K-Ras-induced lung cancer is a very common disease, for which there are currently no effective therapies. Because therapy directly targeting the activity of oncogenic Ras has been unsuccessful, a different approach for novel therapy design is to identify critical Ras downstream oncogenic targets. Given that oncogenic Ras proteins activate the transcription factor NF-κB, and the importance of NF-κB in oncogenesis, we hypothesized that NF-κB would be an important K-Ras target in lung cancer. To address this hypothesis, we generated a NF-κB-EGFP reporter mouse model of K-Ras-induced lung cancer and determined that K-Ras activates NF-κB in lung tumors in situ. Furthermore, a mouse model was generated where activation of oncogenic K-Ras in lung cells was coupled with inactivation of the NF-κB subunit p65/RelA. In this model, deletion of p65/RelA reduces the number of K-Ras-induced lung tumors both in the presence and in the absence of the tumor suppressor p53. Lung tumors with loss of p65/RelA have higher numbers of apoptotic cells, reduced spread, and lower grade. Using lung cell lines expressing oncogenic K-Ras, we show that NF-κB is activated in these cells in a K-Ras-dependent manner and that NF-κB activation by K-Ras requires inhibitor of κB kinase β (IKKβ) kinase activity. Taken together, these results show the importance of the NF-κB subunit p65/RelA in K-Ras-induced lung transformation and identify IKKβ as a potential therapeutic target for K-Ras-induced lung cancer. Cancer Res; 70(9); 3537-46. ©2010 AACR.

Background: Akt is a key regulator of mTORC1, functioning through phosphorylation of TSC2 and PRAS40. Results: Downstream of Akt, IKK␣ directly phosphorylates mTOR to drive mTORC1 activation. Knock-out of IKK␣ suppresses mTORC1 activation in vivo. Conclusion: IKK␣ is important in the activation of mTORC1 via direct phosphorylation. Significance: Results provide insight into the ability of Akt to promote mTORC1 activity.

Cholinergic muscarinic systems have been shown to influence dopaminergic function in the central nervous system. In addition, previous studies of benztropine analogs that inhibit dopamine uptake and show antagonism at muscarinic receptors show these drugs to be less effective than cocaine in producing its various prototypic effects such as locomotor stimulation. Because previous pharmacological studies on these topics have used nonselective M 1 antagonists, we examined the interactions of preferential M 1 muscarinic antagonists and cocaine. Dose-dependent increases in extracellular levels of dopamine in selected brain areas, the nucleus accumbens (NAc) shell and core, and the prefrontal cortex, were produced by cocaine but not by the preferential M 1 antagonists telenzepine and trihexyphenidyl. When administered with cocaine, however, both M 1 antagonists dose-dependently increased the effects of cocaine on dopamine in the NAc shell, and these effects were selective in that they were not obtained in the NAc core or in the prefrontal cortex. Telenzepine also increased locomotor activity, although the effect was small compared with that of cocaine. The locomotor stimulant effects of trihexyphenidyl, in contrast, approached those of cocaine. Telenzepine attenuated, whereas trihexyphenidyl enhanced the locomotor stimulant effects of cocaine, with neither drug facilitating cocaine-induced stereotypy. The present results indicate that preferential antagonist effects at muscarinic M 1 receptors do not uniformly alter all of the effects of cocaine, nor do they explain the differences in effects of cocaine and benztropine analogs, and that the alterations in dopamine levels in the NAc shell do not predict the behavioral effects of the interactions with cocaine.Both clinical and preclinical data support the existence of extensive interactions between the dopaminergic and cholinergic muscarinic systems in various central nervous system functions and disease, including Parkinson's disease, schizophrenia, and cocaine dependence. Preclinical studies have shown that the administration of muscarinic M 1 receptor agonists and antagonists increase or decrease, respectively, levels of extracellular DA in striatal and cortical areas (Xu et al., 1989;De Klippel et al., 1993;Gronier et al., 2000). Cocaine self-administration by rats increases concentrations of acetylcholine in the NAc shell (Mark et al., 1999) and increases acetylcholine turnover rates in several brain regions (Smith et al., 2004a,b) compared with passively administered cocaine. Changes in acetylcholine resulting from cocaine administration seem to be due to activation of cholinergic interneurons in the NAc and dorsal striatum (Berlanga et al., 2003), and cocaine treatment can produce an up-regulation of muscarinic binding at 1 day, but not 30 min after treatment (Macêdo et al., 2001). Finally, cholinergic lesions of posterior nucleus accumbens and ventral pallidal regions produced a leftward shift of the cocaine dose-effect curve in rats trained to self-adm...

Drugs that inhibit dopamine (DA) reuptake through actions at the dopamine transporter (DAT) have been proposed as candidates for development as pharmacotherapies for cocaine abuse. Accordingly, it is important to understand the potential pharmacological interactions of cocaine with other drugs acting at the DAT. Effects of combinations of cocaine with a cocaine analog, 2␤-carbomethoxy-3␤-(4-fluorophenyl)tropane (WIN 35,428), were compared quantitatively with the combinations of cocaine with the N-butyl,4Ј,4Љ-diF benztropine analog, 3-(bis(4-fluorophenyl)methoxy)-8-butyl-8-azabicyclo[3.2.1]octane (JHW 007), to determine whether their effects on DA levels in the shell of the nucleus accumbens (NAC) in mice differed. Each of the drugs alone produced dose-related elevations in NAC DA levels. In contrast to the other drugs, JHW 007 was less effective, producing maximal effects that approached 400% of control versus ϳ700% with the other drugs. In addition, the JHW 007 dose-effect curve was not as steep as those for cocaine and WIN 35,428. Combinations of cocaine with its analog, WIN 35,428, were most often greater than those predicted based on dose additivity. In contrast, combinations of cocaine with JHW 007 were most often subadditive. This outcome is consistent with recent studies suggesting that structurally divergent DA uptake inhibitors bind to different domains of the DAT, which can result in different DAT conformations. The conformational changes occurring with JHW 007 binding may result in functional outcomes that alter its abuse liability and its effects in combination with cocaine.