STIM1, a direct target of microRNA-185, promotes tumor metastasis and is associated with poor prognosis in colorectal cancer

Impact of non-coding RNAs on cancer directed immune therapies: Now then and forever

Accumulating evidence demonstrates that the host genome's epigenetic modifications are essential for living organisms to adapt to extreme conditions. DNA methylation, covalent modifications of histone, and inter-association of non-coding RNAs facilitate the cellular manifestation of epigenetic changes in the genome. Out of various factors involved in the epigenetic programming of the host, non-coding RNAs (ncRNAs) such as microRNA (miRNA), long non-coding RNA (lncRNA), circular RNA, snoRNA and piRNA are new generation non-coding molecules that influence a variety of cellular processes like immunity, cellular differentiation, and tumor development. During tumor development, temporal changes in miRNA/LncRNA rheostat influence sterile inflammatory responses accompanied by the changes in the carcinogenic signaling in the host. At the cellular level, this is manifested by the up-regulation of Inflammasome and inflammatory pathways, which promotes cancer-related inflammation. Given this, we discuss the potential of lncRNAs, miRNAs, circular RNA, snoRNA and piRNA in regulating inflammation and tumor development in the host. This article is protected by copyright. All rights reserved.

RNA N 6-Methyladenosine in Cancer Metastasis: Roles, Mechanisms, and Applications

Cancer metastasis is a symptom of adverse prognosis, a prime origin of therapy failure, and a lethal challenge for cancer patients. N⁶-methyladenosine (m⁶A), the most prevailing modification in messenger RNAs (mRNAs) and non-coding RNAs (ncRNAs) of higher eukaryotes, has attracted increasing attention. Growing studies have verified the pivotal roles of m⁶A methylation in controlling mRNAs and ncRNAs in diverse physiological processes. Remarkably, recent findings have showed that aberrant methylation of m⁶A-related RNAs could influence cancer metastasis. In this review, we illuminate how m⁶A modifiers act on mRNAs and ncRNAs and modulate metastasis in several cancers, and put forward the clinical application prospects of m⁶A methylation.

miR-185-3p targets Annexin-A8 to inhibit proliferation in cervical cancer cells

Numerous studies have found that microRNAs (miRNAs) are involved in regulating various tumor-related biological functions. The downregulation of miR185-3p have been identified in various types of cancer but the effect and its underlying molecular mechanism in cervical cancer have not been elucidated. Therefore, it is important to investigate the role of miRNAs associated with cervical cancer and its corresponding molecular mechanism to develop new therapeutic targets. The cell counting kit (CCK-8) assay was performed to measure the cell viability. The quantitative real-time PCR (qRT-PCR) and western blot analyses were carried out to identify mRNA and protein expression levels, respectively. Besides, a luciferase activity assay was conducted to confirm the target miRNA gene predictions. In this study, it is found that miR185-3p expression was potentially downregulated in cervical cancer tissues when compared with normal tissues. The CCK-8 results indicated that miR185-3p overexpression suppressed the cancer cell proliferation and the downregulation of miR185-3p enhanced the cancer cell growth. Further, enhanced miR185-3p expression led to a reduction in Annexin-A8 (Anx-A8) expression but miR185-3p inhibition promoted ANX-A8 levels in cervical cancer cells. The luciferase reporter assay indicated that ANX-A8 was a direct target of miR185-3p in cervical cancer cells.

Store-operated Ca2+ entry as a key oncogenic Ca2+ signaling driving tumor invasion-metastasis cascade and its translational potential

Tumor metastasis is the primary cause of treatment failure and cancer-related deaths. Store-operated Ca²⁺ entry (SOCE), which is mediated by stromal interaction molecules (STIM) and ORAI proteins, has been implicated in the tumor invasion-metastasis cascade. Epithelial-mesenchymal transition (EMT) is a cellular program that enables tumor cells to acquire the capacities needed for migration and invasion and the formation of distal metastases. Tumor-associated angiogenesis contributes to metastasis because aberrantly developed vessels offer a path for tumor cell dissemination as well as supply sufficient nutrients for the metastatic colony to develop into metastasis. Recently, increasing evidence has indicated that SOCE alterations actively participate in the multi-step process of tumor metastasis. In addition, the dysregulated expression of STIM/ORAI has been reported to be a predictor of poor prognosis. Herein, we review the latest advances about the critical role of SOCE in the tumor metastasis cascade and the underlying regulatory mechanisms. We emphasize the contributions of SOCE to the EMT program, tumor cell migration and invasion, and angiogenesis. We further discuss the possibility of modulating SOCE or intervening in the downstream signaling pathways as a feasible targeting therapy for cancer treatment.

