Comparative effectiveness of sodium-glucose cotransporter-2 inhibitors for new-onset gastric cancer and gastric diseases in patients with type 2 diabetes mellitus: a population-based cohort study.

OBJECTIVE: To compare the risks of gastric cancer and other gastric diseases in patients with type-2 diabetes mellitus (T2DM) exposed to sodium-glucose cotransporter 2 inhibitors (SGLT2I), dipeptidyl peptidase-4 inhibitors (DPP4I) or glucagon-like peptide-1 receptor agonists (GLP1a). DESIGN: This was a population-based cohort study of prospectively collected data on patients with T2DM prescribed SGLT2I, DPP4I or GLP1a between January 1st 2015 and December 31st 2020 from Hong Kong. The outcomes were new-onset gastric cancer, peptic ulcer (PU), acute gastritis, non-acute gastritis, and gastroesophageal reflux disease (GERD). Propensity score matching (1:1) using the nearest neighbour search was performed, and multivariable Cox regression was applied. A three-arm comparison between SGLT2I, DPP4I and GLP1a was conducted using propensity scores with inverse probability of treatment weighting. RESULTS: A total of 62,858 patients (median age: 62.2 years old [SD: 12.8]; 55.93% males; SGLT2I: n = 23,442; DPP4I: n = 39,416) were included. In the matched cohort, the incidence of gastric cancer was lower in SGLT2I (Incidence rate per 1000 person-year, IR: 0.32; 95% confidence interval, CI 0.23-0.43) than in DPP4I (IR per 1000 person-year: 1.22; CI 1.03-1.42) users. Multivariable Cox regression found that SGLT2I use was associated with lower risks of gastric cancer (HR 0.30; 95% CI 0.19-0.48), PU, acute gastritis, non-acute gastritis, and GERD (p < 0.05) compared to DPP4I use. In the three-arm analysis, GLP1a use was associated with higher risks of gastric cancer and GERD compared to SGLT2I use. CONCLUSIONS: The use of SGLT2I was associated with lower risks of new-onset gastric cancer, PU, acute gastritis, non-acute gastritis, and GERD after matching and adjustments compared to DPP4I use. SGLT2I use was associated with lower risks of GERD and gastric cancer compared to GLP1a use.

Regulation of the human secretin gene is controlled by the combined effects of CpG methylation, Sp1/Sp3 ratio, and the E-box element.

To unravel the mechanisms that regulate the human secretin gene expression, in this study, we have used secretin-expressing (HuTu-80 cells, human duodenal adenocarcinoma) and non-secretin-expressing [PANC-1 (human pancreatic ductile carcinoma) and HepG2 (human hepatocellular carcinoma) cells] cell models for in vitro and in vivo analyses. By transient transfection assays, within the promoter region (-11 to -341 from ATG, relative to the ATG initiation codon), we have initially identified several functional motifs including an E-box and 2 GC-boxes. Results from gel mobility shift and chromatin immunoprecipitation assays confirmed further that NeuroD, E2A, Sp1, and Sp3 bind to these E- and GC-boxes in HuTu-80 cells in vitro and in vivo, whereas only high levels of Sp3 is observed to bind the promoter in HepG2 cells. In addition, overexpression of Sp3 resulted in a dose-dependent repression of the Sp1-mediated transactivation. Collectively, these data suggest that the Sp1/Sp3 ratio is instrumental to controlling secretin gene expression in secretin-producing and non-secretin-producing cells. The functions of GC-box and Sp proteins prompted us to investigate the possible involvement of DNA methylation in regulating this gene. Consistent with this idea, we found a putative CpG island (-336 to 262 from ATG) that overlaps with the human secretin gene promoter. By methylation-specific PCR, all the CpG dinucleo-tides (26 of them) within the CpG island in HuTu-80 cells are unmethylated, whereas all these sites are methylated in PANC-1 and HepG2 cells. The expressions of secretin in PANC-1 and HepG2 cells were subsequently found to be significantly activated by a demethylation agent, 5'-Aza-2' deoxycytidine. Taken together, our data indicate that the human secretin gene is controlled by the in vivo Sp1/Sp3 ratio and the methylation status of the promoter.

CpG methylation and transcription factors Sp1 and Sp3 regulate the expression of the human secretin receptor gene.

The human secretin receptor (hSR) is an important glycoprotein receptor for regulating the secretion of pancreatic bicarbonate, water, and electrolytes. In this study we investigated the transcriptional regulation of the hSR gene. A minimal 106-bp promoter was identified, and it contains two GC boxes (GC box-A, -240 to -226; and GC box-B, -203 to -194, from the translation start site). EMSA and supershift analyses showed that both GC boxes interact with Sp1 and Sp3 transcription factors. Transient transfection in pancreas-derived human pancreatic ductule carcinoma (PANC)-1 and bovine pancreatic duct-1 cells showed that mutation of either GC box-A or -B reduced the promoter strength by 56-67%, whereas mutation of both GC boxes caused more than 90% reduction of promoter activity. Cotransfections of the hSR promoter with Sp1 and Sp3 expression vectors in Sp-deficient Drosophila SL-2 Schneider cells further demonstrated that the ratio of Sp1 to Sp3 is the key mechanism to modulate hSR gene expression. The methylation statuses of 27 CpG sites within the promoter region (-400 to -151 bp) were assessed in various human pancreas and liver cell lines. The hSR promoter is unmethylated (CAPAN-1, human pancreatic adenocarcinoma) or partially methylated (PANC-1 and HPAC, human pancreatic adenocarcinoma) in hSR-expressing cell lines but is completely methylated in hSR nonexpressing HepG2 cells. Methyltransferase inhibitor 5-aza-2'deoxycytidine increased hSR gene expression level in PANC-1 cells and induced hSR gene expression in HepG2 cells. Together, our study shows that, in addition to Sp1 and Sp3, promoter methylation also plays a role in the regulation of hSR gene expression.

Identification of a potential receptor for both peptide histidine isoleucine and peptide histidine valine.

Peptide histidine isoleucine (PHI), peptide histidine valine (PHV), and vasoactive intestinal polypeptide (VIP) are cosynthesized from the same precursor and share high levels of structural similarities with overlapping biological functions. In this study, the first PHI/PHV receptor was isolated and characterized in goldfish. To study this receptor using homologous peptides, we have also characterized the goldfish prepro-PHI/VIP, and, surprisingly, a shorter transcript lacking the VIP coding region was isolated. A PHI/VIP precursor without the VIP coding sequence has never before been reported. Initial functional expression of the PHI/PHV receptor in Chinese hamster ovary cells revealed that it could be activated by human PHV [50% effective concentration (EC(50)): 43 nM] and to a lesser extent human PHI (EC(50): 133 nM) and helodermin (EC(50): 166 nM) but not fish and mammalian pituitary adenylate cyclase-activating polypeptides and VIPs. Subsequent studies indicated that, similar to the pituitary adenylate cyclase-activating polypeptide receptors (PAC1-R, VPAC1-R, and VPAC2-R), the receptor isolated in this study is able to interact with goldfish PHI and its C-terminally extended form, PHV with EC(50) values 93 and 43 nM, respectively. Northern blot and RT-PCR/Southern blot analyses revealed that the PHI/VIP gene is expressed in the intestine, brain, and gall bladder and the PHI/PHV receptor gene is primarily expressed in the pituitary and to a lesser extend in the intestine and gall bladder, suggesting that PHI/PHV may play a role, notably in the regulation of pituitary function. In conclusion, our results demonstrate for the first time the existence of a PHI/PHV receptor, indicating that the functions of PHI and PHV could be mediated by their own receptor in addition to VIP receptors.