Gossypol Research Articles

Preparation and Characterization of Gossypol Nanosuspensions

Gossypol (GP) is a kind of poorly water-soluble polyphenolic compounds. In this study, freeze dried gossypol nanosuspensions (GP-NS) were prepared by high-pressure homogenization and Freeze-drying technique. Bovine serum albumin (BSA) and D-alpha-tocopheryl polyethylene glycol succinate (TPGS) were used as stabilizing agents for the nanosuspensions while mannitol were used as lyophilized protecting medium. The physicochemical characteristics of the GP-NS were investigated when it was found that the mean particle size and zeta potential of the GP-NS were 217±23 nm and-21.4±2.7 mV, respectively, and the saturation solubility was 586.48±23.03 μg.mL-1. Differential scanning calorimetry and X-Ray Diffraction indicated that GP was in a crystalline state in nanosuspensions. GP-NS with a small particle size, and high saturation solubility, can be produced by the method described in this study.

Polymeric Micelles for Apoptosis-Targeted Optical Imaging of Cancer and Intraoperative Surgical Guidance

In a two-step strategy, an intraperitoneal (IP) injection of poly(ethylene glycol)-block-poly(ε-caprolactone) (PEG-b-PCL) micelles containing paclitaxel (PTX), cyclopamine (CYP), and gossypol (GSP) at 30, 30, and 30 mg/kg, respectively, debulked tumor tissues by 1.3-fold, based on loss of bioluminescence with <10% body weight change, and induced apoptosis in peritoneal tumors when used as neoadjuvant chemotherapy (NACT) in an ES-2-luc-bearing xenograft model for ovarian cancer. In a second step, a single intravenous (IV) injection of apoptosis-targeting GFNFRLKAGAKIRFGS-PEG-b-PCL micelles containing a near-infrared (NIR) fluorescence probe, DiR (1,1′-dioctadecyltetramethyl indotricarbocyanine iodide), resulted in increased peritoneal DiR accumulation in apoptosis-induced ES-2-luc tumor tissues (ex vivo) by 1.5-fold compared with DiR molecules delivered by methoxy PEG-b-PCL micelles (non-targeted) at 48 h after IV injection in a second step. As a result, a tandem of PEG-b-PCL micelles enabled high-resolution detection of ca. 1 mm diameter tumors, resulting in resection of approximately 90% of tumors, and a low peritoneal cancer index (PCI) of ca. 7. Thus, a tandem of PEG-b-PCL micelles used for NCAT and NIR fluorescence imaging of therapy-induced apoptosis for intraoperative surgical guidance may be a promising treatment strategy for metastatic ovarian cancer.

Quaternized chitosan-coated nanofibrous implants loaded with gossypol prepared by electrospinning and their efficacy against Graffi myeloid tumor

Nanofibrous poly(L-lactide-co-D,L-lactide) (coPLA) or coPLA/poly(ethylene glycol) implants loaded with plant polyphenolic compound gossypol (GOS) with anti-tumor activity were fabricated by electrospinning. Implants containing quaternized chitosan (QCh) were prepared by coating of the obtained fibrous materials with a thin film of cross-linked QCh. The morphology of the implants and chemical composition of the implant surface were studied by means of scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). In vitro cytotoxicity assay showed that GOS-loaded nanofibrous implants, both non-coated and QCh-coated displayed about two-fold higher inhibitory activity against Graffi tumor cells than that of free GOS at the 72nd h of incubation. As evidenced by the performed fluorescence microscopy analyses and SEM observations, the anti-tumor activity of the fibrous implants was mainly due to induction of apoptosis. The experiments in which the implants containing both QCh and GOS were placed locally into the tumor site after the tumor extirpation showed an increase in the survival rate and a lower rate of recurrence in the operative field and of metastases in regional lymph nodes. In this case, 40% of hamsters were alive on the 45th day of implantation and they did not show any clinical sign of recurrence in the operative field and metastases in the regional lymph nodes.

