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    Topic review

    Src Kinases as Therapeutic Targets

    Subjects: Oncology
    View times: 325
    Submitted by: Adriano Angelucci

    Definition

    Src is the prototypal member of Src Family tyrosine Kinases (SFKs), a large non-receptor kinase class that controls multiple signaling pathways in animal cells. SFKs activation is necessary for the mitogenic signal from many growth factors, but also for the acquisition of migratory and invasive phenotype. Indeed, oncogenic activation of SFKs has been demonstrated to play an important role in solid cancers; promoting tumor growth and formation of distant metastases. Several drugs targeting SFKs have been developed and tested in preclinical models and many of them have successfully reached clinical use in hematologic cancers. Although in solid tumors SFKs inhibitors have consistently confirmed their ability in blocking cancer cell progression in several experimental models; their utilization in clinical trials has unveiled unexpected complications against an effective utilization in patients.

    1. Introduction

    Non-receptor tyrosine kinases represent a large cytosolic enzyme family, the most representative of which in mammals is the Src Family tyrosine Kinases (SFKs), including Src, the first ever described tyrosine kinase proto-oncogene. To date tyrosine kinases (TKs) represent also the most representative class of targeted proteins in anticancer therapy [1]. Ten additional kinases with homology to Src have been identified: Blk (B-lymphoid tyrosine kinase), Fgr (gardner-rasheed feline sarcoma), Fyn (proto-oncogene tyrosine-protein kinase Fyn), Frk (Fyn-related kinase), Hck (hematopoietic cell kinase), Lck (lymphocyte specific kinase), Lyn (tyrosine-protein kinase Lyn), Yes (yamaguchi sarcoma), Yrk (Yes-related kinase), and Srms (Src-related kinase lacking C-terminal regulatory tyrosine and N-terminal myristylation sites) [2][3][4].

    Although several studies have demonstrated the presence of some functional redundancy between co-expressed SFKs, there is also plenty of evidence for non-overlapping functions. However, of the 11 SFK members, Src, Fyn, and Yes have been most frequently implicated in tumorigenesis and metastasis formation [5]. Indeed, Src, Fyn, and Yes, but also Frk, are widely expressed in a variety of tissues, whereas for the other members the protein expression is more tissue-restricted with a prevalence in cells of hematopoietic origin. Nonetheless, in contrast to the widely characterized agonistic role of SFKs in cancer, noteworthy specific examples of antagonistic role have been reported. Frk was described as tumor suppressor in different cancers, at least partly by protecting the tumor suppressor Phosphatase and TENsin homolog (PTEN) from degradation [6]. However, other reports of a potential pro-oncogenic function of Frk also exist, such as in studies evaluating the therapeutic potential of SFKs in liver and pancreatic cancer cell lines [7][8]. At status quo, the cellular roles of SFKs, specifically in the context of cell proliferation and invasion, should be evaluated on a tissue-specific basis and identification and characterization their cellular substrates will be helpful in deciphering the context-specific function of SFKs.

    Yrk has been described only in adult chicken and it was detected in hematopoietic cells, cerebellum, spleen, lung, and skin [9][10]. In solid tumors, an increased expression of many members of the family was generally observed, and also for those SFKs with a prevalent expression in normal hematological cells, a de novo presence was frequently reported in non-hematological cancer tissues (Table 1) [11][12].

    Elevated protein levels were shown for Src, Frk, Lyn, Blk, Hck, and Srms, in different tumors, with Yes that demonstrated the highest number of positive cases in a variety of tumors.

    SFKs interact directly with several tyrosine kinase receptors, G-protein-coupled receptors, steroid receptors, signal transducers, and activators of transcription, leading to a diverse array of biological functions from cell survival to metastases [13]. The importance of SFKs in metastatic spreading is a consolidated evidence and it has been associated with different mechanisms including the promotion of tumor cell motility, epithelial-to-mesenchymal transition (EMT) as well as adaptation of resident cells in the secondary microenvironment [14][15].

    Specifically, Src overexpression or overactivation was associated with the aberrant formation of invadopodia, critical morphological structures employed by cancer cells to intravasate into the bloodstream and extravasate into secondary sites during the metastatic process [16][17].

