Solamargine purified from Solanum incanum Chinese herb triggers gene expression of human TNFR I which may lead to cell apoptosis

Unleashed Treasures of Solanaceae: Mechanistic Insights into Phytochemicals with Therapeutic Potential for Combatting Human Diseases

Plants that possess a diverse range of bioactive compounds are essential for maintaining human health and survival. The diversity of bioactive compounds with distinct therapeutic potential contributes to their role in health systems, in addition to their function as a source of nutrients. Studies on the genetic makeup and composition of bioactive compounds have revealed them to be rich in steroidal alkaloids, saponins, terpenes, flavonoids, and phenolics. The Solanaceae family, having a rich abundance of bioactive compounds with varying degrees of pharmacological activities, holds significant promise in the management of different diseases. Investigation into Solanum species has revealed them to exhibit a wide range of pharmacological properties, including antioxidant, hepatoprotective, cardioprotective, nephroprotective, anti-inflammatory, and anti-ulcerogenic effects. Phytochemical analysis of isolated compounds such as diosgenin, solamargine, solanine, apigenin, and lupeol has shown them to be cytotoxic in different cancer cell lines, including liver cancer (HepG2, Hep3B, SMMC-772), lung cancer (A549, H441, H520), human breast cancer (HBL-100), and prostate cancer (PC3). Since analysis of their phytochemical constituents has shown them to have a notable effect on several signaling pathways, a great deal of attention has been paid to identifying the biological targets and cellular mechanisms involved therein. Considering the promising aspects of bioactive constituents of different Solanum members, the main emphasis was on finding and reporting notable cultivars, their phytochemical contents, and their pharmacological properties. This review offers mechanistic insights into the bioactive ingredients intended to treat different ailments with the least harmful effects for potential applications in the advancement of medical research.

Cancer and apoptosis: The apoptotic activity of plant and marine natural products and their potential as targeted cancer therapeutics

Cancer is a multifactorial, multi-stage disease, including complex cascades of signaling pathways—the cell growth governed by dysregulated and abrupt cell division. Due to the complexity and multi-regulatory cancer progression, cancer is still a challenging disease to treat and survive. The screening of extracts and fractions from plants and marine species might lead to the discovery of more effective compounds for cancer therapeutics. The isolated compounds and reformed analogs were known as future prospective contenders for anti-cancer chemotherapy. For example, Taxol, a potent mitotic inhibitor discovered from Taxus brevifolia, suppresses cell growth and arrest, induces apoptosis, and inhibits proliferation. Similarly, marine sponges show remarkable tumor chemo preventive and chemotherapeutic potential. However, there is limited research to date. Several plants and marine-derived anti-cancer compounds having the property to induce apoptosis have been approved for clinical trials. The anti-cancer activity kills the cell and slows the growth of cancer cells. Among cell death mechanisms, apoptosis induction is a more profound mechanism of cell death triggered by naturally isolated anti-cancer agents. Evading apoptosis is the major hurdle in killing cancer cells, a mechanism mainly regulated as intrinsic and extrinsic. However, it is possible to modify the apoptosis-resistant phenotype of the cell by altering many of these mechanisms. Various extracts and fractions successfully induce apoptosis, cell-cycle modulation, apoptosis, and anti-proliferative activity. Therefore, there is a pressing need to develop new anti-cancer drugs of natural origins to reduce the effects on normal cells. Here, we’ve emphasized the most critical elements: i) A better understanding of cancer progression and development and its origins, ii) Molecular strategies to inhibit the cell proliferation/Carcino-genesis, iii) Critical regulators of cancer cell proliferation and development, iv) Signaling Pathways in Apoptosis: Potential Targets for targeted therapeutics, v) Why Apoptosis induction is mandatory for effective chemotherapy, vi) Plants extracts/fractions as potential apoptotic inducers, vii) Marine extracts as Apoptotic inducers, viii) Marine isolated Targeted compounds as Apoptotic inducers (FDA Approved/treatment Phase). This study provides a potential therapeutic option for cancer, although more clinical studies are needed to verify its efficacy in cancer chemotherapy.

Chemoresistant ovarian cancer enhances its migration abilities by increasing store-operated Ca2+ entry-mediated turnover of focal adhesions

Background

Among gynecological cancers, ovarian carcinoma has the highest mortality rate, and chemoresistance is highly prevalent in this cancer. Therefore, novel strategies are required to improve its poor prognosis. Formation and disassembly of focal adhesions are regulated dynamically during cell migration, which plays an essential role in cancer metastasis. Metastasis is intricately linked with resistance to chemotherapy, but the molecular basis for this link is unknown.

