miR-34a overexpression predicts poor prognostic outcome in colorectal adenocarcinoma, independently of clinicopathological factors with established prognostic value

Lower expressions of MIR34A and MIR31 in colo-rectal cancer are associated with an enriched immune microenvironment

INTRODUCTION

MicroRNAs (MIRs) play a crucial role in colorectal cancer (CRC) development and metastasis by regulating immune responses. Tumour-infiltrating lymphocytes (TILs) are an important predictive factor in many cancers, but, their association with microRNAs have not been studied well in colorectal cancer. Three microRNAs (MIR34A, MIR31 & MIR21), the roles of which in tumorigenesis is well-studied and which also possess immunomodulatory effect, were identified by extensive literature search. Of these, MIR34A acts as a tumour suppressor, MIR21 is considered an onco-MIR, and MIR31 displays both tumour-suppressing and oncogenic properties, making it ambiguous. This study examines the relationship between these three micro-RNAs and TILs in CRC.

MATERIALS & METHODS

Conducted over 18 months at a tertiary cancer care hospital in southern India, this unicentric observational study included 69 cases. These cases were analyzed for miR expression using q-RT-PCR, TILs density through hematoxylin & eosin(H&E) slide examination, and p53 and beta-catenin expression via immunohistochemistry (IHC). Correlations between non-parametric variables were assessed using Chi-square and Spearman correlation tests.

RESULTS

The study found significantly higher MIR34A expression in patients aged 60 years and less (26/41, p=0.024) and a higher prevalence of MIR21 in male patients (23/35, p=0.012). TILs at the tumour advancing front were categorized as low (≤10 %) or high (≥15 %). Among the 36 cases with low TILs, high MIR34A and high MIR31 expressions were observed in 24 cases (p=0.016) and 23 cases (p=0.03), respectively. Conversely, 21 of 33 cases with high TILs had low expressions of both MIR34A and MIR31. High TILs were more common in early-stage CRC (TNM stages I-IIIA), with 20 out of 28 cases, compared to 28 of 41 cases in later stages (IIIB-IVC) exhibiting low TILs (p=0.003). Aberrant p53 expression correlated with lower MIR34A levels, consistent with TCGA data.

CONCLUSION

Lower MIR34A and MIR31 levels are associated with higher TILs density in CRC. Unlike other cancers where MIR34A has anti-tumour effects, there was no statistically significant correlation between its expression and the pT or TNM stages in this study. Increased TILs being a good prognostic indicator, this suggests MIR34A and MIR31 may help CRC cells evade immune surveillance. Aberrant p53 expression downregulates MIR34A, underscoring the therapeutic potential of miRs.

Effect of miR-34a on the expression of clock and clock-controlled genes in DLD1 and Lovo human cancer cells with different backgrounds with respect to p53 functionality and 17β-estradiol-mediated regulation

The small non-coding RNA miR-34a is a p53-regulated miRNA that acts as a tumour suppressor of colorectal cancer (CRC). Oncogenesis is also negatively influenced by deregulation of the circadian system in many types of tumours with various genetic backgrounds. As the clock gene per2 was recently recognized as one of the target genes of miR-34a, we focused on the miR-34a-mediated influence on the circadian oscillator in CRC cell lines DLD1 and LoVo, which differ in their p53 status. Previously, a sex-dependent association between the expression of per2 and that of miR-34a was demonstrated in CRC patients. Therefore, we also investigated the effect of 17β-estradiol (E2) on miR-34a oncostatic functions. miR-34a mimic caused a pronounced inhibition of per2 expression in both cell lines. Moreover, miR-34a mimic significantly inhibited bmal1 expression in LoVo and rev-erbα expression in DLD1 cells and induced clock gene expression in both cell lines. miR-34a mimic caused a pronounced decrease in sirt1 and cyclin D1 expression, which may be related to the inhibition of proliferation observed after mir-34a administration in DLD1 cells. E2 administration inhibited the migration and proliferation of DLD1 cells. E2 and miR-34a, when administered simultaneously, did not potentiate each other's effects. To conclude, miR-34a strongly influences the expression of components of the circadian oscillator without respect to p53 status and exerts its oncostatic effects via inhibition of sirt1 and cyclin D1 mRNA expression. E2 administration inhibits the growth of DLD1 cells; however, this effect seems to be independent of miR-34a-mediated action. With respect to the possible use of miR-34a in cancer treatment, clock genes can be considered as off-target genes, as changes in their expression induced by miR-34a treatment do not contribute to the oncostatic functions of miR-34a. Possible ambiguous oncogenic characteristics should be taken into consideration in future clinical studies focused on miR-34a.

