Insulin-like growth factor-I receptor blockade reduces the invasiveness of gastrointestinal cancers via blocking production of matrilysin

Lessons to Learn for Adequate Targeted Therapy Development in Metastatic Colorectal Cancer Patients

Insulin-like growth factor 1 receptor (IGF1R) is a receptor tyrosine kinase that regulates cell growth and proliferation. Upregulation of the IGF1R pathway constitutes a common paradigm shared with other receptor tyrosine kinases such as EGFR, HER2, and MET in different cancer types, including colon cancer. The main IGF1R signaling pathways are PI3K-AKT and MAPK-MEK. However, different processes, such as post-translational modification (SUMOylation), epithelial-to-mesenchymal transition (EMT), and microenvironment complexity, can also contribute to intrinsic and acquired resistance. Here, we discuss new strategies for adequate drug development in metastatic colorectal cancer patients.

Insulin-like Growth Factor-1, Insulin-like Growth Factor Binding Protein-3 and the Incidence of Malignant Neoplasms in a Nested Case-Control Study

Insulin-like growth factor (IGF)-1 is a potent mitogen, but IGF binding protein (IGFBP)-3 inhibits IGF1. To elucidate the relationship between both IGF1 and IGFBP and the risk of tumorigenesis, the association between IGF1 and IGFBP3 serum levels and of malignant tumor incidence was investigated in a prospective case-control study nested in the Japan Collaborative Cohort Study. A baseline survey was started in 1988-1990, 110,585 subjects were enrolled, and 35% of participants donated blood samples. Those who had been diagnosed with malignant tumors by 1997 were considered cases. The analysis involved 1,349 cases and 4,012 controls. Conditional logistic regression was used to estimate ORs for cancer incidence associated with IGF-related molecules. After controlling for alcohol intake, body mass index (BMI), and smoking, participants with high total-IGFBP3 and free-IGFBP3, which is estimated by the molar difference of (IGFBP3 - IGF1), had a risk of future neoplasms (P trend = 0.014 and 0.009, respectively), but those with IGF1 did not. People in the second to fifth quintiles had a lower risk than those in the first quintile (ORs 0.676-0.736 and 0.657-0.870, respectively). Limiting subjects to those followed for 3 years weakened the negative associations of total- and free-IGFBP3, whereas a positive relationship of free-IGF1, which was estimated by the molar ratio of IGF1/IGFBP3, was seen (P trend = 0.004, 0.002, and 0.013, respectively). After controlling for alcohol intake, smoking, BMI, and diabetes mellitus, the results were confirmed. These findings suggest that serum IGF1 and IGFBP3 are related to future risk of malignant neoplasms.

Circulating insulin-like growth factor binding protein-3 and risk of gastrointestinal malignant tumors

BACKGROUND AND AIM

Insulin-like growth factor-1 (IGF1) is a potent mitogen and is inhibited by IGF-binding protein-3 (IGFBP3). High serum IGF1 and low IGFBP3 are associated with increased risk of several carcinomas. Here, we assessed the relationship of these peptides with the risk of gastrointestinal malignancies, in a prospective case-control study nested in the Japan Collaborative Cohort Study.

METHODS

The analysis involved 916 cases who had been diagnosed as gastrointestinal malignancies (C15-25) and 2306 controls. To estimate odds ratios for incidence of malignancies associated with these levels, a conditional logistic model was used.

RESULTS

Both higher total and free IGFBP3 were associated with a decreased risk of tumor (P for trend < 0.001 and = 0.003, respectively). People in the second to fifth quintiles had lower risk compared to the first quintile (odds ratios ranged 0.532-0.650 and 0.582-0.725, respectively). After adjustment for IGF1, body mass index, drinking, and smoking, total IGFBP3 was inversely correlated with cancer risk (P for trend = 0.031). After adjustment, free IGFBP3 was inversely associated with the risk (P for trend = 0.007). Although total IGF1 was inversely correlated with tumor risk, it was not after controlling for IGFBP3 (P for trend = 0.007 and 0.589, respectively). Free IGF1 was not associated with the risk (P for trend = 0.361). Limiting subjects to those followed for over 3 years reinforced the inverted relationships of total and free IGFBP3 with risk for tumors (P for trend = 0.005 and 0.008, respectively).

CONCLUSION

Both total and free IGFBP3 may be inversely associated with the incidence of gastrointestinal malignancies.

Activation of IGF1R by DARPP-32 promotes STAT3 signaling in gastric cancer cells

Dopamine and cAMP-regulated phosphoprotein, Mr 32000 (DARPP-32), is frequently overexpressed in early stages of gastric cancers. We utilized in vitro assays, 3D gastric gland organoid cultures, mouse models, and human tissue samples to investigate the biological and molecular impact of DARPP-32 on activation of IGF1R and STAT3 signaling and gastric tumorigenesis. DARPP-32 enhanced phosphorylation of IGF1R (Y1135), a step that was critical for STAT3 phosphorylation at Y705, nuclear localization, and transcription activation. By using proximity ligation and co-immunoprecipitation assays, we found that IGF1R and DARPP-32 co-existed in the same protein complex. Binding of DARPP-32 to IGF1R promoted IGF1R phosphorylation with subsequent activation of downstream SRC and STAT3. Analysis of gastric tissues from the TFF1 knockout (KO) mouse model of gastric neoplasia, demonstrated phosphorylation of STAT3 in the early stages of gastric tumorigenesis. By crossing the TFF1 KO mice with DARPP-32 (DP) knockout (KO) mice, that have normal stomach, we obtained double knockout (TFF1 KO/DP KO). The gastric mucosa from the double KO mice did not show phosphorylation of IGF1R or STAT3. In addition, the TFF1 KO/DP KO mice had a significant delay in developing neoplastic gastric lesions. Analysis of human gastric cancer tissue microarrays, showed high levels of DARPP-32 and positive immunostaining for nuclear STAT3 in cancer tissues, as compared to non-cancer histologically normal tissues. In summary, the DARPP-32-IGF1R signaling axis plays a key role in regulating the STAT3 signaling, a critical step in gastric tumorigenesis.