    In addition, Src is a potential target in tumor associated cells. In fact, Src kinase inhibition counteracts those mechanisms underlining some tumor-induced phenotypic switches, including stimulation of cancer associated fibroblasts (CAFs), angiogenesis, and immune infiltrate [18][19][20]. Although Src is ubiquitously expressed, the primary phenotype associated with mutant Src−/− mice is osteopetrosis, a condition caused by the failure to resorb bone. This phenotype results from the blockade of osteoclast maturation and in particular from the inhibition of actin dynamics and its organization, a phenomenon essential in resorbing bone [21]. These data have designated Src as an attractive therapeutic target for the prevention and treatment of bone metastases [22].

    Table 1. Distribution of Src Family tyrosine Kinase (SFK) proteins in normal and solid tumor tissues according to Human Protein Atlas database available from http://www.proteinatlas.org.

    Protein Kinase

    Tissue Distribution

    Solid Tumor Distribution

    Level of Expression

    Tumor (*)

    Src

    most

    strong

    cervical, head and neck, pancreatic, skin, urothelial

    moderate

    colorectal, lung, stomach

    weak

    carcinoid, cervical

    Yes

    most

    moderate

    most (>60% = breast, colorectal, head and neck, liver, ovarian, prostate, testis, thyroid, urothelial)

    Frk

    most

    strong

    thyroid

    weak to moderate

    carcinoid, colorectal, endometrial, liver, melanoma, renal, urothelial

    Lyn

    most

    moderate to strong

    liver, stomach

    weak

    carcinoid, head and neck, thyroid

    Fyn

    brain, endocrine tissues, female tissues, hematopoietic cells, liver

    moderate

    glioma

    weak

    carcinoid, thyroid

    Blk

    hematopoietic cells, lung

    moderate to strong

    endometrial

    Fgr

    hematopoietic cells, lung

    weak

    Carcinoid, colorectal, renal, thyroid

    Hck

    hematopoietic cells, lung

    strong

    endometrial, lung, renal, stomach

    weak

    carcinoid, glioma, liver, ovarian, pancreas, skin

    Lck

    hematopoietic cells

    negative

    none

    Srms

    gastrointestinal, male tissue (**)

    strong

    colorectal, ovarian, prostate

    moderate

    most

    * only positivity >20% cases are reported; ** based on mRNA expression.

    2. SFKs Structure and Regulation

    SFKs display large sequence and structural similarity. The most variable long sequence among SFKs is localized in the “unique domain” connecting the SH3 and SH4 domains, but to which has been assigned specific regulatory role only in few cases [23][24][25][26][27][28][29][30][31][32][33][34][35]. Src, the prototype kinase of SFKs, is a 60-kDa protein able to associate with the plasma, perinuclear, and endosomal membrane via a N-terminal anchoring region that includes the SH4 domain, rich in positively charged residues [36]. During intense cytoskeleton dynamic and cell migration, SFKs are targeted to focal adhesions (FAs), a phenomenon that is regulated mainly by the SH2 domain [37]. Recent studies have reported the presence of Src also in the nuclear compartment, and this localization seems to be relevant in the progression of some solid tumors [38][39]. While the Src enzymatic activity is localized in the SH1 domain, the SH2 and SH3 domain through intra-protein and protein–protein interaction can control the catalytic activity and the recognition of substrates. In fact, protein–protein interaction and Tyr phosphorylation status determine the existence of a dynamic equilibrium between closed-inactive and open-active form of SFKs. The open conformation allows the phosphorylation of Tyr419 (in human Src) in the activation cycle, which improves catalytic activity. In the canonical pathway, Src activation is initiated by dephosphorylation of pTyr530 (in human Src) followed by a conformational change that permits autophosphorylation at Tyr419 with full activation [40].