Exosomal miR-128-3p Promotes Epithelial-to-Mesenchymal Transition in Colorectal Cancer Cells by Targeting FOXO4 via TGF-β/SMAD and JAK/STAT3 Signaling

Epithelial-to-mesenchymal transition (EMT) is a key process that occurs during tumor metastasis, affecting a variety of malignancies including colorectal cancer (CRC). Exosomes mediate cell-cell communication by transporting cell-derived proteins and nucleic acids, including microRNAs (miRNAs). Exosomal delivery of miRNAs plays an important role in tumor initiation, development, and progression. In this study, we investigated the effect of exosomal transfer between CRC cells and aimed to identify specific miRNAs and downstream targets involved in EMT and metastasis in CRC cells. High expression of miR-128-3p was identified in exosomes derived from EMT-induced HCT-116 cells. Altered miR-128-3p expression in CRC cells led to distinct changes in proliferation, migration, invasion, and EMT. Mechanistically, miR-128-3p overexpression downregulated the expression of FOXO4 and induced the activation of TGF-β/SMAD and JAK/STAT3 signaling in CRC cells and xenografted tumors, which led to EMT. Clinically, high expression of miR-128-3p was significantly associated with perineural invasion, lymphovascular invasion, tumor stage, and CA 19-9 content in CRC patients. We revealed that exosomal miR-128-3p regulates EMT by directly suppressing its downstream target gene FOXO4 to activate TGF-β/SMAD and JAK/STAT3 signaling, and the properties of the miR-128-3p/FOXO4 axis were horizontally transferred via exosomal delivery. In turn, exosomal miR-128-3p could be considered as a new therapeutic vehicle for CRC.

The Impact of Diet on the Involvement of Non-Coding RNAs, Extracellular Vesicles, and Gut Microbiome-Virome in Colorectal Cancer Initiation and Progression

Cancer is the major cause of morbidity and mortality in the world today. The third most common cancer and which is most diet related is colorectal cancer (CRC). Although there is complexity and limited understanding in the link between diet and CRC, the advancement in research methods have demonstrated the involvement of non-coding RNAs (ncRNAs) as key regulators of gene expression. MicroRNAs (miRNAs) which are a class of ncRNAs are key players in cancer related pathways in the context of dietary modulation. The involvement of ncRNA in cancer progression has recently been clarified throughout the last decade. ncRNAs are involved in biological processes relating to tumor onset and progression. The advances in research have given insights into cell to cell communication, by highlighting the pivotal involvement of extracellular vesicle (EV) associated-ncRNAs in tumorigenesis. The abundance and stability of EV associated ncRNAs act as a new diagnostic and therapeutic target for cancer. The understanding of the deranging of these molecules in cancer can give access to modulating the expression of the ncRNAs, thereby influencing the cancer phenotype. Food derived exosomes/vesicles (FDE) are gaining interest in the implication of exosomes in cell-cell communication with little or no understanding to date on the role FDE plays. There are resident microbiota in the colon; to which the imbalance in the normal intestinal occurrence leads to chronic inflammation and the production of carcinogenic metabolites that lead to neoplasm. Limited studies have shown the implication of various types of microbiome in CRC incidence, without particular emphasis on fungi and protozoa. This review discusses important dietary factors in relation to the expression of EV-associated ncRNAs in CRC, the impact of diet on the colon ecosystem with particular emphasis on molecular mechanisms of interactions in the ecosystem, the influence of homeostasis regulators such as glutathione, and its conjugating enzyme-glutathione S-transferase (GST) polymorphism on intestinal ecosystem, oxidative stress response, and its relationship to DNA adduct fighting enzyme-0-6-methylguanine-DNA methyltransferase. The understanding of the molecular mechanisms and interaction in the intestinal ecosystem will inform on the diagnostic, preventive and prognosis as well as treatment of CRC.

