Search

RNA splicing dysregulation underlies the onset and progression of cancers. In chronic lymphocytic leukemia (CLL), spliceosome mutations leading to aberrant splicing occur in ∼20% of patients. However, the mechanism for splicing defects in spliceosome-unmutated CLL cases remains elusive. Through an integrative transcriptomic and proteomic analysis, we discover that proteins involved in RNA splicing are posttranscriptionally upregulated in CLL cells, resulting in splicing dysregulation. The abundance of splicing complexes is an independent risk factor for poor prognosis. Moreover, increased splicing factor expression is highly correlated with the abundance of METTL3, an RNA methyltransferase that deposits N6-methyladenosine (m6A) on mRNA. METTL3 is essential for cell growth in vitro and in vivo and controls splicing factor protein expression in a methyltransferase-dependent manner through m6A modification-mediated ribosome recycling and decoding. Our results uncover METTL3-mediated m6A modification as a novel regulatory axis in driving splicing dysregulation and contributing to aggressive CLL. Significance: METTL3 controls widespread splicing factor abundance via translational control of m6A-modified mRNA, contributes to RNA splicing dysregulation and disease progression in CLL, and serves as a potential therapeutic target in aggressive CLL. See related commentary by Janin and Esteller, p. 176. This article is highlighted in the In This Issue feature, p. 171

In this review, we summarize the biological roles of methionine, methionine adenosyl transferase 2A (MAT2A) and S -adenosyl methionine (SAM) in methylation reactions during tumorigenesis. Newly emerged inhibitors targeting the methionine-MAT2A-SAM axis will be discussed.SAM is the critical and global methyl-donor for methylation reactions regulating gene expression, and in mammalian cells, it is synthesized by MAT2A using methionine. Recent studies have validated methionine and MAT2A as metabolic dependencies of cancer cells because of their essential roles in SAM biosynthesis. MAT2A inhibition leads to synthetic lethality in methylthioadenosine-phosphorylase (MTAP)-deleted cancers, which accounts for 15% of all cancer types. Of note, remarkable progress has been made in developing inhibitors targeting the methionine-MAT2A-SAM axis, as the first-in-class MAT2A inhibitors AG-270 and IDE397 enter clinical trials to treat cancer.The methionine-MAT2A-SAM axis plays an important role in tumorigenesis by providing SAM as a critical substrate for abnormal protein as well as DNA and RNA methylation in cancer cells. Targeting SAM biosynthesis through MAT2A inhibition has emerged as a novel and promising strategy for cancer therapy.

The ZUMA-7 (Efficacy of Axicabtagene Ciloleucel Compared to Standard of Care Therapy in Subjects With Relapsed/Refractory Diffuse Large B Cell Lymphoma) study showed that axicabtagene ciloleucel (axi-cel) improved event-free survival (EFS) compared with standard of care (SOC) salvage chemoimmunotherapy followed by autologous stem cell transplant in primary refractory/early relapsed diffuse large B-cell lymphoma (DLBCL); this led to its recent US Food and Drug Administration approval in this setting. We modeled a hypothetical cohort of US adults (mean age, 65 years) with primary refractory/early relapsed DLBCL by developing a Markov model (lifetime horizon) to model the cost-effectiveness of second-line axi-cel compared with SOC using a range of plausible long-term outcomes. EFS and OS were estimated from ZUMA-7. Outcome measures were reported in incremental cost-effectiveness ratios, with a willingness-to-pay (WTP) threshold of $150 000 per quality-adjusted life-year (QALY). Assuming a 5-year EFS of 35% with second-line axi-cel and 10% with SOC, axi-cel was cost-effective at a WTP of $150 000 per QALY ($93 547 per QALY). axi-cel was no longer cost-effective if its 5-year EFS was ≤26.4% or if it cost more than $972 061 at a WTP of $150 000. Second-line axi-cel was the cost-effective strategy in 73% of the 10 000 Monte Carlo iterations at a WTP of $150 000. If the absolute benefit in EFS is maintained over time, second-line axi-cel for aggressive relapsed/refractory DLBCL is cost-effective compared with SOC at a WTP of $150 000 per QALY. However, its cost-effectiveness is highly dependent on long-term outcomes. Routine use of second-line chimeric antigen receptor T-cell therapy would add significantly to health care expenditures in the United States (more than $1 billion each year), even when used in a high-risk subpopulation. Further reductions in the cost of chimeric antigen receptor T-cell therapy are needed to be affordable in many regions of the world.