Methods

Transwell migration and wound healing migration assays were used to analyze the migration ability of ovarian cancer cells. Real-time recordings by total internal reflection fluorescence microscope (TIRFM) were performed to assess the turnover of focal adhesions with fluorescence protein-tagged focal adhesion molecules. SOCE inhibitors were used to verify the effects of SOCE on focal adhesion dynamics, cell migration, and chemoresistance in chemoresistant cells.

Results

We found that mesenchymal-like chemoresistant IGROV1 ovarian cancer cells have higher migration properties because of their rapid regulation of focal adhesion dynamics through FAK, paxillin, vinculin, and talin. Focal adhesions in chemoresistant cells, they were smaller and exhibited strong adhesive force, which caused the cells to migrate rapidly. Store-operated Ca²⁺ entry (SOCE) regulates focal adhesion turnover, and cell polarization and migration. Herein, we compared SOCE upregulation in chemoresistant ovarian cancer cells to its parental cells. SOCE inhibitors attenuated the assembly and disassembly of focal adhesions significantly. Results of wound healing and transwell assays revealed that SOCE inhibitors decreased chemoresistant cell migration. Additionally, SOCE inhibitors combined with chemotherapeutic drugs could reverse ovarian cancer drug resistance.

Conclusion

Our findings describe the role of SOCE in chemoresistance-mediated focal adhesion turnover, cell migration, and viability. Consequently, SOCE might be a promising therapeutic target in epithelial ovarian cancer.

Graphical abstract

Solamargine inhibits gastric cancer progression by regulating the expression of lncNEAT1_2 via the MAPK signaling pathway

Solamargine, a derivative from the steroidal solasodine in Solanum species, has exhibited anticancer activities in numerous types of cancer; however, its role in gastric cancer (GC) remains unknown. In the present study, it was demonstrated that Solamargine suppressed the viability of five gastric cancer cell lines in a dose‑dependent manner and induced notable alterations in morphology. Treatment with Solamargine promoted cell apoptosis (P<0.01). Solamargine increased the expression of long noncoding RNA (lnc) p53 induced transcript and lnc nuclear paraspeckle assembly transcript 1 (NEAT1)_2 (P<0.01) in GC by reducing the phosphorylation of extracellular signal‑regulated kinase (Erk)1/2 mitogen‑activated protein kinase (MAPK). To gain insight into the potential mechanism, an Erk1/2 inhibitor (U0126) was applied. The results revealed that lncNEAT1_2 expression levels increased, which was consistent with the effects of Solamargine. Downregulation of lncNEAT1_2 in GC cells revealed no effect on the expression levels of total Erk1/2 and, and counteracted the effect of Solamargine. Solamargine was observed to increase the expression of lncNEAT1_2 via the Erk1/2 MAPK signaling pathway. Of note, the knockdown of lncNEAT1_2 reduced the inhibitory effect of Solamargine (P<0.05). Additionally, experiments in vivo and in primary GC cells from patients demonstrated that Solamargine significantly suppressed tumor growth (P<0.05). In vivo analysis of a xenograft mouse model further supported that Solamargine could induce the apoptosis of cancer cells in tumor tissue as observed by a terminal deoxynucleotidyl transferase‑mediated dUTP‑biotin nick end labeling and H&E staining (P<0.05). Experiments in primary GC cells from patients verified the anti‑tumor effect of Solamargine. In summary, the findings of the present study indicated that Solamargine inhibited the progression of GC by regulating lncNeat1_2 via the MAPK pathway.

Solanum incanum extract (SR-T100) induces melanoma cell apoptosis and inhibits established lung metastasis

Melanoma, a cancer derived from melanocytes, is one of the most chemoresistant cancers and tends to metastasize. Once it metastasizes, the prognosis is poor. Even with the recent advancement of targeted therapy and immunotherapy, the prognosis remains discouraging. SR-T100, a Solanum incanum extract, shows anticancer effects against several cancers; however, its therapeutic efficacy against melanoma and established metastasis remains unknown. In this study, we showed that SR-T100 induces apoptosis, DNA damage, and G0/G1 cell cycle arrest in murine B16 melanoma cells in vitro. In vivo, intralesional injection of SR-T100 decreased the tumor size of the regional melanoma in the foot pad. Moreover, intraperitoneal injection of SR-T100 inhibited the growth and the number of established melanoma metastases in the lungs. Our study highlights SR-T100 as a potential novel treatment for established tumors from regional and metastatic melanoma.

