Toyoshima K, Valentich J D, Tchao R, Leighton J
Cancer Res. 1976 Aug;36(8):2800-6.
Rat urinary bladder carcinoma R-4909 grew readily in vitro. In areas where saturation density occurred in the cultures, occasional hemicysts were observed. A modification of technique producing "packed cultures" resulted in the appearance of greater numbers of hemicysts. Four clonal isolates of R-4909 were also studied in packed culture. Clone B formed hemicysts in abundance. Clone D produced occasional hemicysts similar to the parent stock line. No hemicysts were seen in cultures of clone A or clone C. The number of hemicysts formed by clone B in packed culture was responsive to the ratio between cell number and volume of medium, to serum concentration in the medium, and to pH of the medium. The last was of particular interest since a pH of 7.8 enhanced and a pH of 6.6 inhibited hemicyst formation. The effects were all reversible. On scanning electron microscopy, we found well-developed cell membrane structures between contiguous cells. In media with sufficient serum for hemicyst formation, the articulations between cells were prominent. With low serum concentrations, hemicysts did not form and the intercellular articulations were less distinct. We interpret the formation of hemicysts as an expression of fluid transport by epithelia, a function that requires a constellation of differentiated characteristics within cells and in their level of integrated association.
大鼠膀胱癌R - 4909在体外易于生长。在培养物中出现饱和密度的区域，偶尔会观察到半囊肿。一种产生“密集培养物”的技术改进导致出现了更多数量的半囊肿。还对R - 4909的四个克隆分离株进行了密集培养研究。克隆B大量形成半囊肿。克隆D偶尔产生与亲本系相似的半囊肿。在克隆A或克隆C的培养物中未观察到半囊肿。克隆B在密集培养中形成的半囊肿数量对细胞数量与培养基体积之比、培养基中的血清浓度以及培养基的pH值有反应。最后一点特别有趣，因为pH值为7.8时会促进半囊肿形成，而pH值为6.6时则会抑制半囊肿形成。这些影响都是可逆的。在扫描电子显微镜下，我们发现相邻细胞之间有发育良好的细胞膜结构。在含有足够血清以形成半囊肿的培养基中，细胞间的连接很突出。血清浓度低时，不形成半囊肿，细胞间连接也不那么明显。我们将半囊肿的形成解释为上皮细胞液体运输的一种表现，这种功能需要细胞内一系列分化特征及其整合关联水平。
