Varvara K. Kozyreva

NEDD9 Regulates Actin Dynamics through Cortactin Deacetylation in an AURKA/HDAC6–Dependent Manner

The prometastatic protein NEDD9 (neural precursor cell expressed, developmentally downregulated 9) is highly expressed in many cancers and is required for mesenchymal individual cell migration and progression to the invasive stage. Nevertheless, the molecular mechanisms of NEDD9-driven migration and the downstream targets effecting metastasis are not well defined. In the current study, knockdown of NEDD9 in highly metastatic tumor cells drastically reduces their migratory capacity due to disruption of actin dynamics at the leading edge. Specifically, NEDD9 deficiency leads to a decrease in the persistence and stability of lamellipodial protrusions similar to knockdown of cortactin (CTTN). Mechanistically, it was shown that NEDD9 binds to and regulates acetylation of CTTN in an Aurora A kinase (AURKA)/HDAC6–dependent manner. The knockdown of NEDD9 or AURKA results in an increase in the amount of acetylated CTTN and a decrease in the binding of CTTN to F-actin. Overexpression of the deacetylation mimicking (9KR) mutant of CTTN is sufficient to restore actin dynamics at the leading edge and migration proficiency of the tumor cells. Inhibition of AURKA and HDAC6 activity by alisertib and Tubastatin A in xenograft models of breast cancer leads to a decrease in the number of pulmonary metastases. Collectively, these findings identify CTTN as the key downstream component of NEDD9-driven migration and metastatic phenotypes. Implications: This study provides a mechanistic platform for therapeutic interventions based on AURKA and HDAC6 inhibition for patients with metastatic breast cancer to prevent and/or eradicate metastases. Mol Cancer Res; 12(5); 681–93. ©2014 AACR.

NEDD9 Depletion Leads to MMP14 Inactivation by TIMP2 and Prevents Invasion and Metastasis.

The scaffolding protein NEDD9 is an established prometastatic marker in several cancers. Nevertheless, the molecular mechanisms of NEDD9-driven metastasis in cancers remain ill-defined. Here, using a comprehensive breast cancer tissue microarray, it was shown that increased levels of NEDD9 protein significantly correlated with the transition from carcinoma in situ to invasive carcinoma. Similarly, it was shown that NEDD9 overexpression is a hallmark of highly invasive breast cancer cells. Moreover, NEDD9 expression is crucial for the protease-dependent mesenchymal invasion of cancer cells at the primary site but not at the metastatic site. Depletion of NEDD9 is sufficient to suppress invasion of tumor cells in vitro and in vivo, leading to decreased circulating tumor cells and lung metastases in xenograft models. Mechanistically, NEDD9 localized to invasive pseudopods and was required for local matrix degradation. Depletion of NEDD9 impaired invasion of cancer cells through inactivation of membrane-bound matrix metalloproteinase MMP14 by excess TIMP2 on the cell surface. Inactivation of MMP14 is accompanied by reduced collagenolytic activity of soluble metalloproteinases MMP2 and MMP9. Reexpression of NEDD9 is sufficient to restore the activity of MMP14 and the invasive properties of breast cancer cells in vitro and in vivo. Collectively, these findings uncover critical steps in NEDD9-dependent invasion of breast cancer cells. Implications: This study provides a mechanistic basis for potential therapeutic interventions to prevent metastasis. Mol Cancer Res; 12(1); 69–81. ©2013 AACR.

NEDD9/Arf6-dependent endocytic trafficking of matrix metalloproteinase 14: a novel mechanism for blocking mesenchymal cell invasion and metastasis of breast cancer.

