Dr. Andrew Freywald PhD

              The work of our team focuses on identifying and targeting molecular mechanisms that determine tumor aggressiveness. In our investigations, we use genome-wide screening, high-throughput screening of drug libraries and advanced proteomics approaches in addition to conventional cell biology, tumor biology and biochemistry techniques.

             Cancer cells are often controlled by receptor tyrosine kinases and Eph receptors (EphRs) form the largest group within this family. EphRs are presented by EphA (EphA1-10) and EphB (EphB1-6) types, where EphAs interact mostly with ligands of the ephrin-A group (ephrin-A1-6), while EphBs are activated by ephrin-B ligands (ephrin-B1-3). Although initially identified as EphR ligands, ephrins are expressed on the cell membrane and can also function as active receptors. Both EphRs and ephrins govern a wide range of responses in differentiated cells and in stem cell populations, and are expected to play a central role in controlling tumor behavior.

            Our earlier investigation revealed that ephrin-B1 is strongly expressed in childhood T cell acute lymphoblastic leukaemia (T-ALL). Its action in T-ALL relies on the co-localisation with Rac1, and CrkL cytoskeleton regulators in lipid rafts, allowing ephrin-B1 to support T-ALL invasiveness. The Lck kinase is crucial for ephrin-B1 function and its absence blocks ephrin-B1-induced signaling and invasive activity (Jiang et al., Mol Cancer Res, 2008). Our work in T-ALL also indicates that EphB3 and EphB6 receptors are likely to support T-ALL immunoevasion by activating the Akt kinase, and inhibiting Fas receptor-triggered apoptotic cell death. Therefore, these receptors may represent promising targets in therapies, relying on T-ALL immunoelimination (Maddigan et al., J Immunol, 2011).

           Interestingly, our work with EphB6 reveals that it has different properties in breast cancer, where it blocks invasiveness (Truitt et al., Cancer Research, 2010). EphB6, although being intrinsically kinase-deficient, undergoes phosphorylation, mediated by the EphB4 receptor. Phosphorylated EphB6 interacts with c-Cbl, which allows it to control the Abl kinase and block the invasive response. Despite its role in EphB6 action, EphB4 also acts in EphB6-independent manner to enhance invasion, suggesting that cancer invasiveness and metastasis are defined by a balance between pro-invasive EphB4 signaling and the anti-invasive action of the EphB6-EphB4 complex.

         We determined that EphB6 level is often reduced in breast tumors and EphB6 downregulation helps to target its synthetic lethal partner, Src. EphB6 absence improves tumor elimination by Src inhibition, suggesting that Src inhibitors used in cancer therapy should be applied selectively in EphB6-negative cases (Paul et al., Oncotarget, 2016). Currently, we are working towards initiating phase II clinical trial to translate our finding into clinical applications.

         Unexpectedly, we also found that EphB6 is relatively better preserved in triple-negative subtype of breast cancer (TNBC), where it supports cancer stemness and tumor initiation (Toosi et al., Oncogene, 2018). Moreover, our recent investigation, dissecting the network of cancer-related genetic interactions of all EphRs and ephrins, revealed a functional crosstalk between EphB6 and EGFR, and EphB6 essentiality in EGFR-dependent tumors, providing a context for therapeutic EphB6 targeting (Hanover et al., Cell Reports, 2023).

        To facilitate translation of our findings into new cancer therapies, I am acting as a scientific advisor for a biotech company, Biomirex Inc (MA, USA), and following predictions of our integrated genomics/proteomics-based strategy, we developed with their help and characterized a fully human anti-EGFR/EphA2 bispecific antibody with strong tumor-suppressing properties (El Zawily et al., Clinical Cancer Research, 2023). This antibody is currently being prepared for clinical trials, and we keep working on generating and assessing new antibodies for targeted cancer therapies.

Our research projects and publications are supported by CIHR, SHRF, CRS and TFRI granting agencies, by the Be Like Bruce organization and by funding provided by the College of Medicine, and the University of Saskatchewan.

LAB OPENINGS: e-mail enquiries for Summers Student, Graduate Student and PostDoctoral positions are welcome. Pathology residents are encouraged to get involved in short-term projects.

