Association of HSP70-hom genetic variant with prostate cancer risk

Association of genetic variants with prostate cancer in Africa: a concise review

Background

Prostate cancer (PCa) has one of the highest heritability of all major cancers, where the genetic contribution has been documented, and knowledge about the molecular genetics of the disease is increasing. However, the extent and aspects to which genetic variants explain PCa heritability in Africa are limited.

Main body

In this review, we summarize studies that highlight how identified genetic variants explain differences in PCa incidence and presentation across ethnic groups. We also present the knowledge gaps in PCa genetics in Africa and why Africa represents an untapped potential ground for genetic studies on PCa. A significant number of genome-wide association studies, linkage, and fine-mapping analyses have been conducted globally, and that explains 30–33% of PCa heritability. The African ancestry has a significant mention in PCa incidence and presentation. To date, the candidate gene approach has replicated 23 polymorphisms including dinucleotide and trinucleotide repeats in 16 genes. CYP17-rs743572, CYP3A4-rs2740574, CYP3A5-rs776746, CYP3A43-rs501275, and haplotype blocks, containing these variants, are significantly associated with PCa among some population groups but not others. With the few existing studies, the extent of genetic diversity in Africa suggests that genetic associations of PCa to African ancestry go beyond nucleotide sequence polymorphisms, to a level of environmental adaptation, which may interpret genetic risk profiles. Also, the shreds of evidence suggest that evolutionary history contributes to the high rates of PCa relative to African ancestry, and genetic associations do not always replicate across populations.

Conclusion

The genetic architecture of PCa in Africa provides important contributions to the global understanding of PCa specifically the African-ancestry hypothesis. There is a need for more prostate cancer consortiums to justify the heritable certainties of PCa among Africans, and emphasis should be placed on the genetic epidemiological model of PCa in Africa.

Prognostic Significance of the Hsp70 Gene Family in Colorectal Cancer

Background

Colorectal cancer (CRC) is a deadly form of cancer worldwide. Heat shock protein 70 (Hsp70) belongs to the family of human HSPs and plays an essential role in multiple cellular developments and in responding to environmental changes. However, studies on the relationship between CRC and the Hsp70 family are rare.

Material/Methods

Data pertaining to 438 patients with CRC was downloaded from The Cancer Genome Atlas database. To investigate the prognostic significance of the Hsp70 genes, survival and joint-effect analyses were conducted. The correlation between prognosis-related Hsp70 genes and clinical factors in CRC was analyzed using a nomogram. Gene set enrichment analysis (GSEA) was performed to explore the complex enrichment pathway in CRC with the prognosis-related Hsp70 genes.

Results

According to multivariate Cox regression survival analysis, low expression levels of HSPA1A, HSPA1B, and HSPA1L were correlated with improved overall survival (OS). According to the joint-effects survival analysis, the joint low expression levels of HSPA1A, HSPA1B, and HSPA1L were related to improved OS. The 1-, 3-, 5-, and 10-year survival rates of patients with CRC were predicted by constructing a nomogram model based on HSPA1A, HSPA1B, HSPA1L, and tumor stage. The GSEA results indicated the biological roles of HSPA1A, HSPA1B, and HSPA1L in CRC.

Conclusions

Low expression levels of HSPA1A, HSPA1B, and HSPA1L were strongly correlated with improved prognosis in CRC and might serve as latent prognostic biomarkers in CRC.

The differential neuroprotection of HSP70-hom gene single nucleotide polymorphisms: In vitro (neuronal hypoxic injury model) and in vivo (rat MCAO model) studies

