INTRODUCTIONDevelopment of drug-resistance to chemotherapyand subsequent metastasis of tumor are primarilyresponsible for treatment failure and the death fromcancer. There have been many previous studies onthe relatio...INTRODUCTIONDevelopment of drug-resistance to chemotherapyand subsequent metastasis of tumor are primarilyresponsible for treatment failure and the death fromcancer. There have been many previous studies onthe relationship between expression of multidrugresistance (MDR) phenotype P-glycoprotein (P-gp)and the malignant properties of tumors, but theresults are often conflicting[1-8]. The difference intumor types or MDR phenotype induced by specificagents might account for this discrepancy. Taxotere(TXT), a member of the family of taxanes, hasantitumor activity through its effect of promotingthe polymerization of tubulin[9,10].展开更多
Colorectal cancer(CRC) is often diagnosed at an advanced stage when tumor cell dissemination has taken place. Chemo-and targeted therapies provide only a limited increase of overall survival for these patients. The ma...Colorectal cancer(CRC) is often diagnosed at an advanced stage when tumor cell dissemination has taken place. Chemo-and targeted therapies provide only a limited increase of overall survival for these patients. The major reason for clinical outcome finds its origin in therapy resistance. Escape mechanisms to both chemo-and targeted therapy remain the main culprits. Here, we evaluate major resistant mechanisms and elaborate on potential new therapies. Amongst promising therapies is α-amanitin antibodydrug conjugate targeting hemizygous p53 loss. It becomes clear that a dynamic interaction with the tumor microenvironment exists and that this dictates therapeutic outcome. In addition, CRC displays a limited response to checkpoint inhibitors, as only a minority of patients with microsatellite instable high tumors is susceptible. In this review, we highlight new developments with clinical potentials to augment responses to checkpoint inhibitors.展开更多
Intrinsic or acquired resistance to chemotherapy is a major hurdle in the treatment of cancer.One of the key mechanisms of resistance is the overexpression of the drug efflux transporter P-glycoprotein(Pgp).Pgp overex...Intrinsic or acquired resistance to chemotherapy is a major hurdle in the treatment of cancer.One of the key mechanisms of resistance is the overexpression of the drug efflux transporter P-glycoprotein(Pgp).Pgp overexpression renders a large number of mechanistically unrelated chemotherapies ineffective.Targeting Pgp inhibition directly to overcome drug resistance,although conceptually and mechanistically attractive,has not translated to the clinic,in part because Pgp also has a critical protective function in many healthy tissues.It was recently discovered that carbonic anhydrase XII(CA XII),an enzyme associated with pH regulation in cancer,is co-expressed and co-located with Pgp in drug resistant cancer cells.CA XII is also upregulated by hypoxia,which is another microenvironmental factor that contributes to drug resistance.Here,we review findings that demonstrate modulation of CA XII may offer a promising new approach towards overcoming the longstanding hurdle of drug resistance and therapy failure against solid cancers.This review covers the use of CA XII inhibitors,both small molecule and antibody,in combination with chemotherapeutics that are substrates for Pgp.This combination therapy approach restores the efficacy of chemotherapy in resistant cells and offers a potential new therapeutic window to re-examine the targeting of Pgp as a safe,effective,and novel anticancer strategy.展开更多
Aim:Several cationic radiotracers originally developed as myocardial perfusion agents have shown potential for both early detection of cancer and non-invasive monitoring of multiple drug resistance(MDR)by single photo...Aim:Several cationic radiotracers originally developed as myocardial perfusion agents have shown potential for both early detection of cancer and non-invasive monitoring of multiple drug resistance(MDR)by single photon emission computed tomography.We have introduced two cationic complexes,^(99m)Tc-DMEOP[di-methoxy-tris-pyrazolyl-^(99m)Tc-(CO)_(3)]and ^(99m)Tc-TMEOP[tri-methoxy-tris-pyrazolyl-^(99m)Tc-(CO)_(3)],which showed excellent preclinical results as cardiac imaging probes,namely a persistent heart uptake with rapid blood and liver clearance.This study aimed at the evaluation of their usefulness for tumoral detection and functional assessment of MDR.Methods:The uptake and efflux kinetics of ^(99m)Tc-DMEOP and ^(99m)Tc-TMEOP were evaluated in human prostate,lung,and breast cancer cell lines,including drug-resistant cell lines that are known to overexpress the MDR P-glycoprotein(Pgp).The effects of MDR modulators were also studied.In vivo studies were performed in xenografted tumor models,and the MDR