Oncogenic KRAS suppresses store-operated Ca2+ entry and ICRAC through ERK pathway-dependent remodelling of STIM expression in colorectal cancer cell lines

The KRAS GTPase plays a fundamental role in transducing signals from plasma membrane growth factor receptors to downstream signalling pathways controlling cell proliferation, survival and migration. Activating KRAS mutations are found in 20% of all cancers and in up to 40% of colorectal cancers, where they contribute to dysregulation of cell processes underlying oncogenic transformation. Multiple KRAS-regulated cell functions are also influenced by changes in intracellular Ca2+ levels that are concurrently modified by receptor signalling pathways. Suppression of intracellular Ca2+ release mechanisms can confer a survival advantage in cancer cells, and changes in Ca2+ entry across the plasma membrane modulate cell migration and proliferation. However, inconsistent remodelling of Ca2+ influx and its signalling role has been reported in studies of transformed cells. To isolate the interaction between altered Ca2+ handling and mutated KRAS in colorectal cancer, we have previously employed isogenic cell line pairs, differing by the presence of an oncogenic KRAS allele (encoding KRASG13D), and have shown that reduced Ca2+ release from the ER and mitochondrial Ca2+ uptake contributes to the survival advantage conferred by oncogenic KRAS. Here we show in the same cell lines, that Store-Operated Ca2+ Entry (SOCE) and its underlying current, ICRAC are under the influence of KRASG13D. Specifically, deletion of the oncogenic KRAS allele resulted in enhanced STIM1 expression and greater Ca2+ influx. Consistent with the role of KRAS in the activation of the ERK pathway, MEK inhibition in cells with KRASG13D resulted in increased STIM1 expression. Further, ectopic expression of STIM1 in HCT 116 cells (which express KRASG13D) rescued SOCE, demonstrating a fundamental role of STIM1 in suppression of Ca2+ entry downstream of KRASG13D. These results add to the understanding of how ERK controls cancer cell physiology and highlight STIM1 as an important biomarker in cancerogenesis.

Knockdown of stromal interaction molecule 1 inhibits proliferation of colorectal cancer cells by inducing apoptosis

Stromal interaction molecule 1 (STIM1) is an endoplasmic reticulum Ca²⁺ sensor which has been reported to be overexpressed in numerous types of cancer, and is involved in the cell proliferation, invasion, migration and metastasis frequently observed in cancer. However, the role of STIM1 in colorectal cancer (CRC) remains unknown. The purpose of the present study was to investigate the effect of STIM1 in human CRC. The expression of STIM1 was specifically knocked down using lentivirus-mediated small hairpin RNA (shRNA) interference techniques in the CRC cell lines HCT116 and SW1116. Subsequently, the efficiency of infection was confirmed using green fluorescent protein (GFP)-positive signals. The knockdown efficiency was further determined using the reverse transcription-quantitative polymerase chain reaction and western blotting analysis. As a result, CRC cell lines with STIM1 silenced were successfully constructed and subsequently employed in a series of cell function assays. Knockdown of STIM1 significantly suppressed cell proliferation and colony formation, as revealed by an MTT and colony formation assay. Furthermore, it was identified that STIM1 silencing may promote cell apoptosis through the induction of mitochondria-associated apoptosis, as was identified by increased expression levels of B-cell lymphoma 2 (Bcl-2)-associated death promoter, Bcl-2-associated X protein and poly(ADP-ribose) polymerase cleavage. Therefore, STIM1 may serve a critical role in the progression of CRC by regulating cell proliferation and apoptosis, which may provide a potential therapeutic target for the treatment of CRC.