NEDD9 is an established marker of invasive and metastatic cancers. NEDD9 downregulation has been shown to dramatically reduce cell invasion and metastasis in multiple tumors. The mechanisms by which NEDD9 regulates invasion are largely unknown. In the current study, we have found that NEDD9 is required for matrix metalloproteinase 14 (MMP14) enzymatic recovery/recycling through the late endosomes to enable disengagement of tissue inhibitor of matrix metalloproteinase 2 (TIMP2) and tumor invasion. Depletion of NEDD9 decreases targeting of the MMP14/TIMP2 complex to late endosomes and increases trafficking of MMP14 from early/sorting endosomes back to the surface in a small GTPase ADP ribosylation factor-6 (Arf6)-dependent manner. NEDD9 directly binds to Arf6-GTPase-activating protein, ARAP3 and Arf6-effector GGA3, thereby facilitating the Arf6 inactivation required for MMP14/TIMP2 targeting to late endosomes. Re-expression of NEDD9 or a decrease in Arf6 activity is sufficient to restore MMP14 activity and the invasive properties of tumor cells. Importantly, NEDD9 inhibition by Vivo-Morpholinos, an antisense therapy, decreases primary tumor growth and metastasis in xenograft models of breast cancer. Collectively, our findings uncover a novel mechanism to control tumor-cell dissemination through NEDD9/Arf6-dependent regulation of MMP14/TIMP2 trafficking, and validate NEDD9 as a clinically relevant therapeutic target to treat metastatic cancer.

Combination of Eribulin and Aurora A Inhibitor MLN8237 Prevents Metastatic Colonization and Induces Cytotoxic Autophagy in Breast Cancer

Recent findings suggest that the inhibition of Aurora A (AURKA) kinase may offer a novel treatment strategy against metastatic cancers. In the current study, we determined the effects of AURKA inhibition by the small molecule inhibitor MLN8237 both as a monotherapy and in combination with the microtubule-targeting drug eribulin on different stages of metastasis in triple-negative breast cancer (TNBC) and defined the potential mechanism of its action. MLN8237 as a single agent and in combination with eribulin affected multiple steps in the metastatic process, including migration, attachment, and proliferation in distant organs, resulting in suppression of metastatic colonization and recurrence of cancer. Eribulin application induces accumulation of active AURKA in TNBC cells, providing foundation for the combination therapy. Mechanistically, AURKA inhibition induces cytotoxic autophagy via activation of the LC3B/p62 axis and inhibition of pAKT, leading to eradication of metastases, but has no effect on growth of mammary tumor. Combination of MLN8237 with eribulin leads to a synergistic increase in apoptosis in mammary tumors, as well as cytotoxic autophagy in metastases. These preclinical data provide a new understanding of the mechanisms by which MLN8237 mediates its antimetastatic effects and advocates for its combination with eribulin in future clinical trials for metastatic breast cancer and early-stage solid tumors. Mol Cancer Ther; 15(8); 1809–22. ©2016 AACR.

Prometastatic NEDD9 Regulates Individual Cell Migration via Caveolin-1-Dependent Trafficking of Integrins.

The dissemination of tumor cells relies on efficient cell adhesion and migration, which in turn depends upon endocytic trafficking of integrins. In the current work, it was found that depletion of the prometastatic protein, NEDD9, in breast cancer cells results in a significant decrease in individual cell migration due to impaired trafficking of ligand-bound integrins. NEDD9 deficiency does not affect the expression or internalization of integrins but heightens caveolae-dependent trafficking of ligand-bound integrins to early endosomes. Increase in mobility of ligand-bound integrins is concomitant with an increase in tyrosine phosphorylation of caveolin-1 (CAV1) and volume of CAV1-vesicles. NEDD9 directly binds to CAV1 and colocalizes within CAV1 vesicles. In the absence of NEDD9, the trafficking of ligand-bound integrins from early to late endosomes is impaired, resulting in a significant decrease in degradation of ligand–integrin complexes and an increase in recycling of ligand-bound integrins from early endosomes back to the plasma membrane without ligand disengagement, thus leading to low adhesion and migration. Reexpression of NEDD9 or decrease in the amount of active, tyrosine 14 phosphorylated (Tyr14) CAV1 in NEDD9-depleted cells rescues the integrin trafficking deficiency and restores cellular adhesion and migration capacity. Collectively, these findings indicate that NEDD9 orchestrates trafficking of ligand-bound integrins through the attenuation of CAV1 activity. Implications: This study provides valuable new insight into the potential therapeutic benefit of NEDD9 depletion to reduce dissemination of tumor cells and discovers a new regulatory role of NEDD9 in promoting migration through modulation of CAV1-dependent trafficking of integrins. Mol Cancer Res; 13(3); 423–38. ©2014 AACR.

