Signaling Pathway In Colorectal Cancer Research Articles

New Roles for Fusobacterium nucleatum in Cancer: Target the Bacteria, Host, or Both?

Fusobacterium nucleatum is an oral bacterium associated with colorectal cancer (CRC) proliferation, chemoresistance, inflammation, metastasis, and now DNA damage. While controlling F. nucleatum through antibiotics could reduce cancer severity, this article proposes additional strategies to block Fusobacterium-host interactions, as well as treatment of activated host immune and oncogenic signaling pathways in CRC.

Identification of key genes involved in JAK/STAT pathway in colorectal cancer

JAK/STAT pathway has been well confirmed in the development of colorectal cancer (CRC), however, the exact mechanism is unclear. Therefore, we aimed to identify key genes involved in JAK/STAT pathway in CRC, as well as the potential mechanism. RT² profiler PCR arrays were performed to identify key genes of the JAK/STAT pathway. GO, KEGG pathway and PPI analyses were performed to screen the main functions of differentially expressed genes (DEGs). Moreover, the expression of DEGs was detected by GEPIA based on TCGA database and verified by qPCR and/or Western blot. Subsequently, the association between the two DEGs (CXCL9 and IL6ST) and clinicopathological features were determined by immunohistochemistry, and survival analysis was also conducted. Finally, the effects of IL6ST overexpression on STAT3 activation and HT29 cell functions were analyzed. A total of 14 DEGs were identified. Among the DEGs, GHR, NR3C1, IL6ST and A2M were confirmed to be statistically decreased, while CXCL9 was significantly increased in the CRC tissues. Furthermore, CXCL9 was significantly associated with differentiation, lymph node metastasis, distant metastasis and invasion, while IL6ST was related with tumor size, differentiation, stage and invasion. Patients with high expression of IL6ST presented significantly lower lifetime, however, CXCL9 showed the opposite results without significance. Additionally, we found that overexpression of IL6ST statistically elevated p-STAT3 level, cell viability, adhesion rate and migration, and decreased apoptosis, but had no effects on cell cycle. Our results suggest that IL6ST is a critical key gene involved in JAK/STAT signaling pathway in CRC.

Pathological significance of abnormal recepteur d'origine nantais and programmed death ligand 1 expression in colorectal cancer.

BACKGROUNDProgrammed death ligand 1 (PD-L1) immunotherapy remains poorly efficacious in colorectal cancer (CRC). The recepteur d’origine nantais (RON) receptor tyrosine kinase plays an important role in regulating tumor immunity.AIMTo identify the patterns of RON and PD-L1 expression and explore their clinical significance in CRC.METHODSGene expression data from the Gene Expression Omnibus database (GEO; n = 290) and patients at the First Affiliated Hospital, Zhejiang University School of Medicine (FAHZUSM; n = 381) were analyzed to determine the prognostic value of RON and PD-L1 expression within the tumor microenvironment of CRC. HT29 cell line was treated with BMS-777607 to explore the relationship between RON activity and PD-L1 expression. Signaling pathways and protein expression perturbed by RON inhibition were evaluated by cellular immunofluorescence and Western blot.RESULTSIn the GEO patient cohort, cut-off values for RON and PD-L1 expression were determined to be 7.70 and 4.3, respectively. Stratification of patients based on these cutoffs demonstrated that high expression of RON and PD-L1 was associated with a poor prognosis. In the FAHZUSM cohort, rates of high expression of RON in tumor cells, high PD-L1 expression in tumor cells and tumor infiltrating monocytes, and both high RON and high PD-L1 expression in the tumor microenvironment were 121 (32%), 43 (11%), 91 (24%), and 51 (13.4%), respectively. High expression of RON was significantly correlated with high expression of PD-L1 in the tumor cell compartment (P < 0.001). High expression of RON and that of PD-L1 were independent prognostic factors for poorer overall survival. Concurrent high expression of both RON and PD-L1 in the tumor microenvironment was significantly associated with a poor prognosis. In vitro, BMS-777607 inhibited the phosphorylation of RON, inhibited PD-L1 expression, and attenuated activation of the ERK1/2 and AKT signaling pathways in CRC cells.CONCLUSIONRON, PD-L1, and their crosstalk are significant in predicting the prognostic value of CRC. Moreover, phosphorylation of RON upregulates PD-L1 expression, which provides a novel approach to immunotherapy in CRC.

