B-cell Cancers Research Articles

Cancer Incidence among Marines and Navy Personnel and Civilian Workers Exposed to Industrial Solvents in Drinking Water at US Marine Corps Base Camp Lejeune: A Cohort Study.

Drinking water at US Marine Corps Base Camp Lejeune, North Carolina, was contaminated with trichloroethylene and other industrial solvents from 1953 to 1985. A cohort cancer incidence study was conducted of Marines/Navy personnel who began service and were stationed at Camp Lejeune () or Camp Pendleton, California () between 1975 and 1985 and civilian workers employed at Camp Lejeune () or Camp Pendleton () between October 1972 and December 1985. Camp Pendleton's drinking water was not contaminated with industrial solvents. Individual-level information on primary invasive cancers and in situ bladder cancer diagnosed between 1996 and 2017 was obtained from 54 US cancer registries. Proportional hazards regression was used to calculate adjusted hazard ratios (aHRs) comparing cancer incidence between the Camp Lejeune and Camp Pendleton cohorts, adjusted for sex, race, education, and rank (or blue-collar work), with age as the time variable. Precision of aHRs was evaluated using the 95% confidence interval (CI) ratio (CIR). Cancers among Camp Lejeune Marines/Navy personnel and civilian workers totaled 12,083 and 1,563, respectively. Cancers among Camp Pendleton Marines/Navy personnel and civilian workers totaled 12,144 and 1,416, respectively. Compared with Camp Pendleton, Camp Lejeune Marines/Navy personnel had aHRs with CIRs for all myeloid cancers (; 95% CI: 1.03, 1.49), acute myeloid leukemia (; 95% CI: 1.03, 1.85), myelodysplastic and myeloproliferative syndromes (; 95% CI: 1.07, 2.62), polycythemia vera (; 95% CI: 0.94, 2.11), and cancers of the esophagus (; 95% CI: 1.03, 1.56), larynx (; 95% CI: 0.98, 1.50), soft tissue (; 95% CI: 0.92, 1.59), and thyroid (; 95% CI: 1.03, 1.45). Lymphoma subtypes mantle cell and marginal zone B-cell and lung cancer subtypes adenocarcinoma and non-small cell lung cancer also had aHRs with CIRs . Compared with Camp Pendleton, Camp Lejeune civilian workers had aHRs with CIRs for all myeloid cancers (; 95% CI: 0.83, 2.36), squamous cell lung cancer (; 95% CI: 1.10, 2.41), and female breast (; 95% CI: 0.97, 1.52) and ductal cancer (; 95% CI: 1.02, 1.71). Increased risks of several cancers were observed among Marines/Navy personnel and civilian workers exposed to contaminated drinking water at Camp Lejeune compared with Camp Pendleton. https://doi.org/10.1289/EHP14966.

Insights into the Gene Expression Profile of Classical Hodgkin Lymphoma: A Study towards Discovery of Novel Therapeutic Targets.

Classical Hodgkin lymphoma (cHL) is a common B-cell cancer and a significant health concern, especially in Western and Asian countries. Despite the effectiveness of chemotherapy, many relapse cases are being reported, highlighting the need for improved treatments. This study aimed to address this issue by discovering biomarkers through the analysis of gene expression data specific to cHL. Additionally, potential anticancer inhibitors were explored to target the discovered biomarkers. This study proceeded by retrieving microarray gene expression data from cHL patients, which was then analyzed to identify significant differentially expressed genes (DEGs). Functional and network annotation of the upregulated genes revealed the active involvement of matrix metallopeptidase 12 (MMP12) and C-C motif metallopeptidase ligand 22 (CCL22) genes in the progression of cHL. Additionally, the mentioned genes were found to be actively involved in cancer-related pathways, i.e., oxidative phosphorylation, complement pathway, myc_targets_v1 pathway, TNFA signaling via NFKB, etc., and showed strong associations with other genes known to promote cancer progression. MMP12, topping the list with a logFC value of +6.6378, was selected for inhibition using docking and simulation strategies. The known anticancer compounds were docked into the active site of the MMP12 molecular structure, revealing significant binding scores of -7.7 kcal/mol and -7.6 kcal/mol for BDC_24037121 and BDC_27854277, respectively. Simulation studies of the docked complexes further supported the effective binding of the ligands, yielding MMGBSA and MMPBSA scores of -78.08 kcal/mol and -82.05 kcal/mol for MMP12-BDC_24037121 and -48.79 kcal/mol and -49.67 kcal/mol for MMP12-BDC_27854277, respectively. Our findings highlight the active role of MMP12 in the progression of cHL, with known compounds effectively inhibiting its function and potentially halting the advancement of cHL. Further exploration of downregulated genes is warranted, as associated genes may play a role in cHL. Additionally, CCL22 should be considered for further investigation due to its significant role in the progression of cHL.

