Identifying ethnically relevant targets for improved treatment of ER+ breast cancer in British-Black women

Primary supervisor: Kairbaan Hodivala-Dilke, Queen Mary University of London

Secondary supervisor: Anita Grigoriadis, King’s College London; Louise Jones, Queen Mary University of London

Project

Ethnic diversity and breast cancer

Relevant to the CRUK City of London Centre, East London has one of the most ethnically diverse populations in the country and this impacts on cancer outcomes. There is a need to better understand the biology of cancer in our ethnic minority population. British-Black women are disproportionately affected by more aggressive breast cancer subtypes, and they are more likely to be diagnosed at younger ages (prior to eligibility for screening) with more advanced stages of the disease (Jones et al, BMJ Open 2015). Socio-economic and cultural factors influence this, but it is clear there are also biological differences. However, the biological basis for this disparity is understudied and requires urgent attention if treatment and outcomes are to improve for these women, especially now since pembrolizumab for neoadjuvant and adjuvant treatment of triple-negative early or locally advanced breast cancer has been approved by NICE in December 2022. ER+ breast cancer represents 80% of all breast cancer cases in the UK but almost no studies on ethnic diversity influences have been published relevant to ER+ breast cancer.

Focus on the tumour microenvironment

Recent RNAseq evidence has indicated that triple negative breast cancer (TNBC) of African American women have a significantly altered immune cell landscape compared with Caucasian women with TNBC (Martini et al., Cancer Discovery 2022, Please note that we have established a collaboration to expand on these findings). The reason for this is unknown, but suggests that immunotherapies may be less likely to be effective in this population.

Reduced stromal αv-integrin subunit RNA expression and enhanced malignant cell AKT1 RNA levels have also been reported in African American TNBC compared with Caucasian women (Martini et al., Cancer Discovery 2022). The αv subunit is non-functional as a single subunit but heterodimerises to form the active transmembrane receptors αvβ3 and αvβ1. Reduced αvβ3 expression has been predicted to be functionally relevant in inhibiting leukocyte activation and migration and is thus likely to be involved in aberrant immune cell responses, whilst enhanced AKT1 signalling is important in increased malignant cell survival (Andrikopoulou et al., Breast 2020). Additional ethnically relevant effects on molecular alterations of the TME and the malignant cell compartment and how they cross regulate are unknown and could identify new targets relevant for breast cancer control in Black women.

Aligning with these studies, we have identified functional links between loss of stromal αv integrins in ER+ breast cancer and enhanced malignant cell AKT1 signalling. Briefly:

• Loss of stromal αvβ3 and αvβ5 enhances tumour growth (Reynolds et al., Nature Medicine 2002)
• Loss of αvβ3-integrin expression in the supporting cells of tumour blood vessels (mural cells and pericytes) is sufficient to increase tumour burden and relapse rates significantly in British ER+ breast cancer patients (Wong and Munoz-Felix, Cell 2020),
• Mechanistically, loss of mural cell and pericyte αvβ3-integrin alters paracrine signals that directly affect tumour cell Rho-associated kinase (ROCK) and AKT1 signaling, increasing tumour cell invasion and survival (Crosas-Molist Phys Reviews 2022; Wong and Munoz-Felix, Cell 2020). This is of particular relevance since highly effective targeted therapies exist for this pathway.
• Effects of stromal αv-integrin loss on immune cell infiltration and activation are unknown.

Together these data suggest that loss of stromal αvβ3 expression provides a model for testing the effects on immune cell activation and infiltration in breast cancer aggressiveness relevant to British-Black women.

PhD Project

This Phd will entail understanding the biological effects of reduced stromal αv-integrin expression in the control of cancer growth and metastasis and identify ethnically relevant links with breast cancer in British-Black women. The techniques to be used will span state-of-the-art spatial transcriptomics, in vitro cell invasion and metastasis assays together with in vivo validation of target pathways.

Overall, this Phd will inform new strategies for improved and ethnically relevant testing and treatment of breast cancer.

