Activation of AMP-Activated Protein Kinase by 3,39-Diindolylmethane (DIM) Is Associated with Human Prostate Cancer Cell Death \u3cem\u3eIn Vitro\u3c/em\u3e and \u3cem\u3eIn Vivo\u3c/em\u3e

There is a large body of scientific evidence suggesting that 3,39-Diindolylmethane (DIM), a compound derived from the digestion of indole-3-carbinol, which is abundant in cruciferous vegetables, harbors anti-tumor activity in vitro and in vivo. Accumulating evidence suggests that AMP-activated protein kinase (AMPK) plays an essential role in cellular energy homeostasis and tumor development and that targeting AMPK may be a promising therapeutic option for cancer treatment in the clinic. We previously reported that a formulated DIM (BR-DIM; hereafter referred as B-DIM) with higher bioavailability was able to induce apoptosis and inhibit cell growth, angiogenesis, and invasion of prostate cancer cells. However, the precise molecular mechanism(s) for the anti-cancer effects of B-DIM have not been fully elucidated. In the present study, we investigated whether AMP-activated protein kinase (AMPK) is a molecular target of B-DIM in human prostate cancer cells. Our results showed, for the first time, that B-DIM could activate the AMPK signaling pathway, associated with suppression of the mammalian target of rapamycin (mTOR), down-regulation of androgen receptor (AR) expression, and induction of apoptosis in both androgen-sensitive LNCaP and androgen-insensitive C4-2B prostate cancer cells. B-DIM also activates AMPK and down-regulates AR in androgen-independent C4-2B prostate tumor xenografts in SCID mice. These results suggest that B-DIM could be used as a potential anti-cancer agent in the clinic for prevention and/or treatment of prostate cancer regardless of androgen responsiveness, although functional AR may be required

The Proteasome Is a Molecular Target of Environmental Toxic Organotins

BACKGROUND: Because of the vital importance of the proteasome pathway, chemicals affecting proteasome activity could disrupt essential cellular processes. Although the toxicity of organotins to both invertebrates and vertebrates is well known, the essential cellular target of organotins has not been well identified. We hypothesize that the proteasome is a molecular target of environmental toxic organotins. OBJECTIVES: Our goal was to test the above hypothesis by investigating whether organotins could inhibit the activity of purified and cellular proteasomes and, if so, the involved molecular mechanisms and downstream, events. RESULTS: We found that some toxic organotins [e.g., triphenyltin (TPT)] can potently and preferentially inhibit the chymotrypsin-like activity of purified 20S proteasomes and human breast cancer cellular 26S proteasomes. Direct binding of tin atoms to cellular proteasomes is responsible for the observed irreversible inhibition. Inhibition of cellular proteasomes by TPT in several human cell lines results in the accumulation of ubiquitinated proteins and natural proteasome target proteins, accompanied by induction of cell death. CONCLUSIONS: The proteasome is one of the molecular targets of environmental toxic organotins in human cells, and proteasome inhibition by organotins contributes to their cellular toxicity

A review of factors influencing sensitive skin: an emphasis on built environment characteristics

BackgroundSensitive skin (SS) is a condition characterized by hyperreactivity. Impacting around 37 percent of the worldwide population and exerting an influence on the quality of life for affected individuals. Its prevalence rate has increased due to factors such as elevating stress levels and deteriorating environmental conditions. The exposome factors influencing SS have extended from demographic, biological attributes, and lifestyle to external environments. Built environments (BEs) have demonstrated as root drivers for changes in behaviors and environmental exposure which have the potential to trigger SS, but the review of the associations between BEs and SS is currently lacking.ObjectiveThis review aims to achieve two primary objectives: (1) Examine exposome factors that exert influence on SS at the individual and environmental levels. (2) Develop a theoretical framework that establishes a connection between BEs and SS, thereby offering valuable insights into the impact of the built environment on this condition.MethodsAn extensive literature search was carried out across multiple fields, including sociology, epidemiology, basic medicine, clinical medicine, and environmental research, with a focus on SS. To identify pertinent references, renowned databases such as PubMed, Web of Science, and CNKI were utilized.ResultsSS is the outcome of interactions between individual attributes and environmental factors. These influencing factors can be categorized into five distinct classes: (1) demographic and socioeconomic characteristics including age, gender, and race; (2) physiological and biological attributes such as emotional changes, skin types, sleep disorders, and menstrual cycles in women; (3) behavioral factors, such as spicy diet, cosmetic use, alcohol consumption, and physical exercise; (4) natural environmental features, including climate conditions and air pollution; (5) built environmental features such as population density, green space availability, road network density, and access to public transportation, also have the potential to affect the condition.ConclusionThe importance of interdisciplinary integration lies in its ability to ascertain whether and how BEs are impacting SS. By elucidating the role of BEs in conjunction with other factors in the onset of SS, we can provide guidance for future research endeavors and the formulation of interventions aimed at mitigating the prevalence of SS

Prodrugs of Fluoro-Substituted Benzoates of EGC as Tumor Cellular Proteasome Inhibitors and Apoptosis Inducers

