Journal: Hematological Oncology

Article Title: Targetable Vulnerabilities in MYC‐Driven B Cell Lymphomas Resistant to BCR Extinction

doi: 10.1002/hon.70175

Figure Lengend Snippet: BCR loss reduces Cyclin D3 levels and heightens lymphoma sensitivity to CDK4/6 inhibition. (A) Representative flow‐cytometric analyses of λ ‐MYC lymphoma cells (# 2646) assessing the frequency of BCR + and BCR − subsets co‐cultured at a 50:50 starting ratio and treated for 48 h with increasing doses of Palbociclib. Vehicle (DMSO)–treated cultures served as controls. The starting distribution of BCR + and BCR − cells (day 0) is shown on the left. (B) Quantification of BCR − cell frequency in co‐cultures described in (A) at baseline (day 0) and after 48 h of treatment with Palbociclib (125 nM). Black and grey circles indicate values obtained from lymphomas # 2646 and # 2567, respectively. (C) Cell‐cycle analysis of BCR + and BCR − cells from mixed cultures of λ ‐MYC lymphoma # 2646 following 48 h of treatment with the indicated doses of Palbociclib. Vehicle (DMSO)‐treated cells were used as reference. (D) Immunoblot analysis of Cyclin D3 (CCND3) protein levels in paired BCR + and BCR − lymphoma cells derived from two independent tumors (# 2646 and # 2567). The corresponding densitometric quantification of CCND3 normalized to protein input is reported in the histogram. Data are representative of n = 3 (A), n = 5 (B), n = 3 (C), and n = 3 (D) independent experiments. Statistical comparisons in panel B were performed using a two‐way ANOVA (** p < 0.01; **** p < 0.0001).

Article Snippet: BCR + and BCR − tumor B cells from lymphomas # 2646 and # 2567 were mixed in equal numbers, plated at 1 × 10 5 cells/mL and cultured in medium supplemented respectively with Rapamycin (5, 10 or 20 nM; LC laboratories), Sapanisertib (10, 15 or 30 nM; Selleck Chemicals), CHIR99021 (1 μM; Medchem) or Palbociclib (62.5, 125, or 250 nM; Medchem) for up to 72 h. Vehicle‐treated cells were used as control.

Techniques: Inhibition, Cell Culture, Cell Cycle Assay, Western Blot, Derivative Assay

Journal: Hematological Oncology

Article Title: Targetable Vulnerabilities in MYC‐Driven B Cell Lymphomas Resistant to BCR Extinction

doi: 10.1002/hon.70175

Figure Lengend Snippet: BCR‐null human HGBCL with MYC and BCL2 rearrangements are highly sensitive to CDK4/6 and mTOR inhibition. (A) Flow‐cytometric analysis of surface IG‐Kappa (IGK) and IG‐Lambda (IGL) expression in human BCR‐null HGBCL‐ DH ‐ BCL2 cell lines (WILL‐2, COH‐DHL1, and DoGKIT). IGK + (SU‐DHL‐4) and IGL + (DOGUM) B lymphoma cell lines were included as reference controls. (B) Dose–response curves and IC 50 values for clinically approved CDK4/6 inhibitors (Palbociclib, Ribociclib, Abemaciclib) and mTOR inhibitors (Rapamycin, Everolimus, Sapanisertib) following 72 h treatment of the indicated human BCR‐null HGBCL‐DH‐ BCL2 cell lines.

Article Snippet: BCR + and BCR − tumor B cells from lymphomas # 2646 and # 2567 were mixed in equal numbers, plated at 1 × 10 5 cells/mL and cultured in medium supplemented respectively with Rapamycin (5, 10 or 20 nM; LC laboratories), Sapanisertib (10, 15 or 30 nM; Selleck Chemicals), CHIR99021 (1 μM; Medchem) or Palbociclib (62.5, 125, or 250 nM; Medchem) for up to 72 h. Vehicle‐treated cells were used as control.

Techniques: Inhibition, Expressing