Development of therapeutic monoclonal antibody to the bioactive lipid lysophospha

描述（由申请人提供）：由于卵巢癌在诊断时处于晚期，并且对标准治疗的获得性耐药发生率高，因此卵巢癌与较差的总生存率相关。确定卵巢癌进展的主要决定因素和开发更有效的治疗方法仍然具有挑战性。溶血磷脂酸（LPA）与卵巢癌生物学的多个方面有关，包括卵巢上皮的恶性转化、肿瘤的进展和转移。在卵巢肿瘤发生过程中，LPA受体谱变化显著，其中两种LPA2和LPA3的异常过表达与病理从良性到恶性阶段的过渡有关。LPA诱导VEGF上调、金属蛋白酶（MMP）的激活、生长因子受体的过度表达以及促血管生成和促转移细胞因子如白细胞介素-8 （IL-8）和白细胞介素-6 （IL-6）的产生。LPA不仅调节肿瘤细胞反应，还影响肿瘤微环境中癌细胞、基质、血管和细胞外基质组分之间的细胞和分子间的串扰。LPA在早期和晚期疾病患者的血清和腹水中升高。基于这些证据，LPA及其信号网络为卵巢癌治疗中合理的药物发现提供了有吸引力的分子和细胞靶点。我们已经开发出一种人源化单克隆抗体，专门识别LPA，命名为LT3015，并中和脂质对其同源gpcr的生物作用。我们假设我们的抗LPA抗体可以作为分子海绵选择性地吸收LPA，从而降低肿瘤微环境中这种致瘤性、促血管生成和转移性药物的有效细胞外水平。预计中和LPA将导致肿瘤重量和转移潜力的减少，并阻断新生血管的形成，否则将为生长的肿瘤提供营养。我们还假设LPA保护细胞免于凋亡的能力可以被抗LPA单抗逆转，从而提高标准促凋亡化疗药物的疗效。对小鼠抗lpa抗体Lpathomab的初步研究表明，在使用卵巢细胞系SKOV3进行的一系列相关体外试验中，Lpathomab显示出了有效性。Lpathomab阻断LPA触发的肿瘤细胞迁移和侵袭，减少肿瘤条件介质中细胞因子的释放，阻断LPA介导的对化疗药物紫杉醇触发的细胞凋亡的保护。更重要的是，Lpathomab延缓了原位放置的SKOV3肿瘤细胞的进展，减少了两种经典血管生成模型（Matrigel塞和脉膜新生血管模型）中的新生血管形成，并在B16-F10黑色素瘤转移模型中显示出初步的抗转移活性。在这个项目中，我们打算证明人源化抗lpa单抗（LT3015）单独或与标准化疗药物紫杉醇（Taxol）联合在人卵巢癌（SKOV3）小鼠模型中的疗效。我们将通过建立完善的LPA2受体过表达- skov3转移模型，确定LT3015抑制卵巢癌进展和卵巢肿瘤转移的最佳给药方案。在LT3015商业化的过程中，我们将进行毒理学和药代动力学研究，以确定LT3015作为临床候选药物的适用性。鉴于这些结果，我们假设基于抗LPA抗体的LPA中和可能通过阻断卵巢癌细胞或肿瘤微环境产生的LPA的促生长、血管生成和转移作用，提供了增强当前卵巢癌治疗疗效的潜力。公共卫生相关性：癌症是一种毁灭性的疾病，是美国死亡率第二高的疾病。正如2007年最新癌症趋势报告所述，肝癌、胰腺癌、肾癌、甲状腺癌、脑癌、膀胱癌和皮肤黑色素瘤等癌症的发病率，以及非霍奇金淋巴瘤、白血病、骨髓瘤和儿童癌症的新病例，在过去几年继续上升。首次诊断时的疾病状态较晚、对标准治疗的抵抗、复发病例以及最后的肿瘤转移是癌症患者治疗中出现的主要问题。特别是，一旦疾病转移，由于缺乏有效的治疗，生存率显著下降。因此，迫切需要新的抗癌疗法，以提高生活质量，并提供潜在的治愈方法。因此，发现癌症进展的主要决定因素以开发更有效的治疗方法对社会至关重要。

DESCRIPTION (provided by applicant): Ovarian cancer is associated with a poor overall survival due to the advanced stage of the disease at the time of diagnosis and the high incidence of acquired resistance to standard treatments. Identification of the major determinants of ovarian cancer progression and the development of more efficacious treatments still remain challenging. Lysophosphatidic acid (LPA) has been associated with multiple aspects of ovarian cancer biology including malignant transformation of ovarian epithelium, tumor progression and metastasis. In ovarian tumorigenesis, LPA receptors profiling changes dramatically and the aberrant overexpression of two of those ones, LPA2 and LPA3, is associated to the passage from the benign to the malignant stage of the pathology. LPA induces VEGF upregulation, activation of metalloproteinases (MMP), overexpression of growth factor receptors, and production of both pro-angiogenic and pro-metastatic cytokines such as interleukin-8 (IL-8) and interleukin-6 (IL-6). LPA not only modulates tumor cell responses but also influences cellular and molecular cross- talk among cancer cells, stroma, vascular and extracellular matrix components present in the tumor microenvironment. LPA is elevated in sera and ascites fluid of patients with early and late stage disease. Based on this evidence, LPA and its signaling network represent attractive molecular and cellular targets for rational drug discovery in the treatment of ovarian cancer. We have developed a humanized monoclonal antibody that specifically recognizes LPA, designated as LT3015, and neutralizes biological actions of the lipids on its cognate GPCRs. We hypothesize that our anti-LPA antibody could