Aim 1: Identify molecular changes relevant to low stromal αvβ3 in ER+ breast cancer in British-Black women. (0-12 months)
Use Nanostring GeoMx and CosMx spatial transcriptomics/proteomics and subcellular receptor ligand interaction analysis of ER+ British-Black and Caucasian ER+ breast cancer of matched socioeconomic backgrounds (50 patients for each). Patients with low levels of stromal ?v integrin will be identified by immunostaining of breast cancer sections in proteomics analysis. Both malignant and stromal transcript signatures and molecular pathways will be discerned, and deconvolution tools used to determine alterations in cellular subtypes with a special focus on changes in immune cell infiltration and activation, and pathways relevant to tumour cell invasion.

Aim 2: Identify the molecular mechanisms of dysregulated molecular pathways discovered in Aim1. (9-24 months)
Using in vitro systems established in the home laboratories, the functional relevance of the disregulated molecular pathways will be tested in breast cancer 3D growth and invasion.

Aim 3: In vivo validation of target inhibition. (20-32 months)
In stromal αv- and β3-null mice, that are already available in house, the functional relevance of target pathway inhibition will be tested in combination with standard of care chemotherapy and immunotherapy with special attention given to immune cell migration, immune cell activation, and malignant cell invasion and survival.

Potential Research Placements

1. Anita Grigoriadis, Comprehensive Cancer Centre, King’s College London
2. Jun Wang, Barts Cancer Institute, Queen Mary University of London
3. Richard Grose, Barts Cancer Institute, Queen Mary University of London

References

1. Wong PP, Muñoz-Félix JM, Hijazi M, Kim H, Robinson SD, De Luxán-Delgado B, Rodríguez-Hernández I, Maiques O, Meng YM, Meng Q, Bodrug N, Dukinfield MS, Reynolds LE, Elia G, Clear A, Harwood C, Wang Y, Campbell JJ, Singh R, Zhang P, Schall TJ, Matchett KP, Henderson NC, Szlosarek PW, Dreger SA, Smith S, Jones JL, Gribben JG, Cutillas PR, Meier P, Sanz-Moreno V, Hodivala-Dilke KM.Cancer Burden Is Controlled by Mural Cell-β3-Integrin Regulated Crosstalk with Tumor Cells. Cell. 2020 Jun 11;181(6):1346-1363.e21. PMID: 32473126.
2. Demircioglu F, Wang J, Candido J, Costa ASH, Casado P, de Luxan Delgado B, Reynolds LE, Gomez-Escudero J, Newport E, Rajeeve V, Baker AM, Roy-Luzarraga M, Graham TA, Foster J, Wang Y, Campbell JJ, Singh R, Zhang P, Schall TJ, Balkwill FR, Sosabowski J, Cutillas PR, Frezza C, Sancho P, Hodivala-Dilke KM. Cancer associated fibroblast FAK regulates malignant cell metabolism. Nature Comm. 2020 Mar 10;11(1):1290. PMID: 32157087
3. Lechertier T, Reynolds LE, Kim H, Pedrosa AR, Gómez-Escudero J, Muñoz-Félix JM, Batista S, Dukinfield M, Demircioglu F, Wong PP, Matchett KP, Henderson NC, D’Amico G, Parsons M, Harwood C, Meier P, Hodivala-Dilke KM. Pericyte FAK negatively regulates Gas6/Axl signalling to suppress tumour angiogenesis and tumour growth. Nature Comm. 2020 Jun 4;11(1):2810. PMID: 32499572
4. Roy-Luzarraga M, Abdel-Fatah T, Reynolds LE, Clear A, Taylor JG, Gribben JG, Chan S, Jones L, Hodivala-Dilke KM. Association of Low Tumor Endothelial Cell pY397-Focal Adhesion Kinase Expression With Survival in Patients With Neoadjuvant-Treated Locally Advanced Breast Cancer. JAMA Netw Open. 2020 Oct 1;3(10):e2019304. PMID: 33107920
5. Roy-Luzarraga M, Reynolds LE, de Luxán-Delgado B, Maiques O, Wisniewski L, Newport E, Rajeeve V, Drake RJG, Gómez-Escudero J, Richards F, Weller C, Dormann C, Meng Y-M, Vermeulen PB, Saur D, Sanz-Moreno V, Wong P-P, Géraud C, Cutillas PR, Hodivala-Dilke KM.Suppression of endothelial cell FAK expression reduces pancreatic ductal adenocarcinoma metastasis after gemcitabine treatment Cancer Research 2022 May 16;82(10):1909-1925. PMID: 35350066