LncRNA SNHG11 facilitates tumor metastasis by interacting with and stabilizing HIF-1\u03b1

Epigenetic alteration is one of the hallmarks of colorectal cancer (CRC). Many driver genes are regulated by DNA methylation in CRC. However, the role of DNA methylation regulating lncRNAs remain elusive. Here, we identify that SNHG11 (small nucleolar RNA host gene 11) is upregulated by promotor hypomethylation in CRC and is associated with poor prognosis in CRC patients. SNHG11 can promote CRC cell migration and metastasis under hypoxia. Interestingly, the DNA-binding motif of SNHG11 is similar to that of HIF-1α. In addition, SNHG11-associated genes are enriched with members of the HIF-1 signaling pathway in CRC. Mechanistically, SNHG11 binds to the pVHLrecognition sites on HIF-1α, thus blocking the interaction of pVHL with HIF-1α and preventing its ubiquitination and degradation. Moreover, SNHG11 upregulates the expression of HIF-1α target genes, i.e., AK4, ENO1, HK2, and Twist1. Notably, SNHG11 can bind to the HRE sites in the promoter of these genes and increase their transcription. In summary, these results identify a SNHG11/ HIF-1α axis that plays a pivotal role in tumor invasion and metastasis.

TAGLN and High-mobility Group AT-Hook 2 (HMGA2) Complex Regulates TGF-β-induced Colorectal Cancer Metastasis.

BackgroundColorectal cancer is one of the three most common cancers worldwide. Altered TGF-β signaling pathway in colorectal cancer is associated with metastasis and poor prognosis. It is also involved in epithelial-to-mesenchymal transition (EMT), which is essential in progression and metastasis. This study aims to investigate the role of transgelin (TAGLN) and high-mobility group AT-hook 2 (HMGA2) in the progression of colon cancer.MethodsHT29 and HCT116 cells were treated with TGF-β, and the effects of inhibition of TAGLN and overexpression of HMGA2 on TGF-β treated cell on cell migration and invasion, expression of EMT markers, including E-cadherin, vimentin and fibronectin were detected as well as MMP2 and MMP9, which are critical in cancer cell metastasis. The interaction of TAGLN and HMGA2 was also investigated by using co-immunoprecipitation. The function of TAGLN in tumor metastasis and growth was investigated in vivo.ResultsWe found that TGF-β could significantly promote the migration of HT29 and HCT116 cells, as well as TAGLN protein expression and nucleus translocation, while inhibition of TAGLN could effectively reverse the effects of TGF-β on HT29 and HCT116 cells, which was observed in terms of decreased cell migration and invasion. Knockdown of TAGLN could also rescue TGF-β-induced loss of E-cadherin, and decreased TGF-β-induced vimentin and fibronectin expression; the elevation of MMP9 and MMP2 was also reversed by inhibition of TAGLN. Further investigation confirmed the interaction of HMGA2 and TAGLN, as overexpression of HMGA2 restores the effects of TGF-β on HT29 cells, which were attenuated by TAGLN inhibition both in vitro and in vivo.ConclusionOverall, our study revealed that interaction between TAGLN and HMGA2 was involved in TGF-β-induced cell migration and promotion of colon cancer cells, suggesting that HMGA2 and TAGLN are potential molecular targets to prevent colon cancer progression.

Steroid 5α-Reductase Type I Induces Cell Viability and Migration via Nuclear Factor-κB/Vascular Endothelial Growth Factor Signaling Pathway in Colorectal Cancer.

