Mitochondrial DNA mutation m.3243A>G is associated with altered mitochondrial function in peripheral blood mononuclear cells, with heteroplasmy levels and with clinical phenotypes

AIMS

To investigate the associations among heteroplasmy levels (i.e. the proportions of mutant and wild-type mitochondrial DNA in the same cell), mitochondrial function and clinical severity of the m.3243A>G mutation.

METHODS

A total of 17 participants carrying the m.3243A>G mutation and 17 sex- and age-matched healthy controls were included in this study. Heteroplasmy levels of the m.3243A>G mutation in leukocytes, saliva and urine sediment were determined by pyrosequencing. The clinical evaluation included endocrinological, audiological and ophthalmological examinations. Mitochondrial function was determined in peripheral blood mononuclear cells isolated from participants.

RESULTS

Heteroplasmy levels in urine sediment were higher than those in leukocytes and saliva. Reduced levels of adenosine triphosphate and mitochondrial membrane potential, and increased reactive oxygen species production were observed in mutant peripheral blood mononuclear cells (all P < 0.05). Linear regression analysis indicated that higher heteroplasmy levels in peripheral blood leukocytes were associated with increased levels of glycated albumin and HbA_1c , and decreased total hip bone mineral density T-score after adjustment for age and sex (all P < 0.05). Furthermore, mitochondrial membrane potential was independently associated with bone mineral density T-score at the femoral neck (P < 0.05).

CONCLUSIONS

Heteroplasmy levels in peripheral blood leukocytes and mitochondrial membrane potential in peripheral blood mononuclear cells were closely associated with clinical manifestations and were valuable for evaluation of the clinical severity of the m.3243A>G mutation.

Epididymal small non-coding RNA studies: progress over the past decade

BACKGROUND

Small non-coding RNAs (sncRNAs) accomplish a huge variety of biological functions. Over the past decade, we have witnessed the substantial progress in the epididymal sncRNA studies. In the Epididymis 7, we had the true privilege of having a whole session to share our findings and exchange ideas on the epididymal sncRNA studies.

OBJECTIVES

This mini-review attempts to provide an overview of what is known about the sncRNAs in the mammalian epididymis and discuss the future directions in this field.

METHODS

We surveyed literature regarding the sncRNA studies in the mammalian epididymis, and integrated some of our unpublished findings as well. We focus on the progress in methodology and the advances in our understanding of the expression and functions of epididymal sncRNAs.

RESULTS AND DISCUSSION

The applications of high-throughput approaches have made great contributions in the discovery of new sncRNA species and profiling their dynamics in the epithelial cells, the passing spermatozoa, and the luminal environment. The diverse classes of epididymal sncRNAs exert important biological functions from the in situ regulation of epididymal gene expression to the epigenetic inheritance in the offspring.

CONCLUSION

Although still in its infancy, we believe that the research on epididymal sncRNAs will not only lead to a better understanding of their physiological and pathological functions, but also contribute to the whole landscape of the RNA field.

Abstract P1-10-05: Analysis of genetic mutation in ethnically diverse population with Breast and ovarian cancer: Single institution experience

Only 5-10% of all breast and ovarian cancers have been attributed to inherited mutation. In unselected breast cancer patients, prevalence of germline BRCA 1 & 2 is about 2%. In Ashkenazi Jewish population the prevalence is estimated to be 11.7%. The rate of mutations in other populations has not been well characterized. The purpose of this study is to identify and characterize the risk of genetic mutations in an ethnically diverse population referred for genetic testing according to NCCN guidelines.

Method:

In this single institution retrospective study, we analyzed 782 patients referred for genetic testing between 2009-2018. Information regarding reason for referral, ethnicity, cancer history and results of genetic mutation using multigene panels were collected.

