Exposure of environmental trace elements in prostate cancer patients: A multiple metal analysis.

Prostate cancer (PCa) is the second leading cause of cancer-related deaths among men. To elucidate the connection between trace elements (arsenic: As, cadmium: Cd, lead: Pb, chromium: Cr, and nickel: Ni) and the risk of PCa, we analyzed trace element levels in the serum, urine, and tissues of PCa patients, while also examining their smoking status. We correlated these levels with their smoking habits. Notably, levels of Cd (P ≤ 0.05) and As (P ≤ 0.01) were significantly higher in the tumor tissue than in adjacent tissues. No significant differences were observed in the levels of Pb, Cr and Ni. Additionally, urinary Cd levels in 70% and arsenic levels in 2.3% of the PCa cohort were markedly higher than the CDC-reported cutoff (Cd ≤ 0.185 µg/L & As ≤100 µg/L). None displayed elevated levels of urinary Pb, Cr, and Ni. Conversely, in serum samples, the concentration of arsenic exceeded the CDC-determined limit (As ≤1.0 µg/L) in 31.69% of PCa patients. However, only 7.04% of patients had higher serum Cd levels than the CDC standard values (Cd ≤ 0.315 µg/L), while all PCa patients exceeded the Cr CDC limit (Cr ≤ 0.16 µg/L) and the Ni CDC limit (Ni ≤ 0.2 µg/L). On the contrary, no significant differences were observed in serum Pb (Pb ≤ 35.0 µg/L). Our findings establish a positive link between Cd and arsenic tissue concentrations and the risk of PCa. Subsequent studies are essential to determine whether elevated trace element levels pose a risk for the development of prostate carcinogenesis. Interestingly, among the PCa cohort comprising smokers, notably higher Cd levels were observed only in tumor tissues (P ≤ 0.01) and urine (P ≤ 0.05) compared to other elements or in other specimens.

Corrigendum: A small molecule inhibitor of Notch1 modulates stemness and suppresses breast cancer cell growth.

[This corrects the article DOI: 10.3389/fphar.2023.1150774.].

A small molecule inhibitor of Notch1 modulates stemness and suppresses breast cancer cell growth.

Although breast cancer stem cells (BCSCs) are well characterized, molecularly targeting and eradicating this sub-population remains a challenge in the clinic. Recent studies have explored several signaling pathways that govern stem cell activation: We and others established that the Notch1 signaling plays a significant role in the proliferation, survival, and differentiation of BCSCs. Earlier, we reported that a newly developed small molecule, ASR490, binds to the negative regulatory region (NRR: The activation switch of the Notch receptor) of Notch1. In vitro results demonstrated that ASR490 significantly inhibited BCSCs (ALDH+ and CD44+/CD24-) and breast cancer (BC) growth at nM concentrations, and subsequently inhibited the colony- and mammosphere-forming abilities of BCSCs and BCs. ASR490 downregulated the expressions of Notch1 intracellular domain (NICD: The active form of Notch1) and its downstream effectors Hey1 and HES1. Inhibition of Notch1-NICD facilitated autophagy-mediated growth inhibition by triggering the fusion of autophagosome and autolysosome in BCSCs. ASR490 was found to be non-toxic to healthy cells as compared to existing Notch1 inhibitors. Moreover, oral administration of ASR490 abrogated BCSC and BC tumor growth in the in vivo xenograft models. Together our results indicate that ASR490 is a potential therapeutic agent that inhibits BC tumor growth by targeting and abolishing Notch1 signaling in BCSCs and BC cells.

Urolithin A analog inhibits castration-resistant prostate cancer by targeting the androgen receptor and its variant, androgen receptor-variant 7.

We investigated the efficacy of a small molecule ASR-600, an analog of Urolithin A (Uro A), on blocking androgen receptor (AR) and its splice variant AR-variant 7 (AR-V7) signaling in castration-resistant prostate cancer (CRPC). ASR-600 effectively suppressed the growth of AR+ CRPC cells by inhibiting AR and AR-V7 expressions; no effect was seen in AR- CRPC and normal prostate epithelial cells. Biomolecular interaction assays revealed ASR-600 binds to the N-terminal domain of AR, which was further confirmed by immunoblot and subcellular localization studies. Molecular studies suggested that ASR-600 promotes the ubiquitination of AR and AR-V7 resulting in the inhibition of AR signaling. Microsomal and plasma stability studies suggest that ASR-600 is stable, and its oral administration inhibits tumor growth in CRPC xenografted castrated and non-castrated mice. In conclusion, our data suggest that ASR-600 enhances AR ubiquitination in both AR+ and AR-V7 CRPC cells and inhibits their growth in vitro and in vivo models.

