biostudies-literatureOkamoto RNCI NIH HHS2464-73https://www.ebi.ac.uk/biostudies/studies/S-EPMC3288172biostudies-literatureUnknown130(10)19-nor-14-epi-23-yne-1,25(OH)(2) D(3) (inecalcitol) is a unique vitamin D(3) analog. We evaluated the activity of inecalcitol in a human prostate cancer model system. The analog was 11-fold more potent than 1,25(OH)(2) D(3) in causing 50% clonal growth inhibition of androgen-sensitive human prostate cancer LNCaP cells. Inecalcitol, more than 1,25(OH)(2) D(3) , reduced in a dose-dependent manner the expression levels of the transcription factor ETS variant 1 and the serine/threonine protein kinase Pim-1, both of which are upregulated in prostate cancer. Remarkably, dose challenge experiments revealed that inecalcitol maximal tolerated dose (MTD) by intraperitoneal (i.p.) administration was 30 μg/mouse (1,300 μg/kg) three times per week, while we previously found that the MTD of 1,25(OH)(International journal of cancerInecalcitol, an analog of 1α,25(OH)(2) D(3) , induces growth arrest of androgen-dependent prostate cancer cells.PMC3288172U54 CA143930R01 CA026038R01 CA026038-32U54 CA143930-01Shen MDelansorne RWakimoto NSaid JWDoan NBHo QHKoeffler HPOkamoto RAkagi TfalseInecalcitol, an analog of 1α,25(OH)(2) D(3) , induces growth arrest of androgen-dependent prostate cancer cells.19-nor-14-epi-23-yne-1,25(OH)(2) D(3) (inecalcitol) is a unique vitamin D(3) analog. We evaluated the activity of inecalcitol in a human prostate cancer model system. The analog was 11-fold more potent than 1,25(OH)(2) D(3) in causing 50% clonal growth inhibition of androgen-sensitive human prostate cancer LNCaP cells. Inecalcitol, more than 1,25(OH)(2) D(3) , reduced in a dose-dependent manner the expression levels of the transcription factor ETS variant 1 and the serine/threonine protein kinase Pim-1, both of which are upregulated in prostate cancer. Remarkably, dose challenge experiments revealed that inecalcitol maximal tolerated dose (MTD) by intraperitoneal (i.p.) administration was 30 μg/mouse (1,300 μg/kg) three times per week, while we previously found that the MTD of 1,25(OH)(2012-01-01T00:00:00Z2012 May2025-06-27T03:05:06.627Z2025-06-27T03:05:06.627ZS-EPMC32881722173234510.1002/ijc.26279