Aldose reductase inhibition suppresses colon cancer cell viability by modulating microRNA-21 mediated programmed cell death 4 (PDCD4) expression

Aldo-keto reductases: Role in cancer development and theranostics

Aldo-keto reductases (AKRs) are a superfamily of enzymes that play crucial roles in various cellular processes, including the metabolism of xenobiotics, steroids, and carbohydrates. A growing body of evidence has unveiled the involvement of AKRs in the development and progression of various cancers. AKRs are aberrantly expressed in a wide range of malignant tumors. Dysregulated expression of AKRs enables the acquisition of hallmark traits of cancer by activating oncogenic signaling pathways and contributing to chemoresistance. AKRs have emerged as promising oncotherapeutic targets given their pivotal role in cancer development and progression. Inhibition of aldose reductase (AR), either alone or in combination with chemotherapeutic drugs, has evolved as a pragmatic therapeutic option for cancer. Several classes of synthetic aldo-keto reductase (AKR) inhibitors have been developed as potential anticancer agents, some of which have shown promise in clinical trials. Many AKR inhibitors from natural sources also exhibit anticancer effects. Small molecule inhibitors targeting specific AKR isoforms have shown promise in preclinical studies. These inhibitors disrupt the activation of oncogenic signaling by modulating transcription factors and kinases and sensitizing cancer cells to chemotherapy. In this review, we discuss the physiological functions of human AKRs, the aberrant expression of AKRs in malignancies, the involvement of AKRs in the acquisition of cancer hallmarks, and the role of AKRs in oncogenic signaling, and drug resistance. Finally, the potential of aldose reductase inhibitors (ARIs) as anticancer drugs is summarized.

The polyol pathway and nuclear ketohexokinase A signaling drive hyperglycemia-induced metastasis of gastric cancer

Diabetes might be associated with increased cancer risk, with several studies reporting hyperglycemia as a primary oncogenic stimulant. Since glucose metabolism is linked to numerous metabolic pathways, it is difficult to specify the mechanisms underlying hyperglycemia-induced cancer progression. Here, we focused on the polyol pathway, which is dramatically activated under hyperglycemia and causes diabetic complications. We investigated whether polyol pathway-derived fructose facilitates hyperglycemia-induced gastric cancer metastasis. We performed bioinformatics analysis of gastric cancer datasets and immunohistochemical analyses of gastric cancer specimens, followed by transcriptomic and proteomic analyses to evaluate phenotypic changes in gastric cancer cells. Consequently, we found a clinical association between the polyol pathway and gastric cancer progression. In gastric cancer cell lines, hyperglycemia enhanced cell migration and invasion, cytoskeletal rearrangement, and epithelial-mesenchymal transition (EMT). The hyperglycemia-induced acquisition of metastatic potential was mediated by increased fructose derived from the polyol pathway, which stimulated the nuclear ketohexokinase-A (KHK-A) signaling pathway, thereby inducing EMT by repressing the CDH1 gene. In two different xenograft models of cancer metastasis, gastric cancers overexpressing AKR1B1 were found to be highly metastatic in diabetic mice, but these effects of AKR1B1 were attenuated by KHK-A knockdown. In conclusion, hyperglycemia induces fructose formation through the polyol pathway, which in turn stimulates the KHK-A signaling pathway, driving gastric cancer metastasis by inducing EMT. Thus, the polyol and KHK-A signaling pathways could be potential therapeutic targets to decrease the metastatic risk in gastric cancer patients with diabetes.

MicroRNA-183 cluster: a promising biomarker and therapeutic target in gastrointestinal malignancies

Small non-coding RNAs (microRNA, miR), powerful epigenetic regulators, were found involved in the regulation of most biological functions via post-translational inhibition of protein expression. Increased expression of pro-oncogenic miRs (known as miR cancer biomarkers) and inhibition of pro-apoptotic miR expression have been demonstrated in different tumors. The recently identified miR-183 was found implicated in gastrointestinal tumor metabolism regulation. Elevated miR-183 expression and cancer-promoting effects were reported in esophageal and colorectal cancers, which was partially contradicted by controversial data observed in gastric cancers. Anti-cancer effect of miR-183 in gastric cancer cells was associated with the Bim-1 and Ezrin genes regulation. Many studies indicated that miR-183 can inhibit tumor suppressor genes in most cell lines, promoting tumor cell proliferation and migration. Increased miR-183 level results in the downregulation of FOXO1, PDCD4, and other tumor suppressor genes in gastrointestinal tumor cells. MiR-183 also influences the signaling of PI3K/AKT/mTOR, Wnt/β-catenin, and Bcl-2/p53 signaling pathways. Mir-183 inhibits apoptosis and autophagy, and promotes epithelial-to-mesenchymal transition, cancer cell proliferation, and migration. Accordingly, gastrointestinal cancer occurrence, development of chemoradiotherapy resistance, recurrence/metastasis, and prognosis were associated with miR-183 expression. The current study assessed reported miR-183 functions and signaling, providing new insights for the diagnosis and treatment of gastrointestinal malignancies.

