Targeting glutaminase is therapeutically effective in ibrutinib-resistant mantle cell lymphoma

Mantle cell lymphoma (MCL) is an incurable B-cell non-Hodgkin lymphoma characterized by frequent relapses. The development of resistance to ibrutinib therapy remains a major challenge in MCL. We previously showed that glutaminolysis is associated with resistance to ibrutinib. In this study, we confirmed that glutaminase (GLS), the first enzyme in glutaminolysis, is overexpressed in ibrutinib-resistant MCL cells, and that its expression correlates well with elevated glutamine dependency and glutaminolysis. Furthermore, we discovered that GLS expression correlates with MYC expression and the functioning of the glutamine transporter ASCT2. Depletion of glutamine or GLS significantly reduced cell growth, while GLS overexpression enhanced glutamine dependency and ibrutinib resistance. Consistent with this, GLS inhibition by its specific inhibitor telaglenastat suppressed MCL cell growth both in vitro and in vivo. Moreover, telaglenastat showed anti-MCL synergy when combined with ibrutinib or venetoclax in vitro, which was confirmed using an MCL patient-derived xenograft model. Our study provides the first evidence that targeting GLS with telaglenastat, alone or in combination with ibrutinib or venetoclax, is a promising strategy to overcome ibrutinib resistance in MCL.

Abstract 3955: Targeting transcription elongation via CDK9 in mantle cell lymphoma patients with dual resistance to BTK inhibition and CAR T therapy

Introduction Clinical relapse following CD19 CAR T therapy after failure to BTK inhibitors (BTKi) is a novel and fast growing medical challenge in treating patients with mantle cell lymphoma (MCL). Thus, developing a novel therapy to overcome this BTKi-CAR T dual resistance (Dual-R) is an urgent need. Our unpublished data revealed MYC targets and cyclin-dependent kinase 9 (CDK9) are highly upregulated in the Dual-R compared to BTKi-R samples. CDK9 is a critical component of the positive transcription elongation factor b (P-TEFb) complex. Its inhibition induces acute decline of short-lived mRNA and proteins, especially MYC and MCL-1, in acute myeloid leukemia and diffuse large B-cell lymphoma. Therefore, we hypothesize that targeting CDK9 may turn off MYC-driven tumor survival and drug resistance. BAY-1251152 is a novel selective CDK9 inhibitor with nanomolar potency. However, whether it has the potential to overcome BTKi-CAR T dual resistance has not been assessed.

Methods To validate the correlation of MYC and CDK9 with drug resistance and clinical outcome, we performed whole transcriptomic profiling using primary patient samples. To assess the in vitro efficacy of BAY-1251152, we performed cell viability assay and cell apoptosis assay using MCL cell lines and primary patient samples and followed up with functional studies. furthermore, we assessed its in vivo efficacy using patient-derived xenograft (PDX) models derived from MCL patients including one with Dual-R.

Results The expression of MYC oncogene associates with ibrutinib resistance and Dual-R, and poor clinical outcome. CDK9 expression does not correlates with ibrutinib resistance but it does associate with Dual-R and poor clinical outcome in CAR T-relapsed patients. CDK9 inhibition by BAY-1251152 is highly potent in anti-MCL activity in MCL cell lines with low nanomolar range of IC50 (59.6-172.3 nM) by inducing robust cell apoptosis. BAY-1251152 induces dose and time-dependent CDK9 inhibition. A rapid decline of phosphorylation of RNA polymerase II, MYC, MCL-1, and Cyclin D1 can be observed as early as 2 hours. Furthermore, BAY-1251152 (10mg/kg, QW) significantly inhibited tumor growth (p = 0.000003) in a PDX model derived from a Dual-R patient without causing apparent toxicity in NSG mice. In addition, BAY-1251152 also significantly suppressed tumor growth in the PDX models derived from a BTKi-R patient (p=0.00015) and a BTKi-venetoclax dual-resistant patient (p=0.009).

Conclusion Our findings showed that targeting CDK9 by its specific inhibitor BAY-1251152 led to potent in vitro anti-MCL activity. BAY-1251152 induces fast CDK9 inhibition and rapid decline of MYC, MCL-1 and Cyclin D1 to induce robust cell death. BAY-1251152 is also potent in inhibiting tumor growth in PDX models. These data support that CDK9 is a promising target to overcome BTKi-CAR T dual resistance in MCL, which is in urgent need.

Citation Format: Vivian Changying Jiang, Lingzhi Li, Alexa Jordan, Yu Xue, Fangfang Yan, Joseph McIntosh, Yang Liu, Yuxuan Che, Yijing Li, Qingsong Cai, Angela Leeming, Lukas Simon, Zhongming Zhao, Jia Zhou, Michael Wang. Targeting transcription elongation via CDK9 in mantle cell lymphoma patients with dual resistance to BTK inhibition and CAR T therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3955.

