Hyaluronic acid-decorated liposomal nanoparticles for targeted delivery of 5-fluorouracil into HT-29 colorectal cancer cells.

The use of liposomes as drug carriers improves the therapeutic efficacy of anticancer drugs, while at the same time reducing side effects. Hyaluronic acid (HA) is recognized by the CD44 receptor, which is overexpressed in many cancer cells. In this study, we developed HA-modified liposomes encapsulating 5-fluorouracil (5-FU) and tested them against a CD44 expressing colorectal cell line (HT29) and a non-CD44 expressing hepatoma cell line. The average size of 5-FU-lipo and 5-FU-lipo-HA nanoparticles were 112 ± 28 and 144 ± 77 nm, respectively. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assay showed selective cancer cell death depending on the CD44 expression in a time-dependent manner. Apoptosis assays and cell-cycle analysis indicated that G0/G1 arrest occurred. The colony formation study revealed that cells treated with 5-FU-lipo and 5-FU-lipo-HA had reduced colony formation. Quantitative reverse-transcription polymerase chain reaction study showed that the oncogenic messenger RNA and microRNA levels were significantly reduced in the 5-FU-lipo-HA-treated group, while tumor suppressors were increased in that group. We suggest that optimal targeted delivery and release of 5-FU into colorectal cancer cells, renders them susceptible to apoptosis, cell-cycle arrest, and decreased colony formation.

The effect of combined miR-200c replacement and cisplatin on apoptosis induction and inhibition of gastric cancer cell line migration.

One of the major obstacles in the treatment of cancer is resistance to standard chemotherapeutic drugs. According to the numerous reports, miR-200c is involved in many cancers, especially gastric cancer, and also miR-200c has been known as an effective factor in the elimination of chemotherapy resistance. The purpose of this study was to explore the potential function and mechanism of miR-200c and cisplatin in the inhibition of migration and induction of apoptosis in gastric cancer cells. In this study, first, miR-200c mimics and LNA-anti-miR-200c were transfected into KATOIII cells. Moreover, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay results revealed that increased miR-200c expression and cisplatin can more inhibited the proliferation of KATOIII cells. MiR-200c overexpression inhibited the movement of KATOIII cells in wound healing assay. Subsequently, miR-200c/cisplatin could suppress colony formation in KATOIII cells. To identify a potential miR-200c target, we investigated the effect of miR-200c modulation on RhoE, PTEN, VEGFR, and MMP9 expression levels. Increased miR-200c expression caused a reduction in VEGFR and MMP9 mRNA and protein, suggesting that VEGFR and MMP9 are targets of miR-200c. In addition, reverse-transcription polymerase chain reaction assays showed that RhoE is target gene of miR-200c and LNA-anti-miR-200c suppressed the expression of PTEN. Flow cytometry and 4',6-diamidino-2-phenylindole staining analysis indicated that miR-200c increased the cisplatin-induced apoptosis which may be associated with suppression of RhoE expression in KATOIII cells, also cell-cycle analysis showed the arrest of cell-cycle progression at the G2 phase. These data demonstrated that miR-200c functioned as a suppressor gene in KATOIII cells. Also, miR-200c can be a potential therapeutic approach to overcome chemoresistance during cisplatin chemotherapy.

miR-142-3p as tumor suppressor miRNA in the regulation of tumorigenicity, invasion and migration of human breast cancer by targeting Bach-1 expression.

