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Objective:To compare the efficacy and safety of radium-223 in the treatment of metastatic castration-resistant prostate cancer (mCRPC) patients with and without homologous recombination repair (HRR) gene mutation.Methods:The clinical data of 27 patients with mCRPC bone metastases who received radium-223 therapy from April 2021 to November 2022 in Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine were retrospectively analyzed. Among the 27 mCRPC patients, 18 patients carrying HRR gene mutations belonged to the HRD(+ ) group, and 9 patients without HRR gene mutation belonged to the HRD(-) group. The age of patients in HRD(+ ) group was 69.5 (63.8, 77.0) years old, alkaline phosphatase (ALP) was 243.0 (82.8, 301.3) U/L, prostate specific antigen (PSA) was 71.6 (7.3, 329.8) ng/ml, pain score was 3.0 (1.0, 5.0) points. Eastern Cooperative Oncology Group (ECOG) score ranged from 0 to 1 points in 7 cases, and 2 points in 11 cases. In the HRD(-) group, the median age was 72.0 (64.5, 76.5) years old, ALP was 88.0 (67.5, 260.6) U/L, PSA was 19.1 (1.1, 117.8) ng/ml, and pain score was 2.0 (0, 4.5) points. The ECOG score ranged from 0 to 1 in 4 cases, and 2 in 5 cases in the HRD(-) group. There was no significant difference in the above general data between the two groups ( P>0.05). All patients received radium-223 treatment every 4 weeks, no more than 6 times. The changes of ALP, PSA, pain score and hematological adverse reactions were compared between the two groups. Results:In the HRD(+ ) group, the median number of radium-223 treatment was 4.5 (3.0, 5.3) couses, 4 patients (22.2%) completed 6 courses, and 6 patients died of prostate cancer during follow-up. In the HRD(-) group, the median number of radium treatment was 4.0 (2.5, 6.0) couses, 3 patients (33.3%) completed 6 courses, and 1 patient died of prostate cancer during follow-up. There was no significant difference in the number of radium treatment courses between the two groups ( P=0.320). ALP in HRD(+ ) group was 101.8 (61.3, 147.0) U/L after radium-223 treatment, which was significantly lower than that before treatment ( P=0.002). ALP in HRD(-) group was 73.0 (64.0, 113.5) U/L after radium-223 treatment, and it was not significantly different from that before treatment ( P=0.327). The rate of ALP response (ALP decrease >10%) in HRD(+ ) group was significantly higher than that in HRD(-) group [83.3% (15/18) vs. 44.4% (4/9), P=0.037]. PSA was 105.9(5.2, 798.4) ng/ml in HRD (+ ) group after radium-223 treatment, and was 25.6(0.8, 1 031.0) ng/ml in HRD(-) group, and they were not significantly different from that before treatment ( P=0.145, P=0.386). There were no significant differences in the rate of PSA response (PSA decrease>10%) between HRD(+ ) group and HRD(-) group [38.9% (7/18) vs. 22.2% (2/9), P=0.386]. The median pain score of HRD(+ ) group was 3.0 (0, 4.0) points after treatment, which was significantly lower than that before treatment ( P=0.028). The pain score of HRD(-) group was 1.0(0, 3.0) points after treatment, and it was not significantly different from that before treatment ( P=0.129). There was no significant difference in pain relief rate between HRD(+ ) group and HRD(-) group [66.7% (12/18) vs. 44.4% (4/9), P=0.411]. The incidence of at least one hematological adverse event during radium-223 treatment in the HRD(+ ) group was higher than that in the HRD(-) group [77.8% (14/18) vs. 33.3% (3/9), P=0.039]. There was no significant difference in the incidence of grade 1-2 hematological adverse events between the two groups [72.2%(13/18) vs. 33.3%(3/9), P=0.097]. Only 1 patient in the HRD(+ ) group experienced grade 3 anemia during treatment which was recovered after blood transfusion. Conclusions:Compared to mCRPC patients without HRR gene mutation, patients with HRR gene mutations had better ALP response and bone pain relief after radium-223 treatment. The overall incidence of adverse events in the HRD(+ ) group is higher than that in HRD(-) group, and there was no significant difference in grade 1-2 hematological adverse events between the two goups. It is necessary to expand the sample size to further verify the conclusion.