Colorectal cancer (CRC) is a common malignant tumor of the digestive system. Steroid 5α-reductase type I (SRD5A1), as an important part of the steroid metabolism, converts testosterone to dihydrotestosterone and regulates sex hormone levels, which accommodates tumor occurrence or development. However, the underlying molecular mechanism of SRD5A1 in CRC remains unclear. We compared SRD5A1 expression in CRC tissues with normal controls by immunohistochemistry and found that elevated SRD5A1 in CRC was relevant for poor patient prognosis. Furthermore, inducible downregulation of SRD5A1 by small hairpin RNA reduced cell viability, promoted cell cycle arrest, and induced cell apoptosis and cellular senescence of CRC cells, as well as attenuated cell migration ability. In the following experiments, we used dutasteride (an inhibitor of SRD5A1/2) to explore its inhibitory effect on the biological processes of CRC cells, as mentioned earlier. Further mechanism study demonstrated that the repression of SRD5A1 abolished the expression of p65 and vascular endothelial growth factor, suggesting that SRD5A1 might regulate cell viability and migration through nuclear factor-κB/vascular endothelial growth factor signaling pathway. Collectively, these findings implicate SRD5A1 acting as a novel biomarker for CRC diagnosis and prognosis and provide compelling evidence for the future evaluation of dutasteride as a promising candidate for CRC treatment.

Gambogenic acid induces Noxa-mediated apoptosis in colorectal cancer through ROS-dependent activation of IRE1α/JNK

BackgroundGambogenic acid (GNA), an active component of Garcinia hanburyi Hook.f. (Clusiaceae) (common name gamboge), exerts anti-inflammatory and antitumor properties. However, the underlying mechanism of GNA in colorectal cancer (CRC) is still not well understood. PurposeThis study aimed to investigate the antitumor effects and mechanisms of GNA on CRC in vitro and in vivo. MethodsCell viability, colony formation and cell apoptosis assays were performed to determine the antitumor effects of GNA. qRT-PCR and Western blotting were performed to evaluate the expression of genes or proteins affected by GNA in vitro and in vivo. HCT116 colon cancer xenografts and the APCmin/+ mice model were used to confirm the antitumor effects of GNA on CRC in vivo. ResultsGNA induced Noxa-mediated apoptosis by inducing reactive oxygen species (ROS) generation and c-Jun N-terminal kinase (JNK) activation. Moreover, GNA triggered endoplasmic reticulum (ER) stress, which subsequently activated inositol-requiring enzyme-1α (IRE1α) leading to JNK phosphorylation. ROS scavenger attenuated GNA-induced IRE1α activation and JNK phosphorylation. Knockdown of IRE1α also prevented GNA-induced JNK phosphorylation. In vivo, GNA suppressed tumor growth and progression in HCT116 colon cancer xenografts and the APCmin/+ mices model. ConclusionThese findings revealed that GNA induced Noxa-mediated apoptosis by activating the ROS/IRE1α/JNK signaling pathway in CRC both in vitro and in vivo. GNA is therefore a promising antitumor agent for CRC treatment.

Abstract 2443: miR-146a methylation regulates proliferation and metastasis by targeted activation of VASN/TGF-beta signaling pathway in colorectal cancer

