Objectives:Our previous research demonstrated that SIC-19,an innovative inhibitor of salt-inducible kinase 2(SIK2),effectively reduces SIK2 protein levels through the ubiquitin-proteasome pathway and exhibits syntheti...Objectives:Our previous research demonstrated that SIC-19,an innovative inhibitor of salt-inducible kinase 2(SIK2),effectively reduces SIK2 protein levels through the ubiquitin-proteasome pathway and exhibits synthetic lethal effects with poly ADP-ribose polymerase(PARP)inhibitors in ovarian cancer.However,the role of SIC-19 in triplenegative breast cancer(TNBC)and pancreatic cancer(PC)remains poorly defined.This study aims to investigate whether SIC-19 combined with PARP inhibitors can induce synthetic lethal effects in TNBC and PC.Methods:Cell lines with high SIK2 expression were identified through Western blot analysis.The combination’s impact was evaluated using Cell Counting Kit-8(CCK8),clone formation,and apoptosis assays,as well as in vivo xenograft models.Results:Our findings indicated that the IC50 of SIC-19 was inversely correlated with endogenous SIK2 expression in TNBC and PC cell lines.SIC-19 modulates the homologous recombination repair pathway by suppressing levels of RAD50-pS635,thereby enhancing the sensitivity of TNBC and PC cells,as well as xenografts,to PARP inhibitors.Conclusion:These results underscore the potential of combining PARP inhibitors in combination with SIK2 inhibitors as a novel therapeutic approach to increase PARP inhibition’s effectiveness in treating TNBC and PC.This innovative combination therapy represents a promising approach for overcoming resistance mechanisms and improving the outcomes for patients with these challenging malignancies.展开更多
Background:The homologous recombination deficiency(HRD)score serves as a promising biomarker to iden-tify patients who are eligible for treatment with PARP inhibitors(PARPi).Previous studies have suggested a 3-biomark...Background:The homologous recombination deficiency(HRD)score serves as a promising biomarker to iden-tify patients who are eligible for treatment with PARP inhibitors(PARPi).Previous studies have suggested a 3-biomarker Genomic Instability Score(GIS)threshold of≥42 as a valid biomarker to predict response to PARPi in patients with ovarian cancer and breast cancer.However,the GIS threshold for prostate cancer(PCa)is still lacking.Here,we conducted an exploratory analysis to investigate an appropriate HRD score threshold and to evaluate its ability to predict response to PARPi in PCa patients.Methods:A total of 181 patients with metastatic castration-resistant PCa were included in this study.Tumor tissue specimens were collected for targeted next-generation sequencing for homologous recombination repair(HRR)genes and copy number variation(CNV)analysis.The HRD score was calculated based on over 50,000 single-nucleotide polymorphisms(SNP)distributed across the human genome,incorporating three SNP-based as-says:loss of heterozygosity,telomeric allelic imbalance,and large-scale state transition.The HRD score threshold was set at the last 5th percentile of the HRD scores in our cohort of known HRR-deficient tumors.The relation-ship between the HRD score and the efficacy in 16 patients of our cohort who received PARPi treatment were retrospectively analyzed.Results:Genomic testing was succeeded in 162 patients.In our cohort,61 patients(37.7%)had HRR mutations(HRRm).BRCA mutations occurred in 15 patients(9.3%).The median HRD score was 4(ranged from 0 to 57)in the total cohort,which is much lower than that in breast and ovarian cancers.Patients who harbored HRRm and BRCA or TP53 mutations had higher HRD scores.CNV occured more frequently in patients with HRRm.The last 5th percentile of HRD scores was 43 in the HRR-mutant cohort and consequently HRD high was defined as HRD scores≥43.In the 16 patients who received PARPi in our cohort,4 patients with a high HRD score achieved an objective response rate(ORR)of 100%while 12 patients with a low HRD score achieved an ORR of 8.3%.Progression-free survival(PFS)in HRD high patients was longer compared to HRD low patients,regardless of HRRm.Conclusions:A HRD score threshold of 43 was established and preliminarily validated to predict the efficacy of PARPi in this study.Future studies are needed to further verify this threshold.展开更多