The most potent catechin in green tea is (-)-epigallocatechin-3-gallate [(-)-EGCG], which, however, is unstable under physiological conditions. To discover more stable and more potent polyphenol proteasome inhibitors, we synthesized several novel fluoro-substituted (-)-EGCG analogs, named F-EGCG analogs, as well as their prodrug forms with all of -OH groups protected by acetate. We report that the prodrug form of one F-EGCG analog exhibited greater potency than the previously reported peracetate of (-)-EGCG to inhibit proteasomal activity, suppress cell proliferation, and induce apoptosis in human leukemia Jurkat T cells, demonstrating the potential of these compounds to be developed into novel anti-cancer and cancer-preventive agents

Clioquinol and pyrrolidine dithiocarbamate complex with copper to form proteasome inhibitors and apoptosis inducers in human breast cancer cells

INTRODUCTION: A physiological feature of many tumor tissues and cells is the tendency to accumulate high concentrations of copper. While the precise role of copper in tumors is cryptic, copper, but not other trace metals, is required for angiogenesis. We have recently reported that organic copper-containing compounds, including 8-hydroxyquinoline-copper(II) and 5,7-dichloro-8-hydroxyquinoline-copper(II), comprise a novel class of proteasome inhibitors and tumor cell apoptosis inducers. In the current study, we investigate whether clioquinol (CQ), an analog of 8-hydroxyquinoline and an Alzheimer's disease drug, and pyrrolidine dithiocarbamate (PDTC), a known copper-binding compound and antioxidant, can interact with copper to form cancer-specific proteasome inhibitors and apoptosis inducers in human breast cancer cells. Tetrathiomolybdate (TM), a strong copper chelator currently being tested in clinical trials, is used as a comparison. METHODS: Breast cell lines, normal, immortalized MCF-10A, premalignant MCF10AT1K.cl2, and malignant MCF10DCIS.com and MDA-MB-231, were treated with CQ or PDTC with or without prior interaction with copper, followed by measurement of proteasome inhibition and cell death. Inhibition of the proteasome was determined by levels of the proteasomal chymotrypsin-like activity and ubiquitinated proteins in protein extracts of the treated cells. Apoptotic cell death was measured by morphological changes, Hoechst staining, and poly(ADP-ribose) polymerase cleavage. RESULTS: When in complex with copper, both CQ and PDTC, but not TM, can inhibit the proteasome chymotrypsin-like activity, block proliferation, and induce apoptotic cell death preferentially in breast cancer cells, less in premalignant breast cells, but are non-toxic to normal/non-transformed breast cells at the concentrations tested. In contrast, CQ, PDTC, TM or copper alone had no effects on any of the cells. Breast premalignant or cancer cells that contain copper at concentrations similar to those found in patients, when treated with just CQ or PDTC alone, but not TM, undergo proteasome inhibition and apoptosis. CONCLUSION: The feature of breast cancer cells and tissues to accumulate copper can be used as a targeting method for anticancer therapy through treatment with novel compounds such as CQ and PDTC that become active proteasome inhibitors and breast cancer cell killers in the presence of copper

B-DIM activates AMPK signaling and inhibits AR expression in prostate tumor xenograft tissues.

<p>ICR SCID mice were implanted with C4-2B cells and treated with 5 mg/mouse of B-DIM by oral gavages daily for 4 wks. Tumor tissues were analyzed by immunohistochemistry using anti-phosphor-AMPKα (T172), phosphor-ACC (S79) or AR antibodies. The stained sections were visualized under the microscope (400×amplification). Unlike solvent-treated control, mice treated with B-DIM presented with activation of AMPK and significant loss of AR in tumor sections.</p

AMPK inhibitor Compound C can block AMPK activation by B-DIM in prostate cancer cells.

<p>Prostate cancer C4-2B and LNCaP cells were pre-treated with 20 µM of AMPK inhibitor Compound C (CC) for 6 hours, followed by co-treatment with indicated concentrations of B-DIM for 3 hours. Cell extracts of the treated cells were immunoblotted for anti-phosphor-AMPKα, phosphor-ACC or β-actin antibodies.</p

Treatment with B-DIM or metformin inhibits prostasphere-forming ability.

<p>C4-2B cells were treated with indicated doses of B-DIM (A, B) for 6 days. Treatment with different concentrations of metformin served as controls (C, D). After 6 days, prostasphere numbers were counted under the microscope and the proportion of sphere-generating cells was calculated by dividing the number of cells seeded by the number of prostaspheres (A, C). Prostaspheres from C4-2B cells treated with B-DIM (B) or metformin (D) were photographed and the results showed that 10 and 25 µM of B-DIM significantly reduced size and numbers of prostaspheres. n = 6, * P<0.05, ** P<0.01.</p

B-DIM activates the AMPK pathway, resulting in inhibition of AR and PSA expression and induction of apoptosis in prostate cancer cells.

<p>Human prostate cancer C4-2B (A) or LNCaP (B) cells were treated with indicated concentrations of B-DIM for 3 hours to measure protein levels of phosphor-AMPKα, AMPKα, phosphor-Raptor, phosphor-ACC, phosphor-mTOR, or for 24 hours to measure protein levels of AR, PSA or PARP cleavage by Western blot analysis. Measurement of β-actin served as loading controls. The numbers underneath the Western results of phosphor-AMPKα indicate quantified normalized phosphor-AMPKα and β-actin ratios.</p