Dual Targeting of Mesenchymal and Amoeboid Motility Hinders Metastatic Behavior

Commonly upregulated in human cancers, the scaffolding protein NEDD9/HEF1 is a known regulator of mesenchymal migration and cancer cell plasticity. However, the functional role of NEDD9 as a regulator of different migration/invasion modes in the context of breast cancer metastasis is currently unknown. Here, it is reported that NEDD9 is necessary for both mesenchymal and amoeboid individual cell migration/invasion in triple-negative breast cancer (TNBC). NEDD9 deficiency results in acquisition of the amoeboid morphology, but severely limits all types of cell motility. Mechanistically, NEDD9 promotes mesenchymal migration via VAV2-dependent Rac1 activation, and depletion of VAV2 impairs the ability of NEDD9 to activate Rac1. In addition, NEDD9 supports a mesenchymal phenotype through stimulating polymerization of actin via promoting CTTN phosphorylation in an AURKA-dependent manner. Interestingly, an increase in RhoA activity in NEDD9-depleted cells does not facilitate a switch to functional amoeboid motility, indicating a role of NEDD9 in the regulation of downstream RhoA signaling effectors. Simultaneous depletion of NEDD9 or inhibition of AURKA in combination with inhibition of the amoeboid driver ROCK results in an additional decrease in cancer cell migration/invasion. Finally, we confirmed that a dual targeting strategy is a viable and efficient therapeutic approach to hinder the metastasis of breast cancer in xenograft models, showcasing the important need for further clinical evaluation of this regimen to impede the spread of disease and improve patient survival. Implications: This study provides new insight into the therapeutic benefit of combining NEDD9 depletion with ROCK inhibition to reduce tumor cell dissemination and discovers a new regulatory role of NEDD9 in the modulation of VAV2-dependent activation of Rac1 and actin polymerization. Mol Cancer Res; 15(6); 670–82. ©2017 AACR.

Abstract 2013: NEDD9 depletion leads to MMP14 inactivation by TIMP2 and prevents invasion and metastasis

The scaffolding protein NEDD9 is an established pro-metastatic marker in several cancers. Nevertheless, the molecular mechanisms of NEDD9 driven metastasis in cancers remain ill defined. Here, using a comprehensive breast cancer (BCa) tissue microarray, we show that increased levels of NEDD9 protein significantly correlated with the transition from carcinoma in situ to invasive carcinoma. NEDD9 expression is crucial for the mesenchymal invasion of cancer cells at the primary site but not at the metastatic site. Depletion of NEDD9 is sufficient to suppress invasion, leading to decrease in circulating tumor cells (CTCs) and lung metastases in xenograft models. Mechanistically, NEDD9 localizes to invasive pseudopods and is required for local matrix degradation via regulation of MMP14 trafficking. Depletion of NEDD9 impaired invasion of cancer cells through inactivation of MMP14 by excess TIMP2 on the cell surface. Re-expression of NEDD9 is sufficient to restore the activity of MMP14 and the invasive properties of BCa cells. Collectively, these findings uncover critical steps in invasion of BCa cells with potential strategy to target metastasis through manipulation of NEDD9. Citation Format: Elena N. Pugacheva, Sarah McLaughlin, Ryan Ice, Anuradha Rajulapati, Polina Kozyulina, Ryan Livengood, Varvara Kozyreva, Yuriy Loskutov, Alexey Ivanov, Scott Weed. NEDD9 depletion leads to MMP14 inactivation by TIMP2 and prevents invasion and metastasis. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2013. doi:10.1158/1538-7445.AM2014-2013

Abstract A66: NEDD9 promotes cell invasion through modulation of ARF6 activity and endocytic recycling

The adhesion scaffolding protein NEDD9 was identified as potential pro-metastatic gene in several cancers. The molecular mechanisms of NEDD9-driven metastasis are still unknown. In this study, we show that expression of NEDD9 positively correlates with the invasive stage of breast cancer. We show that NEDD9 localizes to invadopodia and endosomes. Notably, NEDD9 depleted cells have increased levels of inactive surface receptors due to increase in fast recycling of Rab4 and Rab5 positive vesicles. Mechanistically, we found that NEDD9 binds to and scaffolds the Arf6 specific GAP - ASAP3, decreasing Arf6 activity. Thus, depletion of NEDD9 leads to activation of Arf6. Inhibition of Arf6 or re-expression of NEDD9 in shNEDD9 cells was sufficient to restore recycling rates, decrease the number of Rab4 and 5 positive vesicles and the invasive properties of tumor cells. Thus, in this work, we uncover the mechanistic basis of NEDD9-driven invasion and identify a new role for NEDD9 in Arf6-dependant endocytosis. Citation Format: Elena N. Pugacheva, Yuriy Loskutov, Sarah McLaughlin, Polina Kozyulina, Varvara Kozyreva, Ryan Ice, Mark Culp, Robert Wysolmerski, Scott Weed, Alexey Ivanov. NEDD9 promotes cell invasion through modulation of ARF6 activity and endocytic recycling. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr A66.

