R-CHOP Resistance Research Articles

PI3Kδ activation, IL6 overexpression, and CD37 loss cause resistance to naratuximab emtansine in lymphomas

AbstractCD37-directed antibody and cellular-based approaches have shown preclinical and promising early clinical activity. Naratuximab emtansine (Debio 1562; IMGN529) is an antibody-drug conjugate (ADC) incorporating an anti-CD37 monoclonal antibody conjugated to the maytansinoid DM1 as payload, with activity as a single agent and in combination with rituximab in patients with lymphoma. We studied naratuximab emtansine and its free payload in 54 lymphoma models, correlated its activity with CD37 expression, characterized 2 resistance mechanisms, and identified combination partners providing synergy. The activity, primarily cytotoxic, was more potent in B- than T-cell lymphoma cell lines. After prolonged exposure to the ADC, 1 diffuse large B-cell lymphoma (DLBCL) cell line developed resistance to the ADC due to the CD37 gene biallelic loss. After CD37 loss, we also observed upregulation of interleukin-6 (IL6) and related transcripts. Recombinant IL6 led to resistance. Anti-IL6 antibody tocilizumab improved the ADC’s cytotoxic activity in CD37+ cells. In a second model, resistance was sustained by a PIK3CD activating mutation, with increased sensitivity to PI3Kδ inhibition and a functional dependence switch from MCL1 to BCL2. Adding idelalisib or venetoclax overcame resistance in the resistant derivative and improved cytotoxic activity in the parental cells. In conclusion, targeting B-cell lymphoma with the naratuximab emtansine showed vigorous antitumor activity as a single agent, which was also observed in models bearing genetic lesions associated with inferior outcomes, such as MYC translocations and TP53 inactivation or R-CHOP (rituximab, cyclophosphamide, doxorubicin, Oncovin [vincristine], and prednisone) resistance. Resistant DLBCL models identified active combinations of naratuximab emtansine with drugs targeting IL6, PI3Kδ, and BCL2.

Validation of single nucleotide polymorphisms potentially related to R-CHOP resistance in diffuse large B-cell lymphoma patients.

Aim: Diffuse large B-cell lymphoma (DLBCL) is the most common B-cell non-Hodgkin lymphoma (NHL). Despite the availability of clinical and molecular algorithms applied for the prediction of prognosis, in up to 30%-40% of patients, intrinsic or acquired drug resistance occurs. Constitutional genetics may help to predict R-CHOP resistance. This study aimed to validate previously identified single nucleotide polymorphisms (SNPs) in the literature as potential predictors of R-CHOP resistance in DLBCL patients, SNPs. Methods: Twenty SNPs, involved in R-CHOP pharmacokinetics/pharmacodynamics or other pathobiological processes, were investigated in 185 stage I-IV DLBCL patients included in a multi-institution pharmacogenetic study to validate their previously identified correlations with resistance to R-CHOP. Results: Correlations between rs2010963 (VEGFA gene) and sex (P = 0.046), and rs1625895 (TP53 gene) and stage (P = 0.003) were shown. After multivariate analyses, a concordant effect (i.e., increased risk of disease progression and death) was observed for rs1883112 (NCF4 gene) and rs1800871 (IL10 gene). When patients were grouped according to the revised International Prognostic Index (R-IPI), both these SNPs further discriminated progression-free survival (PFS) and overall survival (OS) of the R-IPI-1-2 subgroup. Overall, patients harboring the rare allele showed shorter PFS and OS compared with wild-type patients. Conclusions: Two out of the 20 study SNPs were validated. Thus, these results support the role of previously identified rs1883112 and rs1800871 in predicting DLBCL resistance to R-CHOP and highlight their ability to further discriminate the prognosis of R-IPI-1-2 patients. These data point to the need to also focus on host genetics for a more comprehensive assessment of DLBCL patient outcomes in future prospective trials.

Sustained activation of non-canonical NF-κB signalling drives glycolytic reprogramming in doxorubicin-resistant DLBCL.

