Effects of lonidamine on testicular and epididymal proteins in the rat

The lonidamine derivative H2-gamendazole reduces cyst formation in polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is a debilitating renal neoplastic disorder with limited treatment options. It is characterized by the formation of large fluid-filled cysts that develop from kidney tubules through abnormal cell proliferation and cyst-filling fluid secretion driven by cAMP-dependent Cl- secretion. We tested the effectiveness of the indazole carboxylic acid H2-gamendazole (H2-GMZ), a derivative of lonidamine, to inhibit these processes using in vitro and in vivo models of ADPKD. H2-GMZ was effective in rapidly blocking forskolin-induced, Cl--mediated short-circuit currents in human ADPKD cells, and it significantly inhibited both cAMP- and epidermal growth factor-induced proliferation of ADPKD cells. Western blot analysis of H2-GMZ-treated ADPKD cells showed decreased phosphorylated ERK and decreased hyperphosphorylated retinoblastoma levels. H2-GMZ treatment also decreased ErbB2, Akt, and cyclin-dependent kinase 4, consistent with inhibition of heat shock protein 90, and it decreased levels of the cystic fibrosis transmembrane conductance regulator Cl- channel protein. H2-GMZ-treated ADPKD cultures contained a higher proportion of smaller cells with fewer and smaller lamellipodia and decreased cytoplasmic actin staining, and they were unable to accomplish wound closure even at low H2-GMZ concentrations, consistent with an alteration in the actin cytoskeleton and decreased cell motility. Experiments using mouse metanephric organ cultures showed that H2-GMZ inhibited cAMP-stimulated cyst growth and enlargement. In vivo, H2-GMZ was effective in slowing postnatal cyst formation and kidney enlargement in the Pkd1flox/flox: Pkhd1-Cre mouse model. Thus, H2-GMZ treatment decreases Cl- secretion, cell proliferation, cell motility, and cyst growth. These properties, along with its reported low toxicity, suggest that H2-GMZ might be an attractive candidate for treatment of ADPKD.NEW & NOTEWORTHY Autosomal dominant polycystic kidney disease (ADPKD) is a renal neoplastic disorder characterized by the formation of large fluid-filled cysts that develop from kidney tubules through abnormal cell proliferation and cyst-filling fluid secretion driven by cAMP-dependent Cl- secretion. This study shows that the lonidamine derivative H2-GMZ inhibits Cl- secretion, cell proliferation, and cyst growth, suggesting that it might have therapeutic value for the treatment of ADPKD.

Lonidamine transiently affects spermatogenesis in pubertal CD1 mice

Lonidamine (LND) [1-(2,4-dichlorobenzyl)-1H-indazole-3-carboxylic acid], a well-known antispermatogenic drug, was studied for the first time in pubertal mice to assess its possible effects on spermatogenesis. Male CD1 mice were orally treated on Postnatal Day (PND) 28 with a single dose of LND (100 mg/kg body weight) and sacrificed on PND30, PND42, PND74 and PND123. On PND30 (48 h after dosing), severe testicular effects were evidenced in the treated animals: (a) reduction of the testicular sperm head concentration (approximately 50% of the control value); (b) changes in the spermatogenic cell type distribution (mild decrease of the elongated spermatids and S-phase cells fractions); and (c) morphological alterations of the Sertoli cell cytoplasm and germ cell exfoliation. These changes were recovered in adulthood, on PND74 and PND123. However, no effect on sperm chromatin structure was detected on the epididymal sperm of mature mice by sperm chromatin structure assay, suggesting that LND did not interfere with the process of chromatin reorganization and DNA packaging.

Long-term effects of lonidamine on mouse testes

Lonidamine (LND) [1-(2,4-dichlorobenzyl)-1H-indazole-3-carboxylic acid] is a well-known antispermatogenic drug. The aim of this study was to identify its possible long-term sequelae on the reproductive system of mice as compared with rats, where most data have been obtained until now. Sexually mature CD1 male mice were administered a single dose of LND (200 mg/kg bw by gavage) and killed 24 and 48 h, 6 days and 2, 4 and 8 weeks after the treatment. Testes were collected, weighed and (1) fixed in Bouin's solution for histological analysis or (2) reduced to monocellular suspensions and ethanol fixed to undergo flow cytometry (FCM) DNA content analysis. No effect on body weight and/or food consumption was observed in the treated group in comparison with the control group. Testicular weight was significantly reduced 24 h after the treatment. Reduced seminiferous epithelium with a progressive lack of intercellular cohesion and marked depletion of spermatids, infiltration of granulocytes, desquamation into the tubular lumen and increased intertubular spaces were present by 24 h after the treatment and persisted to a marked degree at 48 h, 6 days and 2 and 4 weeks up to a marked degeneration of tubular structures with absence of spermatogenesis. The same effects, albeit with a moderate severity, were still present 8 weeks after the treatment. As also detected by FCM, primary spermatocytes appeared to be the main cellular target. Sertoli and Leydig cells were remarkably spared. The histological findings are consistent with those previously observed in rats and point out that testicular damage may persist for several weeks after a single-dose administration. Findings are discussed in comparison with testicular toxicity elicited by other xenobiotics.

Recent studies on lonidamine, the lead compound of the antispermatogenic indazol-carboxylic acids

Lonidamine (LND) or [1-(2,4-dichlorobenzyl)-1H-indazole-3-carboxylic acid] is an anticancer and an antispermatogenic drug whose mechanism of action is still incompletely understood. LND is effective against a number of tumors, including head, neck and breast cancers, probably because of the inhibition of mitochondrial electron transport and the enzyme hexokinase and to the induction of apoptosis. Instead, the antispermatogenic activity of LND appeared to be related not only to its energolytic activity but also to other effects activities such as the inhibition of specific chloride channels in the epididymis and the disruption of the inter-Sertoli-germ cell junctions, leading to premature release of germ cells. In addition, we recently reported that, in the rat, LND at the dose of 100 mg/Kg b.w. p.o., a fully active but well tolerated dose, caused specific changes of the testicular and epididymal macroglobulins (alpha(2)-macroglobulin, alpha(1) inhibitor-3 and alpha(1)-macroglobulin). Further studies are needed to elucidate the mechanism of action of LND, the lead compound of an interesting class of antispermatogenic drugs based on the core structure of 1-(2,4-dichlorobenzyl)-indazole-3-carboxylic acid.