(the complete list of our publications can be found on the PubMed site: https://pubmed.ncbi.nlm.nih.gov/?term=Freywald+A&sort=date)

• Hanover G, Vizeacoumar FS, Banerjee SL, Nair R, Dahiya R, Osornio-Hernandez AI, Morales AM, Freywald T, Himanen JP, Toosi BM, Bisson N, Vizeacoumar FJ, Freywald A. (2023). Integration of cancer-related genetic landscape of Eph receptors and ephrins with proteomics identifies a crosstalk between EPHB6 and EGFR. Cell Reports.
• El Zawily A, Vizeacoumar SV, Dahiya R, Banerjee SL, Bhanumathy KK, Hussain H, Hanover G, Sharpe JC, Sanchez MG, Greidanus P, Stacey RG, Moon KM, Alexandrov I, Himanen JP, Nikolov DB, Fonge H, White AP, Foster L, Wang B, Toosi BM, Bisson N, Mirzabekov TM, Vizeacoumar FJ, Freywald A. (2023). A Multipronged Unbiased Strategy Guides the Development of an anti-EGFR/EPHA2 Bispecific Antibody for Combination Cancer Therapy. Clinical Cancer Research.
• Toosi B., El Zawily A., Truitt L., Shannon M., Allonby O., Babu M., DeCoteau J., Mousseau D., Ali M., Freywald T., Gall A., Vizeacoumar F.S., Kirzinger M., Geyer R., Anderson D., Kim T., Welm A.L., Siegel P.,Vizeacoumar F.J., Kusalik A., and Freywald A. (2018)  EPHB6 augments both development and drug sensitivity of triple-negative breast cancer tumours. Oncogene.
• El Zawily A., McEwen E., Toosi B., Vizeacoumar F.S., Freywald T., Vizeacoumar F.J., Freywald A. (2017) The EphB6 receptor is overexpressed in pediatric T cell acute lymphoblastic leukemia and increases its sensitivity to doxorubicin treatment. Scientific Reports.
• Auslander N., Cunningham C.E., Toosi B., McEwen E., Yizhak K., Vizeacoumar F.S., Parameswaran S., Gonen N., Freywald T., Bhanumathy K., Freywald A., Vizeacoumar F.J., Ruppin E. (2017) An integrated computational and experimental study uncovers FUT9 as a metabolic driver of colorectal cancer. Molecular Systems Biology.
• Paul J., Toosi B., Vizeacoumar F.S., Bhanumathy K., Li Y., Gerger C., El Zawily A., Freywald T., Anderson D., Mousseau D., Kanthan R., Zhang Z., Vizeacoumar F.J., Freywald A. (2016) Targeting synthetic lethality between the SRC kinase and the EPHB6 receptor may benefit cancer treatment. Oncotarget.
• Jessulat M., Malty R., Nguyen-Tran D., Deineko V., Aoki H., Vlasblom J., Omidi K., Jin K..  Minic Z., Hooshyar M., Burnside D., Samanfar B., Phanse S., Freywald T., Prasad B., Zhang Z., Vizeacoumar F., Krogan N., Freywald A., Golshani A., Babu M. (2015) Spindle Checkpoint Factors Bub1 and Bub2 Promote DNA Double-Strand Break Repair by Nonhomologous End Joining., Molecular and Cellular Biology.
• Allonby O., El Zawily A., Freywald T., Mousseau D., Chlan J., Anderson D., Benmerah A., Sidhu V., Babu M., DeCoteau J., Freywald A. (2014), Ligand stimulation induces clathrin- and Rab5- dependent downregulation of the kinase-dead EphB6 receptor preceded by the disruption of EphB6-Hsp90 interaction., Cellular Signalling.
• Maddigan, A., Truitt, L., Arsenault, R., Freywald T., Allonby O., Dean J., Narendran A.,  Xiang J., Weng A., Napper S. and Freywald A. (2011) EphB receptors trigger Akt activation and suppress Fas receptor-induced apoptosis in malignant T lymphocytes, The Journal of Immunology.
• Truitt L, Freywald A. (2011) Dancing with the dead: Eph receptors and their kinase-null partners. Biochemistry and Cell Biology.
• Truitt, L., Freywald, T., DeCoteau, J., Sharfe, N. and Freywald A. (2010) The EphB6 receptor co-operates with c-Cbl to regulate the behaviour of breast cancer cells, Cancer Research.