    In all SFKs an important activation control is exerted by phosphorylation status in C-terminal Tyr residues (Tyr530 in human Src). The phosphorylation of Tyr530 determines conformational changes leading to intramolecular interaction with the SH2 domain and inactivating kinase activity [24]. The close association between spatial conformation and kinase activation, obligates researchers to carefully consider the interacting ability of SFKs with other proteins in critical cell compartments. The SH3 domain, consisting of 50–60 amino acids, binds proline rich sequences and it can interact with the linker domain (PPII-linker) on the back of the catalytic domain, thus promoting a "closed" conformation that prevents interaction with substrates. Several ligands are known to compete with the SH3/PPII-linker interaction: the progesterone receptor, p130Cas, AFAP-110, and Nef. The SH2 domain, consisting of about 100 amino acid residues, binds phosphorylated Tyr residues in C-terminal domain in the inactive conformation or, in the active form, on other proteins [25]. In the open form, the inhibitory tyrosine residues are accessible to phosphatase and dephosphorylation coincides with the destruction of all intramolecular interactions and the phosphorylation of the activating site that induces a complete kinase activation. Phosphorylation of pTyr530 works in conjunction with dephosphorylation of pTyr419, mediated by proline-enriched tyrosine phosphatase (PEP), in allowing the complete inactivation of SFKs in vivo [26]. However, the binding with external ligands still allows SFKs to open its spatial conformation and to remain active even in the presence of terminal C-tail phosphorylation. This indicates that phosphorylation of inhibitory tyrosine and the resulting intramolecular interaction are not sufficient to maintain SFK activity in a complete inhibited status in vivo [27]. In agreement with a context-dependent activation model, experimental evidence suggests that the activated phosphatase CD45 can also function as a negative regulator of SFK by dephosphorylating pTyr419 [28].

    During tumor progression, Src activity becomes abnormally high and since activating mutations or amplification are very rare in human Src, an altered extrinsic control of phosphorylation by kinase or phosphatase and of interacting partners may represent an important mechanism for activation of Src. The phosphorylation of Tyr530 is determined by the action of different tyrosine kinases including Csk (C-terminal Src kinase) and Chk (Csk-homologous kinase) [29]. Csk kinase acts as the main negative regulator of Src and under basal conditions in vivo, 90–95% of Src is phosphorylated in Tyr530. The importance of phosphorylation of Tyr530 in the mechanism of inhibition of Src kinase activity is suggested by experimental evidence in which knockout mutant shows a constitutive basal activity associated with oncogenic transformation [30]. Several tyrosine phosphatases (PTPs) are involved in terminal C-tail dephosphorylation mechanism. Their role in SFK regulation is complex showing tumor specificity and specific roles for the different members of the kinase family.

    PTP1B phosphatase, which is upregulated in many human solid tumors as colon, lung, and breast cancer, is responsible for the dephosphorylation of Tyr530 and subsequent activation of Src and therefore, for increased tumorigenicity [31][32]. CD45, abundantly expressed in all nucleated cells of hematopoietic origin, is the most important phosphatase activating SFKs by dephosphorylation of the terminal C-tail [33]. In contrast to Lck and Fyn, the Src C-terminal phosphotyrosine does not appear subject to dephosphorylation by CD45 [34]. SHP-1 and SHP-2 are two tyrosine phosphatases localized in cytosol. SHP-1 is primarily present in cells of hematopoietic origin, SHP-2 is ubiquitous and experimental evidence has established that SHP-1 is involved in dephosphorylating and activation of Src [35]. However, SHP-1 and CD45 are also able to dephosphorylate Tyr-394 in the catalytic domain of Lck and to inactivate Lck, but not Src, suggesting that these phosphatases are not involved only in activation of SFKs but also in the modulation of their specificity [41][42]. SHP-2 can regulate SFKs activity in several ways: by an enzymatic mechanism involving terminal C-tail dephosphorylation, and a non-enzymatic mechanism linked to the control of Csk recruitment to the plasma membrane. In this case, SHP-2 catalyzes the dephosphorylation of the PAG protein (phosphoprotein associated with glycosphingolipid-enriched microdomains), which in turn are unable to recruit Csk. Thus, the activity of SHP-2 can result in the failure to activate the inhibitory control of Csk in membrane-associated complexes containing SFKs [43].

    3. SFKs in Cancer Signal Transduction, Migration, and Invasion

    Since the original identification of a transmissible agent responsible for the development of solid tumors in chickens, now known to be a retrovirus encoding the v-SRC, significant progress has been made in defining the functions of its human homolog, Src [44]. One of the aspects associated with oncogenic potential that emerged early on from the studies, was the ability of SFKs to stimulate cell motility. The relationship between Src activation and cancer invasion, the most advanced phase of solid tumor progression, appears to be significant in a wide number of preclinical human cancer models, thus prompting the optimistic use of SFK inhibitors in clinical trials [45]. The SH3 domain of SFKs permits the association with actin filaments that guide the translocation of SFKs towards the cell periphery where they can interact with other molecular partners allowing two major transduction events: (i) signaling from growth factor receptors, which mainly affects cell growth, (ii) signaling from adhesion receptors including integrins and E-cadherin, which mainly regulate the functions of the cytoskeleton [46]. To date, most evidence suggests that Src has a predominant role in the maintenance of the invasive phenotype, rather than of the cell cycle progression. FA junctions, that are key structure in regulating cell motility, are formed by the docking activity of SFKs, through the accessibility of SH2 domain.