Store operated calcium entry is altered by the inhibition of receptors tyrosine kinase

SOCE (Store-Operated Calcium Entry) is the main mechanism by which external Ca²⁺ enters into non-excitable cells after endoplasmic reticulum emptying. It is implicated in several processes such as proliferation and migration. Alterations in SOCE could initiate or support the development of hallmarks of cancer. In this project, we showed that disruption of the EGFR/ErbB2-dependent signalling by lapatinib and CP-724714, two inhibitors of the receptor tyrosine kinase (RTK), dramatically reduced the amplitude of the SOCE in breast cancer cells. LY294002 and MK2206, two inhibitors of the PI3K/Akt pathway, mimicked the effect of the inhibition of EGFR/ErbB2. In contrast, inhibitors of the MAPK pathway had no effect on SOCE. The involvement of EGFR/ErbB2 receptors and the PI3K/Akt pathway in the regulation of SOCE was confirmed in other cell lines derived from various cancer types. All these results showed that SOCE is positively regulated by the PI3K/Akt pathway and that this effect may be suppressed by the inhibition of the upstream RTKs. Inhibition of SOCE might therefore contribute to the anticancer effects of RTK inhibitors.

STIM1 and STIM2 differently regulate endogenous Ca2+ entry and promote TGF-β-induced EMT in breast cancer cells

The Ca²⁺ sensor proteins STIM1 and STIM2 are crucial elements of store-operated calcium entry (SOCE) in breast cancer cells. Increased SOCE activity may contribute to epithelial-mesenchymal transitions (EMT) and increase cell migration and invasion. However, the roles of STIM1 and STIM2 in TGF-β-induced EMT are still unclear. In this study, we demonstrate roles of STIMs in TGF-β-induced EMT in breast cancer cells. In particular, STIM1 and STIM2 expression affected TGF-β-induced EMT by mediating SOCE in MDA-MB-231 and MCF-7 breast cancer cells. The specific SOCE inhibitor YM58483 blocked TGF-β-induced EMT, and differing effects of STIM1 and STIM2 on TGF-β-induced EMT correlated with differing roles in SOCE. Finally, we showed that STIM2 is associated with non-store-operated calcium entry (non-SOCE) during TGF-β-induced EMT, whereas STIM1 is not. What's more, non-SOCE have a large possibility to be ROCE. In conclusion, STIM1 and STIM2 proteins play important roles in TGF-β-induced EMT and these effects are related to both SOCE and non-SOCE.

miR-185-3p regulates the invasion and metastasis of nasopharyngeal carcinoma by targeting WNT2B in vitro

MicroRNAs (miRs) have been recognised as important regulators of malignant behaviour in different types of human cancer, including nasopharyngeal carcinoma (NPC). A previous study by our group revealed that miR-185-3p regulates the radioresistance of NPC cells. The present study aimed to investigate the effect of miR-185-3p on NPC invasion and metastasis. Human NPC CNE-2 and 5-8F cell lines were transfected with a miR-185-3p mimic and miR-185-3p inhibitor, respectively, and their effects on the invasion and metastasis of these cells was assessed using a wound healing assay and Matrigel invasion assay. The target gene of miR-185-3p, Wnt family member 2B (WNT2B) was silenced in 5-8F cells using siRNA in order to investigate its function in NPC. Data from the present study demonstrated that the expression of miR-185-3p was the highest in 5-8F and lowest in CNE-2 cells out of a range of NPC cell lines. Following the transfection of miR-185-3p mimic into CNE-2 cells, the wound healing and Matrigel invasion assays indicated that the migration and invasion ability of CNE-2 cells was significantly reduced compared with the negative control group. In addition, the inhibition of miR-185-3p in 5-8F cells significantly increased the capacity for migration and invasion. Furthermore, silencing WNT2B expression resulted in a significant reduction in the invasion and metastasis in 5-8F cells. The inhibition of miR-185-3p, which promotes invasion and metastasis, could be reversed through the silencing of WNT2B in 5-8F cells. The results of the present study indicate that miR-185-3p mediates the invasion and metastasis of NPC by targeting WNT2B in vitro.

MiRNA-based therapeutic intervention of cancer

MicroRNAs (miRNAs) are important modulators of eukaryotic gene expression. By targeting protein coding transcripts, miRNAs influence the cellular transcriptome and proteome, thus helping to determine cell fate. MiRNAs have emerged as crucial molecules in cancer research, in which recent studies have linked erratic expression of miRNAs to carcinogenesis and have provided solid evidence for their potential in cancer therapy. This review briefly summarises the recent knowledge on the involvement of miRNAs in tumourigenesis and reviews current studies on the therapeutic strategies and advances in the delivery of miRNAs.