Tumor Suppressor In Colon Cancer Research Articles

SIRT6 suppresses colon cancer growth by inducing apoptosis and autophagy through transcriptionally down-regulating Survivin

SIRT6, an evolutionarily conserved histone deacetylase, has been identified as a novel direct downstream target of Akt/FoxO3a and a tumor suppressor in colon cancer in our previous research. Nevertheless, the precise mechanisms through which SIRT6 hinders tumor development remain unclear. To ascertain whether SIRT6 directly impacts Survivin transcription, a ChIP assay was conducted using an anti-SIRT6 antibody to isolate DNA. YM155 was synthesized to explore Survivin’s role in mitochondrial apoptosis, autophagy and tumor progression. Our investigation into the regulation of Survivin involved real-time fluorescence imaging in living cells, real-time PCR, immunohistochemistry, flow cytometry, and xenograft mouse assays. In this current study, we delved into the role of SIRT6 in colon cancer and established that activated SIRT6 triggers mitochondrial apoptosis by reducing Survivin expression. Subsequent examinations revealed that SIRT6 directly binds to the Survivin promoter, impeding its transcription. Notably, direct inhibition of Survivin significantly impeded colon cancer proliferation by inducing mitochondrial apoptosis and autophagy both in vitro and in vivo. More interestingly, Survivin inhibition reactivated the Akt/FoxO3a pathway and elevated SIRT6 levels, establishing a positive feedback loop. Our results identify Survivin as a novel downstream transcriptional target of SIRT6 that fosters tumor growth and holds promise as a prospective target for colon cancer therapy.

DNASE1L3 enhances antitumor immunity and suppresses tumor progression in colon cancer.

DNASE1L3, an enzyme highly expressed in DCs, is functionally important for regulating autoimmune responses to self-DNA and chromatin. Deficiency of DNASE1L3 leads to development of autoimmune diseases in both humans and mice. However, despite the well-established causal relationship between DNASE1L3 and immunity, little is known about the involvement of DNASE1L3 in regulation of antitumor immunity, the foundation of modern antitumor immunotherapy. In this study, we identify DNASE1L3 as a potentially new regulator of antitumor immunity and a tumor suppressor in colon cancer. In humans, DNASE1L3 is downregulated in tumor-infiltrating DCs, and this downregulation is associated with poor patient prognosis and reduced tumor immune cell infiltration in many cancer types. In mice, Dnase1l3 deficiency in the tumor microenvironment enhances tumor formation and growth in several colon cancer models. Notably, the increased tumor formation and growth in Dnase1l3-deficient mice are associated with impaired antitumor immunity, as evidenced by a substantial reduction of cytotoxic T cells and a unique subset of DCs. Consistently, Dnase1l3-deficient DCs directly modulate cytotoxic T cells in vitro. To our knowledge, our study unveils a previously unknown link between DNASE1L3 and antitumor immunity and further suggests that restoration of DNASE1L3 activity may represent a potential therapeutic approach for anticancer therapy.

MiR-3133 is an unfavorable prognosis factor and tumor suppressor in colon cancer.

Dysregulated miRNAs have been demonstrated to be associated with the progression of colon cancer. The dysregulation of miR-3133 was observed in colon cancer, but its specific function was unclear. The functional role of miR-3133 in colon cancer was investigated in this study. A total of 113 colon cancer patients were included. miR-3133 expression was evaluated by PCR. The biological effects of miR-3133 in colon cancer cells were assessed with the help of the transwell and CCK8 assay. The prognostic value of miR-3133 was estimated by a series of statistical analyses. In mechanism, the interaction between miR-3133 and RUFY3 was evaluated by luciferase reporter. The significant downregulation of miR-3133 was observed in colon cancer, which showed a significant association with the advanced TNM stage and bad survival of patients. miR-3133 and TNM stage were identified as independent prognostic indicators of colon cancer. In vitro, the overexpression of miR-3133 exerted a dramatically inhibitory effect on cellular processes of colon cancer, which were enhanced by miR-3133 knockdown. Additionally, miR-3133 could negatively regulate the luciferase activity and expression of RUFY3, which was speculated as the underlying mechanism mediating the regulatory effect of miR-3133. miR-3133 functioned as a prognostic biomarker indicating the progression and prognosis of colon cancer, and it also served as a tumor suppressor via negatively regulating RUFY3, which provides a potential therapeutic target for colon cancer.

