Promotes Colon Cancer Progression Research Articles

LncRNA-MIR17HG mediated upregulation of miR-17 and miR-18a promotes colon cancer progression via activating Wnt/β-catenin signaling.

BackgroundLong non-coding RNA MIR17HG (miR-17-92 cluster host gene lncRNA) is synthesized from miR-17-92 cluster host gene due to pre-miRNA processing, and is referred as miRNA-host gene lncRNA (lnc-miRHG). Until now, the biologic function of most lnc-miRHGs in tumor progression is not well understood. This study aimed to investigate the expression and clinical significance of MIR17HG in colon cancer.MethodsQuantitative real-time PCR analysis was used to evaluate MIR17HG expression in colon cancer tissues and paired adjacent normal mucosa. The levels of miR-17-92 cluster and important components of Wnt/β-catenin signaling pathway were also explored. Cell biology assays were used to investigate biologic consequences of MIR17HG in regulating cell proliferation, colony formation and invasion, as well as the roles in regulating epithelial-mesenchymal transition (EMT). Moreover, a colon tumor xenograft model was established to explore the in vivo effect of MIR17HG on cell proliferation.ResultsExpression of MIR17HG was found to be elevated in colon cancer (P<0.001). Upregulation of MIR17HG was significantly correlated with lymph node metastasis (P=0.005) and TNM stage (P<0.001), and also an independent prognostic indicator of overall survival and disease-free survival in colon cancer patients. Suppression of MIR17HG inhibited colon cancer cell viability, invasion, and EMT process, and significantly reduced the ability of the cells to form tumors in vivo. Moreover, miR-17 and miR-18a, two key components of miR-17-92 cluster, were suppressed after knockdown of MIR17HG. Furthermore, the Wnt/β-catenin signaling, activated by miR-17 and miR-18a, was required for the oncogenic role of MIR17HG in colon cancer.ConclusionsMIR17HG mediated upregulation of miR-17 and miR-18a promotes the progression of colon cancer via activating Wnt/β-catenin signaling.

LncRNA-MIR17HG mediated upregulation of miR-17 and miR-18a promotes colon cancer progression via activating Wnt/β-catenin signaling

Background: Long non-coding RNA MIR17HG (miR-17-92 cluster host gene lncRNA) is synthesized from miR-17-92 cluster host gene due to pre-miRNA processing, and is referred as miRNA-host gene lncRNA (lnc-miRHG). Until now, the biologic function of most lnc-miRHGs in tumor progression is not well understood. This study aimed to investigate the expression and clinical significance of MIR17HG in colon cancer. Methods: Quantitative real-time PCR analysis was used to evaluate MIR17HG expression in colon cancer tissues and paired adjacent normal mucosa. The levels of miR-17-92 cluster and important components of Wnt/β-catenin signaling pathway were also explored. Cell biology assays were used to investigate biologic consequences of MIR17HG in regulating cell proliferation, colony formation and invasion, as well as the roles in regulating epithelial-mesenchymal transition (EMT). Moreover, a colon tumor xenograft model was established to explore the in vivo effect of MIR17HG on cell proliferation. Results: Expression of MIR17HG was found to be elevated in colon cancer (P in vivo . Moreover, miR-17 and miR-18a, two key components of miR-17-92 cluster, were suppressed after knockdown of MIR17HG. Furthermore, the Wnt/β-catenin signaling, activated by miR-17 and miR-18a, was required for the oncogenic role of MIR17HG in colon cancer. Conclusions: MIR17HG mediated upregulation of miR-17 and miR-18a promotes the progression of colon cancer via activating Wnt/β-catenin signaling.