Fig S1. SF3B1 mutant CLL samples had pervasive changes in 3’ splice site. Fig S2. Omics analyses identify widespread post-transcriptional upregulation of splicing factors in CLL. Fig S3. Abundance of spliceosome complexes and RNA-binding proteins are associated with clinical outcomes in CLL. Fig S4. METTL3 is consistently upregulated along with differential m6A modification on transcripts of RNA splicing process in CLL. Fig S5. KO or pharmacological inhibition of METTL3 impacts cell growth. Fig S6. KO or pharmacological inhibition of METTL3 impacts apoptosis, cell cycle, and splicing factor abundance. Fig S7. Splicing factors are either direct or indirect targets of METTL3. Fig S8. Validation of association between m6A and splicing factor abundance using dCasRx-METTL3.

RNA splicing dysregulation underlies the onset and progression of cancers. In chronic lymphocytic leukemia (CLL), spliceosome mutations leading to aberrant splicing occur in ∼20% of patients. However, the mechanism for splicing defects in spliceosome-unmutated CLL cases remains elusive. Through an integrative transcriptomic and proteomic analysis, we discover that proteins involved in RNA splicing are posttranscriptionally upregulated in CLL cells, resulting in splicing dysregulation. The abundance of splicing complexes is an independent risk factor for poor prognosis. Moreover, increased splicing factor expression is highly correlated with the abundance of METTL3, an RNA methyltransferase that deposits N6-methyladenosine (m6A) on mRNA. METTL3 is essential for cell growth in vitro and in vivo and controls splicing factor protein expression in a methyltransferase-dependent manner through m6A modification-mediated ribosome recycling and decoding. Our results uncover METTL3-mediated m6A modification as a novel regulatory axis in driving splicing dysregulation and contributing to aggressive CLL.Significance:METTL3 controls widespread splicing factor abundance via translational control of m6A-modified mRNA, contributes to RNA splicing dysregulation and disease progression in CLL, and serves as a potential therapeutic target in aggressive CLL.See related commentary by Janin and Esteller, p. 176.This article is highlighted in the In This Issue feature, p. 171

Table S1 shows CLL sample information; Table S2 shows protein expression detected in CLL and normal B cells using TMT proteomics; Table S3 shows top 150 transcripts with highest m6A density in B cells; Table S4 shows sequences of shRNAs, sgRNAs, and primers used in our study; Table S5 shows cellular pathways enriched in our study.

Numbers and ratios of dendritic cells and T cells migrated from skin explants

Sections show morphologic and immunohistochemical findings of MF lesion

Supplemental Figure 1 legend.

The contour plots shown provide representative gating strategies and histograms used for T cell and DC subsets and immune checkpoint expression

Supplemental Figure 2 legend.