To investigate the effect of HSP70-hom+2437 single nucleotide polymorphisms (SNPs) on hypoxia and ischemia condition, we constructed the neuronal hypoxic injury model and the rat middle cerebral artery occlusion (MCAO) model to compare the inhibition rate of neurons and detect the infarct volume as well as the expression of related apoptotic proteins in order to explore the possible mechanisms. The neuroblastoma cells SHSY5Y were divided into the OE (transfected with the C allele) group, OEmu (transfected with the T allele) group and negative control (NC, transfected with the empty lentiviral vector CON195) group. Varying degrees of hypoxia were induced by deferoxamine (DFO). The inhibition rate of hypoxic neurons and the expression of related apoptotic proteins were detected in the three genotype groups. While in the rat MCAO model, we built five groups including the sham group, the blank control group (injected with physiological saline), the negative control group (injected with lentivirus and physiological saline), the C allele group and the T allele group (injected with lentivirus overexpressing C and T allele). The MCAO model operation was then underwent in all five groups, the infarct volume by TTC staining and the expression of related apoptotic proteins were detected after 24 h. The results in neuronal hypoxic injury model showed a significant difference in the inhibition rate between the three groups (P < 0.05), and the average inhibition rates for the OEmu, OE and NC groups were 13.2%, 19.2% and 23.3%, respectively. The inhibition rates also differed between lower and higher DFO concentrations (P < 0.05). Compared with the NC group, Bax decreased significantly in the OE and OEmu groups, whereas PI3K and HSPA1L (HSP70-hom) increased. However, the expression of Bax in the OEmu group decreased significantly more than in the OE group, whereas PI3K and HSPA1L levels showed no difference between the two groups. Corresponding with the results above, overexpressing HSP70-hom could reduce the infarct volume of ischemic injury by TTC staining in rat MCAO model and the T allele group also had less infarct volume than C allele group. Compared with the sham group, blank control group and negative control group, Bax decreased significantly in the C and T allele groups, while HSPA1L and p- AKT increased. Furthermore, the expression of Bax in the T allele group decreased significantly more than that in the C allele group, while there were no significant differences in HSPA1L and p-AKT levels between the two groups. Therefore, the overexpression of HSP70-hom+2437 could play a protective role in hypoxic neurons and ischemic brain tissue by upregulating the expression of HSPA1L and PI3K/p-AKT and downregulating the expression of BAX. The neuroprotective effect of the T allele was stronger than that of the C allele, which may be related to the strengthened downregulation of BAX.

Interaction of heat shock protein 70 (HSP70) polymorphisms and occupational hazards increases the risk of hypertension in coke oven workers

OBJECTIVES

The interaction between genetic, epigenetic inheritance and environmental factors determines susceptibility to hypertension. Previous epidemiology studies have shown that coke oven workers who are frequently exposed to various occupational hazards have remarkable increase in the risk for hypertension. Among many genetic variants identified in hypertension, heat shock protein 70 (HSP70) was found to play important roles in the pathogenesis of hypertension and associated diseases. We therefore explore the possible role of HSP70 polymorphisms and their interaction with occupational environment in hypertension risk.

METHODS

We carried out a case-control study among 367 coke oven workers in northwest China, focused on three common HSP70 polymorphisms (HSP70-1 G190C, HSP70-2 A1267G and HSP70-hom T2437C), and evaluated the association of HSP70 gene polymorphisms with work sites for high risk of hypertension.

RESULTS

The results indicated that HSP70-1 GC and CC genotype had 2.73-fold and 4.26-fold increased relative risk (95% CI 1.33 to 5.55 and 1.17 to 15.53), respectively, comparing with HSP70-1 GG genotype. HSP70-2 AG and GG conferred a 47% and 36% reduced risk (95% CI 0.23 to 0.99 and 0.14 to 0.92) comparing with HSP70-2 AA genotype. Further analysis of the interaction of HSP70 polymorphisms with occupational environment indicated a strong positive interaction between HSP70 genotype (HSP70-1 GC+CC, HSP70-2 AA and HSP70-hom TC+CC) and oven top workplace.

CONCLUSIONS

Collectively, these data indicate that HSP70 polymorphisms interact with occupational hazards might increase the risk of hypertension in coke oven workers.