Molecular dissection of anti-colon cancer activity of NARI-29: special focus on H2O2 modulated NF-κB and death receptor signaling

Accumulating evidence attributes the role of aldose reductase (AR) in modulating ROS and inflammation which are the main factor responsible for cancer progression and drug resistance. Epalrestat is the only AR inhibitor being used in Asian countries. It did not make it to the markets of the USA and Europe due to marginal efficacy as an antioxidant and anti-inflammatory agent owing to difficulty reaching intracellular targets. In our previous studies, we attempted to synthesize the epalrestat analogs and reported that the compound 4-((Z)-5-((Z)-2-Cyano-3-phenylallylidene)-4-oxo-2-thioxothiazolidin-3-yl) benzoic acid named as NARI-29 has potent AR inhibition compared to epalrestat. In the current study, we aimed to find the effect of NARI-29 on ROS-induced cancer progression and TRAIL resistance in colon cancer in vitro models. In the first part of the study, we demonstrated that the NARI-29 has specific AKR1B1 inhibition and superior drug-like properties than epalrestat using bioinformatics tools. In the second part of the study, it was proven that NARI-29 has induced the hydrogen peroxide-triggered TRAIL-induced apoptosis in the colon cancer cells via modulating the AKR1B1/4HNE/FOXO3a/DR axis. The selective cytotoxicity of NARI-29 (10-fold) compared to epalrestat (4-fold) toward cancer cells is due to its differential ROS regulation and anti-inflammatory activities. Altogether, these data show that NARI-29 may be a potential candidate for AR inhibitors, which will be used to prevent colon cancer progression and as adjuvant therapy for preventing TRAIL resistance.

Lactobacillus casei condition medium downregulates miR-21 relative expression in HT-29 colorectal cancer cell line

Previous research has demonstrated promising outcomes regarding the advantageous impact of probiotics in both cancer prevention and treatment. Nevertheless, the precise molecular mechanisms underpinning these effects remain elusive. Recent investigations have proposed a potential involvement of micro ribonucleic acids (miRNAs) in mediating the favorable influence of probiotics on cancerous cells. This study was designed to evaluate the effect of Lactobacillus casei condition medium on miR-21 relative expression in HT-29 colorectal cancer cells. Lactobacillus casei condition medium mixed with RPMI in different proportions (1:1, 1:3, and 1:7) and utilized to treat HT-29 cells for 24 and 48 h. Subsequently, percentage of early and late apoptotic cells were identified using a flow cytometry instrument. A real-time polymerase chain reaction was carried out to determine the relative expression of miR-21. Our findings revealed that L. casei condition medium induces apoptosis in a time- and dose-dependent manner in HT-29 cells. Furthermore, we found a significantly downregulated miR-21 after treatment with high doses of L. casei condition medium after 48 h. Overall, our results provide valuable insights into a potential mechanism through which L. casei condition medium mediates its apoptotic effect in colorectal cancer cells through downregulation of miR-21. However, further investigations are required to unravel its therapeutic, diagnostic, and treatment monitoring potential.

The role of microRNA-21 in the onset and progression of cancer

MicroRNAs (miRNAs), a class of small noncoding RNA, posttranscriptionally regulate the expression of genes. Aberrant expression of miRNA is reported in various types of cancer. Since the first report of oncomiR-21 involvement in the glioma, its upregulation was reported in multiple cancers and was allied with high oncogenic property. In addition to the downregulation of tumor suppressor genes, the miR-21 is also associated with cancer resistance to various chemotherapy. The recent research is appraising miR-21 as a promising cancer target and biomarker for early cancer detection. In this review, we briefly explain the biogenesis and regulation of miR-21 in cancer cells. Additionally, the review features the assorted genes/pathways regulated by the miR-21 in various cancer and cancer stem cells.

Meta-inhibition of ocular and gastrointestinal dysfunctions by phenolic-rich fraction of Croton zambsicus leaves in a rat model exposed to chronic mixed metals

PURPOSE

This study was aimed at investigating the protective effect of antioxidant-rich fraction of Croton zambsicus (C-ZAMB) leaves on ocular-gastrointestinal dysfunction in rats exposed to environmental mixed-metal (EOMABRSL).

MATERIALS AND METHODS

The rats were divided into five (n = 10) groups. Group I designates the control which received 0.5 mL of distilled water. Group II and III received 0.5 mL of EOMABRSL for 98 days (non-withdrawal) and 70 days (withdrawal for 28 days), respectively. Group IV received 0.5 mL EOMABRSL for 70 days and 400 mg/kg C-ZAMB fraction for 28 days. Group V received 400 mg/kg C-ZAMB only for 28 days via oral route.

RESULTS

Exposure of the animals to EOMARBSL for 98 days and 70 days significantly up-regulated the activities of ocular-gastrointestinal aldolase-reductase, α-amylase, α-glucosidase and eco-5¹-nucleotidase with corresponding depletion of lactate dehydrogenase activity. Furthermore, exposure to EOMABRSL significantly altered the antioxidant proteins with up-production of MDA content. Apparently, management with 400 mg/kg C-ZAMB fraction significantly inhibited the key markers linked with ocular-gastrointestinal disorders.

CONCLUSION

Hence, this study underscores the biochemical mechanisms for managing ocular-gastrointestinal lesions by 400 mg/kg C-ZAMB fraction on exposure to mixture of environmental metals.

