Award Title: Deciphering the role of the CCR7/CCL21 chemokine axis in ovarian cancer
Funder: Cancer Research UK

Abstract: Background: Ovarian cancer (OC) is the deadliest gynaecological malignancy- most patients die within 5 years of diagnosis. New insights into pathogenesis of OC to guide the development of novel therapies are crucial. Chemokines are small cytokines with a defining and conserved cysteine motif which are essential for regulating leukocyte migration, and they form an important part of OC tumour microenvironment.  My preliminary data suggested that the most highly expressed chemokine in OC ascites was CCL21. Moreover, high CCL21 (defined as above median expression levels) was significantly associated with poorer survival (Hazard Ratio=2.4, 95%CI 1.28-5.8, p=0.013, log-rank test).  Aims: The contribution of CCL21 to pathogenesis in OC has not previously been evaluated. CCL21 is a key regulator of CCR7+ dendritic cells (DCs) and naïve T cells. Specifically, DCs require CCL21 to exit tissues and enter lymph nodes for antigen presentation.  The aim of this project to evaluate the effects of the chemokine CCL21 on anti-tumoural responses in OC. My hypothesis is that overexpression of CCL21 induces an immunotolerant tumour microenvironment and leads to poorer survival in OC.  Methods: I will first evaluate the expression of CCL21 and its receptor CCR7 in primary tumours and metastases, and their associations with immune cell infiltration, in human OC. Moreover, the ability of ascites with high versus low levels of CCL21 to activate DCs and T cells will be compared. Secondly, I will modify an immunocompetent transplantable murine model of OC (ID8 Trp53-/-), with TP53 deletion consistent with human high-grade serous ovarian carcinoma (the commonest histological OC subtype; ~80-90%). To mimic the elevated ascites CCL21 observed, ID8 Trp53-/- will be transduced with CCL21 and/or ovalbumin, and their influence on tumour-immune microenvironment, cancer progression and survival will be assessed. Thirdly, the relatively ability of adoptively transferred murine CCR7+ DCs to migrate to lymph nodes and OVA-specific T cells to mount adaptive responses will be evaluated.  How the results will be used: This pre-clinical study will evaluate CCL21 expression in human tumours and its direct effects on immune cells. I will also modify a new immunocompetent transplantable murine model of OC to mimic the elevated CCL21 observed. Using this new model, I will evaluate the specific effects of CCL21 in OC.  If my hypothesis is correct, it would suggest a novel mechanism of tumour immune evasion in OC, and alternative strategies would be needed to promote antigen presentation and anti-cancer immune responses for improving outcomes of OC.

Lay Abstract: Background: Ovarian cancer (OC) is the deadliest gynaecological malignancy- most patients die within 5 years of diagnosis. New insights into pathogenesis of OC to guide the development of novel therapies are crucial. Chemokines are small cytokines with a defining and conserved cysteine motif which are essential for regulating leukocyte migration, and they form an important part of OC tumour microenvironment.  My preliminary data suggested that the most highly expressed chemokine in OC ascites was CCL21. Moreover, high CCL21 (defined as above median expression levels) was significantly associated with poorer survival (Hazard Ratio=2.4, 95%CI 1.28-5.8, p=0.013, log-rank test).  Aims: The contribution of CCL21 to pathogenesis in OC has not previously been evaluated. CCL21 is a key regulator of CCR7+ dendritic cells (DCs) and naïve T cells. Specifically, DCs require CCL21 to exit tissues and enter lymph nodes for antigen presentation.  The aim of this project to evaluate the effects of the chemokine CCL21 on anti-tumoural responses in OC. My hypothesis is that overexpression of CCL21 induces an immunotolerant tumour microenvironment and leads to poorer survival in OC.  Methods: I will first evaluate the expression of CCL21 and its receptor CCR7 in primary tumours and metastases, and their associations with immune cell infiltration, in human OC. Moreover, the ability of ascites with high versus low levels of CCL21 to activate DCs and T cells will be compared. Secondly, I will modify an immunocompetent transplantable murine model of OC (ID8 Trp53-/-), with TP53 deletion consistent with human high-grade serous ovarian carcinoma (the commonest histological OC subtype; ~80-90%). To mimic the elevated ascites CCL21 observed, ID8 Trp53-/- will be transduced with CCL21 and/or ovalbumin, and their influence on tumour-immune microenvironment, cancer progression and survival will be assessed. Thirdly, the relatively ability of adoptively transferred murine CCR7+ DCs to migrate to lymph nodes and OVA-specific T cells to mount adaptive responses will be evaluated.  How the results will be used: This pre-clinical study will evaluate CCL21 expression in human tumours and its direct effects on immune cells. I will also modify a new immunocompetent transplantable murine model of OC to mimic the elevated CCL21 observed. Using this new model, I will evaluate the specific effects of CCL21 in OC.  If my hypothesis is correct, it would suggest a novel mechanism of tumour immune evasion in OC, and alternative strategies would be needed to promote antigen presentation and anti-cancer immune responses for improving outcomes of OC.

Research Activity Codes: 2.1 BIOLOGICAL AND ENDOGENOUS FACTORS
Health Categories: CANCER AND NEOPLASMS