Impact of VEGF gene polymorphisms and haplotypes on radiation-induced late toxicity in prostate cancer patients

Haptoglobin polymorphism and prostate cancer mortality

Prostate cancer is a common malignancy in men worldwide and it is known that oxidative stress is a risk factor for cancer development. A common functional haptoglobin (Hp) polymorphism, originating from a duplication of a gene segment spanning over two exons, results in three distinct phenotypes with different anti-oxidative capacities: Hp1-1, Hp1-2, and Hp2-2. The aim of the study was to investigate the relationship between this Hp polymorphism and prostate cancer mortality. The study was performed on 690 patients with histologically confirmed prostate cancer, recruited between January 2004 and January 2007. Hp genotypes were determined by a TaqMan fluorogenic 5′-exonuclease assay. Hp1-1 was present in 76 (11%), Hp1-2 in 314 (45.5%), and Hp2-2 in 300 (43.5%) patients. During a median follow-up of 149 months, 251 (35.3%) patients died. Hp genotypes were not significantly associated with higher overall mortality (HR 1.10; 95% CI 0.91–1.33; p = 0.34). This remained similar in a multivariate analysis including age at diagnosis, androgen deprivation therapy, and risk group based on PSA level, GS, and T stage (HR 1.11; 95% CI 0.91–1.34; p = 0.30). We conclude that the common Hp polymorphism does not seem to be associated with overall mortality in prostate cancer patients.

Molecular Profiling for Predictors of Radiosensitivity in Patients with Breast or Head-and-Neck Cancer

Nearly half of all cancers are treated with radiotherapy alone or in combination with other treatments, where damage to normal tissues is a limiting factor for the treatment. Radiotherapy-induced adverse health effects, mostly of importance for cancer patients with long-term survival, may appear during or long time after finishing radiotherapy and depend on the patient’s radiosensitivity. Currently, there is no assay available that can reliably predict the individual’s response to radiotherapy. We profiled two study sets from breast (n = 29) and head-and-neck cancer patients (n = 74) that included radiosensitive patients and matched radioresistant controls.. We studied 55 single nucleotide polymorphisms (SNPs) in 33 genes by DNA genotyping and 130 circulating proteins by affinity-based plasma proteomics. In both study sets, we discovered several plasma proteins with the predictive power to find radiosensitive patients (adjusted p < 0.05) and validated the two most predictive proteins (THPO and STIM1) by sandwich immunoassays. By integrating genotypic and proteomic data into an analysis model, it was found that the proteins CHIT1, PDGFB, PNKD, RP2, SERPINC1, SLC4A, STIM1, and THPO, as well as the VEGFA gene variant rs69947, predicted radiosensitivity of our breast cancer (AUC = 0.76) and head-and-neck cancer (AUC = 0.89) patients. In conclusion, circulating proteins and a SNP variant of VEGFA suggest that processes such as vascular growth capacity, immune response, DNA repair and oxidative stress/hypoxia may be involved in an individual’s risk of experiencing radiation-induced toxicity.

An adenosine derivative (IFC-305) reduced the risk of radiation-induced intestinal toxicity in the treatment of colon cancer by suppressing the methylation of PPAR-r promoter

BACKGROUND

IFC-305, an adenosine derivative, has been proved to exert a therapeutic effect on radiation-induced intestinal toxicity in colon cancer (CC). The aim of the present study was to investigate the underlying molecular mechanism of protective role of IFC-305 in CC by modifying the methylation of peroxisome proliferator-activated receptor (PPAR)-r promoter.

METHOD

Peripheral blood and cancerous tissues samples were collected from the CC patients. Irradiation (IR) mice models were established in comparison with control mice accordingly. Bisulfite sequencing, real-time PCR, Western-blot analysis, immunohistochemistry (IHC) and hematoxylin eosin (HE) staining were performed upon both human and animal samples.