Objective:Fluzoparib(SHR3162)is a novel,potent poly(ADP-ribose)polymerases(PARP)1,2 inhibitor that showed anti-tumor activity in xenograft models.We conducted a phaseⅠ,first-in-human,dose-escalation and expansion(D-E...Objective:Fluzoparib(SHR3162)is a novel,potent poly(ADP-ribose)polymerases(PARP)1,2 inhibitor that showed anti-tumor activity in xenograft models.We conducted a phaseⅠ,first-in-human,dose-escalation and expansion(D-Esc and D-Ex)trial in patients with advanced solid cancer.Methods:This was a 3+3 phaseⅠD-Esc trial with a 3-level D-Ex at 5 hospitals in China.Eligible patients for DEsc had advanced solid tumors refractory to standard therapies,and D-Ex enrolled patients with ovarian cancer(OC).Fluzoparib was administered orally once or twice daily(bid)at 11 dose levels from 10 to 400 mg/d.Endpoints included dose-finding,safety,pharmacokinetics,and antitumor activity.Results:Seventy-nine patients were enrolled from March,2015 to January,2018[OC(47,59.5%);breast cancer(BC)(16,20.3%);colorectal cancer(8,10.1%),other tumors(8,10.1%)];48 patients were treated in the D-Esc arm and 31 in the D-Ex arm.The maximum tolerated dose(MTD)was 150 mg bid,with a half-life of 9.14 h.Grade 3/4 adverse events included anemia(7.6%)and neutropenia(5.1%).The objective response rate(ORR)was 30%(3/10)in patients with platinum-sensitive OC and 7.7%(1/13)in patients with BC.Among patients treated with fluzoparib≥120 mg/d,median progression-free survival(m PFS)was 7.2[95%confidence interval(95%CI),1.8-9.3]months in OC,9.3(95%CI,7.2-9.3)months in platinum-sensitive OC,and 3.5(range,2.0-28.0)months in BC.In patients with germline BC susceptibility gene mutation(g BRCAMut)(11/43 OC;2/16 BC),m PFS was 8.9 months for OC(range,1.0-23.2;95%CI,1.0-16.8)and 14 and 28 months for BC(those two patients both also had somatic BRCAMut).Conclusions:The MTD of fluzoparib was 150 mg bid in advanced solid malignancies.Fluzoparib demonstrated single-agent antitumor activity in BC and OC,particularly in BRCAMut and platinum-sensitive OC.展开更多
Objective： Apoptosis is a reliable marker of chemotherapeutic efficacy. Olaparib and paclitaxel inhibit proliferation and induce apoptosis in a variety of cancers. We investigated the effects of paclitaxel combined w...Objective： Apoptosis is a reliable marker of chemotherapeutic efficacy. Olaparib and paclitaxel inhibit proliferation and induce apoptosis in a variety of cancers. We investigated the effects of paclitaxel combined with olaparib on apoptosis in breast cancer Bcap37 cells. Methods： Proliferation and apoptosis were detected by MTT assay and PI staining. Degradation of procaspase-3 and poly（ADP-ribose） polymerase （PARP） was analyzed by Western blotting. Results： Compared with paclitaxel alone, paclitaxel combined with 100 mg olaparib significantly reduced survival in Bcap37 cells at all tested treatment durations （P〈0.05）; inhibition increased with increasing olaparib dose and treatment time （P〈0.01）. Combined treatment yielded significantly higher rates of apoptosis （P〈0.05）, which also increased with time （P〈0.01）. Fluorescence micrographs showed that early and late apoptotic cells increased with treatment time. Pro-caspase-3 and PARP degradation was induced by paclitaxel and enhanced by olaparib in a dose-dependent manner. Thus, combined treatment was substantially more effective than treatment with paclitaxel alone. Conclusions： Our findings suggest that paclitaxel and olaparib inhibit breast cancer Bcap37 cell proliferation and induce apoptosis. Combined treatment further reduced cell growth and enhanced apoptosis, suggesting that this combination therapy may be a promising treaunent for breast cancer.展开更多
