Cortactin Research Articles

Identification of potential biomarkers of peripheral blood mononuclear cell in hepatocellular carcinoma using bioinformatic analysis: A protocol for systematic review and meta-analysis.

Background:Hepatocellular carcinoma (HCC) is the cause of an overwhelming number of cancer-related deaths across the world. Developing precise and noninvasive biomarkers is critical for diagnosing HCC. Our research was designed to explore potentially useful biomarkers of host peripheral blood mononuclear cell (PBMC) in HCC by integrating comprehensive bioinformatic analysis.Methods:Gene expression data of PBMC in both healthy individuals and patients with HCC were extracted from the Gene Expression Omnibus (GEO) to identify differentially expressed genes (DEGs). The gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were applied to annotate the function of DEGs. Protein-protein interaction analysis was performed to screen the hub genes from DEGs. cBioportal database analysis was performed to assess the prognostic significance of hub genes. The Cancer Cell Line Encyclopedia (CCLE) and The Human Protein Atlas (HPA) database analyses were performed to confirm the expression levels of the hub genes in HCC cells and tissue.Results:A total of 95 DEGs were screened. Results of the GO analysis revealed that DEGs were primarily involved in platelet degranulation, cytoplasm, and protein binding. Results of the KEGG analysis indicated that DEGs were primarily enriched in focal adhesion. Five genes, namely, myosin light chain kinase (MYLK), interleukin 1 beta (IL1B), phospholipase D1 (PLD1), cortactin (CTTN), and moesin (MSN), were identified as hub genes. A search in the CCLE and HPA database showed that the expression levels of these hub genes were remarkably increased in the HCC samples. Survival analysis revealed that the overexpression of MYLK, IL1B, and PLD1 may have a significant effect on HCC survival. The aberrant high expression levels of MYLK, IL1B, and PLD1 strongly indicated worse prognosis in patients with HCC.Conclusions:The identified hub genes may be closely linked with HCC tumorigenicity and may act as potentially useful biomarkers for the prognostic prediction of HCC in PBMC samples.

PiR-19166 inhibits migration and metastasis through CTTN/MMPs pathway in prostate carcinoma.

Tumor metastasis is one of death causes for patients of prostate carcinoma. PIWI-interacting RNAs (piRNAs) are a subtype of noncoding protein RNAs that are involved in tumorigenesis, but the effect of piRNAs in prostate carcinoma (PCa) remains unclear. This article showed the identification of piRNAs was performed using a piRNA microarray screen in PCa tissues and several piRNAs were identified as dysregulated. The two up-regulated piRNAs (piR-19004 and piR-2878) and one down-regulated piR-19166 have been validated in the tissues and cell lines of PCa using quantitative reverse transcription polymerase chain reaction (qRT-PCR). Further studies showed that piR-19166 is transfected into PCa cells to suppress its migration and metastasis. Mechanistically, cortactin (CTTN) 3' untranslated region (UTR) was complementary combined with piR-19166 by bioinformatic prediction and identified as a direct target of piR-19166 through dual-luciferase reporter assay. Over-expression and knockdown of CTTN could respectively rescue and simulate the effects induced by piR-19166. Finally, piR-19166 suppresses migration and metastasis by the CTTN/matrix metalloproteinases (MMPs) pathway in PCa cells. Thus, these findings suggested that piR-19166 targets the CTTN of prostate cancer cells to inhibit migration and distant metastasis, and may represent a new marker of diagnosis and treatment for PCa patients in early stages.

RAC1-Dependent ORAI1 Translocation to the Leading Edge Supports Lamellipodia Formation and Directional Persistence

Tumor invasion requires efficient cell migration, which is achieved by the generation of persistent and polarized lamellipodia. The generation of lamellipodia is supported by actin dynamics at the leading edge where a complex of proteins known as the WAVE regulatory complex (WRC) promotes the required assembly of actin filaments to push the front of the cell ahead. By using an U2OS osteosarcoma cell line with high metastatic potential, proven by a xenotransplant in zebrafish larvae, we have studied the role of the plasma membrane Ca2+ channel ORAI1 in this process. We have found that epidermal growth factor (EGF) triggered an enrichment of ORAI1 at the leading edge, where colocalized with cortactin (CTTN) and other members of the WRC, such as CYFIP1 and ARP2/3. ORAI1-CTTN co-precipitation was sensitive to the inhibition of the small GTPase RAC1, an upstream activator of the WRC. RAC1 potentiated ORAI1 translocation to the leading edge, increasing the availability of surface ORAI1 and increasing the plasma membrane ruffling. The role of ORAI1 at the leading edge was studied in genetically engineered U2OS cells lacking ORAI1 expression that helped us to prove the key role of this Ca2+ channel on lamellipodia formation, lamellipodial persistence, and cell directness, which are required for tumor cell invasiveness in vivo.

