Mechanism of synergistic inhibitory effect of benzyl isothiocyanate and zoledronic acid combination on breast cancer induction of osteoclast differentiation.

Bone is the most favored site for metastasis for each major subtype of breast cancer. Therapeutic modalities for alleviation of clinical symptoms associated with bone metastasis include surgical resection, radiation, and bone-targeted therapies, including bisphosphonates (e.g., zoledronic acid; ZA) and a humanized antibody against receptor activator of nuclear factor-κB ligand (denosumab). However, the bone-targeted therapies are expensive, and have poor pharmacokinetic attributes and/or serious adverse effects. Therefore, novel strategies are needed for treatment of bone metastasis or to increase effectiveness of existing bone-targeted therapies. We have shown previously that benzyl isothiocyanate (BITC) is a novel inhibitor of osteoclast differentiation in vitro and bone metastasis in vivo. The present study shows that BITC + ZA combination synergistically inhibits osteoclast differentiation induced by addition of conditioned media from breast cancer cells. These effects were associated with a significant increase in levels of several antiosteoclastogenic cytokines, including interferons, interleukin (IL)-3, IL-4, and IL-27. Kyoto Encyclopedia of Genes and Genomes pathway analysis of RNA-seq data from BITC and/or ZA-treated cells revealed downregulation of genes of many pathways (e.g., actin cytoskeleton, Hippo signaling, etc.) by treatment with BITC + ZA combination, but not by BITC alone or ZA alone. Confocal microscopy confirmed severe disruption of actin cytoskeleton upon treatment of MCF-7 and MDA-MB-231 cells with the BITC + ZA combination. This combination also decreased the nuclear level of yes-associated protein, a core component of Hippo signaling. In conclusion, the present study offers a novel combination for prevention or treatment of bone metastasis of breast cancer.

Forkhead Box Q1 is a novel regulator of autophagy in breast cancer cells.

Forkhead Box Q1 (FoxQ1) transcription factor is overexpressed in luminal-type and basal-type human breast cancers when compared to normal mammary tissue. This transcription factor is best known for its role in promotion of breast cancer stem-like cells and epithelial to mesenchymal transition. The present study documents a novel function of FoxQ1 in breast cancer cells. Overexpression of FoxQ1 in basal-like SUM159 cells and luminal-type MCF-7 cells resulted in increased conversion of microtubule-associated protein light chain 3 beta-I (LC3B-I) to LC3B-II, which is a hallmark of autophagy. Autophagy induction by FoxQ1 overexpression was confirmed by visualization of LC3B puncta as well as by transmission electron microscopy. Expression profiling for genes implicated in autophagy regulation revealed upregulation of many genes, including ATG4B, ATG16L1, CTSS, CXCR4 and so forth but downregulation of BCL2L1, DRAM1, TNF, ULK2 and so forth by FoxQ1 overexpression in SUM159 cells. Western blot analysis confirmed upregulation of ATG4B and CXCR4 proteins by FoxQ1 overexpression in both SUM159 and MCF-7 cells. Chromatin immunoprecipitation assay revealed recruitment of FoxQ1 at the promoter of ATG4B. Pharmacological inhibition of ATG4B using S130 significantly increased apoptosis induction by DOX in empty vector transfected as well as FoxQ1 overexpressing SUM159 and MCF-7 cells but this effect was statistically significantly lowered by FoxQ1 overexpression indicating the protective role of FoxQ1 on apoptosis. Treatment of SUM159 cells with S130 and DOX enhanced LC3B-II level in both empty vector transfected cells and FoxQ1 overexpressing SUM159 cells but not in FoxQ1 overexpressing MCF-7 cells. In conclusion, FoxQ1 is a novel regulator of autophagy.

Withaferin A inhibits breast cancer-induced osteoclast differentiation.