Pancreatic cancer is one of the most aggressive cancers with a median survival time of less than 5 months,and conventional chemotherapeutics are the main treatment strategy.Poly(ADP-ribose)polymerase(PARP)inhibitors h...Pancreatic cancer is one of the most aggressive cancers with a median survival time of less than 5 months,and conventional chemotherapeutics are the main treatment strategy.Poly(ADP-ribose)polymerase(PARP)inhibitors have been recently approved for BRCA1/2-mutant pancreatic cancer,opening a new era for targeted therapy for this disease.However,most pancreatic cancer patients carry wild-type BRCA1/2 with resistance to PARP inhibitors.Here,we reported that mammalian target of rapamycin complex 2(mTORC2)kinase is overexpressed in pancreatic cancer tissues and promotes pancreatic cancer cell growth and invasion.Moreover,we found that knockdown of the mTORC2 obligate subunit Rictor sensitized pancreatic cancer cells to the PARP inhibitor olaparib.Mechanistically,we showed that mTORC2 positively regulates homologous recombination(HR)repair by modulating BRCA1 recruitment to DNA double-strand breaks(DSBs).In addition,we confirmed that combination treatment with the mTORC2 inhibitor PP242 and the PARP inhibitor olaparib synergistically inhibited pancreatic cancer growth in vivo.Thus,this study provides a novel target and strategy for optimizing PARP inhibitor efficiency in pancreatic cancers.展开更多
Ionizing radiation is frequently used to treat solid tumors,as it causes DNA damage and kill cancer cells.However,damaged DNA is repaired involving poly-(ADP-ribose)polymerase-1(PARP-1)causing resistance to radiation ...Ionizing radiation is frequently used to treat solid tumors,as it causes DNA damage and kill cancer cells.However,damaged DNA is repaired involving poly-(ADP-ribose)polymerase-1(PARP-1)causing resistance to radiation therapy.Thus,PARP-1 represents an important target in multiple cancer types,including prostate cancer.PARP is a nuclear enzyme essential for single-strand DNA breaks repair.Inhibiting PARP-1 is lethal in a wide range of cancer cells that lack the homologous recombination repair(HR)pathway.This article provides a concise and simplified overview of the development of PARP inhibitors in the laboratory and their clinical applications.We focused on the use of PARP inhibitors in various cancers,including prostate cancer.We also discussed some of the underlying principles and challenges that may affect the clinical efficacy of PARP inhibitors.展开更多
PARP is an important protein in DNA repair pathways especially the base excision repair (BER). BER is involved in DNA repair of single strand breaks (SSBs). If BER is impaired, inhibiting poly(ADP-ribose) polymerase (...PARP is an important protein in DNA repair pathways especially the base excision repair (BER). BER is involved in DNA repair of single strand breaks (SSBs). If BER is impaired, inhibiting poly(ADP-ribose) polymerase (PARP), SSBs accumulate and become double stand breaks (DSBs). The cells with increasing number of DSBs become more dependent on other repair pathways, mainly the homologous recombination (HR) and the nonhomologous end joining. Patients with defective HR, like BRCA-deficient cell lines, are even more susceptible to impairment of the BER pathway. Inhibitors of PARP preferentially kill cancer cells in BRCA-mutation cancer cell lines over normal cells. Also, PARP inhibitors increase cytotoxicity by inhibiting repair in the presence of chemotherapies that induces SSBs. These two principles have been tested clinically. Over the last few years, excitement over this class of agents has escalated due to reported activity as single agent in BRCA1- or BRCA2-associated ovarian or breast cancers, and in combination with chemotherapy in triple negative breast cancer. This review covers the current results of clinical trials testing those two principles. It also evaluates future directions for the field of PARP inhibitor development.展开更多
PARP inhibitors(PARPi)are a kind of cancer therapy that targets poly(ADP-ribose)polymerase.PARPi is the first clinically approved drug to exert synthetic lethality by obstruct-ing the DNA single-strand break repair pr...PARP inhibitors(PARPi)are a kind of cancer therapy that targets poly(ADP-ribose)polymerase.PARPi is the first clinically approved drug to exert synthetic lethality by obstruct-ing the DNA single-strand break repair process.Despite the significant therapeutic effect in pa-tients with homologous recombination(HR)repair deficiency,innate and acquired resistance to PARPi is a main challenge in the clinic.In this review,we mainly discussed the underlying mechanisms of PARPi resistance and summarized the promising solutions to overcome PARPi resistance,aiming at extending PARPi application and improving patient outcomes.展开更多
