MicroRNAs that affect prostate cancer: emphasis on prostate cancer in African Americans

Investigating miR-9 as a mediator in laryngeal cancer health disparities

Background

For several decades, Black patients have carried a higher burden of laryngeal cancer among all races. Even when accounting for sociodemographics, a disparity remains. Differentially expressed microRNAs have been linked to racially disparate clinical outcomes in breast and prostate cancers, yet an association in laryngeal cancer has not been addressed. In this study, we present our computational analysis of differentially expressed miRNAs in Black compared with White laryngeal cancer and further validate microRNA-9-5p (miR-9-5p) as a potential mediator of cancer phenotype and chemoresistance.

Methods

Bioinformatic analysis of 111 (92 Whites, 19 Black) laryngeal squamous cell carcinoma (LSCC) specimens from the TCGA revealed miRNAs were significantly differentially expressed in Black compared with White LSCC. We focused on miR-9-5 p which had a significant 4-fold lower expression in Black compared with White LSCC (p<0.05). After transient transfection with either miR-9 mimic or inhibitor in cell lines derived from Black (UM-SCC-12) or White LSCC patients (UM-SCC-10A), cellular migration and cell proliferation was assessed. Alterations in cisplatin sensitivity was evaluated in transient transfected cells via IC50 analysis. qPCR was performed on transfected cells to evaluate miR-9 targets and chemoresistance predictors, ABCC1 and MAP1B.

Results

Northern blot analysis revealed mature miR-9-5p was inherently lower in cell line UM-SCC-12 compared with UM-SCC-10A. UM -SCC-12 had baseline increase in cellular migration (p < 0.01), proliferation (p < 0.0001) and chemosensitivity (p < 0.01) compared to UM-SCC-10A. Increasing miR-9 in UM-SCC-12 cells resulted in decreased cellular migration (p < 0.05), decreased proliferation (p < 0.0001) and increased sensitivity to cisplatin (p < 0.001). Reducing miR-9 in UM-SCC-10A cells resulted in increased cellular migration (p < 0.05), increased proliferation (p < 0.05) and decreased sensitivity to cisplatin (p < 0.01). A significant inverse relationship in ABCC1 and MAP1B gene expression was observed when miR-9 levels were transiently elevated or reduced in either UM-SCC-12 or UM-SCC-10A cell lines, respectively, suggesting modulation by miR-9.

Conclusion

Collectively, these studies introduce differential miRNA expression in LSCC cancer health disparities and propose a role for low miR-9-5p as a mediator in LSCC tumorigenesis and chemoresistance.

Biological Aspects of Cancer Health Disparities

Racial and ethnic disparities span the continuum of cancer care and are driven by a complex interplay among social, psychosocial, lifestyle, environmental, health system, and biological determinants of health. Research is needed to identify these determinants of cancer health disparities and to develop interventions to achieve cancer health equity. Herein, we focus on the overall burden of ancestry-related molecular alterations, the functional significance of the alterations in hallmarks of cancer, and the implications of the alterations for precision oncology and immuno-oncology. In conclusion, we reflect on the importance of estimating ancestry, improving diverse racial and ethnic participation in cancer clinical trials, and examining the intersection among determinants of cancer health disparities.

Lung cancer health disparities

Compared with all other racial and ethnic groups in the United States, African Americans are disproportionally affected by lung cancer, both in terms of incidence and survival. It is likely that smoking, as the main etiological factor associated with lung cancer, contributes to these disparities, but the precise mechanism is still unclear. This paper seeks to explore the history of lung cancer disparities and review to the literature regarding the various factors that contribute to them.

MicroRNA-4719 and microRNA-6756-5p Correlate with Castration-Resistant Prostate Cancer Progression through Interleukin-24 Regulation

Prostate cancer (PCa) is the second leading cause of cancer death in the United States. The five-year survival rate for men diagnosed with localized PCa is nearly 100%, yet for those diagnosed with aggressive PCa, it is less than 30%. The pleiotropic cytokine Interleukin-24 (IL-24) has been shown to specifically kill PCa cells compared to normal cells when overexpressed in both in vitro and in vivo studies. Despite this, the mechanisms regulating IL-24 in PCa are not well understood. Since specific microRNAs (miRNAs) are dysregulated in PCa, we used miRNA target prediction algorithm tools to identify miR-4719 and miR-6556-5p as putative regulators of IL-24. This study elucidates the expression profile and role of miR-4719 and miR-6756-5p as regulators of IL-24 in PCa. qRT-PCR analysis shows miR-4719 and miR-6756-5p overexpression significantly decreases the expression of IL-24 in PCa cells compared to the negative control. Compared to the indolent PCa and normal prostate epithelial cells, miR-4719 and miR-6756-5p are significantly overexpressed in castration-resistant prostate cancer (CRPC) cell lines, indicating that their gain may be an early event in PCa progression. Moreover, miR-4719 and miR-6756-5p are significantly overexpressed in the CRPC cell line of African-American males (E006AA-hT) compared to CRPC cell lines of Caucasian males (PC-3 and DU-145), indicating that miR-4719 and miR-6756-5p may also play a role in racial disparity. Lastly, the inhibition of expression of miR-4719 and miR-6756-5p significantly increases IL-24 expression and inhibits proliferation and migration of CRPC cell lines. Our findings indicate that miR-4719 and miR-6756-5p may regulate CRPC progression through the targeting of IL-24 expression and may be biomarkers that differentiate between indolent and CRPC. Strategies to inhibit miR-4719 and miR-6756-5p expression to increase IL-24 in PCa may have therapeutic efficacy in aggressive PCa.