Effects of Gossypol on Reproduction and Hematology in Sheep

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Mecanismos da intoxicação do fígado de rato causada pelo gossipol

O fígado desempenha uma função central no metabolismo devido à sua interposição entre o trato digestivo e a circulação geral do organismo. Ele é também o principal órgão envolvido na biotransformação de substâncias exógenas (xenobióticos), com capacidade de converter compostos hidrofóbicos em hidrossolúveis, mais facilmente eliminados pelo organismo. O gossipol é uma substância fenólica tóxica presente na semente de algodão (Gossypium sp). Com o objetivo de estudar os mecanismos envolvidos na hepatotoxicidade do gossipol avaliou-se os seus efeitos no sistema antioxidante do fígado de ratos no que diz respeito ao estresse oxidativo e aspectos histopatológicos. Foram utilizados ratos machos da linhagem Wistar, separados em dois grupos, sendo que um recebeu óleo de canola (veículo, grupo Controle) e o outro recebeu gossipol na dosagem de 40 mg/kg de peso vivo do animal por 15 dias (grupo Tratado). O tratamento com gossipol promoveu alterações na atividade sérica das enzimas marcadoras de dano hepático e um significativo estresse oxidativo caracterizado pela diminuição nos níveis da glutationa reduzida (GSH) e consequente aumento da glutationa oxidada (GSSG), incluindo, ainda, danos à membrana plasmática e de organelas demonstrados pela peroxidação lipídica. O resultado da avaliação histopatológica demonstrou degeneração dos hepatócitos.

The Effect of Various Concentrations of Gossypol on The Rumen Protozoal Degradation of Grass Hay in Culture

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Research on Apoptosis of (-)-gossypol to Murine Cervical Cancer Xenograft and Its Mechanisms

Research on Apoptosis of (-)-gossypol to Murine Cervical Cancer Xenograft and Its Mechanisms

Quaternized chitosan-coated nanofibrous materials containing gossypol: Preparation by electrospinning, characterization and antiproliferative activity towards HeLa cells

Nanofibrous polylactide-based materials loaded with a natural polyphenolic compound gossypol (GOS) with antitumor properties were prepared by electrospinning. The nanofibrous materials were coated with a thin film of crosslinked quaternized chitosan (QCh). GOS incorporated in the nanofibrous mats was in the amorphous state. GOS release was diffusion-controlled and its in vitro release profiles depended on the mat composition. The nanofibrous materials exhibited high cytotoxicity towards HeLa tumor cells. Interestingly, it was particularly pronounced in the case of fibrous materials, which contain both QCh and GOS. The observed strong antiproliferative effect of the nanofibrous mats was mainly due to induction of cell apoptosis.

The role of COX‐2/PGE2 in gossypol‐induced apoptosis of colorectal carcinoma cells

