OBJECTIVEThis paper aims to study the effects of gossypol acetic acid (GAA) on proliferation and methylation level of human MutL homologue 1 (hMLH1) gene in human tongue cancer cell line Tca8113.

METHODSThe MTT assay was used to determine the effects of the acid on the proliferation inhibition in Tca8113 cells treated with different GAA concentrations. Nested methylation-specific polymerase chain reaction (nMSP) was used to detect the change in the methylation level of hMLH1 after 48 and 72 h with 30 and 15 micro mol L(-1) GAA treatment.

RESULTSMTT assay results showed the growth and proliferation inhibition of Tca8113 cells in the experimental GAA group after 24 h to 72 h of GAA treatment. The nMSP results indicated that the average optical density of hMLH1 in the Tca8113 cells significantly changed after the GAA treatment (30 micro mol L(-1) GAA for 48 h and 15 micro mol L(-1) for 72 h) (P<0.05) compared with that of the control group.

CONCLUSIONGAA does not only inhibit Tca8113 proliferation but also has a demethylation effect on the hMLH1 gene. These phenomena may be part of an underlying tumor-suppression mechanism of GAA.

Cell Line ; Cell Line, Tumor ; Cell Proliferation ; Gossypol ; analogs & derivatives ; Humans ; Methylation ; Tongue Neoplasms

Gossypol acetic acid (GAA) has been shown to have male antifertility effects, but there are pronounced differences among animal species. In the search of endogenous effector molecules, which interfere with the functions of GAA, we have studied the in vitro effect of various amino acids on the inhibition of the purified LDH-X by GAA. Histidine, cysteine and glycine were shown to block the effect of GAA. The effects of these amino acids were concentration dependent. Histidine and glycine protection was found to be complex type in which both the Km and Vmax were decreased compared to control. Arginine, glutamic acid, phenylalanine and valine were found to be ineffective against the inhibitory action of GAA.
Amino Acids/pharmacology* ; Animal ; Enzyme Inhibitors/pharmacology* ; Goats ; Gossypol/pharmacology ; Gossypol/analogs & derivatives* ; Isoenzymes ; Lactate Dehydrogenase/antagonists & inhibitors* ; Male ; Spermatocidal Agents/pharmacology* ; Testis/enzymology

To investigate the effects of gossypol acetate on apoptosis in primary cultured cells from patients with acute lymphoblastic leukemia (ALL) and chronic lymphocytic leukemia (CLL) and its synergistic effect with dexamethasone. The apoptosis-inducing effect of gossypol acetate on primary cultured leukemia cells was analyzed by flow cytometry (FCM). The effect of gossypol acetate on survival rates of Raji cells and mononuclear cells (MNC) from normal bone marrow were evaluated by MTT assay. After co-treatment with gossypol acetate and dexamethasone, the apoptosis rate of Raji cells was detected by FCM. The results showed that gossypol acetate was able to induce apoptosis in primary cultured ALL cells at concentrations of ≥ 5 µmol/L. The effect was concentration and time dependent. Apoptosis-inducing concentration in CLL cells was higher than that in ALL cells. After exposing to 50 µmol/L gossypol acetate for 48 h, the apoptosis rate of ALL and CLL cells were (90.4 ± 6.2)% and (51.7 ± 10.3)% separately. No major growth inhibitory effect was observed in MNC from normal bone marrow when they were exposed to gossypol acetate at concentrations lower than 10 µmol/L. After exposing for 48 and 72 h, the IC(50) of gossypol acetate for MNC from normal bone marrow was 7.1 and 9.1 times as much as the IC(50) of Raji cells. Co-treatment with 10 µmol/L gossypol acetate and dexamethasone remarkably increased the apoptosis rate of Raji cells. It is concluded that the gossypol acetate has apoptosis-inducing activity in primary cultured leukemia cells from patients diagnosed as ALL and CLL in vitro. The inhibitory effect of gossypol acetate on MNC from normal bone marrow is less prominent than that on Raji cells. Co-treatment with gossypol acetate and dexamethasone notably amplified the pro-apoptosis activity of the latter in Raji cells.
Apoptosis ; drug effects ; Cell Line ; Dexamethasone ; pharmacology ; Gossypol ; analogs & derivatives ; pharmacology ; Humans ; Leukemia, Lymphocytic, Chronic, B-Cell ; pathology ; Precursor Cell Lymphoblastic Leukemia-Lymphoma ; pathology ; Tumor Cells, Cultured

BACKGROUNDOur previous studies suggested that low-dose gossypol combined with steroid hormones has a reversible antifertility role in adult male rats, and the course of treatment was shorter than that of either gossypol or steroid hormones alone. This result suggested that low-dose gossypol and steroid hormones have a drug synergistic effect on antifertility. The aim of the study was to find the target organs of the antifertility synergistic effect of the combined regimen.