Hypermethylation of UCHL1 Promotes Metastasis of Nasopharyngeal Carcinoma by Suppressing Degradation of Cortactin (CTTN).

Epigenetic regulation plays an important role in the development and progression of nasopharyngeal carcinoma (NPC), but the epigenetic mechanisms underlying NPC metastasis remain poorly understood. Here, we demonstrate that hypermethylation of the UCHL1 promoter leads to its downregulation in NPC. Restoration of UCHL1 inhibited the migration and invasion of NPC cells in vitro and in vivo, and knockdown of UCHL1 promoted NPC cell migration and invasion in vitro and in vivo. Importantly, we found that UCHL1 interacts with CTTN, and may function as a ligase promoting CTTN degradation by increasing K48-linked ubiquitination of CTTN. Additionally, restoration of CTTN in NPC cells that overexpressed UCHL1 rescued UCHL1 suppressive effects on NPC cell migration and invasion, which indicated that CTTN is a functional target of UCHL1 in NPC. Our findings revealed that UCHL1 acts as a tumor suppressor gene in NPC and thus provided a novel therapeutic target for NPC treatment.

SLC34A2 simultaneously promotes papillary thyroid carcinoma growth and invasion through distinct mechanisms.

Thyroid cancer is the fastest growing cancer among all solid tumors in recent decades. Papillary thyroid carcinoma (PTC) is the most predominant type of thyroid cancer. Around 30% of PTC patients with distant metastases and local invasion receive poor prognosis. Thus, the identification of new druggable biological targets is of great importance. Accumulating evidence indicates that solute carrier family numbers have emerged as obligate effectors during the progression of multiple malignancies. Here, we uncovered the functional significance, molecular mechanisms, and clinical impact of solute carrier family 34 member A2 (SLC34A2) in PTC. SLC34A2 was markedly overexpressed in PTC tissues at both mRNA and protein levels compared with matched adjacent normal tissues due to promoter hypomethylation mediated by the DNA methyltransferase 3 beta (DNMT3B). Furthermore, a series of in vivo and in vitro gain- or loss-of-functional assays elucidated the role of SLC34A2 in boosting cell proliferation, cell cycle progression, migration, invasion, and adhesion of PTC cells. Using immunoprecipitation and mass spectrometry, we discovered that SLC34A2 bound to the actin-binding repeats domain of Cortactin (CTTN), thereby inducing the invadopodia formation of PTC cells to promote the metastasis potential of PTC cells. Besides, our mechanistic studies, as well as gene set enrichment analysis (GSEA), have pinpointed the PTEN/AKT/FOXO3a pathway as a major signaling functioning downstream of SLC34A2 regulated cell growth. Taken together, our results highlighted that SLC34A2 plays a pivotal oncogenic role during carcinogenesis and metastasis through distinct mechanisms in PTC.

Bmal1-deficiency affects glial synaptic coverage of the hippocampal mossy fiber synapse and the actin cytoskeleton in astrocytes.