Coexpression of p-IGF-1R and MMP-7 Modulates Panitumumab and Cetuximab Efficacy in RAS Wild-Type Metastatic Colorectal Cancer Patients

INTRODUCTION

The coexpression of pIGF-1R and MMP-7 (double-positive phenotype, DP) correlates with poor overall survival (OS) in KRAS wild-type (WT) (exon 2) metastatic colorectal cancer (mCRC) patients treated with irinotecan-cetuximab in second/third line.

METHODS

We analyzed two prospective biomarker design trials of newly diagnosed RAS-WT mCRC patients treated with panitumumab-FOLFOX6 (PULSE trial; NCT01288339) or cetuximab plus either FOLFOX6/FOLFIRI (POSIBA trial; NCT01276379). The main exposure was DP phenotype (DP/non-DP), as assessed by two independent pathologists. DP cases were defined by immunohistochemistry as >70% expression of moderate or strong intensity for both MMP-7 and pIGF-1R. Primary endpoint: progression-free survival (PFS); secondary endpoints: OS and response rate. PFS and OS were adjusted by baseline characteristics using multivariate Cox models.

RESULTS

We analyzed 67 patients (30 non-DP, 37 DP) in the PULSE trial and 181 patients in the POSIBA trial (158 non-DP, 23 DP). Response rates and PFS were similar between groups in both studies. DP was associated with prolonged OS in PULSE (adjusted HR: 0.23; 95%CI: 0.11-0.52; P=.0004) and with shorter OS in POSIBA (adjusted HR: 1.67; 95%CI: 0.96-2.90; P=.07).

CONCLUSION

A differential effect of anti-EGFRs on survival by DP phenotype was observed. Panitumumab might be more beneficial for RAS-WT mCRC patients with DP phenotype, whereas cetuximab might improve OS in non-DP.

Matrix metalloproteinase (MMP)-7 in Barrett's esophagus and esophageal adenocarcinoma: expression, metabolism, and functional significance

Matrix metalloproteinase (MMP)-7, unlike many MMPs, is typically expressed in epithelial cells. It has been linked to epithelial responses to infection, injury, and tissue remodeling including the progression of a number of cancers. We have now examined how MMP-7 expression changes in the progression to esophageal adenocarcinoma (EAC), and have studied mechanisms regulating its expression and its functional significance. Immunohistochemistry revealed that MMP-7 was weakly expressed in normal squamous epithelium adjacent to EAC but was abundant in epithelial cells in both preneoplastic lesions of Barrett's esophagus and EAC particularly at the invasive front. In the stroma, putative myofibroblasts expressing MMP-7 were abundant at the invasive front but were scarce or absent in adjacent tissue. Western blot and ELISA revealed high constitutive secretion of proMMP-7 in an EAC cell line (OE33) that was inhibited by the phosphatidylinositol (PI) 3-kinase inhibitor LY294002 but not by inhibitors of protein kinase C, or MAP kinase activation. There was detectable proMMP-7 in cultured esophageal myofibroblasts but it was undetectable in media. Possible metabolism of MMP-7 by myofibroblasts studied by proteomic analysis indicated degradation via extensive endopeptidase, followed by amino- and carboxpeptidase, cleavages. Myofibroblasts exhibited increased migration and invasion in response to conditioned media from OE33 cells that was reduced by MMP-7 knockdown and immunoneutralization. Thus, MMP-7 expression increases at the invasive front in EAC which may be partly attributable to activation of PI 3-kinase. Secreted MMP-7 may modify the tumor microenvironment by stimulating stromal cell migration and invasion.

Type I insulin-like growth factor receptor signaling in hematological malignancies

The insulin-like growth factor (IGF) signaling system plays key roles in the establishment and progression of different types of cancer. In agreement with this idea, substantial evidence has shown that the type I IGF receptor (IGF-IR) and its primary ligand IGF-I are important for maintaining the survival of malignant cells of hematopoietic origin. In this review, we discuss current understanding of the role of IGF-IR signaling in cancer with a focus on the hematological neoplasms. We also address the emergence of IGF-IR as a potential therapeutic target for the treatment of different types of cancer including plasma cell myeloma, leukemia, and lymphoma.

The effect of forced expression of mutated K-RAS gene on gastrointestinal cancer cell lines and the IGF-1R targeting therapy

Mutation in K-RAS (K-RAS-MT) plays important roles in both cancer progression and resistance to anti-epidermal growth factor receptor (EGFR) therapy in gastrointestinal tumors. Insulin-like growth factor-1 receptor (IGF-1R) signaling is required for carcinogenicity and progression of many tumors as well. We have previously shown successful therapy for gastrointestinal cancer cell lines bearing a K-RAS mutation using an anti-IGF-1R monoclonal antibody. In this study, we sought to evaluate effects of forced K-RAS-MT expression on gastrointestinal cancer cell lines representing a possible second resistance mechanism for anti-EGFR therapy and IGF-1R-targeted therapy for these transfectants. We made stable transfectants of K-RAS-MT in two gastrointestinal cancer cell lines, colorectal RKO and pancreatic BxPC-3. We assessed the effect of forced expression of K-RAS-MT on proliferation, apoptosis, migration, and invasion in gastrointestinal cancer cells. Then we assessed anti-tumor effects of dominant negative IGF-1R (IGF-1R/dn) and an IGF-1R inhibitor, picropodophyllin, on the K-RAS-MT transfectants. Overexpression of K-RAS-MT in gastrointestinal cancer cell lines led to more aggressive phenotypes, with increased proliferation, decreased apoptosis, and increased motility and invasion. IGF-1R blockade suppressed cell growth, colony formation, migration, and invasion, and up-regulated chemotherapy-induced apoptosis of gastrointestinal cancer cells, even when K-RAS-MT was over-expressed. IGF-1R blockade inhibited the Akt pathway more than the extracellular signal-regulated kinase (ERK) pathway in the K-RAS-MT transfectants. IGF-1R/dn, moreover, inhibited the growth of murine xenografts expressing K-RAS-MT. Thus, K-RAS-MT might be important for progressive phonotype observed in gastrointestinal cancers. IGF-1R decoy is a candidate molecular therapeutic approach for gastrointestinal cancers even if K-RAS is mutated. © 2016 Wiley Periodicals, Inc.

