Camel urine limits proliferation and modifies cell morphology in human renal tumoral and non-tumoral cells

The widespread ethnomedical practice of dromedary urinotherapy as a remedy against various illnesses is well recognized in traditional dromedary countries, and multiple researchers tried to unravel its bioactive potential and provide scientific evidence through in vivo and in vitro experiments. None of these studies (i) measured urine osmolarity prior to bioactivity testing, which could deeply influence the results of in vitro tests, nor (ii) addressed issues related to cells morphological changes after exposure to camel urines. Taken together, the above aspects point to the need for a "good practice" to be shared by researchers in this field, in order to reduce the variability of in vitro testing of camel urine bioactivity. In this work, using a set of biological samples from animals differing in sex, age, and physiological status, we investigated, the antiproliferative activity of camel urine towards human non-tumoral (HK2) and tumoral renal cells (Caki-1), through cell viability and microscopy analysis, and taking the possible influence of osmolarity into account. We employed cell lines commonly used in toxicological research which, to the best of our knowledge, have not been previously exposed to camel urine. HK2 and Caki-1 cells tolerated well mannitol-induced hyperosmolarity up to 500 mOsm/L. Significant antiproliferative effects were observed only in Caki-1 cells, when exposed to urine solutions (diluted to <500 mOsm/L) from two males out of the ten tested samples, while effects on cell morphology (elongation) were observed only in HK2 cells, when exposed to urine solutions from six samples. The significant antiproliferative effect observed only in tumoral cells looks promising for forthcoming developments in the cancer treatment field. Finally, the presented approach may serve as a guide for future research in this specific, multidisciplinary field.