Chemopreventive effect of PSP through targeting of prostate cancer stem cell-like population

Polysaccharide-Peptide from Trametes versicolor: The Potential Medicine for Colorectal Cancer Treatment

The incidence and mortality of colorectal cancer have shown an upward trend in the past decade. Therefore, the prevention, diagnosis, and treatment of colorectal cancer still need our continuous attention. Finding compounds with strong anticancer activity and low toxicity is a good strategy for colorectal cancer (CRC) therapy. Trametes versicolor is a traditional Chinese medicinal mushroom with a long history of being used to regulate immunity and prevent cancer. Its extractions were demonstrated with strong cell growth inhibitory activity on human colorectal tumor cells, while the anticancer activity of them is not acted through a direct cytotoxic effect. However, the intricacy and high molecular weight make mechanistic research difficult, which restricts their further application as a medication in clinical cancer treatment. Recent research has discovered a small molecule polysaccharide peptide derived from Trametes versicolor that has a distinct structure after decades of Trametes versicolor investigation. Uncertain molecular weight and a complex composition are problems that have been solved through studies on its structure, and it was demonstrated to have strong anti-proliferation activity on colorectal cancer in vitro and in vivo via interaction with EGFR signaling pathway. It opens up new horizons for research in this field, and these low molecular weight polysaccharide peptides provide a new insight of regulation of colorectal cancer proliferation and have great potential as drugs in the treatment of colorectal cancer.

Microbial polysaccharides: An emerging family of natural biomaterials for cancer therapy and diagnostics

Microbial polysaccharides (MPs) offer immense diversity in structural and functional properties. They are extensively used in advance biomedical science owing to their superior biodegradability, hemocompatibility, and capability to imitate the natural extracellular matrix microenvironment. Ease in tailoring, inherent bio-activity, distinct mucoadhesiveness, ability to absorb hydrophobic drugs, and plentiful availability of MPs make them prolific green biomaterials to overcome the significant constraints of cancer chemotherapeutics. Many studies have demonstrated their application to obstruct tumor development and extend survival through immune activation, apoptosis induction, and cell cycle arrest by MPs. Synoptic investigations of MPs are compulsory to decode applied basics in recent inclinations towards cancer regimens. The current review focuses on the anticancer properties of commercially available and newly explored MPs, and outlines their direct and indirect mode of action. The review also highlights cutting-edge MPs-based drug delivery systems to augment the specificity and efficiency of available chemotherapeutics, as well as their emerging role in theranostics.

Promising Anti-cancer Therapeutics From Mushrooms: Current Findings and Future Perceptions

BACKGROUND

Nowadays, medicines derived from natural sources have drawn much attention as potential therapeutic agents in the suppression and treatment of cancer because of their low toxicity and fewer side effects.

OBJECTIVE

The present review aims to assess the currently available knowledge on the ethnomedicinal uses and pharmacological activities of bioactive compounds obtained from medicinal mushrooms towards cancer treatment.

METHODS

A literature search has been conducted for the collection of research papers from universally accepted scientific databases. These research papers and published book chapters were scrutinized to retrieve information on ethnomedicinal uses of mushrooms, different factors involved in cancer cell proliferation, clinical and in silico pharmaceutical studies made for possible treatments of cancer using mushroom derived compounds. Overall, 241 articles were retrieved and reviewed from the year 1970 to 2020, out of which 98 relevant articles were finally considered for the preparation of this review.

RESULTS

This review presents an update on the natural bioactive substances derived from medicinal mushrooms and their role in inhibiting the factors responsible for cancer cell proliferation. Along with it, the present review also provides information on the ethnomedicinal uses, solvents used for extraction of anti-cancer metabolites, clinical trials, and in silico studies that were undertaken towards anticancer drug development from medicinal mushrooms.

CONCLUSION

The present review provides extensive knowledge on various anti-cancer substances obtained from medicinal mushrooms, their biological actions, and in silico drug designing approaches, which could form a basis for the development of natural anti-cancer therapeutics.