The expression of IGF-1R in Helicobacter pylori-infected intestinal metaplasia and gastric cancer

Overexpression of IGF-1R has been demonstrated in gastrointestinal cancers, and its expression is reported as the result of the loss of tumor suppressors. IL-16 is involved in the pathophysiological process of chronic inflammatory diseases. The aim of this study is to determine the changes in the expression of IGF-1R in intestinal metaplasia (IM) and gastric cancer (GC) as well as the effect of Helicobacter pylori (H. pylori) and IL-16 on cell proliferation and IGF-1R expression in gastric cells. AGS cells were incubated with combinations of IL-16 and H. pylori. Gastric cell proliferation was studied by BrdU uptake. In H. pylori infected mucosa, IGF-1R was significantly higher in IM than chronic gastritis (CG), and also higher in GC than CG and IM. H. pylori significantly decreased BrdU uptake. IL-16 increased BrdU uptake and IGF-1R on AGS cells which had been decreased by H. pylori. Co-incubation with IL-16 increased the expression of IGF-1R mRNA in H. pylori infected cells. We conclude that the expression of IGF-1R in H. pylori infected gastric mucosa may indicate an early stage of carcinogenesis. The IL-16 secretion by H. pylori can be a trigger for the expression of IGF-1R, and it may also be a factor for gastric carcinogenesis.

Clinical significance of IGF1R gene expression in patients with Stage II/III gastric cancer who receive curative surgery and adjuvant chemotherapy with S-1

PURPOSE

Curative resection and adjuvant chemotherapy is the standard treatment for Stage II/III gastric cancer, and S-1 is widely used for adjuvant chemotherapy. The type 1 insulin-like growth factor receptor (IGF1R) is involved in cell proliferation and prevention of apoptosis in many tumors. We evaluated the relative expression of the IGF1R gene to determine whether such expression correlates with outcomes in patients with Stage II/III gastric cancer.

METHODS

We measured the expression levels of the IGF1R gene in specimens of cancer and adjacent normal mucosa obtained from 134 patients with Stage II/III gastric cancer who received curative resection and adjuvant chemotherapy with S-1. We then evaluated whether the IGF1R gene expression levels correlate with clinicopathological characteristics and outcomes.

RESULTS

IGF1R mRNA expression levels tended to be higher in cancer tissue than in the normal adjacent mucosa (P = 0.078). Multivariate analysis showed that high IGF1R gene expression was a significant independent predictor of poor survival in Stage II/III gastric cancer after curative resection and adjuvant chemotherapy with S-1 (HR 3.681, P = 0.007). The overall survival rate was significantly lower in patients with high IGF1R gene expression than in those with low expression (P = 0.012).

CONCLUSIONS

IGF1R overexpression is considered a useful independent predictor of outcomes in Stage II/III gastric cancer after curative resection and adjuvant chemotherapy with S-1.

MMP2 and MMP7 at the invasive front of gastric cancer are not associated with mTOR expression

BACKGROUND

Regulation of MMP expression by activation of mTOR signalling has been demonstrated for several tumor types, but has thus far not been confirmed in gastric cancer.

FINDINGS

The study compromised 128 patients who underwent gastric resection for cancer (66.4 % male; 86 intestinal, 42 diffuse type). Immunohistochemical staining of MMPs was performed to analyse the topographical pattern of MMP expression at the tumor center and the invasive front, respectively. MMP2 showed higher expression at the invasive front compared to the tumor center, whereas MMP7 staining scores were higher in the tumor center, and there was no difference for MMP9. The expression of p-mTOR was higher in the tumor center than at the invasive front, with a similar trend for mTOR. For intestinal type gastric cancer there was a weak correlation of MMP9 with expression of mTOR in the tumor center. Otherwise, there was no correlation of the MMPs with mTOR. By treatment of MKN45 gastric cancer cells with rapamycin, a reduction of p-mTOR in the Western blot was achieved; however, expression of MMPs remained unaffected.

CONCLUSIONS

Expression of MMP2 and MMP7 in gastric cancer is not associated with mTOR, MMP9 expression might be related to mTOR signalling in a subset of tumors.

Molecular Targets in Biliary Carcinogenesis and Implications for Therapy

Biliary tract cancers (BTCs) encompass a group of invasive carcinomas, including cholangiocarcinoma (intrahepatic, perihilar, or extrahepatic), and gallbladder carcinoma. Approximately 90% of patients present with advanced, unresectable disease and have a poor prognosis. The latest recommendation is to treat advanced or metastatic disease with gemcitabine and cisplatin, although chemotherapy has recorded modest survival benefits. Comprehension of the molecular basis of biliary carcinogenesis has resulted in experimental trials of targeted therapies in BTCs, with promising results. This review addresses the emerging role of targeted therapy in the treatment of BTCs. Findings from preclinical studies were reviewed and correlated with the outcomes of clinical trials that were undertaken to translate the laboratory discoveries.

