Human HRH3 blocking peptide

We previously found that genetic polymorphisms in gene coding for histamine H-4 receptors were related to the risk and malignant degree of breast cancer. The roles of polymorphisms in other histamine-related genes, such as histidine decarboxylase (HDC), histamine N-methyltransferase (HNMT) and histamine H-3 receptor (HRH3), remain unexplored. The aim of this study is to analyze the clinical associations of polymorphisms in HDC, HNMT and HRH3 with breast cancer. Two hundred and one unrelated Chinese Han breast cancer patients and 205 ethnicity-matched health controls were recruited for case-control investigation. Genomic DNA from the participants was extracted and 5 single nucleotide polymorphisms (SNPs) in HDC, HNMT and HRH3 were genotyped. We found that polymorphisms of HNMT and HRH3 were irrelevant with breast cancer in the present study. However, the T allele of rs7164386 in HDC significantly decreased the risk of breast cancer (adjusted odds ratios [ORs], 0.387; 95% confidence intervals [CIs], 0.208-0.720; P = 0.003). Furthermore, for HDC haplotypes, the CG haplotype of rs7164386-rs7182203 was more frequent among breast cancer patients (adjusted OR, 1.828; 95% CI, 1.218-2.744; P = 0.004) while the TG haplotype was more frequent among health controls (adjusted OR, 0.351; 95% CI, 0.182-0.678; P = 0.002). These findings indicated that polymorphisms of HDC gene were significantly associated with breast cancer in Chinese Han population and may be novel diagnostic or therapeutic targets for breast cancer. Further studies with larger participants worldwide are still needed for conclusion validation.

Histamine receptor H3 (HRH3) is mainly expressed in the central nervous system, where it is involved in the regulation of the release of various neurotransmitters in the brain. Recent studies have demonstrated that the expression of HRH3 is upregulated in several types of cancer. However, the functional effect of HRH3 on tumor progression remains largely unknown, particularly in hepatocellular carcinoma (HCC). In the present study, the expression of HRH3 in 96 HCC patients was first evaluated, and its clinical significance was analyzed. Subsequently, the functional roles of HRH3 in HCC growth and metastasis were systematically explored in vitro and in vivo using its agonist (imetit) or antagonist (clobenpropit). It was observed that HRH3 was significantly upregulated in HCC tissues, while its expression was significantly associated with recurrence-free survival and overall survival in HCC patients. Functional experiments also demonstrated that HRH3 upregulation facilitated the growth and metastasis of HCC cells by inducing the formation of lamellipodia. These findings revealed that HRH3 serves an important role in the growth and metastasis of HCC cells, which provides experimental evidence supporting the application of HRH3 as a potential therapeutic target in HCC treatment.