Objectives:Proteasomes,multi-subunit proteases,are key actors of cellular protein catabolism and a number of regulatory processes.The detection of subtle proteasome functioning in tumors may contribute to our understa...Objectives:Proteasomes,multi-subunit proteases,are key actors of cellular protein catabolism and a number of regulatory processes.The detection of subtle proteasome functioning in tumors may contribute to our understanding of the mechanisms of cancer development.The current study aimed to identify the role of low molecular mass protein 2(LMP2),a proteasome immune subunit,in the development of mouse colon 26(C26)adenocarcinoma.Methods:The functions of the LMP2 subunit in tumor development in Balb/c mice were studied using its irreversible inhibitor KZR-504.LMP2 activity was detected by the hydrolysis of the fluorogenic substrate Ac-Pro-Ala-Leu-AMC.Western blotting and Quantitative Reverse Transcription Polymerase Chain Reaction(qRT-PCR)were used.We applied fluorescent tests for cell proliferation and apoptosis.M2 macrophages were obtained by polarization of mouse bone marrow-derived macrophages using the corresponding cytokines.Results:KZR-504 showed high specificity only for the LMP2 subunit and had no negative effect on C26 cells in culture.However,KZR-504 suppressed the formation of tumor conglomerates(by 74%,p<0.001)after C26 cell transplantation in vivo,inhibited the expression of chitinase-<3-like protein 3(Chil3)gene(by 90%,p<0.001),a key marker of immunosuppressive M2 macrophages,in the tumor<microenvironment,and reduced the tumor weight compared to the control(by 48%,p<0.01).KZR-504 also suppressed<the expression of Chil3(by 68%,p<0.05)and arginase-1(Arg1)(by 90%,p<0.001),another marker gene,in M2<<macrophages and violated M0-M2 macrophage polarization in culture.Conclusion:We discovered earlier unknown functions of the proteasome LMP2 subunit to facilitate the formation of tumor conglomerates and maintain Chil3 and Arg1 expression in immunosuppressive M2 macrophages.Our work demonstrates that the proteasome LMP2 subunit can be a target for antitumor treatment.展开更多
Objective To assess the ability of tetrandrine （Tet） to enhance the sensitivity to irradiation and its mechanism in cell lines of human breast cancer p53-mutant MCF-7/ADR, p53-wild-type MCF-7 and human colon carcino...Objective To assess the ability of tetrandrine （Tet） to enhance the sensitivity to irradiation and its mechanism in cell lines of human breast cancer p53-mutant MCF-7/ADR, p53-wild-type MCF-7 and human colon carcinoma p53-mutant HT-29 as well as in C26 colorectal carcinoma-bearing BALB/c mice. Methods MCF-7/ADR, HT-29 and MCF-7 cells were exposed to irradiation in the absence or presence of tetrandrine. The effect of Tet on the cytotoxicity of X-irradiation in these three cells was determined and the effect of tetrandrine on cell cycle arrest induced by irradiation in its absence or presence was studied by flow cytometry. Moreover, mitotic index measurement determined mitosis of cells to enter mitosis. Western blotting was employed to detect cyclin B1 and Cdc2 proteins in extracts from irradiated or non-irradiated cells of MCF-7/ADR, HT-29 and MCF-7 treated with tetrandrine at various concentrations. Tumor growth delay assay was conducted to determine the radio-sensitization of tetrandrine in vivo. Results Clonogenic assay showed that tetrandrine markedly enhanced the lethal effect of X-rays on p53-mutant MCF-7/ADR and HT-29 cells and the sensitization enhancement ratio （SER） of tetrandrine was 1.51 and 1.63, but its SER was only 1.1 in p53-wt MCF-7 cells. Irradiated p53-mutant MCF-7/ADR and HT-29 cells were only arrested in G2/M phase while MCF-7 cells were arrested in G1 and G2/M phases. Radiation-induced G2 phase arrests were abrogated by tetrandrine in a concentration-dependent manner in MCF-7/ADR and HT-29 cells, whereas redistribution within MCF-7 cell cycle changed slightly. The proportion of cells in M phase increased from 1.3% to 14.7% in MCF-7/ADR cells, and from 1.5% to 13.2% in HT-29 cells, but 2.4% to 7.1% in MCF-7 cells. Furthermore, the levels of cyclin B 1 and Cdc2 expression decreased after X-irradiation in MCF-7/ADR and HT-29 cells, and the mitotic index was also lower. Tet could reverse the decrease and induce the irradiated cells to enter mitosis （M phase）. Endosomatic experiment showed that tetrandrine caused tumor growth delay in irradiated mice. Conclusion Tetrandrine boosts the cell killing activity of irradiation both in vitro and in vivo. Tetrandrine is a potent abrogator for G2 checkpoint control and can sensitize the cells to radiation.展开更多
We evaluated the antitumor effect of combined therapy with tegafur/uracil （UFT） plus leucovorin （LV） （UFT/LV） and protein-bound polysaccharide, PSK, in three mouse models of transplantable tumors. UFT/LV showed ...We evaluated the antitumor effect of combined therapy with tegafur/uracil （UFT） plus leucovorin （LV） （UFT/LV） and protein-bound polysaccharide, PSK, in three mouse models of transplantable tumors. UFT/LV showed antitumor effect against Meth A sarcoma, and the antitumor effect was enhanced when PSK given concomitantly. UFT/LV showed antitumor effect to Lewis lung carcinoma and PSK alone also showed antitumor effect at high dose, but a combination of UFT/LV and PSK resulted in no enhanced antitumor effect. Colon 26 carcinoma was weakly responsive to UFT/LV, and no enhancement of antitumor effect was found even PSK was used in combination. In conclusion, while the effect of PSK varies depending on tumor, combined use of UFT/LV and PSK may be expected to augment the antitumor effect.展开更多
基金funded by the Government program of basic research in Koltzov Institute of Developmental Biology of the Russian Academy of Sciences,number 0088-2024-0009the Ministry of Science and Higher Education of the Russian Federation,project number 075-15-2020-773(NPS).