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Objective:To investigate the effect of miR-375-3p on DNA damage repair and radioresistance of colorectal cancer cells.Methods:After overexpression of miR-375-3p in HCT116 and HT29, cell proliferation ability was detected by CCK-8 assay, clone formation ability was detected by clone formation assay, apoptosis was detected by Annexin V-FITC/PI double staining method and cell cycle distribution was detected by flow cytometry, and the formation of γ-H2AX foci were used to analyze homologous recombination (HR) repair efficiency. Bioinformatics was used to predict the downstream target genes of miR-375-3p in the HR repair pathway. A dual luciferase reporter gene assay was used to validate the regulation effect of miR-375-3p on Rad51 gene. The expression of miR-375-3p in HCT116 cells irradiated with 60Co γ-rays at 2 and 6 Gy was measured by RT-qPCR. The inhibition effect of miR-375-3p on the radiosensitivity of HCT116 cells was analyzed after irradiation with different doses of 0, 1, 2, 4 and 6 Gy. Results:Overexpression of miR-375-3p inhibited the proliferation and colony formation ability, induced G1 phase cycle arrest and cell apoptosis of colorectal cancer cells, enhanced DSBs formation, inhibited Rad51 expression, and significantly decreased HR repair efficiency ( t = 10.055, P < 0.05). Dual luciferase reporter gene assay demonstrated that miR-375-3p bound to Rad51 3′UTR region ( t = 5.013, P< 0.05). In addition, irradiation increased miR-375-3p expression, and inhibition of miR-375-3p expression reduced radiosensitivity of colorectal cancer cells ( t=6.460, 5.619, 10.150, P<0.05). Conclusions:miR-375-3p inhibited the homologous recombination repair efficiency of DSBs and enhanced the radiosensitivity of colorectal cancer cells.
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Although genome-wide association studies have identified more than eighty genetic variants associated with non-small cell lung cancer (NSCLC) risk, biological mechanisms of these variants remain largely unknown. By integrating a large-scale genotype data of 15 581 lung adenocarcinoma (AD) cases, 8350 squamous cell carcinoma (SqCC) cases, and 27 355 controls, as well as multiple transcriptome and epigenomic databases, we conducted histology-specific meta-analyses and functional annotations of both reported and novel susceptibility variants. We identified 3064 credible risk variants for NSCLC, which were overrepresented in enhancer-like and promoter-like histone modification peaks as well as DNase I hypersensitive sites. Transcription factor enrichment analysis revealed that USF1 was AD-specific while CREB1 was SqCC-specific. Functional annotation and gene-based analysis implicated 894 target genes, including 274 specifics for AD and 123 for SqCC, which were overrepresented in somatic driver genes (ER = 1.95, P = 0.005). Pathway enrichment analysis and Gene-Set Enrichment Analysis revealed that AD genes were primarily involved in immune-related pathways, while SqCC genes were homologous recombination deficiency related. Our results illustrate the molecular basis of both well-studied and new susceptibility loci of NSCLC, providing not only novel insights into the genetic heterogeneity between AD and SqCC but also a set of plausible gene targets for post-GWAS functional experiments.
Subject(s)
Humans , Adenocarcinoma of Lung/genetics , Carcinoma, Non-Small-Cell Lung/genetics , Carcinoma, Squamous Cell/genetics , Genetic Heterogeneity , Genetic Predisposition to Disease , Genome-Wide Association Study , Lung Neoplasms/genetics , Polymorphism, Single NucleotideABSTRACT
Applying poly(ADP-ribose) polymerase inhibitors (PARPi) to the treatment of cancers with homologous recombination deficiency (HRDness) has been a great advance in the field of molecular therapeutics. However, in the clinic patients lacking the specific mutations or developing reverse mutations in the process of PARPi treatment may not benefit from PARPi monotherapy. Therefore, targeting homologous recombination (HR) repair with molecularly targeted agents is becoming an attractive research focus and is raising the concept of "chemical HRDness". HR repair is an evolutionarily conserved and extensively regulated process that employs sister chromatids as the template to repair DNA double-strand breaks with high fidelity. In addition to directly targeting HR components, modulation of regulatory pathways controlling HR repair is effective in achieving the "HRDness" phenotype; this includes modulation of the cell cycle checkpoint regulatory pathway, the phosphatidylinositol 3-kinase (PI3K) signaling pathway, the chromatin remodeling pathway, etc. Targeting HR repair can not only result in "synthetic lethality" when combined with PARPi, but also sensitizes cancers to traditional radio/chemotherapy and novel immunotherapy. In this review we describe the HR repair pathway and its regulatory pathways, summarize the preclinical and clinical outcomes of targeting HR repair, discuss the remaining problems in this field and provide a prospective on its application in tumor therapy.
