Butyrate induces expression of 17β-hydroxysteroid dehydrogenase type 1 in HT29 and SW707 colorectal cancer cells

Role of hydroxysteroid (17beta) dehydrogenase type 1 in reproductive tissues and hormone-dependent diseases

Abnormal synthesis and metabolism of sex steroids is involved in the pathogenesis of various human diseases, such as endometriosis and cancers arising from the breast and uterus. Steroid biosynthesis is a multistep enzymatic process proceeding from cholesterol to highly active sex steroids via different intermediates. Human Hydroxysteroid (17beta) dehydrogenase 1 (HSD17B1) enzyme shows a high capacity to produce the highly active estrogen, estradiol, from a precursor hormone, estrone. However, the enzyme may also play a role in other steps of the steroid biosynthesis pathway. In this article, we have reviewed the literature on HSD17B1, and summarize the role of the enzyme in hormone-dependent diseases in women as evidenced by preclinical studies.

Transcript level of AKR1C3 is down-regulated in gastric cancer

Steroid hormones have been shown to play a role in gastric carcinogenesis. Large amounts of steroid hormones are locally produced in the peripheral tissues of both genders. Type 5 of 17β-hydroxysteroid dehydrogenase, encoded by the AKR1C3 gene, plays a pivotal role in both androgen and estrogen metabolism, and its expression was found to be deregulated in different cancers. In this study we measured AKR1C3 transcript and protein levels in nontumoral and primary tumoral gastric tissues, and evaluated their association with some clinicopathological features of gastric cancer (GC). We found decreased levels of AKR1C3 transcript (p < 0.0001) and protein (p = 0.0021) in GC tissues compared with the adjacent, apparently histopathologically normal, mucosa. Lower levels of AKR1C3 transcript were observed in diffuse and intestinal types of GC, whereas AKR1C3 protein levels were decreased in tumors with multisite localization, in diffuse histological type, T3, T4, and G3 grades. We also determined the effect of the histone deacetylase inhibitor sodium butyrate (NaBu) on AKR1C3 expression in EPG 85-257 and HGC-27 GC cell lines. We found that NaBu elevates the levels of both AKR1C3 transcript and protein in the cell lines we investigated. Together, our results suggest that decreased expression of AKR1C3 may be involved in development of GC and can be restored by NaBu.

Intracrine oestrogen production and action in breast cancer: an epigenetic focus

Epigenome changes have been widely demonstrated to contribute to the initiation and progression of a vast array of cancers including breast cancer. The reversible process of many epigenetic modifications is thus an attractive feature for the development of novel therapeutic measures. In oestrogen receptor α (hereinafter referred to as ER) positive tumours, endocrine therapies have proven beneficial in patient care, particularly in postmenopausal women where two-thirds of tumours are oestrogen dependent. However, resistance to such therapies is a common feature amongst individuals. In the current review, we discuss the influence that epigenetics has on oestrogen dependent breast cancers, in particular (i) the production of intracrine oestrogen in postmenopausal women, (ii) the action of oestrogen on epigenetic processes, and (iii) the links between epigenetics and endocrine resistance and the current advancements in epigenetic therapy that target this process. This article is part of a Special Issue entitled 'CSR 2013'.

Habitat degradation impacts black howler monkey (Alouatta pigra) gastrointestinal microbiomes

The gastrointestinal (GI) microbiome contributes significantly to host nutrition and health. However, relationships involving GI microbes, their hosts and host macrohabitats remain to be established. Here, we define clear patterns of variation in the GI microbiomes of six groups of Mexican black howler monkeys (Alouatta pigra) occupying a gradation of habitats including a continuous evergreen rainforest, an evergreen rainforest fragment, a continuous semi-deciduous forest and captivity. High throughput microbial 16S ribosomal RNA gene sequencing indicated that diversity, richness and composition of howler GI microbiomes varied with host habitat in relation to diet. Howlers occupying suboptimal habitats consumed less diverse diets and correspondingly had less diverse gut microbiomes. Quantitative real-time PCR also revealed a reduction in the number of genes related to butyrate production and hydrogen metabolism in the microbiomes of howlers occupying suboptimal habitats, which may impact host health.

Reduced expression of steroid sulfatase in primary colorectal cancer

Colorectal cancer (CRC) is considered an estrogen-dependent malignancy, and intratissue estrogen concentration can be controlled by steroid sulfatase (STS). Little is known about changes in the expression of STS during the development of CRC. Therefore, we analysed the STS mRNA levels in primary colonic adenocarcinoma tissues and adjacent histopathologically unchanged colonic mucosa from patients who underwent radical colon resection (n=90). We found a statistically significant decrease in STS transcript levels in CRC (P=0.0453). Moreover, we found that sodium butyrate (NaBu) significantly upregulated STS transcript levels in DLD-1 and HCT116 CRC cells. Our results suggest that STS expression can be decreased in the process of large intestinal carcinogenesis. Moreover, we observed that NaBu might increase STS expression in CRC cells.

Effect of butyrate on aromatase cytochrome P450 levels in HT29, DLD-1 and LoVo colon cancer cells

Epidemiological studies suggest that colonic production of butyrate and estrogen may be involved in human susceptibility to colorectal cancer (CRC). Estrone (E1) can be produced by the aromatase pathway during the conversion of androstenedione (A) to E1. Therefore, we studied the effect of sodium butyrate (NaBu) on the CYP19A1 transcript and protein levels and on the conversion of A to E1 in HT29, DLD-1 and LoVo CRC cells. We found that NaBu significantly downregulated CYP19A1 transcript and protein levels, a phenomenon that was associated with reduced conversion of A to E1 in HT29, DLD-1 and LoVo cells. Our studies demonstrated that, although butyrate exhibited a protective role in CRC development, this compound may reduce aromatase activity and the production of E1 in colon cancer cells.

HDAC modulation and cell death in the clinic

Histone acetyltransferases (HATs) and histone deacetylases (HDACs) are two opposing classes of enzymes, which finely regulate the balance of histone acetylation affecting chromatin packaging and gene expression. Imbalanced acetylation has been associated with carcinogenesis and cancer progression. In contrast to genetic mutations, epigenetic changes are potentially reversible. This implies that epigenetic alterations are amenable to pharmacological interventions. Accordingly, some epigenetic-based drugs (epidrugs) have been approved by the Food and Drug Administration (FDA) and the European Medicines Agency (EMA) for cancer treatment. Here, we focus on the biological features of HDAC inhibitors (HDACis), analyzing the mechanism(s) of action and their current use in clinical practice.