Abstract Tumor specific alterations in miRNA provide ideal biomarkers for early diagnosis of colorectal cancer(CRC). Methylation changes play an important role in the miRNA regulation mechanism involved in tumorigenesis. Therefore, it is important to find miRNA methylation markers related to tumor proliferation and metastasis, and to explore its key regulatory mechanisms. Previous integrated bioinformatics analysis suggested that reduced expression and hypermethation of miR-146a have detected in majority of CRC. However, its biological behavior in CRC remains unclear. This article aims to explore its epigenetic regulation and mechanism in the development of CRC. We collected peripheral blood and tissues from 60 patients with advanced primary CRC, analyzed their clinicopathological characteristics. The mRNA and methylation difference was detected by qPCR and MSP respectively, and the significance in the diagnosis of CRC was analyzed. The research was further confirmed in SW480, SW620, HCT116 and HT29 CRC cell lines, as well as CRC animal models treated with demethylated drugs–5-aza-miR2-oxyeytidineine(5-AZA) and various gene transfection, in order to explore the key downstream regulatory network of miR-146a methylation changes and the effect of methylation inhibitors in the development of CRC. We found that the percentage of down-regulated and methylation of miR-146a in both tissues and plasmas of CRC was significantly higher than that of normal samples, and the expression of miR-146a could be recovered after demethylation treatment in cancer, which was associated with clinical stage. miR-146a methylation was significantly correlated with grading, but not gender, tumor location, histological type or TNM, it may be used as a predictor of poor prognosis. Diagnostic evaluation of miR-146a methylation in tissue and plasma was evaluated using ROC curve, area under regional curve, which indicated that miR-146a methylation could be used as a biomarker for the diagnosis of CRC. Fluorescein report system showed that miR-146a targeted VASN protein, and while miR-146a was overexpressed after transfection into CRC cells, the expression levels of VASN, TGF-β, VEGF-C, MMP9, and Vimentin were significantly reduced, while the expression of TIMP1 and Ecadherin were up-regulated. Additionally, the miR-146a mRNA in CRC tissues was also negatively correlated with the expression of VASN. VASN Silencing down-regulated TGF-β expression, accompanied by a decrease of MMP9. At the same time, after 5-aza demethylation or siVASN, proliferation activity of CRC cells decreased, accompanied by varying degrees of decline in membrane penetrating and migration ability, suggesting that miR-146a may regulate the proliferation and metastasis by regulating VASN/TGF-β relatived pathway. In vivo animal models, it was further confirmed that overexpressed miR-146a was consistent with the effect of 5-aza intervention or siVASN, which could significantly inhibit the occurrence of liver metastasis of CRC. Demethylated drugs treatment or VASN knockdown also significantly inhibited tumor growth in nude mice with CRC. miR-146a was a potential epigenetic silencing tumor suppressor in CRC, and the methylation of miR-146a may play an important role in the diagnosis and prediction of tumor progression in CRC as a new tumor marker. Citation Format: Weiwei Tang, Dan Zhou, Hanxiang An, Jiapeng Kang, Mingquan Cai, Ru Zeng, Jing Song, Bin Hu, Jiabian Lian, Qin Lin, Lilin Chen, Feng Ye. miR-146a methylation regulates proliferation and metastasis by targeted activation of VASN/TGF-beta signaling pathway in colorectal cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2443.

Asiaticoside suppresses cell proliferation by inhibiting the NF‑κB signaling pathway in colorectal cancer.

Colorectal cancer (CRC) is one of the leading causes of cancer-associated mortality. Asiaticoside (AC) exhibits antitumor effects; however, to the best of our knowledge, the biological function of AC in CRC cells remains unclear. Therefore, the aim of the present study was to investigate the effect of AC on CRC cells. In the present study, CCK-8 and colony formation assays were performed to assess the effects of AV on human CRC cell lines (HCT116, SW480 and LoVo). Mitochondrial membrane potential was examined by JC-1 staining. Cell apoptosis and cell cycle were monitored by flow cytometry, and the expression of genes was evaluated using RT-qPCR and western blot analysis. Furthermore, the biological effect of AC in vivo was detected using a xenograft mouse model. The findings revealed that 2 µM AC suppressed the proliferation of CRC cells in a time- and dose-dependent manner, but had no adverse effects on normal human intestinal FHC cells at a range of concentrations. AC decreased the mitochondrial membrane potential and increased the apoptosis of CRC cells in a dose-dependent manner. Furthermore, AC induced cell cycle arrest at the G0/G1 phase. AC attenuated IκBα phosphorylation in a dose-dependent manner, thereby preventing P65 from entering the nucleus, and resulting in inhibition of the NF-κB signaling pathway. In addition, AC significantly reduced the expression of CDK4 and Cyclin D1 in a dose-dependent manner, significantly upregulated the activation of caspase-9 and caspase-3, and decreased the Bcl-2/Bax mRNA ratio. Furthermore, treatment with the NF-κB signaling pathway inhibitor JSH-23 significantly increased the cytotoxicity of AC in CRC cells. Findings of the xenograft mice model experiments revealed that AC significantly inhibited colorectal tumor growth in a dose-dependent manner. Overall, AC suppressed activation of the NF-κB signaling pathway by downregulating IκBα phosphorylation. This resulted in inhibition of CRC cell viability and an increase of cell apoptosis, which may form the basis of AC use in the treatment of patients with CRC.