Nanoparticle-based targeted cancer strategies for non-invasive prostate cancer intervention

Prostate cancer is screened by testing circulating levels of the prostate-specific antigen (PSA) biomarker, monitoring changes over time, or a digital rectal exam. Abnormal results often lead to prostate biopsy. Prostate cancer positive patients are stratified into very low-risk, low-risk, intermediate-risk, and high-risk, based on clinical classification parameters, to assess therapy options. However, there remains a gap in our knowledge and a compelling need for improved risk stratification to inform clinical decisions and reduce both over-diagnosis and over-treatment. Further, current strategies for clinical intervention do not distinguish clinically aggressive prostate cancer from indolent disease. This mini-review takes advantage of a large number of functionally characterized microRNAs (miRNA), epigenetic regulators of prostate cancer, that define prostate cancer cell activity, tumor stage, and circulate as biomarkers to monitor disease progression. Nanoparticles provide an effective platform for targeted delivery of miRNA inhibitors or mimics specifically to prostate tumor cells to inhibit cancer progression. Several prostate-specific transmembrane proteins expressed at elevated levels in prostate tumors are under investigation for targeting therapeutic agents to prostate cancer cells. Given that prostate cancer progresses slowly, circulating miRNAs can be monitored to identify tumor progression in indolent disease, allowing identification of miRNAs for nanoparticle intervention before the crucial point of transition to aggressive disease. Here, we describe clinically significant and non-invasive intervention nanoparticle strategies being used in clinical trials for drug and nucleic acid delivery. The advantages of mesoporous silica-based nanoparticles and a number of candidate miRNAs for inhibition of prostate cancer are discussed.

The 22Rv1 prostate cancer cell line carries mixed genetic ancestry: Implications for prostate cancer health disparities research using pre-clinical models

BACKGROUND

Understanding how biological factors contribute to prostate cancer (PCa) health disparities requires mechanistic functional analysis of specific genes or pathways in pre-clinical cellular and animal models of this malignancy. The 22Rv1 human prostatic carcinoma cell line was originally derived from the parental CWR22R cell line. Although 22Rv1 has been well characterized and used in numerous mechanistic studies, no racial identifier has ever been disclosed for this cell line. In accordance with the need for racial diversity in cancer biospecimens and recent guidelines by the NIH on authentication of key biological resources, we sought to determine the ancestry of 22RV1 and authenticate previously reported racial identifications for four other PCa cell lines.

METHODS

We used 29 established Ancestry Informative Marker (AIM) single nucleotide polymorphisms (SNPs) to conduct DNA ancestry analysis and assign ancestral proportions to a panel of five PCa cell lines that included 22Rv1, PC3, DU145, MDA-PCa-2b, and RC-77T/E.

RESULTS

We found that 22Rv1 carries mixed genetic ancestry. The main ancestry proportions for this cell line were 0.41 West African (AFR) and 0.42 European (EUR). In addition, we verified the previously reported racial identifications for PC3 (0.73 EUR), DU145 (0.63 EUR), MDA-PCa-2b (0.73 AFR), and RC-77T/E (0.74 AFR) cell lines.

CONCLUSIONS

Considering the mortality disparities associated with PCa, which disproportionately affect African American men, there remains a burden on the scientific community to diversify the availability of biospecimens, including cell lines, for mechanistic studies on potential biological mediators of these disparities. This study is beneficial by identifying another PCa cell line that carries substantial AFR ancestry. This finding may also open the door to new perspectives on previously published studies using this cell line.