Cleavage and polyadenylation specific factor 4 promotes colon cancer progression by transcriptionally activating hTERT

CPSF4 was identified as a crucial tumorigenic factor in lung cancer development. However, its precise function and the underlying molecular mechanisms in colon cancer progression remain completely unknown. Here, we demonstrate CPSF4 was highly expressed in human colon cancer cells and tissues. Its knockdown inhibited colorectal cancer progression in vitro, including cell proliferation, migration, invasion and stemness maintenance. In contrast, the ectopic overexpression of CPSF4 had the opposite effects in vitro and in vivo. Further mechanistic studies demonstrated that CPSF4 facilitated colorectal tumorigenesis and development partially through transcriptionally regulating hTERT expression by cooperating with NF-kB1 and co-anchoring at hTERT promoter −321 to −234 fragment. In addition, clinical samples analysis indicated that CPSF4 expression was positively correlated with hTERT, and the simultaneously high expression of CPSF4 and hTERT predicted poor patient outcome. Overall, our findings established CPSF4 as a pro-tumorigenic factor in colorectal cancer progression, and suggested that targeting CPSF4-hTERT axis may represent a promising therapeutic strategy in colon cancer treatment.

NEAT1 promotes colon cancer progression through sponging miR-495-3p and activating CDK6 in vitro and in vivo.

Recently, increasing evidence has indicated lncRNAs are powerful regulators in the progression of multiple tumors. Dysregulation of lncRNA NEAT1 has been recognized in many cancer types. Meanwhile, the studies on NEAT1 function have suggested that NEAT1 can serve as a crucial oncogene. Nevertheless, the investigation of NEAT1 in colon cancer is still few. In our study, the function of NEAT1 was studied in colon cancer. As we observed, NEAT1 level was obviously elevated in colon cancer cells. Then, HCT-116 and SW620 cells were stably infected with shRNA-NEAT1 for 48 hr. As exhibited, silence of NEAT1 could greatly repress colon cancer cell progression. Apoptosis of colon cancer cells was triggered and the cell cycle progression was remarkably inhibited by downregulation of NEAT1. Interestingly, as exhibited, miR-495-3p was obviously decreased in colon cancer cells and it significantly suppressed colon cancer progression. Subsequently, miR-495-3p was predicted as a target of NEAT1. CDK6 was speculated as the target of miR-495-3p and miR-495-3p modulated its expression negatively. Finally, it was indicated that NEAT1 promoted colon cancer development through modulating miR-495-3p and CDK6 in vivo. Taken these together, we reported that NEAT1 could sponge miR-495-3p to contribute to colon cancer progression through activating CDK6.

Increased expression of GEF-H1 promotes colon cancer progression by RhoA signaling

Colorectal cancer (CRC) is the third most common malignancy and a leading cause of cancer-related death worldwide. GEF-H1 is considered a RhoA-specific guanine nucleotide exchange factor. GEF-H1 upregulation may contribute to cancer cell migration and invasion and tumor progression. However, the expression and role of GEF-H1 in CRC have not yet been elucidated. This study attempted to elucidate how GEF-H1 drives tumor formation, motility, invasion and metastasis in colon cancer (CC). The expression of GEF-H1 in CC tissue microarrays (TMAs) was analyzed by immunohistochemistry (IHC). GEF-H1 was upregulated in CC tissues compared with adjacent non-tumoral tissues. In addition, we found that high GEF-H1 expression correlated with shorter overall survival and distant metastasis. Migration and invasion assays showed that GEF-H1 upregulation increased CC cell motility, invasion and metastasis. In contrast, functional knockdown of GEF-H1 by RNAi rescued the effects caused by GEF-H1 overexpression in CC cells. Overexpression of GEF-H1 re-organized the actin cytoskeleton, with increased punctate paxillin staining and F-actin stress fibers. Furthermore, western blotting showed that RhoA activation triggered by GEF-H1 overexpression caused phosphorylation of its downstream target, MLC2, in CC cells. In summary, the present study revealed that GEF-H1 is upregulated in CC tissues and plays a key role in CC metastasis through the GEF-H1-RhoA-MLC2 signaling pathway.

Increased nicotinamide adenine dinucleotide pool promotes colon cancer progression by suppressing reactive oxygen species level.

