MicroRNAs (miRNAs) are known as the master regulators of gene expression, and for the last two decades our knowledge of their functional reach keeps expanding. Recent studies have shown that a ...miRNA's role in regulation extends to extracellular and intracellular organelles. Several studies have shown a role for miRNA in regulating the mitochondrial genome in normal and disease conditions. Mitochondrial dysfunction occurs in many human pathologies, such as cardiovascular disease, diabetes, cancer, and neurological diseases. These studies have shed some light on regulation of the mitochondrial genome as well as helped to explain the role of miRNA in altering mitochondrial function and the ensuing effects on cells. Although the field has grown in recent years, many questions still remain. For example, little is known about how nuclear-encoded miRNAs translocate to the mitochondrial matrix. Knowledge of the mechanisms of miRNA transport into the mitochondrial matrix is likely to provide important insights into our understanding of disease pathophysiology and could represent new targets for therapeutic intervention. For this review, our focus will be on the role of a subset of miRNAs, known as MitomiR, in mitochondrial function. We also discuss the potential mechanisms used by these nuclear-encoded miRNAs for import into the mitochondrial compartment. Listen to this article's corresponding podcast at http://ajpheart.podbean.com/e/microrna-translocation-into-the-mitochondria/ .
MicroRNAs (miRNAs), one type of noncoding RNA, modulate post-transcriptional gene expression in various pathogenic pathways in type 2 diabetes (T2D). Currently, little is known about how miRNAs ...influence disease pathogenesis by targeting cells at a distance. The purpose of this study was to investigate the role of exosomal miRNAs during T2D.
We show that miR-15a is increased in the plasma of diabetic patients, correlating with disease severity. miR-15 plays an important role in insulin production in pancreatic β-cells. By culturing rat pancreatic β-cells (INS-1) cells in high-glucose media, we identified a source of increased miR-15a in the blood as exosomes secreted by pancreatic β-cells. We postulate that miR-15a, produced in pancreatic β-cells, can enter the bloodstream and contribute to retinal injury. miR-15a overexpression in Müller cells can be induced by exposing Müller cells to exosomes derived from INS-1 cells under high-glucose conditions and results in oxidative stress by targeting Akt3, which leads to apoptotic cell death. The in vivo relevance of these findings is supported by results from high-fat diet and pancreatic β-cell-specific miR-15a
mice.
This study highlights an important and underappreciated mechanism of remote cell-cell communication (exosomal transfer of miRNA) and its influence on the development of T2D complications.
Our findings suggest that circulating miR-15a contributes to the pathogenesis of diabetes and supports the concept that miRNAs released by one cell type can travel through the circulation and play a role in disease progression via their transfer to different cell types, inducing oxidative stress and cell injury. Antioxid. Redox Signal. 27, 913-930.
Molecular pathways in pancreatic carcinogenesis Macgregor-Das, Anne M.; Iacobuzio-Donahue, Christine A.
Journal of surgical oncology,
1 January 2013, Letnik:
107, Številka:
1
Journal Article
Genetic alterations of KRAS, CDKN2A, TP53, and SMAD4 are the most frequent events in pancreatic cancer. We determined the extent to which these 4 alterations are coexistent in the same carcinoma, and ...their impact on patient outcome.
Pancreatic cancer patients who underwent an autopsy were studied (n = 79). Matched primary and metastasis tissues were evaluated for intragenic mutations in KRAS, CDKN2A, and TP53 and immunolabeled for CDKN2A, TP53, and SMAD4 protein products. The number of altered driver genes in each carcinoma was correlated to clinicopathologic features. Kaplan-Meier estimates were used to determine median disease free and overall survival, and a Cox proportional hazards model used to compare risk factors.
The number of genetically altered driver genes in a carcinoma was variable, with only 29 patients (37%) having an alteration in all 4 genes analyzed. The number of altered driver genes was significantly correlated with disease free survival (P = 0.008), overall survival (P = 0.041), and metastatic burden at autopsy (P = 0.002). On multivariate analysis, the number of driver gene alterations in a pancreatic carcinoma remained independently associated with overall survival (P = 0.046). Carcinomas with only 1 to 2 driver alterations were enriched for those patients with the longest survival (median 23 months, range 1 to 53).
Determinations of the status of the 4 major driver genes in pancreatic cancer, and specifically the extent to which they are coexistent in an individual patients cancer, provides distinct information regarding disease progression and survival that is independent of clinical stage and treatment status.
Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy characterized by extensive local invasion and systemic spread. In this study, we employed a three-dimensional organoid model of ...human pancreatic cancer to characterize the molecular alterations critical for invasion. Time-lapse microscopy was used to observe invasion in organoids from 25 surgically resected human PDAC samples in collagen I. Subsequent lentiviral modification and small-molecule inhibitors were used to investigate the molecular programs underlying invasion in PDAC organoids. When cultured in collagen I, PDAC organoids exhibited two distinct, morphologically defined invasive phenotypes, mesenchymal and collective. Each individual PDAC gave rise to organoids with a predominant phenotype, and PDAC that generated organoids with predominantly mesenchymal invasion showed a worse prognosis. Collective invasion predominated in organoids from cancers with somatic mutations in the driver gene
(or its signaling partner
). Reexpression of SMAD4 abrogated the collective invasion phenotype in
-mutant PDAC organoids, indicating that SMAD4 loss is required for collective invasion in PDAC organoids. Surprisingly, invasion in passaged
-mutant PDAC organoids required exogenous TGFβ, suggesting that invasion in
-mutant organoids is mediated through noncanonical TGFβ signaling. The Rho-like GTPases RAC1 and CDC42 acted as potential mediators of TGFβ-stimulated invasion in
-mutant PDAC organoids, as inhibition of these GTPases suppressed collective invasion in our model. These data suggest that PDAC utilizes different invasion programs depending on
status, with collective invasion uniquely present in PDAC with SMAD4 loss. SIGNIFICANCE: Organoid models of PDAC highlight the importance of SMAD4 loss in invasion, demonstrating that invasion programs in
-mutant and
wild-type tumors are different in both morphology and molecular mechanism.
To evaluate whether germline variants in genes encoding pancreatic secretory enzymes contribute to pancreatic cancer susceptibility, we sequenced the coding regions of CPB1 and other genes encoding ...pancreatic secretory enzymes and known pancreatitis susceptibility genes (PRSS1, CPA1, CTRC, and SPINK1) in a hospital series of pancreatic cancer cases and controls. Variants in CPB1, CPA1 (encoding carboxypeptidase B1 and A1), and CTRC were evaluated in a second set of cases with familial pancreatic cancer and controls. More deleterious CPB1 variants, defined as having impaired protein secretion and induction of endoplasmic reticulum (ER) stress in transfected HEK 293T cells, were found in the hospital series of pancreatic cancer cases (5/986, 0.5%) than in controls (0/1,045, P = 0.027). Among familial pancreatic cancer cases, ER stress-inducing CPB1 variants were found in 4 of 593 (0.67%) vs. 0 of 967 additional controls (P = 0.020), with a combined prevalence in pancreatic cancer cases of 9/1,579 vs. 0/2,012 controls (P < 0.01). More ER stress-inducing CPA1 variants were also found in the combined set of hospital and familial cases with pancreatic cancer than in controls 7/1,546 vs. 1/2,012; P = 0.025; odds ratio, 9.36 (95% CI, 1.15–76.02). Overall, 16 (1%) of 1,579 pancreatic cancer cases had an ER stress-inducing CPA1 or CPB1 variant, compared with 1 of 2,068 controls (P < 0.00001). No other candidate genes had statistically significant differences in variant prevalence between cases and controls. Our study indicates ER stress-inducing variants in CPB1 and CPA1 are associated with pancreatic cancer susceptibility and implicate ER stress in pancreatic acinar cells in pancreatic cancer development.
TP53 and the TGFβ pathway are major mediators of pancreatic cancer metastasis. The mechanisms by which they cause hematogenous metastasis have not been fully explored.
(
;
;
) mice were generated, ...and the frequency and morphology of organ-specific hematogenous metastases compared with that seen in
and
littermates (
). Key findings were validated in primary cells from each genotype and samples of human pancreatic cancer liver metastases.
The frequency of hematogenous metastasis in
mice was significantly lower than for
mice (41% vs. 68%,
< 0.05), largely due to a reduction in liver metastases. No differences were found between
and
lung metastases, whereas liver metastases in
mice showed a profound extravasation deficiency characterized by sinusoidal growth and lack of desmoplastic stroma. Analogous findings were confirmed in liver samples from patients indicating their clinical relevance. Portal vein colonization as a direct mode of access to the liver was observed in both mice and humans. Secretome analyses of
cells revealed an abundance of secreted prometastatic mediators including Col6A1 and Lcn2 that promoted early steps of metastatic colonization. These mediators were overexpressed in primary tumors but not metastases, suggesting that the ability to colonize is, in part, developed within the primary site, a phenomenon we refer to as the "Cinderella effect."
These findings establish a novel paradigm for understanding pancreatic cancer metastasis and the observed clinical latencies of liver versus lung metastases specifically.
.
Correlative human studies suggest that the pleiotropic cytokine IL6 contributes to the development and/or progression of prostate cancer. However, the source of IL6 production in the prostate ...microenvironment in patients has yet to be determined. The cellular origin of IL6 in primary and metastatic prostate cancer was examined in formalin-fixed, paraffin-embedded tissues using a highly sensitive and specific chromogenic in situ hybridization (CISH) assay that underwent extensive analytical validation. Quantitative RT-PCR showed that benign prostate tissues often had higher expression of IL6 mRNA than matched tumor specimens. CISH analysis further indicated that both primary and metastatic prostate adenocarcinoma cells do not express IL6 mRNA. IL6 expression was highly heterogeneous across specimens and was nearly exclusively restricted to the prostate stromal compartment--including endothelial cells and macrophages, among other cell types. The number of IL6-expressing cells correlated positively with the presence of acute inflammation. In metastatic disease, tumor cells were negative in all lesions examined, and IL6 expression was restricted to endothelial cells within the vasculature of bone metastases. Finally, IL6 was not detected in any cells in soft tissue metastases. These data suggest that, in prostate cancer patients, paracrine rather than autocrine IL6 production is likely associated with any role for the cytokine in disease progression.