Bone is the most prone to metastatic spread of breast cancer cells for each subtype of the disease. Bone metastasis-related complications including severe pain and pathological fractures affect patients' quality of life. Current treatment options including surgery, radiation, and bone-targeted therapies (e.g., bisphosphonates) are costly or have serious adverse effects such as renal toxicity and osteonecrosis of the jaws. Therefore, a safe, inexpensive, and efficacious agent for prevention of breast cancer bone metastasis is urgently needed. Our previously published RNA sequencing analysis revealed that many genes implicated in bone remodeling and breast cancer bone metastasis were significantly downregulated by treatment with withaferin A (WA), which is a promising cancer chemopreventive agent derived from a medicinal plant (Withania somnifera). The present study investigated whether WA inhibits breast cancer induction of osteoclast differentiation. At plasma achievable doses, WA treatment inhibited osteoclast differentiation (osteoclastogenesis) induced by three different subtypes of breast cancer cells (MCF-7, SK-BR-3, and MDA-MB-231). WA and the root extract of W. somnifera were equally effective for inhibition of breast cancer induction of osteoclast differentiation. This inhibition was accompanied by suppression of interleukin (IL)-6, IL-8, and receptor activator of nuclear factor-κB ligand, which are pivotal osteoclastogenic cytokines. The expression of runt-related transcription factor 2, nuclear factor-κB, and SOX9 transcription factors, which positively regulate osteoclastogenesis, was decreased in WA-treated breast cancer cells as revealed by confocal microscopy and/or immunoblotting. Taken together, these data suggest that WA could be a promising agent for prevention of breast cancer-induced bone metastasis.

Withaferin A Inhibits Fatty Acid Synthesis in Rat Mammary Tumors.

Withaferin A (WA), which is a small molecule derived from a medicinal plant (Withania somnifera), inhibits growth of human breast cancer xenografts and mammary tumor development in rodent models without any toxicity. However, the mechanism underlying inhibition of mammary cancer development by WA administration is not fully understood. Herein, we demonstrate that the fatty acid synthesis pathway is a novel target of WA in mammary tumors. Treatment of MCF-7 and MDA-MB-231 cells with WA resulted in suppression of fatty acid metabolizing enzymes, including ATP-citrate lyase (ACLY), acetyl-CoA carboxylase 1 (ACC1), fatty acid synthase (FASN), and carnitine palmitoyltransferase 1A (CPT1A). Expression of FASN and CPT1A was significantly higher in N-methyl-N-nitrosourea-induced mammary tumors in rats when compared with normal mammary tissues. WA-mediated inhibition of mammary tumor development in rats was associated with a statistically significant decrease in expression of ACC1 and FASN and suppression of plasma and/or mammary tumor levels of total free fatty acids and phospholipids. WA administration also resulted in a significant increase in percentage of natural killer cells in the spleen. The protein level of sterol regulatory element binding protein 1 (SREBP1) was decreased in MDA-MB-231 cells after WA treatment. Overexpression of SREBP1 in MDA-MB-231 cells conferred partial but significant protection against WA-mediated downregulation of ACLY and ACC1. In conclusion, circulating and/or mammary tumor levels of fatty acid synthesis enzymes and total free fatty acids may serve as biomarkers of WA efficacy in future clinical trials. PREVENTION RELEVANCE: The present study shows that breast cancer prevention by WA in rats is associated with suppression of fatty acid synthesis.

Breast Cancer Selective Disruption of Actin Cytoskeleton by Diallyl Trisulfide.

Diallyl trisulfide (DATS) is an attractive anti-cancer phytochemical with in vitro and in vivo growth inhibitory effects against different solid tumors including breast cancer. We have shown previously that an immortalized mammary epithelial cell line (MCF-10A) is resistant to growth inhibition by DATS. In this study, we performed RNA-seq analysis using a breast cancer cell line (SK-BR-3) and MCF-10A cells to gain insights into cancer selective effects of DATS. The Gene Ontology analysis revealed upregulation of genes associated with actin cytoskeleton but downregulation of mitochondria-related genes in the SK-BR-3 human breast cancer cell line but not in the non-oncogenic MCF-10A cell line upon treatment with DATS. Quantitative real-time reverse transcription polymerase chain reaction confirmed DATS-mediated upregulation of several actin cytoskeleton-related genes in the SK-BR-3 cell line. The DATS treatment dose-dependently disrupted actin cytoskeleton in the SK-BR-3 cell line, whereas the MCF-10A cell line was more resistant to this effect. The DATS treatment caused a marked increase in phosphorylation of dynamin-1-like (DRP1) protein in the SK-BR-3 cell line. However, the DATS-mediated apoptosis was not affected by genetic deletion of DRP1 protein. The Reactome pathway analysis showed downregulation of genes associated with citric acid cycle in the SK-BR-3 cell line but not in the MCF-10A cells. However, expression of aconitase 2 or dihydrolipoamide S-succinyltransferase was not affected by DATS treatment. In conclusion, this study reveals that actin cytoskeleton is a novel target of DATS in the SK-BR-3 cell line, which may explain its inhibitory effect on breast cancer cell migration.