Tuning CAR T-cell therapies for efficacy and reduced toxicity

Chimeric antigen receptor (CAR) T-cell therapies are a standard of care for certain relapsed or refractory B-cell cancers. However, many patients do not respond to CAR T-cell therapy or relapse later, short- and long-term toxicities are common, and current CAR T-cell therapies have limited efficacy for solid cancers. The gene engineering inherent in CAR T-cell manufacture offers an unprecedented opportunity to control cellular characteristics and design products that may overcome these limitations. This review summarises available methods to “tune” CAR T-cells for optimal efficacy and safety. The components of a typical CAR, and the modifications that can influence CAR T-cell function are discussed. Methods of engineering passive, inducible or autonomous control mechanisms into CAR T-cells, allowing selective limitation or enhancement of CAR T-cell activity are reviewed. The impact of manufacturing processes on CAR T-cell function are considered, including methods of limiting CAR T-cell terminal differentiation and exhaustion, and the use of specific T-cell subsets as the CAR T starting material. We discuss the use of multicistronic transgenes and multiplexed gene editing. Finally, we highlight the need for innovative clinical trial designs if we are to make the most of the opportunities offered by CAR T-cell therapies.

Abstract PO-035: Genome-wide CRISPR knockout screen identifies sialylation as a tumor suppressive mechanism in B-cell malignancies

Abstract Ba/F3 is a murine pro-B cell line that is dependent on interleukin-3 (IL-3) for its survival and proliferation. It has been widely used for identifying oncogenes and mechanisms of drug-resistance. Using this cell line, we conducted a genome-wide CRISPR knockout screen to identify genes whose loss can confer IL-3 independence, hence may be implied as tumor suppressor genes (TSGs). We identified several genes that map to human chromosome 6q, a frequent deletion hotspot in B-cell malignancies, that may act as TSGs. One of these putative novel TSGs is Slc35a1, which encodes the membrane solute carrier that facilitates the transport of nucleotide sugar (CMP-sialic acid) into the Golgi apparatus for subsequent sialylation. Interestingly, in addition to Slc35a1, pathway analysis of hits from the CRISPR screen identified several genes in the sialic acid metabolism pathway, Nans, Cmas, and St3gal5. We confirmed that their silencing led to decreased protein sialyation and could confer IL-3-independent cell survival and growth in Ba/F3 cells. We continued to characterize Slc35a1 since its homozygous and heterozygous deletions are seen in 7-40% of different types of B-cell malignancies, including approximately 40% of patients with Diffuse Large B-cell Lymphoma. Slc35a1 deletion in murine and human cell-lines conferred cytokine-independent growth. Tail-vein injection of Slc35a1-silenced Ba/F3 cells resulted in allograft tumor growth presenting with splenomegaly and lymphadenopathy. Using Maackia amurensis lectin II (MAL II) to pull down sialylated proteins for mass spectrometry, we identified proteins that were differentially sialylated in Slc35a1 wild-type and knockout cells, among which are the α and β subunits of the integrin receptor, lymphocyte functional antigen 1 (LFA-1). As integrin desialylation can promote its constitutive activation, we are currently studying the impact of LFA-1 sialylation on B-cell function and transformation. We have also developed mouse models with B-cell specific ablation of Nans and Slc35a1 to further evaluate the role of sialylation on B-cell development and tumorigenesis in vivo. Overall, our study demonstrates that sialylation may function as a tumor suppressive mechanism and serve as a therapeutic target in B-cell cancers. Citation Format: Namratha Sheshadri, Rongrong Li, Muhammad Usama Tariq, Jianliang Shen, Jaeyong Jung, Junrong Yan, Kevin Lu, Zhiyuan Shen, Ping Xie, Wei-Xing Zong. Genome-wide CRISPR knockout screen identifies sialylation as a tumor suppressive mechanism in B-cell malignancies [abstract]. In: Proceedings of the Fourth AACR International Meeting on Advances in Malignant Lymphoma: Maximizing the Basic-Translational Interface for Clinical Application; 2024 Jun 19-22; Philadelphia, PA. Philadelphia (PA): AACR; Blood Cancer Discov 2024;5(3_Suppl):Abstract nr PO-035.