    FAs are protein complexes that play a critical role in dynamically controlling the coupling of actin filaments and the extracellular matrix. During migration, integrins, heterodimeric transmembrane receptors bind directly to the extracellular matrix (ECM) on the outside of the cell and link ECM to the actin cytoskeleton through FA. In turn, FAs contain signaling proteins that regulate cytoskeletal dynamics, including changes in actinomyosin contractility. The formation of FAs is dependent on the phosphorylation status and the presence of docking sites in participating proteins. SFKs can regulate the phosphorylation status of many substrates in the FA and participate directly in the formation of the complex through the docking site SH2. Src associates with FA in FAK-dependent manner. In addition, the association of Src with FAs plays a key role in transducing Src-mediated signals, in the promotion of FA formation/maturation and in enhancing cell migration. Src substrates in FA include FAK, p130Cas, tensins, paxillin, and crk[47][48]. Src and FAK in their activated states, form a functional bipartite kinase complex that is fundamental in the signal transduction and in formation of lamellipodia. In fact, phosphorylation of p130Cas by the FAK/Src complex provides a binding site for the SH2 domain of CrkII, which in turn serves as a docking site for Rac1 [49]. Involvement in FA activity has been described also for other members of SFKs including Fyn [50] and Yes, and through the use of deleted-mutant SFY (src-/-fyn-/-yes-/-) it was demonstrated a strong dependence of cancer cell migration and metastatic ability on these kinases [51]. Invadosomes, which include invadopodia, are F-actin based structures used by cancer cells to interact with and to degrade ECM. These structures were initially discovered in v-Src transformed chicken fibroblasts. Src may target different actin-binding proteins during distinct stages of invadosome formation and maturation to regulate actin dynamics and invadosome function. Various signaling pathways have been shown to be involved in the formation of invadosomes, resulting in focally releasing of metalloproteases (MMPs) that degrade ECM. During invadosome precursor formation, signaling proteins such as transmembrane growth factor receptors and/or SFKs organize with structural and adaptor proteins including Tks5, Nck1, and cortactin to recruit the Arp2/3 complex and mediate actin polymerization [52]. Cortactin is a multi-functional Src substrate that is involved in both the assembly and maturation of invadosomes and is important for invasive cell migration [53][54]. Src phosphorylates cortactin at three sites, Y421, Y466, and Y482, and cortactin phosphorylation is important for the formation of invadopodia [55]. In addition to its effects on the actin-severing activity of cofilin, phosphorylated cortactin facilitates actin polymerization through its interactions with N-WASP and Arp2/3 [56][57]. MAbp1, in contrast to cortactin, impairs invadopodia formation and invasive cell migration and it is phosphorylated by Src at two sites, Y337 and Y347 [58]. The spatiotemporal phosphorylation of cortactin and mAbp1 can regulate invadosome dynamics, with cortactin present at invadopodia during early assembly and stabilization, while mAbp1 is present at mature podosome dots [58][59]. Src is necessary also during invadosome disassembly. Src phosphorylates paxillin, which through Erk signaling, activates the protease Calpain-2, which in turn cleaves multiple invadosome proteins including paxillin and cortactin.

    Migration and invasion are acquired abilities in epithelial tumor cells and require the disassembly of adherent and tight-junctions and the inhibition of anoikis. These latter transformations are early steps in the EMT suggesting a role for SFKs in this phenomenon. Importantly, Src plays a control role in the expression of E-cadherin. Src inhibition induces in breast cancer cells a reverted epithelial phenotype associated with an increase of E-cadherin and a decrease of vimentin and it blocks cancer cell migration [60]. Oncogenic expression of Src in pancreatic tumor cells was also associated with a reduced expression of E-cadherin in favor of vimentin [61]. Similar results were obtained also in other tumors including prostate and renal cancer [62]. Given the involvement of SFKs activity in the EMT, cancer migration and invasion, Src family represents an attractive target for advanced stages of cancer progression.