DLBCL is the most common lymphoma with high tumor heterogeneity. Treatment refractoriness and relapse from R-CHOP therapy in patients remain a clinical problem. Activation of the non-canonical NF-κB pathway is associated with R-CHOP resistance. However, downstream targets of non-canonical NF-κB mediating R-CHOP-induced resistance remains uncharacterized. Here, we identify the common mechanisms underlying both intrinsic and acquired resistance that are induced by doxorubicin, the main cytotoxic component of R-CHOP. We performed global transcriptomic analysis of (1) a panel of resistant versus sensitive and (2) isogenic acquired doxorubicin-resistant DLBCL cell lines following short and chronic exposure to doxorubicin respectively. Doxorubicin-induced stress in resistant cells activates a distinct transcriptional signature that is enriched in metabolic reprogramming and oncogenic signalling. Selective and sustained activation of non-canonical NF-κB signalling in these resistant cells exacerbated their survival by augmenting glycolysis. In response to doxorubicin, p52-RelB complexes transcriptionally activated multiple glycolytic regulators with prognostic significance through increased recruitment at their gene promoters. Targeting p52-RelB and their targets in resistant cells increased doxorubicin sensitivity in vitro and in vivo. Collectively, our study uncovered novel molecular drivers of doxorubicin-induced resistance that are regulated by non-canonical NF-κB pathway. We reveal new avenues of therapeutic targeting for R-CHOP-treated refractory/relapsed DLBCL patients.

Beneficial Effect of Microrna-155 in Vincristine Response and Clinical Outcome in Especially GCB Diffuse Large B-Cell Lymphoma

▪R-CHOP is standard treatment for previously untreated diffuse large B-cell lymphoma (DLBCL). Approximately 35-40% of patients relapse following R-CHOP due to drug-specific molecular resistance, and outcome with salvage therapy remain poor. Several clinical trials have tried to improve the R-CHOP regimen by dose adjustments and add on drugs, but with limited clinical benefit, emphasizing that improved understanding of R-CHOP resistance are still relevant and highly needed. Vincristine is essential to the efficacy of R-CHOP, and despite its use for decades, little is known about determinants of resistance in the treatment of DLBCL, which is important when attempting to improve outcome.We hypothesized that miRNAs are involved in the underlying molecular mechanisms by which Vincristine resistance work and that miRNAs hold potential as biomarkers of Vincristine response. By analyses of miRNA microarrays from DLBCL cell lines with different Vincristine sensitivity, we identified lower miR-155 expression in resistant cell lines.The hypothesis was further studied by two different approaches; first, by experimental manipulations of miR-155 expression by lentiviral vectors in DLBCL cell lines, studying the direct impact of miR-155 in Vincristine response, and secondly, by clinical outcome analysis of the prognostic impact of miR-155 expression in two independent DLBCL cohorts.Our results document that miR-155 is directly involved in Vincristine response in DLBCL cells since over-expression of miR-155 increased the Vincristine sensitivity, especially in GCB classified cell lines. Consistently, when miR-155 was downregulated or knocked-out by the CRISPR-Cas9 technology the cells became more resistant.Prognostic impact of miR-155 was evaluated in an in-house cohort of 69 R-CHOP treated patients having miR-155 expression determined by RT-qPCR and in an independent DLBCL meta cohort of 586 patients, who had the miR-155 precursor MIR155HG measured by microarray. Survival analysis was performed overall and according to ABC/GCB subclasses. miR-155 expression did not correlate with clinical outcome after R-CHOP treatment in the entire DLBCL cohort or restricted to ABC classified patients. However, we observed that GCB classified patients with low miR-155 levels had significantly shorter overall and progression-free survival than GCB patients with high miR-155 expression levels (Figure 1). Multivariate Cox regression showed that miR-155 expression added significant and independent prognostic information to the already well-established international prognostic index (IPI) when the analysis was restricted to the GCB subclass.In summary, experimentally we confirmed a direct link between miR-155 and Vincristine response in DLBCL overall and in particular GCB DLBCL. This association is supported by prognostic evaluation in two clinical cohorts treated with R-CHOP, that documents an inferior clinical outcome in GCB classified patients with low miR-155 expression. This suggests that the role of miR-155 in Vincristine response is important enough to affect overall- and progression-free survival especially within the GCB subclass. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

CD24 Contributes to Treatment Effect in ABC-DLBCL Patients with R-CHOP Resistance.