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Objective To analyze the impact of Helicobacter pylori standard strain (Hp P12) and its virulence factor vacuolating cytotoxin A ( VacA) on DNA damage and homologous recombination ( HR) repair in a human gastric epithelial cell line (GES-1). Methods Strains of Hp P12 and vacA gene knock-out Hp P12 ( Hp P12 ΔvacA) were respectively used to infect GES-1 cells at a multiplicity of infection of 100. GES-1 cells treated with etoposide (50μmol/L) or mitomycin (0. 5μg/ml) for 2 h were used as posi-tive control. Western blot and immunofluorescence were performed to detect the expression of DNA damage marker protein γH2AX and key HR repair proteins (Rad51, pMRE11, CtIP and pCtIP) and the recruitment of them at DNA damage sites. Human embryonic kidney HEK-293 ( DR-GFP) cells were infected with Hp P12 and Hp P12 ΔvacA strains to verify the impact of VacA on HR repair efficiency. Results The expres-sion and recruitment of γH2AX and key HR repair proteins ( Rad51, pMRE11, CtIP and pCtIP) were in-creased in Hp P12-infected cells as compared with that in uninfected and Hp P12 ΔvacA-infected cells ( all P<0. 05). To evaluate the HR repair efficiency, I-SceⅠ plasmid-transfected HEK-293 (DR-GFP) cells were infected with Hp P12 and Hp P12 ΔvacA and the results showed that green fluorescent protein ( GFP)-positive cells were decreased after infection, especially in Hp P12 ΔvacA-infected cells (both P<0. 05). Conclusions Hp P12 infection could cause DNA damage and promote HR repair in GES-1 cells, in which the virulence factor VacA played an important role.
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@# Objective: The present study was aimed to explore the role and distinctive mechanism of SPIDR, the key regulatory protein of homologous recombination pathway, in progression of small cell lung cancer (SCLC). Methods: 60 SCLC specimens and 44 normal lung tissues were collected from the patients undergoing tumor resection and bronchoscopic puncture in Shanghai Pulmonary Hospital Affiliated to Tongji University from January 2013 to January 2015. The expression of SPIDR in clinical samples and NCIH446 (SCLC cell line) and MRC-5 (normal cell line) were assayed by Real-time PCR. The role of SPIDR in SCLC was investigated in vivo and in vitro by the expression of SPIDR were artificially modified in NCI-H446. Results: Smoking was significantly associated with the occurrence of SCLC (P<0.01). The expression of SPIDR mRNAin SCLC tissues was lower than that of normal lung tissues (P <0.01), and the SPIDR transcriptional and translational levels of NCI-H446 cells were also lower than that of MRC-5.Although there is no significant changes of cell growth rate and susceptibility to cisplatin and etoposide in the NCI-H446 cells overexpressing SPIDR. However, the volume of xenograft tumors of overexpressed SPIDR group decreased by 58.99% (P<0.01) and 61.84% (P<0.01) than that of the original NCI-H446 cells and the NCI-H446 cells transfected with vector (pMSCV) and the average tumor mass decreased by 61.70% (P<0.01) and 70.25% (P<0.01) respectively. When the fetal bovine serum content in the medium was reduced to 3%, the growth rate of NCI-H446 cells overexpressing SPIDR was 22.33% (P<0.01) and 20.24% (P<0.05) lower than that of the original NCIH446 cells and control group, the similar results were obtained from the 1% serum concentration experiment as well. Conclusion: The expression of SPIDR, the key regulatory protein in the DNAdouble strand break homologous recombination repair pathway, was significantly suppressed in SCLC tissues, which markedly accelerated the growth of NCI-H446 cells in vivo and reduced the reliance of NCIH446 cells to the serum. The detailed mechanism is worthy of further investigation.