Fig. 1

N-Myc confers LNCaP cells ADT resistance and C4–2 cells Enzalutamide resistance. a Immunoblots to show the decreased AR and PSA expression but increased expression of neuroendocrine markers, CgA and NSE, in both N-Myc overexpressing LNCaP and C4–2 cells. GAPDH was used as a loading control. b Growth curve for LNCaP/Vec vs. LNCaP/N-Myc and C4–2/Vec vs. C4–2/N-Myc cells cultured in regular medium and cell number was counted at the indicated time points. All the numbers were normalized to day 0. c Overexpression of N-Myc increased colony formation in both LNCaP and C4–2 cell lines but had a more profound effect on LNCaP cells. Upper panels showed representative images and lower panels were quantifications. d Growth curve for LNCaP/Vec and LNCaP/N-Myc cells cultured in charcoal-stripped medium (ADT) and cell numbers was counted at the indicated time points. All the numbers were normalized to day 0. e LNCaP/Vec and LNCaP/N-Myc cells were injected into the flanks of nude mice. Tumor volume was measured twice a week at indicated time points (n = 4 for each group). f Castration was initiated when tumor volume reached ~ 200mm³ and set as day 0. Tumor volume was measured twice a week and relative volume was reported (n = 4 for each group). g Dose response of Enzalutamide at 72 h using MTS cell viability assay for C4–2/Vec and C4–2/N-Myc cells. *p < 0.05, **p < 0.005