PurposeDiffuse large B-cell lymphoma (DLBCL) is the most common non-Hodgkin’s lymphoma and of which the prognosis of activated B-cell-like (ABC) subtype is poor. Although R-CHOP significantly improves the survival of patients with DLBCL, 20% to 40% of patients were resistant to R-CHOP therapy. Thus, screening for candidate therapeutic targets for R-CHOP resistant patients is urgent. The previous researches have shown that CD24 is related to the development, invasion, and metastasis of cancer. Our project aims to clarify the relationship between CD24 and ABC-DLBCL.Patients and MethodsThe expression of CD24 mRNA in 118 ABC-DLBCL cases treated with R-CHOP was detected by RNAscope, and the relationship between CD24 expression and R-CHOP treatment response was analyzed. The correlation between CD24 expression and treatment efficiency was further analyzed by data downloaded from the Gene Expression Omnibus (GEO) database. The association between CD24 expression and immune response was conducted using Cell-type Identification By Estimating Relative Subsets Of RNA Transcripts (CIBERSORT) methodology and Gene Ontology (GO) biological process (BP) analysis.ResultsThe positive expression rate of CD24 mRNA in ABC-DLBCL patients was 38.1% (45/118). Complete Response (CR) rate was significantly higher in patients with CD24 high expression than those with CD24 low expression (P=0.039; 44.4% vs 26.0%). CR rate was significantly different between CD24 high and low expression groups in the analysis of GEO datasets (P=0.003; 83.2% vs 58.0%). The CD24 high expression patients had significantly lower proportions of T cells and nonspecific immune cells in the CIBERSORT analysis. In addition, T−helper 2 cell differentiation and monocyte chemotaxis were repressed in CD24 high expression group in the GO BP analysis.ConclusionCD24 was correlated with better R-CHOP treatment response and tumor immunosuppression in ABC-DLBCL. CD24 may be a promising signal in treatment and prognosis evaluation in ABC-DLBCL patients.

R-CHOP resistance in diffuse large B-cell lymphoma: biological and molecular mechanisms.

Although the first-line rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone regimen (R-CHOP) substantially improved outcomes for patients with diffuse large B-cell lymphoma (DLBCL), 40% of the patients suffered from relapsed/refractory disease and had poor survival outcomes. The detailed mechanism underlying R-CHOP resistance has not been well defined. For this review, we conducted a thorough search for literature and clinical trials involving DLBCL resistance. We discussed DLBCL biology, epigenetics, and aberrant signaling of the B-cell receptor (BCR), phosphatidylinositol 3-kinase (PI3K)/Akt, nuclear factor kappa light chain enhancer of activated B-cells (NF-κB), and the Janus kinase (JAK)/signal transducer and activator of transcription 3 (STAT3) pathways as defining mechanisms of DLBCL heterogeneity and R-CHOP resistance. The cell of origin, double- or triple-hit lymphoma and double-protein-expression, clonal evolution, tumor microenvironment, and multi-drug resistance help to contextualize DLBCL resistance in an (epi)genetically and biologically comparative manner. With better understanding of the biological and molecular landscape of DLBCL, a more detailed classification system and tailored treatments will ideally become available to further improve the prognosis of DLBCL patients.