Gene Expression Changes by Diallyl Trisulfide Administration in Chemically-induced Mammary Tumors in Rats.

Diallyl trisulfide (DATS) was shown to be a potent inhibitor of luminal-type MCF-7 xenograft growth in vivo. The present study was conducted to determine the preventive effect of DATS administration using an N-methyl-N-nitrosourea (MNU)-induced rat mammary tumor model, which shares molecular resemblance to luminal-type human breast cancers. The DATS administration (50 mg/kg body weight, 5 times/week) was safe, but did not reduce mammary tumor latency, incidence, burden or multiplicity. Therefore, we conducted RNA-seq analysis using mammary tumors from control and DATS-treated rats (n = 3 for each group) to gain insights into lack of mammary tumor prevention by this phytochemical. The gene ontology and the Kyoto encyclopedia of genes and genomes pathway analyses of the RNA-seq data revealed upregulation of genes associated with ribosomes, translation, peptide biosynthetic/metabolic process, and oxidative phosphorylation but downregulation of genes associated with mitogen-activated protein kinases. A total of 33 genes associated with ribosomes were significantly upregulated by DATS treatment, including RPL11 and RPS14. Western blotting confirmed upregulation of RPL11 and neurofascin protein expression in mammary tumors from DATS-treated rats when compared to controls. A statistically significant increase in protein level of c-Jun N-terminal kinase 2 was also observed in tumors from DATS-treated rats when compared to controls. On the other hand, expression of complex I subunits NDUFV1 or NDUFS1 was not affected by DATS treatment. These results offer potential explanations for ineffectiveness of DATS in the chemically-induced rat mammary tumor model. Inhibitors of the proteins upregulated by DATS may be needed to improve chemopreventive efficacy of this phytochemical.

Leelamine suppresses cMyc expression in prostate cancer cells in vitro and inhibits prostate carcinogenesis in vivo.

AIM: Leelamine (LLM) inhibits growth of human prostate cancer cells but the underlying mechanism is not fully understood. The present study was undertaken to determine the effect of LLM on cMyc, which is overexpressed in a subset of human prostate cancers. METHODS: The effect of LLM on cMyc expression and activity was determined by western blotting/confocal microscopy and luciferase reporter assay, respectively. A transgenic mouse model of prostate cancer (Hi-Myc) was used to determine chemopreventive efficacy of LLM. RESULTS: Exposure of androgen sensitive (LNCaP) and castration-resistant (22Rv1) human prostate cancer cells to LLM resulted in downregulation of protein and mRNA levels of cMyc. Overexpression of cMyc partially attenuated LLM-mediated inhibition of colony formation, cell viability, and cell migration in 22Rv1 and/or PC-3 cells. LLM treatment decreased protein levels of cMyc targets (e.g., lactate dehydrogenase), however, overexpression of cMyc did not attenuate these effects. A trend for a decrease in expression level of cMyc protein was discernible in 22Rv1 xenografts from LLM-treated mice compared with control mice. The LLM treatment (10 mg/kg body weight, 5 times/week) was well-tolerated by Hi-Myc transgenic mice. The incidence of high-grade prostatic intraepithelial neoplasia, adenocarcinoma in situ, and microinvasion was lower in LLM-treated Hi-Myc mice but the difference was not statistically significant. CONCLUSION: The present study reveals that LLM inhibits cMyc expression in human prostate cancer cells in vitro but concentrations higher than 10 mg/kg may be required to achieve chemoprevention of prostate cancer.