Our previous study showed that gossypol (GOS) exhibits potent cytotoxic effects via apoptosis induction against human colorectal carcinoma cells; however, the role of cyclooxygenase (COX)-2/prostaglandin (PG)E(2) on GOS-induced apoptosis is still unknown. In the present study, 12-O-tetradecanoylphorbol-13-acetate (TPA) addition significantly inhibited GOS-induced apoptosis in human colorectal carcinoma HT-29 cells in accordance with inducing COX-2 protein/PGE(2) production. TPA inhibition of GOS-induced apoptosis was blocked by adding protein kinase (PK)C inhibitors including staurosporine (ST), GF109203X (GF), and H7, characterized by the occurrence of cleaved caspase 3 proteins and a decrease in COX-2 protein/PGE(2) production in HT-29 cells. The addition of COX activity inhibitors, including NS398 (NS), aspirin (AS), diclofenac (DI), and indomethacin (IN), suppressed TPA protection of GOS-induced apoptosis with decreased PGE(2) production in HT-29 cells. Application of PGE(2), but not it analogs PGD(2), PGJ(2), or PGF(2α), protected HT-29 cells from GOS-induced DNA ladders, and the E-prostanoid (EP(1)) receptor agonist, 17PT-PGE(2), mimicked the protection induced by PGE(2), whereas the selective EP(2) receptor agonist, butaprostol (BUT), the EP(3) receptor agonist, sulprostol (SUL), and the EP(4) receptor agonist, PGE(1) alcohol (PGE(1)), showed no significant effects on GOS-induced apoptosis in HT-29 cells. PGE(2) 's protection against GOS-induced apoptosis was reversed by adding the selective EP(1) receptor antagonist, SC-19220. Furthermore, GOS had an effective apoptotic effect on COLO205 colorectal carcinoma cells which expressed undetectable level of endogenous COX-2 protein than HT-29 cells, and the decreased COX-2 protein level via COX-2 siRNA or addition of COX-2 activity inhibitor NS significantly elevated GOS-induced cell death in HT-29 cells. COLO205-T cells were established through sustained TPA incubation of COLO205 cells, and COLO205-T cells showed a lower sensitivity to GOS-induced cell death with increased COX-2 (not Bcl-2 and Mcl-1) protein than parental COLO-205 cells. A decrease in COX-2 protein expression in COLO205-T cells by COX-2 siRNA transfection or enhanced GOS-induced cell death according to MTT assay and DNA integrity assay. The notion of COX-2/PGE(2) activation against GOS-induced apoptosis in colon carcinoma cells was demonstrated, and the combination of GOS and COX-2 inhibitors to treat colon carcinoma possesses clinical potential worthy of further investigation.

Apogossypolone Induces Autophagy of PC-3 Prostate Cancer Cells in vitro

Objective To study the growth inhibitation action of gossypol derivatives,ApoG2 on the prostatic cancer PC-3 cells,and make the primary study about their anti-tumor mechanism.Methods The MTT analytical method,AO staining,transmission electron microscope,flow cytometer and Western blot for measuring the apoptosis related proteins were used to study the growth inhibition and induction of autophagy roles of ApoG2 on the prostatic cancer PC-3 cells in vitro.Results When the concentration of ApoG2 was higher than 2.5 μg/ml in solution,it had the obvious proliferation inhibition ability to the prostate cancer PC-3 cells in vitro,and it had the charcteristics of time and dose dependent.When ApoG2 was used for the treatment of PC-3 cell for 72 hours,the observation with AO staining and transmission electron microscope indicated that ApoG2 could obviously induce the autophagy of prostate cancer cells.The measurement results by the flow cytometer indicated that the apoptosis of prostate cancer cells induced by ApoG2 might be strengthened by the use of autophagic inhibitor 3-MA.The measurement of Bcl-2 expressions by the Western blot found that after ApoG2 at the concentration of 10.0 μg/ml was used for treatment of prostate cancer cells for 48 hours,the expression level of Bcl-2 decreased.The Beclin 1 and LC-3Ⅱexpressions in the tumor cells were obviously increased by immunohistochemistry method after ApoG2 treatment.Conclusion ApoG2 has the same obvious anti-proliferation role to the prostatic cancer PC-3 cells in vitro and its mechanism is to mainly induce the autophagy of tumor cells and to secondarily induce their death,the inhibition of autophagy may promote the occurrence of death.

Abstract C34: The role of COX-2/PGE2 in gossypol-induced apoptosis of colorectal carcinoma cells