Targeting FcγRIIB by antagonistic antibody BI-1206 improves the efficacy of rituximab-based therapies in aggressive mantle cell lymphoma

Inevitable relapses remain as the major therapeutic challenge in patients with mantle cell lymphoma (MCL) despite FDA approval of multiple targeted therapies and immunotherapies. Fc gamma receptors (FcγRs) play important roles in regulating antibody-mediated immunity. FcγRIIB, the unique immune-checkpoint inhibitory member of the FcγR family, has been implicated in immune cell desensitization and tumor cell resistance to the anti-CD20 antibody rituximab and other antibody-mediated immunotherapies; however, little is known about its expression and its immune-modulatory function in patients with aggressive MCL, especially those with multi-resistance. In this study, we found that FcγRIIB was ubiquitously expressed in both MCL cell lines and primary patient samples. FcγRIIB expression is significantly higher in CAR T-relapsed patient samples (p < 0.0001) compared to ibrutinib/rituximab-naïve, sensitive or resistant samples. Rituximab-induced CD20 internalization in JeKo-1 cells was completely blocked by concurrent treatment with BI-1206, a recombinant human monoclonal antibody targeting FcγRIIB. Combinational therapies with rituximab-ibrutinib, rituximab-venetoclax and rituximab-CHOP also induced CD20 internalization which was again effectively blocked by BI-1206. BI-1206 significantly enhanced the in vivo anti-MCL efficacy of rituximab-ibrutinib (p = 0.05) and rituximab-venetoclax (p = 0.02), but not the rituximab-CHOP combination in JeKo-1 cell line-derived xenograft models. In patient-derived xenograft (PDX) models, BI-1206, as a single agent, showed high potency (p < 0.0001, compared to vehicle control) in one aggressive PDX model that is resistant to both ibrutinib and venetoclax but sensitive to the combination of rituximab and lenalidomide (the preclinical mimetic of R² therapy). BI-1206 sensitized the efficacy of rituximab monotherapy in a PDX model with triple resistance to rituximab, ibrutinib and CAR T-therapies (p = 0.030). Moreover, BI-1206 significantly enhanced the efficacy of the rituximab-venetoclax combination (p < 0.05), which led to long-term tumor remission in 25% of mice. Altogether, these data support that targeting this new immune-checkpoint blockade enhances the therapeutic activity of rituximab-based regimens in aggressive MCL models with multi-resistance.

Longitudinal single-cell profiling reveals molecular heterogeneity and tumor-immune evolution in refractory mantle cell lymphoma

The mechanisms driving therapeutic resistance and poor outcomes of mantle cell lymphoma (MCL) are incompletely understood. We characterize the cellular and molecular heterogeneity within and across patients and delineate the dynamic evolution of tumor and immune cell compartments at single cell resolution in longitudinal specimens from ibrutinib-sensitive patients and non-responders. Temporal activation of multiple cancer hallmark pathways and acquisition of 17q are observed in a refractory MCL. Multi-platform validation is performed at genomic and cellular levels in PDX models and larger patient cohorts. We demonstrate that due to 17q gain, BIRC5/survivin expression is upregulated in resistant MCL tumor cells and targeting BIRC5 results in marked tumor inhibition in preclinical models. In addition, we discover notable differences in the tumor microenvironment including progressive dampening of CD8+ T cells and aberrant cell-to-cell communication networks in refractory MCLs. This study reveals diverse and dynamic tumor and immune programs underlying therapy resistance in MCL.

Mindfulness-based stress reduction alters brain activity for breast cancer survivors with chronic neuropathic pain: preliminary evidence from resting-state fMRI

PURPOSE

Breast cancer continues to be the most commonly diagnosed cancer among Canadian women, with as many as 25-60% of women suffering from chronic neuropathic pain (CNP) as a pervasive consequence of treatment. While pharmacological interventions have shown limited efficacy for the management of CNP to date, psychological interventions, such as mindfulness-based stress reduction (MBSR), may be a promising alterative for improving pain-related problems. The purpose of this study was to use brain imaging methods to investigate this potential.

METHODS

Resting-state fMRI was used in female breast cancer survivors with CNP before and after an 8-week MBSR course (n = 13) and compared with a waitlist control group (n = 10).

RESULTS

Focusing on the default mode network, the most significant results show greater posterior cingulate connectivity with medial prefrontal regions post-MBSR intervention. Moreover, this change in connectivity correlated with reduced pain severity for the MBSR group.

CONCLUSIONS

These results provide empirical evidence of a change in the brain following MBSR intervention associated with changes in the subjective experience of pain.

IMPLICATIONS FOR CANCER SURVIVORS

This study gives hope for a non-invasive method of easing the struggle of CNP in women following breast cancer treatment.

Abstract 5683: Single-cell RNA-seq reveals heterogeneity, clonal evolution and strategies to overcome ibrutinib-venetoclax dual resistance in mantle cell lymphoma

Introduction The clinical, pathological, genetic, and transcriptomic characteristics of mantle cell lymphoma (MCL) are extremely heterogeneous, and MCL patients frequently develop therapeutic resistance after frontline therapies. In this study, we performed longitudinal transcriptomic analysis on patient specimens at the single-cell level, aiming to understand the dynamic and complex cellular and molecular changes underlying therapeutic resistance and to identify potential targets to overcome dual resistance to ibrutinib and venetoclax.