Results:

Reasons for referral were:

· Family History of cancer (142; 18.6%),

· Breast cancer diagnosed at early age (207; 26.4%),

· Triple negative breast cancer (12 ;53%

· Ovarian cancer (61; 7.8%)

· Multiple cancer (32; 4.09%)

· Known BRCA 1 or 2 mutation (51;6.5%)

· Known other mutation (9;1.15%)

· Family h/o cancer but not diagnosed with cancer (268)

Ethnic distribution:

· 328 Hispanic (41.94%)

· 177 Caucasian (22.6%),

· 27 Chinese, (3.4%)

· 52 Vietnamese (6.6%)

· 86 other- Asian (11%)

· 32 Middle eastern (4.1%),

· 14 South Asian (1.8%)

· 35 African American (4.5%)

· 8 Ashkenazi Jewish (1%)

· 19 Mixed Hispanic (2.1%)

Genetic testing was done in 545 /782 patients.

Deleterious Mutation detected: 88 patients (16.5% of tested)

· BRCA 1: 32(5.8%)

· BRCA 2:28 (5.14%)

· MSH2:5(0.9%)

· p53:39 (0.5%)

· PLB2:3 (0.38%)

· MUTYH:3 (0.38%)

· CDH1 :2 (0.26%)

· PMS2: 2 ( 0.26%)

· ATM: 1(0.13%)

· CCKn2A: 1(0.13%)

· CHEK 2: 1(0.13)

· MET:1(0.13%)

· MSH6:1 (0.13%)

· RAD50 :1(0.13%)

· RET1;1(0.13%)

BRCA1/BRCA2 mutation: 60

Mutation in BRCA 1/ 2 distribution by ethnicity:

· Hispanic (28; 8.54 %),

· Chinese (4;14.8%)

· Vietnamese (4; 7.7%)

· other Asian (12;13.9%)

· African American (3, 8.5, %)

· South Asian (0 %)

· Caucasian (8; 4.5 %)

· All Asian (20/165: 12.1%)

Mutation in other gene by Ethnicity: total 26

Hispanic (16, 4.5%), Caucasian: (3, 1.7%) Asian other than Chinese and Vietnamese (4, 4.65%)

Mutation in Breast cancer: 333 Breast cancer patients tested, 39 patients (11.17%) were found to have mutations.

10/32 triple negative (31%) 4/49 her2neu positive patients (8.1%) and 15/252 (5.9%) ER+ patients found to have mutations.

17/39 breast cancer patients with mutation had prophylactic BSO.

Mutation in BRCA 1& 2 by reason for referral:

Known family h/o of BRCA1 or 2 mutations (18; 39.5%)

Early age of cancer (10, 7.4%)

Cancer with positive family history (17, 8.2%)

Triple negative (2, 16%).

Variant of Unknown significance (VUS): 140 patients (25 %)

VUS in BRCA 2 were most common. VUS were found in 17% of Hispanic and African American patients.

No significant difference in PFS and OS was found in patient with mutation and without mutation

Conclusion:

We found much higher rates (16.5%) than previously reported mutation detection in this very highly diverse patient population.

Rate of BRCA 1&2 mutation was 8.55% in Hispanic and 12.1% in Asian patients compared with 4.5% in Caucasian patient when selected for high risk factors.

We Also noted very high rate of VUS especially in Hispanic and African American patients.

Citation Format: Aggarwal S, Chu C, Ngumi M. Analysis of genetic mutation in ethnically diverse population with Breast and ovarian cancer: Single institution experience [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-10-05.

LINC01510 suppresses cell proliferation and invasion by inhibiting Wnt/β-catenin signaling in renal cell carcinoma

The role of long non-coding RNA in Renal cell carcinoma (RCC) tumorigenesis and progression remains largely unknown. Here, we found that LINC01510 functions as a tumor suppressor in RCC tumorigenesis. We screened TCGA database and then found that LINC01510 is significantly down-regulated in malignant RCC tissues, and the lower expression of LINC01510 predicts poor prognosis. Moreover, the down-regulated LINC01510 was further confirmed in our fresh tissues and cell lines. Biological functions assays shown that Ectopic expression of LINC01510 not only inhibits RCC cell proliferation both in vitro and in vivo, but also impairs cell invasion ability. Moreover, we found overexpression of LINC01510 inhibits the expression of CCND1 and CCNE1, as well as MMPs (MMP2, MMP7 and MMP9), and thus affecting RCC cell cycle and invasion. Meanwhile, Western blot assays revealed that the expression of β-catenin is regulated by LINC01510; overexpression of β-catenin could partly rescue the cell viability and invasion ability caused by ectopic expression of LINC01510. Taken together, we found that LINC01510 regulates cell proliferation and invasion by modulating Wnt/β-catenin signaling in RCC.

