Cannabinoid CB2 Agonists for Treatment of Breast Cancer Induced Bone Pain

摘要： 乳腺癌是北美各种族女性中最常见的恶性肿瘤，是 女性死亡的第二大原因(DHHS、CDC和NCI；2014)，NIH的总体估计成本 2011年对美国的直接医疗费用超过2000亿美元，其中887亿美元。世界卫生组织 预测到2020年，全球癌症病例将增加到1500万新病例。在晚期，骨骼 转移会导致丧失行动能力的疼痛，在75%-90%的癌症患者中表现突出。治疗的一线治疗 骨癌疼痛包括Mu阿片受体激动剂。众所周知，阿片类药物会产生有害的副作用 对癌症患者的影响包括严重嗜睡、便秘等，但最近已有研究表明 (临床和临床前)以增加骨丢失和骨折的风险。此外，持续的阿片类药物有 表现出增加包括乳腺癌在内的不同癌症的增殖和转移的倾向 癌症。 来自我们实验室和其他实验室的数据表明，大麻类CB2激动剂可能在 缓解骨癌疼痛和骨质流失。选择性CB2激动剂显著抑制骨癌疼痛，同时 不会产生CB1激动剂或麻醉剂所见的精神或兴奋作用。最近的报告和 来自我们实验室的数据已经确定CB2激动剂可以显著减少滥用药物的自我给药 包括可卡因和毒品。增加内源性大麻素(MAGL抑制增加2- 花生四烯基甘油-2AG可调节骨量，减少伤害性因子，发挥协同作用 使用吗啡抑制癌症诱导的骨痛(CIBP)和抑制肿瘤增殖。 我们使用小鼠骨癌模型的初步研究表明，MAGL抑制和CB2 受体激活通过调节核因子-κB抑制促炎细胞因子/趋化因子。 已知内源性CB2系统在骨癌疼痛/炎症中的作用，以及是否激活 内源性大麻素(ECB)系统在给予Mu阿片类药物的同时，将显著帮助骨癌患者。 目前还没有研究MAGL抑制剂或CB2激动剂与MU协同作用的研究。 阿片类激动剂对癌痛、骨质疏松症、肿瘤增殖、或减轻阿片类药物不良副作用的作用 效果。我们在骨癌疼痛特征方面的进展导致了12项直接的同行评议 出版物和初步数据进一步支持MAGL抑制和骨中CB2受体激活的研究 癌痛。我们的初步数据表明：1)可复制的同基因乳房诱发的骨癌 模型代表临床状态，2)MAG脂肪酶抑制导致2AG升高，显著 减轻癌症引起的疼痛，3)外源性和内源性CB2激动剂减轻骨丢失，4) 持续的吗啡本身就会增加骨骼降解和细胞因子，5)CB2激动剂和MAGL抑制剂 减少核因子-kB信号，抑制几种促炎细胞因子/趋化因子，同时恢复 乳腺癌细胞的凋亡，6)CIBP与吗啡和CB2激动剂的协同抑制，以及7)CB2 无副作用的激动剂。因此，MAG脂肪酶抑制剂与吗啡联合使用可能是 协同缓解骨癌疼痛，在保持骨量的同时抑制乳腺癌的增殖。 回应最近题为“发展治疗方法”的建议书(RFA PA-15-188) 内源性大麻素系统治疗疼痛的潜力“和我们的初步发现使我们 假设MAG脂肪酶抑制和/或CB2受体激活与Mu阿片类药物相结合 激动剂对小鼠乳房致痛行为的协同抑制作用 骨癌疼痛，同时减轻阿片类药物引起的骨丢失。从机械上讲，2AG和CB2 激动剂通过CB2受体发挥作用，抑制常见的转录因子NF-κB，调节 细胞因子/趋化因子。我们建议使用行为、生化、免疫和分子策略来 在吗啡存在的情况下测试MAGL抑制剂和/或CB2激动剂(标准临床护理)是否将是一种 乳房诱发骨癌疼痛的有益疗法。这一假设将通过以下目标进行检验 使用我们的CIBP同基因(非免疫受损)小鼠模型： 目的1.确定MAG脂肪酶抑制是否减轻乳腺癌引起的骨痛和/或 改变骨吸收和重塑。 目的2.探讨MAG脂肪酶抑制和CB2受体激活是否减轻乳腺癌诱导 骨痛通过共同的转录因子抑制伤害性细胞因子/趋化因子。 目的3.确定MAGL抑制剂以及CB2和Mu阿片受体的激活是否导致 协同抑制乳腺癌引起的骨痛，同时减少骨丢失。 这些研究将导致迫切需要的新疗法，并可能适用于其他转移性癌症， 包括肺和前列腺。

Abstract: Breast cancer is the most frequent malignant tumor of women of all races in North America and is the second leading cause of death among women (DHHS, CDC, & NCI; 2014) with an overall NIH estimate costs to the U.S. over $200 billion with $88.7 billion in direct medical costs in 2011. The World Health Organization predicts that global cases of cancer will rise to 15 million new cases by 2020. In advanced stages, skeletal metastasis causes incapacitating pain and is prominent in 75–90% of cancer patients. First line therapy to treat bone cancer pain includes mu opioid receptor agonists. Opioids are well known for producing unwanted side effects in cancer patients including severe somnolence, constipation, etc. but recently have been shown (clinical and preclinical) to enhance the risk of bone loss and fracture. In addition, sustained opioids have demonstrated a propensity for increasing proliferation and migration of different cancers including breast cancer. Data from our laboratory, and others, suggest that cannabinoid CB2 agonists may be effective in alleviating bone cancer pain and bone loss. Selective CB2 agonists significantly inhibit bone cancer pain while NOT resulting in the psychotropic or euphoric effects seen with CB1 agonists or narcotics. Recent reports and data from our lab have identified CB2 agonists as significantly reducing self-administration of drugs of abuse including cocaine and narcotics. Increasing endogenous cannabinoids (MAGL inhibition to increase 2- arachidonylglycerol - 2AG) may regulate bone mass, decrease pro-nociceptive factors and act synergistically with morphine to inhibit cancer-induced bone pain (CIBP) and attenuate tumor proliferation. Our