Nicotinamide adenine dinucleotide (NAD) exists in an oxidized form (NAD+) and a reduced form (NADH). NAD + plays crucial roles in cancer metabolism, including in cellular signaling, energy production and redox regulation. However, it remains unclear whether NAD(H) pool size (NAD + and NADH) could be used as biomarker for colon cancer progression. Here, we showed that the NAD(H) pool size and NAD +/NADH ratio both increased during colorectal cancer (CRC) progression due to activation of the NAD + salvage pathway mediated by nicotinamide phosphoribosyltransferase (NAMPT). The NAMPT expression was upregulated in adenoma and adenocarcinoma tissues from CRC patients. The NADH fluorescence intensity measured by two‐photon excitation fluorescence (TPEF) microscopy was consistently increased in CRC cell lines, azoxymethane/dextran sodium sulfate (AOM/DSS)‐induced CRC tissues and tumor tissues from CRC patients. The increases in the NAD(H) pool inhibited the accumulation of excessive reactive oxygen species (ROS) levels and FK866, a specific inhibitor of NAMPT, treatment decreased the CRC nodule size by increasing ROS levels in AOM/DSS mice. Collectively, our results suggest that NAMPT‐mediated upregulation of the NAD(H) pool protects cancer cells against detrimental oxidative stress and that detecting NADH fluorescence by TPEF microscopy could be a potential method for monitoring CRC progression.

Inhibition of hsa_circ_0001313 (circCCDC66) induction enhances the radio-sensitivity of colon cancer cells via tumor suppressor miR-338-3p: Effects of cicr_0001313 on colon cancer radio-sensitivity

Circular RNA_0001313 (circ_0001313), also known as circCCDC66, is a novel circRNA that recently found to be upregulated in colon cancer tissues and promote colon cancer progression. However, the role of circ_0001313 in regulating radio-sensitivity of colon cancer and its molecular mechanism remain undetermined. Here we found circ_0001313 was significantly upregulated and miR-338-3p was downregulated in radio-resistant colon cancer tissues compared to radio-sensitive tissues. Radiation treatment in colon cells triggered a remarkable upregulation of circ_0001313 and a downregulation of miR-338-3p. Knockdown of circ_0001313 reduced cell viability, colony formation rate and increased caspase-3 activity in colon cancer cells under irradiation. Moreover, circ_0001313 act as a sponge for miR-338-3p in colon cancer cells. Furthermore, miR-338-3p could reverse the effects of circ_0001313 knockdown on cell viability, colony formation, and caspase-3 activity. These findings revealed that knockdown of circ_0001313 could induce radio-sensitivity of colon cancer cells by negatively regulating miR-338-3p.

Surgical trauma-induced CCL18 promotes recruitment of regulatory T cells and colon cancer progression.

Background: Surgical stress has been suggested to facilitate colon cancer growth and metastasis. However, the precise mechanisms by which surgical trauma promotes colon cancer progression remain poorly understood. Methods: To unravel the mechanisms underlying surgery‐induced colon cancer progression, a syngenic transplantation tumor model was established with CT26 cells, and the effect of laparotomy on tumor progression was investigated. Especially, the expression of several chemokines was assessed, and their roles in recruiting CD4+ CD25+ regulatory T cells (Tregs) after surgery were analyzed. Results: Tregs population was significantly increased in the tumor tissue and peripheral blood of tumor‐bearing mice after laparotomy. C‐C motif chemokine ligand 18 (CCL18) expression was significantly upregulated after laparotomy in tumor tissue and the peritoneal cavity of tumor‐bearing mice, and it was positively correlated with the recruitment of Tregs. Functionally, CCL18 knockdown significantly reduces tumor growth and angiogenesis compared with control. Through analysis of Tregs, we found an upregulated proportion of Tregs in tumor tissue, peritoneal cavity, and peripheral blood after laparotomy, but this enhancement was blocked after CCL18 knockdown. In patients with colon cancer, a higher Tregs proportion is positively correlated to more advanced clinical TNM stages and shorter survival. Furthermore, a positive correlation was found between the serum CCL18 level and the Treg proportion in clinical samples. Conclusion: Surgical trauma contributes to colon cancer progression by increasing CCL18 expression and hence promotes Treg recruitment, which leads to an immunosuppressive environment.