Abstract Our previous study has shown that gossypol (GOS) exhibited the potent cytotoxic effect via apoptosis induction against human colorectal carcinoma cells; however, the role of cyclooxygenase 2 (COX-2)/prostaglandin E2 on GOS-induced apoptosis is still unknown. In the present study, 12-O-tetradecanoylphorbol-13-acetate (TPA) addition significantly inhibited GOS-induced apoptosis in human colorectal carcinoma cells COLO205 in according with inducing COX-2 protein/PGE2 production. TPA inhibition of GOS-induced apoptosis was blocked by adding protein kinase C (PKC) inhibitors including ST, GF, and H7, characterized by an occurrence of cleaved caspase 3 proteins and a decrease in COX-2 protein/PGE2 production in COLO205 cells. Addition of COX activity inhibitors including NS398, aspirin (AS), diclofenac (DI), and indomethacin (IN) suppressed TPA protection of GOS-induced apoptosis with decreased PGE2 production in COLO205 cells. Application of PGE2, but not it analogues PGD2, PGJ2, and PGF2, protected COLO205 cells from GOS-induced DNA ladders, and the EP1 receptor agonist 17PT-PGE2 mimicked the protection by PGE2, whereas the selective EP2 receptor agonist butaprostol (BUT), EP3 receptor agonist sulprostol (SUL), and EP4 receptor agonist PGE1 alcohol (PGE1) showed no significant effect on GOS-induced apoptosis in COLO205 cells. PGE2 protection of GOS-induced apoptosis was reversed by adding a selective EP1 receptor antagonist SC-19220. Furthermore, GOS had less apoptotic effect on HT-29 colorectal carcinoma cells which expressed higher level of endogenous COX-2 protein than COLO205 cells, and decreased COX-2 protein level via COX-2 siRNA significantly elevated GOS-induced cell death in HT-29 cells. COLO205-T cells were established through sustained TPA incubation of COLO205 cells, and COLO205-T cells showed a lower sensitivity to GOS-induced cell death with increased COX-2 (not Bcl-2 and Mcl-1) protein than parental COLO-205 cells. A decrease in COX-2 protein expression in COLO205-T cells by COX-2 siRNA transfection enhanced GOS-induced cell death by MTT assay. The notion of COX-2/PGE2 activation against GOS-induced apoptosis in colon carcinoma cells was demonstrated, and combination of GOS and COX-2 inhibitors to treat colon carcinoma reserved clinical potential for further investigation. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the Second AACR International Conference on Frontiers in Basic Cancer Research; 2011 Sep 14-18; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2011;71(18 Suppl):Abstract nr C34.

Diversity of gossypol clathrates with pyrazine

Diversity of gossypol clathrates with pyrazine

H-bonding in clathrates bis-p-toluidine gossypol with DMFA and 1,4-dioxane

H-bonding in clathrates bis-<i>p</i>-toluidine gossypol with DMFA and 1,4-dioxane

Evaluation and identification of reliable reference genes for pharmacogenomics, toxicogenomics, and small RNA expression analysis

Pharmacogenomics, toxicogenomics, and small RNA expression analysis are three of the most active research topics in the biological, biomedical, pharmaceutical, and toxicological fields. All of these studies are based on gene expression analysis, which requires reference genes to reduce the variations derived from different amounts of starting materials and different efficiencies of RNA extraction and cDNA synthesis. Thus, accurate normalization to one or several constitutively expressed reference genes is a prerequisite to valid gene expression studies. Although selection of reliable reference genes has been conducted in previous studies in several animals and plants, no research has been focused on pharmacological targets, and very few studies have had a toxicological context. More interestingly, no studies have been performed to identify reference genes for small RNA analysis although small RNA, particularly microRNA (miRNA)-related research is currently one of the fastest-moving topics. In this study, using MCF-7 breast cancer cells as a model, we employed quantitative real-time PCR (qRT-PCR), one of the most reliable methods for gene expression analysis in many research fields, to evaluate and to determine the most reliable reference genes for pharmacogenomics and toxicogenomics studies as well as for small RNA expression analysis. We tested the transcriptional expression of five protein-coding genes as well as five non-coding genes in MCF-7 cells treated with five different pharmaceuticals or toxicants [paclitaxel (PTX), gossypol (GOS), methyl jasmonate (JAS), L-nicotine (NIC), and melamine (mela)] and analyzed the stability of the selected reference genes by four different methods: geNorm, NormFinder, BestKeeper, and the comparative ΔCt method. According to our analysis, a protein-coding gene, hTBCA and four non-coding genes, hRNU44, hRNU48, hU6, and hRNU47, appear to be the most reliable reference genes for the five chemical treatments. Similar results were also obtained in dose-response and time-course assays with gossypol (GOS) treatment. Our results demonstrated that traditionally used reference genes, such as 18s RNA, β-actin, and GAPDH, are not reliable reference genes for pharmacogenomics and toxicogenomics studies. In contrast, hTBCA and small RNAs are more stable during drug treatment, and they are better reference genes for pharmacogenomics and toxicogenomics studies. To widely use these genes as reference genes, these results should be corroborated by studies with other human cell lines and additional drugs classes and hormonal treatments.

