Project description:Cancer-associated fibroblasts (CAFs) are an integral part of the tumor microenvironment often linked to drug resistance. Here, we report that CAFs, but not normal fibroblasts, can promote either resistance or unexpected drug sensitization of different lung cancer cells. Using unbiased secretomics, transcriptomics and tyrosine phosphoproteomics, we observed differential expression of several IGF1R signaling components, such as IGF-binding proteins and IGF1/2, and downstream signaling effects on cancer cells by fibroblasts. IGF1/2 treatment or IGFBP5 silencing in CAFs reversed, while addition of exogenous IGFBPs or pharmacological IGF1R inhibitors phenocopied the sensitizing effects. Combining IGF1R and EGFR inhibitors synergized in 2D and 3D models of different drug-resistant and naïve EGFR-mutant lung cancer cells and decreased tumor growth in vivo. These results suggest that multiple resistance mechanisms coexist within the same cancer cells, that CAFs context-dependently cause drug resistance or sensitization, and that understanding both of these differential mechanisms leads to improved therapeutic approaches.
Project description:Cancer-associated fibroblasts (CAFs) are an integral part of the tumor microenvironment often linked to drug resistance. Here, we report that CAFs, but not normal fibroblasts, can promote either resistance or unexpected drug sensitization of different lung cancer cells. Using unbiased secretomics, transcriptomics and tyrosine phosphoproteomics, we observed differential expression of several IGF1R signaling components, such as IGF-binding proteins and IGF1/2, and downstream signaling effects on cancer cells by fibroblasts. IGF1/2 treatment or IGFBP5 silencing in CAFs reversed, while addition of exogenous IGFBPs or pharmacological IGF1R inhibitors phenocopied the sensitizing effects. Combining IGF1R and EGFR inhibitors synergized in 2D and 3D models of different drug-resistant and naïve EGFR-mutant lung cancer cells and decreased tumor growth in vivo. These results suggest that multiple resistance mechanisms coexist within the same cancer cells, that CAFs context-dependently cause drug resistance or sensitization, and that understanding both of these differential mechanisms leads to improved therapeutic approaches.
Project description:Regeneration of lung epithelium is vital for maintaining airway function and integrity. An imbalance between epithelial damage and repair is at the basis of numerous chronic lung diseases such as asthma, COPD, pulmonary fibrosis and lung cancer. IGF (Insulin-like Growth Factors) signaling has been associated with most of these respiratory pathologies, although their mechanisms of action in this tissue remain poorly understood. Expression profiles analyses of IGF system genes performed in mouse lung support their functional implication in pulmonary ontogeny. Immuno-localization revealed high expression levels of Igf1r (Insulin-like Growth Factor 1 Receptor) in lung epithelial cells, alveolar macrophages and smooth muscle. To further understand the role of Igf1r in pulmonary homeostasis, two distinct lung epithelial-specific Igf1r mutant mice were generated and studied. The lack of Igf1r disturbed airway epithelial differentiation in adult mice revealed enhanced proliferation and altered morphology in distal airway club cells. During recovery after naphthalene-induced club cell injury, the kinetics of terminal bronchiolar epithelium regeneration was hindered in Igf1r mutants, revealing increased proliferation and delayed differentiation of club and ciliated cells. Amid airway restoration, lungs of Igf1r deficient mice showed increased levels of Igf1, Insr, Igfbp3 and epithelial precursor markers, reduced amounts of Scgb1a1 protein, and alterations in IGF signaling mediators. These results support the role of Igf1r in controlling the kinetics of cell proliferation and differentiation during pulmonary airway epithelial regeneration after injury.
Project description:The insulin-like growth factor (IGF) axis is an important signaling pathway in the growth and survival of many cell types and has been implicated in multiple aspects of cancer progression from tumorigenesis to metastasis. The multiple roles of IGF signaling in cancer suggest that selective inhibition of the pathway might yield clinically effective therapeutics. Here we describe A-928605, a novel small molecule inhibitor of the receptor tyrosine kinase responsible for IGF signal transduction. This small molecule is able to abrogate activation of the pathway as shown by effects on the target and downstream effectors and is shown to be effective at inhibiting the proliferation of an oncogene addicted tumor model cell line (CD8-IGF1R 3T3) both in vitro and in vivo. Experiment Overall Design: CD8-IGF1R 3T3 cells and 3T3 Vector control treated for 24 h with vehicle or IGF1R inhibitor A-928605, all with 3 replicates.