Genetic and evolutionary patterns of treatment resistance in relapsed B-cell lymphoma

AbstractDiffuse large B-cell lymphoma (DLBCL) patients are typically treated with immunochemotherapy containing rituximab (rituximab, cyclophosphamide, hydroxydaunorubicin-vincristine (oncovin), and prednisone [R-CHOP]); however, prognosis is extremely poor if R-CHOP fails. To identify genetic mechanisms contributing to primary or acquired R-CHOP resistance, we performed target-panel sequencing of 135 relapsed/refractory DLBCLs (rrDLBCLs), primarily comprising circulating tumor DNA from patients on clinical trials. Comparison with a metacohort of 1670 diagnostic DLBCLs identified 6 genes significantly enriched for mutations upon relapse. TP53 and KMT2D were mutated in the majority of rrDLBCLs, and these mutations remained clonally persistent throughout treatment in paired diagnostic-relapse samples, suggesting a role in primary treatment resistance. Nonsense and missense mutations affecting MS4A1, which encodes CD20, are exceedingly rare in diagnostic samples but show recurrent patterns of clonal expansion following rituximab-based therapy. MS4A1 missense mutations within the transmembrane domains lead to loss of CD20 in vitro, and patient tumors harboring these mutations lacked CD20 protein expression. In a time series from a patient treated with multiple rounds of therapy, tumor heterogeneity and minor MS4A1-harboring subclones contributed to rapid disease recurrence, with MS4A1 mutations as founding events for these subclones. TP53 and KMT2D mutation status, in combination with other prognostic factors, may be used to identify high-risk patients prior to R-CHOP for posttreatment monitoring. Using liquid biopsies, we show the potential to identify tumors with loss of CD20 surface expression stemming from MS4A1 mutations. Implementation of noninvasive assays to detect such features of acquired treatment resistance may allow timely transition to more effective treatment regimens.

PI3K/AKT inhibition reverses R-CHOP resistance by destabilizing SOX2 in diffuse large B cell lymphoma.

Up to one-third of diffuse large B cell lymphoma (DLBCL) patients eventually develop resistance to R-CHOP regimen, while the remaining therapeutic options are limited. Thus, understanding the underlying mechanisms and developing therapeutic approaches are urgently needed.Methods: We generated two germinal center B cell-like (GCB) and activated B cell-like (ABC) subtype R-CHO resistant DLBCL cell lines, of which the tumor-initiating capacity was evaluated by serial-transplantation and stemness-associated features including CD34 and CD133 expression, side population and ALDH1 activity were detected by flow cytometry or immunoblotting. Expression profiles of these resistant cells were characterized by RNA sequencing. The susceptibility of resistant cells to different treatments was evaluated by in vitro CytoTox-glo assay and in tumor-bearing mice. The expression levels of SOX2, phos-AKT, CDK6 and FGFR1/2 were detected in 12 R-CHOP-resistant DLBCL clinical specimens by IHC.Results: The stem-like CSC proportion significantly increased in both resistant DLBCL subtypes. SOX2 expression level remarkably elevated in both resistant cell lines due to its phosphorylation by activated PI3K/AKT signaling, thus preventing ubiquitin-mediated degradation. Further, multiple factors, including BCR, integrins, chemokines and FGFR1/2 signaling, regulated PI3K/AKT activation. CDK6 in GCB subtype and FGFR1/2 in ABC subtype were SOX2 targets, whose inhibition potently re-sensitized resistant cells to R-CHOP treatment. More importantly, addition of PI3K inhibitor to R-CHOP completely suppressed the tumor growth of R-CHO-resistant DLBCL cells, most likely by converting CSCs to chemo-sensitive differentiated cells.Conclusions: The PI3K/AKT/SOX2 axis plays a critical role in R-CHOP resistance development and the pro-differentiation therapy against CSCs proposed in this study warrants further study in clinical trials for the treatment of resistant DLBCL.