High Intratumoral i-tRF-GlyGCC Expression Predicts Short-Term Relapse and Poor Overall Survival of Colorectal Cancer Patients, Independent of the TNM Stage

Colorectal cancer (CRC), one of the most prevalent types of cancer, requires the discovery of new tumor biomarkers for accurate patient prognosis. In this work, the prognostic value of the tRNA fragment i-tRF-Gly^GCC in CRC was examined. Total RNA extraction from 211 CRC patient cancer tissue specimens and 83 adjacent normal tissues was conducted. Each RNA extract was subjected to in vitro polyadenylation and reverse transcription. A real-time quantitative PCR assay was used to quantify i-tRF-Gly^GCC in all samples. Extensive biostatics analysis showed that i-tRF-Gly^GCC levels in CRC tissues were significantly lower than in matched normal colorectal tissues. Additionally, the disease-free survival (DFS) and overall survival (OS) time intervals were considerably shorter in CRC patients with high i-tRF-Gly^GCC expression. i-tRF-Gly^GCC expression maintained its prognostic value independently of other established prognostic factors, as shown by the multivariate Cox regression analysis. Additionally, survival analysis after TNM stage stratification revealed that higher i-tRF-Gly^GCC levels were linked to shorter DFS time intervals in patients with TNM stage II tumors, as well as an increased probability of having a worse OS for patients in TNM stage II. In conclusion, i-tRF-Gly^GCC has the potential to be a useful molecular tissue biomarker in CRC, independent of other clinicopathological variables.

MicroRNA-675-5p Overexpression Is an Independent Prognostic Molecular Biomarker of Short-Term Relapse and Poor Overall Survival in Colorectal Cancer

Colorectal cancer (CRC) is the main cause of cancer-related deaths globally, highlighting the importance of accurate biomarkers for early detection and accurate prognosis. MicroRNAs (miRNAs) have emerged as effective cancer biomarkers. The aim of this study was to investigate the prognostic potential of miR-675-5p as a molecular prognostic biomarker in CRC. For this reason, a quantitative PCR assay was developed and applied to determine miR-675-5p expression in cDNAs from 218 primary CRC and 90 paired normal colorectal tissue samples. To assess the significance of miR-675-5p expression and its association with patient outcome, extensive biostatistical analysis was performed. miR-675-5p expression was found to be significantly downregulated in CRC tissue samples compared to that in adjacent normal colorectal tissues. Moreover, high miR-675-5p expression was associated with shorter disease-free (DFS) and overall survival (OS) in CRC patients, while it maintained its unfavorable prognostic value independently of other established prognostic factors. Furthermore, TNM stage stratification demonstrated that higher miR-675-5p levels were associated with shorter DFS and OS intervals, particularly in patients with CRC of TNM stage II or III. In conclusion, our findings suggest that miR-675-5p overexpression constitutes a promising molecular biomarker of unfavorable prognosis in CRC, independent of other established prognostic factors, including TNM staging.

MicroRNA Methylome Signature and Their Functional Roles in Colorectal Cancer Diagnosis, Prognosis, and Chemoresistance

Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths worldwide. Despite significant advances in the diagnostic services and patient care, several gaps remain to be addressed, from early detection, to identifying prognostic variables, effective treatment for the metastatic disease, and the implementation of tailored treatment strategies. MicroRNAs, the short non-coding RNA species, are deregulated in CRC and play a significant role in the occurrence and progression. Nevertheless, microRNA research has historically been based on expression levels to determine its biological significance. The exact mechanism underpinning microRNA deregulation in cancer has yet to be elucidated, but several studies have demonstrated that epigenetic mechanisms play important roles in the regulation of microRNA expression, particularly DNA methylation. However, the methylation profiles of microRNAs remain unknown in CRC patients. Methylation is the next major paradigm shift in cancer detection since large-scale epigenetic alterations are potentially better in identifying and classifying cancers at an earlier stage than somatic mutations. This review aims to provide insight into the current state of understanding of microRNA methylation in CRC. The new knowledge from this study can be utilized for personalized health diagnostics, disease prediction, and monitoring of treatment.

LncRNA AK077216 affects the survival of colorectal adenocarcinoma patients via miR-34a

BACKGROUND AND STUDY AIMS

It has been reported that long non-coding RNA (lncRNA) AK077216 involves in osteoclastogenesis and bone resorption. Our preliminary data has revealed that AK077216 was downregulated in colorectal adenocarcinoma (CRA) and it was closely correlated with miR-34a. This study was carried out to explore the role of AK077216 in CRA with a focus on its interactions with miR-34a.