Trametes versicolor (Synn. Coriolus versicolor) Polysaccharides in Cancer Therapy: Targets and Efficacy

Coriolus versicolor (L.) Quél. is a higher fungi or mushroom which is now known by its accepted scientific name as Trametes versicolor (L.) Lloyd (family Polyporaceae). The polysaccharides, primarily two commercial products from China and Japan as PSP and PSK, respectively, have been claimed to serve as adjuvant therapy for cancer. In this paper, research advances in this field, including direct cytotoxicity in cancer cells and immunostimulatory effects, are scrutinised at three levels: in vitro, in vivo and clinical outcomes. The level of activity in the various cancers, key targets (both in cancer and immune cells) and pharmacological efficacies are discussed.

Purification, characterization, and antitumor activity of a novel glucan from the fruiting bodies of Coriolus Versicolor

Cancer is one of the most common causes of deaths worldwide. Herein, we report an efficient natural anticancer glucan (CVG) extracted from Coriolus Versicolar (CV). CVG was extracted by the hot water extraction method followed by ethanol precipitation and purified using gas exclusion chromatography. Structural analysis revealed that CVG has a linear α-glucan chain composed of only (1→ 6)-α-D-Glcp. The antitumor activity of CVG on Sarcoma-180 cells was investigated in vitro and in vivo. Mice were treated with three doses of CVG (40, 100, 200 mg/kg body weight) for 9 days. Tumor weight, relative spleen, thymus weight, and lymphocyte proliferation were studied. A significant increase (P< 0.01) in relative spleen and thymus weight and a decrease (P< 0.01) in tumor weight at the doses of 100 and 200 mg/kg were observed. The results obtained demonstrate CVG has antitumor activity towards Sarcoma-180 cells by its immunomodulation activity.

Adipocytes promote prostate cancer stem cell self-renewal through amplification of the cholecystokinin autocrine loop

Obesity has long been linked with prostate cancer progression, although the underlying mechanism is still largely unknown. Here, we report that adipocytes promote the enrichment of prostate cancer stem cells (CSCs) through a vicious cycle of autocrine amplification. In the presence of adipocytes, prostate cancer cells actively secrete the peptide hormone cholecystokinin (CCK), which not only stimulates prostate CSC self-renewal, but also induces cathepsin B (CTSB) production of the adipocytes. In return, CTSB facilitates further CCK secretion by the cancer cells. More importantly, inactivation of CCK receptor not only suppresses CTSB secretion by the adipocytes, but also synergizes the inhibitory effect of CTSB inhibitor on adipocyte-promoted prostate CSC self-renewal. In summary, we have uncovered a novel mechanism underlying the mutual interplay between adipocytes and prostate CSCs, which may help explaining the role of adipocytes in prostate cancer progression and provide opportunities for effective intervention.

Kazinol-E is a specific inhibitor of ERK that suppresses the enrichment of a breast cancer stem-like cell population

Growing evidence shows that cancer stem-like cells (CSLCs) contribute to breast cancer recurrence and to its resistance to conventional therapies. The extracellular signal-regulated kinase (ERK) signaling pathway is a major determinant in the control of diverse cellular processes, including the maintenance of CSLCs. In this study, we found that Kazinol-E, an antioxidant flavan from Broussonetia kazinoki, decreased the CSLC population of a breast cancer cell line, MCF7. The CSLC population, characterized by CD44 high/CD24 low expression or by high Aldehyde dehydrogenase 1 activity, was decreased by a concentration of Kazinol-E that did not affect the growth of bulk-cultured MCF7 cells. Kazinol-E did not decrease EGF-induced ERK phosphorylation in CSLCs, but did block the phosphorylation of an ERK substrate, p90RSK2, at Thr359/Ser363. We further demonstrated that EGF-induced ERK activity was blocked by Kazinol-E in a wild-type K-Ras-expressing non-small cell lung cancer cell line H226B. An in vitro kinase assay with purified ERK1 and p90RSK2 as its substrate demonstrated a direct inhibition of ERK activity by Kazinol E. Additionally, a the molecular docking study provided putative binding modes of Kazinol-E into the ATP binding pocket of ERK1 Collectively, these results suggest that Kazinol-E is a direct inhibitor of ERK1, and more studies are warranted to develop this reagent for therapeutic breast CSLC targeting.