Recurrent Patterns of Clonal Evolution in Relapsed-Refractory DLBCL Following Treatment with R-CHOP

Introduction Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin lymphoma and is characterized by its genetic and clinical heterogeneity. Patients can develop DLBCL de novo or as a transformation from other lymphoid malignancies, most commonly follicular lymphoma. For patients with relapsed/refractory DLBCL (rrDLBCL), prognosis is extremely poor with 2-year overall survival of 20-40%. While numerous treatments are under investigation to improve patient outcomes, the success of these treatments has been limited as the genetic mechanisms underpinning treatment resistance are largely unknown. Identifying genomic alterations which contribute to relapse may improve salvage therapy for patients with rrDLBCL or allow patients to be stratified prior to frontline treatment. Methods To identify genomic alterations which contribute to R-CHOP resistance, we previously collected samples from patients enrolled in four clinical trials exploring candidate salvage therapies for patients with rrDLBCL as well as a retrospective rrDLBCL cohort, totalling 193 cases (133 de-novo DLBCL, 60 transformed). Plasma samples were collected from each patient upon relapse along with diagnostic tissue biopsies where available. A combination of exome sequencing and target-panel sequencing of lymphoma associated genes was performed on circulating tumour DNA and tissue biopsies (if available). Mutations implicated in R-CHOP resistance were identified through two complimentary strategies. First, the mutation frequency of recurrently mutated genes across de novo rrDLBCL samples was compared to a cohort of unrelated diagnostic DLBCL cases (n=1691) to identify genes enriched for mutations. Second, the genomic landscape and tumor clonal structure was compared prior to and following R-CHOP to identify mutations in each patient that underwent clonal expansion following therapy. Anti-CD20 antibody binding affinity of MS4A1 mutants was evaluated using flow cytometry on transfected CHO-S cells. Results We have identified five genes enriched for mutations in our rrDLBCL cohort relative to diagnostic DLBCL: KMT2D (Mutated in 49%, Q=0.0385), TP53 (47%, Q=1.07x10-9), FOXO1 (11%, Q=0.0727), NFKBIE (11%, Q=0.0385), and MS4A1 (8%, Q=0.0522). Consistent with its characterization as a poor prognostic marker, mutations in TP53 were typically present at diagnosis and remained stable following R-CHOP therapy for both de novo and transformed DLBCL (23/27 cases, 85%). Recurrent mutations affecting Arg248 of TP53 (6.8%, Q=0.0413) were also clonally stable and have previously been associated with poor overall survival across several cancer types. The histone methyltransferase KMT2D is dominated by nonsense and frameshift mutations which were stable or underwent clonal expansion following R-CHOP (17/19, 89%). Recurrent missense mutations in MS4A1 targeted the small loop and adjacent transmembrane domains of CD20, including several patients with a Tyr86 mutation. Transfected cells carrying Tyr86Cys or Leu66Arg mutations were not bound by rituximab or other anti-CD20 antibodies including obinituzumab and ofatumumab. Subclonal populations containing MS4A1 mutations underwent clonal expansion (6 cases) or were stable (1 case) following treatment, including one case with multiple MS4A1 mutations in distinct subclonal populations which both underwent clonal expansion. In another unique case, a series of ctDNA samples were available prior to and following R-CHOP and salvage therapy, where we again observed convergent evolution of two mutually exclusive clonal subpopulations containing MS4A1 mutations. The first subpopulation underwent clonal expansion following frontline therapy but was extinguished following salvage therapy, while the other subpopulation underwent clonal expansion following salvage therapy and harboured a transmembrane domain mutation. Conclusion Mutations in TP53 and truncating mutations in KMT2D are generally present prior to treatment and will be investigated as biomarkers of treatment failure. Additional mutations are not always present at diagnosis, but their emergence can be detected in ctDNA and relapsed tissue, specifically mutations in MS4A1. As mutations in MS4A1 attenuate rituximab binding and are recurrently associated with clonal expansion, they likely impart a selective advantage and lead to resistance against anti-CD20 antibodies. Disclosures Michaud: Epizyme: Employment. Daigle:Epizyme: Employment. Jain:Kite/Gilead: Consultancy. Kuruvilla:Roche: Honoraria; Astra Zeneca: Honoraria; Novartis: Honoraria; Merck: Honoraria; Karyopharm: Honoraria; Gilead: Honoraria; Celgene: Honoraria; BMS: Honoraria; Amgen: Honoraria; Seattle Genetics: Consultancy; Roche: Consultancy; Merck: Consultancy; Karyopharm: Consultancy; Gilead: Consultancy; Janssen: Research Funding; Roche: Research Funding; BMS: Consultancy; Abbvie: Consultancy; Seattle Genetics: Honoraria; Janssen: Honoraria. Assouline:Abbvie: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Speakers Bureau; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria, Speakers Bureau. Scott:NanoString: Patents & Royalties: Named inventor on a patent licensed to NanoSting [Institution], Research Funding; Celgene: Consultancy; Roche/Genentech: Research Funding; Janssen: Consultancy, Research Funding. Johnson:BD Biosciences: Other: Provided a significant proportion of the antibodies used in this project free of cost.; Merck: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Abbvie: Consultancy, Employment, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Consultancy, Employment, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel fees, gifts, and others, Research Funding; Seattle Genetics: Honoraria; Lundbeck: Employment, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel fees, gifts, and others, Research Funding.