Placenta-specific protein 1 enhances liver metastatic potential and is associated with the PI3K/AKT/NF-κB signaling pathway in colorectal cancer.

To better explore the underlying mechanism of liver metastatic formation by placenta-specific protein 1 (PLAC1) in human colorectal cancer, we investigated the proliferation, invasion and angiogenic capabilities of human colorectal cancer cells with different liver metastatic potentials as well as the mechanism of action of PLAC1 in the metastatic process. The expression of PLAC1 was detected by reverse transcriptase PCR, western blot, and real-time PCR. The effect of PLAC1 on metastatic potential was determined by proliferation, invasion, and angiogenesis assays, including an in-vitro coculture system consisting of cancer cells and vascular endothelial cells that were used to detect the relationship between cancer cells and angiogenesis. In addition, we also determined PLAC1 downstream targets that preferentially contribute to the metastatic process. PLAC1 was expressed in HT-29, WiDr, and CaCo-2 colorectal cancer cells but not in Colo320 colorectal cancer cells. PLAC1 not only enhanced significantly the proliferation of CoLo320 and human umbilical vein endothelial cells (HUVECs) but also promoted the invasion of CoLo320 cells. The angiogenesis of HUVECs was enhanced by PLAC1 in a dose-dependent manner. In cocultured systems, angiogenesis was significantly increased by coculture with HT-29 cells. In addition, PLAC1 could promote angiogenesis in coculture with HT-29 cells. Furthermore, PLAC1-enhanced metastatic potential of colorectal cancer cells was dependent on the activation of the PI3K/Akt/NF-κB pathway. The activation of PI3K/Akt/NF-κB signaling by PLAC1 may be critical for metastasis of colorectal cancer cells. According to our results, we suggest that modification of PLAC1 function might be a promising new therapeutic approach to inhibit the aggressive spread of colorectal cancer.

Cancer Stem Cells and Signaling Pathways in Colorectal Cancer

Colorectal cancer (CRC) is the third most common cancer in males, the second in females and is the second leading cause of cancer related death worldwide. Despite recent advances in chemotherapy, and targeted therapy for CRC, the prognosis for patients with advanced cancer has remained poor, due to drug resistance, metastasis and recurrence. A small fraction of cells possess tumor propagation abilities. These are termed “cancer stemcells (CSCs). A subset of colorectal cancer stem cells, may hold a key to controlling cancer. The cancer stem cell (CSC) model suggests that tumors are hierarchically organized, only CSCs possess cancer-promotingpotential. The killing of CSCs is thought to be a critical component of effective antitumor therapies. A number of signaling pathways, most notably the Wingless related (Wnt), transforming growth factor-beta (TGF-β), Notch and Hedgehog signaling and other mechanisms have been found to be associated with CSCs in CRC. They play important roles in maintaining the growth and functional integrity of CSC. Many new molecules are now being studied to block theses pathways. Some of the molecules block the self-renewal and induction of apoptosis in CSCs. The design of CSC-targeted interventions is a rational target, and reduce local recurrenceand metastasis. This review aims to summarize the issue on CSCs and signaling pathway relevant for CRC, which may lead to more effective therapeutic strategies for CRC.

Nitric Oxide (NO) and NO Synthases (NOS)-Based Targeted Therapy for Colon Cancer.