PATIENTS AND METHODS

Paired CRA and non-tumor tissues collected from 66 CRA patients were subjected to RNA preparations, followed by RT-qPCRs to determine the expression levels of AK077216 and miR-34a. The interactions between AK077216 and miR-34a were analyzed with overexpression assays. Transwell assays were carried out to explore the roles of AK077216 and miR-34a in regulating CRA cell invasion and migration.

RESULTS

AK077216 was downregulated in CRA tissues compared to that in non-tumor tissues of CRA patients. During a 5-year follow-up, patients with lower expression levels of AK077216 in CRA tissues showed significantly lower overall survival. MiR-34a was upregulated in CRA tissues and inversely correlated with AK077216. Overexpression of AK077216 decreased the expression levels of miR-34a, while overexpression of miR-34a did not affect the expression of AK077216. Overexpression of AK077216 inhibited CRA cell migration and invasion, while overexpression of miR-34a accelerated cancer cell migration and invasion and attenuated the effects of overexpression on AK077216 on cell behaviors.

CONCLUSION

Therefore, AK077216 may inhibit CRA cell migration and invasion by downregulating miR-34a.

Could miR-34a Inhibition be Used as a Tool to Overcome Drug Resistance in MCF-7 Cells Treated with Synthesized Steroidal Heterocycles?

Background:

Progesterone derivatives have explored an improved effect on human cancer cells through combination of the explored heterocycles with progesterone moiety.miRNAs have an important role in moderating cancer cell survival, proliferation and drug resistance. The current study tested the hypothesis “whether miR-34a inhibitor has a negative impact on apoptosis and angiogenesis in MCF-7 cells treated with newly synthesized progesterone derivatives”.

Methods:

MCF-7 cells were treated with progesterone derivatives individually and in combination with miR-34a inhibitor. miR-34a expression levels were measured in MCF-7 cells treated with progesterone derivatives using QRT-PCR. MCF-7 cells treated with progesterone derivatives individually showed increased miR-34a expression levels. miR-34a deficient cells were treated with the newly synthesized progesterone derivatives, after that, apoptotic and angiogenic gene expression levels were determined using QRT-PCR. The studied genes were as follows: apoptotic (Bcl-2, survivin, CCND1, CDC2, P53 and P21) and angiogenic (VEGF, Hif-1α, MMP-2, Ang-1, Ang-2, and FGF-1).

Results:

The results showed that miR-34a deficient MCF-7 cells treated with the newly progesterone derivatives still have promising effects on apoptotic and angiogenic genes. Besides, results revealed that miRNA-34a deficient MCF-7 cells exhibited improved effect of tested compounds in some apoptotic and angiogenic genes such as CDC-2, MMP-2.

Conclusion:

These results revealed that miR-34a inhibitor did not have remarkable negative effect on apoptosis and angiogenesis. On contrary, it showed an improved effect on some genes. And consequently, miR-34a inhibitor could be used safely as a tool to tackle drug resistance in breast cancer cells.

Tissue micro-RNAs associated with colorectal cancer prognosis: a systematic review

Colorectal cancer (CRC) is a multifactorial disease commonly diagnosed worldwide, with high mortality rates. Several studies demonstrate important associations between differential expression of micro-RNAs (miRs) and the prognosis of CRC. The present study aimed to identify differentially expressed tissue miRs associated with prognostic factors in CRC patients, through a systematic review of the Literature. Using the PubMed database, Cochrane Library and Web of Science, studies published in English evaluating miRs differentially expressed in tumor tissue and significantly associated with the prognostic aspects of CRC were selected. All the included studies used RT-PCR (Taqman or SYBR Green) for miR expression analysis and the period of publication was from 2009 to 2018. A total of 115 articles accomplished the inclusion criteria and were included in the review. The studies investigated the expression of 100 different miRs associated with prognostic aspects in colorectal cancer patients. The most frequent oncogenic miRs investigated were miR-21, miR-181a, miR-182, miR-183, miR-210 and miR-224 and the hyperexpression of these miRs was associated with distant metastasis, lymph node metastasis and worse survival in patients with CRC. The most frequent tumor suppressor miRs were miR-126, miR-199b and miR-22 and the hypoexpression of these miRs was associated with distant metastasis, worse prognosis and a higher risk of disease relapse (worse disease-free survival). Specific tissue miRs are shown to be promising prognostic biomarkers in patients with CRC, given their strong association with the prognostic aspects of these tumors, however, new studies are necessary to establish the sensibility and specificity of the individual miRs in order to use them in clinical practice.