Role of CDX2 Marker in Patients with Colorectal Cancer

CDX2 has been proposed as a tumor suppressor in colon cancer, CDX2 gene is often amplified in colon cancer, there is a lineage survival oncogene function in some tumors, the role of CDX2 protein during CRC development remains debatable. The aim of this study investigate the effect of low CDX2 expression on overall survival (OS) for prognosis of CRC patients and estimate of therapeutic activity of CDX2 expression in predictive of chemotherapy respond. This study done in the Middle Euphrates Unit for Cancer Research, Faculty of Medicine, University of Kufa in Al-Najaf province. This study was carried out on sixty-three cases of CRC in the form of available paraffin blocks who underwent surgical resection between 2015 and 2020. Thirty_ seven blocks of normal non tumoral colorectal tissue collected randomly from archives of two private laboratories during collection of malignant tissue blocks. Nuclear low expression of CDX2 in control and patient groups were 0(0.00%) and 30 (47.6%), while high expression of this protein was 37 (100%) and 33(52.4%) in control and patient groups respectively. OS was longer in patients with low CDX2 protein expression who intake adjuvant chemotherapy (71.33%) with mean survival (24.75±2.81 month) than patients were not intake adjuvant chemotherapy (53.71%) with mean survival (15.227±1.66 month). CDX2 expression regarded as diagnostic marker for non-mucinous CRC. High of CDX2 expression can be used as an independent good prognostic biomarker to predict longer survival of patients with CRC.

The emerging role of miR-20b in human cancer and other disorders: Pathophysiology and therapeutic implications.

miR-20b is a microRNA with diverse and somehow contradictory roles in the pathogenesis of human disorders, especially cancers. It has been known to be a tumor suppressor in colon cancer, renal cell carcinoma, prostate cancer, osteosarcoma and papillary thyroid cancer. In lung cancer and breast cancers, both tumor suppressor and oncogenic effects have been identified for this miRNA. Finally, in T cell leukemia, hepatocellular carcinoma, esophageal squamous cell carcinoma and cervical and gastric cancers, miR-20b is regarded as an oncogenic miRNA. In several types of cancer, dysregulation of miR-20b has been recognized as a predictive marker for patients' survival. Dysregulation of miR-20b has also been recognized in Alzheimer's disease, diabetic retinopathy, myocardial ischemia/infarction, chronic hepatitis B and multiple sclerosis. In the current review, we have summarized the miR-20b targets and related cellular processes. We have also provided a review of participation of this miRNA in different human disorders.

MiR-372-3p Functions as a Tumor Suppressor in Colon Cancer by Targeting MAP3K2.

MicroRNAs (miRNAs) as small non-coding RNA transcripts bind their complementary sequences in the 3′-untranslated region (3′-UTR) of target messenger RNAs (mRNAs) to regulate their expression. It is known that miR-372 belongs to the miR-371–373 gene cluster and has been found to be abnormally expressed in a variety of cancers, but its precise mechanism in cancer remains to be discovered. In this study, miR-372-3p expression was assessed in 153 frozen tissue samples, including primary diagnosed colon cancer and matched normal and adjacent tissues, using real time quantitative polymerase chain reaction (qPCR). An analysis of qPCR data revealed a significant reduction in miR-372-3p expression (by >2-fold) in colon cancer tissues in 51.5% (34/66) of patients. Consistent with this, mimicking the increased miR-372-3p levels in SW480 colon cancer cells significantly suppressed cell growth and proliferation. Although no direct correlation was found between the low level of miR-372-3p and certain tumor-related factors, such as p53, HRE-2, PMS2, MLH1, MSH2, MSH6, HDAC4, p21, and Wee1, in colon cancer tissues, an inverse relationship between miR-372-3p and Ki67 (a marker of proliferation) or miR-372-3p and MAP3K2(MEKK2), which plays a critical role in the MAPK signaling pathways, was confirmed using tissue samples. The target relationship between miR-372-3p and MAP3K2 was verified using luciferase assays in SW480 colon cancer cells. As expected, miR-372-3p mimics significantly suppressed the luciferase activity of pMIR-luc/MAP3K2 3′-UTR in cells, suggesting that miR-372-3p modulates the expression of MAP3K2 by directly targeting its 3′-UTR. Overall, the results obtained herein suggest that miR-372-3p may function as a tumor-suppressor miRNA in colon cancer by targeting MAP3K2.

