Welshons W V, Wolf M F, Murphy C S, Jordan V C
Department of Human Oncology, University of Wisconsin Clinical Cancer Center, Madison 53792.
Mol Cell Endocrinol. 1988 Jun;57(3):169-78. doi: 10.1016/0303-7207(88)90072-x.
It has recently been reported that phenol red, a pH indicator present in most tissue culture media, is a weak estrogen that can stimulate some estrogen-sensitive cells. However, the relative impact of phenol red on various cell lines is controversial. We examined the effect of phenol red on several estrogen-responsive cell systems that we use to study estrogen action. These included estrogenic stimulation of progesterone receptor and growth in human breast cancer-derived MCF-7 cells, stimulation of growth in human breast cancer-derived T47D cells, stimulation of prolactin synthesis in primary cultures of immature rat pituitary cells, and stimulation of progesterone receptor in primary cultures of immature rat uterine cells. Estrogenic responses in MCF-7 cells were the most sensitive to the presence of phenol red, while the other three cell cultures showed lesser effects of the indicator. In addition to intrinsic differences in cell responses, there were several other factors involved. These included differences in the estrogenic activity of phenol red-containing media and phenol red itself from different commercial suppliers, and differences in the concentration of free phenol red in final media due to binding of the indicator by serum. Higher concentrations of serum reduced the impact of phenol red on estrogenic responses in primary pituitary cells. Phenol red added to rat uterine cytosol competed with estradiol for binding to the estrogen receptor (relative binding affinity (RBA) approx. 0.001), and the acidic and basic forms of the indicator showed similar activity. Some commercial phenol red samples inhibited cell growth at levels of 100 mg/l; these effects were toxic rather than antiestrogenic, because growth inhibition could not be competitively reversed by an excess of estradiol. The amount of the indicator bound to serum in the final media, the source of the phenol red and the sensitivity of different cell types to the indicator ultimately determine its influence to the response of cells in tissue culture.
最近有报道称，大多数组织培养基中存在的pH指示剂酚红是一种弱雌激素，可刺激某些雌激素敏感细胞。然而，酚红对各种细胞系的相对影响存在争议。我们研究了酚红对我们用于研究雌激素作用的几种雌激素反应性细胞系统的影响。这些包括雌激素对人乳腺癌来源的MCF-7细胞中孕激素受体的刺激和生长的影响、对人乳腺癌来源的T47D细胞生长的刺激、对未成熟大鼠垂体细胞原代培养物中催乳素合成的刺激以及对未成熟大鼠子宫细胞原代培养物中孕激素受体的刺激。MCF-7细胞中的雌激素反应对酚红的存在最为敏感，而其他三种细胞培养物显示该指示剂的影响较小。除了细胞反应的内在差异外，还涉及其他几个因素。这些包括来自不同商业供应商的含酚红培养基和酚红本身的雌激素活性差异，以及由于血清与指示剂结合导致最终培养基中游离酚红浓度的差异。较高浓度的血清降低了酚红对垂体原代细胞雌激素反应的影响。添加到大鼠子宫细胞质中的酚红与雌二醇竞争结合雌激素受体（相对结合亲和力（RBA）约为0.001），并且指示剂的酸性和碱性形式显示出相似的活性。一些商业酚红样品在100 mg/l的水平上抑制细胞生长；这些作用是毒性作用而非抗雌激素作用，因为过量的雌二醇不能竞争性逆转生长抑制。最终培养基中与血清结合的指示剂量、酚红的来源以及不同细胞类型对指示剂的敏感性最终决定了其对组织培养中细胞反应的影响。