Solanum Incanum Extract Downregulates Aldehyde Dehydrogenase 1-Mediated Stemness and Inhibits Tumor Formation in Ovarian Cancer Cells

Solanum incanum extract (SR-T100), containing the active ingredient solamargine, can induce apoptosis via upregulation of tumor necrosis factor receptor expression and activation of the mitochondrial apoptosis pathway, and has therapeutic effects in patients with actinic keratosis. Here, we evaluate the novel molecular mechanisms underlying SR-T100-regulated stemness and chemoresistance. The concentration of SR-T100 that inhibited 50% cell viability (IC₅₀) was lower in ovarian cancer cells than in nonmalignant cells. Furthermore, the SR-T100 IC₅₀ in chemoresistant cells was similar to the IC₅₀ in chemosensitive cells. Additionally, SR-T100 increased cisplatin and paclitaxel sensitivity in chemoresistant cells. SR-T100 downregulated the expression of stem cell markers, including aldehyde dehydrogenase 1 (ALDH1), Notch1, and FoxM1, and reduced sphere formation in ovarian cancer cells. Using microarray analyses, immunoblotting, luciferase activity, and chromatin immunoprecipitation (ChIP) assays, we showed that SR-T100 suppressed the expression of c/EBPβ and COL11A1, and its promoter activity, in resistant cells, but not sensitive cells. SR-T100, paclitaxel, and cisplatin inhibited the growth of A2780CP70 cells in mouse xenografts, as compared to the vehicle control, and the combination of cisplatin and SR-T100 was more effective than either treatment alone. SR-T100 may represent a potential therapeutic adjunct to chemotherapy for ovarian cancer treatment.

Traditional Chinese medicine for prevention and treatment of hepatocarcinoma: From bench to bedside

Traditional Chinese medicine (TCM) has played a positive role in the management of hepatocarcinoma. Hepatocarcinoma patients may present Qi-stagnation, damp-heat, blood stasis, Qi-deficiency, Yin-deficiency and other TCM syndromes (Zheng). Modern treatments such as surgery, transarterial chemoembolization (TACE) and high intensity focus ultrasound treatment would influence the manifestation of TCM syndromes. Herbs with traditional efficacy of tonifying Qi, blood and Yin, soothing liver-Qi stagnation, clearing heat and detoxifying and dissolving stasis, have been demonstrated to be potent to prevent hepatocarcinogenesis. TCM has been widely used in all aspects of integrative therapy in hepatocarcinoma, including surgical resection, liver transplantation, TACE, local ablative therapies and even as monotherapy for middle-advanced stage hepatocarcinoma. Clinical practices have confirmed that TCM is effective to alleviate clinical symptoms, improve quality of life and immune function, prevent recurrence and metastasis, delay tumor progression, and prolong survival time in hepatocarcinoma patients. The effective mechanism of TCM against hepatocarcinoma is related to inducing apoptosis, autophagy, anoikis and cell senescence, arresting cell cycle, regulating immune function, inhibiting metastasis and angiogenesis, reversing drug resistance and enhancing effects of chemotherapy. Along with the progress of research in this field, TCM will contribute more to the prevention and treatment of hepatocarcinoma.

Therapeutic Potential of Steroidal Alkaloids in Cancer and Other Diseases

Steroidal alkaloids are a class of secondary metabolites isolated from plants, amphibians, and marine invertebrates. Evidence accumulated in the recent two decades demonstrates that steroidal alkaloids have a wide range of bioactivities including anticancer, antimicrobial, anti-inflammatory, antinociceptive, etc., suggesting their great potential for application. It is therefore necessary to comprehensively summarize the bioactivities, especially anticancer activities and mechanisms of steroidal alkaloids. Here we systematically highlight the anticancer profiles both in vitro and in vivo of steroidal alkaloids such as dendrogenin, solanidine, solasodine, tomatidine, cyclopamine, and their derivatives. Furthermore, other bioactivities of steroidal alkaloids are also discussed. The integrated molecular mechanisms in this review can increase our understanding on the utilization of steroidal alkaloids and contribute to the development of new drug candidates. Although the therapeutic potentials of steroidal alkaloids look promising in the preclinical and clinical studies, further pharmacokinetic and clinical studies are mandated to define their efficacy and safety in cancer and other diseases.

Induction of apoptosis in human hepatoma SMMC-7721 cells by solamargine from Solanum nigrum L

ETHNOPHARMACOLOGICAL RELEVANCE

Solanum nigrum L. (SNL), a traditional Chinese medicinal herb endowed with diuretic, antipyretic and hepatoprotective effects, has been used as a major ingredient of folk prescriptions for anticancer treatment in China.

AIM OF THE STUDY

The purpose of this study was to evaluate the inhibitory effect of solamargine (SM), a major steroidal alkaloid glycoside purified from SNL, on human hepatoma SMMC-7721 cells and investigate the possible mechanism of SM.

MATERIALS AND METHODS

The MTT assay was used to evaluate the IC(50) on tumor cell lines. The effect on morphology was observed with a light or fluorescence microscopy. The rate of apoptosis and the cell cycle were measured using flow cytometry (FCM). The expression of caspase-3 protein was measured by colorimetric assay.

RESULTS

SM significantly inhibited the growth of SMMC-7721 and HepG2 cells and induced cell apoptosis. Cell cycle analysis revealed that SM caused cell cycle arrest at the G2/M phase. Moreover, SM could up-regulate the expression of caspase-3.