Cutaneous T-cell lymphoma (CTCL) develops from clonally expanded CD4+ T cells in a background of chronic inflammation. Although dendritic cells (DCs) stimulate T cells and are present in skin, cutaneous T cells in CTCL do not respond with effective antitumor immunity. We evaluated primary T-cell and DC émigrés from epidermal and dermal explant cultures of skin biopsies from CTCL patients (n = 37) and healthy donors (n = 5). Compared with healthy skin, CD4+ CTCL populations contained more T cells expressing PD-1, CTLA-4, and LAG-3. CD8+ CTCL populations contained more T cells expressing CTLA-4 and LAG-3. CTCL populations also contained more T cells expressing the inducible T-cell costimulator (ICOS), a marker of T-cell activation. DC émigrés from healthy or CTCL skin biopsies expressed PD-L1, indicating that maturation during migration resulted in PD-L1 expression irrespective of disease. Most T cells did not express PD-L1. Using skin samples from 49 additional CTCL patients for an unsupervised analysis of genome-wide mRNA expression profiles corroborated that advanced T3/T4-stage samples expressed more checkpoint inhibition mRNA compared with T1/T2 stage patients or healthy controls. Exhaustion of activated T cells is therefore a hallmark of both CD4+ and CD8+ T cells isolated from the lesional skin of patients with CTCL, with increasing expression as the disease progresses. These results justify identification of antigens driving T-cell exhaustion and the evaluation of immune checkpoint inhibition to reverse T-cell exhaustion earlier in the treatment of CTCL. Cancer Immunol Res; 6(8); 900–9. ©2018 AACR.

PDF file - 167K, Different probes for the same gene vary within and across microarray platforms

Purpose:In classical Hodgkin lymphoma, the malignant Reed–Sternberg cells express the cell surface marker CD30. Brentuximab vedotin is an antibody–drug conjugate (ADC) that selectively delivers a potent cytotoxic agent, monomethyl auristatin E (MMAE), to CD30-positive cells. Although brentuximab vedotin elicits a high response rate (75%) in relapsed/refractory Hodgkin lymphoma, most patients who respond to brentuximab vedotin eventually develop resistance.Patients and Methods:We developed two brentuximab vedotin–resistant Hodgkin lymphoma cell line models using a pulsatile approach and observed that resistance to brentuximab vedotin is associated with an upregulation of multidrug resistance-1 (MDR1). We then conducted a phase I trial combining brentuximab vedotin and cyclosporine A (CsA) in patients with relapsed/refractory Hodgkin lymphoma.Results:Here, we show that competitive inhibition of MDR1 restored sensitivity to brentuximab vedotin in our brentuximab vedotin–resistant cell lines by increasing intracellular MMAE levels, and potentiated brentuximab vedotin activity in brentuximab vedotin–resistant Hodgkin lymphoma tumors in a human xenograft mouse model. In our phase I trial, the combination of brentuximab vedotin and CsA was tolerable and produced an overall and complete response rate of 75% and 42% in a population of patients who were nearly all refractory to brentuximab vedotin.Conclusions:This study may provide a new therapeutic strategy to combat brentuximab vedotin resistance in Hodgkin lymphoma. This is the first study reporting an effect of multidrug resistance modulation on the therapeutic activity of an ADC in humans. The expansion phase of the trial is ongoing and enrolling patients who are refractory to brentuximab vedotin to confirm clinical activity in this population with unmet need.

Purpose: Epithelial–mesenchymal transition (EMT) has been associated with metastatic spread and EGF receptor (EGFR) inhibitor resistance. We developed and validated a robust 76-gene EMT signature using gene expression profiles from four platforms using non–small cell lung carcinoma (NSCLC) cell lines and patients treated in the Biomarker-Integrated Approaches of Targeted Therapy for Lung Cancer Elimination (BATTLE) study.Experimental Design: We conducted an integrated gene expression, proteomic, and drug response analysis using cell lines and tumors from patients with NSCLC. A 76-gene EMT signature was developed and validated using gene expression profiles from four microarray platforms of NSCLC cell lines and patients treated in the BATTLE study, and potential therapeutic targets associated with EMT were identified.Results: Compared with epithelial cells, mesenchymal cells showed significantly greater resistance to EGFR and PI3K/Akt pathway inhibitors, independent of EGFR mutation status, but more sensitivity to certain chemotherapies. Mesenchymal cells also expressed increased levels of the receptor tyrosine kinase Axl and showed a trend toward greater sensitivity to the Axl inhibitor SGI-7079, whereas the combination of SGI-7079 with erlotinib reversed erlotinib resistance in mesenchymal lines expressing Axl and in a xenograft model of mesenchymal NSCLC. In patients with NSCLC, the EMT signature predicted 8-week disease control in patients receiving erlotinib but not other therapies.Conclusion: We have developed a robust EMT signature that predicts resistance to EGFR and PI3K/Akt inhibitors, highlights different patterns of drug responsiveness for epithelial and mesenchymal cells, and identifies Axl as a potential therapeutic target for overcoming EGFR inhibitor resistance associated with the mesenchymal phenotype. Clin Cancer Res; 19(1); 279–90. ©2012 AACR.