MicroRNAs as potential investigative and predictive biomarkers in colorectal cancer

Colorectal cancer (CRC) is a noticeable reason of cancer-associated deaths with a high incidence and mortality rate. Countless effort have been put into the improving clinical management of CRC patients including more effective tools and a wide variety of biomarkers for diagnostic, prognostic or predictive purposes. In recent years, dysregulated miRNAs have been emerged as highly sensitive and specific markers to manage CRC in an effective way. They can play key roles in carcinogenesis as potential oncogenes, tumor suppressors or regulators of cancer network. Therefore, miRNAs may serve as molecular tools that can be quantified and used in diagnostic and prognostic approaches. Growing evidence also suggests that forced expression of tumor suppressor miRNAs or inhibiting the oncogene ones, can be used as a novel treatment strategy. In this review, we focus on the clinical applications of miRNAs as promising biomarkers of early cancer detection, prognosis and treatment.

Low expression of miR-20b-5p indicates favorable prognosis in laryngeal squamous cell carcinoma, especially in patients with non-infiltrated regional lymph nodes

PURPOSE

Tumor recurrence and distant metastasis are very common in laryngeal squamous cell carcinoma (LSCC). In this study, we examined the potential prognostic value of microRNA-20b-5p (miR-20b-5p), a component of the tumor-related miR-106a/363 cluster.

MATERIALS AND METHODS

Total RNA was purified from 105 tissue specimens resected from patients having undergone surgical treatment for primary LSCC. After in vitro polyadenylation and reverse transcription, a sensitive real-time quantitative polymerase chain reaction (qPCR) methodology was applied for the relative quantification of miR-20b-5p levels. Then, we proceeded with biostatistical analysis, seeking to assess the prognostic value of miR-20b-5p expression in LSCC.

RESULTS

miR-20b-5p positivity constitutes a predictor of inferior DFS and OS in LSCC (P < 0.001 and P = 0.002, respectively). The significant prognostic value of miR-20b-5p expression status seems to be independent of tumor size, histological grade, and TNM stage, as revealed by the multivariate bootstrap Cox regression analysis. Kaplan-Meier survival analysis showed also that miR-20b-5p expression status can stratify LSCC patients with non-infiltrated regional lymph nodes (N0) into two subgroups with distinct prognosis (P = 0.004 and P = 0.004, respectively).

CONCLUSIONS

The miR-20b-5p expression status is a promising molecular tissue biomarker in LSCC, with an independent prognostic value, and thus merits further validation in larger cohorts of patients.

Regulatory and immunomodulatory role of miR-34a in T cell immunity

miRNAs are a class of non-coding RNAs and very conserve molecules that negatively regulate the expression of many genes by targeting the 3' UTR of mRNAs. miRNAs are involved in the modulation of T-cell biology during the earliest and last stages and key controllers of T-cell differentiation and function. The miR-34a, as a major hub of the regulatory network of T cells, plays an important role in T cell activation. miR-34a is widely expressed in immune cells (dendritic cells, macrophages, mast cells, B cells, and T cells) and regulates their development, function, and survival. This miRNA, by targeting over 30 genes across different cellular pathways controls immune response. miR-34a expression is controlled by p53 in transcription level. As well as, miR-34a by activating dendritic cells mediates innate immune response and increases tumor-infiltrating CD8 expression T lymphocytes. In various types of cancers and autoimmune diseases, miR-34a can regulate T cell function and become a possible significant target of microRNA-based therapy. Therefore, in this review, we focus on miR-34a-related regulatory mechanisms in T cell function and understanding mechanisms and molecules involved in this network.

Clinical Significance and Prognostic Value of miR-28-5p in Colon Cancer

Background

The association of miR-28-5p with colon cancer remains to be elucidated. This study aimed to determine the clinical significance and prognostic value of miR-28-5p in colon cancer.

Methods

We retrospectively analyzed the data of miR-28-5p in colon adenocarcinoma data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO), and the data was divided into cancer group and normal group, respectively. Forty colon cancer tissues and adjacent normal tissues were collected and tested by qRT-PCR methods. The difference of the miR-28-5p expression between colon cancer and normal tissues was compared. The clinical significance of miR-28-5p in colon cancer and the association with the survival were determined. The predictive value of miR-28-5p in clinical features was determined using receiver operating characteristic curve. The target genes of miR-28-5p were identified, and the functional of target genes was performed using bioinformatics analysis.

Results

: The expression of miR-28-5p was increased in colon cancer tissues compared with normal controls (p = 0.037). The expression of miR-28-5p was significantly increased in tissues with distant metastases compared with that without distant metastases (p = 0.026). Patients with high expression of miR-28-5p have a shorter survival time than those with low expression (p = 0.004). Cox analysis showed that miR-28-5p was an independent predictor for the survival of patients (p = 0.014). Combination of miR-28-5p with TNM stage and clinical stage can improve the prognostic value for the patients (p < 0.05). miR-28-5p has a moderate predictive value in predicting the TNM stage and clinical stage (T stage: AUC = 0.515; N stage: AUC = 0.523, M stage: AUC = 0.572; clinical stage: AUC = 0.539). 711 potential target genes of miR-28-5p were screened; their function and pathways were identified.

