ABSTRACT
Breast cancer is the most common cancer in women worldwide, and advanced breast cancer is the leading cause of cancer death in women. In present study, we aim to investigate that role of T-cell lymphoma invasion and metastasis-inducing protein1 (TIAM1) on NVP-BEZ235 resistance to breast cancer MCF7 and MDA-MB-361 cells. Briefly, MCF7 and MDA-MB-361 cells were treated with NVP-BEZ235 and the relative expressions of TIAM1 at both mRNA level and protein level were determined by RT-PCR and western blot. In addition, MCF7 and MDA-MB-361 cells were transfected with TIAM1 knockdown or overexpression vector. Then the IC50 of NVP-BEZ235 on MCF7 and MDA-MB-361 cells were detected by MTT assay. Finally, FGFR/STAT3 pathway protein members were investigated by western blot. Consequently, we found that the mRNA and protein expressions of TIAM1 and FGFR1/3 were dramatically upregulated in NVP-BEZ235-treated group in both MCF7 and MDA-MB-361 cells. Interestingly, TIAM1 knockdown via shRNA decreased the IC50 of NVP-BEZ235 of breast cancer cells, while TIAM1 overexpression increased the IC50 of NVP-BEZ235 of breast cancer cells, which suggested that TIAM1 was one of the contributors for NVP-BEZ235 resistance. In addition, FGFR members including FGFR1/3 showed similar results to TIAM1. Importantly, FGFR inhibitor AZD4547 decreased the IC50 of NVP-BEZ235, which suggested that FGFR downregulation reduced the NVP-BEZ235 resistance to breast cancer cells. In summary, our present study revealed that TIAM1 conferred NVP-BEZ235 resistance to breast cancer cells via activating FGFR/STAT3 pathway.
Subject(s)
Breast Neoplasms/metabolism , Drug Resistance, Neoplasm , Gene Expression Regulation, Neoplastic , Imidazoles/pharmacology , Neoplasm Proteins/biosynthesis , Quinolines/pharmacology , Receptor, Fibroblast Growth Factor, Type 1/metabolism , Receptor, Fibroblast Growth Factor, Type 3/metabolism , STAT3 Transcription Factor/metabolism , T-Lymphoma Invasion and Metastasis-inducing Protein 1/biosynthesis , Up-Regulation , Female , Humans , MCF-7 Cells , Neoplasm Proteins/genetics , Receptor, Fibroblast Growth Factor, Type 1/genetics , Receptor, Fibroblast Growth Factor, Type 3/genetics , STAT3 Transcription Factor/genetics , T-Lymphoma Invasion and Metastasis-inducing Protein 1/geneticsABSTRACT
Skeletal muscle is constantly renewed in response to injury, exercise, or muscle diseases. Muscle stem cells, also known as satellite cells, are stimulated by local damage to proliferate extensively and form myoblasts that then migrate, differentiate, and fuse to form muscle fibers. The transmembrane heparan sulfate proteoglycan syndecan-4 plays multiple roles in signal transduction processes, such as regulating the activity of the small GTPase Rac1 (Ras-related C3 botulinum toxin substrate 1) by binding and inhibiting the activity of Tiam1 (T-lymphoma invasion and metastasis-1), a guanine nucleotide exchange factor for Rac1. The Rac1-mediated actin remodeling is required for cell migration. Syndecan-4 knockout mice cannot regenerate injured muscle; however, the detailed underlying mechanism is unknown. Here, we demonstrate that shRNA-mediated knockdown of syndecan-4 decreases the random migration of mouse myoblasts during live-cell microscopy. Treatment with the Rac1 inhibitor NSC23766 did not restore the migration capacity of syndecan-4 silenced cells; in fact, it was further reduced. Syndecan-4 knockdown decreased the directional persistence of migration, abrogated the polarized, asymmetric distribution of Tiam1, and reduced the total Tiam1 level of the cells. Syndecan-4 affects myoblast migration via its role in expression and localization of Tiam1; this finding may facilitate greater understanding of the essential role of syndecan-4 in the development and regeneration of skeletal muscle.
Subject(s)
Cell Movement , Gene Expression Regulation , Myoblasts/metabolism , Syndecan-4/metabolism , T-Lymphoma Invasion and Metastasis-inducing Protein 1/biosynthesis , Animals , Cell Line , Gene Knockdown Techniques , Mice , Myoblasts/cytology , Syndecan-4/genetics , T-Lymphoma Invasion and Metastasis-inducing Protein 1/geneticsABSTRACT
T lymphoma invasion and metastasis 1 (Tiam1), a guanine nucleotide exchange factor, is involved in the tumorigenesis of a number of malignancies. This study was aimed to explore the role of Tiam1 in cervical cancer progression, and evaluate the prognostic values. Tiam1 protein expression levels were detected by immunohistochemical (IHC) staining in 174 cervical cancer tissues, 92 of CINs (cervical intraepithelial neoplasia) and 32 of normal cervical epithelia tissues. Clinicopathological parameters and overall survival data were collected and compared between different Tiam1 statuses. The role of Tiam1 in cervical cancer proliferation, migration and angiogenesis were detected using si-RNA (small interfering RNA) transfection. In results, Tiam1 protein showed a cytoplasmic and nuclear staining pattern in cervical cancer tissues. The strongly positive expression of Tiam1 protein was observed in 51.72% (90/174) of cervical cancers, which was significantly higher than in CINs and normal cervical epithelia tissues (9.38%, 3/32). High Tiam1 protein expression was closely associated with advanced clinical stage, differentiation, lymph node (LN) metastasis, HPV infection and lower overall survival (OS) rates in cervical cancer. Multivariate analysis indicated that Tiam1 was an independent prognostic factor, along with clinical stage, in patients with cervical cancer. Additionally, Tiam1 depletion by RNAi in cervical cancer cells significantly decreased cell proliferation, migration and angiogenesis. In conclusion, our study demonstrated that upregulation of Tiam1 contributes to cervical cancer disease progression and indicates poor survival outcome.