PDF file - 66K, CDH1 probes vary in their accuracy and dynamic range

Supplementary Figure 2

Supplementary Figure 1

PDF file - 50K, Mesenchymal lines are sensitive to Axl inhibition by SGI-7079

Purpose: Therapeutic strategies to enhance the efficacy of radioimmunotherapy have not been explored. Motexafin gadolinium is a novel anticancer agent that targets redox-dependent pathways and enhances sensitivity of tumor cells to ionizing radiation.Experimental Design: We did preclinical studies examining motexafin gadolinium combined with rituximab and/or radiation in lymphoma cells. We subsequently completed a phase I clinical trial combining escalating doses of motexafin gadolinium concurrently with standard [90Y]ibritumomab tiuxetan for patients with relapsed/refractory non-Hodgkin's lymphoma.Results: In HF1 lymphoma cells, motexafin gadolinium and rituximab resulted in synergistic cytotoxicity (combination index, 0.757) through a mitochondrial-mediated caspase-dependent pathway, whereas cell death in Ramos and SUDHL4 cells was additive. Motexafin gadolinium/rituximab combined with radiation (1-3 Gy) resulted in additive apoptosis. Twenty-eight of 30 patients were evaluable on the phase I clinical trial. Median age was 65 years (47-87 years), and histologies were marginal-zone (n = 1), mantle-cell (n = 3), diffuse large cell (n = 6), and follicular lymphoma (n = 18). Of all patients, 86% were rituximab refractory. Therapy was well tolerated, and no dose-limiting toxicity was seen. Overall response rate was 57% [complete remission (CR), 43%], with median time–to–treatment failure of 10 months (1-48+ months) and median duration-of-response of 17 months. Of note, all responses were documented at 4 weeks. Furthermore, in rituximab-refractory follicular lymphoma (n = 14), overall response rate was 86% (CR, 64%), with a median time–to–treatment failure of 14 months (2-48+ months).Conclusions: This represents the first report of a novel agent to be combined safely concurrently with radioimmunotherapy. Furthermore, tumor responses with [90Y]ibritumomab tiuxetan/motexafin gadolinium were prompt with a high rate of CRs, especially in rituximab-refractory follicular lymphoma. (Clin Cancer Res 2009;15(20):6462–71)

Supplementary Figure 1. Combination of ritonavir and metformin is growth inhibitory in solid tumors such as breast and ovarian cancers. Breast (A) ovarian (B) cancer cell lines were cultured in the presence of 20µM ritonavir, and/or increasing concentrations of metformin for 72 hours. Impact of treatments on cell proliferation was evaluated by an MTS assay. Doxorubicin (10uM) was used as a positive control.

PDF file - 175K

PDF file - 214K, The EMT signature genes

Supplementary Data from The Novel Expanded Porphyrin, Motexafin Gadolinium, Combined with [90Y]Ibritumomab Tiuxetan for Relapsed/Refractory Non-Hodgkin's Lymphoma: Preclinical Findings and Results of a Phase I Trial

Supplementary Table S1 from Glucocorticoid receptor transcriptional isoforms and resistance in multiple myeloma cells

PDF file - 71K, Percentage tumor volume compared to control, survival and therapeutic efficacy at days 17 and 38 post-treatment