Conclusions

: This study demonstrated that miR-28-5p was increased in colon cancer and can be an independent indicator for the overall survival in patients with colon cancer.

miR-34a regulates adipogenesis in porcine intramuscular adipocytes by targeting ACSL4

BACKGROUND

Intramuscular fat (IMF) content is an important factor in porcine meat quality. Previously, we showed that miR-34a was less abundant in liver tissue from pigs with higher backfat thickness, compared to pigs with lower backfat thickness. The purpose of this present study was to explore the role of miR-34a in adipogenesis.

RESULT

Bioinformatics analysis identified Acyl-CoA synthetase long chain family member 4 (ACSL4) as a putative target of miR-34a. Using a luciferase reporter assay, we verified that miR-34a binds the ACSL4 mRNA at the 3'UTR. To examine the role of the miR-34a-ACSL4 interaction in IMF deposition in the pig, mRNA and protein expression of the ACSL4 gene was measured in primary intramuscular preadipocytes transfected with miR-34a mimic and inhibitor. Our results showed that ACSL4 is expressed throughout the entire differentiation process in pig preadipocytes, similar to the lipogenesis-associated genes PPARγ and aP2. Transfection with miR-34a mimic reduced lipid droplet formation during adipogenesis, while miR-34a inhibitor increased lipid droplet accumulation. Transfection with miR-34a mimic also reduced the mRNA and protein expression of ACSL4 and lipogenesis genes, including PPARγ, aP2, and SREBP-1C, but increased the expression of steatolysis genes such as ATGL and Sirt1. In contrast, the miR-34a inhibitor had the opposite effect on gene expression. Further, knockdown of ACSL4 decreased lipid droplet accumulation.

CONCLUSIONS

Our results support the hypothesis that miR-34a regulates intramuscular fat deposition in porcine adipocytes by targeting ACSL4.

Heat shock protein beta 3 (HSPB3) is an unfavorable molecular biomarker in colorectal adenocarcinoma

Small heat shock proteins (sHSPs) participate in numerous cellular functions including cell signaling, differentiation, and apoptosis. Deregulation of the physiological expression level of sHSPs has been associated with several malignancies. Heat shock protein beta 3 (HSPB3) is the third member of the sHSP family in human and is mainly expressed in skeletal and smooth muscles. In this study, we investigated the potential prognostic significance of HSPB3 expression in colorectal adenocarcinoma, the most frequent type of colorectal cancer. For this purpose, we isolated total RNA from 188 colorectal adenocarcinoma specimens and 68 paired noncancerous ones. After reverse transcription of 2 μg total RNA, we quantified HSPB3 levels by using an in-house-developed real-time quantitative polymerase chain reaction method, based on the SYBR Green chemistry. Comparison of HSPB3 levels among 68 pairs of colorectal tumors and their adjacent noncancerous mucosae uncovered the downregulation of HSPB3 expression in the majority of malignant colorectal tumors. More importantly, high HSPB3 expression is associated with poor relapse-free survival (RFS) and overall survival (OS) of patients with colorectal adenocarcinoma. Multivariable Cox regression analysis revealed that HSPB3 overexpression could serve as an adverse prognostic biomarker in colorectal adenocarcinoma, independent of tumor location, histological grade, and TNM stage. Patients' stratification according to tumor location, histological grade, and TNM stage revealed that high HSPB3 messenger RNA expression retains its unfavorable prognostic potential regarding OS, in particular groups of patients with substantially different prognosis. In conclusion, high HSPB3 expression is associated with poor RFS and OS of patients with colorectal adenocarcioma, independently of clinicopathological prognosticators.

Expression of miR-34a-5p is up-regulated in human colorectal cancer and correlates with survival and clock gene PER2 expression

Colorectal cancer represents a leading cause of cancer death. MicroRNAs (miRNAs) are small non-coding RNA molecules that have been extensively studied in tumours, since changes in their levels can reveal patient prognosis. Cancer progression is also influenced by the circadian system whose functioning is based on the rhythmic expression of clock genes. Therefore, we performed macroarray screening of tumour and adjacent tissues in patients undergoing surgery for colorectal carcinoma. We identified 17 miRNAs showing expression that was more than 100 times higher in tumour tissue compared to adjacent tissue. From in silico analysis, miR-34a-5p was selected as showing a computer-predicted interaction with PER2. Real-time PCR revealed a negative correlation between expression of PER2 mRNA and miR-34a in patients with more advanced cancer stage. Expression of miR-34a was up-regulated in cancer tissue compared to adjacent tissue. High miR-34a expression was associated with better survival of patients. miR-34a showed lower expression levels in male patients with lymph node involvement, and a trend towards decreased expression in male patients with distant metastases. Male patients, but not female patients, with high expression of miR-34a and who were free of distant metastases and/or lymph node involvement showed better survival. Therefore, we proposed that expression of miR-34a was regulated in a sex-dependent manner and could be considered a marker of prognosis in earlier cancer stages in male patients.