Curcumin Synergizes with Cisplatin to Inhibit Colon Cancer through Targeting the MicroRNA-137-Glutaminase Axis.

Colorectal cancer (CRC) is one of the most lethal and prevalent malignancies world-wide. Currently, surgery, radiotherapy and chemotherapy are clinically applied as common approaches for CRC patients. Cisplatin is one of the most frequently used chemotherapy drugs for diverse cancers. Although chemotherapeutic strategies have improved the prognosis and survival of cancer patients, development of cisplatin resistance has led to cancer recurrence. Curcumin, isolated from turmeric, has been used as an effective anti-cancer agent. However, the molecular mechanisms for curcumin-mediated cisplatin sensitivity of CRC have not been elucidated. This study aimed to investigate the effects of curcumin treatment on cisplatin-resistant CRC cells. Expression levels of miRNAs and mRNAs were determined by qRT-PCR. Protein expression levels were detected by Western blotting. Cell responses to curcumin treatments were evaluated by MTT assay, Clonogenic assay and Annexin V apoptosis assay. The glutamine metabolism of colon cancer cells was assessed by glutamine uptake and glutaminase (GLS) activity. The binding of miR-137 on 3' UTR of GLS was validated by Western blotting and luciferase assay. Results demonstrated that curcumin significantly synergized with cisplatin (combination index <1) to suppress proliferation of colon cancer cells compared with curcumin or cisplatin alone. Moreover, from the established cisplatin-resistant cell line (HT-29), glutamine metabolism was remarkedly elevated in cisplatin-resistant CRC cells that displayed a glutamine addictive phenotype. Furthermore, curcumin treatments attenuated glutamine metabolism in colon cancer cells. Under low glutamine supply, colon cancer cells showed less sensitivity to curcumin. Using a microRNA (miRNA) microArray assay, miR-137, a tumor suppressor in colon cancer, was significantly induced by curcumin treatments in CRC cells. Bioinformatics analysis and a luciferase assay illustrated miR-137 directly targeted the 3' UTR of GLS mRNA. Rescue experiments demonstrated that miR-137-induced cisplatin sensitization was through targeting of GLS. Finally, curcumin treatment overcame cisplatin resistance through miR-137-mediated glutamine inhibition. Collectively, these results indicate that curcumin could be clinically applied as an anti-chemoresistance approach against CRC by modulating miR-137-inhibited glutamine metabolism.

MicroRNA miR-145-5p regulates cell proliferation and cell migration in colon cancer by inhibiting chemokine (C-X-C motif) ligand 1 and integrin α2

ABSTRACT Colon cancer (CC), which has high morbidity and mortality, can be regulated by microRNAs. This study aimed to investigate the regulatory function of microRNA miR-145-5p in CC cells. Bioinformatics analysis was used to screen key genes in CC. The expression of miR-145-5p, chemokine (C-X-C motif) ligand 1 (CXCL1), and integrin α2 (ITGA2) in CC was confirmed by quantitative reverse transcription polymerase chain reaction and western blotting. After cell transfection, changes in proliferation and migration in CC cells were detected using the cell counting kit-8 (CCK-8), colony formation assay, and wound healing assay. A luciferase assay was conducted to confirm the interactome of miR-145-5p, CXCL1, and ITGA2 in CC cells. Bioinformatics analysis confirmed that CXCL1 and ITGA2 were key genes in CC. After performing several cell functional experiments, the results confirmed that upregulation of miR-145-5p attenuated proliferation and migration of CC cells. Luciferase assay and western blotting confirmed that CXCL1 and ITGA2 were targets of miR-145-5p, and their expression in CC could be suppressed by miR-145-5p. In conclusion, miR-145-5p is a tumor suppressor in CC and can inhibit the expression of CXCL1 and ITGA2.

MiR-1236-3p Inhibits the Proliferation, Invasion, and Migration of Colon Cancer Cells and Hinders Epithelial-Mesenchymal Transition by Targeting DCLK3.