Supplementary Figure legends

PDF file - 51K, EMT status of commonly mutated genes in NSCLC

Purpose: We have previously demonstrated that ritonavir targeting of glycolysis is growth inhibitory and cytotoxic in a subset of multiple myeloma cells. In this study, our objective was to investigate the metabolic basis of resistance to ritonavir and to determine the utility of cotreatment with the mitochondrial complex I inhibitor metformin to target compensatory metabolism.Experimental Design: We determined combination indices for ritonavir and metformin, impact on myeloma cell lines, patient samples, and myeloma xenograft growth. Additional evaluation in breast, melanoma, and ovarian cancer cell lines was also performed. Signaling connected to suppression of the prosurvival BCL-2 family member MCL-1 was evaluated in multiple myeloma cell lines and tumor lysates. Reliance on oxidative metabolism was determined by evaluation of oxygen consumption, and dependence on glutamine was assessed by estimation of viability upon metabolite withdrawal in the context of specific metabolic perturbations.Results: Ritonavir-treated multiple myeloma cells exhibited increased reliance on glutamine metabolism. Ritonavir sensitized multiple myeloma cells to metformin, effectively eliciting cytotoxicity both in vitro and in an in vivo xenograft model of multiple myeloma and in breast, ovarian, and melanoma cancer cell lines. Ritonavir and metformin effectively suppressed AKT and mTORC1 phosphorylation and prosurvival BCL-2 family member MCL-1 expression in multiple myeloma cell lines in vitro and in vivo.Conclusions: FDA-approved ritonavir and metformin effectively target multiple myeloma cell metabolism to elicit cytotoxicity in multiple myeloma. Our studies warrant further investigation into repurposing ritonavir and metformin to target the metabolic plasticity of myeloma to more broadly target myeloma heterogeneity and prevent the reemergence of chemoresistant aggressive multiple myeloma. Clin Cancer Res; 21(5); 1161–71. ©2014 AACR.

PDF file - 27K, SGI-7079 and erlotinib do not adversely affect animal body weight

PDF file - 96K, Structure of pyrrolopyrimidine AXL inhibitor SGI-7079

Supplementary Materials and Methods

Supplementary Table 1

The relationship between immune checkpoint status and disease outcome is a major focus of research in cutaneous T-cell lymphoma (CTCL), a disfiguring neoplastic dermatological disorder. Mycosis fungoides (MF) and Sézary syndrome (SS) are the two most common types of CTCL.The aim was to evaluate the immune checkpoint markers programmed death protein 1 (PD1), inducible T-cell co-stimulator (ICOS) and programmed death-ligand 1 (PD-L1) in skin biopsies from patients with CTCL relative to disease stage and overall survival.This consecutive case series enrolled 47 patients: 57% had stage IA-IIA disease and 43% had stage IIB-IVA2 disease (including seven with SS).PD1, PD-L1 and ICOS expression was seen in all biopsies. Notably, PD-L1 was predominantly expressed on histiocytes/macrophages, but focal expression on CTCL cells was seen. High expression of either ICOS or PD-L1 was associated with advanced-stage disease (P = 0·007 for both) and with the appearance of large-cell transformation (LCT), a histopathological feature associated with a poor prognosis (ICOS: P = 0·02; PD-L1: P = 0·002). PD1 expression was not significantly associated with disease stage (P = 0·12) or LCT (P = 0·49), but expression was high in SS biopsies. A high combined checkpoint marker score (PD1, PD-L1 and ICOS) was associated with advanced-stage disease (P = 0·001), LCT (P = 0·021) and lower overall survival (P = 0·014).These findings demonstrate the existence of a complex immunoregulatory microenvironment in CTCL and support the development of immunotherapies targeting ICOS and PD-L1 in advanced disease.

