Uridine diphosphate-glucuronosyltransferase 2B15 D85Y gene polymorphism is associated with lower prostate cancer risk: a systematic review and meta-analysis

The UDP-Glycosyltransferase (UGT) Superfamily: New Members, New Functions, and Novel Paradigms

UDP-glycosyltransferases (UGTs) catalyze the covalent addition of sugars to a broad range of lipophilic molecules. This biotransformation plays a critical role in elimination of a broad range of exogenous chemicals and by-products of endogenous metabolism, and also controls the levels and distribution of many endogenous signaling molecules. In mammals, the superfamily comprises four families: UGT1, UGT2, UGT3, and UGT8. UGT1 and UGT2 enzymes have important roles in pharmacology and toxicology including contributing to interindividual differences in drug disposition as well as to cancer risk. These UGTs are highly expressed in organs of detoxification (e.g., liver, kidney, intestine) and can be induced by pathways that sense demand for detoxification and for modulation of endobiotic signaling molecules. The functions of the UGT3 and UGT8 family enzymes have only been characterized relatively recently; these enzymes show different UDP-sugar preferences to that of UGT1 and UGT2 enzymes, and to date, their contributions to drug metabolism appear to be relatively minor. This review summarizes and provides critical analysis of the current state of research into all four families of UGT enzymes. Key areas discussed include the roles of UGTs in drug metabolism, cancer risk, and regulation of signaling, as well as the transcriptional and posttranscriptional control of UGT expression and function. The latter part of this review provides an in-depth analysis of the known and predicted functions of UGT3 and UGT8 enzymes, focused on their likely roles in modulation of levels of endogenous signaling pathways.

UDP-glucuronosyltransferase genetic variation in North African populations: a comparison with African and European data

BACKGROUND

Genetic variation in glucuronosyltransferases (UGT) is crucial in drug metabolism and risk of some diseases.

AIM

To examine genetic variation in UGT in North African populations.

SUBJECTS AND METHODS

Allele frequencies of SNPs UGT1A4^24Thr, UGT1A4^48Val, UGT2B15^85Tyr, UGT2B15^523Thr and UGT2B17 CNV deletion from Morocco, Algeria, Tunisia and Libya were compared to European and Sub-Saharan populations.

RESULTS

North Africans are the group with the highest genetic heterogeneity given by internal differences in the occurrence of UGT2B17 deletion, UGT1A4^48Val and UGT1A4 haplotypes. UGT2B15 SNPs differentiate Sub-Saharans from the rest of the populations.

CONCLUSION

North African populations show a high frequency of carriers of UGT2B15^523Thr, a variant linked to an increased risk of prostate cancer. High Atlas Moroccans and Algerians show low frequency of UGT2B17^del, a variant associated with high concentrations of testosterone and oestradiol.

Dihydrotestosterone and cancer risk

PURPOSE OF REVIEW

Androgens have been implicated in prostate growth; however, the role of androgens in prostate cancer development is not clear. Furthermore, studies suggest a role for androgens in female-hormone-dependent cancers and common nonhormone dependent cancers. This study aims to review key studies and more recent studies of dihydrotestosterone (DHT) and cancer risk.

RECENT FINDINGS

Epidemiological studies are reassuring as they have not associated endogenous androgens with prostate cancer risk. Intraprostatic regulation of DHT is becoming recognized as an important area of research to clarify the role of DHT in prostate cancer development. In females, further understanding of intracrine regulation of sex hormones and interactions between androgens and estrogens in influencing breast and endometrial cancer risk are required. Studies show a signal for DHT in modulating lung and colorectal cancer growth; however, research in this area is relatively scarce and further studies are required to clarify these associations.

SUMMARY

Although concerns of prostate cancer risk remain, there is also potential for androgens to modulate the growth and development of other common cancers. Further research is required as this may have clinical implications.