1. A LAN6 CHLA90 CHLA15 SK-N-RA DMSO 13-cis RA
Supplementary Figure 1: Definition of retinoid resistance by morphology, and TALE family gene expression response to RA. A) Prototypical RA-sensitive and RA-resistant NB cell lines, treated with DMSO and 13-cisRA. The cell lines LAN-6 and CHLA90 are RA-sensitive cell lines, with smaller cell bodies and some neurite formation in complete media under control conditions (DMSO); when treated with 13-cisRA, proliferation slows and long neuritic processes develop extending from the cell bodies. In contrast, the RA-resistant cells CHLA15 and SK-N-AS have flatter and larger cell bodies under control conditions and no neurite formation or significant apoptosis when treated with 13-cisRA. B) Expression of TALE gene family members other than PBX1 do not correlate with treatment with 13-cisRA. The relative mRNA expression of PBX2, PBX3, PBX4 (top row), MEIS1, MEIS2, MEIS3 (middle row), and PKNOX1 and PKNOX2 in 4 RA-resistant cell lines (blue bars) and 11 RA-sensitive cell lines (red bars), as measured by RT-qPCR. A
LAN6
CHLA90
Supplementary Figure 3: PBX1 induces morphological and cytoskeletal changes consistent with differentiation in neuroblastoma. A) Morphology of SHSY5Y cells. Cells were grown in complete media in the presence of DMSO (left column) or 10 µM 13-cis RA for 5 days, then examined under 10X magnification phase microscopy. Neurite extensions are indicated (open arrows).
CHLA15
SK-N-RA
DMSO
13-cis RA

2. Supplementary Figure 1B (see legend above)
PBX2
PBX3
PBX4
MEIS1
MEIS2
MEIS3
Supplementary Figure 1: Expression of TALE family genes in neuroblastoma cells lines treated with vehicle or 13-cis retinoic acid. The relative expression of PBX2, PBX3, PBX4 (top row), MEIS1, MEIS2, MEIS3 (middle row), and PKNOX1 and PKNOX2 in 3 RA-resistant cell lines (blue bars) and 5 RA-sensitive cell lines (red bars).
PKNOX1
PKNOX2