Cardiotoxic profiles of CAR-T therapy and bispecific T-cell engagers in hematological cancers

BackgroundChimeric antigen receptor (CAR) T-cell therapy and bispecific T-cell engagers, which redirect T-cells to tumor antigens, have immensely benefitted patients with relapsed/refractory B-cell cancers. How these therapies differ in cardiotoxicity is underexplored. We used the World Health Organization pharmacovigilance database, VigiBase, to compare cardiotoxicity profiles between CD19-targeted CAR-T therapy and blinatumomab (a CD19/CD3-targeted bispecific T-cell engager).MethodsSafety reports in VigiBase were filtered for diffuse large B-cell lymphoma (DLBCL, n = 17,479) and acute lymphocytic leukemia (ALL, n = 28,803) for all adverse reactions. Data were further filtered for patients taking CAR-T therapy or blinatumomab. Reporting odds ratios (ROR) and fatality rates were compared between CAR-T cell products (e.g. tisagenlecleucel and axicabtagene ciloleucel), and between CAR-T therapy and blinatumomab.ResultsTisagenlecleucel is associated with cardiac failure (IC025 = 0.366) with fatality rates of 85.7% and 80.0% in DLBCL and pediatric ALL patients respectively. For DLBCL patients, axicabtagene ciloleucel has greater reporting for hypotension than tisagenlecleucel (ROR: 2.54; 95% CI: 1.28–5.03; p = 0.012), but tisagenlecleucel has higher fatality rates for hypotension than axicabtagene ciloleucel [50.0% (tisagenlecleucel) vs 5.6% (axicabtagene ciloleucel); p < 0.001]. Blinatumomab and tisagenlecleucel have similar fatality rates for hypotension in pediatric ALL patients [34.7% (tisagenlecleucel) vs 20.0% (blinatumomab); p = 0.66].ConclusionsTisagenlecleucel is associated with severe and fatal adverse cardiac events, with higher fatality rates for hypotension compared to axicabtagene ciloleucel in DLBCL patients, but similar hypotension fatality rates compared to blinatumomab in pediatric ALL patients. Effective management necessitates experienced physicians, including cardio-oncologists, skilled in interdisciplinary approaches to manage these toxicities.

IL-27-engineered CAR.19-NK-92 cells exhibit enhanced therapeutic efficacy

Chimeric antigen receptor (CAR) engineering of natural killer (NK) cells has shown promising results in early-phase clinical studies. However, advancing CAR-NK cell therapeutic efficacy is imperative. In this study, we investigated the impact of a fourth-generation CD19-targeted CAR (CAR.19) coexpressing IL-27 on NK-92 cells. We observed a significant improvement in NK-92 cell proliferation and cytotoxicity activity against B-cell cancer cell lines, both in vitro and in a xenograft mouse B-cell lymphoma model. Our systematic transcriptome analysis of the activated NK-92 CAR variants further supports the potential of IL-27 in fourth-generation CARs to overcome limitations of NK cell-based targeted tumor therapies by providing essential growth and activation signals. Integrating IL-27 into CAR-NK cells emerges as a promising strategy to enhance their therapeutic potential and elicit robust responses against cancer cells. These findings contribute substantially to the mounting evidence supporting the potential of fourth-generation CAR engineering in advancing NK cell-based immunotherapies.

Expanding the role of CAR T-cell therapy: From B-cell hematological malignancies to autoimmune rheumatic diseases.

Chimeric antigen receptor (CAR) T-cell therapy is a form of immunotherapy where the lymphocytes, mostly T-cells, are redirected to specifically recognize and eliminate a target antigen by coupling them with CARs. The binding of CAR and target cell surface antigens leads to vigorous T cell activation and robust anti-tumor immune responses. Areas of implication of CAR T-cell therapies include mainly hematological malignancies (i.e., advanced B-cell cancers); however, recent studies have proven the unprecedented success of the new immunotherapy also in autoimmune rheumatic diseases. We aim to review the recent advances in CAR T-cell therapies in rheumatology but also to address the limitations of their use in the real clinical practice based on the data on their efficacy and safety.

