Faculty Bibliography

Introduction: Inappropriate activation of Wnt/beta-catenin signaling plays a role in some cancers. beta-catenin (beta-cat) levels in the cell can be regulated by a cadherin-mediated sequestration into membrane-bound and free cytosolic pools, with the later translocating to the nucleus and driving TCF-mediated transcriptional activity following Wnt signal transduction. While sequencing has shown that MM lacks the mutations that typically lead to constitutive beta-cat activation seen in other cancers, we and others have demonstrated that Wnt/beta-catenin signaling is nonetheless activated in MM and can regulate MM growth. The mechanism driving beta-cat stabilization and activation in MM is unclear. E- and N-cadherin (N-cad) expression is elevated in MM compared to plasma cells from healthy donors. We hypothesized that that cadherins can regulate Wnt/beta-catenin signaling in MM.
Material(s) and Method(s): We detected different forms of beta-cat expression in a panel of human MM cell lines (HMCLs) and CD138 PC from MM patients by several approaches. Cadherin gain- or loss-of-function MM models were produced by expressing wild-type N-cad in MMS1 and ARP1 (lack endogenous N-cadherin expression) using a lentiviral system to create stable cell lines (N-Cad/MMS1 and N-cad/ARP1) and empty vector control (EV/MMS1, and EV-ARP1). We knocked down N-cadherin in the JJN3 cell line expressing high level of endogenous N-cadherin using shRNA specific for N-cad (shNcad/JJN3) or scrambled control shRNA (shCont/JJN3) by lentiviral-mediated transfection. We used a TCF reporter system to evaluate beta-cat transcriptional activity as previously described.
Result(s): We surveyed 25 HMCLs and CD138-selected plasma cells from 72 newly diagnosed MM for active beta-cat with an antibody that specifically recognizes the unphosphorylated active form of beta-cat. Higher levels of cytosolic and/or nuclear beta-cat protein were seen in 13 of 25 (52%) HMCLs and 36 of 72 (50%) primary MM PC. Correlation of beta-cat protein levels with global mRNA expression levels in primary PC revealed significant correlation with only one gene, CDH2 (N-cad). Remarkably, those primary MM with high beta-cat levels but low CDH2 levels expressed high levels of E-cadherin/CHD1 mRNA. This posed the question of whether CDH2 is a direct target of TCF/beta-cat transcriptional activity or whether high levels of CDH2 lead to increased levels of beta-cat protein via sequestration. Both CDH2 mRNA and protein were correlated with beta-cat protein but not beta-cat mRNA in 23/25 HMCLs. Co-immunoprecipitation revealed that N-cad and beta-cat complexes could be identified in HMCLs and primary MM. Consistent with N-cad-mediated stabilization of beta-cat both total and unphosphorylated beta-cat levels and TCF activity were significantly elevated in N-cad/MMS1 and N-Cad/ARP1 cells relative to controls. In contrast, shRNA mediated knockdown of N-cad led to a loss of both N-cad and beta-cat protein levels and TCF-dependent transcription activity relative to controls. These findings provide evidence that beta-cat/TCF signaling can be regulated by N-cad in MM. CDH2 mRNA is significantly elevated in the MS and HY subgroups of MM. To search for a potential mechanism of CDH2 transcriptional regulation in MS MM, we compared TCF activity and beta-cat protein levels in MS versus non-MS HMCLs. TCF activity and active beta-cat were elevated in MS versus non-MS forms of MM and B-cell lymphoma lacking N-cadherin. To determine if MMSET is required to up-regulate N-cad expression, we depleted the full-length MMSET protein in KMS11 cells. The results revealed a dramatic loss of total and unphosphorylated beta-cat protein, but not mRNA, and loss of both CDH2 mRNA and protein relative to controls. These data suggest that MMSET can regulate the transcription of the CDH2 gene. MMS1 and ARP1 cells stably expressing N-cad exhibited enhanced adhesion to bone marrow stromal cells and decreased sensitivity to bortezomib (Bzb). In contrast, blocking N-cadherin-mediated adhesion by CDH2 shRNA increased sensitivity to Bzb. These results suggests that N-cad/beta-cat complexes can contribute to adhesion-mediated drug resistance in MM.
