Deregulated MicroRNAs in Biliary Tract Cancer: Functional Targets and Potential Biomarkers. Biomed Res Int. 2016;2016:4805270. [PMID: 27957497 PMCID: PMC5120202 DOI: 10.1155/2016/4805270]

Robust circulating microRNA signature for the diagnosis and early detection of pancreatobiliary cancer

BACKGROUND

A new circulating biomarker superior to carbohydrate antigen 19-9 (CA19-9) is needed for diagnosing pancreatobiliary cancer (PBca). The aim of this study was to identify serum microRNA (miRNA) signatures comprising reproducible and disease-related miRNAs.

METHODS

This multicenter study involved patients with treatment-naïve PBca and healthy participants. The optimized serum processing conditions were evaluated using t-distributed stochastic neighbor embedding (t-SNE) visualization. Serum miRNA candidates for disease association were selected using weighted gene coexpression network analysis (WGCNA). A miRNA signature combining multiple serum miRNAs was tested in exploratory, validation, and independent validation sets. The synthesis and secretion of diagnostic miRNAs were evaluated using human pancreatic cancer cells.

RESULTS

In total, 284 (150 healthy and 134 PBca) of 827 serum samples were processed within 2 h of blood collection before freezing, distributed in the same area as that in the t-SNE map, and assigned to an exploratory set. The 193 optimized samples were assigned to either the validation (50 healthy, 47 PBca) or independent validation (50 healthy, 46 PBca) set. Index-1, a combination of five serum miRNAs (hsa-miR-1343-5p, hsa-miR-4632-5p, hsa-miR-4665-5p, hsa-miR-665, and hsa-miR-6803-5p) with disease association in WGCNA, showed a sensitivity and specificity of > 80% and an AUC outperforming that of CA19-9 in the exploratory, validation, and independent validation sets. The AUC of Index-1 was superior to that of CA19-9 (0.856 vs. 0.649, p = 0.038) for detecting T1 tumors. miR-665, a component of Index-1, was expressed in human pancreatic cancer cells, and its transfection inhibited cell growth.

CONCLUSIONS

The serum miRNA signature Index-1 is useful for detecting PBca and could facilitate the early diagnosis of PBca. These findings can help improve clinical PBca detection by providing an optimized biomarker that overcomes the limitations of the current standard.

Prostate cancer therapy outcome prediction: are miRNAs a suitable guide for therapeutic decisions?

BACKGROUND

Radical prostatectomy, radiotherapy, chemotherapy, and androgen-deprivation therapy are among the most common treatment options for different forms of prostate cancer (PCa). However, making therapeutic decisions is difficult due to the lack of reliable prediction markers indicating therapy outcomes in clinical practice. The involvement of miRNAs in all mechanisms of the PCa development and their easy detection characterize them as attractive PCa biomarkers. Although there are extensive data on the role of miRNAs in PCa therapy resistance and sensitivity development, the issues of whether they could be used as a guide for therapy choice and, if so, how we can progress toward this goal, remain unclear. Thus, generalizable reviews and studies which summarize, compare, and analyze data on miRNA involvement in responses to different types of PCa therapies are required.

OBJECTIVES

Data on the involvement of miRNAs in therapy responses, on the role of cross-miRNA expression in different therapies, and on miRNA targets were analyzed in order to determine the miRNA-related factors which can lend perspective to the future development of personalized predictors of PCa sensitivity/resistance to therapies.

MATERIALS AND METHODS

The data available on the miRNAs associated with different PCa therapies (resistance and sensitivity therapies) are summarized and analyzed in this study, including analyses using bioinformatics resources. Special attention was dedicated to the mechanisms of the development of therapy resistance.

RESULTS AND DISCUSSION

A comprehensive combined analysis of the current data revealed a panel of miRNAs that were shown to be most closely associated with the PCa therapy response and were found to regulate the genes involved in PCa development via cell proliferation regulation, epithelial-mesenchymal transition (EMT), apoptosis, cell-cycle progression, angiogenesis, metastasis and invasion regulation, androgen-independent development, and colony formation.

