Pancreatic ductal adenocarcinoma (PDAC) is probably the most aggressive form of cancer known, with the lowest overall 5-year survival rate. Since PDAC is extremely resistant to conventional chemotherapies there is a desperate need to identify new molecular targets. Protein Kinase D (PKD) previously was recognized as a kinase overexpressed in pancreatic cancer and was shown to increase cell proliferation and prevent apoptosis in pancreatic cancer cell lines. Many of the signaling pathways regulating these processes in PDAC are currently investigated to develop molecular therapeutics. However, to date, targeting many of the involved signaling molecules failed to be effective in clinical trials. The generation of reactive oxygen species (ROS) either in response to K-ras mutations or as a consequence of chronic pancreatitis has been implicated as a crucial step in the development of PDAC. We have shown previously that PKD is a sensor for oxidative stress and our preliminary data suggests that ROS-activated PKD is a key player in transforming signaling cascades in pancreatic cancer. An additional feature of PDACs is that they are highly resistant to common chemotherapeutic agents. Our preliminary data further suggests that PKD may also be implicated in mediating resistance to common chemotherapeutics. Therefore, it is our hypothesis that PKD plays an crucial role in relaying reactive oxygen species (ROS)- and K-ras-mediated signaling, resulting in pancreatic cancer cell transformation. We further hypothesize that PKD, activated by this pathway actively contributes to resistance to chemotherapeutics by inhibiting apoptotic pathways. To test this we will: Assess the role of ROS-activated PKD in transformed signaling in PDAC cells (Aim 1); Determine if K-ras or ROS-activated PKD contributes to chemotherapeutica-resistance in PDAC (Aim 2); and Evaluate the Potential role of oxidative stress-activated PKD is an oncogenic marker for pancreatic cancer (Aim 3).
Pancreatic cancer cells are highly proliferative and resistant to most of the conventional chemotherapeutic drugs. Therefore, to effectively use chemotherapy to prevent pancreatic cancer from spreading, there is a dire need to identify new molecular targets, mediating both tumor cell transformation and resistance to chemotherapeutics. We propose that Protein Kinase D (PKD) is one of these key proteins because PKD in pancreatic cancer cells is activated by K-ras and oxidative stress, and it leads to activation of signaling events regulating cell survival, proliferation and resistance to chemotherapy. ? ? ?