Antiandrogen-Equipped Histone Deacetylase Inhibitors Selectively Inhibit Androgen Receptor (AR) and AR-Splice Variant (AR-SV) in Castration-Resistant Prostate Cancer (CRPC).

BACKGROUND: Epigenetic modification influences androgen receptor (AR) activation, often resulting in prostate cancer (PCa) development and progression. Silencing histone-modifying enzymes (histone deacetylases-HDACs) either genetically or pharmacologically suppresses PCa proliferation in preclinical models of PCa; however, results from clinical studies were not encouraging. Similarly, PCa patients eventually become resistant to androgen ablation therapy (ADT). Our goal is to develop dual-acting small molecules comprising antiandrogen and HDAC-inhibiting moieties that may overcome the resistance of ADT and effectively suppress the growth of castration-resistant prostate cancer (CRPC). METHODS: Several rationally designed antiandrogen-equipped HDAC inhibitors (HDACi) were synthesized, and their efficacy on CRPC growth was examined both in vitro and in vivo. RESULTS: While screening our newly developed small molecules, we observed that SBI-46 significantly inhibited the proliferation of AR+ CRPC cells but not AR- CRPC and normal immortalized prostate epithelial cells (RWPE1) or normal kidney cells (HEK-293 and VERO). Molecular analysis confirmed that SBI-46 downregulated the expressions of both AR+ and AR-splice variants (AR-SVs) in CRPC cells. Further studies revealed the downregulation of AR downstream (PSA) events in CRPC cells. The oral administration of SBI-46 abrogated the growth of C4-2B and 22Rv1 CRPC xenograft tumors that express AR or both AR and AR-SV in xenotransplanted nude mice models. Further, immunohistochemical analysis confirmed that SBI-46 inhibits AR signaling in xenografted tumor tissues. CONCLUSION: These results demonstrate that SBI-46 is a potent agent that inhibits preclinical models of CRPC by downregulating the expressions of both AR and AR-SV. Furthermore, these results suggest that SBI-46 may be a potent compound for treating CRPC.

Molecular interplay between NOX1 and autophagy in cadmium-induced prostate carcinogenesis.

Chronic exposure to cadmium (Cd), a class I carcinogen, leads to malignant transformation of normal prostate epithelial cells (RWPE-1). The constant generation of Cd-induced ROS and resulting ER stress induces cellular responses that are needed for cell survival, and autophagy has an important role in this process. However, the mechanisms that regulate Cd-induced ROS and how these differ in terms of acute and chronic cadmium exposure remain unexplained. Here, we show that acute or chronic Cd exposure facilitates NOX1 assembly by activating its cytosolic regulators p47phox and p67phox in RWPE-1 cells. Upregulation of NOX1 complex proteins and generation of ROS activates unfolded protein response (UPR) via phosphorylation of protein kinase RNA-like endoplasmic reticulum kinase (PERK), eukaryotic initiation factor 2 alpha (eIF2α), and selective translation of activating transcription factor 4 (ATF4). Chronic Cd exposure constantly activates NOX1 complex and generates consistent ROS and ER stress that led to defective autophagy, wherein ATG5 expression is downregulated in contrast to acute Cd exposure. As a result, selective/defective autophagy creates depletion of autophagosome-lysosome fusion that gives a survival advantage to transforming cells, which is not available to RWPE-1 cells acutely exposed to Cd. Knockdown of key molecules in a lockstep manner directly affects the most downstream autophagy pathways in transforming cells. Overall, this study demonstrates that assembly of NOX1 complex proteins is indispensable for Cd-induced persistent ROS and controls ER stress-induced defective autophagy in mice and humans.

A Comprehensive Transcriptomic Analysis of Arsenic-Induced Bladder Carcinogenesis.

