Functional inhibition of BCL2 is needed to increase the susceptibility to apoptosis to SMO inhibitors in diffuse large B-cell lymphoma of germinal center subtype.
Previously, we have demonstrated that inhibition of Hedgehog pathway induces predominantly apoptosis in diffuse large B-cell lymphoma (DLBCL) cell lines of activated B-cell (ABC) type but predominantly cell cycle arrest in those of germinal center (GC). Here, we explored the possibility of overcoming the resistance to apoptosis to SMO inhibitors in five DLBCL cells of GC type using the combination of the SMO inhibitor HhAntag (Genentech Inc) with the BH3 mimetic ABT-737 (Abbott Laboratories). As controls we have used two DLBCL of ABC type (OCI-LY10 and OCI-LY3). Combinatorial treatments were performed with increasing concentrations of the HhAntag with low doses (equal or less than the IC20) of ABT-737. MTS assays were used to detect changes in cell viability and Annexin-V and PARP1 cleavage assays were used to detect apoptosis. Combining low doses of ABT-737 with increasing concentrations of HhAntag in GC DLBCL cell lines resulted in significantly increase of apoptosis in comparison to treatments with the SMO inhibitor alone. We concluded that in GC DLBCL cell lines, in contrast to those of ABC type, functional inhibition of BCL2 family members is usually needed to overcome the resistance to apoptosis to SMO inhibitors. These findings provide a rationale to explore the use of SMO and BCL2 inhibitors as adjuvant therapy for treatment of DLBCL of GC type.
Department of Hematopathology, The University of Texas MD Anderson Cancer Center, Unit 72, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
Kranthi
K
Kunkalla
Yadong
Y
Liu
Changju
C
Qu
Vasiliki
V
Leventaki
Nitin K
NK
Agarwal
Rajesh R
RR
Singh
Francisco
F
Vega
D000813:Anilides / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins / Q000096:biosynthesis / Q000235:genetics; D001713:Biphenyl Compounds / Q000494:pharmacology*; D045744:Cell Line, Tumor / Q000187:drug effects / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D019008:Drug Resistance, Neoplasm / Q000187:drug effects; D004354:Drug Screening Assays, Antitumor; D004357:Drug Synergism; D018858:Germinal Center / Q000473:pathology; D006801:Humans; D020128:Inhibitory Concentration 50; D016403:Lymphoma, Large B-Cell, Diffuse / Q000473:pathology*; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics; D009596:Nitrophenols / Q000494:pharmacology*; D010879:Piperazines / Q000494:pharmacology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000037:antagonists & inhibitors*; D011725:Pyridines / Q000494:pharmacology*; D043562:Receptors, G-Protein-Coupled / Q000037:antagonists & inhibitors*; D015398:Signal Transduction / Q000187:drug effects; D000072086:Smoothened Receptor; D013449:Sulfonamides / Q000494:pharmacology*
C501332:ABT-737; D000813:Anilides; D051017:Apoptosis Regulatory Proteins; D001713:Biphenyl Compounds; C538724:HhAntag691; D009363:Neoplasm Proteins; D009596:Nitrophenols; D010879:Piperazines; D019253:Proto-Oncogene Proteins c-bcl-2; D011725:Pyridines; D043562:Receptors, G-Protein-Coupled; C491023:SMO protein, human; D000072086:Smoothened Receptor; D013449:Sulfonamides