Chemopreventive and immunomodulatory effects of Murraya koenigii aqueous extract on 4T1 breast cancer cell-challenged mice

BACKGROUND

The progression of breast cancer is increasing at an alarming rate, particularly in western countries. Meanwhile, the lower incidence in Asian countries could be attributed to the heavy incorporation of green leaves vegetables or spices in their diets. Murraya koenigii (MK) or often times known as curry leaves are common spice used mostly in tropical countries. Anti-inflammatory and chemopreventive effects of MK aqueous extract on 4T1 breast cancer cell-challenged mice were evaluated.

METHODS

Herein, cytotoxic activity of MK was first tested on 4T1 cells in vitroby MTT assay. Then, in vivo chemopreventive study was conducted where mice were fed with extracts prior to and after inducing the tumor (inoculation). Tumor size was monitored post-4T1 inoculation. At the end of experiment, histopathology of tumor sections, T cell immunophenotyping, tumor nitric oxide level, serum cytokine level and qPCR analysis on expression of iNOS, iCAM, NF-kB and c-MYC were performed.

RESULTS

MK reduced the tumors' size and lung metastasis aside from inhibited the viability of 4T1 cells in vitro. Furthermore, it decreased the level of nitric oxide and inflammation-related cytokines and genes, including iNOS, iCAM, NF-kB and c-MYC.

CONCLUSION

The results propose that, MK managed to inhibit the progression of tumor via immunostimulatory effect and inflammatory reaction within the tumor samples. This suggests that MKconsumption could be a savior in the search of new chemopreventive agents.

Berberis libanotica Ehrenb extract shows anti-neoplastic effects on prostate cancer stem/progenitor cells

Cancer stem cells (CSCs), including those of advanced prostate cancer, are a suggested reason for tumor resistance toward conventional tumor therapy. Therefore, new therapeutic agents are urgently needed for targeting CSCs. Despite the minimal understanding of their modes of action, natural products and herbal therapies have been commonly used in the prevention and treatment of many cancers. Berberis libanotica Ehrenb (BLE) is a plant rich in alkaloids which may possess anti-cancer activity and a high potential for eliminating CSCs. We tested the effect of BLE on prostate cancer cells and our data indicated that this extract induced significant reduction in cell viability and inhibited the proliferation of human prostate cancer cell lines (DU145, PC3 and 22Rv1) in a dose- and time-dependent manner. BLE extract induced a perturbation of the cell cycle, leading to a G0-G1 arrest. Furthermore, we noted 50% cell death, characterized by the production of high levels of reactive oxidative species (ROS). Inhibition of cellular migration and invasion was also achieved upon treatment with BLE extract, suggesting a role in inhibiting metastasis. Interestingly, BLE extract had a major effect on CSCs. Cells were grown in a 3D sphere-formation assay to enrich for a population of cancer stem/progenitor cells. Our results showed a significant reduction in sphere formation ability. Three rounds of treatment with BLE extract were sufficient to eradicate the self-renewal ability of highly resistant CSCs. In conclusion, our results suggest a high therapeutic potential of BLE extract in targeting prostate cancer and its CSCs.

Polysaccharopeptide enhanced the anti-cancer effect of gamma-tocotrienol through activation of AMPK

Background

Prostate cancer (PCa) frequently relapses after hormone ablation therapy. Unfortunately, once progressed to the castration resistant stage, the disease is regarded as incurable as prostate cancer cells are highly resistant to conventional chemotherapy.

Method

We recently reported that the two natural compounds polysaccharopeptide (PSP) and Gamma-tocotrienols (γ-T3) possessed potent anti-cancer activities through targeting of CSCs. In the present study, using both prostate cancer cell line and xenograft models, we seek to investigate the therapeutic potential of combining γ-T3 and PSP in the treatment of prostate cancer.

Result

We showed that in the presence of PSP, γ-T3 treatment induce a drastic activation of AMP-activated protein kinase (AMPK). This was accompanied with inactivation of acetyl-CoA carboxylase (ACC), as evidenced by the increased phosphorylation levels at Ser 79. In addition, PSP treatment also sensitized cancer cells toward γ-T3-induced cytotoxicity. Furthermore, we demonstrated for the first time that combination of PSP and γ-T3 treaments significantly reduced the growth of prostate tumor in vivo.