Study of single nucleotide polymorphisms of tumour necrosis factors and HSP genes in nasopharyngeal carcinoma in North East India

Nasopharyngeal carcinoma (NPC) is an epithelial tumour with a distinctive racial and geographical distribution. High incidence of NPC has been reported from China, Southeast Asia, and northeast (NE) region of India. The immune mechanism plays incredibly role in pathogenesis of NPC. Tumour necrosis factors (TNFs) and heat shock protein 70 (HSP 70) constitute significant components of innate as well as adaptive host immunity. Multi-analytical approaches including logistic regression (LR), classification and regression tree (CART) and multifactor dimensionality reduction (MDR) were applied in 120 NPC cases and 100 controls to explore high order interactions among TNF-α (-308 G>A), TNF β (+252 A>G), HSP 70-1 (+190 G>C), HSP 70-hom (+2437 T>C) genes and environmental risk factors. TNF β was identified as the primary etiological factor by all three analytical approaches. Individual analysis of results showed protective effect of TNF β GG genotype (adjusted odds ratio (OR2) = 0.27, 95 % CI = 0.125-0.611, P = 0.001), HSP 70 (+2437) CC genotype (OR2 = 0.17, 95 % CI = 0.0430.69, P = 0.013), while AG genotype of TNF β was found significantly associated with risk of NPC (OR2 = 1.97, 95 % CI = 1.019-3.83, P = 0.04). Analysis of environmental factors demonstrated association of alcohol consumption, living in mud houses and use of firewood for cooking as major risk factors for NPC. Individual haplotype association analysis showed significant risk associated with GTGA haplotype (OR = 68.61, 95 % CI = 2.47-190.37, P = 0.013) while a protective effect with CCAA and GCGA haplotypes (OR = 0.19, 95 % CI = 0.05-0.75, P = 0.019; OR = 0.01 95 % CI = 0.05-0.30, P = 0.007). The multi-analytical approaches applied in this study helped in identification of distinct gene-gene and gene-environment interactions significant in risk assessment of NPC.

Polymorphisms in genes coding for HSP-70 are associated with gastric cancer and duodenal ulcer in a population at high risk of gastric cancer in Costa Rica

BACKGROUND AND AIMS

Costa Rica has among the highest incidence and mortality rates for gastric cancer worldwide. The reasons for this are largely unknown. Polymorphisms of inflammatory response genes including genes encoding heat shock proteins (HSP) have been shown to be associated with the risk of gastric cancer in some populations. This study addresses the possible association between the HSP70-2 +1267 and HSP70-Hom +2437 polymorphisms and the risk of developing gastric cancer in a high-risk population in Costa Rica.

METHODS

DNA from 39 individuals diagnosed with gastric cancer, 79 healthy controls, 55 individuals with chronic gastritis and 52 individuals with duodenal ulcer was genotyped for the polymorphisms HSP70-2 +1267 and HSP70-Hom +2437 by RFLP. Logistic regression analysis was used to determine possible associations with the diagnoses and lineal regression analysis to determine associations with blood pepsinogen (PGs) levels as measured by serology.

RESULTS

The GA genotype of HSP70-2 was associated with increased risk of gastric cancer (OR = 3.42; 95% CI = 1.27-9.21; p = 0.015) and duodenal ulcer (OR = 2.57; 95% CI = 1.03-6.36; p = 0.042) as compared to the GG genotype. Persons with C carrier genotypes of HSP70-Hom were significantly less susceptible to gastric cancer than those with the TT genotype (OR = 0.29; 95% CI = 0.09-0.87; p = 0.027). The C carrier genotype was associated with lower PGI concentrations but none of the polymorphisms were associated with PGI/PGII.

CONCLUSIONS

Polymorphisms of HSP70 genes are associated with the development of gastric cancer and duodenal ulcers in a population at high risk for gastric cancer in Costa Rica.

Polymorphism of CAG repeats in androgen receptor of carnivores

Androgen effect is mediated by the androgen receptor (AR). The polymorphism of CAG triplet repeat (polyCAG), in the N-terminal transactivation domain of the AR protein, has been involved either in endocrine or neurological disorders in human. We obtained partial sequence of AR exon 1 in 10 carnivore species. In most carnivore species, polyglutamine length polymorphism presented in all three CAG repeat regions of AR, in contrast, only CAG-I site polymorphism presented in primate species, and CAG-I and CAG-III sites polymorphism presented in Canidae. Therefore, studies focusing on disease-associated polymorphism of poly(CAG) in carnivore species AR should investigate all three CAG repeats sites, and should not only consider CAG-I sites as the human disease studies. The trinucleotide repeat length in carnivore AR exon 1 had undergone from expansions to contractions during carnivores evolution, unlike a linear increase in primate species. Furthermore, the polymorphisms of the triplet-repeats in the same tissue (somatic mosaicism) were demonstrated in Moutain weasel, Eurasian lynx, Clouded leopard, Chinese tiger, Black leopard and Leopard AR. And, the abnormal stop codon was found in the exon 1 of three carnivore species AR (Moutain weasel, Eurasian lynx and Black leopard). It seemed to have a high frequency presence of tissue-specific somatic in carnivores AR genes. Thus the in vivo mechanism leading to such highly variable phenotypes of the described mutations, and their impact on these animals, are worthwhile to be further elucidated.