Colorectal cancer (CRC) is one of the most lethal malignancies worldwide and CRC therapy remains unsatisfactory. In recent decades, nitric oxide (NO)—a free-radical gas—plus its endogenous producer NO synthases (NOS), have attracted considerable attention. NO exerts dual effects (pro- and anti-tumor) in cancers. Endogenous levels of NO promote colon neoplasms, whereas exogenously sustained doses lead to cytotoxic functions. Importantly, NO has been implicated as an essential mediator in many signaling pathways in CRC, such as the Wnt/β-catenin and extracellular-signal-regulated kinase (ERK) pathways, which are closely associated with cancer initiation, metastasis, inflammation, and chemo-/radio-resistance. Therefore, NO/NOS have been proposed as promising targets in the regulation of CRC carcinogenesis. Clinically relevant NO-donating agents have been developed for CRC therapy to deliver a high level of NO to tumor sites. Notably, inducible NOS (iNOS) is ubiquitously over-expressed in inflammatory-associated colon cancer. The development of iNOS inhibitors contributes to targeted therapies for CRC with clinical benefits. In this review, we summarize the multifaceted mechanisms of NO-mediated networks in several hallmarks of CRC. We review the clinical manifestation and limitations of NO donors and NOS inhibitors in clinical trials. We also discuss the possible directions of NO/NOS therapies in the immediate future.

Characterization of lncRNA-Perturbed TLR-Signaling Network Identifies Novel lncRNA Prognostic Biomarkers in Colorectal Cancer.

Increasing evidence has suggested that long non-coding RNAs (lncRNAs) are critical regulators in the Toll-like receptors (TLR)-signaling network to modulate colorectal cancer (CRC) development and progression. However, the mechanism and clinical significance for lncRNAs regulating TLR signaling pathways in CRC remained largely unknown. In this study, we performed an integrative network analysis of transcriptomics by focusing on a lncRNA-perturbed TLR-signaling network, identifying 280 lncRNAs and 122 mRNAs. We found a profound phenomenon that abnormal expression of some lncRNAs can perturb the TLR-signaling network to contribute to CRC development and progression. Furthermore, we identified a novel TLR-related prognostic gene signature (TLRLncSig) composed of three lncRNAs (MCHR2, AC011472.4, and AC063944.1), and one mRNA (CDKN2B). Utilizing TLRLncSig could classify CRC patients of training set into two groups with significantly different overall survival. The prognostic value of the TLRLncSig was further validated in the other two independent CRC datasets with different platforms. Results of multivariate and stratification analysis indicated that the TLRLncSig is an independent prognostic factor, and our study underscores the clinical significance of TLR-related lncRNAs in CRC development and progression.

Fibronectin promotes tumor cells growth and drugs resistance through a CDC42-YAP-dependent signaling pathway in colorectal cancer.

Fibronectin (FN) is a high-molecular-weight glycoprotein of the extracellular matrix (ECM) that binds to membrane-spanning receptor proteins or other elements in ECM. The expression of FN could be involved in the cancer cells proliferation or migration, and the molecular mechanisms responsible for FN induced protumor signals begin to be elucidated. Here, we report that the elevated expression of FN was observed in those chemoresistant tumor tissues from patients with colorectal cancer. Consistently, FN culture significantly strengthened the proliferation of colorectal cancer cells, induced the colorectal tumor sustained growth and drug resistance in vitro and in vivo. In mechanism, FN could bind to integrin αvβ1, resulting the downstream cell division cycle 42/yes-associated protein 1 (CDC42/YAP-1) signaling pathway activation. The activation of CDC42/YAP-1 signal induces the upregulation of transcription factor SOX2, causing the sustained growth and drugs resistance in colorectal cancer. Blockade of integrin αvβ1 significantly suppressed the colorectal cancer growth and drugs resistance development in vitro and in vivo, which provides a new target for clinical colorectal cancer treatment.

Anlotinib Suppresses Colorectal Cancer Proliferation and Angiogenesis via Inhibition of AKT/ERK Signaling Cascade.