Bmal1 is an essential component of the molecular clockwork, which drives circadian rhythms in cell function. In Bmal1-deficient (Bmal1-/-) mice, chronodisruption is associated with cognitive deficits and progressive brain pathology including astrocytosis indicated by increased expression of glial fibrillary acidic protein (GFAP). However, relatively little is known about the impact of Bmal1-deficiency on astrocyte morphology prior to astrocytosis. Therefore, in this study we analysed astrocyte morphology in young (6-8 weeks old) adult Bmal1-/- mice. At this age, overall GFAP immunoreactivity was not increased in Bmal1-deficient mice. At the ultrastructural level, we found a decrease in the volume fraction of the fine astrocytic processes that cover the hippocampal mossy fiber synapse, suggesting an impairment of perisynaptic processes and their contribution to neurotransmission. For further analyses of actin cytoskeleton, which is essential for distal process formation, we used cultured Bmal1-/- astrocytes. Bmal1-/- astrocytes showed an impaired formation of actin stress fibers. Moreover, Bmal1-/- astrocytes showed reduced levels of the actin-binding protein cortactin (CTTN). Cttn promoter region contains an E-Box like element and chromatin immunoprecipitation revealed that Cttn is a potential Bmal1 target gene. In addition, the level of GTP-bound (active) Rho-GTPase (Rho-GTP) was reduced in Bmal1-/- astrocytes. In summary, our data demonstrate that Bmal1-deficiency affects morphology of the fine astrocyte processes prior to strong upregulation of GFAP, presumably because of impaired Cttn expression and reduced Rho-GTP activation. These morphological changes might result in altered synaptic function and, thereby, relate to cognitive deficits in chronodisruption.

The HBx\u2013CTTN interaction promotes cell proliferation and migration of hepatocellular carcinoma via CREB1

Hepatitis B virus-encoded X protein (HBx) acts as a tumor promoter during hepatocellular carcinoma (HCC) development, probably by regulating the expression of host proteins through protein–protein interaction. A proteomics approach was used to identify HBx-interacting proteins involved in HBx-induced hepatocarcinogenesis. We validated the proteomics findings by co-immunoprecipitation and confocal microscopy. We performed cell proliferation, migration assays and cell cycle analyses in HCC cells. Finally, we confirmed the clinical significance of our findings in samples from patients. We found that cortactin (CTTN) is a novel HBx-interacting protein, and HBx regulates the expression of CTTN in the HCC cell lines MHCC-LM3 and HepG2. Mechanistically, by upregulating the expression of cAMP response element-binding protein (CREB1) and its downstream targets, such as cyclin D1 and MMP-9, the effects of the HBx-CTTN interaction on the enhancement of cellular proliferation and migration were maintained by inhibiting cell cycle arrest. In addition, we demonstrated that the levels of CTTN and CREB1 were closely correlated in clinical samples from HBV-infected patients with HCC. Overall, our data suggests that HBx contributes to cell migration and proliferation of HCC cells by interacting with CTTN and regulating the expression of CTTN and CREB1. Therefore, the HBx/CTTN/CREB1 axis is a potential novel therapeutic target in HCC.

The Pathogenic Effect of Cortactin Tyrosine Phosphorylation in Cutaneous Squamous Cell Carcinoma.

Cortactin (CTTN) has been considered a promising molecular prognostic factor in various types of cancers. In this study, we aimed to investigate the role of CTTN in the pathogenesis of cutaneous squamous cell carcinoma (CSCC). CTTN and phospho-CTTN (p-CTTN) expression was determined in 10 healthy controls and 38 CSCC tissue samples by immunohistochemistry. The influence of CTTN on the biological behavior of CSCC cells was also investigated. p-CTTN expression was significantly increased in CSCC than control samples. In contrast, no significant difference in CTTN expression was found between control and CSCC tissues. Moreover, a significant association was found between recurrence-free survival with p-CTTN expression, but not with CTTN expression. Furthermore, the proliferative, migratory, and invasive abilities of CSCC cells were significantly decreased by CTTN-siRNA transfection. CTTN phosphorylation is strongly associated with CSCC pathogenesis and may serve as a molecular biomarker of CSCC.

Cortactin expression: Association with disease progression and survival in oral squamous cell carcinoma.

Cortactin (CTTN) is located on chromosome 11q13 and is associated with invasiveness in various cancer entities. CTTN protein expression could be a prognosticator of oral squamous cell carcinoma (OSCC) in terms of recurrence and survival. CTTN-dependent invasion was performed using migration assay in human papillomavirus-negative head and neck squamous cell carcinoma (HNSCC) cells. Cortactin protein analysis in tissue microarrays was used for correlation with clinical parameters, as well as for survival analysis. Gene expression profiling in HNSCC cells was performed to unreveal CTTN signaling. Knockdown of CTTN in HNSCC cells showed less invasion in vitro. Gene expression profiling showed various deregulated genes known to be involved in progression. We confirmed the link between CTTN overexpression and progression in a large clinical cohort. High expression was associated with worse overall and progression-free survival. We propose CTTN for managing OSCC in terms of adjuvant therapy and aftercare. Furthermore, our study reveals new potential targets in CTTN signaling for individualized OSCC therapy.