RESULT

The results upon the human CC samples demonstrated that the level of methylation of PPAR-r promoter in methylated patients was increased, while the risk of radiation-induced intestinal toxicity in methylated patients was also increased compared with unmethylated patients. Also, the PPAR-r mRNA/protein expression was lower in methylated patients compared with unmethylated patients, thus indicating the presence of PPAR-r promoter methylation repressed PPAR-r expression in vivo. Moreover, in the mice models, IFC-305 treatment partially alleviated radiation-induced toxicity in the columnar epithelia and tubular glands of IR mice, and villus height and the number/circumference of crypts were also increased while the relative number of inflammatory cells was decreased in IR + IFC-305 mice group compared with the control mice. Compared with the control group, the levels of PPAR-r mRNA/protein expression were significantly decreased in IR mice, while the presence of IFC-305 exerted therapeutic effect upon IR rats via elevating the PPAR-r mRNA/protein expression to a certain extent.

CONCLUSION

In this study, we demonstrated the relationship between PPAR-r promoter methylation and the risk of radiation-induced intestinal toxicity via studying the clinical samples collected from CC patients. And the study upon mice models suggested that the administration of IFC-305 could alleviate radiation-induced intestinal toxicity through decreasing the methylation of PPAR-r promoter and enhancing the expression of PPAR-r in IR mice.

Association between five polymorphisms in vascular endothelial growth factor gene and urinary bladder cancer risk: A systematic review and meta-analysis involving 6671 subjects

BACKGROUND

Vascular endothelial growth factor (VEGF) gene plays a key role in angiogenesis and tumor growth. The relationship between VEGF gene polymorphisms and bladder cancer (BCa) risk was studied extensively in recent years. However, the currently available results are controversial. To ascertain whether VEGF polymorphisms are associated with the susceptibility to BCa, we conducted this systematic review and meta-analysis.

MATERIALS AND METHODS

Relevant studies were collected systemically from PubMed, Medline, Embase, Web of Science databases and the Cochrane Library. Odds ratios (ORs) and 95% confidence intervals (CIs) were evaluated using random or fixed effects models by Stata statistical software. This systematic review protocol was registered at International prospective register of systematic reviews (PROSPERO) under number CRD42018099279.

RESULTS

A total of eight articles including twenty case-control studies with 3206 BCa cases and 3645 controls were enrolled for this meta-analysis. By pooling all eligible studies, we found that rs3025039, rs833052 and rs25648 polymorphisms were significantly associated with BCa risk. However, in subgroup analyses by stage, we identified a decreased association between the rs699947 A-allele and Muscle-invasive Bladder Cancer (MIBC) under allele contrast, homozygous and recessive genetic models (A vs C: OR = 0.76; AA vs CC: OR = 0.49, 95%CI = 0.27-0.90, I² = 0.0%, P = 0.021; AA vs CA + CC: OR = 0.60, 95%CI = 0.38-0.96, I² = 0.0%, P = 0.034). As to ethnicity subgroup analysis, rs699947 and rs3025039 polymorphisms were thought as a risk factor for BCa risk in Asian population, while a decreased association was revealed between rs699947 (C > A) A-allele and BCa risk in African population under dominant, recessive, homozygous, heterozygous and allele contrast genetic models. While for other polymorphisms, null results were found.

CONCLUSION

Our meta-analysis suggested that rs3025039 (C > T), rs833052 (C > A) and rs25648 (C > T) polymorphisms of VEGF gene increased susceptibility to BCa risk. And our study also demonstrated homozygous TT genotype in rs3025039, homozygous AA genotype in rs833052 and homozygous TT genotype in rs25648 were significantly relevant to elevated BCa risk. In the meanwhile, it is worth noting that rs699947 (C > A) A-allele should be thought as a protective factor for MIBC.

Relative telomere length and prostate cancer mortality

PURPOSE

Telomeres are essential for the maintenance of chromosomal integrity and telomere length has been associated with cancer risk and development. Aim of the present study was to analyze the prognostic value of leukocyte relative telomere (RTL) length in long-term prostate cancer (PCa) mortality.

METHODS

Blood samples of PCa patients were obtained before initiation of radiotherapy. RTL of peripheral blood leukocytes was determined by a quantitative polymerase chain reaction method in 533 patients with PCa. Main outcome was overall mortality.