Conclusion

Our results indicate that PSP and γ-T3 treaments may have synergistic anti-cancer effect in vitro and in vivo, which warrants further investigation as a potential combination therapy for the treatment of cancer.

Water extract from Pleurotus pulmonarius with antioxidant activity exerts in vivo chemoprophylaxis and chemosensitization for liver cancer

Chemoprophylaxis and chemosensitization are promising strategies to combat human cancers. Natural antioxidant agents show great promise in cancer therapy, and the use of edible mushrooms against cancer is receiving more interest globally. In this study, the radical scavenging activities including diphenyl-1-picrylhydrazyl, superoxide anion radical, hydroxyl radical, and hydrogen peroxide were compared among hot water extracts from 3 edible mushrooms, among which Pleurotus pulmonarius (Pp) possessed the highest antioxidant potential. Oral administration of Pp 2 wk in advance could markedly inhibit the incidence and size of tumor (Huh7 liver cancer cells) with an inhibition rate of 93.1% in nude mice. No obvious side effect was observed in the Pp-treated mice as indicated by their body weight and histological analysis of major organs. The cancer prevention by Pp treatment might be explained by the inhibition of cancer cell proliferation indicated by reduction of ki-67 staining and the inactivation of phosphoinositide 3-kinase (PI3K)/AKT signaling pathway in the Pp-treated mice. Furthermore, a significant synergistic effect was observed when the mice were treated with a combination of low dose of cisplatin and Pp. Taken together, these results suggest the potential application of Pp as an adjuvant in the chemotherapy of liver cancer.

Strategies of functional food for cancer prevention in human beings

Functional food for prevention of chronic diseases is one of this century's key global challenges. Cancer is not only the first or second leading cause of death in China and other countries across the world, but also has diet as one of the most important modifiable risk factors. Major dietary factors now known to promote cancer development are polished grain foods and low intake of fresh vegetables, with general importance for an unhealthy lifestyle and obesity. The strategies of cancer prevention in human being are increased consumption of functional foods like whole grains (brown rice, barley, and buckwheat) and by-products, as well some vegetables (bitter melon, garlic, onions, broccoli, and cabbage) and mushrooms (boletes and Tricholoma matsutake). In addition some beverages (green tea and coffee) may be protective. Southwest China (especially Yunnan Province) is a geographical area where functional crop production is closely related to the origins of human evolution with implications for anticancer influence.

[Pharmaco and diet based prostate cancer prevention]

In 2010, in France, 8,790 men died from prostate cancer despite a low and decreasing mortality rate. The individual risk/benefit ratio of prostate cancer screening is the focus of controversy and currently not in favor of a systematic screening program. Therefore, only prevention could reduce incidence, side effects of treatment and related mortality. Interestingly, prostate cancer prevention is also a field of controversy mainly about 5-alpha-reductase inhibitors. However, it could be expected that pharmaco- or diet-based prevention will be a huge tool for cancer control, even more for prostate cancer burden. This review comprehensively analyses which molecules or compounds could be used in preventive trials. With regard to pharmaco-prevention, three different kinds of drugs could be identified. First drugs, which aim at mainly or even solely reduce prostate cancer risk such as 5-alpha-reductase inhibitors and selective estrogen receptor modulators. Drugs, which aim at wider preventive impact such as: nonsteroidal anti-inflammatory drugs or difluoromethylornithine. Lastly, drugs for which reducing prostate cancer incidence is merely a side effect such as statins, metformin or histones desacetylase inhibitors. With regard to diet-based prevention, two main approaches could be identified: aliments and nutriments, on one hand, and vitamin and minerals, on the other. Interestingly if compounds reach experimental plausibility, natural foods or even global diet seem to have a higher impact. Lastly, besides assessment of efficacy, effectiveness required the critical step of compliance, which might actually be the weakest link of the prevention chain.