BACKGROUND: Breast cancer is the most common type of cancer among women, and despite improved treatments, it remains a major challenge. However, improved mechanistic insight may lead to novel therapeutic strategies. miR-142-3p belongs to the miR-142 family and is involved in pathogenesis and metastasis of various types of malignancies by targeting several important messenger RNAs (mRNAs) including Bach-1. This is especially true for breast cancer, where Bach-1 is involved in the metastatic spread by deregulation of metastasis-associated genes. METHODS: In this study, we collected 24 breast cancer tissues with 24 adjusted normal tissues to measure the expression levels of miR-142-3p and Bach-1 mRNA using quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and IHC. miR-142-3p targeting of Bach-1 expression in MCF-7 and MDA-MB-468 breast cancer cells was evaluated using bioinformatics, qRT-PCR and western blot analyses. The cellular proliferation, invasion, and migration were assessed by MTT, transwell matrigel and wound healing assay and the EMT-associated proteins C-X-C chemokine receptor type 4 (CXCR-4), matrix metalloproteinase-9 (MMP9), and vascular endothelial growth factor receptor (VEGFR) were analyzed by western blot analysis. Also, the expression levels of tumor suppressors including miR-330, miR-145, and miR-34a were estimated by qRT-PCR. RESULTS: Analysis of paired specimens of primary malignant and normal tissues showed that miR-142-3p was downregulated, while Bach-1 mRNA and protein both were overexpressed in the breast cancer tumors. This inverse relationship was confirmed by cell line experiments demonstrating that miR-142-3p expression reduced Bach-1 mRNA levels. Furthermore, replacement of miR-142-3p could inhibit the proliferation, invasion, and migration in breast cancer potentially by targeting of Bach-1 mRNA and subsequent inhibition of CXCR4, MMP9, and VEGFR protein expressions. In addition, induction of miR-142-3p could upregulate tumor suppressor miRNAs, including miR-330, miR-145, and miR34a. CONCLUSION: For the first time, our results revealed that miR-142-3p could target Bach-1in breast cancer cells leading to the reduction of EMT-related proteins and reduced cell proliferation, invasion, and migration. The results also demonstrated that miR-142-3p could regulate important tumor suppressor miRNAs in breast cancer cells. In conclusion, our results suggest that miR-142-3p could be a good candidate for the targeted therapy of breast cancer, especially for the invasive type.

MicroRNAs in cancer drug resistance: Basic evidence and clinical applications.

Development of drug resistance has considerably limited the efficacy of cancer treatments, including chemotherapy and targeted therapies. Hence, understanding the molecular mechanisms underpinning the innate or the acquired resistance to these therapies is critical to improve drug efficiency and clinical outcomes. Several studies have implicated microRNAs (miRNA) in this process. MiRNAs repress gene expression by specific binding to complementary sequences in the 3' region of target messenger RNAs (mRNAs), followed by target mRNA degradation or blocked translation. By targeting molecules specific to a particular pathway within tumor cells, the new generation of cancer treatment strategies has shown significant advantages over conventional chemotherapy. However, the long-term efficacy of targeted therapies often remains poor, because tumor cells develop resistance to such therapeutics. Targeted therapies often involve monoclonal antibodies (mAbs), such as those blocking the ErB/HER tyrosine kinases, epidermal growth factor receptor (cetuximab) and HER2 (trastuzumab), and those inhibiting vascular endothelial growth factor receptor signaling (e.g., bevacizumab). Even though these are among the most used agents in tumor medicine, clinical response to these drugs is reduced due to the emergence of drug resistance as a result of toxic effects in the tumor microenvironment. Research on different types of human cancers has revealed that aberrant expression of miRNAs promotes resistance to the aforementioned drugs. In this study, we review the mechanisms of tumor cell resistance to mAb therapies and the role of miRNAs therein. Emerging treatment strategies combine therapies using innovative miRNA mimics or antagonizers with conventional approaches to maximize outcomes of patients with cancer.