Valproic acid synergistically enhances the cytotoxicity of gossypol in DU145 prostate cancer cells: An iTRTAQ-based quantitative proteomic analysis

Gossypol (GOS), a BH3 mimetic, has been investigated as a sensitizing co-therapy to radiation and chemotherapy in treatment of metastatic prostate cancer. In this study, we found that valproic acid (VPA), a histone deacetylase inhibitor (HDACI), counteracted the suppressive effect of GOS on histone H3 acetylation and enhanced the cytotoxicity of GOS to DU145 prostate cancer cells. Significant synergistic effects were observed in combined GOS and VPA treatment, culminating in more DNA damage and cell death. The iTRAQ-based quantitative proteomic analysis revealed differential proteomic profiles in cells treated with VPA, GOS or their combination. In GOS-treated cells, oxidative phosphorylation-related proteins were depressed and endoplasmic reticulum stress markers were upregulated. In the presence of VPA, the GOS-induced mitochondrial stress was further enhanced since glycolysis- and hypoxia-associated proteins were upregulated, suggesting a disruption of energy metabolism in these cells. Furthermore, the DNA damage repair ability of cells co-treated with GOS and VPA was also decreased, as evidenced by the downregulation of DNA damage repair proteins and the enhancement of DNA fragmentation and cell death. These findings suggest that GOS in combination with an HDACI has the potential to increase its clinical efficacy in the treatment of prostate cancer.

Anti‐amoebic Effect of Gossypol in Golden Hamsters with Experimental Hepatic Amoebic Abscess

Although metronidazole is an effective anti-amoebic medication, it is mutagenic and some strains of Entamoeba histolytica resistant to this drug have begun to appear. The search for new anti-amoebic compounds is, therefore, justified. We have previously found that gossypol has a potent in-vitro anti-amoebic effect; we now show that this compound is also effective in-vivo. Hamsters with experimental amoebic hepatic abscess were fed acetic acid gossypol (0–45 mg kg−1) or metronidazole (30 or 45 mg kg−1) for 5 or 10 days. The experimental amoebic hepatic abscess size and the in-vitro cell density reached by trophozoite cultures from the experimental amoebic hepatic abscesses were scored. Gossypol and metronidazole reduced the experimental amoebic hepatic abscess. The smallest effect of gossypol was obtained with 5–45 mg kg−1 (23–31% score reduction) administered for 5 days whereas the most effective treatment corresponded to 30 mg kg−1 gossypol for 10 days (90% score reduction). Gossypol at 45 mg kg−1 for 10 days was toxic. The anti-amoebic effect of 30 mg kg−1, judged as the cell density score reduction compared with the control group, was comparable with that produced by 30 mg kg−1 metronidazole administered for 10 days. Although in molar concentration terms, gossypol was nine times more potent than metronidazole, the margin between the most effective and lethal doses of gossypol was relatively narrow. A combination of gossypol and metronidazole could be a more efficacious and less toxic anti-amoebic combination than the separate drugs.