The clinical use of circulating microRNAs as non-invasive diagnostic biomarkers for lung cancers

Many studies have investigated the diagnostic role of circulating microRNAs (miRNAs) in patients with lung cancer; however, the results still remain inconclusive. An updated system review and meta-analysis was necessary to give a comprehensive evaluation of diagnostic role of circulating miRNAs in lung cancer. Eligible studies were searched in electronical databases. The sensitivity and specificity were used to plot the summary receiver operator characteristic (SROC) curve and calculate the area under the curve (AUC). The between-study heterogeneity was evaluated by Q test and I² statistics. Subgroup analyses and meta-regression were further performed to explore the potential sources of heterogeneity. A total of 134 studies from 65 articles (6,919 patients with lung cancer and 7,064 controls) were included for analysis. Overall analysis showed that circulating miRNAs had a good diagnostic performance in lung cancers, with a sensitivity of 0.83, a specificity of 0.84, and an AUC of 0.90. Subgroup analysis suggested that combined miRNAs and Caucasian populations may yield relatively higher diagnostic performance. In addition, we found serum might serve as an ideal material to detecting miRNA as good diagnostic performance. We also found the diagnostic role of miRNAs in early stage lung cancer was still relatively high (the sensitivity, specificity and an AUC of stage I/II was 0.81, 0.82 and 0.88; and for stage I, it was 0.80, 0.81, and 0.88). We also identified a panel of miRNAs such as miR-21-5p, miR-223-3p, miR-155-5p and miR-126-3p might serve as potential biomarkers for lung cancer. As a result, circulating miRNAs, particularly the combination of multiple miRNAs, may serve as promising biomarkers for the diagnosis of lung cancer.

The Genomic Impact of DNA CpG Methylation on Gene Expression; Relationships in Prostate Cancer

The process of DNA CpG methylation has been extensively investigated for over 50 years and revealed associations between changing methylation status of CpG islands and gene expression. As a result, DNA CpG methylation is implicated in the control of gene expression in developmental and homeostasis processes, as well as being a cancer-driver mechanism. The development of genome-wide technologies and sophisticated statistical analytical approaches has ushered in an era of widespread analyses, for example in the cancer arena, of the relationships between altered DNA CpG methylation, gene expression, and tumor status. The remarkable increase in the volume of such genomic data, for example, through investigators from the Cancer Genome Atlas (TCGA), has allowed dissection of the relationships between DNA CpG methylation density and distribution, gene expression, and tumor outcome. In this manner, it is now possible to test that the genome-wide correlations are measurable between changes in DNA CpG methylation and gene expression. Perhaps surprisingly is that these associations can only be detected for hundreds, but not thousands, of genes, and the direction of the correlations are both positive and negative. This, perhaps, suggests that CpG methylation events in cancer systems can act as disease drivers but the effects are possibly more restricted than suspected. Additionally, the positive and negative correlations suggest direct and indirect events and an incomplete understanding. Within the prostate cancer TCGA cohort, we examined the relationships between expression of genes that control DNA methylation, known targets of DNA methylation and tumor status. This revealed that genes that control the synthesis of S-adenosyl-l-methionine (SAM) associate with altered expression of DNA methylation targets in a subset of aggressive tumors.

miRNAs as drivers of TMPRSS2-ERG negative prostate tumors in African American men

African Americans (AAs) who have PCa typically have more aggressive disease and make up a disproportionate number of the disease deaths, relative to European Americans (EAs). TMPRSS2 translocations, a common event in EA patients, are exploited in diagnostic and prognostic settings, whereas they are diminished in frequency in AA men. Thus, these patients with TMPRSS2 fusion-negative disease represent an under-investigated patient group. We propose that epigenetic events are a significant and alternative driver of aggressive disease in fusion-negative PCa. To reveal epigenetically governed microRNAs (miRNAs) that are enriched in fusion-negative disease and associated with aggressive in AA PCa, we leveraged both our experimental evidence and publically available data. These analyses identified 18 miRNAs that are differentially altered in fusion-negative disease, associated with DNA CpG methylation, and implicated in aggressive and AA PCas. Understanding the relationships between miRNA expression, upstream epigenetic regulation by DNA methylation, and downstream regulation of mRNA targets in fusion negative disease is imperative to understanding the biological basis of the racial health disparity in PCa.