F-box and leucine-rich repeat protein 5 promotes colon cancer progression by modulating PTEN/PI3K/AKT signaling pathway

The hyper-activation of PI3K/AKT signaling is common in many kinds of malignant tumors and promotes cell growth. Moreover, FBXL5 is reported to play an important role in the progression of gastric cancer and cervical cancer. In this view, this study aims to explore the function of FBXL5 in the progression of colon cancer and determine if PI3K/AKT signaling pathway involves in this process. Western blotting, RT-PCR, and immunohistochemistry were used to detect the expression pattern of FBXL5 in colon cancer tissues and cell lines. Immunofluorescence, Duolink, and immunoprecipitation (IP) assays were performed to evaluate the interaction between FBXL5 and PI3K/AKT signaling. Results showed that FBXL5 was elevated in colon cancer tissues and cells, which had physical interaction with PTEN protein and negatively regulated its expression, whereas positively modulated PI3K, AKT and mTOR expression and their phosphorylation. Besides, FBXL5 promoted cell proliferation and tumorigenesis and inhibited apoptosis by modulating PTEN/PI3K/AKT signaling. In conclusion, this study demonstrated that FBXL5 functioned as an oncogene in the progression of colon cancer through regulating PTEN/PI3K/AKT signaling.

Pectin Oligosaccharides Ameliorate Colon Cancer by Regulating Oxidative Stress- and Inflammation-Activated Signaling Pathways.

Colon cancer (CC) is the third common neoplasm worldwide, and it is still a big challenge for exploring new effective medicine for treating CC. Natural product promoting human health has become a hot topic and attracted many researchers recently. Pectin, a complex polysaccharide in plant cell wall, mainly consists of four major types of polysaccharides: homogalacturonan, xylogalacturonan, rhamnogalacturonan I and II, all of which can be degraded into various pectin oligosaccharides (POS) and may provide abundant resource for exploring potential anticancer drugs. POS have been regarded as a novel class of potential functional food with multiple health-promoting properties. POS have antibacterial activities against some aggressive and recurrent bacterial infection and exert beneficial immunomodulation for controlling CC risk. However, the molecular functional role of POS in the prevention of CC risk and progression remains doubtful. The review focuses on antioxidant and anti-inflammatory roles of POS for promoting human health by regulating some potential oxidative and inflammation-activated pathways, such as ATP-activated protein kinase (AMPK), nuclear factor erythroid-2-related factor-2 (Nrf2), and nuclear factor-κB (NF-κB) pathways. The activation of these signaling pathways increases the antioxidant and antiinflammatory activities, which will result in the apoptosis of CC cells or in the prevention of CC risk and progression. Thus, POS may inhibit CC development by affecting antioxidant and antiinflammatory signaling pathways AMPK, Nrf2, and NF-κB. However, POS also can activate signal transduction and transcriptional activator 1 and 3 signaling pathway, which will reduce antioxidant and anti-inflammatory properties and promote CC progression. Specific structural and structurally modified POS may be associated with their functions and should be deeply explored in the future. The present review paper lacks the important information for the linkage between the specific structure of POS and its function. To further explore the effects of prebiotic potential of POS and their derivatives on human immunomodulation in the prevention of CC, the specific POS with a certain degree of polymerization or purified polymers are highly demanded to be performed in clinical practice.

Insulin promotes progression of colon cancer by upregulation of ACAT1

BackgroundInsulin resistant and the progression of cancer is closely related. The aim of this study was to investigate the effect of insulin on the proliferation and migration of colon cancer cells and its underlying mechanism.MethodsColon carcinoma tissues from the 80 cases of colon cancer patients were collected. Immunohistochemistry was used to detect the expression of acyl coenzyme A: cholesterol acyltransferase1 (ACAT1), and we analyzed the correlation between hyperglycemia and ACAT1, hyperglycemia and metastasis. CCK8 assay and transwell assay were used to investigate the effect of different concentrations of insulin and ACAT1siRNA on human colon cancer cell line HT-29. ACAT1 mRNA expression and protein level in HT-29 cells were determined by real-time quantitative PCR and western blotting, respectively.ResultsBiopsies from patients with colon carcinoma showed hyperglycemia links ACAT1, lymph nodes metastasis and distant metastasis. Insulin markedly promoted cell proliferation and migration in human colon cancer HT-29 cells. Moreover, ACAT1mRNA expression and protein level were increased by insulin. ACAT1siRNA resulted in a complete inhibition of the ACAT1 mRNA expression. Consequently insulin-triggered cell proliferation and migration on colon cancer cells were inhibited.ConclusionThe progression of colon cancer has a positive correlation with hyperinsulinemia. Insulin-triggered cell proliferation and metastatic effects on colorectal cancer cells are mediated by ACAT1. Therefore, insulin could promote colon cancer progression by upregulation of ACAT1, which maybe is a potential therapeutic target for colon cancer.