Poly(ADP-ribose)polymerase inhibitors(PARPi)are a new class of agents with unparalleled clinical achievement for driving synthetic lethality in BRCA-deficient cancers.Recent FDA approval of PARPi has motivated clinica...Poly(ADP-ribose)polymerase inhibitors(PARPi)are a new class of agents with unparalleled clinical achievement for driving synthetic lethality in BRCA-deficient cancers.Recent FDA approval of PARPi has motivated clinical trials centered around the optimization of PARPi-associated therapies in a variety of BRCA-deficient cancers.This review highlights recent advancements in understanding the molecular mechanisms of PARP‘trapping’and synthetic lethality.Particular attention is placed on the potential extension of PARPi therapies from BRCA-deficient patients to populations with other homologous recombination-deficient backgrounds,and common characteristics of PARPi and non-homologous end-joining have been elucidated.The synergistic antitumor effect of combining PARPi with various immune checkpoint blockades has been explored to evaluate the potential of combination therapy in attaining greater therapeutic outcome.This has shed light onto the differing classifications of PARPi as well as the factors that result in altered PARPi activity.Lastly,acquired chemoresistance is a crucial issue for clinical application of PARPi.The molecularmechanisms underlying PARPi resistance and potential overcoming strategies are discussed.展开更多
Globally,cervical cancer(CxCa)ranks 4th common cancer among females and led to 569,847 incidences and 311,365 deaths in 2018.80%of CxCa cases occur due to persistent infection with a high-risk subtype of human papillo...Globally,cervical cancer(CxCa)ranks 4th common cancer among females and led to 569,847 incidences and 311,365 deaths in 2018.80%of CxCa cases occur due to persistent infection with a high-risk subtype of human papillomavirus(HPV-16 and 18).Smoking,high par-ity,and co-infection with type 2 herpes simplex or HIV are other known risk factors for CxCa.Major histological subtypes are squamous(70%)and adenocarcinoma(25%).Presently,concur-rent radiation plus cisplatin(CDDP)-based chemotherapy is the standard treatment for CxCa patients.However,CDDP resistance and toxic side effects limit its efficacy,leading to a poorer response rate and an expected overall survival ranging from 10 to 17.5 months.Reduced drug uptake,increased DNA damage repair,increased CDDP inactivation,and overexpressed Bcl-2 or caspase inhibition,are primarily accountable mechanisms for CDDP resistance and improving CDDP’s efficacy remains the major challenge.Poly(ADP-ribosyl)polymerase-1,an effective mediator of nucleotide excision repair pathway,is involved in DNA repair as well as maintaining genomic stability and is significantly expressed in malignant lymphomas,hepa-tocellular-,cervical-and colorectal carcinoma,which has been approved effective in mainte-nance therapy and may serve as an effective target to enhance CDDP sensitivity in CxCa.Here,we summarize the etiology and epidemiology of and treatment for CxCa,the mechanism responsible for chemotherapy resistance,PARP inhibitor as a possible therapy for CxCa,and other possible chemotherapeutic options for CxCa treatment.展开更多
PolyADP ribose polymerase inhibitors(PARPi)have transformed the treatment of ovarian cancer.Particularly in high-grade serous ovarian cancer(HGSOC),a disease characterized by homologous recombination deficiency(HRD),P...PolyADP ribose polymerase inhibitors(PARPi)have transformed the treatment of ovarian cancer.Particularly in high-grade serous ovarian cancer(HGSOC),a disease characterized by homologous recombination deficiency(HRD),PARPi have had a rapid and profound impact on the disease course,as well as biologic and biomarker definitions of HGSOC,thereby creating a paradigm shift in the approach to treatment.In this review,we discuss the role of PARPi in the maintenance treatment of HGSOC,its effect on platinum sensitivity,and cross-resistance between platinum and PARP inhibitors.展开更多
基金supported by the National Natural Science Foundation of China to Jinhua Zhou(Nos.82172609)Jiangsu Social Development Project(Nos.BE2022729).