METHODSThirty-two adult male rats were divided into four groups randomly: group GH, rats were fed orally with gossypol acetic acid (GA, 12.5 mg×kg(-1)×d(-1)) and desogestrel (DSG, 0.125 mg×kg(-1)×d(-1))/ethinylestradiol (EE, 0.025 mg×kg(-1)×d(-1))/testosterone undecanoate (TU, 100 mg×kg(-1)×d(-1)); group G, a single dose of GA (12.5 mg×kg(-1)×d(-1)) was given; group H, the same dosage of DSG/EE/TU as in group GH were administered; group C, rats were treated with vehicle (1% methyl cellulose) as control. Testes and epididymis were removed at 8 weeks post-treatment for evaluating their weight, volumes, volume fraction, and total volume of testicular tissue structures and the seminiferous tubule diameter using stereological assay. Sperm cell numbers and the motility of epididymal sperm were quantitated by flow cytometry and morphological methods.

RESULTSCompared with group C, spermatogenesis was normal in group G and suppressed in groups H and GH. Similar changes of testicular tissue structures and sperm number were found in groups H and GH. The decreases of epididymal sperm number and motility in group GH were greater than that of the low-dose gossypol or steroid hormones alone group.

CONCLUSIONSThe suppression of spermatogenesis was induced by steroid hormones in the combined regimen, and the epididymis was the target organ of low-dose gossypol. Combined use of low-dose gossypol and steroid hormones played a comprehensive antifertility role in their synergistic effect on reducing the number and motility of epididymal sperm.

Animals ; Desogestrel ; pharmacology ; Epididymis ; drug effects ; Ethinyl Estradiol ; pharmacology ; Flow Cytometry ; Gossypol ; analogs & derivatives ; pharmacology ; Male ; Random Allocation ; Rats ; Sperm Motility ; drug effects ; Spermatogenesis ; drug effects ; Spermatozoa ; drug effects ; Testis ; drug effects ; Testosterone ; analogs & derivatives ; pharmacology

To investigate the effects of gossypol acetic acid (GA) on proliferation and apoptosis of the macrophage cell line RAW264.7 and further understand the possible underlying mechanism responsible for GA-induced cell apoptosis, RAW264.7 cells were treated with GA (25~35 micromol/L) for 24 h and the cytotoxicity was determined by MTT assay, while apoptotic cells were identified by TUNEL assay, acridine orange/ethidium bromide staining and flow cytometry. Moreover, mitochondrial membrane potential (DeltaPsi(m)) with Rhodamine 123 and reactive oxygen species (ROS) with DCFH-DA were analyzed by fluorescence spectrofluorometry. In addition, the expression of caspase-3 and caspase-9 was assessed by Western Blot assay. Finally, the GA-induced cell apoptosis was evaluated by flow cytometry in the present of caspase inhibitors Z-VAD-FMK and Ac-LEHD-FMK, respectively. GA significantly inhibited the proliferation of RAW264.7 cells in a dose-dependent manner, and caused obvious cell apoptosis and a loss of DeltaPsi(m) in RAW264.7 cells. Moreover, the ROS production in cells was elevated, and the levels of activated caspase-3 and caspase-9 were up-regulated in a dose-dependent manner. Notably, GA-induced cell apoptosis was markedly inhibited by caspase inhibitors. These results suggest that GA-induced RAW264.7 cell apoptosis may be mediated via a caspase-dependent mitochondrial signaling pathway.
Animals ; Antineoplastic Agents, Phytogenic/*pharmacology ; Apoptosis/*drug effects ; Cell Line ; Cell Proliferation/*drug effects ; Dose-Response Relationship, Drug ; Gossypol/*analogs & derivatives/pharmacology ; Membrane Potential, Mitochondrial/*drug effects ; Mice ; Mice, Inbred BALB C ; Reactive Oxygen Species/*metabolism ; Signal Transduction/*drug effects