Evaluation of an aldo-keto reductase gene signature with prognostic significance in colon cancer via activation of epithelial to mesenchymal transition and the p70S6K pathway

AKR1B1 and AKR1B10, members of the aldo-keto reductase family of enzymes that participate in the polyol pathway of aldehyde metabolism, are aberrantly expressed in colon cancer. We previously showed that high expression of AKR1B1 (AKR1B1HIGH) was associated with enhanced motility, inflammation and poor clinical outcome in colon cancer patients. Using publicly available datasets and ex vivo gene expression analysis (n = 51, Ankara cohort), we have validated our previous in silico finding that AKR1B1HIGH was associated with worse overall survival (OS) compared with patients with low expression of AKR1B1 (AKR1B1LOW) samples. A combined signature of AKR1B1HIGH and AKR1B10LOW was significantly associated with worse recurrence-free survival (RFS) in microsatellite stable (MSS) patients and in patients with distal colon tumors as well as a higher mesenchymal signature when compared with AKR1B1LOW/AKR1B10HIGH tumors. When the patients were stratified according to consensus molecular subtypes (CMS), AKR1B1HIGH/AKR1B10LOW samples were primarily classified as CMS4 with predominantly mesenchymal characteristics while AKR1B1LOW/AKR1B10HIGH samples were primarily classified as CMS3 which is associated with metabolic deregulation. Reverse Phase Protein Array carried out using protein samples from the Ankara cohort indicated that AKR1B1HIGH/AKR1B10LOW tumors showed aberrant activation of metabolic pathways. Western blot analysis of AKR1B1HIGH/AKR1B10LOW colon cancer cell lines also suggested aberrant activation of nutrient-sensing pathways. Collectively, our data suggest that the AKR1B1HIGH/AKR1B10LOW signature may be predictive of poor prognosis, aberrant activation of metabolic pathways, and can be considered as a novel biomarker for colon cancer prognostication.

MicroRNA expression in lung tissues of asbestos-exposed mice: Upregulation of miR-21 and downregulation of tumor suppressor genes Pdcd4 and Reck

OBJECTIVES

Asbestos causes lung cancer and malignant mesothelioma in humans, but the precise mechanism has not been well understood. MicroRNA (miRNA) is a short non-coding RNA that suppresses gene expression and participates in human diseases including cancer. In this study, we examined the expression levels of miRNA and potential target genes in lung tissues of asbestos-exposed mice by microarray analysis.

METHODS

We intratracheally administered asbestos (chrysotile and crocidolite, 0.05 or 0.2 mg/instillation) to 6-week-old ICR male mice four times weekly. We extracted total RNA from lung tissues and performed microarray analysis for miRNA and gene expression. We also carried out real-time polymerase chain reaction (PCR), Western blotting, and immunohistochemistry to confirm the results of microarray analysis.

RESULTS

Microarray analysis revealed that the expression levels of 14 miRNAs were significantly changed by chrysotile and/or crocidolite (>2-fold, P < .05). Especially, miR-21, an oncogenic miRNA, was significantly upregulated by both chrysotile and crocidolite. In database analysis, miR-21 was predicted to target tumor suppressor genes programmed cell death 4 (Pdcd4) and reversion-inducing-cysteine-rich protein with kazal motifs (Reck). Although real-time PCR showed that Pdcd4 was not significantly downregulated by asbestos exposure, Western blotting and immunohistochemistry revealed that PDCD4 expression was reduced especially by chrysotile. Reck was significantly downregulated by chrysotile in real-time PCR and immunohistochemistry.

CONCLUSIONS

This is the first study demonstrating that miR-21 was upregulated and corresponding tumor suppressor genes were downregulated in lung tissues of asbestos-exposed animals. These molecular events are considered to be an early response to asbestos exposure and may contribute to pulmonary toxicity and carcinogenesis.

Aldo Keto Reductases AKR1B1 and AKR1B10 in Cancer: Molecular Mechanisms and Signaling Networks

Deregulation of metabolic pathways has increasingly been appreciated as a major driver of cancer in recent years. The principal cancer-associated alterations in metabolism include abnormal uptake of glucose and amino acids and the preferential use of metabolic pathways for the production of biomass and nicotinamide adenine dinucleotide phosphate (NADPH). Aldo-keto reductases (AKRs) are NADPH dependent cytosolic enzymes that can catalyze the reduction of carbonyl groups to primary and secondary alcohols using electrons from NADPH. Aldose reductase, also known as AKR1B1, catalyzes the conversion of excess glucose to sorbitol and has been studied extensively for its role in a number of diabetic pathologies. In recent years, however, high expression of the AKR1B and AKR1C family of enzymes has been strongly associated with worse outcomes in different cancer types. This review provides an overview of the catalysis-dependent and independent data emerging on the molecular mechanisms of the functions of AKRBs in different tumor models with an emphasis of the role of these enzymes in chemoresistance, inflammation, oxidative stress and epithelial-to-mesenchymal transition.

Oxidative Stress and Cancer Development: Are Noncoding RNAs the Missing Links?