CONCLUSION

The selected miRNA-based panel has the potential to be a guide for therapeutic decision making in the effective treatment of PCa.

Ouabain at nanomolar concentrations is cytotoxic for biliary tract cancer cells

Biliary tract cancer is a deadly disease with limited therapeutic options. Ouabain is a well-known inhibitor of the pumping function of Na+/K+-ATPase, though there is evidence that low concentrations of ouabain lead to a reduction of cell viability of cancer cells independent of its inhibition of the pumping function of the Na+/K+-ATPase. Regarding the impact of ouabain on biliary tract cancer, no data is currently available. Therefore, we aimed for a first-time investigation of ouabain as a potential anti-neoplastic biliary tract cancer agent using comprehensive human biliary tract cancer in vitro models. We found that ouabain has a strong cell line-dependent cytotoxic effect with IC50 levels in the (low) nanomolar-range and that this effect was not associated with the mRNA expression levels of the Na+/K+-ATPase α, β and fxyd-subunits. Regarding the mode of cytotoxicity, we observed induction of apoptosis in biliary tract cancer cells upon treatment with ouabain. Interestingly, cytotoxic effects of ouabain at sub-saturating (< μM) levels were independent of cellular membrane depolarization and changes in intracellular sodium levels. Furthermore, using a 3D cell culture model, we found that ouabain disturbs spheroid growth and reduces the viability of biliary tract cancer cells within the tumor spheroids. In summary, our data suggest that ouabain possesses anti-biliary tract cancer potential at low μM-concentration in 2D and 3D in vitro biliary tract cancer models and encourage further detailed investigation.

Research progress of bile biomarkers and their immunoregulatory role in biliary tract cancers

Biliary tract cancers (BTCs), including cholangiocarcinoma and gallbladder carcinoma, originate from the biliary epithelium and have a poor prognosis. Surgery is the only choice for cure in the early stage of disease. However, most patients are diagnosed in the advanced stage and lose the chance for surgery. Early diagnosis could significantly improve the prognosis of patients. Bile has complex components and is in direct contact with biliary tract tumors. Bile components are closely related to the occurrence and development of biliary tract tumors and may be applied as biomarkers for BTCs. Meanwhile, arising evidence has confirmed the immunoregulatory role of bile components. In this review, we aim to summarize and discuss the relationship between bile components and biliary tract cancers and their ability as biomarkers for BTCs, highlighting the role of bile components in regulating immune response, and their promising application prospects.

The Key Role of microRNAs in Initiation and Progression of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the main type of primary liver malignancy and the fourth leading cause of cancer-related death worldwide. MicroRNAs (miRNAs), a type of non-coding RNA that regulates gene expression mainly on post-transcriptional level has a confirmed and important role in numerous biological process. By regulating specific target genes, miRNA can act as oncogene or tumor suppressor. Recent evidence has indicated that the deregulation of miR-NAs is closely associated with the clinical pathological features of HCC. However, the precise regulatory mechanism of each miRNA and its targets in HCC has yet to be illuminated. This study demonstrates that both oncogenic and tumor suppressive miRNAs are crucial in the formation and development of HCC. miRNAs influence biological behavior including proliferation, invasion, metastasis and apoptosis by targeting critical genes. Here, we summarize current knowledge about the expression profile and function of miRNAs in HCC and discuss the potential for miRNA-based therapy for HCC.

Methylation of Tumor Suppressive miRNAs in Plasma from Patients With Pancreaticobiliary Diseases

BACKGROUND/AIM

We previously reported the usefulness of aberrant methylation of tumor suppressive miRNAs in bile to discriminate pancreaticobiliary cancers (PBCs) from benign pancreaticobiliary diseases (BD). Here we performed a methylation analysis of plasma miRNAs to identify miRNAs specific for PBCs.

