Inhibition of the aquaporin 3 water channel increases the sensitivity of prostate cancer cells to cryotherapy

Aquaporins (AQPs) are intrinsic membrane proteins that facilitate selective water and small solute movement across the plasma membrane. In this study, we investigate the role of inhibiting AQPs in sensitising prostate cancer cells to cryotherapy. PC-3 and DU145 prostate cancer cells were cooled to 0, −5 and −10°C. The expression of AQP3 in response to freezing was determined using real-time quantitative polymerase chain reaction (RT–qPCR) and western blot analysis. Aquaporins were inhibited using mercuric chloride (HgCl2) and small interfering RNA (siRNA) duplex, and cell survival was assessed using a colorimetric assay. There was a significant increase in AQP3 expression in response to freezing. Cells treated with AQP3 siRNA were more sensitive to cryoinjury compared with control cells (P<0.001). Inhibition of the AQPs by HgCl2 also increased the sensitivity of both cell lines to cryoinjury and there was a complete loss of cell viability at −10°C (P<0.01). In conclusion, we have shown that AQP3 is involved directly in cryoinjury. Inhibition of AQP3 increases the sensitivity of prostate cancer cells to freezing. This strategy may be exploited in the clinic to improve the efficacy of prostate cryotherapy

Relative expression of mRNAs related to cavitation process in bovine embryos produced in vivo and in vitro

The objectives of this work were to identify and to evaluate possible differences on gene expression of aquaporins and Na/K-ATPases transcripts between embryos in vivo and in vitro produced. For each group, 15 blastocysts distributed in three pools were used for RNA extraction followed by amplification and reverse transcription. The resulting cDNAs were submitted to Real-Time PCR, using the GAPDH gene as endogenous control. It was not possible to identify AQP1 transcripts. Relative expression of AQP3 (1.33 ± 0.78) and AQP11 (2.00 ± 1.42) were not different in blastocysts in vitro and in vivo produced. Na/K-ATPase &#945;1 gene (2.25 ± 1.07) was overregulated whereas Na/K-ATPase &#946;2 transcripts 0.40 ± 0.30) did not differ among blastocysts produced in vitro from those produced in vivo. Transcripts for gene AQP1 are not present in bovine blastocysts. In vitro culture system does not alter expression of genes AQP3, AQP11 and Na/K-ATPase &#946;2 genes, however, it affects expression of Na/K-ATPase &#945;1.Os objetivos neste trabalho foram identificar e avaliar possíveis diferenças na expressão gênica de transcritos de Aquaporina e ATPases-Na/K presentes em embriões produzidos in vivo e in vitro. Para cada grupo, 15 blastocistos distribuídos em três conjuntos foram utilizados para a extração do RNA, seguida da amplificação e da transcrição reversa. Os DNAs complementares foram submetidos à reação em cadeia da enzima polimerase em tempo real, utilizando-se o gene GAPDH como controle endógeno. Não foi possível identificar transcritos de AQP1. A expressão relativa dos genes AQP3 (1,33 ± 0,78) e AQP11 (2,00 ± 1,42) não foi diferente em blastocistos produzidos in vitro e in vivo. O gene ATPase-Na/K &#945;1 (2,25 ± 1,07) encontrou-se sobrerregulado, enquanto o gene ATPase-Na/K &#946;2 (0,40 ± 0,30) não diferiu entre os blastocistos produzidos in vitro e aqueles produzidos in vivo. Transcritos para o gene AQP1 não estão presentes em blastocistos bovinos. O sistema de cultivo in vitro não influencia a expressão dos genes AQP3, AQP11 e ATPase-Na/K &#946;2, porém altera a expressão do gene ATPase-Na/K &#945;1

Comparative functional analysis of aquaporins/glyceroporins in mammals and anurans

Maintenance of fluid homeostasis is critical to establishing and maintaining normal physiology. The landmark discovery of membrane water channels (aquaporins; AQPs) ushered in a new area in osmoregulatory biology that has drawn from and contributed to diverse branches of biology, from molecular biology and genomics to systems biology and evolution, and from microbial and plant biology to animal and translational physiology. As a result, the study of AQPs provides a unique and integrated backdrop for exploring the relationships between genes and genome systems, the regulation of gene expression, and the physiologic consequences of genetic variation. The wide species distribution of AQP family members and the evolutionary conservation of the family indicate that the control of membrane water flux is a critical biological process. AQP function and regulation is proving to be central to many of the pathways involved in individual physiologic systems in both mammals and anurans. In mammals, AQPs are essential to normal secretory and absorptive functions of the eye, lung, salivary gland, sweat glands, gastrointestinal tract, and kidney. In urinary, respiratory, and gastrointestinal systems, AQPs are required for proper urine concentration, fluid reabsorption, and glandular secretions. In anurans, AQPs are important in mediating physiologic responses to changes in the external environment, including those that occur during metamorphosis and adaptation from an aquatic to terrestrial environment and thermal acclimation in anticipation of freezing. Therefore, an understanding of AQP function and regulation is an important aspect of an integrated approach to basic biological research