Expression of UDP Glucuronosyltransferases 2B15 and 2B17 is associated with methylation status in prostate cancer cells

Identification of UDP-Glucuronosyltransferase 2B15 (UGT2B15) as a Target for IGF1 and Insulin Action

Normal growth and development in mammals are tightly controlled by numerous genetic factors and metabolic conditions. The growth hormone (GH)-insulin-like growth factor-1 (IGF1) hormonal axis is a key player in the regulation of these processes. Dysregulation of the GH-IGF1 endocrine system is linked to a number of pathologies, ranging from growth deficits to cancer. Laron syndrome (LS) is a type of dwarfism that results from mutation of the GH receptor (GHR) gene, leading to GH resistance and short stature as well as a number of metabolic abnormalities. Of major clinical relevance, epidemiological studies have shown that LS patients do not develop cancer. While the mechanisms associated with cancer protection in LS have not yet been elucidated, genomic analyses have identified a series of metabolic genes that are over-represented in LS patients. We hypothesized that these genes might constitute novel targets for IGF1 action. With a fold-change of 11.09, UDP-glucuronosyltransferase 2B15 (UGT2B15) was the top up-regulated gene in LS. The UGT2B15 gene codes for an enzyme that converts xenobiotic substances into lipophilic compounds and thereby facilitates their clearance from the body. We investigated the regulation of UGT2B15 gene expression by IGF1 and insulin. Both hormones inhibited UGT2B15 mRNA levels in endometrial and breast cancer cell lines. Regulation of UGT2B15 protein levels by IGF1/insulin, however, was more complex and not always correlated with mRNA levels. Furthermore, UGT2B15 expression was dependent on p53 status. Thus, UGT2B15 mRNA levels were higher in cell lines expressing a wild-type p53 compared to cells containing a mutated p53. Animal studies confirmed an inverse correlation between UGT2B15 and p53 levels. In summary, increased UGT2B15 levels in LS might confer upon patient’s protection from genotoxic damage.

Impact of DNA methylation on ADME gene expression, drug disposition and efficacy

Interindividual differences in drug response have always existed in clinical treatment. Genes involved in drug absorption, distribution, metabolism, and excretion (ADME) play an important role in the process of pharmacokinetics. The effects of genetic polymorphism and nuclear receptors on the expression of drug metabolism enzymes and transporters can only explain some individual differences in clinical treatment. Several key ADME genes have been demonstrated to be regulated by epigenetic mechanisms that can potentially affect interindividual variability in medical treatment. Emerging studies have focused on the importance of DNA methylation for ADME gene expression and for drug response. Among them, the most studied is anti-tumor drugs, and followed by anti-tuberculous and anti-platelet drugs. Therefore, we provide an epigenetics perspective on variability in drug response. The review summarizes the correlation between ADME gene expression and DNA methylation, including the exact methylation locations, and focuses on the corresponding drug disposition and effects to illuminate interindividual differences in clinical medication.

Altered glucuronidation deregulates androgen dependent response profiles and signifies castration resistance in prostate cancer

Glucuronidation controls androgen levels in the prostate and the dysregulation of enzymes in this pathway is associated with castration resistant prostate cancer. UDP-glucose dehydrogenase (UGDH) produces UDP-glucuronate, the essential precursor for glucuronidation, and its expression is elevated in prostate cancer. We compared protein and metabolite levels relevant to the glucuronidation pathway in five prostate cancer patient-derived xenograft models paired with their isogenic counterparts that were selected in vivo for castration resistant (CR) recurrence. All pairs showed changes in UGDH and associated enzymes and metabolites that were consistent with those we found in an isogenic androgen dependent (AD) and CR LNCaP prostate cancer model. Ectopic overexpression of UGDH in LNCaP AD cells blunted androgen-dependent gene expression, increased proteoglycan synthesis, significantly increased cell growth compared to controls, and eliminated dose responsive growth suppression with enzalutamide treatment. In contrast, the knockdown of UGDH diminished proteoglycans, suppressed androgen dependent growth irrespective of androgens, and restored androgen sensitivity in CR cells. Importantly, the knockdown of UGDH in both LNCaP AD and CR cells dramatically sensitized these cells to enzalutamide. These results support a role for UGDH in androgen responsiveness and a target for therapeutic strategies in advanced prostate cancer.

δ-Catenin Participates in EGF/AKT/p21Waf Signaling and Induces Prostate Cancer Cell Proliferation and Invasion

Prostate cancer (PCa) is the second most leading cause of death in males. Our previous studies have demonstrated that δ-catenin plays an important role in prostate cancer progression. However, the molecular mechanism underlying the regulation of δ-catenin has not been fully explored yet. In the present study, we found that δ-catenin could induce phosphorylation of p21^Waf and stabilize p21 in the cytoplasm, thus blocking its nuclear accumulation for the first time. We also found that δ-catenin could regulate the interaction between AKT and p21, leading to phosphorylation of p21 at Thr-145 residue. Finally, EGF was found to be a key factor upstream of AKT/δ-catenin/p21 for promoting proliferation and metastasis in prostate cancer. Our findings provide new insights into molecular controls of EGF and the development of potential therapeutics targeting δ-catenin to control prostate cancer progression.