Abstract LB198: The PAX5 oncogene encodes circular RNA products involved in B cell cancer processes

Abstract Introduction: B-cell cancers represent some of the most prevalent hematological lesions in adult and children. B-cell cancers are also notable for their malignancy and resistance to drug therapies. Our group studies B-cell oncogenes and recently discovered that the prominent PAX5 oncogene, which usually encodes transcription factors, also generates non-coding circular RNA transcripts. Circular RNAs (circRNAs) represent a new class of gene products involved in many biological processes and cancer disease. Due to their innate ability to bind and modulate co-interacting proteins and microRNAs (miRs), circRNAs represent new signaling avenues in cancer biology. Hypothesis: Given that products from the PAX5 oncogene are important regulators of B-cell cancers, we hypothesized that PAX5 circRNAs (circPAX5) are also involved in B-cell oncogenesis. Objective: We therefore set out to study circPAX5 products, and their co-interacting miRs, in B-cell cancers. Results: Using a series of B-cell cancer models and clinical samples, we first profiled the expression of circPAX5 products and found that B-cell leukemias overexpress circPAX5 where its predominant circRNA isoform consisted of exons 2 to 5 sequences of the PAX5 locus. To establish a functional role of circPAX5 on cancer processes, we evaluated B-cell proliferation and chemosensitivity in cancer models expressing conditioned levels of circPAX5. Interestingly, we found that the suppression of circPAX5 levels resulted in the alteration of cancer growth rates, which were dependent upon B-cell differentiation state and population subtype. Mechanistically, we also found that circPAX5 interacts with specific miRs, which were profiled by circRNA precipitation and deep sequencing. Selected sponged miRs were then studied by bio-informatic analyses and mapped to downstream mRNA targets and B-cell cancer pathways. Conclusions: Altogether, our findings uncover PAX5 circular products, which are involved in B-cell cancer processes and could potentially represent a new cancer pathway targeted for therapeutic and/or diagnostic strategies in B-cell cancer lesions. Citation Format: Danick Martin, Brandon Hannay, Farrah McGraw, Alexis Martin, Vanessa Veilleux, Nicholas Finn, Gilles A. Robichaud. The PAX5 oncogene encodes circular RNA products involved in B cell cancer processes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB198.

To battle B-cell cancers, drugmakers are going beyond the covalent bond

To battle B-cell cancers, drugmakers are going beyond the covalent bond

Blocking Orai1 constitutive activity inhibits B-cell cancer migration and synergistically acts with drugs to reduce B-CLL cell survival

Orai1 channel capacity to control store-operated Ca2+ entry (SOCE) and B-cell functions is poorly understood and more specifically in B-cell cancers, including human lymphoma and leukemia. As compared to normal B-cells, Orai1 is overexpressed in B-chronic lymphocytic leukemia (B-CLL) and contributes in resting B-CLL to mediate an elevated basal Ca2+ level through a constitutive Ca2+ entry, and in BCR-activated B-cell to regulate the Ca2+ signaling response. Such observations were confirmed in human B-cell lymphoma and leukemia lines, including RAMOS, JOK-1, MEC-1 and JVM-3 cells. Next, the use of pharmacological Orai1 inhibitors (GSK-7975 A and Synta66) blocks constitutive Ca2+ entry and in turn affects B-cell cancer (primary and cell lines) survival and migration, controls cell cycle, and induces apoptosis through a mitochondrial and caspase-3 independent pathway. Finally, the added value of Orai1 inhibitors in combination with B-CLL drugs (ibrutinib, idelalisib, rituximab, and venetoclax) on B-CLL survival was tested, showing an additive/synergistic effect including in the B-cell cancer lines. To conclude, this study highlights the pathophysiological role of the Ca2+ channel Orai1 in B-cell cancers, and pave the way for the use of ORAI1 modulators as a plausible therapeutic strategy.

Cancer Treatment Disparities in People With HIV in the United States, 2001-2019.

People with HIV (PWH) have worse cancer outcomes, partially because of inequities in cancer treatment. We evaluated cancer treatment disparities among PWH, including an assessment of changes in disparities over time. We used data from the HIV/AIDS Cancer Match Study, a population-based HIV and cancer registry linkage to examine diffuse large B-cell lymphoma (DLBCL), Hodgkin lymphoma (HL), and cancers of the cervix, lung, anus, prostate, colon, and female breast. Outcomes included receipt of (1) any cancer treatment and (2) standard therapy among patients with local-stage cancer. We assessed associations between HIV and each outcome by estimating adjusted prevalence odds ratios (aORs) with 95% CI and trends over time. We identified predictors of nonreceipt of cancer treatment in PWH. From 2001 to 2019, compared with people with cancer without HIV (n = 2,880,955), PWH (n = 16,334) were more likely to not receive cancer treatment for cervical cancer (aOR, 2.03 [95% CI, 1.52 to 2.70]), DLBCL (aOR, 1.53 [95% CI, 1.38 to 1.70]), HL (aOR, 1.39 [95% CI, 1.19 to 1.63]), lung cancer (aOR, 1.79 [95% CI, 1.65 to 1.93]), prostate cancer (aOR, 1.32 [95% CI, 1.21 to 1.44]), colon cancer (aOR, 1.73 [95% CI, 1.43 to 2.08]), and breast cancer (aOR, 1.38 [95% CI, 1.07 to 1.77]). Similar associations were observed in PWH with local-stage cancers although no difference was observed for anal cancers. The association between HIV and nonreceipt of cancer treatment significantly decreased over time for breast, colon, and prostate cancers (all P trend <.0001), but PWH remained less likely to receive treatment in 2014-2019 for DLBCL, cervix, and lung cancers. Among PWH, Black individuals, people who inject drugs, and those 65 years and older were less likely to receive cancer treatment. Disparities in receipt of cancer treatment persist for PWH in the United States in contemporary time periods. Solutions to address inequitable receipt of cancer treatment among PWH are urgently needed.