METTL16 has recently been identified as an RNA methyltransferase responsible for deposition of N(6)-methyladenosine (m(6)A) in a few transcripts. Whether METTL16 methylates a large set of transcripts, similar to METTL3 and METTL14, remains unclear. Here we show that METTL16 exerts both methyltransferase activity-dependent and -independent functions in gene regulation. In cell nucleus, METTL16 functions as an m(6)A writer to deposit m(6)A into hundreds of its specific mRNA targets. In cytosol, METTL16 promotes translation in an m(6)A-independent manner. More specifically, METTL16 directly interacts with eukaryotic initiation factor 3a/b (eIF3a/b) and ribosomal RNAs (rRNAs) through its Mtase domain, thereby facilitating the assembly of the translation initiation complex (TIC) and promoting translation of over 4,000 mRNA transcripts. Moreover, we demonstrate that METTL16 is critical for the tumorigenesis of hepatocellular carcinoma. Collectively, our studies reveal previously unappreciated dual functions of METTL16 as an m(6)A writer and a translation initiation facilitator, which together contribute to its essential function in tumorigenesis.

Richter’s transformation (RT) is a progression of chronic lymphocytic leukemia (CLL) to aggressive lymphoma.MGA(Max gene associated), a functional MYC suppressor, is mutated at 3% in CLL and 36% in RT. However, genetic models and molecular mechanisms ofMGAdeletion driving CLL to RT remain elusive. We established a novel RT mouse model by knockout ofMgain theSf3b1/MdrCLL model via CRISPR-Cas9 to determine the role ofMgain RT. Murine RT cells exhibit mitochondrial aberrations with elevated oxidative phosphorylation (OXPHOS). We identifiedNme1(Nucleoside diphosphate kinase) as aMgatarget through RNA sequencing and functional characterization, which drives RT by modulating OXPHOS. AsNME1is also a known MYC target without targetable compounds, we found that concurrent inhibition of MYC and ETC complex II significantly prolongs the survival of RT micein vivo. Our results suggest thatMga-Nme1axis drives murine CLL-to-RT transition via modulating OXPHOS, highlighting a novel therapeutic avenue for RT.Statement of SignificanceWe established a murine RT model through knockout ofMgain an existing CLL model based on co-expression ofSf3b1-K700E anddel(13q). We determined that theMGA/NME1regulatory axis is essential to the CLL-to-RT transition via modulation of mitochondrial OXPHOS, highlighting this pathway as a novel target for RT treatment.

Epigenetic dysregulation of cell cycle is a hallmark of tumorigenesis in multiple cancers, including hepatocellular carcinoma (HCC). Nonetheless, the epigenetic mechanisms underlying the aberrant cell cycle signaling and therapeutic response remain unclear. Here, we used an epigenetics-focused CRISPR interference screen and identified ACTR5 (actin-related protein 5), a component of the INO80 chromatin remodeling complex, to be essential for HCC tumor progression. Suppression of ACTR5 activated CDKN2A expression, ablated CDK/E2F-driven cell cycle signaling, and attenuated HCC tumor growth. Furthermore, high-density CRISPR gene tiling scans revealed a distinct HCC-specific usage of ACTR5 and its interacting partner IES6 compared to the other INO80 complex members, suggesting an INO80-independent mechanism of ACTR5/IES6 in supporting the HCC proliferation. Last, our study revealed the synergism between ACTR5/IES6-targeting and pharmacological inhibition of CDK in treating HCC. These results indicate that the dynamic interplay between epigenetic regulators, tumor suppressors, and cell cycle machinery could provide novel opportunities for combinational HCC therapy.

We describe here for the first time a lipid-binding-domain (LBD) in p38γ mitogen-activated protein kinase (MAPK) involved in the response of T cells to a newly identified inhibitor, CSH71. We describe how CSH71, which binds to both the LBD and the ATP-binding pocket of p38γ, is selectively cytotoxic to CTCL Hut78 cells but spares normal healthy peripheral blood mononuclear (PBMC) cells, and propose possible molecular mechanisms for its action. p38γ is a key player in CTCL development, and we expect that the ability to regulate its expression by specifically targeting the lipid-binding domain will have important clinical relevance. Our findings characterize novel mechanisms of gene regulation in T lymphoma cells and validate the use of computational screening techniques to identify inhibitors for therapeutic development.