preliminary studies using a murine bone cancer model indicate that MAGL inhibition and CB2 receptor activation inhibits proinflammatory cytokines/chemokines via regulating NF-κB. Yet, there is very little known about the endogenous CB2 system in bone cancer pain/inflammation, and whether the activation of the endocannabinoid (eCB) system, while administering mu opioids, will significantly aid bone cancer patients. There are NO studies investigating the synergistic combination of MAGL inhibitor or CB2 agonists with a mu opioid agonist on cancer pain, bone integrity, tumor proliferation, or attenuating mu opioid unwanted side effects. Our progress in characterizing bone cancer pain has resulted in twelve direct peer-reviewed publications and preliminary data to further support studies of MAGL inhibition, CB2 receptor activation in bone cancer pain. Our preliminary data demonstrate; 1) a reproducible syngeneic breast-induced bone cancer model representative of the clinical state, 2) MAGLipase inhibition resulting in increased 2AG, significantly attenuating cancer-induced pain, 3) exogenous and endogenous CB2 agonists attenuating bone loss, 4) sustained morphine alone increases bone degradation and cytokines, 5) CB2 agonists and MAGL inhibitors decrease NF-kB signaling, inhibiting several pro-inflammatory cytokines/chemokines, while reinstating apoptosis in breast cancer cells, 6) synergistic inhibition of CIBP with morphine and CB2 agonists, and 7) CB2 agonists lacking unwanted side effects. Hence, MAGLipase inhibitors in combination with morphine may be synergistic in alleviating bone cancer pain, attenuate breast cancer proliferation while maintaining bone mass. In response to the recent call for proposals (RFA PA-15-188) titled “Developing the Therapeutic Potential of the Endocannabinoid System for Pain Treatment” and our preliminary findings have led us to hypothesize that MAGLipase inhibition and/or CB2 receptor activation, in combination with a Mu opioid agonist will result in the synergistic inhibition of pain behaviors in a murine model of breast-induced bone cancer pain while attenuating bone loss seen with opioids. Mechanistically, 2AG and CB2 agonists act via the CB2 receptor to inhibit a common transcription factor, NF-κB, regulating multiple cytokines/chemokines. We propose to use behavioral, biochemical, immune and molecular strategies to test whether MAGL inhibition and/or CB2 agonist, in the presence of morphine (standard clinical care) will be a beneficial therapy for breast-induced bone cancer pain. This hypothesis will be tested by the following Aims using our syngeneic (non-immune-compromised) murine model of CIBP: Aim 1. Determine whether the inhibition of MAGLipase attenuates breast cancer-induced bone pain and/or alter bone resorption and remodeling. Aim 2. Explore whether MAGLipase inhibition and CB2 receptor activation attenuates breast cancer-induced bone pain by inhibiting pronociceptive cytokines/chemokines via a common transcription factor. Aim 3. Determine whether a MAGL inhibitor and the activation of the CB2 and Mu opioid receptors result in the synergistic inhibition of breast cancer-induced bone pain while reducing bone loss. These studies will lead to urgently needed new treatments and may likely apply to other metastatic cancers, including lung and prostate.