BackgroundDysregulated microRNAs (miRNAs) are common in human cancer and are involved in the proliferation, promotion, and metastasis of tumor cells. Therefore, this study aimed to evaluate the expression and biological function of miR-1236-3p in colon cancer.MethodsThis study screened the miRNA in normal and colon cancer tissues through array analysis. In addition, quantitative Reverse Transcription–Polymerase Chain Reaction (qRT-PCR) analysis was performed to validate the expression of miR-1236-3p in normal and tumor tissues from colon cancer patients and cancer cell lines. Online predicting algorithms and luciferase reporter assays were also employed to confirm Doublecortin Like Kinase 3 (DCLK3) was the target for miR-1236-3p. Moreover, the impact of miR-1236-3p on the progression of colon cancer was evaluated in vitro and in vivo. Western blotting and qRT-PCR were also performed to investigate the interactions between miR-1236-3p and DCLK3.ResultsMiR-1236-3p was significantly downregulated in colon cancer tissues and its expression was associated with the TNM stage and metastasis of colon. In addition, the in vitro and in vivo experiments showed that miR-1236-3p significantly promoted cancer cell apoptosis and inhibited the proliferation, invasion, and migration of cancer cells. The results also showed that miR-1236-3p hindered Epithelial–mesenchymal Transition (EMT) by targeting DCLK3. Moreover, the expression of DCLK3 mediated the effects of miR-1236-3p on the progression of cancer.ConclusionsMiR-1236-3p functions as a tumor suppressor in colon cancer by targeting DCLK3 and is therefore a promising therapeutic target for colon cancer.

Human α-defensin 5 suppressed colon cancer growth by targeting PI3K pathway

Defensins are highly conserved antimicrobial peptides, which ubiquitously expressed in different species. In addition to the functions in host defense, their aberrant expression have also been documented in cancerous tissue including breast cancer, lung caner and renal carcinoma etc. Whereas, roles of Defensin Alpha 5 (DEFA5) in colon cancer has not been explored. Bioinformatic analysis was used to study the expression of DEFA5 and its correlation with clinical outcomes; Western blot, qPCR, Co-immunoprecipitation, xenograft models were used to the study the molecular mechanism. Decreased expression of DEFA5 at protein level was observed in colon tissues. Colon cancer cell lines proliferation and colony formation capacity were significantly suppressed by DEFA5 overexpression. Moreover, in vivo tumor growth in nude mice was also suppressed by DEFA5 overexpression, suggesting a tumor suppressor role of DEFA5 in colon cancer. Mechanistically, DEFA5 directly binds to the subunits of PI3K complex, thus attenuates the downstream signaling transduction, leads to delayed cell growth and metastasis. Collectively, we concluded that DEFA5 showed an inhibitory effect in colon cancer cell growth and may serve as a potential tumor suppressor in colon cancer.

MiR-20b-5p functions as tumor suppressor microRNA by targeting cyclinD1 in colon cancer

ABSTRACT MicroRNA functions as an oncogenic regulator or tumor suppressor in various human tumors. Although bioinformatics analysis suggested that miRNA-20b-5p may be associated with the tumorigenesis, its role in colon cancer remains elusive. To investigate the role of miRNA-20b-5p, HCT116 cell, a human colon cancer cell line used in therapeutic research and drug screenings, was chosen as a model system for our in vitro studies. We first carried out bioinformatics and microarray analysis. To gain further mechanism insight, flow cytometry was performed to determine cell apoptosis and cell cycle, and western blot or immunohistochemistry were employed to check the expression of CCND1/CDK/FOXM1 axis in HCT116 cells. In addition, wound-healing migration assay and transwell assay were conducted to uncover the effect of miR-20b-5p on tumor migration and invasion. Finally, we examined the role of miR-20b-5p by subcutaneous xenograft mouse models. Our data have shown that miRNA-20b-5p inhibited the cell cycle, migration, and invasion in HCT116 cells, but had no effect on cell apoptosis. CyclinD1 (CCND1) was identified as a direct target of miR-20b-5p. Overexpression of miRNA-20b-5p downregulated CCND1 level in HCT-116 cells. Mechanically, the inhibition of cell cycle, migration, and invasion of CC cells mediated by miRNA-20b-5p are through regulating the CCND1/CDK4/FOXM1 axis. Furthermore, miRNA-20b-5p inhibited the tumorigenesis in Balb/c nude mice CC xenograft models. Our data demonstrated that miR-20b-5p may serve as a tumor suppressor in colon cancer by negatively regulating CCND1, implying that miR-20b-5p could be a potential therapeutic target for the treatment of colon cancer.

USP46 Inhibits Cell Proliferation in Lung Cancer through PHLPP1/AKT Pathway.