PATIENTS AND METHODS

Plasma was collected from 80 patients with pancreatic cancer (PC); 18 with biliary tract cancer (BTC) and 28 with BD. Sequences encoding 3 tumor suppressive miRNAs (miR-200a, -200b, and -1247) were PCR amplified and sequenced, and their methylation rates were determined.

RESULTS

The methylation rate of miR-1247 was significantly higher in patients with BTC than in those with BD, and tended to be higher in patients with PC than in those with BD. Furthermore, it was significantly higher in three patients with stages I/II BTC than in those with BD.

CONCLUSION

Methylation of miR-1247 in plasma may be useful to distinguish BTC from BD.

Non-Coding RNAs Regulate the Resistance to Anti-EGFR Therapy in Colorectal Cancer

Colorectal cancer (CRC) is the third prevalent cancer worldwide, the morbidity and mortality of which have been increasing in recent years. As molecular targeting agents, anti-epidermal growth factor receptor (EGFR) monoclonal antibodies (McAbs) have significantly increased the progression-free survival (PFS) and overall survival (OS) of metastatic CRC (mCRC) patients. Nevertheless, most patients are eventually resistant to anti-EGFR McAbs. With the intensive study of the mechanism of anti-EGFR drug resistance, a variety of biomarkers and pathways have been found to participate in CRC resistance to anti-EGFR therapy. More and more studies have implicated non-coding RNAs (ncRNAs) primarily including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), are widely involved in tumorigenesis and tumor progression. They function as essential regulators controlling the expression and function of oncogenes. Increasing data have shown ncRNAs affect the resistance of molecular targeted drugs in CRC including anti-EGFR McAbs. In this paper, we have reviewed the advance in mechanisms of ncRNAs in regulating anti-EGFR McAbs therapy resistance in CRC. It provides insight into exploring ncRNAs as new molecular targets and prognostic markers for CRC.

Chemoresistance and resistance to targeted therapies in biliary tract cancer: What have we learned?

INTRODUCTION

Biliary tract cancer (BTC), including intra- and extrahepatic cholangiocarcinoma and gallbladder cancer, is a rare and highly difficult to manage human malignancy. Besides late diagnosis and associated unresectability, frequently observed unresponsiveness towards and recurrence following chemotherapy or targeted therapy essentially contribute to the dismal prognosis of BTC patients.

AREAS COVERED

The review provides an update on individual mechanisms involved resistance of BTC towards conventional chemotherapy as well as targeted therapies. We review the distinct mechanisms of pharmacoresistance (MPRs) which have been defined in BTC cells on a molecular basis and examine the specific consequences for the various approaches of chemo-, targeted or immunomodulatory therapies.

EXPERT OPINION

Based on currently available experimental and clinical data, the present knowledge about these MPRs in BTCs are summarized. While some possible tactics for overcoming these mechanisms of resistance have been investigated, a BTC-specific and efficient approach based on comprehensive in vitro and in vivo experimental systems is not yet available. Additionally, a reliable monitoring of therapy-relevant cellular changes needs to be established which allows for choosing the optimal drug (combination) before and/or during pharmacological therapy.

Pathogenetic Role and Clinical Implications of Regulatory RNAs in Biliary Tract Cancer

Biliary tract cancer (BTC) is characterised by poor prognosis and low overall survival in patients. This is generally due to minimal understanding of its pathogenesis, late diagnosis and limited therapeutics in preventing or treating BTC patients. Non-coding RNA (ncRNA) are small RNAs (mRNA) that are not translated to proteins. ncRNAs were considered to be of no importance in the genome, but recent studies have shown they play essential roles in biology and oncology such as transcriptional repression and degradation, thus regulating mRNA transcriptomes. This has led to investigations into the role of ncRNAs in the pathogenesis of BTC, and their clinical implications. In this review, the mechanisms of action of ncRNA are discussed and the role of microRNAs in BTC is summarised. The scope of this review will be limited to miRNA as they have been shown to play the most significant roles in BTC progression. There is huge potential in miRNA-based biomarkers and therapeutics in BTC, but more studies, research and technological advancements are required before it can be translated into clinical practice for patients.