IMPLICATIONS FOR PRACTICE

Biliary tract cancers are rare. Approximately 90% of patients present with advanced, unresectable disease and have a poor prognosis. Median overall and progression-free survival are 12 and 8 months, respectively. Because chemotherapy has recorded modest survival benefits, targeted therapies are being explored for personalized treatment of these cancers. A comprehensive review of targeted therapies in biliary tract cancers was undertaken to present emerging evidence from laboratory and/or molecular studies as they translate to clinical trials and outcomes. The latest evidence on this topic is presented to clinicians and practitioners to guide decisions on treatment of this disease.

MALAT2-activated long noncoding RNA indicates a biomarker of poor prognosis in gastric cancer

The purpose of this study is to investigate the role of the long noncoding RNA metastasis associated lung adenocarcinoma transcript 2 (MALAT2) in the prognosis of stage II/III gastric cancer (GC) patients. The expression of MALAT2 was evaluated in cancer tissues from 146 stage II/III GC patients undergoing radical resection and 60 paired normal samples using quantitative real-time reverse transcriptase PCR. Differences in the expression of MALAT2 between 23 GC and paired normal colonic mucosa samples were analysed with the Wilcoxon test. Relationships between the expression level of MALAT2, patient clinico-pathological parameters and disease-free survival and overall survival were analysed using the uni-variate Kaplan-Meier method and the multivariate COX regression model. The quantitative polymerase chain reaction results showed that MALAT2 was frequently over-expressed in cancer tissues and this over-expression was found to significantly correlate with lymph node metastasis and tumor stage. The ectopic expression of MALAT2 contributed to the migration of human GC SGC-7901 cells, whereas knockdown of MALAT2 inhibited the migration of the SGC-7901 cells in vitro. Further investigation into the underlying mechanisms responsible for the migratory effects revealed that MALAT2 induced the epithelial-mesenchymal transition (EMT) through an MEK/extracellular signal-regulated kinase-dependent mechanism as treatment with the MEK inhibitor, U0126, decreased migration and reversed the EMT in the MALAT2 over-expressed SGC-7901 cells. The expression of MALAT2 is upregulated in GC tissues, and a higher expression level of MALAT2 might serve as a negative prognostic marker in stage II/III GC patients which implies the potential application of MALAT2 in the therapeutic treatment of GC.Cancer Gene Therapy advance online publication, 27 February 2015; doi:10.1038/cgt.2015.6.

MMP-9 is increased in the pathogenesis of gastric cancer by the mediation of HER2

Human epidermal growth factor receptor 2 (HER2) overexpression is not only closely associated with the tumor growth, but is also related to tumor invasion. We here aimed to investigate the mechanism of HER2 mediation in the pathogenesis of gastric cancer. The human gastric cancer cell lines SGC-7901, MKN-45, AGS, the immortalized cell line GES-1 derived from normal gastric mucosa. Cell transfection and selection of stable cell lines and the gene and protein levels of HER2 and Matrix metalloproteinase-9 (MMP-9) were examined to determine the molecular relationship between them in the pathogenesis of gastric cancer. The human gastric cancer cell lines SGC-7901, MKN-45, AGS, the immortalized cell line GES-1 derived from normal gastric mucosa. Cell transfection and selection of stable cell lines and the gene and protein levels of HER2 and MMP-9 were examined to determine the molecular relationship between them in the pathogenesis of gastric cancer. We demonstrated that vector-based shRNA significantly knocked down the expression of HER2 and considerably inhibited both the migration and invasion of gastric cancer cells. HER2 knockdown resulted in the downregulation of the expression of MMP-9, whereas HER2 overexpression improved the transcription of MMP-9 through the activation of an MMP-9 promoter. The promoter region of MMP-9 between -2500 and -2000 bp was found to be crucial for the upregulation of HER2-mediated transcription. Furthermore, a truncated promoter (-70 to +63) did not display any transcriptional activity. Cell invasion activity was almost completely inhibited when MMP-9 was knocked down. Conversely, the overexpression of MMP-9 partly rescued the invasion ability of cell strains with knockdown HER2. These findings help further understanding of the molecular mechanisms through which HER2 promotes malignancy, and suggest that targeting both HER2 and MMP-9 may be required to effectively block HER2 signaling in gastric cancer therapy.

HER-2-induced PI3K signaling pathway was involved in the pathogenesis of gastric cancer

Human epidermal growth factor receptor-2 (HER-2) overexpression was closely associated with the tumor growth and invasion, we here aimed to investigate the mechanism of HER-2 mediation in the pathogenesis of gastric cancer (GC). We first detected the expression of HER-2 in GC cell line SGC-7901 and then examined the levels of nuclear factor-κB (NF-κB), matrix metalloproteinase-9 (MMP-9) and intercellular adhesion molecule-1 (ICAM-1) and the association between them by molecular methods. Statistical analysis was used to compare the significance. We further detected the possible molecular mechanism involved in their relationship in the SGC-7901 genesis. The MMP-9, NF-κB and secretory type (s-ICAM-1) levels were significantly greater in peripheral blood serum from SGC-7901 than healthy control GES-1 (P<0.01). ICAM-1, MMP-9 and NF-κB mRNA and protein levels were more highly expressed in SGC-7901 than healthy control GES-1. The expression levels of NF-κB, MMP-9 and ICAM-1 were positively related in GC cell line SGC-7901, which was HER-2 positive. The HER-2 positive SGC-7901 secreted more transforming growth factor beta 1 (TGF-β1) and resultantly activated MMP-9 to enhance s-ICAM-1 secretion and further studies showed that phosphatidylinositol-3 kinase (PI3K)/Akt/NF-κB signaling pathway was involved in GC pathogenesis. The GC cells that express the HER-2 oncogene spur the activation of NF-κB that can upregulate the expression of ICAM-1 and induce the expression of MMP-9, which hydrolyzes ICAM-1 into s-ICAM-1 to promote tumor immune escape. TGF-β1-induced PI3K/Akt/NF-κB signaling pathway was involved in the pathogenesis of GC and they could be a new target for cancer therapy. The GC cells that express the HER-2 oncogene spur the activation of NF-κB that can upregulate the expression of ICAM-1 and induce the expression of MMP-9, which hydrolyzes ICAM-1 into s-ICAM-1 to promote tumor immune escape. TGF-β1-induced PI3K/Akt/NF-κB signaling pathway was involved in the pathogenesis of GC and they could be a new target for cancer therapy.