MicroRNA profiling of novel African American and Caucasian Prostate Cancer cell lines reveals a reciprocal regulatory relationship of miR-152 and DNA methyltranferase 1

miRNA expression in African American compared to Caucasian PCa patients has not been widely explored. Herein, we probed the miRNA expression profile of novel AA and CA derived prostate cancer cell lines. We found a unique miRNA signature associated with AA cell lines, independent of tumor status. Evaluation of the most differentially expressed miRNAs showed that miR-132, miR-367b, miR-410, and miR-152 were decreased in more aggressive cells, and this was reversed after treatment of the cells with 5-aza-2′-deoxycytidine. Sequencing of the miR-152 promoter confirmed that it was highly methylated. Ectopic expression of miR-152 resulted in decreased growth, migration, and invasion. Informatics analysis of a large patient cohort showed that decreased miR-152 expression correlated with increased metastasis and a decrease in biochemical recurrence free survival. Analysis of 39 prostate cancer tissues with matched controls (20 AA and 19 CA), showed that 50% of AA patients had statistically significant lower miR-152 expression compared to only 35% of CA patients. Ectopic expression of miR-152 in LNCaP, PC-3, and MDA-PCa-2b cells down-regulated DNA (cytosine-5)-methyltransferase 1 (DNMT1) through direct binding in the DNMT1 3'UTR. There appeared to be a reciprocal regulatory relationship of miR-152/DNMT1 expression, as cells treated with siRNA DNMT1 caused miR-152 to be re-expressed in all cell lines. In summary, these results demonstrate that epigenetic regulation of miR-152/DNMT1 may play an important role in multiple events that contribute to the aggressiveness of PCa tumors, with an emphasis on AA PCa patients.

Epithelial and stromal expression of miRNAs during prostate cancer progression

Global microRNA (miRNA) profile may predict prostate cancer (PCa) behaviors. In this study, we examined global miRNA expression by miRNA profiling as well as specific miRNA expression levels in PCa epithelium and stroma by in situ hybridization (ISH) and correlated with various clinicopathological features. We first performed comprehensive miRNA profiling on 27 macrodissected cases of PCa by miRNA microarray. A total of 299 miRNAs were significantly dysregulated in high grade and advanced stage PCa. We demonstrated that PCa can be readily classified into high grade/stage and low-grade/stage groups by its global miRNA expression profile. Next, we examined the expression of several selected dysregulated miRNAs, including let-7c, miR-21, miR-27a, miR-30c, and miR-219, in PCa by ISH. The levels of miRNA expression in epithelial and stromal cells were scored semiquantitatively and compared with clinicopathological features, including age, race, Gleason score, stage, PSA recurrence, metastasis, hormone resistance and survival. We found that the expression of miR-30c and miR-219 were significantly down-regulated in PCa. miR-21 and miR-30c were significantly down-regulated in PCa in African Americans compared to Caucasian Americans. In addition, down-regulation of let-7c, miR-21, miR-30c, and miR-219 are associated with metastatic disease. Furthermore, down-regulation of miR-30c and let-7c are significantly associated with androgen-dependent PCa. In PCa stromal cells, let-7c downregulation is significantly associated with extraprostatic extension. Our data suggest that selected miRNAs may serve as potential biomarkers to predict cancer progression.

Accomplishments of the Trustees and laboratory staff of the Biological Stain Commission, 2002-2013

During the 12 years from 2002 to 2013, the Trustees and laboratory personnel of the Biological Stain Commission (BSC) can claim many accomplishments. These accomplishments are itemized under 11 categories: continuous publication of the official journal, Biotechnic & Histochemistry; production of four special issues of Biotechnic & Histochemistry devoted to specific dyes or stains; standardization of staining and dye purity; mechanisms of staining and prediction of dye behavior; publication of books or book chapters; effects of fixation and processing on staining; cancer research; immunohistochemistry; BSC Laboratory activities; miscellaneous publications; and administrative accomplishments.

Exosomes: a novel pathway of local and distant intercellular communication that facilitates the growth and metastasis of neoplastic lesions

Normal and diseased cells release bilayered membrane-bound nanovesicles into interstitial spaces and into bodily fluids. A subgroup of such microvesicles is called exosomes and is described in blood as 30 to 100 nm in diameter and as spherical to cup-shaped nanoparticles with specific surface molecular characteristics (eg, expression of the tetraspanins CD9, CD81, and CD63). Extracellular microvesicles provide local signals (eg, autocrine and paracrine) and distant endocrine signals to cells via the transfer of their contents, which include signal proteins, lipids, miRNAs, and functional mRNAs. Exosomes and related microvesicles also aid cells in exporting less-needed molecules and potentially harmful molecules, including drugs; in the case of neoplasia, the export of chemotherapeutic drugs may facilitate cellular chemoresistance. Cancers have adapted the exosome and related microvesicles as a pathway by which neoplastic cells communicate with each other (autocrine) and with nonneoplastic cells (paracrine and endocrine); via this pathway, cancer suppresses the immune system and establishes a fertile local and distant environment to support neoplastic growth, invasion, and metastases. Because exosomes mirror and bind to the cells from which they arise, they can be used for delivery of drugs, vaccines, and gene therapy, as biomarkers and targets. We review how exosomes and related extracellular microvesicles facilitate the progression and metastases of cancers and describe how these microvesicles may affect clinical care.