Previous studies have shown that ubiquitin-specific protease 46 (USP46) is a tumor suppressor in colon cancer and renal cell carcinoma. However, its specific role in other cancers is still poorly understood. This study is aimed at investigating the role of USP46 in lung cancer tumorigenesis and identifying its underlying mechanisms. Quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting (WB) were used to measure the expression levels of USP46 and PHLPP1 in lung cancer tissue and adjacent normal tissue from patients with lung cancer. We examined the ability of USP46 to regulate cell proliferation in lung cancer cells via cell proliferation assay, radiation assay, genetic overexpression and knockdown, and chemical inhibition of relevant genes. We investigated the underlying mechanisms in multiple lung cancer cell line models by coimmunoprecipitation and ubiquitination assays. In this study, we identified a strong downregulation of the expressions of USP46 and PHLPP1 in lung cancer tissues relative to normal adjacent tissues. USP46 was further shown to inhibit lung cancer cell proliferation under conditions of normal growth and during radiation-induced DNA damage by antagonizing the ubiquitination of PHLPP1 resulting in the inhibition of AKT signaling. Exposure to radiation and AKT inhibition significantly reversed the effect of USP46 siRNA on lung cancer cell proliferation. USP46 is downregulated in lung cancer and suppresses the proliferation of lung cancer cells by inhibiting the PHLPP1/AKT pathway. AKT inhibition slows the proliferation of lung cancer cells that have been downregulated by USP46 and exposed to radiation. This suggests a potential therapeutic avenue for USP46-downregulated lung cancer through a combination of radiation and AKT inhibitor treatment.

A novel epigenetic regulation of circFoxp1 on Foxp1 in colon cancer cells

Foxp1 is a tumor suppressor in colon cancer. However, circFoxp1 derived from Foxp1 is an oncogene. In this study, we aim to investigate the role of circFoxp1 in colon cancer and the regulatory mechanism between circFoxp1 and Foxp1. 78 human colon tumor tissues and the matched paracancerous tissues were collected. Quantitative polymerase chain reaction, immunohistochemistry, quantitative methylation-specific PCR, chromatin immunoprecipitation assay, CCK-8 assay, and Tumor xenograft in nude mice were performed. The expression of circFoxp1 was increased and Foxp1 was reduced in colon cancer tissues, which were associated with a poor overall survival rate of the patients with colon cancer. CircFoxp1 recruited DNMT1 to the promoter of Foxp1, leading to promotor hypermethylation, thereby inhibiting Foxp1 transcription. Interfering circFoxp1 by siRNA in SW620 cells significantly inhibited cell viability, while knockdown Foxp1 expression partially restored SW620 cell viability. In addition, knockdown of circFoxp1 significantly sensitized colon cancer cells to Capecitabine in vitro and vivo through regulating Foxp1. We discovered a novel epigenetic pathway that circFoxp1 regulated Foxp1 in colon cancer cells. CircFoxp1 may regulate DNA methylation and demethylation to coordinate colon cancer cell proliferation and participate in chemotherapy drug responses. Therefore, circFoxp1 may be a potential therapeutic target for colon cancer.

PHLPP2 is regulated by competing endogenous RNA network in pathogenesis of colon cancer

Recently, homologous pleckstrin-homology (PH)-domain leucine-rich-repeat protein phosphatases (PHLPP2) has been reported as a tumor suppressor in colon cancer. This study aimed to unravel the possible involvement of long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) regulating PHLPP2 in colon cancer. Expressions of candidate lncRNAs and miRNAs were verified by the RT-qPCR and Western blot analyses in colon cancer. The roles of candidate genes in colon cancer were investigated in HT-29 cells in vitro and in mouse tumor xenograft model in vivo. PHLPP2, a target of miR-141 and miR-424, was downregulated in colon cancer. PHLPP2 upregulation and miR-141 and miR-424 downregulation suppressed the colon cancer cell proliferation, migration, invasion, and epithelial-mesenchymal transition, and promote cell apoptosis, which also resulted in suppression of tumor metastasis and formation. Furthermore, LINC00402, LINC00461, and SFTA1P were identified as the targets of miR-141 and miR-424 and acted as competitive endogenous RNAs (ceRNAs) of PHLPP2. The upregulation of LINC00402, LINC00461, and SFTA1P was verified to enhance the suppressive effects of PHLPP2 in the pathogenesis of colon cancer. Conjointly, our results demonstrated the suppressive effects of PHLPP2 in colon cancer and proved that LINC00402, LINC00461, and SFTA1P acted as ceRNAs of PHLPP2 by competitive binding to miR-141 and miR-424.