Insulin-like growth factor pathway aberrations and gastric cancer; evaluation of prognostic significance and assessment of therapeutic potentials

Gastric cancer is a major cause of treatment-related mortality and morbidity worldwide, it ranks as the fourth most common cause of cancer-related death in males and fifth most common cause of cancer-related death in women. The prognosis of advanced cases with gastric cancer looks poor with the majority dying within 1 year of diagnosis of metastatic disease. Thus, intensive search for new innovative treatments has been a major focus of current oncology research. Insulin-like growth factor (IGF) pathway has been evaluated extensively in preclinical settings of gastric cancer. Initially, a number of studies have shown a potential role for aberrant tissue expression of IGFR-related markers in the process of gastric carcinogenesis, and a number of other studies have shown a clear association between IGFR expression and aggressive histopathological subtypes. However, clinical introduction of IGFR inhibitors into gastric cancer treatment has been delayed compared to other solid tumors. This review provides concise evaluation of prognostic significance of IGF pathway-related markers in gastric cancer with assessment of potential therapeutic strategies.

Insulin-like growth factor-I induces epithelial to mesenchymal transition via GSK-3β and ZEB2 in the BGC-823 gastric cancer cell line

Metastasis is the most common cause of mortality in patients with gastric cancer. Epithelial-to-mesenchymal transition (EMT), which may be stimulated by insulin-like growth factor-I (IGF-I) is involved in the metastasis of numerous tumors; however, the molecular mechanism by which IGF-I may induce tumor cell EMT remains to be elucidated in gastric cancer. The present study aimed to investigate the induction of EMT in BGC-823 gastric cancer cells. It was identified that IGF-I induced EMT by upregulating the levels of ZEB2 transcription factor, and this was dependent on the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway in these cells. In addition, glycogen synthase kinase 3β (GSK-3β), an intracellular downstream effector of PI3K/Akt, sustained the epithelial phenotype by repressing ZEB2 expression and the subsequent inhibition of EMT induced by IGF-I, suggesting the involvement of a potential PI3K/Akt-GSK-3β-ZEB2 signaling pathway in IGF-I-induced EMT in gastric cancer BGC-823 cells. Overall, the results of the present study suggest that IGF-I induced EMT by the activation of a PI3K/Akt-GSK-3β-ZEB2 signaling pathway in gastric cancer BGC-823 cells. Therefore, this study may provide more useful information regarding the mechanism of gastric cancer metastasis.

MicroRNA-206 suppresses gastric cancer cell growth and metastasis

Gastric cancer is one of the leading causes of cancer death world-wide and carries a high rate of metastatic risk. In addition to other protein-coding oncogenes and tumor suppressor genes, microRNAs play an important role in gastric cancer tumorigenic progression. Here, we show that miR-206 is expressed at markedly low levels in a cohort of gastric tumors compared to their matching normal tissues, and in a number of gastric cancer cell lines. Down-regulation of miR-206 was particularly significant in tumors with lymphatic metastasis, local invasion, and advanced TNM staging. We find that forced expression of miR-206 suppressed the proliferation, colony-formation, and xenograft tumorigenesis of SCG-7901 cells, a line of gastric cancer cells. Forced expression of miR-206 also suppressed SCG-7901 cell migration and invasion, as well as metastasis in cell culture or tail-vein injected mouse models, respectively. The anti-metastatic effect of miR-206 is likely mediated by targeting metastasis regulatory genes STC2, HDAC4, KLF4, IGF1R, FRS2, SFRP1, BCL2, BDNF, and K-ras, which were drastically down-regulated by stable expression of exogenous miR-206 in SCG-7901 cells. Taken together, our results indicate that miR-206 is a tumor suppressor of gastric cancer acting at steps that regulate metastasis.

An updated review of gastric cancer in the next-generation sequencing era: Insights from bench to bedside and vice versa

Gastric cancer (GC) is one of the most common malignancies and remains the second leading cause of cancer-related death worldwide. There is an increasing understanding of the roles that genetic and epigenetic alterations play in GCs. Recent studies using next-generation sequencing (NGS) have revealed a number of potential cancer-driving genes in GC. Whole-exome sequencing of GC has identified recurrent somatic mutations in the chromatin remodeling gene ARID1A and alterations in the cell adhesion gene FAT4, a member of the cadherin gene family. Mutations in chromatin remodeling genes (ARID1A, MLL3 and MLL) have been found in 47% of GCs. Whole-genome sequencing and whole-transcriptome sequencing analyses have also discovered novel alterations in GC. Recent studies of cancer epigenetics have revealed widespread alterations in genes involved in the epigenetic machinery, such as DNA methylation, histone modifications, nucleosome positioning, noncoding RNAs and microRNAs. Recent advances in molecular research on GC have resulted in the introduction of new diagnostic and therapeutic strategies into clinical settings. The anti-human epidermal growth receptor 2 (HER2) antibody trastuzumab has led to an era of personalized therapy in GC. In addition, ramucirumab, a monoclonal antibody targeting vascular endothelial growth factor receptor (VEGFR)-2, is the first biological treatment that showed survival benefits as a single-agent therapy in patients with advanced GC who progressed after first-line chemotherapy. Using NGS to systematically identify gene alterations in GC is a promising approach with remarkable potential for investigating the pathogenesis of GC and identifying novel therapeutic targets, as well as useful biomarkers. In this review, we will summarize the recent advances in the understanding of the molecular pathogenesis of GC, focusing on the potential use of these genetic and epigenetic alterations as diagnostic biomarkers and novel therapeutic targets.

