Expression and secretion of VEGF isoforms in MM.1S, patient MM, and patient PCL cells.

(A) MM.1S, patient MM, and patient PCL cells express VEGF. Equal amounts of RNA were reverse transcribed to generate cDNA, which was subjected to VEGF-specific PCR amplification by means of paired primers as described in “Materials and methods.” Three splice variants coding for the secreted isoforms VEGF₁₂₁ (516 bp), VEGF₁₄₅ (588 bp), and VEGF₁₆₅ (648 bp) were amplified from all cells. The quality of RNA was confirmed by RT-PCR amplification of β-actin. MWM indicates molecular weight marker. (B) MM.1S, patient MM cells, and patient PCL cells secrete VEGF. Supernatants from equal numbers of cells (1 × 10⁶) were collected after 48 hours and analyzed for VEGF protein by ELISA.