Significance: It is now clear that genetic changes underlie the basis of cancer, and alterations in functions of multiple genes are responsible for the process of tumorigenesis. Besides the classical genes that are usually implicated in cancer, the role of noncoding RNAs (ncRNAs) and reactive oxygen species (ROS) as independent entitites has also been investigated. Recent Advances: The microRNAs and long noncoding RNAs (lncRNAs), two main classes of ncRNAs, are known to regulate many aspects of tumor development. ROS, generated during oxidative stress and pathological conditions, are known to regulate every step of tumor development. Conversely, oxidative stress and ROS producing agents can suppress tumor development. The malignant cells normally produce high levels of ROS compared with normal cells. The interaction between ROS and ncRNAs regulates the expression of multiple genes and pathways implicated in cancer, suggesting a unique mechanistic relationship among ncRNA-ROS-cancer. The mechanistic relationship has been reported in hepatocellular carcinoma, glioma, and malignancies of blood, breast, colorectum, esophagus, kidney, lung, mouth, ovary, pancreas, prostate, and stomach. The ncRNA-ROS regulate several cancer-related cell signaling pathways, namely, protein kinase B (AKT), epidermal growth factor receptor (EGFR), forkhead box O3 (FOXO3), kelch-like ECH-associated protein 1 (Keap1), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), nuclear factor erythroid 2-related factor 2 (Nrf2), p53, phosphatase and tensin homologue (PTEN), and wingless-related integration site (Wnt)/glycogen synthase kinase-3 beta (GSK3β). Critical Issues: To date, most of the reports about ncRNA-oxidative stress-carcinogenesis relationships are based on cell lines. The mechanistic basis for this relationship has not been completely elucidated. Future Directions: Attempts should be made to explore the association of lncRNAs with ROS. The significance of the ncRNA-oxidative stress-carcinogenesis interplay should also be explored through studies in animal models.

Role of aldo-keto reductase family 1 member B1 (AKR1B1) in the cancer process and its therapeutic potential

The role of aldo‐keto reductase family 1 member B1 (AKR1B1) in cancer is not totally clear but growing evidence is suggesting to have a great impact on cancer progression. AKR1B1 could participate in a complicated network of signalling pathways, proteins and miRNAs such as mir‐21 mediating mechanisms like inflammatory responses, cell cycle, epithelial to mesenchymal transition, cell survival and apoptosis. AKR1B1 has been shown to be mostly overexpressed in cancer. This overexpression has been associated with inflammatory mediators including nuclear factor kappa‐light‐chain‐enhancer of activated B cells (NFκB), cell cycle mediators such as cyclins and cyclin‐dependent kinases (CDKs), survival proteins and pathways like mammalian target of rapamycin (mTOR) and protein kinase B (PKB) or AKT, and other regulatory factors in response to reactive oxygen species (ROS) and prostaglandin synthesis. In addition, inhibition of AKR1B1 has been shown to mostly have anti‐cancer effects. Several studies have also suggested that AKR1B1 inhibition as an adjuvant therapy could render tumour cells more sensitive to anti‐cancer therapy or alleviate the adverse effects of therapy. AKR1B1 could also be considered as a potential cancer diagnostic biomarker since its promoter has shown high levels of methylation. Although pre‐clinical investigations on the role of AKR1B1 in cancer and the application of its inhibitors have shown promising results, the lack of clinical studies on AKR1B1 inhibitors has hampered the use of these drugs to treat cancer. Thus, there is a need to conduct more clinical studies on the application of AKR1B1 inhibitors as adjuvant therapy on different cancers.

QSAR-based rational discovery of novel substituted-4'-iminospiro[indoline-3,3'-[1,2,5]thiadiazolidinyl]-2-one 1',1'-dioxide with potent in vitro anticancer activity

Recent studies have suggested that aldose reductase inhibition preferentially inhibits the growth of cancer cells. However, the investigations of this issue are not many. Novel nine substituted- 4'-iminospiro[indoline-3,3'-[1,2,5] thiadiazolidinyl]-2-one 1',1'-dioxide derivatives were designed by both isosteric replacement of the imidazolidine-2,5-dione moiety in spirohydantoin scaffold and conformational rigidification approaches. A QSAR with high predictive power (r2 = 0.99) was created from a series of potent aldose reductase inhibitors and was used to predict the activity of our new compounds. Compound 5 showed the best docking score (- 33.24 kcal/mol) with the least RMSD value (< 1.5) obtained by molecular dynamic simulations over 20 ns. All compounds showed promising anticancer activities especially compound 5 that achieved the highest inhibitory activities with IC50; 0.013, 0.031, 0.064, and 0.048 mmol/L against breast, colon, prostate, and lung cell lines respectively. The discovery of this lead compound confirmed the rational design. Further investigations may be required for optimization of this compound.

Green Synthesized Silver Nanoparticles of Myrtus communis L (AgMC) Extract Inhibits Cancer Hallmarks via Targeting Aldose Reductase (AR) and Associated Signaling Network

In this current study, we demonstrated the green synthesis and characterization of silver nanoparticles using Myrtus communis L. plant extract (Ag-MC) and its evaluation of anticancer and antimicrobial activities. The green synthesis of (Ag-MC), was assessed by numerous characterization techniques such as ultraviolet-visible spectroscopy (UV-VIS), Fourier-transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD) transmission electron microscopy (TEM) and energy dispersive x-ray spectroscopy (EDX). The anti-cancer activity of the green synthesized silver nanoparticles was evaluated by the median inhibitory dose (IC50) on human liver carcinoma cell lines (HepG2). These results suggested that SN-NPs can be used as effective anticancer cell lines, as well as antibacterial and antiseptic agents in the medical field. This study showed that overexpression of aldose reductase (AR) in the human liver carcinoma cell line, HepG2, was down regulated by administration of SN-MC. The down regulation of AR was associated with abrogation of Pl3k/Akt, ERK and NF-kB pathways and the inhibition of cancer hallmarks, however, the target molecule for SN-MC was not practically established. Thus it is still unknown if the consequences were due to AR inhibition or direct Ag-MC interaction with AR.