Effect of up-regulating the expression of microRNA-613 on biological behavior of human renal cell carcinoma cells

Objective To observe the effect of microRNA-613 (miR-613) on the biological behavior of human renal cell carcinoma cells and explore its molecular mechanism. Methods The synthesized miR-613 mimics and miR-NC were respectively transferred into 786-O cells by Lipofectamine 3000 and divided into experimental group and control group. Real time quantitative polymerase chain reaction (qPCR) was used to detect the expression of miR-613 in cells of two groups to verify the transfection success. The proliferation of 786-O cells was detected by methyl thiazolyl tetrazolium (MTT) assay and the migration of 786-O cells was detected by Transwell migration assay. Bioinformatics predicts the target gene of miR-613. Dual luciferase reporter assay validates the targeted relationship between miR-613 and target genes, and their binding sites. qPCR and Western blot were used to detect the expression of target genes. Results qPCR test results showed that the expression of miR-613 in the experimental group (16.22±1.08) was significantly higher than that in the control group (1.06±0.20), with statistically significant difference (P<0.01). The results of MTT showed that the cells in the experimental group showed a decrease in absorbance value at the d-th point after transfection (P<0.05). Transwell cell migration test results showed that the cells in the control group and experimental group migrated from the upper chamber of Transwell to the lower chamber of the cells were respectively (95.55±17.88) and (199.10±22.74), with statistically significant difference (P<0.05). Bioinformatics predicts that the target gene of miR-613 is Cortactin (CTTN). Dual luciferase reporter assay confirmed that miR-613 can target CTTN gene (P<0.05). miR-613 can significantly inhibit the CTTN gene expression in renal cell carcinoma cells (P<0.01). Conclusions Up-regulation of miR-613 expression can inhibit the proliferation and migration of renal cell carcinoma cells, and its possible molecular mechanism is that miR-613 inhibits the expression of CTTN gene. Key words: Carcinoma, renal cell/PP; MicroRNAs; Cell proliferation; Cell migration assays

Abstract 4420: MiR-182 suppresses invadopodia formation and metastasis in non-small cell lung cancer by targeting cortactin

Abstract Metastasis is the leading cause of cancer mortality and is a major hurdle for lung cancer treatment. Invadopodia, which are cancer-specific protrusive structures, play a crucial role in the metastatic cascade through degradation of the basement membrane and surrounding stroma, but the exact mechanism of regulation is not yet fully understood. In this study, we show that cortactin (CTTN), an important component of invadopodia, is upregulated in lung cancer tissues and is a marker of poorer prognosis in human NSCLC. Phorbol 12,13-dibutyrate and hepatocyte growth factor can induce CTTN expression and motility, as well as invadopodia formation in non-small cell lung cancer (NSCLC). MicroRNA-182 (miR-182) suppresses metastasis and invadopodia formation by targeting CTTN in NSCLC. qRT-PCR results showed that CTTN expression was inversely correlated with expression of miR-182. miR-182/CTTN suppresses invadopodia formation of lung cancer cells via suppression of the Cdc42/N-WASP pathway. Furthermore, miR-182 negatively regulates invadopodia function and suppresses extracellular matrix degradation in lung cancer cells by inhibiting CTTN. In conclusion, our results demonstrated that miR-182 targets CTTN in NSCLC and suppresses lung cancer invadopodia formation and thus suppresses lung cancer metastasis, suggesting a therapeutic application of miR-182 in NSCLC. Citation Format: Yongwen Li, Hongbing Zhang, Hongyu Liu, Jun Chen. MiR-182 suppresses invadopodia formation and metastasis in non-small cell lung cancer by targeting cortactin [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4420.

Immunohistochemical Expression of Cortactin and Focal Adhesion Kinase Predicts Recurrence Risk and Laryngeal Cancer Risk Beyond Histologic Grading.