Mechanistic Targets of Diallyl Trisulfide in Human Breast Cancer Cells Identified by RNA-seq Analysis.

Diallyl trisulfide (DATS), a metabolic by-product of processed garlic, is highly effective in inhibiting growth of human breast cancer cells in vitro and in vivo, but the underlying mechanisms are still not fully understood. In this study, we performed RNA-seq analyses using luminal-type (MCF-7) and basal-like (MDA-MB-231) human breast cancer cells to identify mechanistic targets of DATS. The Reactome Pathway Analysis revealed upregulation of genes associated with SLIT/ROBO tumor suppressor signaling following DATS treatment in both MCF-7 and MDA-MB-231 cells. However, the expression of SLIT2 and ROBO1 proteins or their downstream target C-X-C motif chemokine receptor 4 was not affected by DATS treatment in both cell lines. The Reactome as well as the Gene Ontology Pathways Analyses of the RNA-seq data from DATS-treated cells indicated downregulation of genes associated with G2/M phase cell cycle arrest in comparison with vehicle-treated control cells. Consistent with the RNA-seq data, DATS treatment caused a significant increase in the fraction of the G2/M population in both cell lines when compared to corresponding control cells. In addition, Ser10 phosphorylation of histone H3, a mitotic marker, was also increased significantly following DATS treatment in MCF-7 and MDA-MB-231 cells. These results indicate that while SLIT/ROBO signaling is not affected by DATS treatment, cell cycle arrest likely contributes to the antitumor effect of this phytochemical.

The Role of Forkhead Box Q1 Transcription Factor in Anticancer Effects of Withaferin A in Breast Cancer.

Elimination of both rapidly dividing epithelial mammary cancer cells as well as breast cancer stem-like cells (bCSC) is essential for maximizing antitumor response. Withaferin A (WA), a small molecule derived from a medicinal plant (Withania somnifera), is highly effective in reducing burden and/or incidence of breast cancer in vivo in various preclinical models. We have shown previously that suppression of breast cancer incidence by WA administration in a rat model is associated with a decrease in self-renewal of bCSC but the underlying mechanism is still elusive. This study investigated the role of forkhead box Q1 (FoxQ1) transcription factor in antitumor responses to WA. Exposure of MDA-MB-231 and SUM159 cells to WA resulted in downregulation of protein and mRNA levels of FoxQ1 as well as inhibition of its transcriptional activity. FoxQ1 overexpression in SUM159 and MCF-7 cells resulted in a marked protection against WA-mediated inhibition of bCSC as judged by flow cytometric analysis of CD49fhigh population and mammosphere assay. RNA-sequencing analysis revealed upregulation of many bCSC-associated genes by FoxQ1 overexpression in SUM159 cells, including IL8 whose expression was decreased by WA treatment in SUM159 and MCF-7 cells. FoxQ1 was recruited to the promoter of IL8 that was inhibited significantly by WA treatment. On the other hand, WA-mediated inhibition of cell proliferation or migration was not affected by FoxQ1 overexpression. The FoxQ1 overexpression partially attenuated WA-mediated G2-M phase cell cycle arrest in SUM159 cells only. These results indicate that FoxQ1 is a target of WA for inhibition of bCSC fraction. PREVENTION RELEVANCE: Withaferin A (WA) is highly effective in reducing burden and/or incidence of breast cancer in various preclinical models. However, the mechanism underlying breast cancer prevention by WA is not fully understood. This study shows a role for FoxQ1 in antitumor response to WA.

RNA-seq reveals novel cancer-selective and disease subtype-independent mechanistic targets of withaferin A in human breast cancer cells.