Aldose Reductase Inhibitor, Fidarestat Prevents High-fat Diet-induced Intestinal Polyps in ApcMin/+ Mice

BACKGROUND

Recent epidemiological and experimental studies have shown that obesity is a major risk factor for Colorectal Cancer (CRC). Regular intake of high fat-containing diet can promote obesity and metabolic syndrome by increasing the insulin resistance and inflammatory response which contribute to carcinogenesis. Previously, we have shown that inhibition of polyol pathway enzyme aldose reductase (AR) prevents carcinogens- and inflammatory growth factorsinduced CRC. However, the effect of AR inhibition on a high-fat diet (HFD)-induced formation of intestinal polyps in Apc-deficient Min (multiple intestinal neoplasia; ApcMin/+) mice is not known.

METHODS

We examined the effect of AR inhibitor, fidarestat on the HFD-induced formation of preneoplastic intestinal polyps in ApcMin/+ mice which is an excellent model of colon cancer.

RESULTS

APC^Min/+ mice fed for 12 weeks of HFD caused a significant increase in the formation of polyps in the small and large intestines and fidarestat given along with the HFD prevented the number of intestinal polyps. Fidarestat also decreased the size of the polyps in the intestines of HFDtreated APC Min mice. Further, the expression levels of beta-catenin, PCNA, PKC-β2, P-AKT, Pp65, COX-2, and iNOS in the small and large intestines of HFD-treated mice significantly increased, and AR inhibitor prevented it.

CONCLUSION

Our results thus suggest that fidarestat could be used as a potential chemopreventive drug for intestinal cancers due to APC gene mutations.

Faecal microRNAs as a non-invasive tool in the diagnosis of colonic adenomas and colorectal cancer: A meta-analysis

MicroRNAs (miRNAs) are proposed as potential biomarkers for the diagnosis of numerous diseases. Here, we performed a meta-analysis to evaluate the utility of faecal miRNAs as a non-invasive tool in colorectal cancer (CRC) screening. A systematic literature search, according to predetermined criteria, in five databases identified 17 research articles including 6475, 783 and 5569 faecal-based miRNA tests in CRC, adenoma patients and healthy individuals, respectively. Sensitivity, specificity, positive/negative likelihood and diagnostic odds ratios, area under curve (AUC), summary receiver operator characteristic (sROC) curves, association of individual or combinations of miRNAs to cancer stage and location, subgroup, meta-regression and Deeks' funnel plot asymmetry analyses were employed. Pooled miRNAs for CRC had an AUC of 0.811, with a sensitivity of 58.8% (95% confidence interval [CI]: 51.7-65.5%) and specificity of 84.8% (95% CI: 81.1-87.8%), whilst for colonic adenoma, it was 0.747, 57.3% (95% CI: 40.8-72.3%) and 76.1% (95% CI: 66.1-89.4%), respectively. The most reliable individual miRNA was miR-21, with an AUC of 0.843, sensitivity of 59.3% (95% CI: 26.3-85.6%) and specificity of 85.6% (95% CI: 72.2-93.2%). Paired stage analysis showed a better diagnostic accuracy in late stage CRC and sensitivity higher in distal than proximal CRC. In conclusion, faecal miR-21, miR-92a and their combination are promising non-invasive biomarkers for faecal-based CRC screening.

The mechanisms and clinical significance of PDCD4 in colorectal cancer

In recent years, the incidence and mortality of colorectal cancer (CRC) have been on a global upward trend. There is an urgent need for effective tools to prevent and treat CRC and reduce morbidity and mortality of CRC patients. Recent evidence suggests that programmed cell death 4 (PDCD4), a novel tumor suppressor gene, inhibits tumor progression at transcriptional and translational levels and regulates multiple signal transduction pathways. However, little is known about the precise mechanisms regulating PDCD4 expression in CRC. In addition, several studies have demonstrated that the expression of in CRC is down-regulated or even absent. PDCD4 is therefore considered to be an independent prognostic factor in CRC and may be a potential support diagnostic tool for distinguishing in normal colon tissue, benign adenoma and CRC. This review will focus on the expression of PDCD4 in CRC and the relevant molecular mechanisms.

Rituximab (anti-CD20)-modified AZD-2014-encapsulated nanoparticles killing of B lymphoma cells

The mTOR signal pathway is often highly activated in B-cell non-Hodgkin's lymphoma (NHL) and promotes cancer progression and chemo-resistance. Therefore, the pathways of mTOR are an important target for drug development in this disease. In the current study, we developed a rituximab (anti-CD20)-modified mTOR inhibitor, AZD-2014, loaded into nanoparticles (Ab-NPs-AZD-2014) for trial of its anti-NHL effect. In a cultured NHL cell line, Ab-NPs-AZD-2014 inhibited cancer cell growth, induced cell apoptosis, and blocked activation of mTORC1 and mTORC2 in Raji cells. These results indicate that antibody modification and nanomaterial loading of AZD-2014 with anti-CD20 significantly improved efficacy of AZD-2014 against NHL cells. This approach may ultimately deserve testing in therapy against NHL.

