*2.1. Reagents and Antibodies*

Antibodies against CAV1 (N-20: sc-894) and XIAP1 (H-202: sc-11426) were from Santa Cruz (Santa Cruz, CA, USA), against CCND1 (92G2: #2978) and GFP (D5.1: #2956) from Cell Signalling Technology (Denvers, MA, Germany), against PCNA (PC10: GTX20029) from GeneTex (Irvine, CA, USA), against TRIAP1 from ProteinTech Group [15351-1-AP, (WB) Rosemont, IL, USA] and LSBio [LS-C346398-100, (Histology) Seattle, WA, USA), against SURVIVIN (NB500-201) from Novus Biologicals (Centennial, CO, USA) and against β-actin (clone AC-74, A2228) from Sigma-Aldrich (St. Louis, MO, USA). The rabbit anti human ASA antibody BE#3 was previously described [18] and the goa<sup>t</sup> anti ASM antibody was kindly provided by Prof. K. Sandhoff (Bonn, Germany) [19].

### *2.2. Cell Culture Conditions*

The human prostate cancer cell lines PC3, DU145 and LNCaP, the human skin fibroblast cell line HS5 and the human prostate fibroblast cell line WPMY-1 were from ATCC (Manassas, VA, USA) and cultured in RPMI Medium (Gibco, ThermoFisher, Waltham, MA, USA) supplemented with 10% foetal bovine serum and 100 U/mL Penicillin/Streptomycin under standard cell culture conditions (37 ◦C, 5% CO2, 95% humidity) and passaged every 3–4 days. CAV1 mRNA levels were down-regulated in indicated cells using shRNA technology as previously described [11,20,21]. For transient transfection of cells, human TRIAP1 cDNA with a C-terminal GFP-tag cloned into pCMV6-AC-GFP was used [15]. For selection of transfected cells, 500 μg/mL G418/Neomycin (Merck/Millipore, Darmstadt, Germany) was used.

### *2.3. Irradiation of Cell Cultures*

Radiation was performed using the Isovolt-320-X-ray machine (Seifert-Pantak) at 320 kV, 10 mA with a 1.65 mm aluminium filter and a distance of about 500 mm to the object being irradiated [21]. The X-ray tube operated at 90 kV (~45 keV X-rays) and the dose rate was about 3 Gy/min [22].