    This entry is adapted from 10.3390/cancers12061448

    References

    1. Angelucci, A. Targeting Tyrosine Kinases in Cancer: Lessons for an Effective Targeted Therapy in the Clinic. Cancers 2019, 11, 490.
    2. Kim, L.C.; Song, L.; Haura, E.B. Src kinases as therapeutic targets for cancer. Nat. Rev. Clin. Oncol. 2009, 6, 587–595.
    3. Rai, K. Personalized Cancer Therapy: YES1 Is the New Kid on the Block. Cancer Res. 2019, 79, 5702–5703.
    4. Kohmura, N.; Yagi, T.; Tomooka, Y.; Oyanagi, M.; Kominami, R.; Takeda, N.; Chiba, J.; Ikawa, Y.; Aizawa, S. A novel nonreceptor tyrosine kinase, Srm: Cloning and targeted disruption. Mol. Cell. Biol. 1994, 14, 6915–6925.
    5. Stein, P.L.; Vogel, H.; Soriano, P. Combined deficiencies of Src, Fyn, and Yes tyrosine kinases in mutant mice. Genes Dev. 1994, 8, 1999–2007.
    6. Yim, E.K.; Peng, G.; Dai, H.; Hu, R.; Li, K.; Lu, Y.; Mills, G.B.; Meric-Bernstam, F.; Hennessy, B.T.; Craven, R.J.; et al. Rak functions as a tumor suppressor by regulating PTEN protein stability and function. Cancer Cell 2009, 15, 304–314.
    7. Chen, J.S.; Hung, W.S.; Chan, H.H.; Tsai, S.J.; Sun, H.S. In silico identification of oncogenic potential of fyn-related kinase in hepatocellular carcinoma. Bioinformatics 2013, 29, 420–427.
    8. Je, D.W.; Ji, Y.G.; Cho, Y.; Lee, D.H. The inhibition of SRC family kinase suppresses pancreatic cancer cell proliferation, migration, and invasion. Pancreas 2014, 43, 768–776.
    9. Sudol, M.; Greulich, H.; Newman, L.; Sarkar, A.; Sukegawa, J.; Yamamoto, T. A novel Yes-related kinase, Yrk, is expressed at elevated levels in neural and hematopoietic tissues. Oncogene 1993, 8, 823–831.
    10. Martins-Green, M.; Bixby, J.L.; Yamamoto, T.; Graf, T.; Sudol, M. Tissue specific expression of Yrk kinase: Implications for differentiation and inflammation. Int. J. Biochem. Cell B 2000, 32, 351–364.
    11. Uhlen, M.; Fagerberg, L.; Hallstrom, B.M.; Lindskog, C.; Oksvold, P.; Mardinoglu, A.; Sivertsson, A.; Kampf, C.; Sjostedt, E.; Asplund, A.; et al. Proteomics. Tissue-based map of the human proteome. Science 2015, 347, 1260419.
    12. Uhlen, M.; Zhang, C.; Lee, S.; Sjostedt, E.; Fagerberg, L.; Bidkhori, G.; Benfeitas, R.; Arif, M.; Liu, Z.; Edfors, F.; et al. A pathology atlas of the human cancer transcriptome. Science 2017, 357, eaan2507.
    13. Wheeler, D.L.; Iida, M.; Dunn, E.F. The role of Src in solid tumors. Oncologist 2009, 14, 667–678.
    14. Logue, J.S.; Cartagena-Rivera, A.X.; Chadwick, R.S. c-Src activity is differentially required by cancer cell motility modes. Oncogene 2018, 37, 2104–2121.
    15. Zhao, L.; Li, X.; Song, N.; Li, A.; Hou, K.; Qu, X.; Che, X.; Liu, Y. Src promotes EGF-induced epithelial-to-mesenchymal transition and migration in gastric cancer cells by upregulating ZEB1 and ZEB2 through AKT. Cell Biol Int 2018, 42, 294–302.
    16. Bailey, K.M.; Airik, M.; Krook, M.A.; Pedersen, E.A.; Lawlor, E.R. Micro-Environmental Stress Induces Src-Dependent Activation of Invadopodia and Cell Migration in Ewing Sarcoma. Neoplasia 2016, 18, 480–488.
    17. Ngan, E.; Stoletov, K.; Smith, H.W.; Common, J.; Muller, W.J.; Lewis, J.D.; Siegel, P.M. LPP is a Src substrate required for invadopodia formation and efficient breast cancer lung metastasis. Nat. Commun. 2017, 8, 15059.