Arsenic (sodium arsenite: NaAsO2) is a potent carcinogen and a known risk factor for the onset of bladder carcinogenesis. The molecular mechanisms that govern arsenic-induced bladder carcinogenesis remain unclear. We used a physiological concentration of NaAsO2 (250 nM: 33 µg/L) for the malignant transformation of normal bladder epithelial cells (TRT-HU1), exposed for over 12 months. The increased proliferation and colony-forming abilities of arsenic-exposed cells were seen after arsenic exposure from 4 months onwards. Differential gene expression (DEG) analysis revealed that a total of 1558 and 1943 (padj < 0.05) genes were deregulated in 6-month and 12-month arsenic-exposed TRT-HU1 cells. The gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that cell proliferation and survival pathways, such as the MAPK, PI3K/AKT, and Hippo signaling pathways, were significantly altered. Pathway analysis revealed that the enrichment of stem cell activators such as ALDH1A1, HNF1b, MAL, NR1H4, and CDH1 (p < 0.001) was significantly induced during the transformation compared to respective vehicle controls. Further, these results were validated by qPCR analysis, which corroborated the transcriptomic analysis. Overall, the results suggested that stem cell activators may play a significant role in facilitating the arsenic-exposed cells to gain a survival advantage, enabling the healthy epithelial cells to reprogram into a cancer stem cell phenotype, leading to malignant transformation.

Recent Advances in the Chemistry and Therapeutic Evaluation of Naturally Occurring and Synthetic Withanolides.

Natural products are a major source of biologically active compounds that make promising lead molecules for developing efficacious drug-like molecules. Natural withanolides are found in many flora and fauna, including plants, algae, and corals, that traditionally have shown multiple health benefits and are known for their anti-cancer, anti-inflammatory, anti-bacterial, anti-leishmaniasis, and many other medicinal properties. Structures of these withanolides possess a few reactive sites that can be exploited to design and synthesize more potent and safe analogs. In this review, we discuss the literature evidence related to the medicinal implications, particularly anticancer properties of natural withanolides and their synthetic analogs, and provide perspectives on the translational potential of these promising compounds.

The role of autophagy in metal-induced urogenital carcinogenesis.

Environmental and/or occupational exposure to metals such as Arsenic (As), Cadmium (Cd), and Chromium (Cr) have been shown to induce carcinogenesis in various organs, including the urogenital system. However, the mechanisms responsible for metal-induced carcinogenesis remain elusive. We and others have shown that metals are potent inducers of autophagy, which has been suggested to be an adaptive stress response to allow metal-exposed cells to survive in hostile environments. Albeit few, recent experimental studies have shown that As and Cd promote tumorigenesis via autophagy and that inhibition of autophagic signaling suppressed metal-induced carcinogenesis. In light of the newly emerging role of autophagic involvement in metal-induced carcinogenesis, the present review focuses explicitly on the mechanistic role of autophagy and potential signaling pathways involved in As-, Cd-, and Cr-induced urogenital carcinogenesis.

Discovery of new AKT1 inhibitors by combination of in silico structure based virtual screening approaches and biological evaluations.

Communicated by Ramaswamy H. Sarma.

Diagnostic molecular markers predicting aggressive potential in low-grade prostate cancer.

Currently, clinicians rely on clinical nomograms to stratify progression risk at the time of diagnosis in patients with prostate cancer (CaP). However, these tools may not accurately distinguish aggressive potential in low-grade CaP. The current study determined the diagnostic potential of 3 molecular markers (ROCK1, RUNX3, and miR-301a) in terms of their ability to identify which low-grade tumors are likely to progress. Real-time PCR and immunohistochemical analysis were used to assess ROCK1, RUNX3, and miR-301a expression profiles in 118 serum and needle biopsy specimens. Expressions of ROCK1 and miR-301a were found to be significantly higher in Gleason 6 and 7 CaP as compared to BPH, while an inverse trend was observed with RUNX3. Further, incorporation of all 3 molecular markers significantly improved clinical nomograms' diagnostic accuracy and correlated with disease progression. Hence, in conclusion, the inclusion of these 3 molecular markers identified aggressive phenotype and predicted disease progression in low-grade CaP tumors at the time of diagnosis.

ASR490, a Small Molecule, Overrides Aberrant Expression of Notch1 in Colorectal Cancer.

