Synergistic antitumoral activity and induction of apoptosis by novel pan Bcl-2 proteins inhibitor apogossypolone with adriamycin in human hepatocellular carcinoma.
OBJECTIVE
To investigate the in vitro and in vivo activities and related mechanism of apogossypolone (ApoG2) alone or in combination with adriamycin (ADM) against human hepatocellular carcinoma (HCC).


METHODS
The IC50 of ApoG2 in vitro was tested by WST assay, and the synergistic effect was analyzed using the CalcuSyn method. Cell apoptosis was determined using 4',6-diamidino-2- phenylindole staining and flow cytometric analysis. Western blotting was used to determine the expression of apoptosis-related proteins. In vivo activity was evaluated in the xenograft model in nude mice, and apoptosis in tumor tissues was determined by terminal deoxynucleotidyl transferase-mediated digoxigenin-dUTP nick-end labeling (TUNEL) assay.


RESULTS
The IC50 of ApoG2 in HCC cells was 17.28-30.63 micromol/L. When ApoG2 was combined with ADM, increased cytotoxicity and apoptosis were observed in SMMC-7721 cells compared to treatment with ApoG2 alone. The Western blotting results indicated that the ApoG2 induced apoptosis in SMMC-7721 cells by downregulating anti-apoptotic proteins Bcl-2, Mcl-1, and Bcl-XL, up-regulating pro-apoptotic protein Noxa, and promoting the activities of caspases-9 and -3. The tumor growth of xenograft SMMC-7721 was inhibited in nude mice when ApoG2 was administered orally without causing damage to the normal tissues. The in vivo study also indicated an increasing anti-tumoral effect when ApoG2 at 100 or 200 mg/kg dosages were used together with ADM at 5.5 mg/kg, with relative tumor proliferation rate (T/C) values of 0.456 and 0.323, respectively. Apoptosis induced in vivo by ApoG2 alone or combined with ADM was confirmed by TUNEL assay in tumor tissues.


CONCLUSIONS
ApoG2 is a potential non-toxic target agent that induces apoptosis by upregulating Noxa, while inhibiting anti-apoptotic proteins and promoting the effect of chemotherapy agent ADM in HCC.
Mi
Jin-xia
JX
Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China.
Wang
Guang-feng
GF
Wang
Heng-bang
HB
Sun
Xiao-qing
XQ
Ni
Xin-yan
XY
Zhang
Xiong-wen
XW
Tang
Jia-ming
JM
Yang
Da-jun
DJ
D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects*; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D004317:Doxorubicin / Q000494:pharmacology / Q000627:therapeutic use; D004359:Drug Therapy, Combination; D006072:Gossypol / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D006801:Humans; D020287:In Situ Nick-End Labeling; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D051379:Mice; D008819:Mice, Nude; D015394:Molecular Structure; D009368:Neoplasm Transplantation; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D014183:Transplantation, Heterologous
D000903:Antibiotics, Antineoplastic; C498702:PMAIP1 protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; C534401:apogossypolone; D004317:Doxorubicin; D006072:Gossypol