A 366

The HMT inhibitors used were Bix01294 (Sigma‐Aldrich, #B9311), UNC0638 (Sigma‐Aldrich, #U4885), and A‐366 (Sigma‐Aldrich, #SML4110). The HMT inhibitors were dissolved in DMSO and tested in the 1–10 micromolar range to identify concentrations that reduce Histone H3K9me3 levels with minimal toxicity (Bix01294, 2 µM, 24 hr; UNC0638, 3 µM, 24 hr; A‐366, 3 µM, 72 hr). The Zmpste24 protease inhibitor lopinavir (LPV; Cayman Chemicals, #13854) was dissolved in DMSO and used as described (20 µM, 72 hr) to inhibit proteolytic processing of prelamin A. Human fibroblasts were exposed to ionizing radiation (5 Gy), returned to the incubator for 30 min, and subsequently analyzed by IF microscopy. The siRNA to the Ran import factor NTF2 (Santa Cruz, #sc‐36105) and a control siRNA (Fisher, #AM4635) were introduced into normal human fibroblasts (80% confluence) at a concentration of 10 µM using Lipofectamine RNAiMAX (Invitrogen). The cells were analyzed ~96 hr post‐transfection.

Human gastric cancer cell lines [AGS (CRL-1739), SGC-7901, MKN-28, and MKN-45], prostate cancer cell line PC-3 (CRL-1435), colon cancer cell line LoVo (CCL-229), normal gastric epithelial GES-1 cells, and human endothelial cell line HUVEC (CRL-1730) were purchased from the American Type Culture Collection (Rockville, MD) and Type Culture Collection of Chinese Academy of Sciences (Shanghai, China). Cell lines were authenticated by the provider, and used within 6 months after resuscitation of frozen aliquots. Cancer cell lines were grown in RPMI1640 medium (Life Technologies, Inc., Gaithersburg, MD) containing 10% fetal bovine serum (Life Technologies, Inc.), penicillin (100 U/ml), and streptomycin (100 μg/ml). The HUVEC cell line was cultured in Ham’s F12K medium supplemented with 2 mmol/L L-glutamine, 0.1 mg/ml heparin, 0.03 mg/ml endothelial cell growth supplement (Millipore, Billerica, MA), and 10% fetal bovine serum (Life Technologies, Inc.), and used during passages 10 to 25. Cells were maintained at 37 °C in a humidified atmosphere of 5% CO₂, and applied for transfection or treatment with C646, GSK343, or A-366 (Sigma, St. Louis, MO) as indicated.