CONCLUSIONS

This study indicated that SM exerted potential anticancer activity on SMMC-7721 cells in vitro through the activation of caspase-3 and the regulation of the cell cycle progression to induce apoptosis and inhibit hepatoma cells proliferation.

Solanum incanum extract (SR-T100) induces human cutaneous squamous cell carcinoma apoptosis through modulating tumor necrosis factor receptor signaling pathway

BACKGROUND

The Solanum species herbs have been used to treat cancer for centuries; however, the underlying mechanisms and effectiveness in vivo remain unclear.

OBJECTIVES

SR-T100, extracted from the Solanum incanum, contains solamargine alkaloid as the main active ingredient. Here, we investigated the apoptosis-inducing effects of SR-T100 for targeting squamous cell carcinoma (SCC) in vitro and in vivo.

METHODS

We elucidated the mechanism by which SR-T100 induces apoptosis of human SCCs (A431, SCC4, SCC9, and SCC25) cells. The efficacy and safety issues were addressed regarding topical treatment of SR-T100 on UVB-induced cutaneous SCC of hairless mice and actinic keratoses (AKs) of human.

RESULTS

SR-T100 induces apoptosis in human SCCs cell lines by up-regulating the expressions of tumor necrosis factor receptors (TNFRs) and Fas, and downstream adaptors FADD/TRADD of the TNF-α and Fas ligand signaling cascades. SR-T100 also triggered the mitochondrial apoptotic pathway, as up-regulated cytochrome c and Bax, down-regulated Bcl-X(L). Animal experiments showed that all papillomas (35/35) and 27 of 30 UVB-induced microinvasive SCCs in hairless mice disappeared within 10 weeks after once-daily application of topical SR-T100. Furthermore, 13 patients, who suffered with 14 AKs, were treated with once-daily topical SR-T100 gel and 10 AKs cured after 16 weeks, showing negligible discomforts.

CONCLUSION

Our studies indicate that SR-T100 induces apoptosis of SCC cells via death receptors and the mitochondrial death pathway. The high efficacy of SR-T100 in our preclinical trial suggests that SR-T100 is a highly promising herb for AKs and related disorders.

Phytochemicals: cancer chemoprevention and suppression of tumor onset and metastasis

Carcinogenesis is a multi-step process which could be prevented by phytochemicals. Phytochemicals from dietary plants and other plant sources such as herbs are becoming increasingly important sources of anticancer drugs or compounds for cancer chemoprevention or adjuvant chemotherapy. Phytochemicals can prevent cancer initiation, promotion, and progression by exerting anti-inflammatory and anti-oxidative stress effects which are mediated by integrated Nrf2, NF-kappaB, and AP-1 signaling pathways. In addition, phytochemicals from herbal medicinal plants and/or some dietary plants developed in recent years have been shown to induce apoptosis in cancer cells and inhibition of tumor growth in vivo. In advanced tumors, a series of changes involving critical signaling molecules that would drive tumor cells undergoing epithelial-mesenchymal transition and becoming invasive. In this review, we will discuss the potential molecular targets and signaling pathways that mediate tumor onset and metastasis. In addition, we will shed light on some of the phytochemicals that are capable of targeting these signaling pathways which would make them potentially applicable to cancer chemoprevention, treatment and control of cancer progression.

Lupeol, a dietary triterpene, inhibited growth, and induced apoptosis through down-regulation of DR3 in SMMC7721 cells

Lupeol (Lup-20(29)-en-3H-ol), a novel dietary triterpene, was found in fruits, vegetables, and several medicinal plants. Here, we investigated its growth-inhibitory effect and associated mechanisms in hepatocellular carcinoma SMMC7721 cells. Lupeol treatment resulted in significant inhibition of cell viability in a dose-dependent manner and caused apoptotic death of this cell line with activation of caspase3 expression. Caspase8 inhibitor pretreatment was found to partially block the apoptosis induced by Lupeol. Moreover, Lupeol specifically caused a significant decrease in the expression of Death receptor 3 (DR3) mRNA and protein and a significant elevated expression of FADD mRNA whereas Fas mRNA and protein expression was not detectable. Further more, knockdown of DR3 by small interfering RNA inhibited the growth and induced apoptosis of hepatocellular carcinoma cell. These results suggested that Lupeol treatment induced growth inhibition and apoptosis in SMMC7721 cells, the mechanism is due to down-regulation of DR3 expression. We demonstrated that Lupeol appears to be a promising chemopreventive agent for treating hepatocellular carcinoma, and DR3 may be an important target for liver cancer therapy.