Background: Cortactin (CTTN) and the focal adhesion kinase (FAK) are two major candidate genes to, respectively, drive 11q13- and 8q24-associated aggressive behavior in various cancers. Recent evidence uncovered their clinical relevance in early stages of tumorigenesis as promising biomarkers for cancer risk assessment.Methods: Using a multicenter validation study, CTTN and FAK expression was evaluated by immunohistochemistry (IHC) in a cohort of 109 patients with laryngeal precancerous lesions, and correlated with clinicopathologic parameters and laryngeal cancer risk. The pathophysiologic role of CTTN and FAK was further investigated using functional studies in cellular models.Results: Positive CTTN and FAK expression (scores 2 and 3) was detected in 49 (41%) and 35 (32%) laryngeal dysplasias, respectively. Univariate Cox analysis showed that CTTN and FAK expression but not histologic grading was significantly associated with both recurrence risk and laryngeal cancer risk. Patients carrying strong CTTN- or FAK-expressing lesions (score 3) experienced the highest laryngeal cancer incidence (log-rank P < 0.001). In multivariate stepwise analysis, FAK expression [HR = 13.91; 95% CI, 4.82-40.15; P < 0.001] and alcohol consumption (HR = 2.22; 95% confidence interval, 1.17-4.20; P = 0.014) were significant independent predictors of laryngeal cancer development. Targeting FAK by either RNAi or pharmacologic inhibitors effectively blocked cell growth, colony formation, and invasion into 3D collagen matrices.Conclusions: CTTN and FAK emerge as powerful predictors of laryngeal cancer risk and recurrence risk beyond histologic grading.Impact: Our work supports the applicability of IHC CTTN and FAK as complementary markers for risk stratification in patients with laryngeal precancerous lesions. Cancer Epidemiol Biomarkers Prev; 27(7); 805-13. ©2018 AACR.

Critical role of the HDAC6\u2013cortactin axis in human megakaryocyte maturation leading to a proplatelet-formation defect

Thrombocytopenia is a major side effect of a new class of anticancer agents that target histone deacetylase (HDAC). Their mechanism is poorly understood. Here, we show that HDAC6 inhibition and genetic knockdown lead to a strong decrease in human proplatelet formation (PPF). Unexpectedly, HDAC6 inhibition-induced tubulin hyperacetylation has no effect on PPF. The PPF decrease induced by HDAC6 inhibition is related to cortactin (CTTN) hyperacetylation associated with actin disorganization inducing important changes in the distribution of megakaryocyte (MK) organelles. CTTN silencing in human MKs phenocopies HDAC6 inactivation and knockdown leads to a strong PPF defect. This is rescued by forced expression of a deacetylated CTTN mimetic. Unexpectedly, unlike human-derived MKs, HDAC6 and CTTN are shown to be dispensable for mouse PPF in vitro and platelet production in vivo. Our results highlight an unexpected function of HDAC6–CTTN axis as a positive regulator of human but not mouse MK maturation.

Cortactin, a Lyn substrate, is a checkpoint molecule at the intersection of BCR and CXCR4 signalling pathway in chronic lymphocytic leukaemia cells.

Cortactin (CTTN) is a substrate of the Src kinase Lyn that is known to play an actin cytoskeletal regulatory role involved in cell migration and cancer progression following its phosphorylation at Y421. We recently demonstrated that Cortactin is overexpressed in patients with chronic lymphocytic leukaemia (CLL). This work was aimed at defining the functional role of Cortactin in these patients. We found that Cortactin is variably expressed in CLL patients both in the peripheral blood and lymph nodes and that its expression correlates with the release of matrix metalloproteinase 9 (MMP-9) and the motility of neoplastic cells. Cortactin knockdown, by siRNA, induced a reduction in MMP-9 release as well as a decrease of migration capability of leukaemic B cells invitro, also after chemotactic stimulus. Furthermore, Cortactin phosphorylation was lowered by the Src kinase-inhibitor PP2 with a consequent decrease of MMP-9 release in culture medium. An impaired migration, as compared to control experiments without Cortactin knockdown, was observed following CXCL12 triggering. Reduced Cortactin expression and phosphorylation were also detected both invivo and invitro after treatment with Ibrutinib, a Btk inhibitor. Our results highlight the role of Cortactin in CLL as a check-point molecule between the BCR and CXCR4 signalling pathways.

