The overall goal of this application is to validate Lysophosphatidic Acid Acyltransferase-beta (LPAAT-?) as a contributor to tumorigenesis and to identify small molecule inhibitors of LPAAT-? as novel antitumor agents for the treatment of cancer. LPAAT-? is a critical enzyme that converts Lysophosphatidic Acid (LPA) to Phosphatidic Acid (PA), a cofactor needed for the full activation of several signaling proteins such as c-Raf, BRAF, PKC-zeta and mTOR that play pivotal roles in malignant transformation and tumor survival. Furthermore, the LPAAT-? generated PA has been implicated in the regulation of proliferation and survival of cancer cells. We have shown in preliminary data that LPAAT? is upregulated in various cancers. We have shown that LPAAT-b can enhance Ras-mediated transformation. We have also shown that first generation LPAAT? inhibitors inhibit tumor cell proliferation in vitro and tumor growth in vivo. Our hypothesis is that: LPAAT-? regulates the growth and survival of human cancer cells and that inhibition of this enzyme is an effective therapeutic strategy. To test this hypothesis we will pursue 3 Aims.
In Aim 1 we will determine if LPAAT-? possesses independent transforming activity and/or can collaborate with other onco-proteins in enhancing malignant transformation. Our approach will be to construct mammalian expression vectors, to over-express LPAAT-? in untransformed immortalized cell lines, and to test the oncogenic potential of LPAAT- ? in transformation assays in vitro and tumorigenic assays in immunodeficient mice in vivo.
In Aim 2, we will determine whether LPAAT-? is required for, and/or cooperates with, RalGDS/RalA/B, Raf-1/Mek1/2 or PI3K/Akt pathways to transform immortalized human primary epithelial cells. Two approaches will be used in this aim, one using Ras effector loop mutants that selectively activate each of the 3 pathways in the absence or presence of LPAAT-? siRNA. The other approach will directly express Raf-1, PI3K and Ral and determine which of these effectors can be blocked with an LPAAT-? siRNA.
In Aim 3, we will use high throughput screening and chemistry lead optimization to identify potent and selective LPAAT-? inhibitors as novel anticancer drugs. The proposed studies will further validate LPAAT-? as a target and identify inhibitors of this enzyme as novel anticancer drugs. Therefore, this proposal advances the mission of the agency to translate our understanding of signaling molecules into new therapies.

Public Health Relevance

The proposed studies will further validate LPAAT-? as a therapeutic target and identify inhibitors of this enzyme as novel anticancer drugs for the treatment of ovarian, pancreatic and other cancers. Therefore, this proposal advances the mission of the agency to translate our understanding of signaling molecules into new therapies.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA131400-05
Application #
8471661
Study Section
Drug Discovery and Molecular Pharmacology Study Section (DMP)
Program Officer
Yassin, Rihab R,
Project Start
2009-07-01
Project End
2014-05-31
Budget Start
2013-06-01
Budget End
2014-05-31
Support Year
5
Fiscal Year
2013
Total Cost
$315,962
Indirect Cost
$126,763
Name
H. Lee Moffitt Cancer Center & Research Institute
Department
Type
DUNS #
139301956
City
Tampa
State
FL
Country
United States
Zip Code
33612
Blaskovich, Michelle A; Yendluri, Vimala; Lawrence, Harshani R et al. (2013) Lysophosphatidic acid acyltransferase beta regulates mTOR signaling. PLoS One 8:e78632
Patel, Manish; Hoffe, Sarah; Malafa, Mokenge et al. (2011) Neoadjuvant GTX chemotherapy and IMRT-based chemoradiation for borderline resectable pancreatic cancer. J Surg Oncol 104:155-61