Diabetes and gastric cancer: the potential links

This article reviews the epidemiological evidence linking diabetes and gastric cancer and discusses some of the potential mechanisms, confounders and biases in the evaluation of such an association. Findings from four meta-analyses published from 2011 to 2013 suggest a positive link, which may be more remarkable in females and in the Asian populations. Putative mechanisms may involve shared risk factors, hyperglycemia, Helicobacter pylori (H. pylori) infection, high salt intake, medications and comorbidities. Diabetes may increase the risk of gastric cancer through shared risk factors including obesity, insulin resistance, hyperinsulinemia and smoking. Hyperglycemia, even before the clinical diagnosis of diabetes, may predict gastric cancer in some epidemiological studies, which is supported by in vitro, and in vivo studies. Patients with diabetes may also have a higher risk of gastric cancer through the higher infection rate, lower eradication rate and higher reinfection rate of H. pylori. High salt intake can act synergistically with H. pylori infection in the induction of gastric cancer. Whether a higher risk of gastric cancer in patients with diabetes may be ascribed to a higher intake of salt due to the loss of taste sensation awaits further investigation. The use of medications such as insulin, metformin, sulfonylureas, aspirin, statins and antibiotics may also influence the risk of gastric cancer, but most of them have not been extensively studied. Comorbidities may affect the development of gastric cancer through the use of medications and changes in lifestyle, dietary intake, and the metabolism of drugs. Finally, a potential detection bias related to gastrointestinal symptoms more commonly seen in patients with diabetes and with multiple comorbidities should be pointed out. Taking into account the inconsistent findings and the potential confounders and detection bias in previous epidemiological studies, it is expected that there are still more to be explored for the clarification of the association between diabetes and gastric cancer.

The role of the insulin-like growth factor-I receptor in malignancy: an update

In the past three decades, evidence has been accumulating that the IGF-I receptor/ligand system plays an important role in malignant disease. This has led to a search for specific inhibitors of the IGF receptor for cancer therapy, revealing some predictable, but also unexpected challenges. Here we review recent data that highlight the essential role of the IGF axis in several important steps in cancer cell progression and metastasis and highlight cellular processes that have been the focus of much interest and new insight in recent years. Strategies used to target the IGF axis clinically are summarized and the obstacles encountered are discussed.

Diabetes mellitus and risk of brain tumors: A meta-analysis

Accumulating evidence suggests that a history of diabetes may be involved in the occurrence of various types of cancer. However, the association of diabetes with the risk of brain tumors remains unclear. We identified relevant studies by performing a literature search of PubMed and EMBASE (through to 24 May 2012) and by searching the reference lists of pertinent articles. All data were extracted independently by two investigators using a standardized data abstraction tool. Summary relative risks (SRRs) with 95% confidence intervals (CIs) were calculated using a random-effects model. Inter-study heterogeneity was assessed using the Cochran’s Q and I² statistical tests. A total of 13 studies were included in this meta-analysis, including the entire Danish population, 5,107,506 other participants and more than 2,206 cases of brain tumors. In the analysis of these 13 studies, we observed that diabetic individuals had a similar risk of brain tumors as non-diabetic individuals (SRR, 1.12; 95% CI, 0.89–1.42). There was significant evidence of heterogeneity among these studies (P<0.001; I², 93.5%). Sub-group analysis revealed that diabetic females had a 24.2% increased risk of brain tumors (SRR, 1.242; 95% CI, 1.026–1.502), which was not observed in diabetic males. No significant publication bias was found in this study. The findings of this meta-analysis indicate that diabetic individuals have a similar risk of brain tumors as non-diabetic individuals. However, a significant positive correlation between the risk of brain tumors and diabetes mellitus was revealed in females, but not in males.

Clinical significance of immunohistochemical expression of insulin-like growth factor-1 receptor and matrix metalloproteinase-7 in resected non-small cell lung cancer

Insulin-like growth factor-1 receptor (IGF-1R) and matrix metalloproteinase-7 (MMP-7) have been reported to be related to tumor invasion and metastasis in various malignancies. The aim of this study was to evaluate the expression levels of IGF-1R and MMP-7 in resected non-small cell lung cancer (NSCLC) and to examine the relationship of such levels to clinical characteristics and survival. Expression was measured immunohistochemically. The percentage of stained cells was multiplied by the staining intensity. The sample was classified as high when the score was equal or higher than the median value or was otherwise considered to be low. High IGF-1R expression was associated with nodal metastasis and recurrence (P=0.034 and 0.006, respectively). High IGF-1R expression was associated with significantly poorer overall survival than low IGF-1R expression (P=0.011). MMP-7 expression did not significantly correlate with any clinicopathological factor. There was a trend toward slightly, but not significantly poorer survival in patients with MMP-7-high tumors than in those with MMP-7-low tumors (P=0.220). There was no significant correlation between IGF-1R expression and MMP-7 expression (P=0.184). Upon multivariate analysis, IGF-1R expression was independently related to the outcomes of patients with NSCLC. Overexpression of IGF-1R may be a useful predictor of lymph node metastasis, recurrence and post-surgical outcomes in patients with NSCLC.