RESULTS

During a median follow-up time of 149 months, 188 (35.3%) patients died. In a univariate Cox regression analysis, RTL quartiles (longer RTL) were significantly associated with higher overall mortality (hazard ration (HR) = 1.20; 95% confidence interval (CI): 1.05-1.36; p = 0.006). In a multivariate Cox regression model including age at diagnosis, androgen deprivation therapy, and risk group (based on PSA level, GS, and T stage), RTL quartiles remained a significant predictor of higher overall mortality (HR = 1.22; 95% CI: 1.07-1.39; p = 0.003).

CONCLUSIONS

Longer leukocyte RTL predicts higher overall mortality in patients with PCa.

BCL2 genotypes and prostate cancer survival

Purpose

The antiapoptotic B‑cell lymphoma 2 (BCL2) gene is a key player in cancer development and progression. A functional single-nucleotide polymorphism (c.-938C>A, rs2279115) in the inhibitory P2 BCL2 gene promoter has been associated with clinical outcomes in various types of cancer. Aim of the present study was to analyze the role of BCL2-938C>A genotypes in prostate cancer mortality.

Methods

The association between BCL2-938C>A (rs2279115) genotypes and prostate cancer outcome was studied within the prospective PROCAGENE study comprising 702 prostate cancer patients.

Results

During a median follow-up time of 92 months, 120 (17.1%) patients died. A univariate Cox regression model showed a significant association of the CC genotype with reduced cancer-specific survival (CSS; hazard ratio, HR, 2.13, 95% confidence interval, CI, 1.10–4.12; p = 0.024) and overall survival (OS; HR 2.34, 95% CI 1.58–3.47; p < 0.001). In a multivariate Cox regression model including age at diagnosis, risk group, and androgen deprivation therapy, the CC genotype remained a significant predictor of poor CSS (HR 2.05, 95% CI 1.05–3.99; p = 0.034) and OS (HR 2.25, 95% CI 1.51–3.36; p < 0.001).

Conclusion

This study provides evidence that the homozygous BCL2-938 CC genotype is associated with OS and C in prostate cancer patients.

High Energy Particle Radiation-associated Oncogenic Transformation in Normal Mice: Insight into the Connection between Activation of Oncotargets and Oncogene Addiction

Concerns on high-energy particle radiation-induced tumorigenic transformation of normal tissue in astronauts, and in cancer patients undergoing radiotherapy, emphasizes the significance of elucidating the mechanisms involved in radiogenic transformation processes. Mostly used genetically modified or tumor-prone models are less reliable in determining human health risk in space or protracted post-treatment normal tissue toxicity. Here, in wild type C57BL/6 mice, we related the deregulation of distinctive set of tissue-specific oncotargets in major organs upon ⁵⁶Fe (600 MeV/amu; 0.5 Gy/min; 0.8 Gy) particle radiation and compared the response with low LET γ-radiation (¹³⁷Cs; 0.5 Gy/min; 2 Gy). One of the novel findings is the ‘tissue-independent’ activation of TAL2 upon high-energy radiation, and thus qualifies TAL2 as a potential biomarker for particle and other qualities of radiation. Heightened expression of TAL2 gene transcript, which sustained over four weeks post-irradiation foster the concept of oncogene addiction signaling in radiogenic transformation. The positive/negative expression of other selected oncotargets that expresses tissue-dependent manner indicated their role as a secondary driving force that addresses the diversity of tissue-dependent characteristics of tumorigenesis. This study, while reporting novel findings on radiogenic transformation of normal tissue when exposed to particle radiation, it also provides a platform for further investigation into different radiation quality, LET and dose/dose rate effect in healthy organs.

Association between single-nucleotide polymorphisms in growth factor genes and quality of life in men with prostate cancer and the general population

PURPOSE

Improved survival for men with prostate cancer has led to increased attention to factors influencing quality of life (QOL). As protein levels of vascular endothelial growth factor (VEGF) and insulin-like growth factor 1 (IGF-1) have been reported to be associated with QOL in people with cancer, we sought to identify whether single-nucleotide polymorphisms (SNPs) of these genes were associated with QOL in men with prostate cancer.