Redox regulation of microRNAs in cancer

Dysregulation of microRNAs (miRNAs) has long been implicated in tumorigenesis, whereas the underlying mechanisms remain largely unknown. Oxidative stress is a hallmark of cancer that involved in multiple pathophysiological processes, including the aberrant regulation of miRNAs. Compelling evidences have implied complicated interplay between reactive oxygen species (ROS) and miRNAs. Indeed, ROS induces carcinogenesis through either reducing or increasing the miRNA level, leading to the activation of oncogenes or silence of tumor suppressors, respectively. In turn, miRNAs target ROS productive genes or antioxidant responsive elements to affect cellular redox balance, which contributes to establishing a microenvironment favoring cancer cell growth and metastasis. Both miRNAs and ROS have been identified as potential biomarkers and therapeutic targets in human malignancies, and comprehensive understanding of the molecular events herein will facilitate the development of novel cancer therapeutic strategies.

Coconut phytocompounds inhibits polyol pathway enzymes: Implication in prevention of microvascular diabetic complications

Coconut oil (CO), the primary choice of cooking purposes in the south Asian countries, is rich in medium chain saturated fatty acids, especially lauric acid (50-52%). The oil has high medicinal use in Ayurvedic system and known to contain polyphenolic antioxidants. Studies have reported that CO improves insulin sensitivity and shows hypoglycemic effect. However, there is no information regarding its effect on chronic diabetic complications including retinopathy and nephropathy is available. The secondary diabetic complications are mediated by the activation of polyol pathway, where aldose reductase (AR) plays crucial role. In this study, in silico analysis has been used to screen the effect of CO as well as its constituents, MCFAs and phenolic compounds, for targeting the molecules in polyol pathway. The study revealed that lauric acid (LA) interacts with AR and DPP-IV of polyol pathway and inhibits the activity of these enzymes. Validation studies using animal models confirmed the inhibition of AR and SDH in wistar rats. Further, the LA dose dependently reduced the expression of AR in HCT-15 cells. Together, the study suggests the possible role of CO, particularly LA in reducing secondary diabetic complications.

Opposing roles of the aldo-keto reductases AKR1B1 and AKR1B10 in colorectal cancer

PURPOSE

Aldo-keto reductases (including AKR1B1 and AKR1B10) constitute a family of oxidoreductases that have been implicated in the pathophysiology of diabetes and cancer, including colorectal cancer (CRC). Available data indicate that, despite their similarities in structure and enzymatic functions, their roles in CRC may be divergent. Here, we aimed to determine the expression and functional implications of AKR1B1 and AKR1B10 in CRC.

METHODS

AKR1B1 and AKR1B10 gene expression levels were analyzed using publicly available microarray data and ex vivo CRC-derived cDNA samples. Gene Set Enrichment Analysis (GSEA), The Cancer Genome Atlas (TCGA) RNA-seq data and The Cancer Proteome Atlas (TCPA) proteome data were analyzed to determine the effect of high and low AKR1B1 and AKR1B10 expression levels in CRC patients. Proliferation, cell cycle progression, cellular motility, adhesion and inflammation were determined in CRC-derived cell lines in which these genes were either exogenously overexpressed or silenced.

RESULTS

We found that the expression of AKR1B1 was unaltered, whereas that of AKR1B10 was decreased in primary CRCs. GSEA revealed that, while high AKR1B1 expression was associated with increased cell cycle progression, cellular motility and inflammation, high AKR1B10 expression was associated with a weak inflammatory phenotype. Functional studies carried out in CRC-derived cell lines confirmed these data. Microarray data analysis indicated that high expression levels of AKR1B1 and AKR1B10 were significantly associated with shorter and longer disease-free survival rates, respectively. A combined gene expression signature of AKR1B10 (low) and AKR1B1 (high) showed a better prognostic stratification of CRC patients independent of confounding factors.

CONCLUSIONS

Despite their similarities, the expression levels and functions of AKR1B1 and AKR1B10 are highly divergent in CRC, and they may have prognostic implications.

Aldose reductase inhibitor increases doxorubicin-sensitivity of colon cancer cells and decreases cardiotoxicity

Anthracycline drugs such as doxorubicin (DOX) and daunorubicin remain some of the most active wide-spectrum and cost-effective drugs in cancer therapy. However, colorectal cancer (CRC) cells are inherently resistant to anthracyclines which at higher doses cause cardiotoxicity. Our recent studies indicate that aldose reductase (AR) inhibitors such as fidarestat inhibit CRC growth in vitro and in vivo. Here, we show that treatment of CRC cells with fidarestat increases the efficacy of DOX-induced death in HT-29 and SW480 cells and in nude mice xenografts. AR inhibition also results in higher intracellular accumulation of DOX and decreases the expression of drug transporter proteins MDR1, MRP1, and ABCG2. Further, fidarestat also inhibits DOX-induced increase in troponin-I and various inflammatory markers in the serum and heart and restores cardiac function in mice. These results suggest that fidarestat could be used as adjuvant therapy to enhance DOX sensitivity of CRC cells and to reduce DOX-associated cardiotoxicity.