Correlation of VEGF and EGFR in peripheral blood with clinical stage and pathological grade of renal cell carcinoma and analysis of prognosis

PURPOSE

To detect the expression of VEGF and EGFR in peripheral blood and cancer tissues of patients with renal cell carcinoma (RCC), and to explore the correlations with clinical stage, pathological grade and prognosis of disease.

METHODS

A total of 64 patients with RCC who were diagnosed and treated from June 2016 to August 2017 in our hospital were enrolled. Patients were divided into different clinical stages and pathological grades, and ELISA and immunohistochemistry were used to detect the expression of VEGF and EGFR in peripheral blood. Peripheral blood was also taken from 24 healthy individuals to serve as control group. Real-time fluorescence quantitative PCR (qRT-PCR) was used to detect the expression of VEGF and EGFR in RCC tissues and paracancer tissues. All patients were followed up after discharge to record their survival.

RESULTS

Significant differences in the expression levels of VEGF and EGFR were found between stage III and IV (p<0.05), but not between stage I and II. Expressions level of VEGF and EGFR in serum of well-differentiated, moderatelydifferentiated, and poorly-differentiated RCC were all higher than those in the healthy control group, and significant differences were found between different pathological grades (p<0.05). Patients with higher expression levels of VEGF and EGFR showed shorter survival compared to patients with lower expression levels (p<0.05).

CONCLUSION

VEGF and EGFR in peripheral blood can be used as one of the effective indicators of prognosis of RCC. Our study provided reference for clinical treatment and prediction of prognosis of RCC.

IRX3 is a genetic modifier for birth weight, adolescent obesity and transaminase metabolism

OBJECTIVE

IRX3 expression has been functionally associated in obesity-associated long-distance susceptibility loci, but the effect of the IRX3 genetic variants on human obesity and obesity-related metabolism remains uncertain.

METHODS

To determine the genetic role of IRX3, we conducted a molecular epidemiological analysis using three haplotype tagging single nucleotide polymorphisms (SNPs; rs8053360, rs3751723 and rs12445085) and one nonsynonymous SNP (rs1126960) at the IRX3 locus in 333 junior and senior high school students from a northeast Chinese population.

RESULTS

We identified significant associations between IRX3 SNPs and birth weight, body mass index (BMI), aspartate aminotransferase (AST), alanine aminotransferase (ALT) and AST/ALT ratio. The rs8053360 CC and rs1126960 GG genotypes were associated with increased birth weight and BMI, especially in females. Individuals with the rs12445085 TT genotype had significantly higher levels of AST and ALT, whereas individuals with the rs1126960 GG genotype had a significantly lower AST/ALT ratio than did individuals with other genotypes. However, no significant relationships were found between any of the IRX3 SNPs and metabolic syndrome or diabetes.

CONCLUSIONS

IRX3 genetic variants associate with birth weight, BMI and AST/ALT-related transaminase metabolism, supporting the role of IRX3 as an obesity-associated susceptibility gene.

Transcriptome analysis of primary aldosteronism in adrenal glands and controls

Primary aldosteronism (PA) is the most common form of endocrine hypertension. This study was to investigate the gene expression profile in PA adrenal glands and normal controls using RNA-Sequencing. By performing transcriptome analyses for 3 PA adrenal glands and 3 controls on Illumina platform, we identified 1,093 transcripts as significantly differently expressed genes (DEGs), which provided clues for further study of these transcript changes during PA pathogenesis. Further, Gene Set Enrichment Analysis (GSEA) identified 35 significant Kyoto Encyclopedia of Genes and Genomes (KEGG) biological pathways, including 'ribosome', 'oxidative phosphorylation', 'histidine metabolism', 'xenobiotics metabolism by Cytochrome P450', 'drug metabolism by Cytochrome P450', 'tyrosine metabolism' and 'glutathione metabolism'. In summary, we identified novel genes that are associated with PA phenotype, as well as differently regulated biological pathways relating to protein synthesis, energy acquisition and metabolism. Our study provides new candidates for further elucidation of the molecular mechanisms underlying PA pathogenesis.