In-vitro Additive Synergistic Anti-amoebic Effect of a Metronidazole—Gossypol Blend

Gossypol has a potent anti-amoebic effect on both Entamoeba histolytica axenic cultures and experimental amoebic hepatic abscess. However, the margin between the in-vivo effective dose and the toxic dose in hamsters is relatively small. While metronidazole is widely used as an anti-amoebic medication, it is considered a possible carcinogen in man. With the aid of the Basic Sequential Analytical Simplex Method we tested the effectiveness of 12 metronidazole-gossypol blends where the concentration of each drug was systematically varied. Amoebic growth inhibition was observed (33–71% with respect to controls) using blends containing metronidazole (50–154 nM) and gossypol (5–16 nM). The combination containing metronidazole (88.61 nM) and gossypol (9.95 nM) caused 62% amoebic growth inhibition. These concentrations where 50% lower than those required to produce an equivalent effect using metronidazole or gossypol alone. Thus, the actions of metronidazole and gossypol against E. histolytica are additive. Accordingly, the in-vivo application of an appropriate combination of metronidazole and gossypol could be as effective as each drug alone, but less toxic to the host.

In‐vitro Giardia lamblia Growth Inhibition by Gossypol

The inhibitory effect of gossypol on Giardia lamblia growth was tested in-vitro. Parasites were cultivated in axenic conditions, in TYI-S-33 medium. Varying doses of gossypol (0–100 μM) were added to culture tubes containing 5.5mL TYI-S-33 inoculated with 103 trophozoites mL−1 and incubated at 36°C, for 72 h. The percentage growth inhibition, with respect to untreated cultures was expressed as probit values, plotted as a function of the logarithm of gossypol doses, and analysed by linear regression. The 50% growth inhibition (IC50) was 69.74 ± 3.44 μM and the 95% confidence limits were 62.99–76.49 μM. Gossypol was toxic to G. lamblia. This species is the most resistant parasitic protozoa to this drug tested to date. Several strategies to increase the effectiveness of gossypol against G. lamblia are suggested.

Effect of gossypol on blood serum parameters and small intestinal morphology of male broilers

Summary In the present study, the effect of varied gossypol (GOSS) amounts was investigated on blood parameters, the digesta pH, villus height, villus width, and crypta depth, width of duodenum, jejunum and ileum. A total of one hundred eight Ross 308 male broilers were fed with four diet groups as follows: no gossypol (control), gossypol rate 62 mg/kg (GOSS 62), gossypol rate 124 mg/kg (GOSS 124) and gossypol rate 186 mg/kg (GOSS 186). The effect of used gossypol amounts on blood parameters was not found to be statistically significant. Increases in digesta pH values of jejunum and ileum with GOSS 186 diet group were found to be statistically significant. The results also indicated that, except duodenum villus height, there was no statistical difference effect of GOSS on epithelial cell thickness, villus height, villus width, crypta depth and crypta width of the duodenum, jejunum and ileum. There have been no clearly negative effects of higher gossypol amounts up to 186 mg/kg diets on these parameters.

Effect of L-gossypol on apoptosis in human nasopharyngeal carcinoma cell

Objective To investigate the apoptosis-inducing effect of L-gossypol on human nasopharyngesl carcinoma cell line CNE2 and its possible mechanism.Methods The effect of L-gossypol on proliferation of CNE2 cells was estimated by MTT assay.Flow cytometry was used to analyz cell apoptosis induced by(-)-gossypol and the expression of Bcl-2 、Bax proteins.Caspase-3 activity was determined by caspase-3 colorimetric assay kit.Results Lgossypol was able to inhibit the proliferation of CNE2 cells in a dose-dependent and time-dependent fashion at concentrations more than 10 μmoL/L.L-gossypol regulated cell cycle and GO/G1 arrest could be observed in CNE2 cells.In the process of apoptosis,the expression of Bcl-2 was down-regulated and Bax was up-regulated,caspase-3 activity was in peak at 24h.Conclusion L-gossypol could induce apoptosis in nasopharyngeal carcinoma cell line CNE2 in vitro,which may be associated with down-regulation of Bcl-2,up-regulation of Bax genes expression and caspase-3 activation. Key words: L-gossypol; Nasopharyngeal neoplasms; Cell apoptosis