An oncogenic role of miR-592 in tumorigenesis of human colorectal cancer by targeting Forkhead Box O3A (FoxO3A)

OBJECTIVE

A microRNA (miRNA) that functionally downregulates the expression of tumor suppressors can be defined as an oncomir. Here, we interrogate the biological significance of miR-592 in colorectal cancer (CRC).

RESEARCH DESIGN AND METHODS

The expression of miR-592 in CRC tissues and cell lines was ascertained by qRT-PCR assay, and the expression of its target gene was determined by immunohistochemistry staining. The oncogenic role of miR-592 was assessed in terms of cell proliferation, migration, and clonogenicity in vitro, whereas the tumorigenicity was assessed by inhibiting endogenous miR-592 in CRC cells in vivo.

RESULTS

A striking upregulation of miR-592 was observed in CRC tissues and cell lines compared to the matched adjacent non-tumor tissues and normal colon cells. Importantly, Forkhead Box O3A (FoxO3A) was identified as a novel target of miR-592. miR-592 inhibitor exhibited a significant reduction of migration, proliferation, and clonogenicity in CRC cells. These cells also displayed a decreased tumorigenicity in SCID mice relative to the control cells.

CONCLUSION

These data suggest that miR-592 may promote the progression and metastasis, in part, by targeting FoxO3A in CRC. miR-592 may be a novel target for CRC treatment and antagomir-592 may inhibit the proliferation and metastasis of CRC cells.

Biomarkers of Angiogenesis in Colorectal Cancer

Colorectal cancer (CRC) is the third most common cancer worldwide and accounts for 10% of all new cancer diagnoses. Angiogenesis is a tightly regulated process that is mediated by a group of angiogenic factors such as vascular endothelial growth factor and its receptors. Given the widespread use of antiangiogenic agents in CRC, there has been considerable interest in the development of methods to identify novel markers that can predict outcome in the treatment of this disease with angiogenesis inhibitors. Multiple biomarkers are in various phases of development and include tissue, serum, and imaging biomarkers. The complexity of the angiogenesis pathway and the overlap between the various angiogenic factors present a significant challenge to biomarker discovery. In our review, we discuss the angiogenesis pathway and the most promising evolving concepts in biomarker discovery, as well as highlight the landmark studies that identify subgroups of patients with CRC who may preferentially benefit from angiogenesis inhibitors.

Gedunin abrogates aldose reductase, PI3K/Akt/mToR, and NF-κB signaling pathways to inhibit angiogenesis in a hamster model of oral carcinogenesis

Aberrant activation of oncogenic signaling pathways plays a central role in tumor development and progression. The aim of this present study was to investigate the chemopreventive effects of the neem limonoid gedunin in the hamster model of oral cancer based on its ability to modulate aldose reductase (AR), phosphatidyl inositol-3-kinase (PI3K)/Akt, and nuclear factor kappa B (NF-κB) pathways to block angiogenesis. Administration of gedunin suppressed the development of HBP carcinomas by inhibiting PI3K/Akt and NF-κB pathways through the inactivation of Akt and inhibitory kappa B kinase (IKK), respectively. Immunoblot and molecular docking interactions revealed that inhibition of these signaling pathways may be mediated via inactivation of AR by gedunin. Gedunin blocked angiogenesis by downregulating the expression of miR-21 and the pro-angiogenic factors vascular endothelial growth factor and hypoxia inducible factor-1 alpha (HIF-1α). In conclusion, the results of the present study provide compelling evidence that gedunin prevents progression of hamster buccal pouch (HBP) carcinomas via inhibition of the kinases Akt, IKK, and AR, and the oncogenic transcription factors NF-κB and HIF-1α to block angiogenesis.

Impact of Histone Deacetylase Inhibitors on microRNA Expression and Cancer Therapy: A Review

Chromatin-modifying drugs, such as histone deacetylase inhibitors (HDACi), have shown potential as cancer therapeutics, either alone or in combination with other therapies. HDACi have the ability to reverse aberrant epigenetic modifications associated with cancer, namely dysregulated histone acetylation. There are currently three FDA approved HDACi; vorinostat, romidepsin, and panobinostat. Epigenetic modifications can regulate the expression of protein coding genes, and in addition can alter expression of microRNA (miRNA) genes. Many miRNAs play key roles in cell proliferation and apoptosis, and are commonly dysregulated in cancer states. A number of in vitro and in vivo studies have demonstrated the ability of chromatin-modifying drugs to alter miRNA expression, which may provide the basis for further investigation of miRNAs as therapeutic targets or as biomarkers of drug response. This review summarises findings from studies investigating the effects of HDACi on miRNA expression, as well as key clinical trials involving HDACi. Understanding how chromatin-modifying drugs epigenetically modulate miRNA genes provides further insight into the cellular mechanisms that deliver therapeutic responses, and may assist in refining treatment strategies.

Activation and regulation of the granulation tissue derived cells with stemness-related properties

INTRODUCTION

Skin as the largest and easily accessible organ of the body represents an abundant source of adult stem cells. Among them, dermal stem cells hold great promise in tissue repair and the skin granulation tissue has been recently proposed as a promising source of dermal stem cells, but their biological characteristics have not been well investigated.