文摘Objectives:Our previous research demonstrated that SIC-19,an innovative inhibitor of salt-inducible kinase 2(SIK2),effectively reduces SIK2 protein levels through the ubiquitin-proteasome pathway and exhibits synthetic lethal effects with poly ADP-ribose polymerase(PARP)inhibitors in ovarian cancer.However,the role of SIC-19 in triplenegative breast cancer(TNBC)and pancreatic cancer(PC)remains poorly defined.This study aims to investigate whether SIC-19 combined with PARP inhibitors can induce synthetic lethal effects in TNBC and PC.Methods:Cell lines with high SIK2 expression were identified through Western blot analysis.The combination’s impact was evaluated using Cell Counting Kit-8(CCK8),clone formation,and apoptosis assays,as well as in vivo xenograft models.Results:Our findings indicated that the IC50 of SIC-19 was inversely correlated with endogenous SIK2 expression in TNBC and PC cell lines.SIC-19 modulates the homologous recombination repair pathway by suppressing levels of RAD50-pS635,thereby enhancing the sensitivity of TNBC and PC cells,as well as xenografts,to PARP inhibitors.Conclusion:These results underscore the potential of combining PARP inhibitors in combination with SIK2 inhibitors as a novel therapeutic approach to increase PARP inhibition’s effectiveness in treating TNBC and PC.This innovative combination therapy represents a promising approach for overcoming resistance mechanisms and improving the outcomes for patients with these challenging malignancies.
基金supported by the National Natural Science Foundation of China(grant number:82303223)the Basic and Applied Basic Research Foundation of Guangdong Province(grant numbers:2021A1515220064,2022A1515110299)the Medical Scientific Re-search Foundation of Guangdong Province(grant number:A2022492).
文摘Background:The homologous recombination deficiency(HRD)score serves as a promising biomarker to iden-tify patients who are eligible for treatment with PARP inhibitors(PARPi).Previous studies have suggested a 3-biomarker Genomic Instability Score(GIS)threshold of≥42 as a valid biomarker to predict response to PARPi in patients with ovarian cancer and breast cancer.However,the GIS threshold for prostate cancer(PCa)is still lacking.Here,we conducted an exploratory analysis to investigate an appropriate HRD score threshold and to evaluate its ability to predict response to PARPi in PCa patients.Methods:A total of 181 patients with metastatic castration-resistant PCa were included in this study.Tumor tissue specimens were collected for targeted next-generation sequencing for homologous recombination repair(HRR)genes and copy number variation(CNV)analysis.The HRD score was calculated based on over 50,000 single-nucleotide polymorphisms(SNP)distributed across the human genome,incorporating three SNP-based as-says:loss of heterozygosity,telomeric allelic imbalance,and large-scale state transition.The HRD score threshold was set at the last 5th percentile of the HRD scores in our cohort of known HRR-deficient tumors.The relation-ship between the HRD score and the efficacy in 16 patients of our cohort who received PARPi treatment were retrospectively analyzed.Results:Genomic testing was succeeded in 162 patients.In our cohort,61 patients(37.7%)had HRR mutations(HRRm).BRCA mutations occurred in 15 patients(9.3%).The median HRD score was 4(ranged from 0 to 57)in the total cohort,which is much lower than that in breast and ovarian cancers.Patients who harbored HRRm and BRCA or TP53 mutations had higher HRD scores.CNV occured more frequently in patients with HRRm.The last 5th percentile of HRD scores was 43 in the HRR-mutant cohort and consequently HRD high was defined as HRD scores≥43.In the 16 patients who received PARPi in our cohort,4 patients with a high HRD score achieved an objective response rate(ORR)of 100%while 12 patients with a low HRD score achieved an ORR of 8.3%.Progression-free survival(PFS)in HRD high patients was longer compared to HRD low patients,regardless of HRRm.Conclusions:A HRD score threshold of 43 was established and preliminarily validated to predict the efficacy of PARPi in this study.Future studies are needed to further verify this threshold.