The role of extracellular vesicles in cholangiocarcinoma

Cholangiocarcinoma (CCA) is a rare tumor that arises from cholangiocytes, the epithelial cells of the bile duct. The tumor is characterized by insidious onset, high degree of malignancy, poor prognosis and high recurrence rate. Due to the lack of specific biomarkers, it is difficult to diagnose CCA early and evaluate prognosis. Extracellular vesicles (EVs), which include apoptotic bodies, microvesicles and exosomes, have emerged as having important roles in cell-to-cell communication in both normal physiology and pathological conditions. Some research has found that EVs play a crucial role in the occurrence and development of CCA. EVs can carry specific molecular substances such as nucleic acids and proteins, which have potential for the diagnosis and therapy of CCA. This article reviews the current knowledge on the role of EVs in CCA. We highlight EVs and their functions in the physiology and pathophysiology of CCA, and discuss their therapeutic potential and their role as biomarkers.

Increased expression of plasma hsa-miR-181a in male patients with heroin addiction use disorder

BACKGROUND

Drug addiction is an uncontrolled, chronic, and recurrent encephalopathy that presently lacks specific and characteristic biomarkers for diagnosis and treatment. As regulators of gene expression, microRNAs (miRNAs) are increasingly used for diagnostic and prognostic purposes in various disease states. Previous studies indicated that miRNAs play important roles in the development and progression of drug addictions, including addiction to methamphetamine, cocaine, alcohol, and heroin.

METHODS

We identified significant miRNAs using the microarray method and then validated the hsa-miR-181a expression levels in 53 heroin addiction patients and 49 normal controls using quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR). Finally, the potential associations between transcriptional levels in heroin addiction patients and their clinicopathological features were analyzed.

RESULTS

A total of 2006 miRNAs were differentially expressed between heroin addiction patients and normal controls. The top 10 up-regulated miRNAs in patients were hsa-miR-21a, hsa-miR-181a, hsa-miR-4459, hsa-miR-4430, hsa-miR-4306, hsa-miR-22-3P, hsa-miR-486-5P, hsa-miR-371b-5P, hsa-miR-92a-3P, and hsa-miR-5001-5P. The top 10 down-regulated miRNAs in patients were hsa-miR-3195, hsa-miR-4767, hsa-miR-3135b, hsa-miR-6087, hsa-miR-1181, hsa-miR-4785, hsa-miR-718, hsa-miR-3141, hsa-miR-652-5P, and hsa-miR-6126. The expression level of hsa-miR-181a in heroin addiction patients was significantly increased compared with that in normal controls (P < .001). The area under the receiver operating characteristic curve of hsa-miR-181a was 0.783, the sensitivity was 0.867, and the specificity was 0.551.

CONCLUSIONS

The increased expression of hsa-miR-181a in the plasma of heroin patients may be a consequence of the pathological process of heroin abuse. This study highlights the potential of hsa-miR-181a as a novel biomarker for the diagnosis of heroin addiction.

Differences between Well-Differentiated Neuroendocrine Tumors and Ductal Adenocarcinomas of the Pancreas Assessed by Multi-Omics Profiling