be used as a molecular sponge to selectively absorb LPA, thus lowering the effective extracellular levels of this tumorigenic, pro-angiogenic and metastatic agent in the tumor microenvironment. It is anticipated that neutralizing LPA would result in the reduction of tumor weights and metastatic potential as well as blocking the neovascularization that would otherwise feed the growing tumor. We also hypothesize that the ability of LPA to protect cells from apoptosis could be reversed by the anti-LPA mAb, thus increasing the efficacy of standard pro-apoptotic chemotherapeutic agents. Preliminary studies with the murine anti-LPA antibody, Lpathomab, have shown efficacy tested in a panel of relevant in vitro assays using the ovarian cell line SKOV3. Lpathomab blocked tumor cell migration and invasion triggered by LPA, reduced cytokines release in tumor conditioned media, and blocked LPA mediated protection from apoptosis triggered by the chemotherapeutic drug, taxol. More importantly, Lpathomab retarded the progression of orthotopically placed SKOV3 tumor cells, reduced neovascularization in two classical angiogenic models (Matrigel plug and choroid neovascularization models) and showed preliminary anti-metastatic activity when tested in the B16-F10 melanoma metastasis model. For this proposal, we intend to demonstrate the efficacy of the humanized anti-LPA mAb, designated as LT3015, alone and in combination with the standard chemotherapeutic agent, Taxol, in a murine model of human ovarian cancer (SKOV3). We will determine the optimal dosing regimen for LT3015 to inhibit ovarian cancer progression as well as ovarian tumor metastasis by using a well established LPA2 receptor overexpressing-SKOV3 metastasis model. In moving towards commercialization of LT3015, we will perform toxicology and pharmacokinetics studies to determine the suitability of LT3015 as a clinical drug candidate. In view of these results, we hypothesize that the anti-LPA antibody-based neutralization of LPA may offer the potential to augment the efficacy of current ovarian cancer therapy by blocking the growth-promoting, angiogenic and metastatic effects of LPA generated either by ovarian cancer cells or the tumor microenvironment. PUBLIC HEALTH RELEVANCE: Cancer is a devastating disease, with the second highest mortality in the US. As described in the Cancer Trends Report update 2007, the incidences of cancers such as liver, pancreas, kidney, thyroid, brain, bladder and skin melanoma as well as new cases of non-Hodgkin lymphoma, leukemia, myeloma, and childhood cancers have continue to rise in past years. Late state of disease at the first diagnosis, resistance to standard treatment, relapsing cases and, finally, tumor metastasis represent the major problems occurring in the treatment of cancer patients. In particular, once the disease becomes metastatic, survival rates drop significantly due to a lack of effective therapy. Thus, urgent needs exist for novel anti-cancer therapies that will improve quality of life as well as offering a potential cure. Discovering the major determinants in cancer progression for the development of more efficacious therapies is therefore extremely important to society.