Notch1 activation triggers significant oncogenic signaling that manifests as enhanced metastatic potential and tumorigenesis in colorectal cancer. Novel small-molecule inhibitors, mainly plant-derived analogs, have low toxicity profiles and higher bioavailability. In this study, we have developed a small molecule, ASR490, by modifying structure of naturally occurring compound Withaferin A. ASR490 showed a growth-inhibitory potential by downregulating Notch1 signaling in HCT116 and SW620 cell lines. Docking studies and thermal shift assays confirmed that ASR490 binds to Notch1, whereas no changes in Notch2 and Notch3 expression were seen in colorectal cancer cells. Notch1 governs epithelial-to-mesenchymal transition signaling and is responsible for metastasis, which was abolished by ASR490 treatment. To further confirm the therapeutic potential of ASR490, we stably overexpressed Notch1 in HCT-116 cells and determined its inhibitory potential in transfected colorectal cancer (Notch1/HCT116) cells. ASR490 effectively prevented cell growth in both the vector (P = 0.005) and Notch1 (P = 0.05) transfectants. The downregulation of Notch1 signaling was evident, which corresponded with downregulation of mesenchymal markers, including N-cadherin and ß-catenin and induction of E-cadherin in HCT-116 transfectants. Intraperitoneal administration of a 1% MTD dose of ASR490 (5 mg/kg) effectively suppressed the tumor growth in control (pCMV/HCT116) and Notch1/HCT116 in xenotransplanted mice. In addition, downregulation of Notch1 and survival signaling in ASR-treated tumors confirmed the in vitro results. In conclusion, ASR490 appears to be a potent agent that can inhibit Notch1 signaling in colorectal cancer.

A Review on Notch Signaling and Colorectal Cancer.

Colorectal cancer (CRC) has one of the highest mortality rates despite the advancement of treatment options. Aggressive CRC remains difficult to treat owing to the activation of oncogenic signaling pathways such as the Notch signaling pathway. The role of Notch receptors varies according to the difference in their structures; in particular, aberrant activation of Notch1 has been attributed to the severity of CRC. Notch1 activation in CRC is inhibited by small molecule inhibitors that target γ-secretase, an enzyme responsible for the third and last cleavage step of Notch receptors. γ-Secretase also produces the intracellular domain that finally carries out cellular functions by activating downstream effectors. However, most inhibitors block γ-secretase non-selectively and cause severe toxicity. Plant-source-derived small molecules, monoclonal antibodies, biological molecules (such as SiRNAs), and compounds targeting the Notch1 receptor itself or the downstream molecules such as HES1 are some of the options that are in advanced stages of clinical trials. The Negative Regulatory Region (NRR), which plays a central role in the transduction of Notch1 signaling in the event of ligand-dependent and ligand-independent Notch1 processing is also being targeted specifically by monoclonal antibodies (mAbs) to prevent aberrant Notch1 activation. In this review, we discuss the role of Notch1 in CRC, particularly its metastatic phenotype, and how mutations in Notch1, specifically in its NRR region, contribute to the aberrant activation of Notch1 signaling, which, in turn, contributes to CRC pathogenesis. We also discuss prevailing and emerging therapies that target the Notch1 receptor and the NRR region, and we highlight the potential of these therapies in abrogating Notch signaling and, thus, CRC development and progression.

ASR488, a novel small molecule, activates an mRNA binding protein, CPEB1, and inhibits the growth of bladder cancer.

Due to a lack of mechanistic insights, muscle-invasive bladder cancer (MIBC) remains incurable and is one of the most lethal types of cancer in the United States. The present study investigated changes in the molecular signatures of MIBC cells (TCCSUP and HT1376) after treatment with a novel small molecule, ASR488, to gain knowledge of the mechanisms that inhibited MIBC cell growth. ASR488 treatment initiated apoptotic signaling in MIBC cells. Pathway enrichment analysis was used to analyze the changes in function of differentially expressed genes. Gene Ontology analysis, as well as Kyoto Encyclopedia of Genes and Genomes analysis, was also performed. These analyses along with reactome pathway enrichment analyses indicated that the genes upregulated in the ASR488-treated cells are involved in focal adhesion, neurotrophin signaling, p53 signaling, endoplasmic reticulum functioning in terms of protein processing, and pathways related to bladder cancer. The genes downregulated in ASR488-treated MIBC cells were mainly involved in DNA replication, mismatch repair, RNA degradation, nucleotide excision repair and TGFß signaling (P<0.05). Furthermore, reverse transcription-quantitative PCR analysis revealed an increase in transcripts of the most upregulated genes in ASR 488-treated MIBC cells: CPEB1 (36-fold), IL11 (30-fold), SFN (20.12-fold) and CYP4F11 (15.8-fold). In conclusion, the analysis of biological functions of the most differentially expressed genes revealed possible mechanisms that may be associated with the aggressiveness of MIBC.

Chronic exposure to cadmium induces a malignant transformation of benign prostate epithelial cells.