Most pancreatic neuroendocrine tumors (PNETs) are indolent, while pancreatic ductal adenocarcinomas (PDACs) are particularly aggressive. To elucidate the basis for this difference and to establish the biomarkers, by using the deep sequencing, we analyzed somatic variants across coding regions of 409 cancer genes and measured mRNA/miRNA expression in nine PNETs, eight PDACs, and four intestinal neuroendocrine tumors (INETs). There were 153 unique somatic variants considered pathogenic or likely pathogenic, found in 50, 57, and 24 genes in PDACs, PNETs, and INETs, respectively. Ten and 11 genes contained a pathogenic mutation in at least one sample of all tumor types and in PDACs and PNETs, respectively, while 28, 34, and 11 genes were found to be mutated exclusively in PDACs, PNETs, and INETs, respectively. The mRNA and miRNA transcriptomes of PDACs and NETs were distinct: from 54 to 1659 differentially expressed mRNAs and from 117 to 250 differentially expressed miRNAs exhibited high discrimination ability and resulted in models with an area under the receiver operating characteristics curve (AUC-ROC) >0.9 for both miRNA and mRNA. Given the miRNAs high stability, we proposed exploring that class of RNA as new pancreatic tumor biomarkers.

Bile-derived circulating extracellular miR-30d-5p and miR-92a-3p as potential biomarkers for cholangiocarcinoma

BACKGROUND

Cholangiocarcinoma (CCA) is from cholangiocytes, and therefore bile is a potentially rich source of biomarkers for CCA. The aim of the study was to identify and validate microRNAs (miRNAs) in bile samples that are differentially expressed between benign biliary disease (BBD) and CCA.

METHODS

Bile samples from 106 patients with obstructive biliary disease were allocated consecutively to a discovery set (10 patients with BBD and 11 with CCA) and then a validation set (48 patients with BBD and 37 with CCA). An miRNA microarray platform was used to screen 1209 miRNAs in the discovery set. Quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) was used to validate the profiling results in the discovery and validation sets. In addition, the levels of carbohydrate antigen 19-9 (CA19-9) and carcinoembryonic antigen (CEA) were determined from patient serum samples.

RESULTS

Microarray profiling showed that miR-30d-5p and miR-92a-3p were significantly upregulated in bile from the CCA group compared with those from the BBD group. qRT-PCR results indicated that the expression levels of miR-30d-5p and of miR-92a-3p were significantly upregulated in the CCA group compared to the BBD group, validating the miRNA microarray results. Pathway analysis suggested that putative target genes of miR-30d-5p and of miR-92a-3p were involved in CCA-associated signalling pathways, such as Hippo, Wnt, p53, MAPK, and EGFR. Receiver operating curve analysis revealed that the areas under the curve for bile miR-30d-5p, miR-92a-3p, serum CA19-9, and CEA were 0.730, 0.652, 0.675, and 0.603, respectively, and bile miR-30d-5p showed the best diagnostic performance with a sensitivity of 81.1% and a specificity of 60.5%.

CONCLUSIONS

The levels of extracellular miR-30d-5p and miR-92a-3p in bile were significantly higher in patients with CCA than those in patients with BBD. Bile-derived circulating extracellular miR-30d-5p and miR-92a-3p are potential biomarkers for discriminating CCA from BBD.

Benefit of second-line systemic chemotherapy for advanced biliary tract cancer: A propensity score analysis

Whether 2nd-line-chemotherapy (2LCTX) + best-supportive-care (BSC) benefits patients with advanced biliary tract cancer (aBTC) more than BSC alone is unclear. We therefore conducted a propensity-score-based comparative effectiveness analysis of overall survival (OS) outcomes in 80 patients with metastatic, recurrent, or inoperable aBTC, of whom 38 (48%) were treated with BSC + 2LCTX and 42 (52%) with BSC alone. After a median follow-up of 14.8 months and 49 deaths, the crude 6-, 12-, and 18-month Kaplan-Meier OS estimates were 77%, 53% and 23% in the BSC + 2LCTX group, and 29%, 21%, and 14% in patients in the BSC group (p = 0.0003; Hazard ratio (HR) = 0.36, 95%CI:0.20-0.64, p = 0.001). An inverse-probability-of-treatment-weighted (IPTW) analysis was conducted to rigorously account for the higher prevalence of favorable prognostic variables in the 2LCTX + BSC group. After IPTW-weighting, the favorable association between 2LCTX and OS prevailed (adjusted HR = 0.40, 95%CI: 0.17-0.95, p = 0.037). IPTW-weighted 6-, 12-, and 18-month OS estimates were 77%, 58% and 33% in the BSC + 2LCTX group, and 39%, 28% and 22% in the BSC group (p = 0.037). Moreover, the benefit of 2LCTX was consistent across several clinically-relevant subgroups. Within the limitations of an observational study, these findings support the concept that 2LCTX + BSC is associated with an OS benefit over BSC alone in aBTC.

