Effects of TPA on Leukemia and Solid Tumors

描述(由申请人提供)： 目前关于12-O-十四酰佛波醇-13-乙酸酯(TPA)临床前研究的建议将： 1.鉴定和鉴定TPA和其他潜在的治疗药物的组合，这些药物在治疗髓系恶性肿瘤中可以增强分化和治疗效果，并克服对TPA诱导分化的潜在抵抗。2.验证以下假设：TPA、全反式维甲酸(ATRA)、1α，25-二羟基维生素D3或丁酸盐单独或协同作用是通过改变PKCα、PKCβ和PKC Delta的水平和转位，以及对TPA敏感的HL-60和TPA耐药的HL-525细胞PKCα、PKCβ和PKC Delta的mRNAs表达的影响来实现的。我们还将确定PKCβ和PKC Delta的选择性抑制剂以及HL-60细胞中显性负性PKC亚型的表达对这些细胞单独或与潜在的增效剂一起对TPA的分化反应的影响。此外，还将确定组成蛋白激酶C亚型过表达对TPA单独诱导耐TPA HL-525细胞分化作用的影响。3.研究TPA对人前列腺癌细胞毒作用的假说。具体地说，我们将确定TPA单独或与(A)分化药物(ATRA、1α，25-二羟基维生素D3和丁酸盐)、(B)核因子-kappaB抑制剂(Bay 11-7082)或(C)细胞毒药物(紫杉醇、紫杉醇、米托蒽醌和雌激胺)对培养的人前列腺癌细胞系增殖和凋亡的影响。我们将检验这样一种假设，即构成核因子-kappaB活性的水平决定了这些细胞对TPA诱导的细胞毒性的敏感性。将评估TPA单独或联合增效剂对前列腺癌细胞中PKCα、PKCβ和PKC Delta水平和转位的影响，以及对这些基因表达的影响。4.确定TPA单独或与其他协同作用的药物在免疫缺陷小鼠体内对人前列腺肿瘤生长的影响。血液中与抑制肿瘤生长相关的TPA水平将被测定。肿瘤生长抑制物对肿瘤增殖和凋亡的影响将被确定。

DESCRIPTION (provided by applicant): The present proposal for preclinical studies with 12-O-tetradecanoylphorbol-13-acetate (TPA) will: 1. Identify and characterize combinations of TPA and other potential therapeutic agents that may enhance differentiation and therapeutic efficacy and overcome potential resistance to TPA-induced differentiation in the treatment of myeloid malignancies. 2. Examine the hypothesis that the effects of TPA, all-trans retinoic acid (ATRA), 1 alpha,25-dihydroxyvitamin D3 or butyrate alone or as synergistic combinations are mediated through changes in the levels and translocation of PKC alpha, PKC beta and PKC delta, and on the expression of mRNAs for PKC alpha, PKC beta and PKC delta in TPA-sensitive HL-60 and TPA-resistant HL-525 cells. We will also determine the effects of selective inhibitors of PKC beta and PKC delta as well as the expression of dominant negative PKC isoforms in HL-60 cells on the differentiation response of these cells to TPA alone or together with potential synergistic agents. The effects of overexpression of constitutive PKC isoforms on the action of TPA alone to cause differentiation in TPA-resistant HL-525 cells will also be determined. 3. Study the hypothesis that TPA may have therapeutic efficacy for inducing cytotoxicity in human prostate cancer cells. Specifically, we will determine the effects of TPA alone or in combination with (a) differentiating agents (ATRA, 1alpha, 25-dihydroxyvitamin D3, and butyrate), (b) inhibitors of NF-kappaB (BAY 11-7082) or (c) cytotoxic drugs (taxol, taxotere, mitoxantrone and estramustine) on proliferation and apoptosis of cultured human prostate cancer cell lines. We will test the hypothesis that levels of constitutive NF-kappaB activity determine sensitivity of these cells to TPA-induced cytotoxicity. The effects of TPA alone or in combination with synergizers on the levels and translocation of PKC alpha PKC beta and PKC delta and on the expression of these genes in prostate cancer cells will be evaluated. 4. Determine the in vivo effects of TPA alone, or in combination with other agents that are synergistic, on the growth of human prostate tumors in immunodeficient mice. Blood levels of TPA that are associated with inhibition of tumor growth will be determined. The effect of inhibitors of tumor growth on proliferation and apoptosis in the tumors will be determined.