Insulin-like growth factor receptor expression is associated with aggressive phenotypes and has therapeutic activity in biliary tract cancers

Insulin-like growth factor (IGF)-I receptor (IGF-IR) signaling is required for carcinogenicity and progression of several cancers but the function of this pathway and its utility as a therapeutic target have not been studied comprehensively in biliary tract carcinomas (BTC). We investigated the immunohistochemical expression of elements of the IGF axis, matrilysin, overexpression of p53 and the methylation status of the IGFBP-3 promoter in 80 surgically resected BTC. We also assessed the effect of IGF-IR blockade on signal transduction, proliferation and survival in three BTC cell lines using a new tyrosine kinase inhibitor, BMS-536924, and dominant negative IGF-IR (IGF-IR/dn). The effects of IGF-IR blockade was also studied in nude mouse xenograft models. IGF-I was expressed in 60% and IGF-II in 50% of tumors. High expression was associated with tumor size. IGF-IR was expressed in 69% of the cases and was associated with advanced stage and matrilysin expression. Hypermethylation of the IGFBP-3 promoter was detected in 41% of BTC and was inversely correlated with p53 expression. BMS-536924 blocked autophosphorylation of IGF-IR and both Akt and ERK activation by both IGF-I and insulin. BMS-536924 suppressed proliferation and tumorigenicity in vitro in a dose-dependent fashion. This inhibitor upregulated chemotherapy-induced apoptosis in a dose-dependent fashion. Moreover, IGF-IR blockade was effective against tumors in mice. IGF-IR might identify a subset of BTC with a particularly aggressive phenotype and is a candidate therapeutic target in this disease. BMS-536924 might have significant therapeutic utility.

Diabetes mellitus and risk of gastric cancer: a systematic review and meta-analysis of observational studies

AIM

Increasing evidence suggests that a history of diabetes may be involved in the development of various sites of cancer. However, the association of diabetes and risk of gastric cancer (GC) remains unclear.

METHODS

We identified studies by a literature search of MEDLINE (from 1 January 1966), Web of Science (from 1 January 1994), and EMBASE (from 1 January 1974 through 31 May 2011), and by searching the reference lists of pertinent articles. All data were extracted independently by two investigators using a standardized data abstraction tool. Summary relative risks (SRRs) with 95% confidence intervals (CIs) were calculated with a random-effects model. Between-study heterogeneity was assessed using the Cochran's Q and I statistics.

RESULTS

A total of 21 studies (four case-control studies, 17 cohort studies) were included in this meta-analysis. Analysis of these 21 studies found that compared with nondiabetic individuals, diabetic individuals had a similar risk of GC (SRRs, 1.09; 95% CI: 0.98-1.22). There was strong evidence of heterogeneity among these studies (P<0.001, I²=81.2%). A subgrouped analysis found that diabetic women had 18% increased risk of GC (SRRs, 1.18; 95% CI: 1.01-1.39), whereas it was not the case with diabetic men. No significant public bias was found in this study.

CONCLUSION

These findings of this systematic review indicate that compared with nondiabetic individuals, diabetic women have an 18% increased risk of GC development. However, diabetic men have a similar risk of GC.

The efficacy of IGF-I receptor monoclonal antibody against human gastrointestinal carcinomas is independent of k-ras mutation status

PURPOSE

Insulin-like growth factor (IGF)-I receptor (IGF-IR) signaling is required for carcinogenicity and proliferation of gastrointestinal cancers. We have previously shown successful targeting therapy for colorectal, pancreatic, gastric, and esophageal carcinomas using recombinant adenoviruses expressing dominant negative IGF-IR. Mutation in k-ras is one of key factors in gastrointestinal cancers. In this study, we sought to evaluate the effect of a new monoclonal antibody for IGF-IR, figitumumab (CP-751,871), on the progression of human gastrointestinal carcinomas with/without k-ras mutation.

EXPERIMENTAL DESIGN

We assessed the effect of figitumumab on signal transduction, proliferation, and survival in six gastrointestinal cancer cell lines with/without k-ras mutation, including colorectal and pancreatic adenocarcinoma, esophageal squamous cell carcinoma, and hepatoma. Combination effects of figitumumab and chemotherapy were also studied. Then figitumumab was evaluated in the treatment of xenografts in nude mice.

RESULTS

Figitumumab blocked autophosphorylation of IGF-IR and its downstream signals. The antibody suppressed proliferation and tumorigenicity in all cell lines. Figitumumab inhibited survival by itself and up-regulated chemotherapy (5-FU and gemcitabine) induced apoptosis. Moreover, the combination of this agent and chemotherapy was effective against tumors in mice. The effect of figitumumab was not influenced by the mutation status of k-ras. Figitumumab reduced expression of IGF-IR but not insulin receptor in these xenografted tumors. The drug did not affect murine body weight or blood concentrations of glucose, insulin, IGF binding protein 3, and growth hormone.

CONCLUSIONS

IGF-IR might be a good molecular therapeutic target and figitumumab may thus have therapeutic value in human gastrointestinal malignancies even in the presence of k-ras mutations.

Insulin-like growth factor-I receptor blockade reduces tumor angiogenesis and enhances the effects of bevacizumab for a human gastric cancer cell line, MKN45

BACKGROUND

Insulin-like growth factor (IGF)-I receptor (IGF-IR) signaling is required for tumorigenicity and tumor progression of gastrointestinal cancers. The authors previously reported the success of therapy for gastrointestinal cancers using adenoviruses that expressed dominant-negative IGF-IR (IGF-IR/dn). In addition, it has been demonstrated that IGF-IR signaling affects vascular endothelial growth factor (VEGF) expression in some other types of tumors. The objective of the current study was to evaluate this interaction by studying the roles of IGF-IR in tumor angiogenesis and lymphangiogenesis and their implications for targeted therapy in gastric cancer.

METHODS

The impact of IGF signals on the expression of VEGF-A and VEGF-C in a human gastric cancer cell, MKN45, and vascular formation were assessed. The effects of IGF-IR/dn with or without bevacizumab on angiogenesis, lymphangiogenesis, and tumor suppression in mouse xenografts were assessed.