    18. Calgani, A.; Vignaroli, G.; Zamperini, C.; Coniglio, F.; Festuccia, C.; Di Cesare, E.; Gravina, G.L.; Mattei, C.; Vitale, F.; Schenone, S.; et al. Suppression of SRC Signaling Is Effective in Reducing Synergy between Glioblastoma and Stromal Cells. Mol. Cancer Ther. 2016, 15, 1535–1544.
    19. Delle Monache, S.; Sanita, P.; Calgani, A.; Schenone, S.; Botta, L.; Angelucci, A. Src inhibition potentiates antitumoral effect of paclitaxel by blocking tumor-induced angiogenesis. Exp. Cell Res. 2014, 328, 20–31.
    20. Liu, S.T.; Pham, H.; Pandol, S.J.; Ptasznik, A. Src as the link between inflammation and cancer. Front. Physiol. 2013, 4, 416.
    21. Destaing, O.; Sanjay, A.; Itzstein, C.; Horne, W.C.; Toomre, D.; De Camilli, P.; Baron, R. The tyrosine kinase activity of c-Src regulates actin dynamics and organization of podosomes in osteoclasts. Mol. Biol. Cell 2008, 19, 394–404.
    22. Myoui, A.; Nishimura, R.; Williams, P.J.; Hiraga, T.; Tamura, D.; Michigami, T.; Mundy, G.R.; Yoneda, T. C-SRC tyrosine kinase activity is associated with tumor colonization in bone and lung in an animal model of human breast cancer metastasis. Cancer Res. 2003, 63, 5028–5033.
    23. Summy, J.M.; Gallick, G.E. Src family kinases in tumor progression and metastasis. Cancer Metastasis Rev. 2003, 22, 337–358.
    24. Chen, M.L.; Chai, C.Y.; Yeh, K.T.; Wang, S.N.; Tsai, C.J.; Yeh, Y.T.; Yang, S.F. Crosstalk between activated and inactivated c-Src in hepatocellular carcinoma. Dis. Markers 2011, 30, 325–333.
    25. Boggon, T.J.; Eck, M.J. Structure and regulation of Src family kinases. Oncogene 2004, 23, 7918–7927.
    26. Mustelin, T.; Tasken, K. Positive and negative regulation of T-cell activation through kinases and phosphatases. Biochem. J. 2003, 371, 15–27.
    27. Chong, Y.P.; Ia, K.K.; Mulhern, T.D.; Cheng, H.C. Endogenous and synthetic inhibitors of the Src-family protein tyrosine kinases. Biochim. Biophys. Acta 2005, 1754, 210–220.
    28. Furlan, G.; Minowa, T.; Hanagata, N.; Kataoka-Hamai, C.; Kaizuka, Y. Phosphatase CD45 both positively and negatively regulates T cell receptor phosphorylation in reconstituted membrane protein clusters. J. Biol. Chem. 2014, 289, 28514–28525.
    29. Chong, Y.P.; Mulhern, T.D.; Cheng, H.C. C-terminal Src kinase (CSK) and CSK-homologous kinase (CHK)--endogenous negative regulators of Src-family protein kinases. Growth Factors 2005, 23, 233–244.
    30. Kmiecik, T.E.; Shalloway, D. Activation and suppression of pp60c-src transforming ability by mutation of its primary sites of tyrosine phosphorylation. Cell 1987, 49, 65–73.
    31. Abram, C.L.; Courtneidge, S.A. Src family tyrosine kinases and growth factor signaling. Exp. Cell Res. 2000, 254, 1–13.
    32. Bjorge, J.D.; Pang, A.; Fujita, D.J. Identification of protein-tyrosine phosphatase 1B as the major tyrosine phosphatase activity capable of dephosphorylating and activating c-Src in several human breast cancer cell lines. J. Biol. Chem. 2000, 275, 41439–41446.
    33. Wang, D.; Esselman, W.J.; Cole, P.A. Substrate conformational restriction and CD45-catalyzed dephosphorylation of tail tyrosine-phosphorylated Src protein. J. Biol. Chem. 2002, 277, 40428–40433.