Conclusion(s): Taken together, these findings establish that beta-cat is stabilized by N-cadherin-, and likely E-cadherin-, adhesins junction formation in MM. This in turn leads to an increased pool of beta-cat that can drive TCF transcriptional activation as well participate in cadherin-mediated cell adhesion and drug resistance. Disclosures: Davies: Amgen: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Roche: Consultancy, Honoraria. Morgan: BMS: Membership on an entity's Board of Directors or advisory committees; Jansen: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees. Walker: Bristol Myers Squibb: Research Funding; Sanofi: Speakers Bureau.
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Introduction: The incidence of multiple myeloma (MM) varies by ethnicity with Black patients approximately twice as likely to develop MM compared to White or Asian (Black: White males 2.9:1, females 2.2:1). The National Cancer Registration and Analysis Service (NCRAS) in 2015 reported the incidence of MM by ethnicity in England over 10 years to be 85.5% White; 5.4% Black; 3.6% Asian and 1.9% Other. Ethnic minorities have been reported to be under-represented in clinical trials partly because of socio-economic factors; however, it is unknown if these disparities exist in state funded health care systems where access to healthcare is free and should be equitable.
Method(s): Ethnicity, baseline demographics, progression-free survival (PFS) and overall survival (OS) were collected from patients enrolled into 1 ^st line UK academic transplant eligible (TE) and transplant non-eligible (TNE) - Myeloma IX, XI and XIV trials, and at 1 ^st relapse - Myeloma X and XII clinical trials. These trials enrolled from 2003 to 2021. The Myeloma XII and XIV (FiTNEss) trials are currently enrolling, all other trials have closed. Ethnicity was coded by White, Black, Asian and Other in line with Office for National Statistics (ONS) categories. Patients were enrolled across 120 centres covering a wide geographical distribution in the UK. These studies were designed to have permissive eligibility criteria to enrol as close to real world patients as possible. Baseline characteristics were summarised descriptively and comparisons made using the chi-squared test. Comparisons with population-level data used one-sample chi-squared tests. Survivor functions were estimated using the Kaplan-Meier method and were compared using the logrank test. Cox proportional hazards models with suitable interaction terms were used to test for heterogeneity. All tests were called significant at the 5% level.
Result(s): 7,291 patients were enrolled across 5 randomised controlled trials over 18 years. Overall, the ethnic distribution was White 93.8%, Black 2.2%, Asian 1.8%, Other 0.6% and unknown 1.6%. The skew to enrolment of White patients was more apparent in the TNE studies (Myeloma IX non-intensive: White 97.4%, Black 1.3%, Asian 0.4%; Myeloma XI non-intensive: White 94.5%, Black 1.8%, Asian 1.6%, Myeloma XIV: White 94.2%, Black 0%, Asian 3.2%). This was different to the incidence of myeloma cases across the UK with the difference most apparent in TNE studies (TE trials (observed vs NCRAS, P < 0.0001); TNE trials (observed vs NCRAS, P < 0.0001); 1 ^st relapse trials (observed vs NCRAS, P = 0.035)). Enrolment distribution by ethnicity was consistent over the 18 years, with no change in diversity over time despite there being an increase in UK non-white populations. In the Myeloma IX trial, there was no significant difference in age at enrolment; however, the performance status in Black patients was worse than non-Black (P = 0.045), there was fewer cytogenetic high risk Black patients (P = 0.007) and less ISS 1 Black patients vs non-Black (P = 0.0416). There were no demographic differences by ethnicity in the Myeloma XI trial. The outcomes of patients by PFS or OS by ethnic group was similar within each trial (figure 1). An overall improvement in OS for was demonstrated over time from Myeloma IX to the Myeloma XI trial with the incorporation of novel agents (median OS MRC-Myeloma IX: 48 months vs. median OS NCRI Myeloma-XI: 70 months, P < 0.0001). There was no evidence of heterogeneity of effect with respect to ethnicity (P = 0.456) suggesting all ethnic sub-groups benefited from this improvement in OS.