Withaferin A (WA) exhibits cancer chemopreventive efficacy in preclinical models representative of two different subtypes of breast cancer. However, the mechanism(s) underlying breast cancer chemoprevention by WA is not fully elucidated. We performed RNA-seq analyses using a non-tumorigenic mammary epithelial cell line (MCF-10A) and human breast cancer cells (BCC) belonging to the luminal-type (MCF-7), HER2-enriched (SK-BR-3), and basal-like subtype (MDA-MB-231) to identify novel cancer-selective mechanistic targets of WA. The WA-regulated transcriptome was strikingly different between MCF-10A versus BCC. The Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed downregulation of genes associated with cellular senescence in WA-treated BCC. Consequently, the number of senescence-associated ß-galactosidase positive cells was decreased significantly in WA-treated BCC but not in the MCF-10A cells. WA treatment caused upregulation of senescence marker p21 more robustly in BCC than in MCF-10A. Breast cancer prevention by WA in rats was also associated with upregulation of p21 protein expression. The Reactome pathway analyses indicated upregulation of genes associated with cellular response to stress/external stimuli in WA-treated BCC but not in MCF-10A. Two proteins represented in these pathways (HSPA6 and NRF2) were further investigated. While HSPA6 was dispensable for WA-mediated apoptosis and autophagy or inhibition of cell migration, the NRF2 knockout cells were more resistant to apoptosis resulting from WA treatment than control cells. Finally, expression of some glycolysis-related proteins was decreased by WA treatment both in vitro and in vivo. In summary, this study provides novel insights into cancer-selective pathways affected by WA that may contribute to its chemopreventive efficacy in breast cancer.

A novel metabolic function of Myc in regulation of fatty acid synthesis in prostate cancer.

A subset of human prostate cancer exhibits increased de novo synthesis of fatty acids, but the molecular driver(s) of this metabolic abnormality remains obscure. This study demonstrates a novel metabolic function of c-Myc (Myc) in regulation of fatty acid synthesis. The role of Myc in regulation of fatty acid synthesis was investigated by: (a) interrogation of the prostate cancer The Cancer Genome Atlas (TCGA) dataset, (b) chromatin immunoprecipitation, and (c) determination of the expression of fatty acid synthesis enzymes and targeted metabolomics using a mouse model and human specimens. The expression of MYC was positively associated with that of key fatty acid synthesis genes including ACLY, ACC1, and FASN in prostate cancer TCGA dataset. Chromatin immunoprecipitation revealed Myc occupancy at the promoters of ACLY, ACC1, and FASN. Prostate-specific overexpression of Myc in Hi-Myc transgenic mice resulted in overexpression of ACLY, ACC1, and FASN proteins in neoplastic lesions and increased circulating levels of total free fatty acids. Targeted metabolomics confirmed increased circulating levels of individual fatty acids in the plasma of Hi-Myc mice and human subjects when compared to corresponding controls. Immunohistochemistry also revealed a positive and statistically significant association in expression of Myc with that of ACC1 in human prostate adenocarcinoma specimens. We propose that Myc-regulated fatty acid synthesis is a valid target for therapy and/or prevention of prostate cancer.

Cytoprotective autophagy induction by withaferin A in prostate cancer cells involves GABARAPL1.

Withaferin A (WA) is a naturally occurring steroidal lactone with proven cancer chemopreventive activity in preclinical models of different cancers including prostate adenocarcinoma. Previously we compared the RNA-seq data from control and WA-treated 22Rv1 human prostate cancer cells to identify mechanistic targets of this phytochemical. The Gene Ontology pathway analysis of the RNA-seq data revealed significant upregulation of genes associated with autophagy upon WA treatment in 22Rv1 cells. In this study, we extended these findings to investigate the mechanism underlying WA-induced autophagy. Initially, we confirmed autophagy induction by WA treatment by transmission electron microscopy using three prostate cancer cell lines (LNCaP, 22Rv1, and PC-3). Fourteen common genes altered by 8- and 16-hour exposure to WA were identified from human autophagy PCR array and these results were consistent with the RNA-seq data. Two key autophagy markers (LC3BII and SQSTM1) were robustly increased in WA-exposed LNCaP, 22Rv1, and PC-3 cells as determined by immunoblotting, and this effect was elevated in the presence of autophagy inhibitor bafilomycin A1 (BafA1). BafA1 treatment augmented WA's cytotoxicity and subsequently its proapoptotic potential. WA treatment induced GABARAPL1 (ATG8L) protein expression in all three cell lines and its knockdown by RNA interference attenuated WA-mediated apoptosis. WA-induced autophagy was not affected in the presence of an antioxidant (EUK134). Taken together, the present study reveals that WA-mediated autophagy is cytoprotective and mediated by GABARAPL1.

