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Concomitant targeting of EGF receptor, TGF-beta and SRC points to a novel therapeutic approach in pancreatic cancer.

ABSTRACT: To test the hypothesis that concomitant targeting of the epidermal growth factor receptor (EGFR) and transforming growth factor-beta (TGF-?) may offer a novel therapeutic approach in pancreatic cancer, EGFR silencing by RNA interference (shEGFR) was combined with TGF-? sequestration by soluble TGF-? receptor II (sT?RII). Effects on colony formation in 3-dimensional culture, tumor formation in nude mice, and downstream signaling were monitored. In both ASPC-1 and T3M4 cells, either shEGFR or sT?RII significantly inhibited colony formation. However, in ASPC-1 cells, combining shEGFR with sT?RII reduced colony formation more efficiently than either approach alone, whereas in T3M4 cells, shEGFR-mediated inhibition of colony formation was reversed by sT?RII. Similarly, in vivo growth of ASPC-1-derived tumors was attenuated by either shEGFR or sT?RII, and was markedly suppressed by both vectors. By contrast, T3M4-derived tumors either failed to form or were very small when EGFR alone was silenced, and these effects were reversed by sT?RII due to increased cancer cell proliferation. The combination of shEGFR and sT?RII decreased phospho-HER2, phospho-HER3, phoshpo-ERK and phospho-src (Tyr416) levels in ASPC-1 cells but increased their levels in T3M4 cells. Moreover, inhibition of both EGFR and HER2 by lapatinib or of src by SSKI-606, PP2, or dasatinib, blocked the sT?RII-mediated antagonism of colony formation in T3M4 cells. Together, these observations suggest that concomitantly targeting EGFR, TGF-?, and src may constitute a novel therapeutic approach in PDAC that prevents deleterious cross-talk between EGFR family members and TGF-?-dependent pathways.

SUBMITTER: Deharvengt S

PROVIDER: S-EPMC3384603 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature

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Concomitant targeting of EGF receptor, TGF-beta and SRC points to a novel therapeutic approach in pancreatic cancer.

Deharvengt Sophie S Marmarelis Melina M Korc Murray M

PloS one 20120627 6

To test the hypothesis that concomitant targeting of the epidermal growth factor receptor (EGFR) and transforming growth factor-beta (TGF-β) may offer a novel therapeutic approach in pancreatic cancer, EGFR silencing by RNA interference (shEGFR) was combined with TGF-β sequestration by soluble TGF-β receptor II (sTβRII). Effects on colony formation in 3-dimensional culture, tumor formation in nude mice, and downstream signaling were monitored. In both ASPC-1 and T3M4 cells, either shEGFR or sTβR ...[more]

PMID: 22761868

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Project description:Increased microRNA-10b (miR-10b) expression in the cancer cells in pancreatic ductal adenocarcinoma (PDAC) is a marker of disease aggressiveness. In the present study, we determined that plasma miR-10b levels are significantly increased in PDAC patients by comparison with normal controls. By gene profiling, we identified potential targets downregulated by miR-10b, including Tat-interacting protein 30 (TIP30). Immunoblotting and luciferase reporter assays confirmed that TIP30 was a direct miR-10b target. Downregulation of TIP30 by miR-10b or siRNA-mediated silencing of TIP30 enhanced epidermal growth factor (EGF)-dependent invasion. The actions of miR-10b were abrogated by expressing a modified TIP30 cDNA resistant to miR-10b. EGF-induced EGF receptor (EGFR) tyrosine phosphorylation and extracellular signal-regulated kinase phosphorylation were enhanced by miR-10b, and these effects were mimicked by TIP30 silencing. The actions of EGF in the presence of miR-10b were blocked by EGFR kinase inhibition with erlotinib and by dual inhibition of PI3K (phosphatidylinositol 3'-kinase) and MEK. Moreover, miR-10b, EGF and transforming growth factor-beta (TGF-β) combined to markedly increase cell invasion, and this effect was blocked by the combination of erlotinib and SB505124, a type I TGF-β receptor inhibitor. miR-10b also enhanced the stimulatory effects of EGF and TGF-β on cell migration and epithelial-mesenchymal transition (EMT) and decreased the expression of RAP2A, EPHB2, KLF4 and NF1. Moreover, miR-10b overexpression accelerated pancreatic cancer cell (PCC) proliferation and tumor growth in an orthotopic model. Thus, plasma miR-10b levels may serve as a diagnostic marker in PDAC, whereas intra-tumoral miR-10b promotes PCC proliferation and invasion by suppressing TIP30, which enhances EGFR signaling, facilitates EGF-TGF-β cross-talk and enhances the expression of EMT-promoting genes, whereas decreasing the expression of several metastasis-suppressing genes. Therefore, therapeutic targeting of miR-10b in PDAC may interrupt growth-promoting deleterious EGF-TGF-β interactions and antagonize the metastatic process at various levels.

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Concomitant targeting of EGF receptor, TGF-beta and SRC points to a novel therapeutic approach in pancreatic cancer.

Publications

Concomitant targeting of EGF receptor, TGF-beta and SRC points to a novel therapeutic approach in pancreatic cancer.

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