Conclusion(s): Enrolment of ethnic minorities into academic clinical trials in the UK was below that expected despite enrolling from >100 geographically spread sites and intended equitable access to healthcare. All ethnic groups derived an OS benefit from novel agents within trials that were not otherwise routinely available; however, a substantial proportion of ethnic minorities were not enrolled particularly TNE patients, thereby limiting their survival gains. Understanding causes of inequality and addressing these is a priority for the UK-MRA to ensure that all groups can potentially benefit, and trial results are representative of the UK population. [Formula presented] Disclosures: Popat: Abbvie, Takeda, Janssen, and Celgene: Consultancy; AbbVie, BMS, Janssen, Oncopeptides, and Amgen: Honoraria; Takeda: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES; GlaxoSmithKline: Consultancy, Honoraria, Research Funding; Janssen and BMS: Other: travel expenses. Craig: Celgene: Research Funding; Merck Sharpe & Dohme: Research Funding; Amgen: Research Funding; Takeda: Research Funding. Davies: Takeda: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Roche: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria. Cairns: Amgen: Research Funding; Merck Sharpe and Dohme: Research Funding; Takeda: Research Funding; Celgene / BMS: Other: travel support, Research Funding. Olivier: Merck Sharpe and Dohme: Research Funding; Takeda: Research Funding; Amgen: Research Funding; Celgene / BMS: Research Funding. Morgan: BMS: Membership on an entity's Board of Directors or advisory committees; Jansen: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees. Cook: BMS/Celgene: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Sanofi: Consultancy; Karyopharm: Consultancy; Amgen: Consultancy. OffLabel Disclosure: Revlimid and carfilzomib combinations are used off label
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Despite  improvements in outcome, 15-25% of newly diagnosed multiple myeloma (MM) patients have treatment resistant high-risk (HR) disease with a poor survival. The lack of a genetic basis for HR has focused attention on the role played by epigenetic changes. Aberrant expression and somatic mutations affecting genes involved in the regulation of tri-methylation of the lysine (K) 27 on histone 3 H3 (H3K27me3) are common in cancer. H3K27me3 is catalyzed by EZH2, the catalytic subunit of the Polycomb Repressive Complex 2 (PRC2). The deregulation of H3K27me3 has been shown to be involved in oncogenic transformation and tumor progression in a variety of hematological malignancies including MM. Recently we have shown that aberrant overexpression of the PRC2 subunit PHD Finger Protein 19 (PHF19) is the most significant overall contributor to HR status further focusing attention on the role played by epigenetic change in MM. By modulating both the PRC2/EZH2 catalytic activity and recruitment, PHF19 regulates the expression of key genes involved in cell growth and differentiation. Here we review the expression, regulation and function of PHF19 both in normal and the pathological contexts of solid cancers and MM. We present evidence that strongly implicates PHF19 in the regulation of genes important in cell cycle and the genetic stability of MM cells making it highly relevant to HR MM behavior. A detailed understanding of the normal and pathological functions of PHF19 will allow us to design therapeutic strategies able to target aggressive subsets of MM.

ABSTRACT:The summation of 20 years of biological studies and the comprehensive analysis of more than 1000 multiple myeloma genomes with data linked to clinical outcome has enabled an increased understanding of the pathogenesis of multiple myeloma in the context of normal plasma cell biology. This novel data have facilitated the identification of prognostic markers and targets suitable for therapeutic manipulation. The challenge moving forward is to translate this genetic and biological information into the clinic to improve patient care. This review discusses the key data required to achieve this and provides a framework within which to explore the use of response-adapted, biologically targeted, molecularly targeted, and risk-stratified therapeutic approaches to improve the management of patients with multiple myeloma.