Project description:The insulin/IGF system plays a central role in regulating metabolism and growth. We identified viral insulin/IGF1-like peptides (VILPs) in Iridoviridae and investigated their role in host-virus interactions. Using Grouper Iridovirus (GIV) on grouper and zebrafish cells, we show that VILPs are early viral genes and are secreted during infection. VILPs activate insulin receptor (IR) and IGF-1 receptor (IGF1R) phosphorylation and stimulate the PI3K pathway. Supernatants from infected cells trigger dose and time-dependent signaling with GIV-VILP selectively interacts with IGF1R. Functionally, IR inhibition suppresses GIV replication, whereas IGF1R inhibition enhances it, and IGF-1 stimulation reduces replication. During infection, GIV-VILP competes with IGF-1, attenuating IGF1R signaling and reducing proliferation. Transcriptome analysis confirms negative regulation of cell cycle pathways. Using a zebrafish infection model, we demonstrate VILP expression and IGF-1 signaling inhibition. Our findings reveal a viral mimicry mechanism that modulates host IGF-1 signaling to promote viral replication.
Project description:The important role of IGF-1R in cancers has been well established. Classical model involves IGF-1/2 binding to IGF-1R, following activation of the PI3K/Akt pathway, thereby promoting cell proliferation, apoptosis inhibition and treatment resistance. While IGF-1R has become a promising target for cancer therapy, clinical disclosures subsequently have been less encouraging. The question is whether targeting IGF/IGF-1R still holds therapeutic potential. Here we show a novel mechanism that knockdown IGF-1R surprisingly triggers cytoplasmic viral RNA sensors MDA5 and RIG-1, leading to mitochondrial apoptosis in cancer. We analyzed MDA5 and RIG-1 in the intestinal epithelium of IGF-1R knockdown mice. Igf1r+/- mice demonstrated higher MDA5 and RIG-1 than WT mice. IGF-1R knockdown-triggered MDA5 and RIG-1 was further analyzed in human cancer and normal cells. Increased MDA5 and RIG-1 were clearly seen in the cytoplasm identified by immunofluoresce in the cells silenced IGF-1R. Block off IGF-1R downstream PI3K/Akt did not impact on MDA5 and RIG-1 expression. IGF-1R knockdown-triggered MDA5 and RIG-1 and their signaling pathways were similar to those of viral RNA mimetic poly(I:C) had. IGF-1R knockdown-triggered MDA5 and RIG-1 led to cancer apoptosis through activation of the mitochondrial pathway. In vivo assay, Igf1r+/- mice strongly resisted AOM-induced colonic tumorigenesis through triggering MDA¬5- and RIG-1-mediated apoptosis. Notably, RIG-I and MDA5-mediated proapoptotic signaling pathway is preferential active in cancer cells. These data suggest that targeting IGF-1R-triggered MDA5 and RIG-1 might have therapeutic potential for cancer treatment.
Project description:Ovarian cancer can metastasize to the omentum, which is associated with a complex tumor microenvironment. Omental stromal cells facilitate ovarian cancer colonization by secreting cytokines and growth factors. Improved understanding of the tumor supportive functions of specific cell populations in the omentum could identify strategies to prevent and treat ovarian cancer metastasis. Here, we showed that omental preadipocytes enhance the tumor initiation capacity of ovarian cancer cells. Secreted factors from preadipocytes supported cancer cell viability during nutrient and isolation stress and enabled prolonged proliferation. Co-culturing with pre-adipocytes led to upregulation of genes involved in extracellular matrix (ECM) organization, cellular response to stress, and regulation of insulin-like growth factor (IGF) signaling in ovarian cancer cells. IGF-1 induced ECM genes and increased alternative NF-κB signaling by activating RelB. Inhibiting the IGF-1 receptor (IGF1R) initially increased tumor omental adhesion but decreased growth of established preadipocyte-induced subcutaneous tumors as well as established intraperitoneal tumors. Together, this study shows that omental preadipocytes support ovarian cancer progression, which has implications for targeting metastasis.
Project description:Adult tissue stem cells are known to participate in cancer formation. Indeed, cells exhibiting markers of embryonic stem cells such as Oct-4 and Nanog were detected in some malignant tumors. In this study we demonstrated that stromal cells prepared from the basal cell carcinoma are able to induce expression of embryonic stem cell markers such as the Oct-4, Nanog and Sox-2 in mouse 3T3 fibroblasts. These stem cell-like elements have the differentiation potential similar to mesenchymal stem cells. They are also able to induce expression of Oct-4 and Nanog in the human hair follicle keratinocytes. Employing the microarray technology, the role of growth factors such as IGF-2, FGF-7, leptin, NGF and TGF-_ produced by stromal fibroblasts was established to be responsible for the biological activity of the fibroblasts.
Project description:The insulin-like growth factor (IGF) axis is an important signaling pathway in the growth and survival of many cell types and has been implicated in multiple aspects of cancer progression from tumorigenesis to metastasis. The multiple roles of IGF signaling in cancer suggest that selective inhibition of the pathway might yield clinically effective therapeutics. Here we describe A-928605, a novel small molecule inhibitor of the receptor tyrosine kinase responsible for IGF signal transduction. This small molecule is able to abrogate activation of the pathway as shown by effects on the target and downstream effectors and is shown to be effective at inhibiting the proliferation of an oncogene addicted tumor model cell line (CD8-IGF1R 3T3) both in vitro and in vivo. Keywords: Treatment Response