METHODS

The 5-bromo-2'-deoxyuridine (BrdU) lineage tracing approach was employed to chase dermal stem cells in vivo. Granulation tissue derived cells (GTCs) were isolated and their in vitro proliferation, self-renewing, migration, and multi-differentiation capabilities were assessed. Combined radiation and skin wound model was used to investigate the therapeutic effects of GTCs. MicroRNA-21 (miR-21) antagomir was used to antagonize miR-21 expression. Reactive oxygen species (ROS) were scavenged by N-acetyl cysteine (NAC).

RESULTS

The quiescent dermal stem/progenitor cells were activated to proliferate upon injury and enriched in granulation tissues. GTCs exhibited enhanced proliferation, colony formation and multi-differentiation capacities. Topical transplantation of GTCs into the combined radiation and skin wound mice accelerated wound healing and reduced tissue fibrosis. Blockade of the miR-21 expression in GTCs inhibited cell migration and differentiation, but promoted cell proliferation and self-renewing at least partially via a ROS dependent pathway.

CONCLUSIONS

The granulation tissue may represent an alternative adult stem cell source in tissue replacement therapy and miR-21 mediated ROS generation negatively regulates the stemness-related properties of granulation tissue derived cells.

Aldose reductase inhibition suppresses azoxymethane-induced colonic premalignant lesions in C57BL/KsJ-db/db mice

Type-2 diabetes and obesity-related metabolic abnormalities are major risk factors for the development of colon cancer. In the present study, we examined the effects of polyol pathway enzyme aldose reductase (AR) inhibitor, fidarestat, on the development of azoxymethane (AOM)-induced colonic premalignant lesions in C57BL/KsJ-db/db obese mice. Our results indicate that fidarestat given in the drinking water caused a significant reduction in the total number of colonic premalignant lesions in the AOM treated obese mice. Further, the expression levels of PKC-β2, AKT, COX-2 and iNOS in the colonic mucosa of AOM-treated mice were significantly decreased by fidarestat. The serum levels of IL-1α, IP-10, MIG, TNF-α and VEGF are significantly suppressed in AOM + fidarestat treated obese mice. Fidarestat also decreased the expression of COX-2, iNOS, XIAP, survivin, β-catenin and NF-κB in high glucose-treated HT29 colon cancer cells. In conclusion, our results indicate that fidarestat inhibits the development of colonic premalignant lesions in an obesity-related colon cancer and is chemopreventive to colorectal carcinogenesis in obese individuals.

MicroRNA-21 regulates biological behaviors in papillary thyroid carcinoma by targeting programmed cell death 4

BACKGROUND

Our recent study has found that microRNA-21 (miRNA-21) was significantly upregulated in papillary thyroid carcinoma (PTC) tissues compared with nontumor tissues by using miRNA microarray chip. However, the function of miRNA-21 is unknown in PTC. The aim of this study was to investigate the roles of miRNA-21 in PTC and the mechanism of gene regulation by it.

METHODS

We transfected PTC cell line (TPC-1) with pEZX-eGFP-miRNA-21 plasmid to determine the biological functions of miRNA-21. Western blot assay was applied to investigate the correlation between miRNA-21 and programmed cell death 4 (PDCD4) expression in TPC-1 cell line.

RESULTS

Overexpression of miRNA-21 could significantly enhance proliferation and invasion and inhibit the apoptosis of TPC-1 cells. In addition, miRNA-21 and PDCD4 expression showed a significantly negative correlation in TPC-1 cells.

CONCLUSIONS

These data suggest that miRNA-21 may play an oncogenic role by directly targeting PDCD4 in the cellular processes of PTC. In addition, the findings in our present study also may represent new clues for the diagnostic and therapeutic strategies in the treatment of PTC.

Elevated microRNA-31 expression regulates colorectal cancer progression by repressing its target gene SATB2

Several studies have brought about increasing evidence to support the hypothesis that miRNAs play a pivotal role in multiple processes of carcinogenesis, including cell growth, apoptosis, differentiation, and metastasis. In this study, we investigated the potential role of miR-31 in colorectal cancer (CRC) aggressiveness and its underlying mechanisms. We found that miR-31 increased in CRC cells originated from metastatic foci and human primary CRC tissues with lymph node metastases. Furthermore, the high-level expression of miR-31 was significantly associated with a more aggressive and poor prognostic phenotype of patients with CRC (p < 0.05). The stable over-expression of miR-31 in CRC cells was sufficient to promote cell proliferation, invasion, and migration in vitro. It facilitated tumor growth and metastasis in vivo too. Further studies showed that miR-31 can directly bind to the 3’untranslated region (3’UTR) of SATB2 mRNA and subsequently repress both the mRNA and protein expressions of SATB2. Ectopic expression of SATB2 by transiently transfected with pCAG-SATB2 vector encoding the entire SATB2 coding sequence could reverse the effects of miR-31 on CRC tumorigenesis and progression. In addition, ectopic over-expression of miR-31 in CRC cells induced epithelial-mesenchymal transition (EMT). Our results illustrated that the up-regulation of miR-31 played an important role in CRC cell proliferation, invasion, and metastasis in vitro and in vivo through direct repressing SATB2, suggesting a potential application of miR-31 in prognosis prediction and therapeutic application in CRC.