Downregulation of miR-146a promotes cell migration in Helicobacter pylori-negative gastric cancer.

microRNAs (miRs) are short noncoding RNAs that post-transcriptionally suppress gene expression. miR-146a acts as an oncogene or a tumor suppressor in various cancers, including gastric cancer, but it is unclear what determines whether miR-146a is oncogenic or tumor suppressive and the molecular mechanisms are still largely unknown. The aim of this study was to investigate the role of miR-146a in gastric cancer, by focusing on its expression in patients who were negative for Helicobacter pylori and its reduced and increased expression effect in vitro. Twenty gastric cancer patients who were negative for H. pylori infection were selected and the expression levels of miRNA-146a in these gastric tumors, in their matched normal gastric tissues and in gastric cancer cell lines with varying tumorigenic potential was measured. Further, the impact of increased and decreased miR-146a expression levels on the expression of predicted target genes, cell migration, viability, proliferation, and apoptosis was examined, respectively. Our results for the first time indicated that miR-146a is downregulated in H. pylori-negative gastric cancers and suggests that H. pylori infection determines whether miR-146a acts as an oncogene or tumor suppressor. The level of miR-146a expression inversely correlates with the tumorigenicity of three gastric cancer cell lines and low miR-146a expression predicts poor recurrence-free survival. It was also found that miR-146a reduces the expression levels of the prometastatic genes and suppresses MKN-45 cell migration. Functional studies showed that miR-146a acts as a tumor suppressor miR and identifies miR-146a as a candidate for antimetastatic miRNA replacement therapy for gastric cancer patients.

microRNA-193a-5p inhibits migration of human HT-29 colon cancer cells via suppression of metastasis pathway.

PURPOSE: Altered expression of microRNAs (miRNAs) is indicated strongly in colorectal cancer (CRC). This study aims to evaluate the inhibitory role of miR-193a-5p on epithelial-mesenchymal transition markers in CRC lines. The cellular effects and potential mechanisms of miR-193a-5p were also examined. METHODS: Quantitative reverse-transcription polymerase chain reaction (RT-PCR) was performed to determine the expression of miR-193a-5p in three CRC cell lines (HCT-116, SW-480, and HT-29) and its impact on metastasis-related genes ( vimentin and CXCR4) before and after mimic transfection. Of those, the cell line with the highest changes was selected for the next upcoming experiments such as wound-healing assay, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), and annexin-V staining tests. RESULTS: Our results revealed that miR-193a-5p was significantly downregulated in three CRC cell lines and that HT-29 displayed the most decrease ( P < 0.0001). The restoration of miR-193a-5p in human HT-29 cell line inhibited cell migration. But, miR-193a-5p transfection did not affect cell viability and had no significant effect on apoptosis induction. Also, the quantitative RT-PCR analysis of miR-193a-5p mimic transfected cells revealed a significant increase in miR-193a-5p messenger RNA (mRNA) expression level ( P < 0.0001) with reduction of vimentin and CXCR4 mRNA expression levels in HT-29 cell line ( P < 0.01 and < 0.05, respectively). CONCLUSION: Our results indicated that miR-193a-5p acts as a tumor suppressor miRNA and its downregulation plays an important role in metastasis via upregulation of metastasis-related genes in CRC. Therefore, it can be considered as a potential therapeutic target for applying in CRC management in the future.

MiR-146a functions as a small silent player in gastric cancer.

Gastric cancer is responsible for approximately one million annual deaths worldwide. Recently, the important roles of miRNAs as vital factors in malignancy processes such as metastasis have identified. They involve in the regulation of different biological procedures such as proliferation, invasion, metastasis and cell survival. MiR-146a has an aberrant expression in different tumors and has different expressions in the gastric cancer cell lines. This microRNA can act as a tumor suppressor and/or oncogene in gastric cancer related cases. Most of the studies have confirmed that miR-146a is downregulated in human gastric cancer cell lines and tissues, significantly and that it has tumor suppressor effects in gastric cancers. On the other hand, the role of miR-146a as an oncogene has been studied in an in-vitro experiment and results showed that over- an expression of miR-146a in gastric cancer tissues inhibits apoptosis and improves cell proliferation of gastric cancer cell. MiR-146a also has been a candidate for diagnosis and prognosis in gastric cancer cases. In this review, we focus on the important roles of miR-146a in tumor genesis of gastric tissues, emphasizing on the involvement of this microRNA in diagnosis, prognosis, chemotherapy response and finally, potential therapeutic applications as an anticancer agent in inhibition of gastric cancer cell metastasis and invasion.