Isolation of Extracellular RNA from Bile

The study of extracellular RNA has been recently reported as a tool for biomarker discovery. Extracellular vesicles can be isolated from different types of body fluids which contain protein, mRNA, and noncoding RNA. Extracellular RNA isolated from bile could be a useful tool for analyzing biliary tract diseases or cancer. Herein, we describe protocols based on modifications of commercially available kits for the collection, processing, and isolation of extracellular RNA from bile.

MiR-371a-3p Serum Levels Are Increased in Recurrence of Testicular Germ Cell Tumor Patients

Metastatic testicular germ cell tumors (TGCTs) are a potentially curable disease by administration of risk-adapted cytotoxic chemotherapy. Nevertheless, a disease-relapse after curative chemotherapy needs more intensive salvage chemotherapy and significantly worsens the prognosis of TGCT patients. Circulating tumor markers (β-subunit of human chorionic gonadotropin (β-HCG), alpha-Fetoprotein (AFP), and Lactate Dehydrogenase (LDH)) are frequently used for monitoring disease recurrence in TGCT patients, though they lack diagnostic sensitivity and specificity. Increasing evidence suggests that serum levels of stem cell-associated microRNAs (miR-371a-3p and miR-302/367 cluster) are outperforming the traditional tumor markers in terms of sensitivity to detect newly diagnosed TGCT patients. The aim of this study was to investigate whether these miRNAs are also informative in detection of disease recurrence in TGCT patients after curative first line therapy. For this purpose, we measured the serum levels of miR-371a-3p and miR-367 in 52 samples of ten TGCT patients at different time points during disease relapse and during salvage chemotherapy. In our study, miR-371a-3p levels in serum samples with proven disease recurrence were 13.65 fold higher than levels from the same patients without evidence of disease (p = 0.014). In contrast, miR-367 levels were not different in these patient groups (p = 0.985). In conclusion, miR-371a-3p is a sensitive and potentially novel biomarker for detecting disease relapse in TGCT patients. This promising biomarker should be investigated in further large prospective trials.

HDAC-Linked "Proliferative" miRNA Expression Pattern in Pancreatic Neuroendocrine Tumors

Epigenetic factors are essentially involved in carcinogenesis, tumor promotion, and chemoresistance. Two epigenetic key players are miRNAs and histone deacetylases (HDACs). As previously shown by own theoretical databank analysis, the crosstalk between miRNAs and HDACs is relevant in different human chronic diseases and cancerogenic pathways. We aimed to investigate a potential connection between the expression of a well-defined subset of "proliferation-associated" miRNAs and the expression of HDACs as well as clinical parameters in pancreatic neuroendocrine tumors (pNETs).

MATERIALS AND METHODS

Expression levels of miRNA132-3p, miRNA145-5p, miRNA183-5p, miRNA34a-5p, and miRNA449a in 57 pNETs resected between 1997 and 2015 were measured and linked to the immunohistochemical expression pattern of members of the four HDAC classes on human tissue microarrays. All pNET cases were clinically and pathologically characterized according to published guidelines. Correlation analysis revealed a significant association between expression of specific miRNAs and two members of the HDAC family (HDAC3 and HDAC4). Additionally, a linkage between miRNA expression and clinico-pathological parameters like grading, TNM-staging, and hormone activity was found. Moreover, overall and disease-free survival is statistically correlated with the expression of the investigated miRNAs. Overall, we demonstrated that specific miRNAs could be linked to HDAC expression in pNETs. Especially miRNA449a (associated with HDAC3/4) seems to play an important role in pNET proliferation and could be a potential prognostic factor for poor survival. These first data could help, to improve our knowledge of the complex interactions of the epigenetic drivers in pNETs for further therapeutic approaches.

