Bystander effects induced by the interaction between urothelial cancer cells and irradiated adipose tissue-derived stromal cells in urothelial carcinoma.

Cell-cell interactions between cancer cells and neighboring adipose tissue-derived stromal cells (ATSCs) are known to regulate the aggressiveness of cancer cells. In addition, the radiation-induced bystander effect is an important modulator of cancer cell kinetics. Radiation therapy is often given for urinary cancer, but the biological effects of the irradiated cancer stroma, including adipose tissue, on urothelial carcinoma (UC) remain unclear. We investigated the bystander effect of irradiated ATSCs on UC using a collagen gel culture method to replicate irradiated ATSC-cancer cell interactions after a single 12-Gy dose of irradiation. Proliferative activity, invasive capacity, protein expression and nuclear translocation of p53 binding protein-1 (53BP1) were analyzed. Irradiated ATSCs significantly inhibited the growth and promoted the apoptosis of UC cells in comparison to non-irradiated controls. The invasiveness of UC cells was increased by irradiated ATSCs, but not irradiated fibroblasts. Nuclear translocation of 53BP1 protein due to the bystander effect was confirmed in the irradiated group. Irradiated ATSCs regulated the expressions of the insulin receptor, insulin-like growth factor-1 and extracellular signal-regulated kinase-1/2 in UC. In conclusion, the bystander effect of irradiated ATSCs is a critical regulator of UC, and the actions differed depending on the type of mesenchymal cell involved. Our alternative culture model is a promising tool for further investigations into radiation therapy for many types of cancer.

Cellular and physical microenvironments regulate the aggressiveness and sunitinib chemosensitivity of clear cell renal cell carcinoma.

Renal cell carcinoma (RCC) is the most predominant type of kidney cancer in adults and is responsible for approximately 85% of clinical cases. The tumor-specific microenvironment includes both cellular and physical factors, and it regulates the homeostasis and function of cancer cells. Perirenal adipose tissue and tumor-associated macrophages are the major cellular components of the RCC microenvironment. The RCC microvasculature network generates interstitial fluid flow, which is the movement of fluid through the extracellular compartments of tissues. This fluid flow is a specific physical characteristic of the microenvironment of RCC. We hypothesized that there may be an interaction between the cellular and physical microenvironments and that these two factors may play an important role in regulating the behavior of RCC. To elucidate the effects of adipose tissue, macrophages, and fluid flow stimulation on RCC and to investigate the relationships between these factors, we used a collagen gel culture method to generate cancer-stroma interactions and a gyratory shaker to create fluid flow stimulation. Adipose-related cells, monocytes, and fluid flow influenced the proliferative potential and invasive capacity of RCC cells. Extracellular signal-regulated kinase and p38 signaling were regulated either synergistically or independently by both fluid flow and cellular interactions between RCC and adipose tissue fragments or macrophages. Fluid flow stimulation synergistically enhanced the anti-proliferative effect of sunitinib on RCC cells, but macrophages abolished the synergistic anti-proliferative effect related to fluid flow stimulation. In conclusion, we established a reconstructed model to investigate the cellular and physical microenvironments of RCC in vitro. Our alternative culture model may provide a promising tool for further therapeutic investigations into many types of cancer. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.