Exploring homologous recombination repair and base excision repair pathway genes for possible diagnostic markers in hematologic malignancies.

Hematologic malignancies (HMs) are a collection of malignant transformations, originating from the cells in the bone marrow and lymphoid organs. HMs comprise three main types; leukemia, lymphoma, and multiple myeloma. Globally, HMS accounts for approximately 10% of newly diagnosed cancer. DNA repair pathways defend the cells from recurrent DNA damage. Defective DNA repair mechanisms such as homologous recombination repair (HRR), nucleotide excision repair (NER), and base excision repair (BER) pathways may lead to genomic instability, which initiates HM progression and carcinogenesis. Expression deregulation of HRR, NER, and BER has been investigated in various malignancies. However, no studies have been reported to assess the differential expression of selected DNA repair genes combinedly in HMs. The present study was designed to assess the differential expression of HRR and BER pathway genes including RAD51, XRCC2, XRCC3, APEX1, FEN1, PARP1, and XRCC1 in blood cancer patients to highlight their significance as diagnostic/ prognostic marker in hematological malignancies. The study cohort comprised of 210 blood cancer patients along with an equal number of controls. For expression analysis, q-RT PCR was performed. DNA damage was measured in blood cancer patients and controls using the comet assay and LORD Q-assay. Data analysis showed significant downregulation of selected genes in blood cancer patients compared to healthy controls. To check the diagnostic value of selected genes, the Area under curve (AUC) was calculated and 0.879 AUC was observed for RAD51 (p < 0.0001) and 0.830 (p < 0.0001) for APEX1. Kaplan-Meier analysis showed that downregulation of RAD51 (p < 0.0001), XRCC3 (p < 0.02), and APEX1 (p < 0.0001) was found to be associated with a significant decrease in survival of blood cancer patients. Cox regression analysis showed that deregulation of RAD51 (p < 0.0001), XRCC2 (p < 0.02), XRCC3 (p < 0.003), and APEX1 (p < 0.00001) was found to be associated with the poor prognosis of blood cancer patients. Comet assay showed an increased number of comets in blood cancer patients compared to controls. These results are confirmed by performing the LORD q-assay and an increased frequency of lesions/Kb was observed in selected genes in cancer patients compared to controls. Our results showed significant downregulation of RAD51, XRCC2, XRCC3, APEX1, FEN1, PARP1, and XRCC1 genes with increased DNA damage in blood cancer patients. The findings of the current research suggested that deregulated expression of HRR and BER pathway genes can act as a diagnostic/prognostic marker in hematologic malignancies.

Dysregulated expression of microRNAs acts as prognostic and diagnostic biomarkers for glioma patients.

INTRODUCTION: MicroRNAs are regulatory non-coding RNAs, with their outstanding regulatory mechanism, that make them potential biomarker for disease detection and therapeutics. They play an important role in pathological state, such as cancer by acting as oncogenic microRNAs and tumor suppressor microRNAs. The expression of microRNA-206, microRNA-4477a, microRNA-4795-5p, microR-4796-3p, microRNA-451b, and microRNA-4311 has proven to be deregulated in different cancer studies. However, no comprehensive study has been reported yet regarding their role in glioma patients. AIM: The present study is designed to examine the expression profiling of microRNAs, such as microRNA-206, microRNA-4477a, microRNA-4795-5p, microR-4796-3p, microRNA-451b, and microRNA-4311 in glioma patients. Furthermore, the expression deregulation of selected microRNAs was correlated with oxidative stress and proliferation rate in glioma patients. METHODS: For this purpose, 153 glioma tissue samples and 200 brain tissues from epilepsy patients (taken as controls) were collected in the present study. Expression analysis of selected microRNAs was carried out on collected samples using real-time PCR (qPCR). Oxidative stress and proliferation rate were measured by estimation of 8OXOG level and Ki-67 using the ELISA and IHC. RESULTS: Our results showed significant deregulation of microRNA-206 (p < 0.0001), microRNA-4477a (p < 0.01), microRNA-4311 (p < 0.0001), microRNA-4795-5p (p < 0.0001), microRNA-4796-3p (p < 0.0001), and microRNA-451b (p < 0.0001) in glioma patients compared to controls. However, significant upregulation of 8OXOG level (p < 0.0001) and Ki-67 (p < 0.0001) was observed in glioma patients compared to controls. Kaplan-Meier analysis showed that deregulated expression of selected microRNAs was associated with significant decrease in survival of glioma patients. CONCLUSIONS: Our results demonstrated significant deregulation of selected microRNAs in glioma patients. This deregulated expression was found associated with significant increased risk of glioma and could be further developed as effective prognostic biomarker and therapeutic tool in said disease.

Oncometabolic role of mitochondrial sirtuins in glioma patients.

Mitochondrial sirtuins have diverse role specifically in aging, metabolism and cancer. In cancer, these sirtuins play dichotomous role as tumor suppressor and promoter. Previous studies have reported the involvement of sirtuins in different cancers. However, till now no study has been published with respect to mitochondrial sirtuins and glioma risks. Present study was purposed to figure out the expression level of mitochondrial sirtuins (SIRT3, SIRT4, SIRT5) and related genes (GDH, OGG1-2α, SOD1, SOD2, HIF1α and PARP1) in 153 glioma tissue samples and 200 brain tissue samples from epilepsy patients (taken as controls). To understand the role of selected situins in gliomagenesis, DNA damage was measured using the comet assay and oncometabolic role (oxidative stress level, ATP level and NAD level) was measured using the ELISA and quantitative PCR. Results analysis showed significant down-regulation of SIRT4 (p = 0.0337), SIRT5 (p<0.0001), GDH (p = 0.0305), OGG1-2α (p = 0.0001), SOD1 (p<0.0001) and SOD2 (p<0.0001) in glioma patients compared to controls. In case of SIRT3 (p = 0.0322), HIF1α (p = 0.0385) and PARP1 (p = 0.0203), significant up-regulation was observed. ROC curve analysis and cox regression analysis showed the good diagnostic and prognostic value of mitochondrial sirtuins in glioma patients. Oncometabolic rate assessment analysis showed significant increased ATP level (p<0.0001), NAD+ level [(NMNAT1 (p<0.0001), NMNAT3 (p<0.0001) and NAMPT (p<0.04)] and glutathione level (p<0.0001) in glioma patients compared to controls. Significant increased level of damage ((p<0.04) and decrease level of antioxidant enzymes include superoxide dismutase (SOD, p<0.0001), catalase (CAT, p<0.0001) and glutathione peroxidase (GPx, p<0.0001) was observed in patients compared to controls. Present study data suggest that variation in expression pattern of mitochondrial sirtuins and increased metabolic rate may have diagnostic and prognostic significance in glioma patients.