LC-MS analysis of solanidane glycoalkaloid diversity among tubers of four wild potato species and three cultivars (Solanum tuberosum)

Secondary metabolites in potato tubers include both phytonutrients and plant defense compounds. The extent these small molecules vary among different potato genotypes is not well characterized. LC-MS analysis of tuber extracts from seven potato genotypes showed that one large source of small molecule variation is the glycoalkaloids. Glycoalkaloids are involved in the resistance of potatoes to pathogens and pests, but they also have implications for human health and nutrition. This study focused on glycoalkaloids with solanidane or solanidane-like aglycones, of which over 50 were tentatively identified, many of which appeared to be novel glycoalkaloids. Results suggested the variety of glycoalkaloids in potatoes is considerably greater than previously thought. Dissecting the role of these many glycoalkaloids in human health or pest and pathogen resistance will be a formidable undertaking.

Synthesis of neosaponins and neoglycolipids containing a chacotriosyl moiety

Alpha-L-rhamnopyranosyl-(1-->4)-[alpha-L-rhamnopyranosyl-(1-->2)]-beta-D-glucopyranose (chacotriose) is the oligosaccharide moiety of dioscin. Chacotriosyl trichloroacetimidate was synthesized from d-glucose and l-rhamnose, and glycosylated to mevalonate (diosgenin, cholesterol, and glycyrrhetic acid) to yield dioscin and neosaponins. In order to simplify the structure of the aglycone part, the mevalonate moiety was replaced with double-chain neoglycolipids that mimicked glycosyl ceramides. A cytotoxicity test revealed the importance of the glycosidic linkage of the naturally occurring beta-form and that dioscin and the neoglycolipid with the longest chain showed a moderate activity.

Antitumor efficacy of the novel chemotherapeutic agent coramsine is potentiated by cotreatment with CpG-containing oligodeoxynucleotides

Coramsine is a novel chemotherapeutic agent isolated from Solanum linnaeanum (devil's apple). Topical treatment provides clinical benefit for skin tumors. To evaluate the potential broader applicability of the drug, its in vivo anticancer efficacy in a murine model of malignant mesothelioma and its mode of action were investigated. Systemic administration of coramsine slowed tumor growth and prolonged survival time. Importantly, the antitumor efficacy of coramsine was enhanced when treatment was combined with stimulation of innate immunity using unmethylated CpG-containing oligodeoxynucleotides (ODNs). Combination treatment further slowed tumor growth and provided a survival benefit. Coramsine seems to kill tumor cells by direct cell lysis. Using 2 different assays to detect apoptosis (caspase activation and DNA fragmentation), we found no evidence that coramsine induces any form of programmed cell death. The fact that the efficacy of coramsine is potentiated by CpG ODNs suggests that coramsine-induced cell death is an immunologic null event.

Anti-inflammatory activity of herbal medicines: inhibition of nitric oxide production and tumor necrosis factor-alpha secretion in an activated macrophage-like cell line

Houttuynia cordata Thunb. (HC), Glycyrrhiza uralensis Fischer (GU), Forsythia suspense (Thunb.) Vahl (FS), and Lonicera japonica Thunb. (LJ) are Chinese herbs known to possess anti-inflammatory properties. The effects of aqueous extracts of these herbs on the production of the pro-inflammatory mediators, nitric oxide (NO) and tumor necrosis factor-alpha (TNF-alpha) were examined in an activated macrophage-like cell line, RAW 264.7 cells. Aqueous extracts from FS at 0.0625-2.0 mg/ml inhibited in vitro production of NO and secretion of TNF-alpha in a dose-dependent manner. FS at 1.0-2.0 mg/ml and 0.125-2.0 mg/ml significantly inhibited NO production and TNF-alpha, respectively. An extract of LJ demonstrated potent inhibition of both NO production and TNF-alpha secretion in a dose-dependent manner. An aqueous extract from HC inhibited NO production in a dose-dependent manner, but minimally (approximately 30%) inhibited TNF-a secretion at 0.0625 and 0.125 mg/ml. In contrast, an aqueous extract of GU had a minimal effect on both the production of NO and the secretion of TNF-alpha. Viability of cells at all concentrations studied was unaffected as determined by MTT cytotoxicity assay and trypan blue dye exclusion. These results suggest that aqueous extracts from FS, LJ and HC have anti-inflammatory actions as measured by inhibition of NO production and/or TNF-alpha secretion.

Regression of hepatocellular carcinoma spontaneous or herbal medicine related?

Hepatocellular carcinoma is one of the most common causes of death from cancer in Taiwan. Treatments for this disease include surgical resection, transcatheter arterial embolization, chemoembolization and systemic chemotherapy. Without treatment, the prognosis of hepatocellular carcinoma is poor, and mortality continues to be significant even in patients with small tumors detected during follow-up. For patients in Taiwan with advanced hepatocellular carcinoma, traditional herbal medicine is frequently used. However, neither the overall prevalence of this therapy nor its efficacy has been studied systematically. Spontaneous regression of cancer, although rare, may occur, but the mechanism leading to regression is still far from understood. Here, we report a case of hepatocellular carcinoma with complete regression after taking herbal medicine. We cannot be certain how significant the herbal preparation was in the regression of the hepatocellular carcinoma, but the regression of the tumor provides us a reason and hope for further research.