Molecular Insights into the Impact of Mutations on the Binding Affinity of Targeted Covalent Inhibitors of BTK.

Targeted covalent inhibitors (TCIs) have witnessed a significant resurgence in recent years, particularly in the kinase drug discovery field for treating diverse clinical indications. The inhibition of Bruton's tyrosine kinase (BTK) for treating B-cell cancers is a classic example where TCIs such as ibrutinib have had breakthroughs in targeted therapy. However, selectivity remains challenging, and the emergence of resistance mutations is a critical concern for clinical efficacy. Computational methods that can accurately predict the impact of mutations on inhibitor binding affinity could prove helpful in informing targeted approaches─providing insights into drug resistance mechanisms. In addition, such systems could help guide the systematic evaluation and impact of mutations in disease models for optimal experimental design. Here, we have employed in silico physics-based methods to understand the effects of mutations on the binding affinity and conformational dynamics of select TCIs of BTK. The TCIs studied include ibrutinib, acalabrutinib, and zanubrutinib─all of which are FDA-approved drugs for treating multiple forms of leukemia and lymphoma. Our results offer useful molecular insights into the structural determinants, thermodynamics, and conformational energies that impact ligand binding for this biological target of clinical relevance.

Statement of Retraction: Knockdown of zinc finger protein 267 suppresses diffuse large B-cell lymphoma progression, metastasis, and cancer stem cell properties

Statement of Retraction: Knockdown of zinc finger protein 267 suppresses diffuse large B-cell lymphoma progression, metastasis, and cancer stem cell properties

Enhancing CAR-T cells: unleashing lasting impact potential with phytohemagglutinin activation in in vivo leukemia model.

Chimeric antigen receptor T (CAR-T) cell therapy holds great promise as an innovative immunotherapeutic approach for cancer treatment. To optimize the production and application of CAR-T cells, we evaluated the in vivo stability and efficacy capacities of CAR-T cells developed under different conditions. In this study, CAR-T cells were activated using Phytohemagglutinin (PHA) or anti-CD3&anti-CD28 and were compared in an in vivo CD19+B-cell cancer model in mouse groups. Our results demonstrated that CAR-T cells activated with PHA exhibited higher stability and anti-cancer efficacy compared to those activated with anti-CD3&anti-CD28. Specifically, CAR19BB-T cells activated with PHA exhibited continuous proliferation and long-term persistence without compromising their anti-cancer efficacy. Kaplan-Meier survival analysis revealed prolonged overall survival in the CAR-T cell-treated groups compared to the only tumor group. Furthermore, specific LTR-targeted RT-PCR analysis confirmed the presence of CAR-T cells in the treated groups, with significantly higher levels observed in the CAR19BB-T (PHA) group compared to other groups. Histopathological analysis of spleen, kidney, and liver tissue sections indicated reduced inflammation and improved tissue integrity in the CAR-T cell-treated groups. Our findings highlight the potential benefits of using PHA as a co-stimulatory method for CAR-T cell production, offering a promising strategy to enhance their stability and persistence. These results provide valuable insights for the development of more effective and enduring immunotherapeutic approaches for cancer treatment. CAR-T cells activated with PHA may offer a compelling therapeutic option for advancing cancer immunotherapy in clinical applications.

A Comprehensive Review of Small-Molecule Inhibitors Targeting Bruton Tyrosine Kinase: Synthetic Approaches and Clinical Applications.