Long non-coding RNA SNHG15 interacts with and stabilizes transcription factor Slug and promotes colon cancer progression

Slug is a fast-turnover transcription factor critical for controlling cell fate and cancer cell invasion and metastasis. The stability of Slug is important and maintained by diverse mechanisms. In this study, we presented a paradigm of this activity by identifying long noncoding RNA (lncRNA) small nucleolar RNA host gene 15 (SNHG15) that binds to and stabilizes Slug in colon cancer cells. LncRNA SNHG15 transcription is upregulated in a variety of human cancers according to The Cancer Genome Atlas. Here, ectopic expression of SNHG15 promoted colon cancer cell migration in vitro, accelerated xenografted tumor growth in vivo, and elevated levels of SNHG15 were associated with poor prognosis for colon cancer patients. Mechanistically, SNHG15 maintains Slug stability in living cells by impeding its ubiquitination and degradation through interaction with the zinc finger domain of Slug. These findings revealed a novel mechanism underlying the control of Slug stability by demonstrating that oncogenic lncRNA SNHG15 interacts with and blocks Slug degradation via the ubiquitin-proteasome system.

Transplantation of placenta-derived multipotent cells in rats with dimethylhydrazine-induced colon cancer decreases survival rate.

Transplantation of placenta-derived multipotent cells (PDMCs) is a promising treatment method for many diseases. However, the impact of PDMCs on colon cancer has not yet been studied. PDMCs were obtained from rat placentas by culturing tissue explants. Colon cancer was experimentally induced in male albino Wistar rats by administering 20 mg/kg dimethylhydrazine (DMH) once a week for 20 consecutive weeks. The administration of the PDMCs was performed at the 20th week after the first DMH injection. The number and size of each tumour lesion were calculated in the 5th week after transplantation. The tumour type was determined by standard histological methods. To study the engraftment of PDMCs in the body of rats, the cells were transduced with enhanced green fluorescent protein. Cell engraftment was determined by assessing the presence of EGFP by PCR and immunohistochemistry. Survival of all rats was monitored daily. Allogeneic transplantation of PDMCs to rats at middle phase of DMH-induced colon carcinogenesis did not significantly influence the number of neoplasms and the parameters of mean and total tumour area, but led to an increase in size of the most invasiveness tumours. Intravenous allogeneic transplantation of PDMCs reduced the survival rate of rats with colon cancer by 17 days. PDMCs from rats engrafted into tissues of the normal intestine, tumours, lungs, liver, and spleen of rats for five weeks after intravenous transplantation. These results suggest that intravenous allogeneic transplantation of PDMCs promotes colon cancer progression and has a negative impact on survival of rats.

Glucagon promotes colon cancer cell growth via regulating AMPK and MAPK pathways.

Cancer is one of the major causes of death in diabetic patients, and an association between antidiabetic drugs and cancer risk has been reported. Such evidence implies a strong connection between diabetes and cancer. Recently, glucagon has been recognized as a pivotal factor implicated in the pathophysiology of diabetes. Glucagon acts through binding to its receptor, glucagon receptor (GCGR), and cross-talk between GCGR-mediated signals and signaling pathways that regulate cancer cell fate has been unveiled. In the current study, expression of GCGR in colon cancer cell lines and colon cancer tissue obtained from patients was demonstrated. Glucagon significantly promoted colon cancer cell growth, and GCGR knockdown with small interfering RNA attenuated the proliferation-promoting effect of glucagon on colon cancer cells. Molecular assays showed that glucagon acted as an activator of cancer cell growth through deactivation of AMPK and activation of MAPK in a GCGR-dependent manner. Moreover, a stable GCGR knockdown mouse colon cancer cell line, CMT93, grew significantly slower than control in a syngeneic mouse model of type 2 diabetes with glycemia and hyperglucagonemia. The present observations provide experimental evidence that hyperglucagonemia in type 2 diabetes promotes colon cancer progression via GCGR-mediated regulation of AMPK and MAPK pathways.