Action of solamargine on human lung cancer cells--enhancement of the susceptibility of cancer cells to TNFs

Solamargine (SM), isolated from Solanum incanum herb, displayed a superior cytotoxicity in four human lung cancer cell lines. The half-inhibitory concentrations (IC50), of the cell viability assay for H441, H520, H661 and H69 cells were 3, 6.7, 7.2 and 5.8 microM, respectively. SM-induced apoptosis of these cells by PS externalization in a dose-dependent manner and increased sub-G1 fraction were observed. Quenching of the expression of tumor necrosis factor receptors (TNFRs) during the progress of human lung carcinogenesis has been previously reported. SM may induce cell apoptosis via modulating the expression of TNFRs and their subsequent TRADD/FADD signal cascades. Subsequently, SM treatment increased the binding activities of TNF-alpha and TNF-beta to the lung cancers, and the intrinsic TNFs-resistant cancer cells became susceptible to TNF-alpha and -beta. In addition, SM caused release of cytochrome c, downregulation of anti-apoptotic Bcl-2 and Bcl-xL, increase of caspase-3 activity, and DNA fragmentation. Thus, SM could modulate the expressions of TNFRs and Bcl-2, and might be a potential anticancer agent for TNFs and Bcl-2 related resistance of human lung cancer cells.

The cytotoxic activity of the total alkaloids isolated from different parts of Solanum pseudocapsicum

The total alkaloid fractions of the methanolic extracts of the leaves, ripe fruits, roots, seeds and stem of Solanum pseudocapsicum were subjected to in-vitro cytotoxicity, short-term toxicity and long-term survival studies. All the five fractions exhibited potent activity. The total alkaloid fraction of leaves was found to be the most potent. The HT-29 cell line was the most sensitive to the fractions. The cytotoxic concentration (CTC(50)) values for all these fractions ranged between 0.39-0.91, 0.68-2.8, 0.92-3.56, 4.05-8.2, 3.28-5.65 and 0.95-5.55 microg/ml, respectively for HT-29, RD-228, A-549, HEp-2, B(16)F(10) and Vero cell lines. In short-term toxicity studies, the fractions showed 50% viability at 93-128 microg/ml for DLA cells and 141-189 microg/ml for human lymphocytes. In the long-term survival studies on the cell lines RD-228, HEp-2 and Vero, cells retained their regenerative capacities at concentrations below 8 microg/ml. The total alkaloids of the plant, especially from the leaves merit further investigations to identify the active constituents in animal models.

Evaluation of clastogenic potential of the antimalarial plantSolanum nudum

Compounds isolated from Solanum nudum have shown in vitro antimalarial activity against the FCB-2 strain of Plasmodium falciparum. Diosgenone (C27H40O3) the main component isolated from the hexane extract and an aqueous extract were evaluated to measure their clastogenic potential using the micronucleus test. Three concentrations (16, 32 and 64 g/kg of weight) of the aqueous extract were administered intraperitoneally into mice, (the highest concentration corresponded to 80% LD50) and diosgenone solubilized in olive oil was inoculated at the highest concentration possible (11.187 g/kg of weight). After administration of the compounds, no induction of micronucleus was observed either in polychromatic or normochromatic erythrocytes. Interestingly, a reduction of 51% in the young/mature erythrocytes ratio was seen in cells treated with aqueous extract. We conclude that neither diosgenone nor the aqueous extract have clastogenic activity, and that the aqueous extract showed some toxicity at the above mentioned concentrations. These results are significant since diosgenone could be a new therapeutic alternative for the treatment of malaria.

Granulocyte macrophage-colony stimulating factor and interleukin-3 increase expression of type II tumour necrosis factor receptor, increasing susceptibility to tumour necrosis factor-induced apoptosis. Control of leukaemia cell life/death switching

Tumour necrosis factor (TNF) induces apoptosis in a range of cell types via its two receptors, TNFR1 and TNFR2. Here, we demonstrate that proliferation and TNFR2 expression was increased in human leukaemic TF-1 cells by granulocyte macrophage-colony stimulating factor (GM-CSF) and interleukin-3 (IL-3), with TNFR1 expression unaffected. Consequently, they switch from a proliferative to a TNF-induced apoptotic phenotype. Raised TNFR2 expression and susceptibility to TNF-induced apoptosis was not a general effect of proliferation as IL-1beta and IFN-gamma both proliferated TF-1 cells with no effect on TNFR expression or apoptosis. Although raised TNFR2 expression correlated with the apoptotic phenotype, stimulation of apoptosis in GM-CSF-pretreated cells was mediated by TNFR1, with stimulation of TNFR2 alone insufficient to initiate cell death. However, TNFR2 did play a role in apoptotic and proliferative responses as they were blocked by the presence of an antagonistic TNFR2 antibody. Additionally, coincubation with cycloheximide blocked the mitotic effects of GM-CSF or IL-3, allowing only the apoptotic responses of TNF to persist. TNF life/death was also observed in K562, but not MOLT-4 and HL-60 human leukaemic cell types. These findings show a cooperative role of TNFR2 in the TNF life/death switching phenomenon.