文摘Objective:Fluzoparib(SHR3162)is a novel,potent poly(ADP-ribose)polymerases(PARP)1,2 inhibitor that showed anti-tumor activity in xenograft models.We conducted a phaseⅠ,first-in-human,dose-escalation and expansion(D-Esc and D-Ex)trial in patients with advanced solid cancer.Methods:This was a 3+3 phaseⅠD-Esc trial with a 3-level D-Ex at 5 hospitals in China.Eligible patients for DEsc had advanced solid tumors refractory to standard therapies,and D-Ex enrolled patients with ovarian cancer(OC).Fluzoparib was administered orally once or twice daily(bid)at 11 dose levels from 10 to 400 mg/d.Endpoints included dose-finding,safety,pharmacokinetics,and antitumor activity.Results:Seventy-nine patients were enrolled from March,2015 to January,2018[OC(47,59.5%);breast cancer(BC)(16,20.3%);colorectal cancer(8,10.1%),other tumors(8,10.1%)];48 patients were treated in the D-Esc arm and 31 in the D-Ex arm.The maximum tolerated dose(MTD)was 150 mg bid,with a half-life of 9.14 h.Grade 3/4 adverse events included anemia(7.6%)and neutropenia(5.1%).The objective response rate(ORR)was 30%(3/10)in patients with platinum-sensitive OC and 7.7%(1/13)in patients with BC.Among patients treated with fluzoparib≥120 mg/d,median progression-free survival(m PFS)was 7.2[95%confidence interval(95%CI),1.8-9.3]months in OC,9.3(95%CI,7.2-9.3)months in platinum-sensitive OC,and 3.5(range,2.0-28.0)months in BC.In patients with germline BC susceptibility gene mutation(g BRCAMut)(11/43 OC;2/16 BC),m PFS was 8.9 months for OC(range,1.0-23.2;95%CI,1.0-16.8)and 14 and 28 months for BC(those two patients both also had somatic BRCAMut).Conclusions:The MTD of fluzoparib was 150 mg bid in advanced solid malignancies.Fluzoparib demonstrated single-agent antitumor activity in BC and OC,particularly in BRCAMut and platinum-sensitive OC.