Anticancer activity of Amauroderma rude

More and more medicinal mushrooms have been widely used as a miraculous herb for health promotion, especially by cancer patients. Here we report screening thirteen mushrooms for anti-cancer cell activities in eleven different cell lines. Of the herbal products tested, we found that the extract of Amauroderma rude exerted the highest activity in killing most of these cancer cell lines. Amauroderma rude is a fungus belonging to the Ganodermataceae family. The Amauroderma genus contains approximately 30 species widespread throughout the tropical areas. Since the biological function of Amauroderma rude is unknown, we examined its anti-cancer effect on breast carcinoma cell lines. We compared the anti-cancer activity of Amauroderma rude and Ganoderma lucidum, the most well-known medicinal mushrooms with anti-cancer activity and found that Amauroderma rude had significantly higher activity in killing cancer cells than Ganoderma lucidum. We then examined the effect of Amauroderma rude on breast cancer cells and found that at low concentrations, Amauroderma rude could inhibit cancer cell survival and induce apoptosis. Treated cancer cells also formed fewer and smaller colonies than the untreated cells. When nude mice bearing tumors were injected with Amauroderma rude extract, the tumors grew at a slower rate than the control. Examination of these tumors revealed extensive cell death, decreased proliferation rate as stained by Ki67, and increased apoptosis as stained by TUNEL. Suppression of c-myc expression appeared to be associated with these effects. Taken together, Amauroderma rude represented a powerful medicinal mushroom with anti-cancer activities.

Regulation of cell cycle transition and induction of apoptosis in HL-60 leukemia cells by the combination of Coriolus versicolor and Ganoderma lucidum

Medicinal mushrooms have served as the mainstay of treatment for a variety of human illnesses in Asian countries, mostly as supplements by cancer patients. Extracts prepared from Trametes versicolor under the trade name of I'm-Yunity exhibit anti-tumorigenic activities, as supported by inhibition of the proliferation and induction of apoptosis in malignant cells. Similar effects have also been observed for the Reishi mushroom Ganoderma lucidum. The two mushrooms exert their medicinal activities primarily through a family of polysaccharo-peptides. Despite the common identity in their bioactive ingredients, whether their combination might elicit an expanded efficacy and mechanism has not been investigated. In the present study, we investigated similarities and differences between extracts prepared from I'm-Yunity and from a formulation denoted I'm-Yunity-Too combining I'm-Yunity and Ganoderma lucidum. By assaying their anti-proliferative and anti-apoptotic effects using human promyelocytic HL-60 cells, we found that the ethanolic extract of I'm-Yunity-Too was more active in inducing cell death compared to I'm-Yunity, based on measured changes in the expression of caspase 3 and Bax. Moreover, ethanolic extracts of I'm-Yunity-Too exhibited more potent activity compared to its aqueous extracts with regard to suppression of the growth and induction of apoptosis, as assayed by the more pronounced downregulation of phosphorylation of Rb and increased cleavage of poly(ADP‑ribose) polymerase (PARP) from its native 112-kDa form to the inactive 89-kDa product. These results suggested that the chemopreventive potential of I'm-Yunity may be enhanced by adding Ganoderma lucidum and that their bioactive ingre-dients potentially exhibit mechanistic synergism suggesting a more efficacious adjunct in chemotherapy.

In Vivo Immunomodulation and Lipid Peroxidation Activities Contributed to Chemoprevention Effects of Fermented Mung Bean against Breast Cancer

Mung bean has been reported to have antioxidant, cytotoxic, and immunomodulatory effects in vitro. Fermented products are reported to have enhanced immunomodulation and cancer chemopreventive effects. In this study, fermented mung bean treatments in vivo were studied by monitoring tumor development, spleen immunity, serum cytokine (interleukin 2 and interferon gamma) levels, and spleen/tumor antioxidant levels after injection with low and high risk 4T1 breast cancer cells. Pretreatment with fermented mung bean was associated with delayed tumor formation in low risk mice. Furthermore, this treatment was connected with higher serum anticancer cytokine levels, spleen T cell populations, splenocyte cytotoxicity, and spleen/tumor antioxidant levels. Histopathological evaluation of fermented mung bean treated tumor revealed lower event of mitotic division. On the other hand, antioxidant and nitric oxide levels that were significantly increased in the untreated mice were inhibited in the fermented mung bean treated groups. These results suggested that fermented mung bean has potential cancer chemoprevention effects through the stimulation of immunity, lipid peroxidation, and anti-inflammation.