The present study was conducted to investigate the effects of gossypol acetic acid (GAA) on the proliferation of human mucoepidermoid carcinoma cell line MEC-1 in vitro and its possible molecular mechanisms of DNA double-strand breaks (DSB). MTT assay was performed to test the inhibition of proliferation of MEC-1 cells by GAA. DSB and γH2AX foci formation induced by GAA were detected by neutral comet assay and immunostaining. GAA (5-40 μmol/L) inhibited the growth of MEC-1 cells in a dose- and time-dependent manner. One of the indexes of comet assay, percentage of head DNA was decreased, however other indexes, including tail length, percentage of tail DNA, tail moment (TM) and Olive tail moment (OTM) were increased when treated with 2.5- 40 μmol/L GAA for 24 h or 20 μmol/L GAA for 3-48 h, compared with those in control. The percentage of γH2AX-positive cells was also increased when MEC-1 was treated with 2.5-20 μmol/L GAA for 24 h or 20 μmol/L GAA for 3-48 h, compared with that in control. All these results show that GAA inhibits the proliferation of MEC-1, and DSB maybe one of the mechanisms of inhibitory effect of GAA on the growth of tumor cells.
Antineoplastic Agents, Phytogenic ; pharmacology ; Carcinoma, Mucoepidermoid ; genetics ; pathology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; DNA Breaks, Double-Stranded ; drug effects ; Gossypol ; analogs & derivatives ; pharmacology ; Humans ; Parotid Neoplasms ; genetics ; pathology

OBJECTIVETo investigate the effects of gossypol acetate on proliferation and apoptosis in Raji lymphoblastoid cells and explore the possible mechanism.

METHODSTrypan blue staining and ethyl thiazolyl diphenyl-tetrazolium bromide (MTT) assay were performed to measure the effect of gossypol acetate on the growth of Raji cells. The morphologic changes were observed with Wright's staining assay. Apoptosis was identified by agarose-gel electrophoresis and annexin V-FITC marked flow cytometry (FCM) analysis. The distribution of cell cycle, apoptosis rate, and Bcl-2 protein expression were analyzed by FCM. Caspase-3 activity was detected by colorimetric assay.

RESULTSGossypol acetate inhibited proliferation and induced apoptosis of Raji cells at concentration higher than 5 micromol/L. The effects were both dose- and time- dependent. Cycle analysis indicated the alteration of cell cycle and G0/G1 arrest. The activation of Caspase-3 was observed by colorimetric assay. The results of flow cytometry showed that the down-regulation of Bcl-2 protein expression and the activation of Caspase-3 seemed to occur simultaneously.

CONCLUSIONGossypol acetate can inhibit the growth of Raji cells and induce their apoptosis. The mechanism may be related to the alteration of cell cycle and the down-regulation of Bcl-2 protein expression.

Apoptosis ; drug effects ; Caspase 3 ; metabolism ; Cell Cycle ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Gossypol ; analogs & derivatives ; pharmacology ; Humans ; Proto-Oncogene Proteins c-bcl-2 ; metabolism

This study was aimed to investigate the effects of apogossypolone (ApoG2) on proliferative inhibition and apoptotic induction of multiple myeloma cells and its mechanism. The effects of ApopG2 on cell growth, cell viability, cell cycle and cell apoptosis were determined by Hoechst 33258 staining, DNA ladder formation and subdiploid peak analysis respectively. Cleavage of caspase-3 and caspase-9 was analyzed by colorimetric assay. Expression of BCL-2 and BCL-XL was detected by flow cytometry. The results indicated that the ApoG2 inhibited multiple myeloma cell proliferation in dose-and time-dependent manners, with IC(50) value to both U266 and Wusl cells at 0.1 and 0.2 micromol/L at 48 hours after treatment. ApoG2 effectively inhibited the proliferation of multiple myeloma cells, the IC(50) value in U266 cells and Wusl cells (at 48 hours) were 0.1 micromol/L and 0.2 micromol/L respectively. ApoG2 could induce the apoptosis of cells of myeloma in a time-dependent manner.The typical apoptotic morphological changes were observed under transmission electron microscope, while DNA ladder formation and remarkable peak of subdiploid cells appeared. ApoG2 could arrest the myeloma cells in G(2) phase, increasing from 9.7%(0 micromol/L) to 19.6% (10 micromol/L) in U266 cells and 9.8%(0 micromol/L) to 31.7% (10 micromol/L) in Wusl cells. ApoG2 could induce increase of caspase 9 and caspase 3 activity and down-regulate the expression of BCL-XL in U266 and Wusl cells, as well as the expression of BCL-2 in Wusl cells. It is concluded that ApoG2 has significant effect of antiproliferation and induction of apoptosis on multiple myeloma cells in vitro, ant its mechanisms may involve in down-regulation of BCL-2/BCL-XL and in change of cell cycle.
Apoptosis ; drug effects ; Caspase 3 ; metabolism ; Caspase 9 ; metabolism ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Gossypol ; analogs & derivatives ; pharmacology ; Humans ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; bcl-X Protein ; metabolism