    34. Ostergaard, H.L.; Shackelford, D.A.; Hurley, T.R.; Johnson, P.; Hyman, R.; Sefton, B.M.; Trowbridge, I.S. Expression of CD45 alters phosphorylation of the lck-encoded tyrosine protein kinase in murine lymphoma T-cell lines. Proc. Natl. Acad. Sc. USA 1989, 86, 8959–8963.
    35. Somani, A.K.; Bignon, J.S.; Mills, G.B.; Siminovitch, K.A.; Branch, D.R. Src kinase activity is regulated by the SHP-1 protein-tyrosine phosphatase. J. Biol. Chem. 1997, 272, 21113–21119.
    36. Kaplan, K.B.; Bibbins, K.B.; Swedlow, J.R.; Arnaud, M.; Morgan, D.O.; Varmus, H.E. Association of the amino-terminal half of c-Src with focal adhesions alters their properties and is regulated by phosphorylation of tyrosine 527. EMBO J. 1994, 13, 4745–4756.
    37. Wu, J.C.; Chen, Y.C.; Kuo, C.T.; Wenshin Yu, H.; Chen, Y.Q.; Chiou, A.; Kuo, J.C. Focal adhesion kinase-dependent focal adhesion recruitment of SH2 domains directs SRC into focal adhesions to regulate cell adhesion and migration. Sci. Rep. 2015, 5, 18476.
    38. Paladino, D.; Yue, P.; Furuya, H.; Acoba, J.; Rosser, C.J.; Turkson, J. A novel nuclear Src and p300 signaling axis controls migratory and invasive behavior in pancreatic cancer. Oncotarget 2016, 7, 7253–7267.
    39. Urciuoli, E.; Coletta, I.; Rizzuto, E.; De Vito, R.; Petrini, S.; D’Oria, V.; Pezzullo, M.; Milano, G.M.; Cozza, R.; Locatelli, F.; et al. Src nuclear localization and its prognostic relevance in human osteosarcoma. J. Cell Physiol. 2018, 233, 1658–1670.
    40. Amata, I.; Maffei, M.; Pons, M. Phosphorylation of unique domains of Src family kinases. Front. Genet. 2014, 5, 181.
    41. Chiang, G.G.; Sefton, B.M. Specific dephosphorylation of the Lck tyrosine protein kinase at Tyr-394 by the SHP-1 protein-tyrosine phosphatase. J. Biol. Chem. 2001, 276, 23173–23178.
    42. Baker, M.; Gamble, J.; Tooze, R.; Higgins, D.; Yang, F.T.; O’Brien, P.C.; Coleman, N.; Pingel, S.; Turner, M.; Alexander, D.R. Development of T-leukaemias in CD45 tyrosine phosphatase-deficient mutant lck mice. EMBO J. 2000, 19, 4644–4654.
    43. Zhang, S.Q.; Yang, W.; Kontaridis, M.I.; Bivona, T.G.; Wen, G.; Araki, T.; Luo, J.; Thompson, J.A.; Schraven, B.L.; Philips, M.R.; et al. Shp2 regulates SRC family kinase activity and Ras/Erk activation by controlling Csk recruitment. Mol. Cell 2004, 13, 341–355.
    44. Rous, P. A sarcoma of the fowl transmissible by an agent separable from the tumor cells. J. Exp. Med. 1911, 13, 397–411.
    45. Irby, R.B.; Yeatman, T.J. Role of Src expression and activation in human cancer. Oncogene 2000, 19, 5636–5642.
    46. Bjorge, J.D.; Jakymiw, A.; Fujita, D.J. Selected glimpses into the activation and function of Src kinase. Oncogene 2000, 19, 5620–5635.
    47. Gayrard, C.; Bernaudin, C.; Dejardin, T.; Seiler, C.; Borghi, N. Src- and confinement-dependent FAK activation causes E-cadherin relaxation and beta-catenin activity. J. Cell Biol. 2018, 217, 1063–1077.
    48. Zhang, C.; Miller, D.J.; Guibao, C.D.; Donato, D.M.; Hanks, S.K.; Zheng, J.J. Structural and functional insights into the interaction between the Cas family scaffolding protein p130Cas and the focal adhesion-associated protein paxillin. J. Biol. Chem. 2017, 292, 18281–18289.