phenotype of the tumors was confirmed by Western blot.Results:The uptake kinetics of both complexes in human cancer cell lines is comparable with the one found for ^(99m)Tc-Sestamibi,increasing over time.The uptake of ^(99m)Tc-TMEOP is greatly reduced in cells overexpressing Pgp and increased in the presence of a Pgp modulator.In nude mice,the tumor uptake of ^(99m)Tc-TMEOP was higher in the MCF-7 xenografts compared with the MCF7 Pgp tumors.Conclusion:The uptake kinetics of both complexes in human cancer cell lines is comparable with the one found for ^(99m)Tc-Sestamibi,increasing over time.The uptake of ^(99m)Tc-TMEOP is greatly reduced in cells overexpressing Pgp,and increased in the presence of a Pgp modulator.In nude mice,the tumor uptake of ^(99m)Tc-TMEOP was higher in the MCF-7 xenografts compared with the MCF7 Pgp tumors.展开更多
Aim:Anti-CD20 monoclonal antibody is a cornerstone therapy for follicular lymphoma.Following anti-CD20 therapy,a potential decrease in CD20 antigen,and therefore a loss of the tumor target might be expected.However,th...Aim:Anti-CD20 monoclonal antibody is a cornerstone therapy for follicular lymphoma.Following anti-CD20 therapy,a potential decrease in CD20 antigen,and therefore a loss of the tumor target might be expected.However,the incidence and clinical significance of CD20 loss on tumor cells in patients with relapsed or refractory follicular lymphoma are unknown.This study aims to investigate the incidence and outcome of patients with relapsed or refractory follicular lymphoma patients harboring the loss of the tumor target,CD20.Methods:All consecutive adult patients with relapsed or refractory follicular lymphoma referred to the Early Drug Department at Gustave Roussy were included.The main objectives were to assess the incidence and prognosis of the loss in expression of CD20 antigen on the surface of tumor cells on patient outcome.Results:Over the study period 2013-2018,131 patients were screened for clinical trials with B-cell malignancies in the early drug department of Gustave Roussy in France.Forty-four patients presented with relapsed or refractory follicular lymphoma and 32 had tumor biopsies at the time of relapse that were retained for analysis.The median(range)age was 67.5 years(55.3-75.3)and the median number of prior anti-cancer systemic therapies was 3(2-4).At the time of relapse,CD20 expression was positive in 84%of tumors(n=27)and negative in 16%of tumors(n=5).At a median follow-up of 18.3(0.6-83.3)months,CD20 negativity was associated with a poorer prognosis with a median overall survival of 8.9 months(95%CI:2.4-19.1)in comparison to CD20 positive patients(28.3 months,95%CI:25.1-75.3 months,P=0.019).Conclusion:The loss of the tumor target antigen,CD20,occurred in 16%of patients with relapse or refractory follicular lymphoma.Due to confounding factors in patients who received anti-CD20 immunotherapy,it was not possible to formally establish the prognostic significance of CD20 negativity.However,we suggest that a check for CD20 antigen positivity nevertheless be performed to adapt subsequent therapies for patients with relapsed or refractory follicular lymphoma.展开更多
基金Supported in part by phone-Poulenc Rorer Pharmaceuticals INC
文摘INTRODUCTIONDevelopment of drug-resistance to chemotherapyand subsequent metastasis of tumor are primarilyresponsible for treatment failure and the death fromcancer. There have been many previous studies onthe relationship between expression of multidrugresistance (MDR) phenotype P-glycoprotein (P-gp)and the malignant properties of tumors, but theresults are often conflicting[1-8]. The difference intumor types or MDR phenotype induced by specificagents might account for this discrepancy. Taxotere(TXT), a member of the family of taxanes, hasantitumor activity through its effect of promotingthe polymerization of tubulin[9,10].
基金Supported by the National Natural Science Foundation of China,No.81620108030
文摘Colorectal cancer(CRC) is often diagnosed at an advanced stage when tumor cell dissemination has taken place. Chemo-and targeted therapies provide only a limited increase of overall survival for these patients. The major reason for clinical outcome finds its origin in therapy resistance. Escape mechanisms to both chemo-and targeted therapy remain the main culprits. Here, we evaluate major resistant mechanisms and elaborate on potential new therapies. Amongst promising therapies is α-amanitin antibodydrug conjugate targeting hemizygous p53 loss. It becomes clear that a dynamic interaction with the tumor microenvironment exists and that this dictates therapeutic outcome. In addition, CRC displays a limited response to checkpoint inhibitors, as only a minority of patients with microsatellite instable high tumors is susceptible. In this review, we highlight new developments with clinical potentials to augment responses to checkpoint inhibitors.