Stromal-derived IGF2 promotes colon cancer progression via paracrine and autocrine mechanisms.

The insulin-like growth factor (IGF)2/IGF1 receptor (IGF1R) signaling axis has an important role in intestinal carcinogenesis and overexpression of IGF2 is an accepted risk factor for colorectal cancer (CRC) development. Genetic amplifications and loss of imprinting contribute to the upregulation of IGF2, but insufficiently explain the extent of IGF2 expression in a subset of patients. Here, we show that IGF2 was specifically induced in the tumor stroma of CRC and identified cancer-associated fibroblasts (CAFs) as the major source. Further, we provide functional evidence that stromal IGF2, via the paracrine IGF1R/insulin receptor axis, activated pro-survival AKT signaling in CRC cell lines. In addition to its effects on malignant cells, autocrine IGF2/IGF1R signaling in CAFs induced myofibroblast differentiation in terms of alpha-smooth muscle actin expression and contractility in floating collagen gels. This was further augmented in concert with transforming growth factor-β (TGFβ) signaling suggesting a cooperative mechanism. However, we demonstrated that IGF2 neither induced TGFβ/smooth muscle actin/mothers against decapentaplegic (SMAD) signaling nor synergized with TGFβ to hyperactivate this pathway in two dimensional and three dimensional cultures. IGF2-mediated physical matrix remodeling by CAFs, but not changes in extracellular matrix-modifying proteases or other secreted factors acting in a paracrine manner on/in cancer cells, facilitated subsequent tumor cell invasion in organotypic co-cultures. Consistently, colon cancer cells co-inoculated with CAFs expressing endogenous IGF2 in mouse xenograft models exhibited elevated invasiveness and dissemination capacity, as well as increased local tumor regrowth after primary tumor resection compared with conditions with IGF2-deficient CAFs. In line, expression of IGF2 correlated with elevated relapse rates and poor survival in CRC patients. In agreement with our results, high-level coexpression of IGF2 and TGFβ was predicting adverse outcome with higher accuracy than increased expression of the individual genes alone. Taken together, we demonstrate that stroma-induced IGF2 promotes colon cancer progression in a paracrine and autocrine manner and propose IGF2 as potential target for tumor stroma cotargeting strategies.

MVP-mediated exosomal sorting of miR-193a promotes colon cancer progression

Exosomes are emerging mediators of intercellular communication; whether the release of exosomes has an effect on the exosome donor cells in addition to the recipient cells has not been investigated to any extent. Here, we examine different exosomal miRNA expression profiles in primary mouse colon tumour, liver metastasis of colon cancer and naive colon tissues. In more advanced disease, higher levels of tumour suppressor miRNAs are encapsulated in the exosomes. miR-193a interacts with major vault protein (MVP). Knockout of MVP leads to miR-193a accumulation in the exosomal donor cells instead of exosomes, inhibiting tumour progression. Furthermore, miR-193a causes cell cycle G1 arrest and cell proliferation repression through targeting of Caprin1, which upregulates Ccnd2 and c-Myc. Human colon cancer patients with more advanced disease show higher levels of circulating exosomal miR-193a. In summary, our data demonstrate that MVP-mediated selective sorting of tumour suppressor miRNA into exosomes promotes tumour progression.

The chromatin-remodeling enzyme BRG1 promotes colon cancer progression via positive regulation of WNT3A.

In this study, we aimed to elucidate the clinical significance and underlying mechanisms of BRG1 in colon cancer. In the clinical analysis, overexpression of BRG1 correlates with colon cancer progression in two cohorts (n = 191 and n = 75). Kaplan-Meier survival analysis revealed that BRG1 is a prognosis predictor for overall survival (P < 0.001) and disease-free survival (P = 0.001). Knocking down BRG1 expression significantly suppressed the proliferation and invasion in colon cancer cells. The expression pattern of WNT3A is consistent with BRG1 in colon cancer tissues and WNT3A expression was inhibited in BRG1 knockdown cells. In addition, restoring WNT3A expression rescues the inhibition of cell proliferation and invasion induced by BRG1. In this study, we demonstrate that BRG1 may contribute to colon cancer progression through upregulating WNT3A expression.

