Tappel Al
Department of Food Science and Technology, University of California, Davis, CA 95616, USA.
Med Hypotheses. 2005;64(6):1170-2. doi: 10.1016/j.mehy.2004.11.039.
Lysosomes, lysosomal enzymes and oxidant processes are known to be involved in cancer processes. The prostasomes contain proteins and enzymes that would constitute pathways for the hydrolysis of proteins and peptides. However, integrated biochemical and cell biology studies are necessary to understand how lysosomal enzymes and prostasomal enzymes combined with oxidant processes could initiate cancer. Most prostate cancer is likely to be initiated in the prostate duct system. The lysosomal enzymes acid phosphatase and glucosidase and prostasomal proteins and enzymes are found in human semen and therefore have come through prostate ducts. The hypothesis presented here is that the lysosomal enzymes and prostasomes are exocytosed from prostate cells into the duct system of the prostate where their hydrolytic enzymes and oxidative processes, for example, the iron from the iron-sulfur clusters of the prostasomal dehydrogenases, damage proteins and other components of cells leading to the initiation of cancer. Risk factors for prostate cancer are known to initiate activity of lysosomal enzymes and could initiate activity of prostasomal enzymes. These risk factors include: ionizing radiation, oxidative stress, environmental toxicants and dietary components including those with high fat content. Other dietary components in fruits and vegetables protect against prostate cancer and can be hypothesized as decreasing cellular output of lysosomal or protasomal enzymes or inhibiting lysosomal and prostasomal enzymes in the duct system. Measurements of multiple lysosomal and prostasomal enzyme activities and their biochemical pathways are vital to the understanding of protectors to inhibit lysosomal or prostasomal enzyme activities that might be leading to prostate cancer. Inhibitors of lysosomal and prostasomal enzymes can be investigated in cellular and biochemical systems, and these inhibitors could be used to control these enzyme activities in vivo. In situ enzyme analyses including substrates producing fluorescent products are applicable. Screening assays could be developed to detect in vivo lysosomal and prostasomal enzyme activities in semen. Lysosomal enzyme activities may be precursors to the onset of other kinds of cancer with other similar non-invasive screening techniques possible. Present knowledge encompasses mobilization of sperm when prostasomes bind to sperm in semen. A further hypothesis of this study projects that prostasomal dehydrogenases and their NADH products initiate the formation of ATP in the sperm mitochondria which activates flagellar movement. This overall hypothesis suggests protection against prostate cancer by inhibitors of lipid peroxidation including the dietary antioxidants selenium, vitamin E and lycopene and also cysteine glutathione.
已知溶酶体、溶酶体酶和氧化过程参与癌症进程。前列腺小体含有蛋白质和酶,这些物质可能构成蛋白质和肽水解的途径。然而,需要综合生化和细胞生物学研究来了解溶酶体酶和前列腺小体酶如何与氧化过程相结合从而引发癌症。大多数前列腺癌可能起源于前列腺导管系统。溶酶体酶酸性磷酸酶和葡糖苷酶以及前列腺小体蛋白质和酶存在于人类精液中,因此经过了前列腺导管。这里提出的假说是,溶酶体酶和前列腺小体从前列腺细胞中胞吐到前列腺导管系统,在那里它们的水解酶和氧化过程,例如前列腺小体脱氢酶铁硫簇中的铁,会损伤细胞的蛋白质和其他成分,从而引发癌症。已知前列腺癌的风险因素会引发溶酶体酶的活性,也可能引发前列腺小体酶的活性。这些风险因素包括:电离辐射、氧化应激、环境毒物以及饮食成分,包括高脂肪含量的成分。水果和蔬菜中的其他饮食成分可预防前列腺癌,可以推测它们能减少溶酶体或前列腺小体酶的细胞输出量,或者抑制导管系统中的溶酶体和前列腺小体酶。测量多种溶酶体和前列腺小体酶的活性及其生化途径对于理解抑制可能导致前列腺癌的溶酶体或前列腺小体酶活性的保护剂至关重要。溶酶体和前列腺小体酶的抑制剂可在细胞和生化系统中进行研究,这些抑制剂可用于在体内控制这些酶的活性。包括产生荧光产物的底物在内的原位酶分析是适用的。可以开发筛选检测方法来检测精液中体内溶酶体和前列腺小体酶的活性。溶酶体酶活性可能是其他类型癌症发病的先兆,其他类似的非侵入性筛选技术也是可行的。目前的知识包括当前列腺小体在精液中与精子结合时精子的动员。本研究的另一个假说预测,前列腺小体脱氢酶及其NADH产物会启动精子线粒体中ATP的形成,从而激活鞭毛运动。这一总体假说表明,包括饮食抗氧化剂硒、维生素E、番茄红素以及半胱氨酸谷胱甘肽在内的脂质过氧化抑制剂可预防前列腺癌。