MicroRNAs are Related to Rituximab in Combination with Cyclophosphamide, Doxorubicin, Vincristine, and Prednisone Resistance in Patients with Diffuse Large B-cell Lymphoma

Aim: Rituximab in combination with cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) treatment failure is a rigorous problem in patients with diffuse large B-cell lymphoma (DLBCL), which usually predicts poor survival. The study explored the association of microRNAs with R-CHOP resistance in order to find reliable predictive factors and novel therapeutic targets. Methods: Forty-five newly diagnosed cases with DLBCL were administered with R-CHOP regimen. Thirty-three of them were divided into the sensitive group and 12 of them into the resistant group based on their response to the treatment. Both microRNAs and gene expression profilings were examined with microarray in these patients. Results: Six microRNAs were found to have significant difference between R-CHOP sensitive and resistant groups, including microRNA-9, microRNA-146a, microRNA-363, microRNA-488, microRNA-548d-3p, and microRNA-219-1-3p (P 1). Multivariate analysis showed that both microRNA-146a and microRNA-548d-3p were inversely correlated with resistance while microRNA-363 and microRNA-219-1-3p were directly correlated with resistance. Although both molecular subtypes based on cellular origin (Pearson correlation = 0.368, P = 0.023) and multiple extranodal involvement (Pearson correlation = 0.352, P = 0.030) manifested the association with R-CHOP resistance, these specific microRNAs remained independent predictors of clinical outcome in multivariate analysis. In addition, microRNA-146a was proved to have linkages with multiple extranodal involvements. Molecular subtypes based on a cellular origin were not verified to correlate with specific microRNAs. These specific microRNAs could predict resistance in 92.1% of patients in the present study. Conclusion: The expression of specific microRNAs may serve as useful biomarker for prediction of response to R-CHOP therapy in patients with DLBCL.

CD20 mutations involving the rituximab epitope are rare in diffuse large B-cell lymphomas and are not a significant cause of R-CHOP failure

Rituximab binds an epitope on the CD20 antigen, encompassed in exon 5 of the MS4A1 gene. We sequenced this region and correlated the presence of mutations with CD20 protein expression and response to R-CHOP in patients with diffuse large B-cell lymphoma: 264 diagnostic biopsies and 15 biopsies taken at the time of relapse were successfully sequenced. CD20 mutations involving the rituximab epitope were detected in only 1/264 (0.4%) and 1/15 (6%) of the biopsies taken at diagnosis and relapse, respectively. No polymorphic sequence variants were detected in this region. Three patients had malignant cells that were CD20 protein-positive at diagnosis but CD20-negative at relapse. Thus, CD20 mutations involving the rituximab epitope are rare in both de novo and relapsed diffuse large B-cell lymphoma, and do not represent a significant cause of R-CHOP resistance. CD20 protein-negative relapses occur after R-CHOP therapy but their clinical relevance is unknown.