Regulation of membrane ruffling by polarized STIM1 and ORAI1 in cortactin-rich domains

Cell motility and migration requires the reorganization of the cortical cytoskeleton at the leading edge of cells and extracellular Ca2+ entry is essential for this reorganization. However the molecular nature of the regulators of this pathway is unknown. This work contributes to understanding the role of STIM1 and ORAI1 in the promotion of membrane ruffling by showing that phospho-STIM1 localizes at the leading edge of cells, and that both phospho-STIM1 and ORAI1 co-localize with cortactin (CTTN), a regulator of the cytoskeleton at membrane ruffling areas. STIM1-KO and ORAI1-KO cell lines were generated by CRISPR/Cas9 genome editing in U2OS cells. In both cases, KO cells presented a notable reduction of store-operated Ca2+ entry (SOCE) that was rescued by expression of STIM1-mCherry and ORAI1-mCherry. These results demonstrated that SOCE regulates membrane ruffling at the leading edge of cells. Moreover, endogenous ORAI1 and overexpressed ORAI1-GFP co-immunoprecipitated with endogenous CTTN. This latter result, in addition to the KO cells’ phenotype, the preservation of ORAI1-CTTN co-localization during ruffling, and the inhibition of membrane ruffling by the Ca2+-channel inhibitor SKF96365, further supports a functional link between SOCE and membrane ruffling.

Role of CD44 and cortactin in metastasis of oral squamous cell carcinoma

Context: Oral squamous cell carcinoma (OSCC) is the most common form of head and neck cancer, and over the last decade its incidence has increased by 50%. The tendency of OSCC for local and regional metastasis is high and this is thought to be the greatest contributor to the morbidity and mortality associated with OSCC. Aim: The aim of this study was directed to evaluate the role of both cluster of differentiation 44 (CD44) and cortactin (CTTN) in lymph node (LN) metastasis of OSCC. Materials and methods: The study groups comprised blocks of OSCC with LN metastasis (n = 20) and blocks of OSCC without LN metastasis (n = 20). The blocks were prepared for immunohistochemical staining for CD44 and CTTN. Results: The result of this study revealed significant correlation between expression of both CD44 and CTTN and LN metastasis. Conclusion: From the present study, it can be concluded that assessment of CD44 and CTTN in OSCC represent an important tool for prediction of risk of metastasis for each case and the significant correlation between CD44 and CTTN could provide insights of their critical role in metastasis.

Cortactin promotes colorectal cancer cell proliferation by activating the EGFR-MAPK pathway.

Cortactin (CTTN) is overexpressed in various tumors, including head and neck squamous cell carcinoma and colorectal cancer (CRC), and can serve as a biomarker of cancer metastasis. We observed that CTTN promotes cancer cell proliferation in vitro and increases CRC tumor xenograft growth in vivo. CTTN expression increases EGFR protein levels and enhances the activation of the MAPK signaling pathway. CTTN expression also inhibits the ubiquitin-mediated degradation of EGFR by suppressing the coupling of c-Cbl with EGFR. CoIP experiments indicate CTTN can interact with c-Cbl in CRC cells. These results demonstrate that CTTN promotes the proliferation of CRC cells and suppresses the degradation of EGFR.

Pro-invasive Effect of Proto-oncogene PBF Is Modulated by an Interaction with Cortactin.