Bruton tyrosine kinase (BTK) is an essential enzyme in the signaling pathway of the B-cell receptor (BCR) and is vital for the growth and activation of B-cells. Dysfunction of BTK has been linked to different types of B-cell cancers, autoimmune conditions, and inflammatory ailments. Therefore, focusing on BTK has become a hopeful approach in the field of therapeutics. Small-molecule inhibitors of BTK have been developed to selectively inhibit its activity and disrupt B-cell signaling pathways. These inhibitors bind to the active site of BTK and prevent its phosphorylation, leading to the inhibition of downstream signaling cascades. Regulatory authorities have granted approval to treat B-cell malignancies, such as chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL), with multiple small-molecule BTK inhibitors. This review offers a comprehensive analysis of the synthesis and clinical application of conventional small-molecule BTK inhibitors at various clinical stages, as well as presents promising prospects for the advancement of new small-molecule BTK inhibitors.

Abstract B128: Cancer treatment inequities in people with HIV in the United States, 2001-2019

Abstract Background: People with HIV (PWH) are at increased risk of both AIDS-defining (i.e., Kaposi sarcoma, non-Hodgkin lymphoma, cervical cancer) and non-AIDS-defining cancers. Prior work with data from 1996-2010 reported that PWH with cancer in the US were less likely to receive cancer treatment. However, an updated analysis is warranted to see if the disparity in receipt of cancer treatment persists for PWH. Methods: We used data from the HIV/AIDS Cancer Match (HACM) Study, a population-based HIV and cancer registry linkage in 13 U.S. states to examine diffuse large B-cell lymphoma (DLBCL), Hodgkin-lymphoma (HL), and cancers of the cervix, lung, anal, prostate, colon, and breast. For each cancer type, we estimated adjusted prevalence odds ratios (aOR) and 95% confidence intervals using logistic regression to assess the relationship between HIV status and cancer treatment adjusted for race, age at cancer diagnosis, sex, cancer stage, year of cancer diagnosis and region. In addition, we used logistic regression to identify predictors of cancer treatment receipt in PWH by cancer site, including race, age at cancer diagnosis, sex, HIV mode of transmission, cancer stage, calendar year period of cancer diagnosis and region. Results: We evaluated 11,657 PWH with cancer and 2,687,946 patients with cancer without HIV. A total of 9,030 PWH with cancer received any cancer treatment (77.5%) compared to 2,218,200 individuals with cancer, without HIV (82.5%) who received any cancer treatment. HIV was associated with lower odds of receiving cancer treatment compared to people with cancer and no HIV for cervical cancer (aOR=0.46 95% CI: 0.35-0.60), DLBCL (0.55, 0.50-0.62), HL (0.64,0.53-0.76), lung cancer (0.57, 0.52-0.62), prostate cancer (0.74, 0.66-0.83), and colon cancer (0.60, 0.50-0.74). Non-Hispanic (NH)-Black PWH with lung cancer were less likely to receive cancer treatment compared to NH-White PWH. People who inject drugs (PWID), PWID/men who have sex with men (MSM) and heterosexual PWH were less likely to be treated for DLBCL, lung cancer and prostate cancer compared to MSM. In contrast, PWID were more likely to receive cancer treatment for anal cancer than MSM. For PWH with DLBCL, those diagnosed in 2011-2014 were 46% more likely to receive treatment (aOR=1.46, 1.00-2.12) compared to those diagnosed in 1996-2000. Conclusion: Inequities in receipt of cancer treatment persist for PWH in the US. We saw for some cancers, PWH had lower odds of receiving cancer treatment, even after controlling for important factors. Beginning in 2018, the National Comprehensive Cancer Network (NCCN) published cancer treatment guidelines explicit for PWH. Despite improvements in HIV-related treatment, inequitable receipt of cancer treatment will continue to prolong and exacerbate disparities among people with cancer with and without HIV. Citation Format: Jennifer K. McGee-Avila, Gita Suneja, Qianlai Luo, Marie Josephe Horner, Ann Rositch, Eric Engels, Meredith S. Shiels, Jessica Islam. Cancer treatment inequities in people with HIV in the United States, 2001-2019 [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr B128.

Hnrnpu mutations Are Haploinsufficient and Alter the Transcriptome of MYC-Driven Lymphomas