CB2 cannabinoid receptor activation promotes colon cancer progression via AKT/GSK3β signaling pathway.

The pharmacological activation of the cannabinoid receptor type 2, CB2, has been shown to elicit anti-tumoral mechanisms in different cancer types. However, little is known about its endogenous role in tumor pathophysiology, and different studies have attributed pro-tumorigenic properties to this receptor. In a previous work, we showed that CB2 expression is a poor prognostic factor in colon cancer patients. Here we report that activation of CB2 with low doses of specific agonists induce cell proliferation and favor the acquisition of aggressive molecular features in colon cancer cells. We show that sub-micromolar concentrations of CB2-specific agonists, JWH-133 and HU-308, promote an increase in cell proliferation rate through the activation of AKT/PKB pathway in colon cancer in vitro and in vivo. AKT activation promotes GSK3β inhibition and thus, a more aggressive cell phenotype with the subsequent elevation of SNAIL levels, E-cadherin degradation and β-catenin delocalization from cell membrane. Taken together, our data show that CB2 activation with sub-micromolar doses of agonists, which could be more similar to endogenous levels of cannabinoids, promote colon cancer progression, implicating that CB2 could have a pro-tumorigenic endogenous role in colon cancer.

Loss of TGFβ signaling promotes colon cancer progression and tumor-associated inflammation.

TGFβ has both tumor suppressive and tumor promoting effects in colon cancer. Also, TGFβ can affect the extent and composition of inflammatory cells present in tumors, contextually promoting and inhibiting inflammation. While colon tumors display intratumoral inflammation, the contributions of TGFβ to this process are poorly understood. In human patients, we found that epithelial loss of TGFβ signaling was associated with increased inflammatory burden; yet overexpression of TGFβ was also associated with increased inflammation. These findings were recapitulated in mutant APC models of murine tumorigenesis, where epithelial truncation of TGFBR2 led to lethal inflammatory disease and invasive colon cancer, mediated by IL8 and TGFβ1. Interestingly, mutant APC mice with global suppression of TGFβ signals displayed an intermediate phenotype, presenting with an overall increase in IL8-mediated inflammation and accelerated tumor formation, yet with a longer latency to the onset of disease observed in mice with epithelial TGFBR-deficiency. These results suggest that the loss of TGFβ signaling, particularly in colon epithelial cells, elicits a strong inflammatory response and promotes tumor progression. This implies that treating colon cancer patients with TGFβ inhibitors may result in a worse outcome by enhancing inflammatory responses.

Abstract B15: Transforming growth factor β type III (TβRIII/Betaglycan) suppresses canonical Wnt signaling in ovarian cancer