Context:Metastatic disease is responsible for the majority of endocrine cancer deaths. New therapeutic targets are urgently needed to improve patient survival rates.Objective:The proto-oncogene PTTG1-binding factor (PBF/PTTG1IP) is overexpressed in multiple endocrine cancers and circumstantially associated with tumor aggressiveness. This study aimed to understand the role of PBF in tumor cell invasion and identify possible routes to inhibit its action.Design, Setting, Patients, and Interventions:Thyroid, breast, and colorectal cells were transfected with PBF and cultured for in vitro analysis. PBF and cortactin (CTTN) expression was determined in differentiated thyroid cancer and The Cancer Genome Atlas RNA-seq data.Primary Outcome Measure:Pro-invasive effects of PBF were evaluated by 2D Boyden chamber, 3D organotypic, and proximity ligation assays.Results:Our study identified that PBF and CTTN physically interact and co-localize, and that this occurs at the cell periphery, particularly at the leading edge of migrating cancer cells. Critically, PBF induces potent cellular invasion and migration in thyroid and breast cancer cells, which is entirely abrogated in the absence of CTTN. Importantly, we found that CTTN is over-expressed in differentiated thyroid cancer, particularly in patients with regional lymph node metastasis, which significantly correlates with elevated PBF expression. Mutation of PBF (Y174A) or pharmacological intervention modulates the PBF: CTTN interaction and attenuates the invasive properties of cancer cells.Conclusion:Our results demonstrate a unique role for PBF in regulating CTTN function to promote endocrine cell invasion and migration, as well as identify a new targetable interaction to block tumor cell movement.

Cortactin promotes cell migration and invasion through upregulation of the dedicator of cytokinesis1 expression in human colorectal cancer.

Cortactin (CTTN), a major substrate of the Src tyrosine kinase, has been implicated in cell proliferation, motility and invasion in various types of cancer. However, the molecular mechanisms of CTTN-driven malignant behavior remain unclear. In the current study, we determined the expression of CTTN in colorectal cancer and investigated its underlying mechanism in the metastasis of colorectal cancer. We confirmed increased CTTN expression in lymph node-positive CRC specimens and highly invasive CRC cell lines. Further study has shown that overexpression of CTTN promoted CRC cell migration and invasion, whereas CTTN silencing inhibited CRC cell migratory and invasive capacities invitro. Mechanistically, CTTN increases expression of dedicator of cytokinesis1 (DOCK1) and gene silencing of DOCK1 partially abolishes the migration and invasion capacity by CTTN. Our findings indicate that CTTN promotes metastasis of CRC cells by increasing DOCK1 expression and this could offer a promising therapeutic target for colorectal cancer treatment.

Abstract 5064: CORO1B amplification and expression status identifies an aggressive subset of chromosome 11q13 amplified HNSCC

Abstract Head and neck squamous cell carcinoma (HNSCC) is highly invasive cancer type that occurs with greater incidence in West Virginia and the rest of Appalachia. The chromosome 11q13 region is amplified in approximately 30% of late stage HNSCC cases and is associated with a poor patient prognosis. The core 11q13 region encodes the well-studied tumor genes CCND1 (cyclin D1) and CTTN (cortactin). The CORO1B (coronin 1B) gene flanks the 11q13 core and is amplified in 9-14% of all HNSCC, but how CORO1B amplification contributes to HNSCC is unknown. Coronin 1B governs cell motility by negatively regulating F-actin stability through displacement of cortactin at actin related protein 2/3 (Arp 2/3) branch points, generating dynamic turnover of Arp2/3-F-actin networks required for productive cell movement. Kaplan-Meier analysis of two independent patient cohorts indicates that HNSCC cases with CORO1B amplification have significantly reduced overall survival. Cox hazard ratios also indicate the CORO1B amplification is strongly associated with increased mortality in both cohorts. Automated quantitative analysis (AQUA) of coronin 1B expression in HNSCC tissue microarrays indicates that coronin 1B overexpression decreases median survival of HNSCC patients from 81 to 29 months. Reduced expression of coronin 1B by RNAi-mediated knockdown in established HNSCC cell lines decreases several actin-mediated invasive processes, including invadopodia formation and extracelluar matrix degradation. Collectively these results suggest that elevated coronin 1B expression levels in HNSCC function to enhance tumor invasion, potentially through accelerated downregulation of cortactin stabilizing activity at Arp2/3-F-actin junctions. Importantly, CORO1B amplification and coronin 1B expression status may serve a role as a precision biomarker for identification of a subset of late-stage HNSCC patients that would benefit from more aggressive forms of initial clinical treatment. Citation Format: Jessica L. Allen, Elyse L. Walk, Kristen L. Rhodes, Colleen J. Beatty, Steven M. Markwell, Brenen W. Papenberg, Erik T. Interval, Hong Wu, Marileila Varella Garcia, James E. Bear, Scott A. Weed. CORO1B amplification and expression status identifies an aggressive subset of chromosome 11q13 amplified HNSCC. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5064.