Epidemiological evidence suggests that cadmium (Cd) is one of the causative factors of prostate cancer, but the effect of Cd on benign prostatic hyperplasia (BPH) remains unclear. This study aimed to determine whether Cd exposure could malignantly transform BPH1 cells and, if so, to dissect the mechanism of action. We deciphered the molecular signaling responsible for BPH1 transformation via RNA-sequencing and determined that Cd induced the expression of zinc finger of the cerebellum 2 (ZIC2) in BPH1 cells. We noted Cd exposure increased ZIC2 expression in the Cd-transformed BPH1 cells that in turn promoted anchorage-independent spheroids and increased expression of stem cell drivers, indicating their role in stem cell renewal. Subsequent silencing of ZIC2 expression in transformed cells inhibited spheroid formation, stem cell marker expression, and tumor growth in nude mice. At the molecular level, ZIC2 interacts with the glioma-associated oncogene family (GLI) zinc finger 1 (GLI1), which activates prosurvival factors (nuclear factor NFκB, B-cell lymphoma-2 (Bcl2), as well as an X-linked inhibitor of apoptosis protein (XIAP)) signaling in Cd-exposed BPH1 cells. Conversely, overexpression of ZIC2 in BPH1 cells caused spheroid formation confirming the oncogenic function of ZIC2. ZIC2 activation and GLI1 signaling induction by Cd exposure in primary BPH cells confirmed the clinical significance of this oncogenic function. Finally, human BPH specimens had increased ZIC2 versus adjacent healthy tissues. Thus, we report direct evidence that Cd exposure induces malignant transformation of BPH via activation of ZIC2 and GLI1 signaling.

Profiling of differentially expressed genes in cadmium-induced prostate carcinogenesis.

The aim of the present study was to investigate the genetic signatures of cadmium-transformed prostate epithelial (CTPE) cells and to identify the potential molecular signaling involved in their malignant transformation. The dataset contained normal prostate epithelial (RWPE-1) and CTPE cells. To further examine the biological functions of the identified differentially expressed genes (DEGs), Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Reactome pathway enrichment analyses were performed. In total, 2357 DEGs were identified, including 1083 upregulated genes and 1274 downregulated genes. GO, KEGG, and Reactome pathway enrichment analyses indicated that upregulated genes were significantly enriched in ECM-receptor, focal adhesion, TGFß signaling, and syndecan interactions, while downregulated genes were mainly involved in cell cycle regulation, arachidonic acid metabolism, oxidative phosphorylation, and folate biosynthesis (p < .05). The top upregulated (SATB1 (p < .0001), EYA2 (p < .0001) and KPNA7 (p < .0027)) and downregulated (PITX2 (p < .0007), PDLIM4 (p < .0020) and FABP5 (p < .0007)) genes were further validated via qRT-PCR analysis. In conclusion, the present study profiled DEGs in RWPE-1 and CTPE cells and identified gene pathways that may be associated with malignant transformation and tumor progression.

Combination of androgen receptor inhibitor and cisplatin, an effective treatment strategy for urothelial carcinoma of the bladder.

PURPOSE: The role of androgen receptor (AR) signaling in bladder cancer (BCa) is not fully characterized. This study aimed to delineate the role of AR signaling in BCa and to determine whether the combination of AR inhibitor, Enzalutamide (Enz), and Cisplatin (Cis) efficiently inhibit the growth of BCa cells. METHODS: AR expression was determined in 89 human urothelial BCa specimens by immunohistochemistry. A panel of BCa cell lines was treated with Cis, Enz, or a combination of both (Enz + Cis). We determined the expression of AR, changes in apoptotic signaling, DNA damage, and analyzed effect on epithelial mesenchymal transformation markers. RESULT: AR expression was detected in 61.4% of tumors from male BCa patients. Inhibition of AR signaling by Enz effectively inhibited the growth of AR+ BCa cells by inducing apoptosis (26%) in AR+ TCCSUP (P = 0.0201) and J82 (15%, P = 0.0386) cells. Interestingly, Enz + Cis synergistically inhibited the proliferation of BCa cells even at low concentrations by inducing proapoptotic signaling in AR+ BCa cells. Invasive and migratory potential of TCCSUP and J82 cells were reduced with Enz + Cis treatment, and associated with down-regulation of mesenchymal markers. CONCLUSIONS: A high percentage of the bladder tumors from male patients in our cohort expressed AR. The combination of Enz and Cis synergistically inhibited growth of BCa cells more efficiently than single agent alone. This supports the rationale for future investigation of AR antagonists in combination with standard chemotherapy in MIBC.

Induction of endoplasmic reticulum stress might be responsible for defective autophagy in cadmium-induced prostate carcinogenesis.