Chromothripsis is detectable in 20-30% of newly diagnosed multiple myeloma (NDMM) patients and is emerging as a new independent adverse prognostic factor. In this study we interrogate 752 NDMM patients using whole genome sequencing (WGS) to investigate the relationship of copy number (CN) signatures to chromothripsis and show they are highly associated. CN signatures are highly predictive of the presence of chromothripsis (AUC = 0.90) and can be used identify its adverse prognostic impact. The ability of CN signatures to predict the presence of chromothripsis is confirmed in a validation series of WGS comprised of 235 hematological cancers (AUC = 0.97) and an independent series of 34 NDMM (AUC = 0.87). We show that CN signatures can also be derived from whole exome data (WES) and using 677 cases from the same series of NDMM, we are able to predict both the presence of chromothripsis (AUC = 0.82) and its adverse prognostic impact. CN signatures constitute a flexible tool to identify the presence of chromothripsis and is applicable to WES and WGS data.

BACKGROUND:Sex differences in the incidence and outcomes of several cancers are well established. Multiple myeloma (MM) is a malignant plasma cell dyscrasia accounting for 2% of all new cancer cases in the UK. There is a clear sex disparity in MM incidence, with 57% of cases in males and 43% in females. The mechanisms behind this are not well understood and the impact of sex on patient outcomes has not been thoroughly explored. PATIENTS AND METHODS/METHODS:We investigated the association of sex with baseline disease characteristics and outcome in 3894 patients recruited to the phase III UK NCRI Myeloma XI trial, in which treatment exposure to lenalidomide predominated. RESULTS:Females were significantly more likely to have the molecular lesions t(14;16) and del(17p) and were more likely to meet the cytogenetic classification of high-risk (HiR) or ultra-high-risk disease (UHiR). There was no difference in progression-free survival (PFS) or overall survival (OS) between the sexes in the overall population. CONCLUSION/CONCLUSIONS:Our data suggest that the genetic lesions involved in the initiation and progression of MM may be different between the sexes. Although females were more likely to have the poor prognosis lesions t(14;16) and del(17p), and were more likely to be assessed as having HiR or UHiR disease, this was not associated with reduced PFS or OS. In female patients the trial treatment may have been able to overcome some of the adverse effects of high-risk cytogenetic lesions. MicroAbstract Multiple myeloma (MM) is more common in males compared to females but the reasons behind this are not well understood and the impact of sex on patient outcomes is unclear. This study demonstrates fundamental differences in genetic lesions underlying the biology of MM between males and females. However, we found that progression-free survival and overall survival were the same in both sexes.

Not available.

Cell surface expression levels of GPRC5D, an orphan G protein-coupled receptor, are significantly higher on multiple myeloma (MM) cells, compared with normal plasma cells or other immune cells, which renders it a promising target for immunotherapeutic strategies. The novel GPRC5D-targeting T-cell redirecting bispecific antibody, talquetamab, effectively kills GPRC5D+ MM cell lines in the presence of T cells from both healthy donors or heavily pretreated MM patients. In addition, talquetamab has potent anti-MM activity in bone marrow (BM) samples from 45 patients, including those with high-risk cytogenetic aberrations. There was no difference in talquetamab-mediated killing of MM cells from newly diagnosed, daratumumab-naïve relapsed/refractory (median of 3 prior therapies), and daratumumab-refractory (median of 6 prior therapies) MM patients. Tumor cell lysis was accompanied by T-cell activation and degranulation, as well as production of pro-inflammatory cytokines. High levels of GPRC5D and high effector:target ratio were associated with improved talquetamab-mediated lysis of MM cells, whereas an increased proportion of T cells expressing PD-1 or HLA-DR, and elevated regulatory T-cell (Treg) counts were associated with suboptimal killing. In cell line experiments, addition of Tregs to effector cells decreased MM cell lysis. Direct contact with bone marrow stromal cells also impaired the efficacy of talquetamab. Combination therapy with daratumumab or pomalidomide enhanced talquetamab-mediated lysis of primary MM cells in an additive fashion. In conclusion, we show that the GPRC5D-targeting T-cell redirecting bispecific antibody talquetamab is a promising novel antimyeloma agent. These results provide the preclinical rationale for ongoing studies with talquetamab in relapsed/refractory MM.