Investigations into the roles of Histamine Receptor H1 and extracellular vesicles in ovarian cancer cell behaviour

Ovarian cancer (OC) diagnosis usually occurs very late, when metastatic spread has already started and patient’s survival is very low. One of the many soluble factors that can promote cancer metastasis is histamine, a compound involved in a plethora of physiological and pathological processes, including cancer. Indeed, activation of histamine receptor H1 (HRH1) by histamine stimulates growth of OC cells in vitro and promotes the release of extracellular vesicles (EVs) in different cell lines. EVs are heterogeneous small vesicles involved in intracellular communication, which also modulate various steps of the metastatic process. The main hypothesis of this thesis is that HRH1 mediates several cancerous behaviours associated with OC metastatic spread, by regulating EV release. The specific aims were 1) to analyse the correlation of histamine receptors gene expression with invasion and migration rates of OC cell lines in vitro and with tumour stage of OC clinical samples; 2) to study the involvement of HRH1 in different cellular behaviours associated with cancer metastasis; 3) to investigate the involvement of HRH1 in EV release and how they affect OC cell invasion in vitro. The results show that the level of HRH1 mRNA positively correlates with in vitro migration and invasion rate of OC cells lines and higher expression was found in stage IV of OC clinical samples compared to stage II/III. Low HRH1 correlates with increased disease free survival, although no correlation was found with overall survival. HRH1 expression was modulated in three OC cell lines (SKOV3, OVCAR3 and OVCAR5), via siRNA transfection, chemical activation (via histamine) or inhibition (via chlorpheniramine) and its effect on cellular behaviour was evaluated through different in vitro assays. Results showed that HRH1: 1) does not modulate gene expression of EMT-related genes; 2) does not influence adhesion of OC cells to endothelial cells; 3) reduces cell invasion through a Matrigel®️ layer and 4) reduces their movement from the edge of a simulated ‘wound’. Histamine increases the number of EVs released from SKOV3 cells and their ability to degrade a collagen substrate but did not modify EV protein contents compared to control EVs. EVs were able to rescue the reduction of invasion caused by HRH1 knockdown, while histamine failed to rescue the invasion of cells knocked down for Rab27a (a major regulator of EV production), suggesting a potential interplay between HRH1 and Rab27a in modulating EV release and cell invasion. Overall, these results suggest that HRH1, via modulation of EV biogenesis, can impair OC cells invasion and migration in vitro.

Grantor dc:publisher

Oxford Brookes University

Year dc:date

2021

Author dc:creator

• Carollo, Emanuela

Contributors dc:contributor

• Carter, David
• Brooks, Susan A

Statement dc:rights

• All rights reserved

Language dc:language

en

DOI dc:identifier

https://doi.org/10.24384/5zz6-x398

OAI identifier oai:identifier

tle:993c75b9-4085-4268-a616-ba53bc77b419:d6bd9758-527a-46cd-bfe2-c433766e8fca:1