Novel mechanistic targets of forkhead box Q1 transcription factor in human breast cancer cells.

The transcription factor forkhead box Q1 (FoxQ1) is overexpressed in different solid tumors including breast cancer, but the mechanism underlying its oncogenic function is still not fully understood. In this study, we compared RNA-seq data from FoxQ1 overexpressing SUM159 cells with that of empty vector-transfected control cells to identify novel mechanistic targets of this transcription factor. Analysis of The Cancer Genome Atlas (TCGA) data set revealed significantly higher expression of FoxQ1 in black breast cancer patients compared with white women with this disease. In contrast, expression of FoxQ1 was comparable in ductal and lobular carcinomas in the breast cancer TCGA data set. Complementing our published findings in basal-like subtype, immunohistochemistry revealed upregulation of FoxQ1 protein in luminal-type human breast cancer tissue microarrays when compared with normal mammary tissues. Many previously reported transcriptional targets of FoxQ1 (eg, E-cadherin, N-cadherin, fibronectin 1, etc) were verified from the RNA-seq analysis. FoxQ1 overexpression resulted in the downregulation of genes associated with cell cycle checkpoints, M phase, and cellular response to stress/external stimuli as evidenced from the Reactome pathway analysis. Consequently, FoxQ1 overexpression resulted in mitotic arrest in basal-like SUM159 and human mammary epithelial cell line, but not in luminal-type MCF-7 cells. Finally, we show for the first time that FoxQ1 is a direct transcriptional regulator of interleukin (IL)-1α, IL-8, and vascular endothelial growth factor in breast cancer cells as evidenced by chromatin immunoprecipitation assay. In conclusion, the present study reports novel mechanistic targets of FoxQ1 in human breast cancer cells.

A Comprehensive Review and Perspective on Anticancer Mechanisms of Withaferin A in Breast Cancer.

Withaferin A (hereafter abbreviated as WA) is a promising anticancer steroidal lactone abundant in a medicinal plant (Withania somnifera) native to Asia. The root/leaf extract of Withania somnifera, which belongs to the Solanaceae family, continues to be included in the Ayurvedic medicine formulations of alternative medicine practice. Numerous chemicals are detectable in the root/leaf extract of Withania somnifera [e.g., withanolides (WA, withanone, withanolide A, etc.), alkaloids, sitoindosides, etc.], but the anticancer effect of this medicinal plant is largely attributed to WA. Anticancer effect of WA was initially reported in the early 70s in the Ehrlich ascites tumor cell model in vitro Since then, numerous preclinical studies have been performed using cellular and animal models of different cancers including breast cancer to determine cancer therapeutic and chemopreventive effects of WA. Chemoprevention, a word first introduced by Dr. Michael B. Sporn, was intended to impede, arrest, or reverse carcinogenesis at its earliest stages with pharmacologic agents. This review succinctly summarizes the published findings on anticancer pharmacology of WA in breast cancer focusing on pharmacokinetic behavior, in vivo efficacy data in preclinical models in a therapeutic and chemoprevention settings, and its known effects on cancer-relevant cellular processes (e.g., growth arrest, apoptosis induction, autophagy, metabolic adaptation, immune function, etc.) and molecular targets (e.g., suppression of oncogenes such as estrogen receptor-α, STAT3, etc.). Potential gaps in knowledge as well as future research directions essential for clinical development of WA for chemoprevention and/or treatment of breast cancer are also discussed.

Withania somnifera root extract inhibits fatty acid synthesis in prostate cancer cells.