Rhein induces apoptosis in HL-60 cells via reactive oxygen species-independent mitochondrial death pathway

Rhein is an anthraquinone compound enriched in the rhizome of rhubarb, a traditional Chinese medicine herb showing anti-tumor promotion function. In this study, we first reported that rhein could induce apoptosis in human promyelocytic leukemia cells (HL-60), characterized by caspase activation, poly(ADP)ribose polymerase (PARP) cleavage, and DNA fragmentation. The efficacious induction of apoptosis was observed at 100 microM for 6h. Mechanistic analysis demonstrated that rhein induced the loss of mitochondrial membrane potential (DeltaPsi(m)), cytochrome c release from mitochondrion to cytosol, and cleavage of Bid protein. Rhein also induced generation of reactive oxygen species (ROS) and the phosphorylation of c-Jun N-terminal kinase (JNK) and p38 kinase. However, these actions seem not to be associated with the apoptosis induction because antioxidants including N-acetyl cysteine (NAC), Tiron, and catalase did not block rhein-induced apoptosis, although they could block the generation of ROS and the phosphorylation of JNK and p38 kinase. Our data demonstrate that rhein induces apoptosis in HL-60 cells via a ROS-independent mitochondrial death pathway.

Cytotoxic activity of steroidal glycosides from solanum plants

Since some Solanum-genera plants have traditionally been used as anti-cancer and anti-herpes agents from olden times, we examined the cytotoxic activity of typical steroidal glycosides with the framework of spirostane, furostane, spirosolane, and pregnane obtained from Solanum plants. Among these steroidal glycosides, the spirostanol glycosides having a beta-lycotetraosyl moiety were the most effective against PC-12 and HCT-116 cell lines. The potency of activity was observed to be decreased in the order of spirostane, furostane, spirosolane, and pregnane type steroid glycosides. It was also suggested that the activity depend on the kind of oligosaccharide moiety and aglycone moiety.

The hepatoprotective effects of Limonium sinense against carbon tetrachloride and beta-D-galactosamine intoxication in rats

In the present study, the hepatoprotective action of Limonium sinense (Plumbaginaceae) was evident after carbon tetrachloride (CCl(4)) and beta-D-galactosamine (D-GalN), respectively, challenge in rats. The plant materials were divided into two parts: (1) the roots extracted with water (WRE) and (2) the leaves extracted with methanol and fractionated with chloroform (CLE). Both WRE and CLE were extremely flavonoid-enriched extracts. In an CCl(4)-induced acute liver damage study, pretreatment with WRE at 300 mg/kg i.p. and CLE at 100 mg/kg i.p. significantly reduced the amino-transaminases levels of SGOT (p < 0.01) and SGPT (p < 0.01) previously increased by CCl(4) intoxication. In D-GalN-induced acute liver damage study, administration of WRE (300 and 500 mg/kg) or CLE (100 mg/kg) p.o. also significantly reduced the SGOT (p < 0.01) and SGPT (p < 0.01) levels previously increased by D-GalN intoxication. Furthermore, the serum triglyceride level was increased after pretreatment with WRE or CLE previously reduced by D-GalN intoxication. All of the liver function profiles were confirmed to have improvement of liver lesion in histopathological observation. In an acute toxicity test on ICR mice, the LD(50) of WRE was 777.6 mg/kg i.p. An in vitro study showed that CLE possessed a more potent cytotoxicity to human hepatocellular carcinoma cells (Hep3B) (EC(50) = 43.1 micro g/mL) than the other organic fractions, which were fractionated from methanol extracts of the leaves of L. sinense. The present results conclude that L. sinense possesses a hepatoprotective efficacy, and is relatively safe in rats.