BackgroundAnlotinib is a highly potent multi-target tyrosine kinase inhibitor, with very good anti-tumor activity against a variety of solid tumors. However, its effect on colorectal cancer (CRC) is not yet clearly understood. The objective of this study was to investigate the anti-tumor effect and underlying mechanism of anlotinib in the pathogenesis of CRC.Materials and MethodsEffects of anlotinib on CT26 cells proliferation and microvessel formation in endothelial cells were determined by MTT assay and tube formation assay. Cell migration and invasion were analyzed by using the wound healing assay and transwell assay. Cell cycle and apoptosis were detected by flow cytometry. A CRC xenograft mouse model was used for conducting in-vivo studies to verify the effect of anlotinib. The expression of Ki-67 and CD31 in the tumor tissue was detected by immunohistochemistry and protein expression was measured by Western blot.ResultsIn-vitro studies revealed that anlotinib inhibited the proliferation, migration, and invasion of CT26 cells and the tube formation of HUVECs in a dose-dependent manner. Anlotinib also significantly induced cell apoptosis and G2/M arrest. It effectively inhibited tumor growth and prolonged survival time in the CRC xenograft mouse model. Immunohistochemical analysis of the tumor tissue revealed that anlotinib downregulated CD31 and Ki-67 which are the biomarkers of microvessel density and proliferation. Furthermore, anlotinib was able to inhibit the activation of VEGFR-2/AKT and FGFR, PDGFRβ and their downstream signaling ERK.ConclusionThe findings of the present study suggested that anlotinib suppressed cell proliferation and angiogenesis via inhibition of AKT/ERK signaling pathway in colorectal cancer and could be a novel therapeutic strategy for treatment of CRC.

LACTB Regulates PIK3R3 to Promote Autophagy and Inhibit EMT and Proliferation Through the PI3K/AKT/mTOR Signaling Pathway in Colorectal Cancer.

BackgroundColorectal cancer (CRC) is one of the most common aggressive malignancies. LACTB functions as a tumor suppressor, and previous findings have demonstrated that LACTB can inhibit epithelial-to-mesenchymal transition (EMT) and proliferation of breast cancer and CRC cells. However, few studies have investigated the roles of LACTB in autophagy and proliferation in CRC. The current study aimed to identify the roles of LACTB in EMT and proliferation associated with autophagy in CRC and to elucidate the probable molecular mechanisms through which LACTB are involved in these processes.Materials and MethodsTranswell invasion, MTT, transmission electron microscopy, RNA-seq, immunoprecipitation, immunohistochemistry and Western blotting assays were performed to evaluate the migratory, invasive, proliferative and autophagic abilities of CRC cells, and the levels of active molecules involved in PI3K/AKT signaling were examined through Western blotting analysis. In addition, the in vivo function of LACTB was assessed using a tumor xenograft model.ResultsWeaker LACTB expression was found in CRC tissue samples than in nonmalignant tissue samples, and LACTB inhibited cell invasion, migration, and proliferation by promoting autophagy in vitro. Furthermore, the regulatory effects of LACTB on autophagy and EMT were partially attributed to the PI3K/AKT signaling pathway. The in vivo results also showed that LACTB modulated CRC tumorigenesis.ConclusionLACTB can regulate the activity of PIK3R3 to influence the level of PI3K, and it also promotes autophagy and inhibits EMT and proliferation in part through the PI3K/AKT/mTOR signaling pathway.

Pharmacogenomics of 5-fluorouracil in colorectal cancer: review and update.

Colorectal cancer (CRC) is a disease with high morbidity and mortality rates. 5-fluorouracil (5-FU) is the first-line recommended drug for chemotherapy in patients with CRC, and it has a good effect on a variety of other solid tumors as well. Unfortunately, however, due to the emergence of drug resistance the effectiveness of treatment may be greatly reduced. In the past decade, major progress has been made in the field of 5-FU drug resistance in terms of molecular mechanisms, pre-clinical (animal) models and clinical trials. In this article we systematically review and update current knowledge on 5-FU pharmacogenomics related to drug uptake and activation, the expression and activity of target enzymes (DPD, TS and MTHFR) and key signaling pathways in CRC. Furthermore, a summary of drug combination strategies aimed at targeting specific genes and/or pathways to reverse 5-FU resistance is provided. Based on this, we suggest that causal relationships between genes, pathways and drug sensitivity should be systematically considered from a multidimensional perspective. In the design of research methods, emerging technologies such as CRISPR-Cas, TALENS and patient-derived xenograft models should be applied as far as possible to improve the accuracy of clinically relevant results.

LncRNA KCNQ1OT1 knockdown inhibits colorectal cancer cell proliferation, migration and invasiveness via the PI3K/AKT pathway.