Alpha-tomatine attenuation of in vivo growth of subcutaneous and orthotopic xenograft tumors of human prostate carcinoma PC-3 cells is accompanied by inactivation of nuclear factor-kappa B signaling

Background

Nuclear factor-kappa B (NF-κB) plays a role in prostate cancer and agents that suppress its activation may inhibit development or progression of this malignancy. Alpha (α)-tomatine is the major saponin present in tomato (Lycopersicon esculentum) and we have previously reported that it suppresses tumor necrosis factor-alpha (TNF-α)-induced nuclear translocation of nuclear factor-kappa B (NF-κB) in androgen-independent prostate cancer PC-3 cells and also potently induces apoptosis of these cells. However, the precise mechanism by which α-tomatine suppresses NF-κB nuclear translocation is yet to be elucidated and the anti-tumor activity of this agent in vivo has not been examined.

Methodology/ Principal Findings

In the present study we show that suppression of NF-κB activation by α-tomatine occurs through inhibition of I kappa B alpha (IκBα) kinase activity, leading to sequential suppression of IκBα phosphorylation, IκBα degradation, NF-κB/p65 phosphorylation, and NF-κB p50/p65 nuclear translocation. Consistent with its ability to induce apoptosis, α-tomatine reduced TNF-α induced activation of the pro-survival mediator Akt and its inhibition of NF-κB activation was accompanied by significant reduction in the expression of NF-κB-dependent anti-apoptotic (c-IAP1, c-IAP2, Bcl-2, Bcl-xL, XIAP and survivin) proteins. We also evaluated the antitumor activity of α-tomatine against PC-3 cell tumors grown subcutaneously and orthotopically in mice. Our data indicate that intraperitoneal administration of α-tomatine significantly attenuates the growth of PC-3 cell tumors grown at both sites. Analysis of tumor material indicates that the tumor suppressing effects of α-tomatine were accompanied by increased apoptosis and lower proliferation of tumor cells as well as reduced nuclear translocation of the p50 and p65 components of NF-κB.

Conclusion/ Significance

Our study provides first evidence for in vivo antitumor efficacy of α-tomatine against the human androgen-independent prostate cancer. The potential usefulness of α-tomatine in prostate cancer prevention and therapy requires further investigation.

Transcriptome and proteome exploration to provide a resource for the study of Agrocybe aegerita

BACKGROUND

Agrocybe aegerita, the black poplar mushroom, has been highly valued as a functional food for its medicinal and nutritional benefits. Several bioactive extracts from A. aegerita have been found to exhibit antitumor and antioxidant activities. However, limited genetic resources for A. aegerita have hindered exploration of this species.

METHODOLOGY/PRINCIPAL FINDINGS

To facilitate the research on A. aegerita, we established a deep survey of the transcriptome and proteome of this mushroom. We applied high-throughput sequencing technology (Illumina) to sequence A. aegerita transcriptomes from mycelium and fruiting body. The raw clean reads were de novo assembled into a total of 36,134 expressed sequences tags (ESTs) with an average length of 663 bp. These ESTs were annotated and classified according to Gene Ontology (GO), Clusters of Orthologous Groups (COG), and Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathways. Gene expression profile analysis showed that 18,474 ESTs were differentially expressed, with 10,131 up-regulated in mycelium and 8,343 up-regulated in fruiting body. Putative genes involved in polysaccharide and steroid biosynthesis were identified from A. aegerita transcriptome, and these genes were differentially expressed at the two stages of A. aegerita. Based on one-dimensional gel electrophoresis (1-DGE) coupled with electrospray ionization liquid chromatography tandem MS (LC-ESI-MS/MS), we identified a total of 309 non-redundant proteins. And many metabolic enzymes involved in glycolysis were identified in the protein database.

CONCLUSIONS/SIGNIFICANCE

This is the first study on transcriptome and proteome analyses of A. aegerita. The data in this study serve as a resource of A. aegerita transcripts and proteins, and offer clues to the applications of this mushroom in nutrition, pharmacy and industry.

