K-Ras and mutated/over-expressed EGFR family members function as dominant oncogenes in non-small cell lung cancer (NSCLC). Yet, the signal pathways that mediate transformation by these oncogenes remainill- defined. Moreover, oncogenes stimulate both pro- and anti-tumorigenic signaling. In this regard, the JNK MAPKs, encoded by/n/c1, jnk2 and jnK3, are activated by growth factors and oncogenes and the literature documents both positive and negative roles for JNKs in cellular transformation. MKK4, a dual-specificity kinase activator of the JNKs, has emerged as a tumor metastasis suppressor in diverse human cancers. Consistent with this finding, our experiments with JNK1 and JNK2-deficient mice reveal increased carcinogen- induced lung tumorigenesis relative to wild-type littermates. Also, multiple human NSCLC cell lines show decreased JNK activity relative to non-transformed lung epithelial cells and transfected gain-of-function JNK1 inhibits anchorage-independent NSCLC growth. Thus, we propose that JNK1 and JNK2 function as components of a tumor suppressor pathway in lung cancer. By contrast, preliminary studies with JNK3- deficient mice reveal decreased carcinogen-induced lung tumorigenesis. In addition, JNKS mRNA and protein is expressed in NSCLC cell lines and primary tumors relative to non-transformed lung epithelial cells or uninvolved lung tissue. Thus, we hypothesize that JNKS is induced during lung cancer progression and represents a pro-tumorigenic JNK isoform. To test these hypotheses, we will complete the following specific aims.
Aim 1 : Determine the in vivo role for specific JNKs in murine lung tumorigenesis with mice lacking y'n/c1, jnk2 orjnkS. The role of specific JNKs as signal components of the host lung microenvironment regulating lung tumorigenesis will also be tested.
Aim 2 : Test the in vitro role of specific JNKs in tumor suppression or cellular transformation. Non-transformed lung epithelial cell lines expressing molecular inhibitors of the JNKs will be transduced with oncogenic K-Ras and criteria of transformation, differentiation and apoptosis will be measured. Also, NSCLC cells transduced with gain-of-function JNKs or dominant-negative JNKS will be monitored for criteria of cellular transformation.
Aim 3 : Define the mechanism(s) accounting for decreased JNK1 and JNK2 activity in NSCLC cell lines. The role of MKPs as oncogene-induced negative regulators of JNK1 and JNK2 activity will be highlighted.
Aim 4 : The activation state of JNKs and expression status of specific signaling molecules defined in Aims 1-3 will be measured in archived primary human lung tumors with IHC and quantitative RT-PCR and correlated with clinical behaviour. Completion of these specific aims will lead to a comprehensive understanding of the complex role of this family of MAP kinases in lung tumorigenesis and provide a format for exploration of the role of these kinases in other human cancers. Furthermore, a detailed understanding of the multi-faceted role of the JNK MAP kinases in lung cancer is absolutely required for rationale and precise therapeutic targeting of this pathway to combat lung cancer.
| Symonds, Jennifer M; Ohm, Angela M; Carter, Cristan J et al. (2011) Protein kinase C ? is a downstream effector of oncogenic K-ras in lung tumors. Cancer Res 71:2087-97 |
| Chen, Peila; O'Neal, Jamye F; Ebelt, Nancy D et al. (2010) Jnk2 effects on tumor development, genetic instability and replicative stress in an oncogene-driven mouse mammary tumor model. PLoS One 5:e10443 |
| Wang, Xue-Qing; Li, Howard; Van Putten, Vicki et al. (2009) Oncogenic K-Ras regulates proliferation and cell junctions in lung epithelial cells through induction of cyclooxygenase-2 and activation of metalloproteinase-9. Mol Biol Cell 20:791-800 |
| Marek, Lindsay; Ware, Kathryn E; Fritzsche, Alexa et al. (2009) Fibroblast growth factor (FGF) and FGF receptor-mediated autocrine signaling in non-small-cell lung cancer cells. Mol Pharmacol 75:196-207 |
| Heasley, Lynn E; Winn, Robert A (2008) Analysis of Wnt7a-stimulated JNK activity and cJun phosphorylation in non-small cell lung cancer cells. Methods Mol Biol 468:187-96 |