SRF Potentiates Colon Cancer Metastasis and Progression in a microRNA-214/PTK6-Dependent Manner.

ObjectiveSerum response factor (SRF), a sequence-specific transcription factor, is closely related to metastasis of gastric cancer, a digestive tract cancer. Herein, we probed the effect of SRF on metastasis and progression of colon cancer (CC), another digestive tract disorder, and the detailed mechanism.MethodsMicroarray analysis was conducted on tumor and adjacent tissues to filter differentially expressed miRNA, followed by RT-qPCR validation in CC cell lines. The transcription factor and the target gene of microRNA-214 (miR-214) were predicted, and their binding relationships were tested by luciferase reporter assays and ChIP assays. Subsequently, SRF and protein tyrosine kinase 6 (PTK6) expression in CC patients and cells was evaluated by RT-qPCR, while JAK2 and STAT3 expression in cells by Western blot analysis. To further explore functions of miR-214, PTK6 and SRF on CC, CC cells were delivered with si-PTK6, miR-214 mimic and/or SRF overexpression.ResultsmiR-214 expressed poorly in CC tissues and cell lines, which related to advanced TNM staging and survival. miR-214 mimic inhibited proliferation, migration, invasion, xenograft tumor growth and metastasis of CC cells. SRF, overexpressed in CC samples and cells, suppressed the transcription of miR-214. Meanwhile, SRF upregulation counteracted the inhibitory role of miR-214 mimic in CC cell growth. miR-214 negatively regulated PTK6 expression to impair the JAK2/STAT3 pathway activation, thereby halting CC cell proliferation, migration, invasion, xenograft tumor growth and metastasis.ConclusionAltogether, miR-214 may perform as a tumor suppressor in CC, and the SRF/miR-214/PTK6/JAK2/STAT3 axis could be applied as a biomarker and potential therapeutic target.

RETRACTED: Methyltransferase-like 1 (METTL1) served as a tumor suppressor in colon cancer by activating 7-methyguanosine (m7G) regulated let-7e miRNA/HMGA2 axis

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor-in-Chief. Concern was raised by a reader that the pictures of different cell lines in Fig. 3A and Fig. 4D were from the same cell line, suggesting repeated use of the same picture. The editor contacted the corresponding author for explanation, but there was no reply. Apologies are offered to readers of the journal that this was not detected during the submission process.

Dact2 is involved in the regulation of epithelial-mesenchymal transition

Dishevelled-associated antagonist of beta-catenin 2 (Dact2) is involved in the regulation of intracellular signaling pathways during development. It negatively regulates the Nodal signaling pathway, possibly by promoting lysosomal degradation of Nodal receptors such as TGFBR1, and plays an inhibitory role during the re-epithelialization of skin wounds by attenuating transforming growth factor-β signaling. Dact2 is known to act as a functional tumor suppressor in colon cancer; reduced Dact2 can promote liver cancer progression and suppress gastric cancer proliferation, invasion, and metastasis by inhibiting Wnt signaling. Zebrafish is used as a model of cancer biology because it shows similar tumorigenesis and morphogenesis as in humans and gene manipulation in this organism is possible. This study was performed to explore phenotypic changes in Dact2 knockout zebrafish and investigate the function of Dact2. A 10-base pair deletion Dact2 knockout zebrafish was prepared using the CRISPR-Cas9 genome editing system. Dact2 knockout enhanced the expression of the MMP2 and MMP9 genes, which are related to tumor invasion and migration, and the Snail, VEGF, and ZEB genes, which are related to epithelial-mesenchymal transition (EMT). The absence of Dact2 also resulted in hyperplasia of the gastrointestinal epithelium, fibrosis in the pancreas and liver, increased proliferation of the pancreatic and hepatic bile ducts, and invasive proliferation into the pancreas. A wound healing assay confirmed that the absence of Dact2 enhanced EMT, thus accelerating wound healing. This study suggests that a loss of function of Dact2 impacts EMT-related gene regulation and tumor generation in a zebrafish knockout model, which is a useful model for exploring the mechanisms of these processes.