Abstract
Background: Interleukin-6 (IL-6) is a pleiotropic cytokine that elicits multiple physiological processes including immune responses, hematopoiesis, and cellular proliferation and ...differentiation. IL-6 has also been implicated in a number of pathophysiologic processes, including carcinogenesis. Multiple studies suggest that IL-6 may contribute to the development and/or progression of prostate cancer, and high systemic levels of IL-6 are associated with a more aggressive clinical course. A number of studies have indicated that prostatic adenocarcinoma cells express IL-6; yet, the source of IL-6 production in the prostate tumor microenvironment is debatable and it remains unclear if the cytokine acts in an autocrine or paracrine manner. Understanding the cellular origin of IL-6 is essential to establishing the mechanistic basis by which IL-6 may promote prostate cancer progression.
Methods: Quantitative PCR (qPCR) and chromogenic in situ hybridization (CISH) were used to study IL-6 expression in primary clinical prostatic carcinomas. As an initial approach, RNA derived from 11 prostate cell lines and 10 matched benign and tumor frozen prostate tissue samples were analyzed for IL-6 expression by qPCR. Next, formalin-fixed, paraffin embedded (FFPE) samples from the 11 cell lines, 21 prostatectomy samples, and 12 metastatic prostate cancer biopsy or autopsy tissue samples were analyzed by chromogenic in situ hybridization (CISH) for IL-6 mRNA (RNAscope, Advanced Cell Diagnostics, Inc.).
Results: Three of the prostate cell lines (PrSC, RWPE, DU145) were found to be positive for IL-6 expression by both qPCR and CISH, indicating complete concordance between the two assays. Surprisingly, qPCR analyses revealed that benign prostate tissues most often had higher expression of IL-6 than matched tumor. Subsequent IL-6 CISH analysis indicated that prostate adenocarcinoma cells do not express IL-6 mRNA in either primary or metastatic cancer cells; rather, IL-6 mRNA expression was nearly exclusively restricted to the prostate stromal compartment and was highly up-regulated in areas of acute inflammation and prostatic atrophy.
Conclusions: Our results are in contrast to published literature that argues that prostate cancer cells are the origin of IL-6 in the prostate tumor microenvironment and that prostate cancer progression is mediated by autocrine IL-6 signaling. The restriction of IL-6 expressing cells primarily to the prostate stromal compartment may alter the current understanding of how IL-6 may mediate the development and progression of prostate cancer.
Citation Format: Shu-Han Yu, Qizhi Zheng, Jun Luo, Anne Macgregor-Das, Emmanuel S. Antonarakis, Angelo M. De Marzo, Karen Sfanos. Interleukin-6 expression is restricted to the prostate stromal compartment and is not expressed by either primary or metastatic prostatic adenocarcinoma cells. abstract. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1648. doi:10.1158/1538-7445.AM2014-1648
Presently, the seroprevalence of human papillomavirus (HPV) minor capsid antigen L2-reactive antibody is not well understood, and no serologic standard exists for L2-specific neutralizing antibodies. ...Therefore, we screened a total of 1,078 serum samples for HPV16 L2 reactivity, and these were obtained from four prior clinical studies: a population-based (n = 880) surveillance study with a high-risk HPV DNA prevalence of 10.8%, a cohort study of women (n = 160) with high-grade cervical intraepithelial neoplasia (CIN), and two phase II trials in women with high-grade vulvar intraepithelial neoplasia (VIN) receiving imiquimod therapy combined with either photodynamic therapy (PDT) (n = 19) or vaccination with a fusion protein comprising HPV16 L2, E7, and E6 (TA-CIN) (n = 19). Sera were screened sequentially by HPV16 L2 enzyme-linked immunosorbent assay (ELISA) and then Western blot. Seven of the 1,078 serum samples tested had L2-specific antibodies, but none were detectably neutralizing for HPV16. To develop a standard, we substituted human IgG1 sequences into conserved regions of two rodent monoclonal antibodies (MAbs) specific for neutralizing epitopes at HPV16 L2 residues 17 to 36 and 58 to 64, creating JWW-1 and JWW-2, respectively. These chimeric MAbs retained neutralizing activity and together reacted with 33/34 clinically relevant HPV types tested. In conclusion, our inability to identify an HPV16 L2-specific neutralizing antibody response even in the sera of patients with active genital HPV disease suggests the subdominance of L2 protective epitopes and the value of the chimeric MAbs JWW-1 and JWW-2 as standards for immunoassays to measure L2-specific human antibodies.
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