Prior research argues for a role of increased de novo fatty acid synthesis in pathogenesis of prostate adenocarcinoma, which remains a leading cause of cancer-associated mortality in American men. A safe and effective inhibitor of fatty acid synthesis is still a clinically unmet need. Herein, we investigated the effect of ethanol extract of Withania somnifera root (WRE) standardized for one of its components (withaferin A) on fatty acid synthesis using LNCaP and 22Rv1 human prostate cancer cells. Withania somnifera is a medicinal plant used in the Ayurvedic medicine practiced in India. Western blotting and confocal microscopy revealed a statistically significant decrease in protein levels of key fatty acid metabolism enzymes including ATP citrate lyase (ACLY), acetyl-CoA carboxylase 1 (ACC1), fatty acid synthase (FASN), and carnitine palmitoyltransferase 1A (CPT1A) in WRE-treated cells compared with solvent control. The mRNA levels of ACLY, ACC1, FASN, and CPT1A were also lower in WRE-treated cells in comparison with control. Consequently, WRE treatment resulted in a significant decrease in intracellular levels of acetyl-CoA, total free fatty acids, and neutral lipid droplets in both LNCaP and 22Rv1 cells. WRE exhibited greater potency for fatty acid synthesis inhibition at equimolar concentration than cerulenin and etomoxir. Exposure to WRE results in downregulation of c-Myc and p-Akt(S473) proteins in 22Rv1 cell line. However, overexpression of only c-Myc conferred protection against clonogenic cell survival and lipogenesis inhibition by WRE. In conclusion, these results indicate that WRE is a novel inhibitor of fatty acid synthesis in human prostate cancer cells.

Prevention of Prostate Cancer in Transgenic Adenocarcinoma of the Mouse Prostate Mice by Yellow Passion Fruit Extract and Antiproliferative Effects of Its Bioactive Compound Piceatannol.

Piceatannol (PIC), a polyphenol presents in many vegetables and fruits including yellow passion fruit extract (PFE; Passiflora edulis), has anti-cancer activity, but its molecular targets are still poorly understood. The aims of this study were to investigate the molecular mechanistic actions of PIC in prostate cancer cell lines and to test if the extract from PFE rich in PIC can affect the growth of prostate cancer cells in the Transgenic Adenocarcinoma of the Mouse Prostate (TRAMP) model. The PC-3, 22Rv1, LNCaP, and VCaP prostate cancer cells were exposed to PIC (10-40 µM), and cell viability, lactate measurement, Western blot, and flow cytometric analyses were performed. For an in vivo experiments, eight-week-old TRAMP mice (n = 10 per group each) received an aqueous extract of PFE containing 20 mg of PIC/kg or water (control group) by gavage for 4 or 10 weeks for further analyses. PIC treatment concentration- and time-dependently reduced viability of all cell lines tested. 22Rv1 and LNCaP cells treated with PIC did not exhibit any significant alteration in the intracellular accumulation of lactate. PIC treatment caused G0/G1 phase cell cycle arrest and induction of apoptosis in both LNCaP and 22Rv1 cells. PIC-treated cells exhibited altered protein levels of p53, p21, cyclin D1, and cyclin-dependent kinase 4 (cdk4). The short and long-term PFE treatments also affected p21, cyclin D1 and cdk4 and delayed disease progression in TRAMP, with a decreased incidence of preneoplastic lesions. In conclusion, PIC apparently does not alter glucose metabolism in prostate cancer cells, while cell cycle arrest and p53 modulation are likely important in anti-cancer effects of PIC alone or as a food matrix byproduct in prostate cancer cells, especially those with an androgen-dependent phenotype.

The Role of Lysosome-associated Membrane Protein 2 in Prostate Cancer Chemopreventive Mechanisms of Sulforaphane.