Uncovering the clinical impact of kallikrein-related peptidase 5 (KLK5) mRNA expression in the colorectal adenoma-carcinoma sequence

Background Kallikrein-related peptidases (KLKs) are a subgroup of serine proteases located on chromosome 19q13.3. Most KLKs have been extensively studied as potential biomarkers for several carcinomas and other diseases. KLK5 was originally identified from a keratinocyte library, and its enzyme was purified from the stratum corneum of human skin. KLK5 was shown to be differentially expressed in a variety of endocrine tumors, although it is not as yet examined widely in colorectal cancer (CRC). Methods In this study, we quantitatively assessed the mRNA expression status of KLK5 in 197 colorectal tissues from 133 patients (70 cancerous and their paired normal colonic mucosa for 64 of them, as well as 63 colorectal adenomas) by quantitative real-time PCR (qPCR) using TaqMan probes. Statistical analysis evaluated the results. Results It was shown that KLK5 expression is reduced following the histologically non-cancerous-adenoma sequence (p<0.001), whereas it is increased during the sequence adenoma-carcinoma (p<0.001). Furthermore, KLK5 positive expression is associated with positive nodal status (p=0.022), advanced tumor stage (p=0.038) and high histological grade (p=0.033). Cox univariate analysis revealed that KLK5 positive expression is associated with disease-free survival (DFS) (p=0.028) and overall survival (OS) of patients (p=0.048). Kaplan-Meyer survival models showed that patients with positive KLK5 expression have lower DFS (p=0.009) and OS (p=0.019). Receiver operating characteristic (ROC) analysis demonstrated for first time that KLK5 expression had significant discriminatory values between cancer and adenoma tissues (area under the curve [AUC] 0.77; 95% confidence interval [CI]=0.69-0.85, p=0.03). Conclusions KLK5 mRNA expression may be useful for the differentiation of CRC from colorectal adenoma and represents a potential unfavorable prognostic biomarker for CRC.

Expression of vimentin (VIM) and metastasis-associated 1 (MTA1) protein in laryngeal squamous cell carcinoma are associated with prognostic outcome of patients

PURPOSE

Laryngeal squamous cell carcinoma (LSCC), a common type of head and neck cancer, is associated with high rates of metastasis and recurrence. In this study, we investigated the potential combinatorial prognostic value of NOTCH1, Vimentin (VIM), and Metastasis-associated 1 (MTA1) protein in LSCC, using immunohistochemistry.

MATERIALS AND METHODS

Tissue specimens from 69 patients with LSCC were immunohistochemically evaluated for the protein expression of NOTCH1, VIM, and MTA1. Then, biostatistical analysis was performed, in order to assess the prognostic value of the expression of each one of these proteins.

RESULTS

NOTCH1 expression status was not a significant prognosticator in LSCC, as shown in Kaplan-Meier survival analysis. On the contrary, both VIM and MTA1 seem to have an important prognostic potential, independently of TNM staging and histological grade of the tumor. In fact, positive VIM expression was shown to predict patients' relapse and poor outcome regarding patients' overall survival, in contrast with MTA1, the positive expression of which predicts higher disease-free survival (DFS) and overall survival (OS) rates in LSCC.

CONCLUSIONS

VIM and MTA1 constitute potential tumor biomarkers in LSCC and could be integrated into a multiparametric prognostic model. Undoubtedly, their prognostic value needs further validation in larger cohorts of LSCC patients.

lncRNA KCNQ1OT1 enhances the chemoresistance of oxaliplatin in colon cancer by targeting the miR-34a/ATG4B pathway

Purpose

The chemoresistance of colon cancer to oxaliplatin (L-OHP) indicates poor prognosis. Long non-coding RNA (lncRNA) KCNQ1OT1 (KCNQ1 opposite strand/antisense transcript 1) has been shown to participate in the tumorigenesis of several types of cancers. However, little is known about the role of KCNQ1OT1 in the chemoresistance and prognosis of colon cancer.

Materials and methods

Quantitative-PCR and Western blot were used to measure the expression profiles of KCNQ1OT1, miR-34a, and Atg4B in colon cancer tissues and cells. Cell viability assay and flow cytometry were used to examine their effects on cell proliferation and death. Cleavage of LC3 and GFP-LC3 plasmid transfection were used to detect autophagic activity. Double luciferase reporter assay was used to verify the interactions between miRNA and lncRNA or mRNA. Xenograft tumor model was used to verify the effects of KCNQ1OT1 in vivo.