Heat shock proteins in prostate cancer: from tumorigenesis to the clinic

The heat shock proteins (HSP) constitute a superfamily of chaperone proteins present in all cells and in all cell compartments, operating in a complex interplay with synergistic/overlapping multiplicity of functions, even though the common effect is cell protection. Several reasons explain the need for investigating HSP in prostate cancer: (1) these molecules function as chaperones of tumorigenesis accompanying the emergence of prostate cancer cells, (2) they appear as useful molecular markers associated with disease aggressiveness and with resistance to anticancer therapies including hormone therapy, radiotherapy, chemotherapy and hyperthermia, and (3) they can be used as targets for therapies. The latter can be accomplished by: (i) interrupting the interaction of HSP (mainly HSPC1) with various client proteins that are protected from degradation when chaperoned by the HSP; (ii) using the chaperone and adjuvant capabilities of certain HSP to present antigenic peptides to the immune system, so this system can recognise the prostate tumour cells as foreign to mount an effective antitumoral response; and (iii) using treatment planning models taking into account the HSP expression levels to obtain more effective therapies. In summary, the study of the HSP during tumorigenesis as well as during cancer progression, and the inclusion of treatment designs targeting HSP combined with other treatment modalities, should improve prostate cancer survival in the near future.

Synergistic effect and VEGF/HSP70-hom haplotype analysis: relationship to prostate cancer risk and clinical outcome

Prostate cancer (PCa) is a complex disorder resulting from the combined effects of multiple environmental and genetic factors. Our previous single-locus analysis showed that VEGF and HSP70-hom polymorphisms were significantly associated with PCa susceptibility and prognosis. Both genes encoding these proteins were located on chromosome 6p21, and combining the neighboring single nucleotide polymorphisms (SNPs) into haplotypes may increase the association with the disease. Three tagging polymorphisms, the HSP70-hom 2437 T/C, the VEGF-1154 G/A, and the VEGF-634 G/C SNPs were genotyped in 101 cases and 80 controls. For the combined analysis of VEGF and HSP70-hom, we found a positive gradient in the odds ratios (ORs) related to the number of high-risk genotypes with a 3.53-fold increase of prostate carcinoma risk (OR = 3.53; p = 0.015). Furthermore, the TAG and CAG haplotypes at positions HSP70-hom, VEGF -1154 and VEGF -634 exhibited a two-fold (OR = 0.46; p = 0.014) and a seven-fold (OR = 0.14; p = 0.00005) reduction in PCa risk, respectively. Regarding PCa prognosis, the TAG haplotype had a negative association with the aggressive phenotype as defined by the histopathological grade (OR = 0.28; p = 0.006). Our findings confirm the role of at-risk haplotype across the HSP70-hom/VEGF gene cluster in determining susceptibility to PCa.

HSP70s: From Tumor Transformation to Cancer Therapy

Heat shock proteins (HSPs) are a defined set of chaperones for maintaining proper functions of proteins. The HSP70 family, one of the most inducible families in response to stress, protects cells from stress-induced cell death. It has been documented that HSP70s are highly expressed in various types of cancer cells and make the cells resistant to adverse microenvironments, such as hypoxia and glucose starvation, which are common features in malignant progression. Over-expression of HSP70s is thus associated with tumor transformation and eventually results in a decrease of chemotherapy efficacy. Notably, the distribution of HSP70s is deregulated in cancer cells. It has been reported that HSP70s localize distinct organelles or are exported to humoral circulation during cancer development. Either surface or exported HSP70s play danger signals and trigger immune response to destroy the tumor cells. In this review, we lay out recent advances in the HSP70s-mediated cancer diagnosis and therapy. This review would be enlightening for clinical cancer medicine.