Earlier, we reported that chronic cadmium (Cd)-exposure to prostate epithelial (RWPE-1) cells causes defective autophagy, which leads to the transformation of a malignant phenotype in both in vitro and in vivo models. However, the upstream events responsible for defective autophagy are yet to be delineated. The present study suggests that chronic Cd exposure induces endoplasmic reticulum (ER) stress that triggers the phosphorylation of stress transducers [protein kinase R-like ER Kinase- (PERK), eukaryotic translation initiation factor 2-alpha- (eIF2-α) and Activating Transcription Factor 4 -(ATF-4)], resulting in defective autophagy that protects Cd-exposed RWPE-1 cells. On the other hand, inhibition of the ATF4 stress inducer by siRNA blocked the Cd-induced defective autophagy in transforming cells. While dissecting the upstream activators of ER stress, we found that increased expression of reactive oxygen species (ROS) is responsible for ER stress in Cd-exposed RWPE-1 cells. Overexpression of antioxidants (SOD1/SOD2) mitigates Cd-induced ROS that results in inhibition of ER stress and autophagy in prostate epithelial cells. These results suggest that the induction of ROS and subsequent ER stress are responsible for defective autophagy in Cd-induced transformation in prostate epithelial cells.

miR-301a expression: Diagnostic and prognostic marker for prostate cancer.

BACKGROUND: Prostate-specific antigen screening for prostate cancer (CaP) remains controversial. This study establishes the role of microRNA 301a (miR-301a) as a supplemental biomarker that can distinguish between patients with benign prostate hyperplasia and clinically significant CaP. We evaluate the ability of miR-301a to predict the adverse pathology of CaP. METHODS: In the first cohort, serum and prostate tumor samples were obtained from thirteen patients with Benign prostate hyperplasia (BPH), twelve patients with Gleason 6, and sixteen patients with Gleason 7 prostate adenocarcinoma. In the second cohort, 40 prostatectomy cases were selected (BPH:12, Gleason 6:12 and Gleason 7:16). MiRNA was extracted from serum and tumor samples. Quantitative reverse transcription-polymerase chain reaction was performed for detection of miR-301a. To understand the molecular role of miR-301a, we performed cell viability, Western blots, promoter analysis, overexpression, and silencing studies in BPH and DU-145 cell lines. RESULTS: MiR-301a demonstrated a significantly higher expression in both serum and tumor tissue in patients with CaP when compared to patients with BPH (P = 0.011 and 0.013 for serum and tissue expression, respectively). Expression of miR-301a in prostatectomy specimens correlated with increased Gleason score. We demonstrated that miR-301a inhibited the pro-apoptotic function of RUNX3, and activated ROCK1-mediated pro-survival signal in CaP. Silencing miR-301a initiated the pro-apoptotic function of RUNX3 by inhibiting ROCK1 expression in CaP cells. CONCLUSIONS: Expression of miR-301a could be a valuable adjunct tool for stratifying patients with elevated prostate-specific antigen, as well as those diagnosed with CaP. Including the miR-301a as an additional variable in MSKCC post-prostatectomy nomogram improved its ability in facilitating clinical decision-making.

The chemopreventive effect of withaferin A on spontaneous and inflammation-associated colon carcinogenesis models.

Chemopreventive effects and associated mechanisms of withaferin A (WA) against intestinal and colon carcinogenesis remain unknown. We investigated the chemopreventive effect of WA on transgenic adenomatous polyposis coli (APCMin/+) mouse and chemically induced azoxymethane/dextran sodium sulfate (AOM/DSS) models of intestinal and colon carcinogenesis. Oral WA administration (4 and 3 mg/kg) inhibited tumor initiation and progression of intestinal polyps formation in APCMin/+ mice and colon carcinogenesis in the AOM/DSS mouse model. WA-administered mice showed a significant reduction in both number [duodenum, 33% (P > 0.05); jejunum, 32% (P < 0.025); ileum, 43% ( P < 0.001); and colon 59% (P < 0.01] and size of polyps in APCMin/+ mice compared with the respective controls. Similarly, tumor multiplicity was significantly reduced (P < 0.05) in the colon of WA-administered AOM/DSS mice. Pathological analysis showed reduced adenomas and tissue inflammation in WA-administered mouse models. Molecular studies suggested that WA inhibited the expression of inflammatory (interluekin-6, tumor necrosis factor-alpha and cyclooxygenase-2), pro-survival (pAKT, Notch1 and NF-κB) markers in APCMin/+ and AOM/DSS models. The results suggest that WA is a potent agent for preventing colon carcinogenesis and further investigation is required to show clinical utility of the agent.