Colorectal cancer (CRC) is one of the most common primary malignancies worldwide. Numerous studies have demonstrated that long non-coding RNAs (lncRNAs) are considered as crucial regulators of tumor progression. In particular, upregulation of the lncRNA KCNQ1OT1 was reported in various types of malignancy as a promoter of tumor progression. However, the role and underlying mechanism of KCNQ1OT1 in CRC remain unclear. Thus, the present study aimed to investigate the role of KCNQ1OT1 in colorectal cancer through GEPIA, reverse transcription-quantitative PCR (RT-qPCR) and western blot analyses, and cell assays. GEPIA analysis demonstrated that high expression levels of KCNQ1OT1 in CRC tissues predicted a poor prognosis for patients with CRC. KCNQ1OT1 was overexpressed in CRC tissues and cell lines via RT-qPCR analysis. Furthermore, the results from the cell viability assay, colony formation assay, wound healing assay, invasion assay and flow cytometric analysis demonstrated that KCNQ1OT1 knockdown significantly inhibited CRC cell proliferation, migration and invasiveness, and promoted CRC cell apoptosis, leading to cell cycle arrest. Western blot analysis demonstrated that KCNQ1OT1 knockdown inhibited the PI3K/AKT signaling pathway. These results suggest that KCNQ1OT1 may act as an oncogene through the PI3K/AKT signaling pathway in CRC.

TUSC3 induces drug resistance and cellular stemness via Hedgehog signaling pathway in colorectal cancer.

Tumor suppressor candidate 3 (TUSC3) is a coding gene responsible for N-glycosylation of many critical proteins. TUSC3 gene plays an oncogenic role in colorectal cancer (CRC), however, the role of TUSC3 in drug resistance of CRC is still unclear. The aim of this study is to investigate the biological function and molecular mechanism of TUSC3 in CRC drug resistance. The expression of TUSC3 in CRC is positively correlated to tumor stage in 90 paired clinical samples, and negatively associated with overall survival and disease-free survival of CRC patients. In vitro, TUSC3 promotes the formation of stemness and induces the drug resistance to 5-fluorouracil and cis-dichlorodiammineplatinum(II) in CRC cells. The tissue microarray assay and bioinformatic analysis indicate that TUSC3 may promote the expression of CD133 and ABCC1 via Hedgehog signaling pathway. Treatment of Hedgehog signaling pathway agonist or inhibitor in TUSC3-silenced or TUSC3-overexpressed cells reverse the effects of TUSC3 in cellular stemness phenotype and drug resistance. Meanwhile, coimmunoprecipitation and immunofluorescence assays indicate a tight relationship between TUSC3 and SMO protein. Our data suggest that TUSC3 promotes the formation of cellular stemness and induces drug resistance via Hedgehog signaling pathway in CRC.

Silencing DVL3 defeats MTX resistance and attenuates stemness via Notch Signaling Pathway in colorectal cancer

Chemoresistance and recurrence of colorectal cancer are mainly caused by the existence of cancer stem-like cells. Dishevelled-3 (DVL3) is a common member of both Wnt/β-catenin pathway and the Notch signaling pathway, which were involved in cancer progression, chemoresistance and even maintenance of stem cell-like properties. However, the underlying biological function of DVL3 still remains unclear. In this study, we proposed DVL3 was simultaneously involved in Methotrexate (MTX) resistance and Colorectal cancer (CRC) stemness by bioinformatic analysis. We also demonstrated DVL3 knockdown sensitized CRC cells to MTX and inhibited their stem cell-like properties by functional experiments. As for the mechanism, DVL3 silencing attenuated the activated Notch signaling by down-regulating Notch intracellular domain (NICD) as well as its downstream targets. Additionally, we demonstrated that CRC cancer tissues had greater DVL3 expression than adjacent non-cancer tissues and patients’ overall survival was closely associated with DVL3 according to the data in our clinical center. Accordingly, our data suggest that DVL3 is a key regulator in CRC stemness and chemoresistance and targeting DVL3 could be a potential strategy for CRC therapy.