Inhibition of Cdc25A Suppresses Hepato-renal Cystogenesis in Rodent Models of Polycystic Kidney and Liver Disease

Abstract

Background & Aims In polycystic kidney (PKD) and liver (PLD) diseases, the normally non-proliferative hepato-renal epithelia acquire a proliferative, cystic phenotype, which is linked to overexpression of Cdc25A and cell cycle deregulation. We investigated the effects of Cdc25A inhibition in mice and rats, via genetic and pharmacological approaches. Methods Cdc25A+/− mice (which have reduced levels of Cdc25A) were cross-bred with Pkhd1del2/del2 mice (which have increased levels of Cdc25A and develop hepatic cysts). Cdc25A expression was analyzed in livers of control and PCK rats, control and Pkd2ws25/− mice, healthy individuals, and patients with PLD. We examined effects of pharmacologic inhibition of Cdc25A with Vitamin K3 (VK3) on the cell cycle, proliferation, and cyst expansion in vitro; hepato-renal cystogenesis in PCK rats and Pkd2ws25/− mice; and expression of Cdc25A and the cell cycle proteins regulated by Cdc25A. We also examined effects of the Cdc25A inhibitor PM-20 on hepato-renal cystogenesis in Pkd2ws25/− mice. Results Liver weights and hepatic and fibrotic areas were decreased by 32%–52% in Cdc25A+/−:Pkhd1del2/del2 mice, compared to Pkhd1del2/del2 mice.VK3 altered the cell cycle and reduced proliferation of cultured cholangiocytes by 32%–83% and decreased growth of cultured cysts by 23%–67%. In PCK rats and Pkd2ws25/− mice, VK3 reduced liver and kidney weights and hepato-renal cystic and fibrotic areas by 18%–34%. PM-20 decreased hepato-renal cystogenesis in Pkd2ws25/− mice by 15%. Conclusions Cdc25A inhibitors block cell cycle progression and proliferation, reduce liver and kidney weights and cyst growth in animal models of PKD and PLD, and might be developed as therapeutics for these diseases.

Therapeutic Targets in Polycystic Liver Disease

“…Levels of cAMP are elevated in cystic cholangiocytes [21] influencing cellular pathways known to be defective in PLD. Several examples include: (i) cell proliferation involves cAMP down-stream effectors, such as EPAC1, EPAC2, PKA and ERK1/2 [21, 22]; (ii) expression of the cell cycle proteins is cAMP-regulated [23]; (iii) fluid secretion into cystic lumen is enhanced in response to cAMP elevation and requires the water channel AQP1 and the ion transporters, CFTR and AE2 [24]; and (iv) cilia in cystic cells lack the components of the cAMP signaling pathway (e.g., adenylyl cyclase 5/6, A kinase anchoring protein 150 (AKAP150), PKA and phosphodiesterase 4C) subsequently interrupting cross-talk between cAMP and intracellular calcium; as a result cholangiocyte proliferation and cyst growth are increased. Importantly, a number of studies suggest that targeting the components of the cAMP machinery in cystic cholangiocytes attenuates hepatic cystogenesis.…”

“…The cell cycle profiles of cystic cholangiocytes are different from control cells likely resulting from the over-expression of the master cell cycle regulator, Cdc25A [23]. Cdc25A overexpression is associated with an increased proportion of cholangiocytes that have atypical centrosomal positioning, supernumerary centrosomes, multipolar spindles and extra cilia [43].…”

“…As a result, repressed cell proliferation and cyst growth in vitro was achieved. Genetic elimination of Cdc25A from cystic cholangiocytes by cross-breeding of Cdc25A +/- mice with Pkhd1 del2/del2 mice (an animal model of ARPKD) reduced hepatic cystogenesis in Cdc25A +/- ;Pkhd1 del2/del2 double mutants [23]. Therefore these data provided the rationale for testing the effects of Cdc25A inhibition on disease progression in the pre-clinical trial using PCK rats and Pkd2 WS25/- mice.…”

Bile Acids in Polycystic Liver Diseases: Triggers of Disease Progression and Potential Solution for Treatment

“…Since the last decade, intense efforts are being focused on understanding the molecular mechanisms involved in the pathogenesis of these diseases in order to find new pharmacological targets for medical treatment [2] . In this regard, hepatic cystogenesis involves DPM [10] , increased cholangiocyte proliferation [11,12] and secretion [13] , ciliary and centrosomal abnormalities [14] , altered cell-matrix interaction [15] , neoangiogenesis [16] , global microR-NA dysregulation [17] , and all of these features are associated with increased cyclic adenosine monophosphate (cAMP) levels [18] and decreased calcium (Ca 2+ ) concentration [11,19] in cystic cholangiocytes. Of note, the role of bile acids in the pathophysiology of PLDs is currently attracting significant attention.…”

The Zebrafish as a Model to Study Polycystic Liver Disease

“…We previously showed that both pasireotide and VK3 affected hepatic and renal cystogenesis in PCK rats and Pkd2 WS25/ -mice. 3,5,8 We also studied the chemical chaperone, sodium 4-PBA, which suppresses endoplasmic reticulum (ER) stress by chemically enhancing the ER capacity to cope with the expression of misfolded proteins. Both proteins implicated in cystic liver disease (sec63 and prkcsh) reside in the ER and are involved in the processing of glycoproteins to prevent protein misfolding or retention of proteins in the ER.…”