Prostate cancer chemoprevention by sulforaphane, which is a metabolic by-product of glucoraphanin found in broccoli, in preclinical models is associated with induction of both apoptosis and autophagy. However, the molecular mechanism underlying sulforaphane-mediated autophagy, which is protective against apoptotic cell death by this phytochemical, is still poorly understood. This study demonstrates a role for lysosome-associated membrane protein 2 (LAMP2) in sulforaphane-mediated autophagy and apoptosis. Western blotting revealed dose-dependent induction of LAMP2 protein after treatment with sulforaphane as well as its naturally occurring analogs in PC-3 and 22Rv1 human prostate cancer cell lines that was confirmed by microscopy (sulforaphane). The mRNA level of LAMP2 was also increased upon treatment with sulforaphane in both cell lines. Sulforaphane-mediated increase in the level of autophagy marker microtubule-associated protein light-chain 3B was augmented by RNAi of LAMP2 in PC-3 and 22Rv1 cells. Apoptosis induction by sulforaphane treatment was also increased significantly by knockdown of the LAMP2 protein in PC-3 and 22Rv1 cells. Augmentation of sulforaphane-mediated apoptosis by RNAi of LAMP2 was accompanied by induction and activation of proapoptotic protein Bak. Oral administration of sulforaphane to TRAMP mice also resulted in induction of LAMP2 protein expression. Targeted microarray in sulforaphane-treated PC-3 cells revealed induction of many autophagy-related genes (e.g., HSP90AA1, NRF2, etc) and their expression positively correlated with that of LAMP2 in prostate cancer The Cancer Genome Atlas. In conclusion, this study reveals that induction of LAMP2 by sulforaphane inhibits its ability to induce apoptotic cell death at least in human prostate cancer cells.

Super-resolution imaging reveals the evolution of higher-order chromatin folding in early carcinogenesis.

Genomic DNA is folded into a higher-order structure that regulates transcription and maintains genomic stability. Although progress has been made on understanding biochemical characteristics of epigenetic modifications in cancer, the in-situ higher-order folding of chromatin structure during malignant transformation remains largely unknown. Here, using optimized stochastic optical reconstruction microscopy (STORM) for pathological tissue (PathSTORM), we uncover a gradual decompaction and fragmentation of higher-order chromatin folding throughout all stages of carcinogenesis in multiple tumor types, and prior to tumor formation. Our integrated imaging, genomic, and transcriptomic analyses reveal functional consequences in enhanced transcription activities and impaired genomic stability. We also demonstrate the potential of imaging higher-order chromatin disruption to detect high-risk precursors that cannot be distinguished by conventional pathology. Taken together, our findings reveal gradual decompaction and fragmentation of higher-order chromatin structure as an enabling characteristic in early carcinogenesis to facilitate malignant transformation, which may improve cancer diagnosis, risk stratification, and prevention.

Diallyl Trisulfide Inhibits Leptin-induced Oncogenic Signaling in Human Breast Cancer Cells but Fails to Prevent Chemically-induced Luminal-type Cancer in Rats.

Previous studies have demonstrated inhibitory effect of garlic component diallyl trisulfide (DATS) on growth of breast cancer cells in vitro and in vivo. This study investigated the effect of DATS on oncogenic signaling regulated by leptin, which plays an important role in breast carcinogenesis. Leptin-induced phosphorylation and nuclear translocation of STAT3 was inhibited significantly in the presence of DATS in MCF-7 (a luminal-type human breast cancer cell line) and MDA-MB-231 (a basal-like human breast cancer cell line). Leptin-stimulated cell proliferation, clonogenic cell survival, and migration and/or invasion ability in MCF-7 and/or MDA-MB-231 cells were also suppressed by DATS treatment. DATS exposure resulted in inhibition of leptin-stimulated expression of protein and/or mRNA levels of Bcl-2, Bcl-xL, Cyclin D1, vascular endothelial growth factor, and matrix metalloproteinase-2. Western blotting revealed a decrease in protein levels of phosphorylated STAT3 in breast cancer xenografts from DATS-treated mice when compared to controls in vivo. However, the incidence of N-methyl-N-nitrosourea-induced luminal-type breast cancer development in rats was not affected by oral administration of 5 mg/kg or 25 mg/kg DATS. The present study reveals that oncogenic signaling induced by leptin is inhibited in the presence of DATS but higher doses of this phytochemical may be required to achieve chemopreventive activity.