Heme Oxygenase-1 Promoter Polymorphism is a Predictor of Disease Relapse in Pancreatic Neuroendocrine Tumors

Heme oxygenase 1 facilitates cell proliferation via the B-Raf-ERK signaling pathway in melanoma

BACKGROUND

Despite therapeutic advancements (e.g. B-RAF inhibitors) targeting cutaneous melanoma, many cellular processes, including inducible heme oxygenase 1 (HO-1), counteract treatments for malignancies. So there is an urgent need to find biological treatment targets, develop new therapeutic approaches and achieve longer responses. This study aimed to explore the relationship of HO-1 and B-Raf via mediating ERK1/2 signaling on cell cycle in melanoma.

METHODS

Immunohistochemistry was applied to evaluate the levels of HO-1 and B-Raf expression in melanoma tissues and adjacent healthy tissues. Co-immunoprecipitation (Co-IP) assessed the interaction of HO-1 with B-Raf. Further study overexpression and knock-down of HO-1 in A375 cell lines, especially knockout HO-1 using CRISPR-Cas9, verified HO-1 regulate cell proliferation in vivo and in vitro. Finally, Western blot analysis and qRT-PCR were performed to investigate the mechanisms by which HO-1 mediates cell cycle by B-RAF-ERK1/2 signaling.

RESULTS

First, histology and Co-IP show that HO-1 interacts with B-Raf directly in melanoma tissue. Further study illustrated that HO-1 overexpression promotes melanoma cell proliferation while HO-1 reduction represses melanoma cell proliferation because of HO-1 affects cell cycle. Mechanistic studies revealed that HO-1 was associated with a marked activation of B-RAF-ERK1/2 signaling and led to CDK2/cyclin E activation, thereby promoting melanoma proliferation.

CONCLUSIONS

Our result reveals a previously unknown mechanism that the HO-1-B-RAF-ERK axis plays an important role in melanoma cell proliferation. Therapeutic target on HO-1 could be a novel method for treating melanoma.

Association between GT-repeat polymorphism at heme oxygenase-1 gene promoter and gastric cancer and metastasis

HO-1 gene encodes heme oxygenase-1 enzyme that catalyzes the oxidation of heme to carbon monoxide (CO). It has also been suggested that cells could be protected by the enzyme against stress. A (GT) n dinucleotide repeat at HO-1 promoter is a polymorphic region and modulates gene transcription and associated with some of diseases. In this study, length of polymorphism GT tandem repeat has been determined and classified into two alleles short (≤28) and long (≥29). In present study, association between GT-repeat polymorphism at heme oxygenase-1 gene promoter and increased risk of gastric cancer and metastasis was investigated. Blood samples from 100 control individuals and 60 gastric cancer cases had taken. Genotypic frequencies of (GT) n repeat for samples were determined using PCR technique and polyacrylamide PAGE electrophoresis. At final, higher frequency alleles were sequenced. Our results show that S-allele is significantly higher in cases in comparison with control groups (p = 0/000, odds ratio (OR) = 4/154). It has been shown that individuals with S/S and S/L genotypes are at high risk of having gastric cancer (p = 0/000, OR = 3/789). Statistic data show association between SS genotype and risk of gastric cancer metastasis (p = 0.017, OR = 3.889). But, there is no significant association between clinicopathological characteristics of the patients and risk of gastric cancer metastasis (p > 0.05). Significant association was found between short allele (SS + SL genotypes) and risk of gastric cancer, and also strong association was found between SS genotype and risk of gastric cancer metastasis.

Capillary electrophoresis based on the nucleic acid detection in the application of cancer diagnosis and therapy

This review focuses on capillary electrophoresis-based nucleic acid detection as it is applied to cancer diagnosis and therapy, and provides an introduction to the drawbacks and future developments of analysis with CE.

GT microsatellite repeats in the heme oxygenase-1 gene promoter associated with abdominal aortic aneurysm in Croatian patients

Abdominal aortic aneurysm (AAA) is a complex genetic disorder caused by the interplay of genetic and environmental risk factors. The number of (GT)(n) repeats in the heme oxygenase-1 (HO-1) gene promoter modulates transcription of this enzyme, which might have anti-inflammatory, antioxidant, antiapoptotic, and antiproliferative effect. The distribution of alleles and genotypes in Croatian individuals genotyped for the (GT)(n) HO-1 polymorphism was similar to that in other European populations. Frequency of the short (S) alleles (GT < 25) was higher in AAA patients (41.9%) than in non-AAA individuals (28.2%, p = 0.0026) because there were more SL heterozygotes among the AAA patients. The SL genotype appeared to increase the risk for AAA, but the increase was not statistically significant after adjustment for age, sex, smoking, hypertension, and hyperlipidemia (OR = 1.53, 95% CI 0.90-3.09, p = 0.062). These findings contradict those of the only other study performed so far on the association of (GT)(n) HO-1 polymorphism and AAA.