The histone methyltransferase G9a: a new therapeutic target in biliary tract cancer

The histone methyltransferase G9a (EHMT2) is a key enzyme for dimethylation of lysine 9 at histone 3 (H3K9me2), a suppressive epigenetic mark. G9a is over-expressed in tumor cells and contributes to cancer aggressiveness. Biliary tract cancer (BTC) is a rare cancer with dismal prognosis due to a lack of effective therapies. Currently, there are no data on the role of G9a in BTC carcinogenesis. We analyzed G9a expression in n=68 BTC patient specimens and correlated the data with clinicopathological and survival data. Moreover, we measured G9a expression in a panel of BTC cell lines and evaluated the cytotoxic effect of G9a inhibition in BTC cells using established small-molecule G9a inhibitors. G9a was considerably expressed in about half of BTC cases and was significantly associated with grading and tumor size. Additionally, we observed significant differences of G9a expression between growth type and tumor localization groups. G9a expression diametrically correlated with Vimentin (positive) and E-Cadherin (negative) expression. Importantly, survival analysis revealed G9a as a significant prognostic factor of poor survival in patients with BTC. In BTC cells, G9a and H3K9me2 were detectable in a cell line-dependent manner on mRNA and/or protein level, respectively. Treatment of BTC cells with established small-molecule G9a inhibitors resulted in reduction of cell viability as well as reduced G9a and H3K9me2 protein levels. The present study strongly suggests that G9a contributes to BTC carcinogenesis and may represent a potential prognostic factor as well as a therapeutic target.

MicroRNAs在结直肠癌中的研究进展

结直肠癌在我国恶性肿瘤中的发病率较高, 且其死亡率居高不下. 目前, 越来越多的学者十分关注微小RNAs(microRNAs, miRNAs)与结直肠癌的关系. miRNAs是普遍存在于生物体内的一类小分子非编码RNA, miRNAs的异常表达与结直肠癌的发生和进展密切相关. miRNAs可以通过转录后基因调控的方式, 来影响肿瘤细胞的增殖、调亡以及对化疗的敏感性等. 在这里, 我们回顾了近年来关于miRNAs与结直肠癌的相关文献, 了解miRNAs在结直肠癌中的表达、结直肠癌化疗耐药以及其与预后的关系, 从而更好的了解结直肠癌进展的生物学过程, 有助于结直肠癌的诊断与治疗, 提高结直肠癌患者的预后.

Biliary tract cancer stem cells - translational options and challenges

Management of biliary tract cancer remains challenging. Tumors show high recurrence rates and therapeutic resistance, leading to dismal prognosis and short survival. The cancer stem cell model states that a tumor is a heterogeneous conglomerate of cells, in which a certain subpopulation of cells - the cancer stem cells - possesses stem cell properties. Cancer stem cells have high clinical relevance due to their potential contributions to development, progression and aggressiveness as well as recurrence and metastasis of malignant tumors. Consequently, reliable identification of as well as pharmacological intervention with cancer stem cells is an intensively investigated and promising research field. The involvement of cancer stem cells in biliary tract cancer is likely as a number of studies demonstrated their existence and the obvious clinical relevance of several established cancer stem cell markers in biliary tract cancer models and tissues. In the present article, we review and discuss the currently available literature addressing the role of putative cancer stem cells in biliary tract cancer as well as the connection between known contributors of biliary tract tumorigenesis such as oncogenic signaling pathways, micro-RNAs and the tumor microenvironment with cancer stem cells.