文摘Objectives:Proteasomes,multi-subunit proteases,are key actors of cellular protein catabolism and a number of regulatory processes.The detection of subtle proteasome functioning in tumors may contribute to our understanding of the mechanisms of cancer development.The current study aimed to identify the role of low molecular mass protein 2(LMP2),a proteasome immune subunit,in the development of mouse colon 26(C26)adenocarcinoma.Methods:The functions of the LMP2 subunit in tumor development in Balb/c mice were studied using its irreversible inhibitor KZR-504.LMP2 activity was detected by the hydrolysis of the fluorogenic substrate Ac-Pro-Ala-Leu-AMC.Western blotting and Quantitative Reverse Transcription Polymerase Chain Reaction(qRT-PCR)were used.We applied fluorescent tests for cell proliferation and apoptosis.M2 macrophages were obtained by polarization of mouse bone marrow-derived macrophages using the corresponding cytokines.Results:KZR-504 showed high specificity only for the LMP2 subunit and had no negative effect on C26 cells in culture.However,KZR-504 suppressed the formation of tumor conglomerates(by 74%,p<0.001)after C26 cell transplantation in vivo,inhibited the expression of chitinase-<3-like protein 3(Chil3)gene(by 90%,p<0.001),a key marker of immunosuppressive M2 macrophages,in the tumor<microenvironment,and reduced the tumor weight compared to the control(by 48%,p<0.01).KZR-504 also suppressed<the expression of Chil3(by 68%,p<0.05)and arginase-1(Arg1)(by 90%,p<0.001),another marker gene,in M2<<macrophages and violated M0-M2 macrophage polarization in culture.Conclusion:We discovered earlier unknown functions of the proteasome LMP2 subunit to facilitate the formation of tumor conglomerates and maintain Chil3 and Arg1 expression in immunosuppressive M2 macrophages.Our work demonstrates that the proteasome LMP2 subunit can be a target for antitumor treatment.
基金supported by a grant from the Jiangsu Natural Science Foundation (No. BK2005203).
文摘Objective To assess the ability of tetrandrine （Tet） to enhance the sensitivity to irradiation and its mechanism in cell lines of human breast cancer p53-mutant MCF-7/ADR, p53-wild-type MCF-7 and human colon carcinoma p53-mutant HT-29 as well as in C26 colorectal carcinoma-bearing BALB/c mice. Methods MCF-7/ADR, HT-29 and MCF-7 cells were exposed to irradiation in the absence or presence of tetrandrine. The effect of Tet on the cytotoxicity of X-irradiation in these three cells was determined and the effect of tetrandrine on cell cycle arrest induced by irradiation in its absence or presence was studied by flow cytometry. Moreover, mitotic index measurement determined mitosis of cells to enter mitosis. Western blotting was employed to detect cyclin B1 and Cdc2 proteins in extracts from irradiated or non-irradiated cells of MCF-7/ADR, HT-29 and MCF-7 treated with tetrandrine at various concentrations. Tumor growth delay assay was conducted to determine the radio-sensitization of tetrandrine in vivo. Results Clonogenic assay showed that tetrandrine markedly enhanced the lethal effect of X-rays on p53-mutant MCF-7/ADR and HT-29 cells and the sensitization enhancement ratio （SER） of tetrandrine was 1.51 and 1.63, but its SER was only 1.1 in p53-wt MCF-7 cells. Irradiated p53-mutant MCF-7/ADR and HT-29 cells were only arrested in G2/M phase while MCF-7 cells were arrested in G1 and G2/M phases. Radiation-induced G2 phase arrests were abrogated by tetrandrine in a concentration-dependent manner in MCF-7/ADR and HT-29 cells, whereas redistribution within MCF-7 cell cycle changed slightly. The proportion of cells in M phase increased from 1.3% to 14.7% in MCF-7/ADR cells, and from 1.5% to 13.2% in HT-29 cells, but 2.4% to 7.1% in MCF-7 cells. Furthermore, the levels of cyclin B 1 and Cdc2 expression decreased after X-irradiation in MCF-7/ADR and HT-29 cells, and the mitotic index was also lower. Tet could reverse the decrease and induce the irradiated cells to enter mitosis （M phase）. Endosomatic experiment showed that tetrandrine caused tumor growth delay in irradiated mice. Conclusion Tetrandrine boosts the cell killing activity of irradiation both in vitro and in vivo. Tetrandrine is a potent abrogator for G2 checkpoint control and can sensitize the cells to radiation.
文摘We evaluated the antitumor effect of combined therapy with tegafur/uracil （UFT） plus leucovorin （LV） （UFT/LV） and protein-bound polysaccharide, PSK, in three mouse models of transplantable tumors. UFT/LV showed antitumor effect against Meth A sarcoma, and the antitumor effect was enhanced when PSK given concomitantly. UFT/LV showed antitumor effect to Lewis lung carcinoma and PSK alone also showed antitumor effect at high dose, but a combination of UFT/LV and PSK resulted in no enhanced antitumor effect. Colon 26 carcinoma was weakly responsive to UFT/LV, and no enhancement of antitumor effect was found even PSK was used in combination. In conclusion, while the effect of PSK varies depending on tumor, combined use of UFT/LV and PSK may be expected to augment the antitumor effect.