Effect of Solanum nudum extracts on the liver of mice infected with Plasmodium berghei

The plant Solanum nudum has been used by the community of Tumaco (Nariño, Colombia) as a cure for malaria. Our group has confirmed the in vitro antimalarial activity against the strain of Plasmodium falciparum FCB-2. During our in vivo studies on the therapeutic effect of Solanum nudum extracts on mice infected with Plasmodium berghei, we observed yellowish tint in the palms of mice treated with the aqueous extract via i.p. at a concentration of 2.4% w/vol. This finding suggested the need to carry out a histology study of the liver. Plasmodium berghei infection produces liver changes such as the deposit of pigment in sinusoids, leucocytes infiltration, esteatosis and necrosis of hepatocytes. These changes were also observed when the mice were treated with methane and hexane extracts from Solanum nudum; however necrosis of hepatocytes in mice infected with malaria decreased 47-65% when they were administered either with aqueous extract, or tumacoside A and degraded diosgenone, compounds from methane and hexane extracts of Solanum nudum respectively.

Treatment with the pure antiestrogen faslodex (ICI 182780) induces tumor necrosis factor receptor 1 (TNFR1) expression in MCF-7 breast cancer cells

Apoptosis induction by the pure antiestrogen faslodex, also known as ICI 182780 (ICI), is associated with an effective down-regulation of Bcl-2 expression in the human breast cancer cell line MCF-7. Recent observations point out that beside members of the Bcl-2 family also the TNFR1 signaling pathway may be involved in apoptosis induction by antiestrogens. In this report we have analyzed the expression of members of the TNFR1 signaling pathway during the apoptotic process induced by the pure antiestrogen faslodex and by tamoxifen (Tam) in MCF-7 breast cancer cells. Treatment with 10(-7) M ICI or 10(-7) M Tam leads to a time dependent increase of TNFR1 and TRADD steady-state mRNA levels in MCF-7 cells. In contrast, Bcl-2 expression was strongly decreased following administration of ICI but only weakly after administration of Tam. Western blot analysis and studies by the use of fluorescence microscopy and flow cytometry revealed a time dependent induction of TNFR1 protein and cell surface expression in MCF-7 cells in response to treatment with ICI. To investigate if TNFR1 is functionally involved in apoptosis induction by antiestrogens, we tested whether TNFR1 blocking antibodies can counteract the growth inhibitory action of Tam and ICI. Coincubation of MCF-7 cells with antiestrogens (ICI or Tam) and blocking TNFR1 antibodies lead to an increase in cell viability. Our results provide evidence for a cross talk between the TNFR1 signaling pathway and antiestrogens during the process of apoptosis induction in MCF-7 breast cancer cells. The superiority of the pure antiestrogen ICI to induce apoptosis in MCF-7 cells may result from its capability to modulate the induction of apoptosis via Bcl-2 as well as TNF-associated signal transduction pathways.

Expression of transposon LINE-1 is relatively human-specific and function of the transcripts may be proliferation-essential

A new 1.7-kb LINE (L1) transcript has been discovered from the cDNA library of human small-cell lung cancer. The nucleotide sequence of 1.7-kb L1 transcript is 98.4% similar to that of open reading frame 2 (ORF2) found in consensus complete 6.5-kb L1. Although L1 DNA segments could be detected from both genomic DNAs of human and rodent cells by PCR, these L1 transcripts were not detectable from cellular RNA of rodent cells by RT-PCR and northern hybridization, implying that the expression of L1 was relatively human-specific. The functions of L1 transcripts in cells are not yet clear. This paper shows that L1 transcripts are essential for cell proliferation when determined by antisense oligonucleotides. Alternately, L1 transcripts exhibit in all human cells we have examined so far, and they map to all the human chromosomes. A sequence-similarity search in the GenBank database indicates that the major sequence of 1.7-kb L1 is integrated in human retinoblastoma (Rb), IL-2, and factor VIII genes. Since Rb and factor VIII genes have displayed high frequency of chromosomal deletions in various cancers and haemophilia A, the universal integration of long and homologous L1 segments in the genes and all chromosomes may be liable to promote abnormal DNA rearrangement.

The rhamnose moiety of solamargine plays a crucial role in triggering cell death by apoptosis

Solamargine, solasodine and khasianine steroidal alkaloids are utilized to determine the role of carbohydrate moiety in the mechanism of apoptosis. The C3 side chain of solamargine, khasianine and solasodine contains 4'Rha-Glc-Rha2', 4'Rha-Glc and H, respectively. Solamargine possessed potent cytotoxicity to human hepatoma cells, while the cytotoxicity of khasianine was greatly diminished. Nevertheless, only solamargine could induced "sub-G1" of apoptotic feature in flowcytometry. Thus, the 2'Rha moiety of solamargine may play a crucial role in triggering cell death by apoptosis. In addition, the molecular modeling of solamargine indicated that the 2'Rha moiety was adjacent to the rigid steroid structure, and drastically changed the dihedral angle of the glycosidic bond. The regulations of TNFR I and II expression by different carbohydrate moieties were also distinct. It implied that the carbohydrate moieties of steroidal alkaloids might alter the binding specificity to steroid receptors and consequently regulate the gene expression in different manners.