Abstract 3782: NEDD9 promotes cell invasion through modulation of Arf6-dependent endocytic recycling.

The adaptor protein, NEDD9, is an established pro-metastatic trigger in several cancers but the molecular mechanisms behind NEDD9-driven invasion remain unclear. Here we show that expression of NEDD9 protein tightly correlates with the transition of breast cancer to invasive stages. Overexpression of NEDD9 is critical for the invasion of cancer cells but depletion of NEDD9 is sufficient to block invasion. It is also well established that invadopodia are important for cell invasion. We demonstrate that NEDD9 localizes to invadopodia and its depletion leads to a deficiency in matrix degradation. NEDD9 depletion was also accompanied by an increase in surface levels of inactive proteases (MT1-MMP) and adhesion receptors (integrins). In addition, depletion of NEDD9 induced an increase in recycling and early endosomes via activation of Arf6. NEDD9 binds to the Arf6 specific GAP, ASAP3, which explains NEDD9 modulation of Arf6 activity. Inhibition of Arf6 or re-expression of NEDD9 rescue in NEDD9-deficient cells is sufficient to restore proper recycling rates and invasive properties of breast cancer cells. These results reveal the mechanism behind NEDD9-driven migration and tumor invasion. Citation Format: Yuriy Loskutov, Sarah McLaughlin, Polina Kozyulina, Varvara Kozyreva, Ryan Ice, Anuradha Rajulapati, Mark Culp, Robert Wysolmerski, Alexey Ivanov, Scott Weed, Elena Pugacheva. NEDD9 promotes cell invasion through modulation of Arf6-dependent endocytic recycling. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3782. doi:10.1158/1538-7445.AM2013-3782

Abstract 4934: The role of Aurora A kinase-dependent phosphorylation of cortactin in invadopodia formation.

Aurora A kinase (AURKA) is a serine/threonine kinase known for its critical role in regulation of cell cycle progression. Overexpression and activation of AURKA is implicated in development of multiple types of human cancer. AURKA upregulation is considered as independent prognostic marker for breast cancer patients and associated with poor survival outcome. Recent work by our laboratory and others suggests a new role for AURKA in promotion of tumor cells migration and invasion through regulation of actin dynamics. However, the specific manner in which AURKA regulates actin-based machinery of migrating cancer cells is unknown. In our current work we show that phosphorylation of cortactin (CTTN) by AURKA directly regulates actin dynamics in breast cancer cells. CTTN is known to be regulated by oncogenic Src kinase. This phosphorylation is pivotal for formation of free barbed ends and further actin polymerization. Dynamic polymerization/depolimerization is required for invasion of cancer cells. Thus inhibition of Src-dependant phosphorylation of CTTN is critical for invadopodia maturation. In our current work we identify the phosphorylation site on CTTN targeted by AURKA and show that phosphorylation of CTTN by AURKA could potentially inhibit further phosphorylation of CTTN by Src leading to stabilization of invadopodia. Inhibition of AURKA activity or depletion of AURKA in cancer cells led to decrease in invasion and invadopodia maturation. In addition, we showed that adaptor protein NEDD9 which is known to bind both AURKA and Src also binds to CTTN and therefore potentially can mediate Src-CTTN-AURKA complex formation that regulates the sequential phosphorylation events necessary for invadopodia genesis. It is our expectation that AURKA-phosphorylated CTTN will inhibit Src-driven tyrosine-phosphorylation of CTTN, regulating a mechanistic switch between complementary actin polymerization and actin stabilization programs. Citation Format: Varvara K. Kozyreva, Laura Kelley, Sarah L. McLaughlin, Elena N. Pugacheva. The role of Aurora A kinase-dependent phosphorylation of cortactin in invadopodia formation. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4934. doi:10.1158/1538-7445.AM2013-4934