RESULTS

IGFs induced the expression of VEGF ligands and up-regulated in vitro vascular vessel formation. IGF-IR/dn reduced VEGF expression, reduced the activation of both protein kinase B (Akt) and mitogen-activated protein kinase (MAPK), and reduced vascular formation, indicating that IGF-IR/dn inhibited tumor growth in mice by inhibiting both angiogenesis and lymphangiogenesis. However, IGF-IR/dn did not affect either blood sugar or body weight in these mice. The combination of IGF-IR/dn and bevacizumab was highly effective against these xenograft tumors, and only this combination resulted in the complete regression of 43% of tumors, reduced the expression of VEGF, and induced apoptosis.

CONCLUSIONS

The current results indicated that IGF-IR is involved in angiogenesis and lymphangiogenesis through the modulation of VEGF ligand expression in the gastric cancer cell line MKN45. Targeting IGF-IR in combination with agents that block the VEGF pathway may have therapeutic utility for gastric cancer therapy.

Molecular targeted approaches for treatment of pancreatic cancer

Human pancreatic cancer remains a highly malignant disease with almost similar incidence and mortality despite extensive research. Many targeted therapies are under development. However, clinical investigation showed that single targeted therapies and most combined therapies were not able to improve the prognosis of this disease, even though some of these therapies had excellent anti-tumor effects in pre-clinical models. Cross-talk between cell proliferation signaling pathways may be an important phenomenon in pancreatic cancer, which may result in cancer cell survival even though some pathways are blocked by targeted therapy. Pancreatic cancer may possess different characteristics and targets in different stages of pathogenesis, maintenance and metastasis. Sensitivity to therapy may also vary for cancer cells at different stages. The unique pancreatic cancer structure with abundant stroma creates a tumor microenvironment with hypoxia and low blood perfusion rate, which prevents drug delivery to cancer cells. In this review, the most commonly investigated targeted therapies in pancreatic cancer treatment are discussed. However, how to combine these targeted therapies and/or combine them with chemotherapy to improve the survival rate of pancreatic cancer is still a challenge. Genomic and proteomic studies using pancreatic cancer samples obtained from either biopsy or surgery are recommended to individualize tumor characters and to perform drug sensitivity study in order to design a tailored therapy with minimal side effects. These studies may help to further investigate tumor pathogenesis, maintenance and metastasis to create cellular expression profiles at different stages. Integration of the information obtained needs to be performed from multiple levels and dimensions in order to develop a successful targeted therapy.

A candidate targeting molecule of insulin-like growth factor-I receptor for gastrointestinal cancers

Advances in molecular research in cancer have brought new therapeutic strategies into clinical usage. One new group of targets is tyrosine kinase receptors, which can be treated by several strategies, including small molecule tyrosine kinase inhibitors (TKIs) and monoclonal antibodies (mAbs). Aberrant activation of growth factors/receptors and their signal pathways are required for malignant transformation and progression in gastrointestinal (GI) carcinomas. The concept of targeting specific carcinogenic receptors has been validated by successful clinical application of many new drugs. Type I insulin-like growth factor (IGF) receptor (IGF-IR) signaling potently stimulates tumor progression and cellular differentiation, and is a promising new molecular target in human malignancies. In this review, we focus on this promising therapeutic target, IGF-IR. The IGF/IGF-IR axis is an important modifier of tumor cell proliferation, survival, growth, and treatment sensitivity in many malignant diseases, including human GI cancers. Preclinical studies demonstrated that downregulation of IGF-IR signals reversed the neoplastic phenotype and sensitized cells to anticancer treatments. These results were mainly obtained through our strategy of adenoviruses expressing dominant negative IGF-IR (IGF-IR/dn) against gastrointestinal cancers, including esophagus, stomach, colon, and pancreas. We also summarize a variety of strategies to interrupt the IGFs/IGF-IR axis and their preclinical experiences. Several mAbs and TKIs targeting IGF-IR have entered clinical trials, and early results have suggested that these agents have generally acceptable safety profiles as single agents. We summarize the advantages and disadvantages of each strategy and discuss the merits/demerits of dual targeting of IGF-IR and other growth factor receptors, including Her2 and the insulin receptor, as well as other alternatives and possible drug combinations. Thus, IGF-IR might be a candidate for a molecular therapeutic target in human GI carcinomas.

Treatment of biliary tract cancer with NVP-AEW541: Mechanisms of action and resistance

AIM: To investigate in vitro treatment with NVP-AEW541, a small molecule inhibitor of insulin-like growth factor-1 receptor (IGF-1R), in biliary tract cancer (BTC), since this disease is associated with a poor prognosis due to wide resistance to chemotherapeutic agents and radiotherapy.

METHODS: Cell growth inhibition by NVP-AEW541 was studied in vitro in 7 human BTC cell lines by automated cell counting. In addition, the anti-tumoral mechanism of NVP-AEW541 was studied by Western blotting, cell cycle analysis and reverse transcription-polymerase chain reaction (RT-PCR). Anti-tumoral drug effect in combination with gemcitabine, 5-fluorouracil (5-FU) and Polo-like kinase 1 inhibitor BI2536 was also studied.

RESULTS: In vitro treatment with NVP-AEW541 suppressed growth in all human BTC cell lines, however response was lower in gallbladder cancer. Treatment with NVP-AEW541 was associated with dephosphorylation of IGF-1R and AKT. In contrast, phosphorylation of p42/p44 and Stat3 and expression of Bcl-xL were inconsistently downregulated. In addition, treated cells showed cell cycle arrest at the G1/S-checkpoint and an increase in sub-G1 peak. Moreover, IGF-1R and its ligands IGF-1 and IGF-2 were co-expressed in RT-PCR, suggesting an autocrine loop of tumor cell activation. Combined with gemcitabine, NVP-AEW541 exerted synergistic effects, particularly at low concentrations, while effects of combination with 5-FU or BI 2536 were only additive.

CONCLUSION: Our findings suggest that NVP-AEW541 is active against BTC in vitro and potentiates the efficacy of gemcitabine.