    49. Hsia, D.A.; Mitra, S.K.; Hauck, C.R.; Streblow, D.N.; Nelson, J.A.; Ilic, D.; Huang, S.; Li, E.; Nemerow, G.R.; Leng, J.; et al. Differential regulation of cell motility and invasion by FAK. J. Cell Biol. 2003, 160, 753–767.
    50. Yeo, M.G.; Oh, H.J.; Cho, H.S.; Chun, J.S.; Marcantonio, E.E.; Song, W.K. Phosphorylation of Ser 21 in Fyn regulates its kinase activity, focal adhesion targeting, and is required for cell migration. J. Cell Physiol. 2011, 226, 236–247.
    51. Chatterji, T.; Varkaris, A.S.; Parikh, N.U.; Song, J.H.; Cheng, C.J.; Schweppe, R.E.; Alexander, S.; Davis, J.W.; Troncoso, P.; Friedl, P.; et al. Yes-mediated phosphorylation of focal adhesion kinase at tyrosine 861 increases metastatic potential of prostate cancer cells. Oncotarget 2015, 6, 10175–10194.
    52. Yamaguchi, H.; Lorenz, M.; Kempiak, S.; Sarmiento, C.; Coniglio, S.; Symons, M.; Segall, J.; Eddy, R.; Miki, H.; Takenawa, T.; et al. Molecular mechanisms of invadopodium formation: The role of the N-WASP-Arp2/3 complex pathway and cofilin. J. Cell Biol. 2005, 168, 441–452.
    53. Oser, M.; Yamaguchi, H.; Mader, C.C.; Bravo-Cordero, J.J.; Arias, M.; Chen, X.; Desmarais, V.; van Rheenen, J.; Koleske, A.J.; Condeelis, J. Cortactin regulates cofilin and N-WASp activities to control the stages of invadopodium assembly and maturation. J. Cell Biol. 2009, 186, 571–587.
    54. Clark, E.S.; Whigham, A.S.; Yarbrough, W.G.; Weaver, A.M. Cortactin is an essential regulator of matrix metalloproteinase secretion and extracellular matrix degradation in invadopodia. Cancer Res. 2007, 67, 4227–4235.
    55. Huang, C.; Liu, J.; Haudenschild, C.C.; Zhan, X. The role of tyrosine phosphorylation of cortactin in the locomotion of endothelial cells. J. Biol. Chem. 1998, 273, 25770–25776.
    56. Tehrani, S.; Tomasevic, N.; Weed, S.; Sakowicz, R.; Cooper, J.A. Src phosphorylation of cortactin enhances actin assembly. Proc. Natl. Acad. Sci. USA 2007, 104, 11933–11938.
    57. Desmarais, V.; Yamaguchi, H.; Oser, M.; Soon, L.; Mouneimne, G.; Sarmiento, C.; Eddy, R.; Condeelis, J. N-WASP and cortactin are involved in invadopodium-dependent chemotaxis to EGF in breast tumor cells. Cell Motil. Cytoskelet. 2009, 66, 303–316.
    58. Boateng, L.R.; Cortesio, C.L.; Huttenlocher, A. Src-mediated phosphorylation of mammalian Abp1 (DBNL) regulates podosome rosette formation in transformed fibroblasts. J. Cell Sci. 2012, 125, 1329–1341.
    59. Artym, V.V.; Zhang, Y.; Seillier-Moiseiwitsch, F.; Yamada, K.M.; Mueller, S.C. Dynamic interactions of cortactin and membrane type 1 matrix metalloproteinase at invadopodia: Defining the stages of invadopodia formation and function. Cancer Res. 2006, 66, 3034–3043.
    60. Liu, X.; Feng, R. Inhibition of epithelial to mesenchymal transition in metastatic breast carcinoma cells by c-Src suppression. Acta Biochim. Biophys. Sin. (Shanghai) 2010, 42, 496–501.
    61. Nagathihalli, N.S.; Merchant, N.B. Src-mediated regulation of E-cadherin and EMT in pancreatic cancer. Front. Biosci. (Landmark Ed) 2012, 17, 2059–2069.
    62. Micalizzi, D.S.; Farabaugh, S.M.; Ford, H.L. Epithelial-mesenchymal transition in cancer: Parallels between normal development and tumor progression. J. Mammary Gland Biol. Neoplasia 2010, 15, 117–134.
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