Results

In this study, it is shown that the expression level of KCNQ1OT1 was increased in tumor, which indicated poor prognosis in colon cancer patients. Using colon cancer cell lines HCT116 and SW480, it was demonstrated that knockdown of KCNQ1OT1 decreased the cell viability and increased the apoptosis rates upon L-OHP treatment. Further studies indicated that Atg4B upregulation was partially responsible for KCNQ1OT1-induced protective autophagy and chemoresistance. Moreover, miR-34a functioned as a bridge between KCNQ1OT1 and Atg4B, which could be sponged by KCNQ1OT1, while it could also bind to the 3'-UTR of Atg4B and downregulate its expressions. Finally, we show that the KCNQ1OT1/miR-34a/Atg4B axis regulated the chemoresistance of colon cancer cells in vitro and in vivo.

Conclusion

lncRNA KCNQ1OT1 promoted the chemoresistance of colon cancer by sponging miR-34a, thus upregulating the expressions of Atg4B and enhancing protective autophagy. KCNQ1OT1 might become a promising target for colon cancer therapeutics.

High microRNA-28-5p expression in colorectal adenocarcinoma predicts short-term relapse of node-negative patients and poor overall survival of patients with non-metastatic disease

BACKGROUND

MicroRNAs (miRNAs) may function either as oncogenes or tumor suppressors and are heavily involved in the initiation and progression of cancer, and in metastasis of tumor cells. MicroRNA-28-5p (miR-28-5p) targets several cancer-related genes and is hence involved in cell proliferation, migration, invasion and epithelial-mesenchymal transition. In this study, we investigated the potential diagnostic and prognostic significance of miR-28-5p expression in colorectal adenocarcinoma, the most frequent type of colorectal cancer (CRC).

METHODS

Therefore, we isolated total RNA from 182 colorectal adenocarcinoma specimens and 86 paired non-cancerous colorectal mucosae. After polyadenylation of 2 μg total RNA and its reverse transcription using an oligo-dT-adapter primer, we quantified miR-28-5p levels using an in-house-developed reverse-transcription real-time quantitative polymerase chain reaction (RT-qPCR) method, based on the SYBR Green chemistry.

RESULTS

Comparison of miR-28-5p levels among 86 pairs of colorectal tumors and their adjacent non-cancerous mucosae uncovered the downregulation of miR-28-5p expression in the majority of malignant colorectal tumors. More importantly, high miR-28-5p expression predicts poor disease-free survival (DFS) and overall survival (OS) of colorectal adenocarcinoma patients. Multivariate Cox regression analysis revealed that miR-28-5p overexpression is a significant predictor of poor prognosis in colorectal adenocarcinoma, independent of tumor size, histological grade, TNM staging, radiotherapy and chemotherapy. Interestingly, strong miR-28-5p expression retains its predictive potential regarding relapse among patients with negative regional lymph nodes, and predicts poor OS in patients diagnosed with non-metastatic colorectal adenocarcinoma.

CONCLUSIONS

High miR-28-5p expression predicts poor DFS and OS of colorectal adenocarcinoma patients, independently of clinicopathological prognosticators and standard patient treatment, including radiotherapy and chemotherapy.

Kallikrein-related peptidases and associated microRNAs as promising prognostic biomarkers in gastrointestinal malignancies

Gastrointestinal (GI) malignancies represent a wide spectrum of diseases of the GI tract and its accessory digestive organs, including esophageal (EC), gastric (GC), hepatocellular, pancreatic (PC) and colorectal cancers (CRC). Malignancies of the GI system are responsible for nearly 30% of cancer-related morbidity and approximately 40% of cancer-related mortality, worldwide. For this reason, the discovery of novel prognostic biomarkers that can efficiently provide a better prognosis, risk assessment and prediction of treatment response is an imperative need. Human kallikrein-related peptidases (KLKs) are a subgroup of trypsin and chymotrypsin-like serine peptidases that have emerged as promising prognosticators for many human types of cancer, being aberrantly expressed in cancerous tissues. The aberrant expression of KLKs in human malignancies is often regulated by KLK/microRNAs (miRNAs) interactions, as many miRNAs have been found to target KLKs and therefore alter their expression levels. The biomarker utility of KLKs has been elucidated not only in endocrine-related human malignancies, including those of the prostate and breast, but also in GI malignancies. The main purpose of this review is to summarize the existing information regarding the prognostic significance of KLKs in major types of GI malignancies and highlight the regulatory role of miRNAs on the expression levels of KLKs in these types of cancer.