This study was aimed to investigate the apoptosis effect of gossypol acetic acid on classic human multiple myeloma RPMI8226 cell line in vitro and its mechanism. The inhibitory effect on proliferation of RPMI8226 cells was evaluated by means of MTT assay. Cytotoxic effect and apoptosis was identified and analyzed with the aid of transmission electron microscopy, mitochondria membrane potential (MMP) and DNA gel electrophoresis. Meanwhile, Western-blot assay was used to detect the changes of several key cell apoptosis regulatory proteins such as BAX, caspase-3 and caspase-8 in these cells before and after treatment. The results showed that low concentrations of gossypol acetic acid (> 16 micromol/L) could suppress the proliferation and induce the apoptosis in RPMI8226 cells effectively. At the same time, gossypol acetic acid could also down-regulate the mitochondrial membrane potential, up-regulate the expression of the apoptosis-related protein such as BAX and caspase-3. It is concluded that the gossypol acetic acid can selectively induce proliferation inhibition and apoptosis of multiple myeloma RPMI8226 cells with a smaller dose.
Apoptosis ; drug effects ; Caspase 3 ; metabolism ; Caspase 8 ; metabolism ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Gossypol ; analogs & derivatives ; pharmacology ; Humans ; Membrane Potential, Mitochondrial ; Multiple Myeloma ; pathology ; bcl-2-Associated X Protein ; metabolism

Apogossypolone (ApoG2), a novel derivative of gossypol, has been shown to be a potent inhibitor of antiapoptotic Bcl-2 family proteins and to have antitumor activity in multiple types of cancer cells. Recent reports suggest that gossypol stimulates the generation of cellular reactive oxygen species (ROS) in leukemia and colorectal carcinoma cells; however, gossypol-mediated cell death in leukemia cells was reported to be ROS-independent. This study was conducted to clarify the effect of ApoG2-induced ROS on mitochondria and cell viability, and to further evaluate its utility as a treatment for nasopharyngeal carcinoma (NPC). We tested the photocytotoxicity of ApoG2 to the poorly differentiated NPC cell line CNE-2 using the ROS-generating TL/10 illumination system. The rapid ApoG2-induced cell death was partially reversed by the antioxidant N-acetyl-L-cysteine (NAC), but the ApoG2-induced reduction of mitochondrial membrane potential (MMP) was not reversed by NAC. In the presence of TL/10 illumination, ApoG2 generated massive amounts of singlet oxygen and was more effective in inhibiting cell growth than in the absence of illumination. We also determined the influence of light on the anti-proliferative activity of ApoG2 using a CNE-2-xenograft mouse model. ApoG2 under TL/10 illumination healed tumor wounds and suppressed tumor growth more effectively than ApoG2 treatment alone. These results indicate that the ApoG2-induced CNE-2 cell death is partly ROS-dependent. ApoG2 may be used with photodynamic therapy (PDT) to treat NPC.
Animals ; Antineoplastic Agents ; pharmacology ; Cell Death ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Gossypol ; analogs & derivatives ; pharmacology ; Humans ; Light ; Membrane Potential, Mitochondrial ; drug effects ; Mice ; Mice, Nude ; Nasopharyngeal Neoplasms ; metabolism ; pathology ; Neoplasm Transplantation ; Photochemotherapy ; Reactive Oxygen Species ; metabolism ; Singlet Oxygen ; metabolism ; Tumor Burden ; drug effects