Introduction: Burkitt lymphoma (BL) is an aggressive B-cell cancer, characterized by translocations that juxtapose a potent immunoglobulin enhancer with the MYC oncogene. MYC translocations are also found in 10% of tumors with diffuse large B-cell lymphoma morphology. When a BCL2 translocation is also present, these high-grade B-cell lymphomas (HGBCL-DH- BCL2) have poor prognosis. While sustained MYC expression can promote cell activation and proliferation, it also has potent and acute effects on programmed cell death, which cancer cells must overcome in order to survive. Identification and functional characterization of common mutations that cooperate with MYC are thus important for understanding its role in pathobiology. Methods: Patient samples were obtained from an ongoing meta-analysis of mature B-cell neoplasms including unpublished data from the Lymphoma/Leukemia Molecular Profiling Project. Simple somatic mutations were identified from whole genome or exome sequencing data using an ensemble of variant callers. MYC rearrangements breakpoints were identified using GRIDSS and Manta. All functional studies were performed in an EBV+ BL cell line (Raji). HNRNPU mutations were introduced into cells using IDTs ALT-R CRISPR-Cas9 system, clonally isolated, and verified by sequencing. Subsequent RNA-sequencing was performed. Knockdown and overexpression experiments were performed using an HNRNPU expression vector or siRNA targeting endogenous HNRNPU. HNRNPU eCLIP in HepG2 and K562 cells were obtained from the ENCODE project consortium. Differential gene expression was analysed with DESeq2. Peak-calling and individual crosslink sites were detected using PureCLIP. Results: Within the sequencing data, we noted that several RNA binding proteins were commonly mutated in BL and HGBCL-DH- BCL2. Mutations affecting HNRNPU were identified in tumors from 11.6% of HGBL-DH- BCL2 and 5.6% of BL patients. These mutations were predicted to be inactivating but, unlike conventional tumor suppressor genes, an inactivating mutation on the other allele was never observed. HNRNPU mutations were significantly enriched in EBV+ BLs. The gene product (hnRNP U) is an RNA- and DNA-binding protein that plays a central role in gene expression regulation. To understand their biological effect in aggressive lymphomas, we introduced heterozygous inactivating mutations in the most affected region of HNRNPU. Clones with confirmed knockout exhibited reduced expression at the mRNA and protein level. Through gene expression analysis, comparing the parental to two mutant lines, we identified 615 differentially expressed genes (358 downregulated, 219 upregulated). Pathway enrichment analysis revealed reduced expression of genes in several relevant pathways such as MYC, TP53 and DNA damage response. This was consistent with our observation of reduced MYC protein in the mutant lines. A role of hnRNPU-in MYC modulation was further in experiments when HNRNPU knockdown reduced and overexpression increased MYC expression. Overexpression of hnRNP U also resulted in cellular stress and a decrease in cell proliferation. Using actinomycin D chase experiments, we found that hnRNPU loss leads to reduced MYC transcript stability. Crosslinking immunoprecipitation suggests that hnRNP U binds directly to the MYC transcript in poly G tracts in intron 1. This region is predicted to fold into G-quadruplexes, a secondary structure that can be bound by hnRNP U. HNRNPU mutations are only observed in tumors with an intact MYC locus rather than those with a rearrangement in intron 1. Taken together, these findings suggest that the region of MYC upstream of intron 1 may be relevant for HNRNPU-mediated modulation of MYC. Conclusion: HNRNPU mutations are novel recurrent driver mutations specifically within MYC translocated B-cell lymphomas. HNRNPU acts as a modulator of MYC expression, and the most common mutations are predicted to negatively impact this role. We propose a model where HNRNPU mutations moderate MYC expression, thus buffering MYC-induced apoptosis and proteotoxic stress. Further experiments to explore the role of HNRNPU binding on MYC expression and the potential role in buffering the proteotoxic stress associated with MYC translocations are ongoing. Insights into the mechanisms contributing to disease will support ongoing work to establish in vitro and in vivo models for future therapeutic investigations.

Engineering NK-CAR.19 cells with the IL-15/IL-15Rα complex improved proliferation and anti-tumor effect in vivo.

Natural killer 92 (NK-92) cells are an attractive therapeutic approach as alternative chimeric antigen receptor (CAR) carriers, different from T cells, once they can be used in the allogeneic setting. The modest in vivo outcomes observed with NK-92 cells continue to present hurdles in successfully translating NK-92 cell therapies into clinical applications. Adoptive transfer of CAR-NK-92 cells holds out the promise of therapeutic benefit at a lower rate of adverse events due to the absence of GvHD and cytokine release syndrome. However, it has not achieved breakthrough clinical results yet, and further improvement of CAR-NK-92 cells is necessary. In this study, we conducted a comparative analysis between CD19-targeted CAR (CAR.19) co-expressing IL-15 (CAR.19-IL15) with IL-15/IL-15Rα (CAR.19-IL15/IL15Rα) to promote NK cell proliferation, activation, and cytotoxic activity against B-cell leukemia. CAR constructs were cloned into lentiviral vector and transduced into NK-92 cell line. Potency of CAR-NK cells were assessed against CD19-expressing cell lines NALM-6 or Raji in vitro and in vivo in a murine model. Tumor burden was measured by bioluminescence. We demonstrated that a fourth- generation CD19-targeted CAR (CAR.19) co-expressing IL-15 linked to its receptor IL-15/IL-15Rα (CAR.19-IL-15/IL-15Rα) significantly enhanced NK-92 cell proliferation, proinflammatory cytokine secretion, and cytotoxic activity against B-cell cancer cell lines in vitro and in a xenograft mouse model. Together with the results of the systematic analysis of the transcriptome of activated NK-92 CAR variants, this supports the notion that IL-15/IL-15Rα comprising fourth-generation CARs may overcome the limitations of NK-92 cell-based targeted tumor therapies in vivo by providing the necessary growth and activation signals.