文摘Objective： Apoptosis is a reliable marker of chemotherapeutic efficacy. Olaparib and paclitaxel inhibit proliferation and induce apoptosis in a variety of cancers. We investigated the effects of paclitaxel combined with olaparib on apoptosis in breast cancer Bcap37 cells. Methods： Proliferation and apoptosis were detected by MTT assay and PI staining. Degradation of procaspase-3 and poly（ADP-ribose） polymerase （PARP） was analyzed by Western blotting. Results： Compared with paclitaxel alone, paclitaxel combined with 100 mg olaparib significantly reduced survival in Bcap37 cells at all tested treatment durations （P〈0.05）; inhibition increased with increasing olaparib dose and treatment time （P〈0.01）. Combined treatment yielded significantly higher rates of apoptosis （P〈0.05）, which also increased with time （P〈0.01）. Fluorescence micrographs showed that early and late apoptotic cells increased with treatment time. Pro-caspase-3 and PARP degradation was induced by paclitaxel and enhanced by olaparib in a dose-dependent manner. Thus, combined treatment was substantially more effective than treatment with paclitaxel alone. Conclusions： Our findings suggest that paclitaxel and olaparib inhibit breast cancer Bcap37 cell proliferation and induce apoptosis. Combined treatment further reduced cell growth and enhanced apoptosis, suggesting that this combination therapy may be a promising treaunent for breast cancer.
基金This work was supported by the National Natural Science Foundation of China(81572408)the Program of Medical Innovation Team and Leading Medical Talents in Jiangsu Province(2017ZXKJQW09).
文摘Pancreatic cancer is one of the most aggressive cancers with a median survival time of less than 5 months,and conventional chemotherapeutics are the main treatment strategy.Poly(ADP-ribose)polymerase(PARP)inhibitors have been recently approved for BRCA1/2-mutant pancreatic cancer,opening a new era for targeted therapy for this disease.However,most pancreatic cancer patients carry wild-type BRCA1/2 with resistance to PARP inhibitors.Here,we reported that mammalian target of rapamycin complex 2(mTORC2)kinase is overexpressed in pancreatic cancer tissues and promotes pancreatic cancer cell growth and invasion.Moreover,we found that knockdown of the mTORC2 obligate subunit Rictor sensitized pancreatic cancer cells to the PARP inhibitor olaparib.Mechanistically,we showed that mTORC2 positively regulates homologous recombination(HR)repair by modulating BRCA1 recruitment to DNA double-strand breaks(DSBs).In addition,we confirmed that combination treatment with the mTORC2 inhibitor PP242 and the PARP inhibitor olaparib synergistically inhibited pancreatic cancer growth in vivo.Thus,this study provides a novel target and strategy for optimizing PARP inhibitor efficiency in pancreatic cancers.
文摘Ionizing radiation is frequently used to treat solid tumors,as it causes DNA damage and kill cancer cells.However,damaged DNA is repaired involving poly-(ADP-ribose)polymerase-1(PARP-1)causing resistance to radiation therapy.Thus,PARP-1 represents an important target in multiple cancer types,including prostate cancer.PARP is a nuclear enzyme essential for single-strand DNA breaks repair.Inhibiting PARP-1 is lethal in a wide range of cancer cells that lack the homologous recombination repair(HR)pathway.This article provides a concise and simplified overview of the development of PARP inhibitors in the laboratory and their clinical applications.We focused on the use of PARP inhibitors in various cancers,including prostate cancer.We also discussed some of the underlying principles and challenges that may affect the clinical efficacy of PARP inhibitors.
文摘PARP is an important protein in DNA repair pathways especially the base excision repair (BER). BER is involved in DNA repair of single strand breaks (SSBs). If BER is impaired, inhibiting poly(ADP-ribose) polymerase (PARP), SSBs accumulate and become double stand breaks (DSBs). The cells with increasing number of DSBs become more dependent on other repair pathways, mainly the homologous recombination (HR) and the nonhomologous end joining. Patients with defective HR, like BRCA-deficient cell lines, are even more susceptible to impairment of the BER pathway. Inhibitors of PARP preferentially kill cancer cells in BRCA-mutation cancer cell lines over normal cells. Also, PARP inhibitors increase cytotoxicity by inhibiting repair in the presence of chemotherapies that induces SSBs. These two principles have been tested clinically. Over the last few years, excitement over this class of agents has escalated due to reported activity as single agent in BRCA1- or BRCA2-associated ovarian or breast cancers, and in combination with chemotherapy in triple negative breast cancer. This review covers the current results of clinical trials testing those two principles. It also evaluates future directions for the field of PARP inhibitor development.