Anticancer polysaccharides from natural resources: a review of recent research

Taking into account the rising trend of the incidence of cancers of various organs, effective therapies are urgently needed to control human malignancies. However, almost all of the chemotherapy drugs currently on the market cause serious side effects. Fortunately, several previous studies have shown that some non-toxic biological macromolecules, including polysaccharides and polysaccharide-protein complexes, possess anti-cancer activities or can increase the efficacy of conventional chemotherapy drugs. Based on these encouraging observations, a great deal of effort has been focused on discovering anti-cancer polysaccharides and complexes for the development of effective therapeutics for various human cancers. This review focuses on the advancements in the anti-cancer efficacy of various natural polysaccharides and polysaccharide complexes in the past 5 years. Most polysaccharides were tested using model systems, while several involved clinical trials.

A new prospect in cancer therapy: targeting cancer stem cells to eradicate cancer

According to the cancer stem cell theory, cancers can be initiated by cancer stem cells. This makes cancer stem cells prime targets for therapeutic intervention. Eradicating cancer stem cells by efficient targeting agents may have the potential to cure cancer. In this review, we summarize recent breakthroughs that have improved our understanding of cancer stem cells, and we discuss the therapeutic strategy of targeting cancer stem cells, a promising future direction for cancer stem cell research.

Genistein inhibits the stemness properties of prostate cancer cells through targeting Hedgehog-Gli1 pathway

Cancer stem cells (CSCs) are involved in tumorigenesis and progression of prostate cancer (PCa). Conventional anticancer therapeutics failed to eradicate CSCs, which may eventually lead to the disease relapse and metastasis. Therefore, targeting prostate CSCs may be an ideal strategy to cure PCa. Genistein is a major isoflavone constituent of soybeans and soy products, which has been shown to exhibit potent anticancer effect on many cancers. We have previously reported that genistein can inhibit PCa cell invasion by reversing epithelial to mesenchymal transition, suggesting that genistein may be effective against metastatic PCa. In addition, we have recently demonstrated that PCa tumorsphere cells (TCs) possess CSC properties. Here, we found that tumorsphere formation and colony formation of Pca cells were noticeably suppressed in the presence of genistein. Pretreatment of PCa TCs with genistein also suppressed tumorigenicity in vivo. Additionally, genistein treatment inhibited tumor growth of PCa TCs. Further studies showed that genistein treatment not only led to the down-regulation of PCa CSC markers CD44 in vitro and in vivo, but also inhibited Hedgehog-Gli1 pathway, which may contribute to the anti-CSC effect of genistein in PCa TCs. Therefore, our findings demonstrated that genistein may be a dietary phytochemical with potential to target prostate CSCs.

Protective effects of white button mushroom (Agaricus bisporus) against hepatic steatosis in ovariectomized mice as a model of postmenopausal women

Nonalcoholic fatty liver disease (NAFLD) includes various hepatic pathologies ranging from hepatic steatosis to non-alcoholic steatohepatitis (NASH), fibrosis and cirrhosis. Estrogen provides a protective effect on the development of NAFLD in women. Therefore, postmenopausal women have a higher risk of developing NAFLD. Hepatic steatosis is an early stage of fatty liver disease. Steatosis can develop to the aggressive stages (nonalcoholic steatohepatitis, fibrosis and cirrhosis). Currently, there is no specific drug to prevent/treat these liver diseases. In this study, we found that white button mushroom (WBM), Agaricus Bisporus, has protective effects against liver steatosis in ovariectomized (OVX) mice (a model of postmenopausal women). OVX mice were fed a high fat diet supplemented with WBM powder. We found that dietary WBM intake significantly lowered liver weight and hepatic injury markers in OVX mice. Pathological examination of liver tissue showed less fat accumulation in the livers of mice on WBM diet; moreover, these animals had improved glucose clearance ability. Microarray analysis revealed that genes related to the fatty acid biosynthesis pathway, particularly the genes for fatty acid synthetase (Fas) and fatty acid elongase 6 (Elovl6), were down-regulated in the liver of mushroom-fed mice. In vitro mechanistic studies using the HepG2 cell line showed that down-regulation of the expression of FAS and ELOVL6 by WBM extract was through inhibition of Liver X receptor (LXR) signaling and its downstream transcriptional factor SREBP1c. These results suggest that WBM is protective against hepatic steatosis and NAFLD in OVX mice as a model for postmenopausal women.