文摘Intrinsic or acquired resistance to chemotherapy is a major hurdle in the treatment of cancer.One of the key mechanisms of resistance is the overexpression of the drug efflux transporter P-glycoprotein(Pgp).Pgp overexpression renders a large number of mechanistically unrelated chemotherapies ineffective.Targeting Pgp inhibition directly to overcome drug resistance,although conceptually and mechanistically attractive,has not translated to the clinic,in part because Pgp also has a critical protective function in many healthy tissues.It was recently discovered that carbonic anhydrase XII(CA XII),an enzyme associated with pH regulation in cancer,is co-expressed and co-located with Pgp in drug resistant cancer cells.CA XII is also upregulated by hypoxia,which is another microenvironmental factor that contributes to drug resistance.Here,we review findings that demonstrate modulation of CA XII may offer a promising new approach towards overcoming the longstanding hurdle of drug resistance and therapy failure against solid cancers.This review covers the use of CA XII inhibitors,both small molecule and antibody,in combination with chemotherapeutics that are substrates for Pgp.This combination therapy approach restores the efficacy of chemotherapy in resistant cells and offers a potential new therapeutic window to re-examine the targeting of Pgp as a safe,effective,and novel anticancer strategy.
基金This work was supported by Covidien(Petten,The Netherlands).
文摘Aim:Several cationic radiotracers originally developed as myocardial perfusion agents have shown potential for both early detection of cancer and non-invasive monitoring of multiple drug resistance(MDR)by single photon emission computed tomography.We have introduced two cationic complexes,^(99m)Tc-DMEOP[di-methoxy-tris-pyrazolyl-^(99m)Tc-(CO)_(3)]and ^(99m)Tc-TMEOP[tri-methoxy-tris-pyrazolyl-^(99m)Tc-(CO)_(3)],which showed excellent preclinical results as cardiac imaging probes,namely a persistent heart uptake with rapid blood and liver clearance.This study aimed at the evaluation of their usefulness for tumoral detection and functional assessment of MDR.Methods:The uptake and efflux kinetics of ^(99m)Tc-DMEOP and ^(99m)Tc-TMEOP were evaluated in human prostate,lung,and breast cancer cell lines,including drug-resistant cell lines that are known to overexpress the MDR P-glycoprotein(Pgp).The effects of MDR modulators were also studied.In vivo studies were performed in xenografted tumor models,and the MDR phenotype of the tumors was confirmed by Western blot.Results:The uptake kinetics of both complexes in human cancer cell lines is comparable with the one found for ^(99m)Tc-Sestamibi,increasing over time.The uptake of ^(99m)Tc-TMEOP is greatly reduced in cells overexpressing Pgp and increased in the presence of a Pgp modulator.In nude mice,the tumor uptake of ^(99m)Tc-TMEOP was higher in the MCF-7 xenografts compared with the MCF7 Pgp tumors.Conclusion:The uptake kinetics of both complexes in human cancer cell lines is comparable with the one found for ^(99m)Tc-Sestamibi,increasing over time.The uptake of ^(99m)Tc-TMEOP is greatly reduced in cells overexpressing Pgp,and increased in the presence of a Pgp modulator.In nude mice,the tumor uptake of ^(99m)Tc-TMEOP was higher in the MCF-7 xenografts compared with the MCF7 Pgp tumors.
文摘Aim:Anti-CD20 monoclonal antibody is a cornerstone therapy for follicular lymphoma.Following anti-CD20 therapy,a potential decrease in CD20 antigen,and therefore a loss of the tumor target might be expected.However,the incidence and clinical significance of CD20 loss on tumor cells in patients with relapsed or refractory follicular lymphoma are unknown.This study aims to investigate the incidence and outcome of patients with relapsed or refractory follicular lymphoma patients harboring the loss of the tumor target,CD20.Methods:All consecutive adult patients with relapsed or refractory follicular lymphoma referred to the Early Drug Department at Gustave Roussy were included.The main objectives were to assess the incidence and prognosis of the loss in expression of CD20 antigen on the surface of tumor cells on patient outcome.Results:Over the study period 2013-2018,131 patients were screened for clinical trials with B-cell malignancies in the early drug department of Gustave Roussy in France.Forty-four patients presented with relapsed or refractory follicular lymphoma and 32 had tumor biopsies at the time of relapse that were retained for analysis.The median(range)age was 67.5 years(55.3-75.3)and the median number of prior anti-cancer systemic therapies was 3(2-4).At the time of relapse,CD20 expression was positive in 84%of tumors(n=27)and negative in 16%of tumors(n=5).At a median follow-up of 18.3(0.6-83.3)months,CD20 negativity was associated with a poorer prognosis with a median overall survival of 8.9 months(95%CI:2.4-19.1)in comparison to CD20 positive patients(28.3 months,95%CI:25.1-75.3 months,P=0.019).Conclusion:The loss of the tumor target antigen,CD20,occurred in 16%of patients with relapse or refractory follicular lymphoma.Due to confounding factors in patients who received anti-CD20 immunotherapy,it was not possible to formally establish the prognostic significance of CD20 negativity.However,we suggest that a check for CD20 antigen positivity nevertheless be performed to adapt subsequent therapies for patients with relapsed or refractory follicular lymphoma.
