UVM Theses and Dissertations
Format:
Print
Author:
Westbom, Catherine M.
Title:
Dept./Program:
Pathology
Year:
2014
Degree:
M.S.
Abstract:
Malignant Mesothelioma (MM) is a devastating tumor of mesothelial cells caused by exposure to asbestos with no effective therapeutic approach. Inflammation plays an important role in MM tumor development. The goal of the present study was to better understand the mechanisms behind development and therapy of MM with special focus on components of the inflammation-inflammasome relationship. We have previously shown that asbestos can prime and activate NLRP3 (Nod-like Receptor protein 3) inflammasomes in mesothelial cells, however, the mechanisms behind this are unknown. In Aim 1, using telomerase-immortalized human peritoneal mesothelial cells (LP9), we demonstrated that asbestos-induced activation of NLRP3 is an oxidant-and actin polymerization-dependent· process. In addition, with the use of specific inhibitors we showed that two signaling pathways, cAMP response element binding protein (CREB) and NF-[kappa]B, play important roles in this process. Lysosomal degradation, KCI efflux and ATP receptors did not playa significant role.
In conclusion, our findings from Aim 1 demonstrated that asbestos-induced inflammasome activation in mesothelial cells is multifaceted. This information in the future· could possibly be implimented in manipulating certain biomarkers of asbestos exposure that may lead to MM.
It is well known that activation of NLRP3 increases caspase-1 as well as IL-1[beta] expression and activity in many cell types including MM cells. Caspase-1 has been shown to be an initiator of a special form of inflammatory cell death termed pyroptosis, while IL-1[beta] is a pro-inflammatory cytokine that has -been shown to increase chemotherapeutic resistance in some cancers. In Aim 2, we manipulated the NLRP3 inflammasome with the goal of designing a possible combination therapy for MM. We hypothesized that we could increase NLRP3 activation, thereby caspase-l activity, through chemotherapeutic drug treatment to increase pyroptotic cell death. Additionally, we used IL-1 receptor blocker (Anakinra) to block IL-1[beta] function, thus attenuating proinflammatory responses and IL-1[beta]-induced cell death resistance.
Our findings from Aim 2 show that the chemotherapeutic drugs prime and activate NLRP3 inflammasome in mesothelioma cell lines. In addition, we show that cisplatin in combination with anakinra had better effect on MM tumor reduction in xenograft mouse model than cisplatin alone. Findings from this Aim hold potential for developing future combination therapy for MM patients.
In conclusion, our findings from Aim 1 demonstrated that asbestos-induced inflammasome activation in mesothelial cells is multifaceted. This information in the future· could possibly be implimented in manipulating certain biomarkers of asbestos exposure that may lead to MM.
It is well known that activation of NLRP3 increases caspase-1 as well as IL-1[beta] expression and activity in many cell types including MM cells. Caspase-1 has been shown to be an initiator of a special form of inflammatory cell death termed pyroptosis, while IL-1[beta] is a pro-inflammatory cytokine that has -been shown to increase chemotherapeutic resistance in some cancers. In Aim 2, we manipulated the NLRP3 inflammasome with the goal of designing a possible combination therapy for MM. We hypothesized that we could increase NLRP3 activation, thereby caspase-l activity, through chemotherapeutic drug treatment to increase pyroptotic cell death. Additionally, we used IL-1 receptor blocker (Anakinra) to block IL-1[beta] function, thus attenuating proinflammatory responses and IL-1[beta]-induced cell death resistance.
Our findings from Aim 2 show that the chemotherapeutic drugs prime and activate NLRP3 inflammasome in mesothelioma cell lines. In addition, we show that cisplatin in combination with anakinra had better effect on MM tumor reduction in xenograft mouse model than cisplatin alone. Findings from this Aim hold potential for developing future combination therapy for MM patients.