Quantitative analysis and study of the mRNA expression levels of apoptotic genes BCL2, BAX and BCL2L12 in the articular cartilage of an animal model of osteoarthritis

Background

Given that apoptosis of chondrocytes is one of the most important factors related to the pathogenesis of osteoarthritis (OA), the recent research interest adds progress not only to the knowledge of the molecular signals that mediate apoptosis but also to find new therapeutic targets. This study attempts to investigate the differential expression of BCL2 family genes in the articular cartilage of an experimental animal model of OA.

Methods

In total, 26 New Zealand white rabbits underwent an anterior cruciate ligament transaction, 26 more were subjected to a placebo surgery and 18 specimens constituted the control non-operated group. Thirteen weeks later, samples of cartilage from the osteoarthritic and non-osteoarthritic knees were collected and subjected to analysis of the BCL2, BAX and BCL2L12 gene expression at the mRNA level.

Results

Installed osteoarthritic alterations of varied intensity and of grade 1 up to grade 5, were confirmed according to the OARSI system. Contrary to the physiologically healthy samples, in the osteoarthritic samples the mRNA expression levels of BAX and BCL2L12 genes were found significantly upregulated by signals which can activate apoptosis. However, the difference between BCL2 mRNA expression levels in healthy and osteoarthritic samples was not supported statistically.

Conclusions

Since apoptosis is the main feature of the cartilage degeneration in OA, the effective inhibition of apoptosis of chondrocytes can provide novel and interesting therapeutic strategies for the treatment of OA. Therefore, BAX and BCL2L12 are highlighted as potential therapeutic targets in OA.

Alternative Splicing Detection Tool-a novel PERL algorithm for sensitive detection of splicing events, based on next-generation sequencing data analysis

Next-generation sequencing (NGS) can provide researchers with high impact information regarding alternative splice variants or transcript identifications. However, the enormous amount of data acquired from NGS platforms make the analysis of alternative splicing events hard to accomplish. For this reason, we designed the "Alternative Splicing Detection Tool" (ASDT), an algorithm that is capable of identifying alternative splicing events, including novel ones from high-throughput NGS data. ASDT is available as a PERL script at http://aias.biol.uoa.gr/~mtheo and can be executed on any system with PERL installed. In addition to the detection of annotated and novel alternative splicing events from high-throughput NGS data, ASDT can also analyze the intronic regions of genes, thus enabling the detection of novel cryptic exons residing in annotated introns, extensions of previously annotated exons, or even intron retentions. Consequently, ASDT demonstrates many innovative and unique features that can efficiently contribute to alternative splicing analysis of NGS data.

Non-coding RNAs: the riddle of the transcriptome and their perspectives in cancer

Non-coding RNAs (ncRNAs) constitute a heterogeneous group of RNA molecules in terms of biogenesis, biological function as well as length and structure. These biological molecules have gained attention recently as a potentially crucial layer of tumor cell progression or regulation. ncRNAs are expressed in a broad spectrum of tumors, and they play an important role not only in maintaining but also in promoting cancer development and progression. Recent discoveries have revealed that ncRNAs may act as key signal transduction mediators in tumor signaling pathways by interacting with RNA or proteins. These results reinforce the hypothesis, that ncRNAs constitute therapeutic targets, and point out their clinical potential as stratification markers. The major purpose of this review is to mention the emergence of the importance of ncRNAs, as molecules which are correlated with cancer, and to discuss their clinical implicit as prognostic diagnostic indicators, biomarkers, and therapeutic targets.

MicroRNA-34a: A Versatile Regulator of Myriads of Targets in Different Cancers

MicroRNA-34a (miR-34a) is a tumor suppressor that has attracted considerable attention in recent years. It modulates cancer cell invasion, metastasis, and drug resistance, and has also been evaluated as a diagnostic and/or prognostic biomarker. A number of targets of miR-34a have been identified, including some other non-coding RNAs, and it is believed that the modulation of these myriads of targets underlines the versatile role of miR-34a in cancer progression and pathogenesis. Seemingly appealing results from preclinical studies have advocated the testing of miR-34a in clinical trials. However, the results obtained are not very encouraging and there is a need to re-interpret how miR-34a behaves in a context dependent manner in different cancers. In this review, we have attempted to summarize the most recent evidence related to the regulation of different genes and non-coding RNAs by miR-34a and the advances in the field of nanotechnology for the targeted delivery of miR-34a-based therapeutics and mimics. With the emergence of data that contradicts miR-34a’s tumor suppressive function, it is important to understand miR-34a’s precise functioning, with the aim to establish its role in personalized medicine and to apply this knowledge for the identification of individual patients that are likely to benefit from miR-34a-based therapy.