Generation of a novel HBeAg transgenic mice using CRISPR/Cas9 technique

To generate a new strain of HBeAg transgenic mice using CRISPR/Cas9 technique. Hepatitis B virus (HBV) HBeAg gene was cloned and inserted in the pliver-HBeAg expression frame at the site of Rosa26 gene using CRISPR/Cas9 and homologous recombination techniques to construct the pliver-HBeAg expression vector containing HBeAg gene. The linear DNA fragment containing HBeAg gene was obtained by enzyme digestion. Cas9 mRNA, gRNA and the donor vector were microinjected into fertilized eggs of C57BL/6J mice, which were then transplanted into the uterus of C57BL/6J female surrogate mice to obtain F0 generation mice. The F0 generation mice were identified by long fragment PCR to obtain F0 transgenic mice with HBeAg gene. The positive F0 generation mice were bred with wild-type C57BL/6J mice to produce the F1 mice, which were identified by PCR and sequencing. The positive F1 transgenic mice carrying HBeAg gene were backcrossed until the homozygous offspring transgenic mice were obtained. The genotypes of the offspring mice were identified. The expressions of HBeAg and HBeAb in the heterozygous and homozygous HBeAg transgenic mice were detected by automatic chemiluminescence immunoassay, immune colloidal gold technique and immunohistochemistry method. A total of 56 F0 mice were obtained, and 2 of them carried homologous recombined HBeAg gene. Six positive F1 mice were obtained, from which 22 homozygous and 29 heterozygous F2 generation HBeAg transgenic mice were obtained. High concentration of HBeAg protein was detected in the peripheral blood of all the positive HBeAg transgenic mice without HBeAb expression. HBeAg expression was detected in the hepatocytes of HBeAg transgenic mice. We obtained a new strain of HBeAg transgenic mice with stable expression of HBeAg in the hepatocytes and immune tolerance to HBeAg using CRISPR/Cas9 technique, which provide a new animal model for studying HBV.

MicroRNA‑192 acts as a tumor suppressor in colon cancer and simvastatin activates miR‑192 to inhibit cancer cell growth.

Colon cancer is one of the most common malignant tumors worldwide. Understanding the underlying molecular mechanisms is crucial for the development of therapeutic strategies for the treatment of patients with colon cancer. In the present study, a novel tumor suppressive microRNA, miR‑192, was demonstrated to be markedly downregulated in colon cancer cells compared with normal colon cells. By overexpressing miR‑192 in colon cancer HCT‑116 cells, the results of the present study revealed that miR‑192 inhibits cell proliferation, migration and invasion. Bioinformatics were used to determine the target gene of miR‑192 and Ras‑related protein Rab‑2A (RAB2A) was identified as a downstream target of miR‑192. Following the determination of the role of the miR‑192‑RAB2A pathway in colon cancer, small molecules that may regulate miR‑192 were screened and the results demonstrated that simvastatin is an activator of miR‑192. Furthermore, simvastatin upregulated miR‑192 and inhibited the expression of downstream targets of miR‑192, which subsequently led to suppressed proliferation, migration and invasion of colon cancer cells. In conclusion, the present study identified a novel colon cancer cell suppressor, as well as a small‑molecule activator of the tumor suppressor miR‑192, which may represent a therapeutic strategy for the treatment of patients with colon cancer.

MicroRNA-423-5p inhibits colon cancer growth by promoting caspase-dependent apoptosis.

Plasma microRNA (miR)-423-5p is a potential biomarker for the detection of colon cancer. However, the expression and biological role of miR-423-5p in colon tumorigenesis remains unclear. In the current study, reverse transcription-quantitative polymerase chain reaction was used to determine miR-423-5p expression in malignant colon tissues and plasma from patients with colon cancer. Cell viability, colony formation and apoptosis assays, as well as western blotting, were performed to investigate the biological role and regulatory mechanisms of miR-423-5p in colon cancer. The results demonstrated that miR-423-5p expression was downregulated in tumor tissues and plasma from patients with colon cancer, as well as in colon cancer cell lines. Furthermore, overexpression of miR-423-5p promoted colon cancer cell apoptosis and resulted in the inhibition of cell proliferation and colony formation. Mechanistically, miR-423-5p induced the expression of caspases 3, 8 and 9, as well as p53 in colon cancer. The effect of z-VAD treatment indicated that the miR-423-5p-mediated colon cancer cell apoptosis is caspase-dependent. These results suggest that miR-423-5p is a tumor suppressor in colon cancer and a potential diagnostic target to enable the early detection of colon cancer.