Mechanisms, consequences and regulation of pH non-uniformity in 3-D tissue structures: implications on cancer therapy

我们的目的是研究多细胞组织中调节酸碱平衡(PH)的机制，特别是肿瘤。活细胞产生酸，这是新陈代谢的最终产物。酸必须从细胞中排出，排到最近的毛细血管，以保持细胞内允许的pH值(Phi)，以保持细胞的健康功能。有效地排出酸也是维持多细胞组织均一PHI所必需的。这对于血流不足和代谢活跃的组织来说尤其关键，例如发展中的肿瘤，在这些组织中，可变的细胞到毛细血管的扩散距离容易受到phi梯度和核心酸度的影响。尽管在分离细胞的phi调节领域已经取得了重大进展，但人们对在组织水平上工作的综合机制知之甚少。可能对后者有贡献的分子包括pH缓冲剂、碳酸氢酶、缝隙连接通道和酸/碱膜转运蛋白。我们将使用分子生物学、pH成像和计算模型来研究这些机制。这项研究将使用癌症衍生细胞的大型三维集群(“球体”)作为肿瘤发展的体外模型。癌症良好的生存前景可能表明，在肿瘤中实施了有效的排酸机制。抑制这些机制可能会为癌症的治疗提供新的治疗策略。细胞内外pH值的调节也可能影响细胞对某些目前用于化疗的弱碱性药物的摄取。

Our aim is to study the mechanisms that regulate the acid/base balance (pH) in multi-cellular tissue, with particular emphasis on tumours.Living cells produce acid, an end-product of metabolism. Acid must be vented out of cells, to the nearest blood capillary, in order to maintain an intracellular pH (pHi) that is permissive for healthy cell function. Efficient venting of acid is also necessary to maintain uniform pHi across multi-cellular tissue. This is particularly critical for under-perfused and metabolically-active tissues, such as developing tumours, where variable cell-to-capillary diffusion distances predispose to pHi-gradients and core-acidity.Although significant progress has been made in the field of pHi-regulation in isolated cells, little is known about the integrated mechanisms that operate at tissue-level. Molecules likely to contribute to the latter include pH buffers, carbonic anhydrase enzymes, gap junction channels and acid/base membrane transporters. We will investigate these mechanisms using molecular biology, pH imaging and computational modelling. The research will use large, three-dimensional clusters (‘spheroids’) of cancer-derived cells as an in vitro model of developing tumours.The good survival prospects of cancer may suggest that efficient mechanisms for venting acid are implemented in tumours. Inhibiting these mechanisms may offer novel therapeutic strategies for treating cancer. Manipulation of pH within and outside cells may also affect the cellular uptake of certain weakly basic drugs that are currently used in chemotherapy.