Inhibition of protein disulfide isomerase mitigates steroid-induced osteonecrosis of the femoral head by suppressing osteoclast activity through the reduction of cellular oxidative stress.

Osteonecrosis of the femoral head (ONFH) is a devastating and irreversible hip disease usually associated with increased oxidative stress due to the clinical application of high-dose or long-term glucocorticoids (GCs). Previous publications have demonstrated protein disulfide isomerase (PDI) plays a critical role in regulating cellular production of reactive oxygen species (ROS). We therefore ask whether interfering PDI could affect GCs-stimulated osteoclastogenesis. To test the hypothesis, we conducted bioinformatics and network analysis based on potential gene targets of steroid-induced osteonecrosis of the femoral head (SIONFH) in light of multiple databases and concomitantly verified the associated biological effect via the in vitro model of dexamethasone (DEX)-stimulated osteoclastogenesis. The results revealed 70 potential gene targets for SIONFH intervention, including the P4HB gene that encodes PDI. Further analysis based on network topology-based analysis techniques (NTA), protein-protein interaction (PPI) networks, and mouse cell atlas database identified the importance of PDI in regulating the cellular redox state of osteoclast during ONFH. Western blotting (WB) validations also indicated that PDI may be a positive regulator in the process of DEX-stimulated osteoclastogenesis. Hence, various PDI inhibitors were subjected to molecular docking with PDI and their performances were analyzed, including 3-Methyltoxoflavin (3M) which inhibits PDI expression, and ribostamycin sulfate (RS) which represses PDI chaperone activity. The binding energies of DEX, 3M, and RS to PDI were -5.3547, -4.2324, and -5.9917 kcal/mol, respectively. The Protein-Ligand Interaction Profiler (PLIP) analysis demonstrated that both hydrogen bonds and hydrophobic interactions were the key contributions to the DEX-PDI and 3M-PDI complexes, while only hydrogen bonds were identified as the predominant driving forces in the RS-PDI complex. Subsequent experiments showed that both 3M and RS reduced osteoclast differentiation and bone resorption activity by stifling the expression of osteoclastic markers. This reduction was primarily due to the PDI inhibitors boosting the antioxidant system, thereby reducing the production of intracellular ROS. In conclusion, our results supported PDI's involvement in SIONFH progression by regulating ROS in osteoclasts and highlighted PDI inhibitors may serve as potential options for SIONFH treatment.

Meta-analysis of FOLFIRINOX-based neoadjuvant therapy for locally advanced pancreatic cancer.

ABSTRACT: Currently, the combination of 5-fluorouracil, leucovorin, irinotecan, and oxaliplatin (FOLFIRINOX) is the standard therapy for metastatic pancreatic cancer. In recent years, FOLFIRINOX-based neoadjuvant therapy for locally advanced pancreatic cancer (LAPC) has been gaining an increasing amount of attention, owing to its ability to reduce disease stage and transform LAPC to borderline resectable or even resectable pancreatic cancer. Accordingly, we aimed to evaluate the efficacy of first-line FOLFIRINOX chemotherapy in patients with LAPC.We searched PubMed, Embase, and Cochrane Library from the time of establishment till January 1, 2020 and included studies focusing on LAPC patients who received FOLFIRINOX as first-line neoadjuvant treatment. The primary outcomes were: resection rate and radical (R0) resection rate while the secondary outcomes were: objective response rate, overall survival, progression-free survival, and rate of grade 3 to 4 adverse events. The meta package for R 3.6.2 was used for heterogeneity and publication bias testing.Twenty-one studies, including 653 patients with LAPC, were selected. After treatment with FOLFIRINOX, the resection rate was 26% (95% confidence interval [CI] = 20%-32%, I2 = 61%) and R0 resection rate was 88% (95% CI = 78%-95%, I2 = 62%). The response rate was 34% (95% CI = 25%-43%, I2 = 56%). The median overall survival and progression-free survival durations ranged from 10.0 to 32.7 months and 3.0 to 25.3 months, respectively. The observed grade 3 to 4 adverse events were neutropenia (20.0 per 100 patients, 95% CI = 14%-27%, I2 = 75%), febrile neutropenia (7.0 per 100 patients, 95% CI = 5%-9%, I2 = 42%), thrombocytopenia (6.0 per 100 patients, 95% CI = 5%-8%, I2 = 27%), nausea/vomiting (7.0 per 100 patients, 95% CI = 7%-12%, I2 = 76%), diarrhea (10.0 per 100 patients, 95% CI = 8%-12%, I2 = 38%), and fatigue (9.0 per 100 patients, 95% CI = 7%-11%, I2 = 43%).FOLFIRINOX-based neoadjuvant chemotherapy has the potential to improve the rates of resection, R0 resection, and median OS in LAPC. Our results require further validation in large, high-quality randomized controlled trials.