Abstract Ovarian cancer remains the deadliest gynecologic malignancy and the fifth leading cause of death from cancer in women[1]. Transforming growth factor β Type III (TβRIII/Betaglycan) receptor is a ubiquitously expressed co-receptor for the TGF-β ligand superfamily[2] whose expression is significantly decreased or lost in human epithelial ovarian tumors compared to normal tissue, with loss of TβRIII expression correlating with tumor grade and ovarian cancer progression[3]. TβRIII has increasing roles in suppressing cancer progression via cell motility[4], cell adhesion[5], and cell differentiation[2], largely independent of its TGF-β co-receptor functions[2, 3]. Structurally, TβRIII is a transmembrane proteoglycan containing both heparan sulfate and chondroitin sulfate glycosaminoglycan (GAG) chain modifications in its extracellular domain[5] that can interact with non-TGF-β family members, namely FGF2, via its GAG chains to regulate tumorigenesis[2].There is increasing evidence that Wnt glycoproteins that play complex roles in cancer[1, 6-11] have a high affinity for GAG chains on proteoglycans[12, 13]. Thus, we have initiated studies to determine the possible role of TβRIII on canonical Wnt3a signaling in ovarian cancer. Using a combination of cell signaling and biochemical approaches in ovarian cancer models, we find that TβRIII suppresses Wnt3a signaling by binding Wnt3a via its heparan sulfated GAG chains, which leads to perturbation of the LRP6/Frizzled/Wnt3a complex required for Wnt3a signaling activation. Reciprocal overexpression and knockdown of TβRIII in ovarian cancer cell lines reveal that TβRIII is a strong suppressor of canonical Wnt3a signaling, largely independent of TβRIII’s role as a TGF-β co-receptor. Finally, we provide evidence, via TCF/LEF-sensitive reporter activity[14], that TβRIII chondroitin sulfate chains can promote Wnt3a signaling in the absence of its heparan sulfate chains. These results indicate an intricate mode of Wnt3a signaling regulation by TβRIII/Betaglycan, mediated by distinct functions of its heparan and chondroitin chains. Our studies suggest a critical role for TβRIII’s heparan and chondroitin sulfated GAG modifications in modulating Wnt3a signaling and, more importantly, a possible therapeutic approach to address malfunctions in the Wnt signaling pathways that lead to ovarian carcinogenesis. Citations: 1. Arend, R.C., et al., The Wnt/beta-catenin pathway in ovarian cancer: a review. Gynecol Oncol, 2013. 131(3): p. 772-9. 2. Knelson, E.H., et al., Type III TGF-beta receptor promotes FGF2-mediated neuronal differentiation in neuroblastoma. J Clin Invest, 2013. 123(11): p. 4786-98. 3. Gatza, C.E., S.Y. Oh, and G.C. Blobe, Roles for the type III TGF-beta receptor in human cancer. Cell Signal, 2010. 22(8): p. 1163-74. 4. Mythreye, K., et al., TbetaRIII/beta-arrestin2 regulates integrin alpha5beta1 trafficking, function, and localization in epithelial cells. Oncogene, 2013. 32(11): p. 1416-27. 5. Mythreye, K. and G.C. Blobe, Proteoglycan signaling co-receptors: roles in cell adhesion, migration and invasion. Cell Signal, 2009. 21(11): p. 1548-58. 6. Tung, E.K., et al., Upregulation of the Wnt co-receptor LRP6 promotes hepatocarcinogenesis and enhances cell invasion. PLoS One, 2012. 7(5): p. e36565. 7. Qi, L., et al., Wnt3a expression is associated with epithelial-mesenchymal transition and promotes colon cancer progression. J Exp Clin Cancer Res, 2014. 33(1): p. 107. 8. Lavergne, E., et al., Blocking Wnt signaling by SFRP-like molecules inhibits in vivo cell proliferation and tumor growth in cells carrying active beta-catenin. Oncogene, 2011. 30(4): p. 423-33. 9. Verras, M., et al., Wnt3a growth factor induces androgen receptor-mediated transcription and enhances cell growth in human prostate cancer cells. Cancer Res, 2004. 64(24): p. 8860-6. 10. Gatcliffe, T.A., et al., Wnt signaling in ovarian tumorigenesis. Int J Gynecol Cancer, 2008. 18(5): p. 954-62. 11. Boyer, A., A.K. Goff, and D. Boerboom, WNT signaling in ovarian follicle biology and tumorigenesis. Trends Endocrinol Metab, 2010. 21(1): p. 25-32. 12. Ai, X., et al., QSulf1 remodels the 6-O sulfation states of cell surface heparan sulfate proteoglycans to promote Wnt signaling. J Cell Biol, 2003. 162(2): p. 341-51. 13. Capurro, M., et al., Glypican-3 binds to Frizzled and plays a direct role in the stimulation of canonical Wnt signaling. J Cell Sci, 2014. 127(Pt 7): p. 1565-75. 14. Veeman, M.T., et al., Zebrafish prickle, a modulator of noncanonical Wnt/Fz signaling, regulates gastrulation movements. Curr Biol, 2003. 13(8): p. 680-5. Citation Format: Laura M. Jenkins, Archana Varadaraj, Haley Flores, Mythreye Karthikeyan. Transforming growth factor β type III (TβRIII/Betaglycan) suppresses canonical Wnt signaling in ovarian cancer. [abstract]. In: Proceedings of the AACR Special Conference: Developmental Biology and Cancer; Nov 30-Dec 3, 2015; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(4_Suppl):Abstract nr B15.