Intracellular BAPTA directly inhibits PFKFB3, thereby impeding mTORC1-driven Mcl-1 translation and killing MCL-1-addicted cancer cells

Intracellular Ca2+ signals control several physiological and pathophysiological processes. The main tool to chelate intracellular Ca2+ is intracellular BAPTA (BAPTAi), usually introduced into cells as a membrane-permeant acetoxymethyl ester (BAPTA-AM). Previously, we demonstrated that BAPTAi enhanced apoptosis induced by venetoclax, a BCL-2 antagonist, in diffuse large B-cell lymphoma (DLBCL). This finding implied a novel interplay between intracellular Ca2+ signaling and anti-apoptotic BCL-2 function. Hence, we set out to identify the underlying mechanisms by which BAPTAi enhances cell death in B-cell cancers. In this study, we discovered that BAPTAi alone induced apoptosis in hematological cancer cell lines that were highly sensitive to S63845, an MCL-1 antagonist. BAPTAi provoked a rapid decline in MCL-1-protein levels by inhibiting mTORC1-driven Mcl-1 translation. These events were not a consequence of cell death, as BAX/BAK-deficient cancer cells exhibited similar downregulation of mTORC1 activity and MCL-1-protein levels. Next, we investigated how BAPTAi diminished mTORC1 activity and identified its ability to impair glycolysis by directly inhibiting 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3) activity, a previously unknown effect of BAPTAi. Notably, these effects were also induced by a BAPTAi analog with low affinity for Ca2+. Consequently, our findings uncover PFKFB3 inhibition as an Ca2+-independent mechanism through which BAPTAi impairs cellular metabolism and ultimately compromises the survival of MCL-1-dependent cancer cells. These findings hold two important implications. Firstly, the direct inhibition of PFKFB3 emerges as a key regulator of mTORC1 activity and a promising target in MCL-1-dependent cancers. Secondly, cellular effects caused by BAPTAi are not necessarily related to Ca2+ signaling. Our data support the need for a reassessment of the role of Ca2+ in cellular processes when findings were based on the use of BAPTAi.

RIPK1 is aberrantly expressed in multiple B-cell cancers and implicated in the underlying pathogenesis

According to the latest epidemiology of the US, B-cell cancers account for > 3% of all new cancer cases and > 80% of non-Hodgkin lymphomas. However, the disease-modifying small molecular drug suitable for most B-cell cancers is still lacking. RIPK1 (receptor-interacting serine/threonine-protein kinase 1) has been observed to be dysregulated and implicated in the pathogenesis of multiple solid cancers, of which, however, the roles in blood cancers are quite unclear. In our study, to identify multi-function targets for B-cell cancer treatment, we reanalyzed a public transcriptomic dataset from the database of Gene Expression Omnibus, which includes CD19+ B-cell populations from 6 normal donors and patients of 5 CLL, 10 FL, and 8 DLBCL. After overlapping three groups (CLL vs. normal, FL vs. normal, and DLBCL vs. normal) of differentially expressed genes (DEGs), we obtained 69 common DEGs, of which 3 were validated by real-time quantitative PCR, including RIPK3, IGSF3, TGFBI. Interestingly, we found that the loss function of RIPK1 significantly increases the proliferation and viability of GM12878 cells (a normal human B lymphocyte cell line). Consistently, overexpression of RIPK1 in TMD8 and U2932 cells effectively inhibited cell proliferation and growth. More importantly, modifying RIPK1 kinase activity by a small molecule (such as necrostain-1, HOIPIN-1, etc.) alters the cell growth status of B-cell lymphoma, showing that RIPK1 exhibits anti-tumor activity in the context of B-cell lymphoma. Taken together, we consider that RIPK1 may be a potential target in the clinical application of B-cell lymphoma (including CLL, DLBCL, and FL) treatment.