文摘PARP inhibitors(PARPi)are a kind of cancer therapy that targets poly(ADP-ribose)polymerase.PARPi is the first clinically approved drug to exert synthetic lethality by obstruct-ing the DNA single-strand break repair process.Despite the significant therapeutic effect in pa-tients with homologous recombination(HR)repair deficiency,innate and acquired resistance to PARPi is a main challenge in the clinic.In this review,we mainly discussed the underlying mechanisms of PARPi resistance and summarized the promising solutions to overcome PARPi resistance,aiming at extending PARPi application and improving patient outcomes.
基金This work was supported by the National Cancer Institute,the National Institutes of Health(Grant No.R01CA236878).
文摘Poly(ADP-ribose)polymerase inhibitors(PARPi)are a new class of agents with unparalleled clinical achievement for driving synthetic lethality in BRCA-deficient cancers.Recent FDA approval of PARPi has motivated clinical trials centered around the optimization of PARPi-associated therapies in a variety of BRCA-deficient cancers.This review highlights recent advancements in understanding the molecular mechanisms of PARP‘trapping’and synthetic lethality.Particular attention is placed on the potential extension of PARPi therapies from BRCA-deficient patients to populations with other homologous recombination-deficient backgrounds,and common characteristics of PARPi and non-homologous end-joining have been elucidated.The synergistic antitumor effect of combining PARPi with various immune checkpoint blockades has been explored to evaluate the potential of combination therapy in attaining greater therapeutic outcome.This has shed light onto the differing classifications of PARPi as well as the factors that result in altered PARPi activity.Lastly,acquired chemoresistance is a crucial issue for clinical application of PARPi.The molecularmechanisms underlying PARPi resistance and potential overcoming strategies are discussed.
文摘Globally,cervical cancer(CxCa)ranks 4th common cancer among females and led to 569,847 incidences and 311,365 deaths in 2018.80%of CxCa cases occur due to persistent infection with a high-risk subtype of human papillomavirus(HPV-16 and 18).Smoking,high par-ity,and co-infection with type 2 herpes simplex or HIV are other known risk factors for CxCa.Major histological subtypes are squamous(70%)and adenocarcinoma(25%).Presently,concur-rent radiation plus cisplatin(CDDP)-based chemotherapy is the standard treatment for CxCa patients.However,CDDP resistance and toxic side effects limit its efficacy,leading to a poorer response rate and an expected overall survival ranging from 10 to 17.5 months.Reduced drug uptake,increased DNA damage repair,increased CDDP inactivation,and overexpressed Bcl-2 or caspase inhibition,are primarily accountable mechanisms for CDDP resistance and improving CDDP’s efficacy remains the major challenge.Poly(ADP-ribosyl)polymerase-1,an effective mediator of nucleotide excision repair pathway,is involved in DNA repair as well as maintaining genomic stability and is significantly expressed in malignant lymphomas,hepa-tocellular-,cervical-and colorectal carcinoma,which has been approved effective in mainte-nance therapy and may serve as an effective target to enhance CDDP sensitivity in CxCa.Here,we summarize the etiology and epidemiology of and treatment for CxCa,the mechanism responsible for chemotherapy resistance,PARP inhibitor as a possible therapy for CxCa,and other possible chemotherapeutic options for CxCa treatment.
文摘PolyADP ribose polymerase inhibitors(PARPi)have transformed the treatment of ovarian cancer.Particularly in high-grade serous ovarian cancer(HGSOC),a disease characterized by homologous recombination deficiency(HRD),PARPi have had a rapid and profound impact on the disease course,as well as biologic and biomarker definitions of HGSOC,thereby creating a paradigm shift in the approach to treatment.In this review,we discuss the role of PARPi in the maintenance treatment of HGSOC,its effect on platinum sensitivity,and cross-resistance between platinum and PARP inhibitors.