Methods Single-cell RNA-seq was performed on sequential MCL patient specimens. Integrative computational approaches were employed to characterize the cellular and molecular basis of therapeutic resistance and clonal evolution. Bulk RNA sequencing, deep WES, and 17-color flow analysis of multiple patient cohorts were used to validate the novel findings. An orthotopic PDX model derived from one of the ibrutinib-venetoclax non-responders was used for further analysis and to investigate the in vivo efficacy of therapeutic agents against multiple actionable targets.

Results To dissect the inter- and intra-tumor heterogeneity underlying the therapeutic resistance, we performed sequential scRNA-seq analysis of 21 specimens (18,794 cells in total) collected from 3 ibrutinib responders and 2 ibrutinib-venetoclax non-responders along the course of ibrutinib and/or venetoclax treatments. The analysis revealed a high degree of inter- and intra-tumor heterogeneity with distinct cellular and transcriptomic profiling within and across ibrutinib-responders and ibrutinib-venetoclax non-responders. The observed transcriptomic evolution of cancer hallmarks associated with disease progression and therapeutic resistance were faithfully passed onto the orthotopic PDX model derived from one of the ibrutinib-venetoclax non-responders. We tracked the clinical ibrutinib-induced lymphocytosis at a single-cell level in ibrutinib responders and disease progression-associated clonal evolution in non-responders, which was validated by deep WES analysis. 17q gain in non-responders was further validated in a larger patient cohort. Our analysis revealed the reprogramming of tumor microenvironment and tumor immune evasion, which was further validated by 17-color flow analysis in a large cohort (n = 70). Inhibition of multiple actionable targets showed effective anti-MCL activity in the PDX model to overcome the ibrutinib-venetoclax dual resistance.

Conclusions This study demonstrates the potential of longitudinal single-cell transcriptomic analysis to reveal the molecular mechanisms underlying tumor heterogeneity, clonal evolution, disease progression, and therapeutic resistance, and to identify potential novel targets to circumvent therapeutic resistance in MCL and other diseases.

Citation Format: Changying Jiang, Shaojun Zhang, Yuanxin Wang, Rongjia Zhang, Yang Liu, Joseph McIntosh, Guangchun Han, Ruiping Wang, David Santos, Maria Badillo, Angela Leeming, Zhihong Chen, Kimberly Hartig, John Bigcal, Hun Lee, Raphael Steiner, Jorge Romaguera, Preetesh Jain, Krystle Nomie, Andy Futreal, Linghua Wang, Michael Wang. Single-cell RNA-seq reveals heterogeneity, clonal evolution and strategies to overcome ibrutinib-venetoclax dual resistance in mantle cell lymphoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5683.

A model morphology of the pulmonary acinus

A variation of a mathematical model of the structure of a pulmonary ventilatory unit is used to generate its internal ductal tree and associated alveolar architecture. The model unit comprises a space-filling block of regular polyhedra; ducts and alveoli were formed by opening specific common faces between polyhedra. The model employs a physically reasonable optimization strategy of maximizing gas exchange while minimizing the mean transit time to ventilate the ventilatory unit (assumed to be proportional to the mean path length) in order to create the ductal tree. The sensitivity of the global architecture to the competitive optimization parameters used and the tree structure are compared with independently published measurements. The study concludes that it is possible to model the detailed architecture of a unit using a simple space-invariant uniform modular structure for both alveoli and ductal parts. The close similarity between model and experimental measurement strongly suggests that the optimization used to create the unit is a likely one from a functional biological standpoint. The insensitivity of the architecture to the competition between the optimization parameters supports the belief that it is not important to consider the detailed measured size distribution of alveoli when considering how the large structure of the ventilatory unit is built up.

Modelling impact-initiated wave transmission through lung parenchyma in relation to the aetiology of exercise-induced pulmonary haemorrhage

Recently we proposed that exercise-induced pulmonary haemorrhage (EIPH) results from locomotory-impact-induced trauma by impact of the scapula on the chest wall during footfall and the consequent transmission of waves through the lung. A computational model has been developed to demonstrate that wave amplification and focusing occur in the dorsocaudal tip of the lung for waves originating on the anterior subscapular surface. The propagation of an acoustic wave was investigated in a simplified 2-dimensional representation of a vertical anterio-dorsal section of horse lung. It was demonstrated that a complicated pattern of waves is transmitted from the scapula to the dorsal region. Wave motion was characterised using the instantaneous rate of change of pressure with time (dp/dt) which is associated with lung injury. Due to wave reflection and focusing, dp/dt is transiently very high on the spinal and diaphragmatic lung walls, particularly in the vicinity of the dorsal tip. The model therefore predicts that lung injury may occur in the region in which EIPH is reported to originate.