METHODS

Multiple linear regression of two data sets (including approximately 750 men newly diagnosed with prostate cancer and 550 men from the general population) was used to investigate SNPs of VEGF and IGF-1 (10 SNPs in total) for associations with QOL (measured by the SF-36v2 health survey).

RESULTS

Men with prostate cancer who carried the minor 'T' allele for IGF-1 SNP rs35767 had higher mean Role-Physical scale scores (≥0.3 SD) compared to non-carriers (p < 0.05). While this association was not identified in men from the general population, one IGF-1 SNP rs7965399 was associated with higher mean Bodily Pain scale scores in men from the general population that was not found in men with prostate cancer. Men from the general population who carried the rare 'C' allele had higher mean Bodily Pain scale scores (≥0.3 SD) than non-carriers (p < 0.05).

CONCLUSIONS

Through identifying SNPs that are associated with QOL in men with prostate cancer and men from the general population, this study adds to the mapping of complex interrelationships that influence QOL and suggests a role for IGF-I in physical QOL outcomes. Future research may identify biomarkers associated with increased risk of poor QOL that could assist in the provision of pre-emptive support for those identified at risk.

Single-nucleotide polymorphisms studied for associations with urinary toxicity from (125)I prostate brachytherapy implants

PURPOSE

To identify clinical, dosimetric, and genetic factors that are associated with late urinary toxicity after a (125)I prostate brachytherapy implant.

METHODS AND MATERIALS

Genomic DNA from 296 men treated with (125)I prostate brachytherapy monotherapy was extracted from saliva samples for this study. A retrospective database was compiled including clinical, dosimetric, and toxicity data for this cohort of patients. Fourteen candidate single-nucleotide polymorphism (SNPs) from 13 genes (TP53, ERCC2, GSTP1, NOS, TGFβ1, MSH6, RAD51, ATM, LIG4, XRCC1, XRCC3, GSTA1, and SOD2) were tested in this cohort for correlations with toxicity.

RESULTS

This study identified 217 men with at least 2 years of followup. Of these, 39 patients developed Grade ≥2 late urinary complications with a transurethral resection of prostate, urethral stricture, gross hematuria, or a sustained increase in their International Prostate Symptom Score. The only clinical or dosimetric factor that was associated with late urinary toxicity was age (p = 0.02). None of the 14 SNPs tested in this study were associated with late urinary toxicity in the univariate analysis.

CONCLUSIONS

This study identified age as the only variable being associated with late urinary toxicity. However, the small sample size and the candidate gene approach used in this study mean that further investigations are essential. Genome-wide association studies are emerging as the preferred approach for future radiogenomic studies to overcome the limitations from a candidate gene approach.

Polymorphism of VEGF-460C/T associated with the risk and clinical characteristics of lung cancer in Chinese population

Vascular endothelial growth factor (VEGF) is a major regulator of angiogenesis in the process of tumor growth and metastasis. Different VEGF gene polymorphisms have been shown to result in different VEGF protein expression in cancer cells and tumor angiogenic activity. We conducted a case-control study to evaluate the genetic effects of VEGF-460C/T polymorphism on the development of lung cancer. One hundred and twenty-six lung cancer patients and 160 sex-, age-, and ethnic-matched healthy controls were recruited for this study. The genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Odds ratios (ORs) and 95 % confidence intervals (CI) were calculated by logistic regression analysis. Our study showed that the TT genotype was associated with increased lung cancer risk than those with the CC (OR = 1.99, 95 % CI 1.05-3.77) or CT/CC (OR = 1.89, 95 % CI 1.17-3.06) genotype. Moreover, it was observed that the TT genotype associated with the advanced stage among lung cancer patients (TT vs. CC: OR = 3.09, 95 % CI 1.10-8.66). More studies are needed to detect VEGF-460C/T polymorphism and its association with lung cancer in different ethnic populations incorporated with environmental exposures.