Grant R01CA196263

Peripherally-restricted cannabinoids for cancer and chemotherapy-induced pain

Synthetic and naturally occurring cannabinoids (CBs) have demonstrated effectiveness in numerous chronic inflammatory and neuropathic disorders in humans and in animal models. However, major impediments to the widespread use of CB-based therapies are their psychotropic side-effects, mediated by the activation of central nervous system (CNS) CB1 receptors (CB1Rs). Recently, we developed a series of synthetic peripherally-restricted CBs (PRCBs), and demonstrated potent reversible and repeated suppression of chronic inflammatory and neuropathic pain symptoms in the absence of CNS-mediated side effects. The therapeutic utility of PRCBs may include many other indications where brain-permeant CBs have been shown to be effective. Cancer pain and chemotherapy-induced neuropathy are particularly attractive targets since brain-permeant CBs possess antitumorigenic properties and have been shown to ameliorate the pain symptoms of cancer and chemotherapy-induced neuropathies mainly by peripheral mechanisms. Therefore, this proposal focuses on establishing effectiveness and mechanisms of action of PRCBs against: a) human oral carcinoma proliferation, b) oral carcinoma-induced pain, and c) chemotherapy-induced peripheral neuropathies (CIPNs). We will achieve these aims through the use of innovative and validated operant assays that provide a measure of cerebral processing and orofacial function in mouse oral cancer and rat CIPN models. Gender differences in cancer and CIPN pain sensitivity and their responsiveness to PRCBs will be determined. To further characterize PRCBs we will perform pharmacokinetic studies and determine their receptor targets with tissue-specific transgenic mice. To assess potential off-target actions and peripheral side effects of PRCBs we will use a suite of invasive and non-invasive physiological tools. We will also assess the potential development of tolerance to PRCBs after chronic administration and determine if pre-treatment with PRCBs may actually prevent the onset and maintenance of CIPN symptoms. Successful completion of the proposed studies would allow us to translate pre- clinical findings to a clinical trial; this work would improve outcome for cancer patients.