosis and Invasion of Human Cholangiocarcinoma QBC939 Cell Line.

OBJECTIVE: To investigate the effect of photodynamic therapy (PDT) mediated by hematoporphyrin derivative (HPD) on apoptosis and invasion of cholangiocarcinoma QBC939 cell lines. METHODS: In vitro cultured cholangiocarcinoma QBC939 cell line was exposed to 2, 4, 6, 8, 10, 12, and 14 µg/ml HPD with 5, 10, and 15 J/cm2 light intensity, respectively. The optical density at 450 nm of the QBC939 cells was measured by CCK8 assay and its growth inhibition ratio was calculated. Flow cytometry and transwell migration assay were applied to detect cell apoptosis and invasion respectively. RT-PCR and immunocytochemistry analyses were used to detect expressions of vascular endothelial growth factor-C (VEGF-C), cyclooxygenase-2 (COX-2), and proliferating cell nuclear antigen (PCNA). Enzyme-linked immunosorbent assay (ELISA) was carried out to examine the secretion of VEGF-C and COX-2 in QBC939 cells. RESULTS: Exposure to HPD-PDT can significantly suppress the growth of QBC939 cells (all P<0.05). HPD-PDT can promote apoptosis of QBC939 cells at the early stage. When the concentration of HPD was 2 µg/ml and light irradiation was 5 J/cm2, HPD-PDT had no obvious inhibitory effect on QBC939 cell growth, but can obviously inhibit cell invasion, and significant difference was observed between the HPD-PDT and control groups (P<0.01). The HPD-PDT can reduce the mRNA and protein expressions of VEGF-C, COX-2, and PCNA, and decrease the secretion of VEGF-C and COX-2 in QBC939 cells. CONCLUSION: PDT could promote apoptosis and inhibit growth and invasion of cholangiocarcinoma cells QBC939 in vitro.

Correlation between cognitive function and the association fibers in patients with Alzheimer's disease using diffusion tensor imaging.

White matter (WM) changes, along with well-characterized cortical abnormalities, occur in patients with Alzheimer's disease (AD). We investigated the integrity of WM tracts within association fibers by the use of fractional anisotropy (FA), and the relationship between FA values and cognitive function in patients with AD. Neuropsychological examination and conventional MRI, as well as diffusion tensor imaging, (DTI) were conducted on 12 patients with mild to moderate AD and 18 cognitively healthy volunteers. DTI was performed to measure FA in the bilateral inferior fronto-occipital fasciculus (IFOF) and the superior longitudinal fasciculus (SLF). Mini-Mental State Examination (MMSE) scores and Montreal Cognitive Assessment (MoCA) values were used to evaluate cognitive function and the Clinical Dementia Rating (CDR) scale was used as a staging tool for dementia severity. FA measures were analyzed and correlated with neuropsychological data. No patient showed any WM tract abnormality on either T1-weighted or T2-weighted MRI. However, the FA values in the bilateral IFOF and SLF and the MoCA scores in patients with AD were significantly decreased (p<0.05) compared to the controls. Furthermore, the decreased FA values in the SLF were positively correlated with cognitive function (MMSE scores - right: r=0.672, p=0.033, left: r=0.919, p<0.01; MoCA values - right: r=0.747, p=0.013, left: r=0.679, p=0.031). Our findings confirmed that the loss of integrity of microstructural WM connectivity has a role in the cognitive decline of patients with AD. The data also suggest that the FA values of the SLF may be used as a clinical marker of cognitive function.