BACKGROUND Literature regarding exosomes as mediators in intercellular communication to promote progression in mycosis fungoides (MF) is lacking. OBJECTIVES To characterize MF-derived exosomes and their involvement in the disease. METHODS Exosomes were isolated by ultracentrifugation from cutaneous T-cell lymphoma (CTCL) cell lines, and from plasma of patients with MF and controls (healthy individuals). Exosomes were confirmed by electron microscopy, NanoSight and CD81 staining. Cell-line exosomes were profiled for microRNA array. Exosomal microRNA (exomiRNA) expression and uptake, and plasma-cell-free microRNA (cfmiRNA) were analysed by reverse-transcriptase quantitative polymerase chain reaction. Exosome uptake was monitored by fluorescent labelling and CD81 immunostaining. Migration was analysed by transwell migration assay. RESULTS MyLa- and MJ-derived exosomes had a distinctive microRNA signature with abundant microRNA (miR)-155 and miR-1246. Both microRNAs were delivered into target cells, but only exomiR-155 was tested, demonstrating a migratory effect on target cells. Plasma levels of cfmiR-1246 were significantly highest in combined plaque/tumour MF, followed by patch MF, and were lowest in controls (plaque/tumour > patch > healthy), while cfmiR-155 was upregulated only in plaque/tumour MF vs. controls. Specifically, exomiR-1246 (and not exomiR-155) was higher in plasma of plaque/tumour MF than in healthy controls. Plasma exosomes from MF but not from controls increased cell migration. CONCLUSIONS Our findings show that MF-derived exosomes promote cell motility and are enriched with miR-155, a well-known microRNA in MF, and miR-1246, not previously reported in MF. Based on their plasma expression we suggest that they may serve as potential biomarkers for tumour burden.

Purpose of review In the article, we focus on the role of SUMOylation in tumorigenesis and cancer-related processes, including Epithelial-mesenchymal transition (EMT), metastasis, resistance to cancer therapies, and antitumor immunity. Clinical perspective on small ubiquitin-like modifier (SUMO) inhibitors will be discussed. Recent findings SUMOylation regulates multiple important biologic functions including gene transcription, DNA damage repair, cell cycle, and innate immunity. The SUMO pathway enzymes are usually elevated in various cancers and linked with cancer progression and poor clinical outcomes for patients. Recent studies have revealed the role of SUMOylation in EMT and metastasis through regulating E-Cadherin and Snail expression. Multiple studies demonstrate SUMOylation is involved with chemoresistance and hormone treatment resistance. Oncogene Myc and SUMOylation machinery regulation has been revealed in pancreatic cancer. SUMOylation is involved in regulating antitumor immune response through dendritic cells and T cells. A breakthrough has been made in targeting SUMOylation in cancer as first-in-class SUMO E1 inhibitor TAK-981 enters clinical trials. Summary SUMOylation plays an important role in tumor EMT, metastasis, therapy resistance, and antitumor immune response. Pharmaceutical inhibition of SUMOylation has become promising clinical therapy to improve the outcome of the existing chemo and immune therapies.

Poem by Steven T. Rosen

In patients with treatment-naive diffuse large B-cell lymphoma (DLBCL), the POLARIX study (A Study Comparing the Efficacy and Safety of Polatuzumab Vedotin With Rituximab-Cyclophosphamide, Doxorubicin, and Prednisone [R-CHP] Versus Rituximab-Cyclophosphamide, Doxorubicin, Vincristine, and Prednisone [R-CHOP] in Participants With Diffuse Large B-Cell Lymphoma) reported a 6.5% improvement in the 2-year progression-free survival (PFS), with no difference in overall survival (OS) or safety using polatuzumab vedotin, rituximab, cyclophosphamide, doxorubicin, and prednisone (pola-R-CHP) compared with standard rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP). We evaluated the cost-effectiveness of pola-R-CHP for DLBCL. We modeled a hypothetical cohort of US adults (mean age, 65 years) with treatment-naive DLBCL by developing a Markov model (lifetime horizon) to model the cost-effectiveness of pola-R-CHP and R-CHOP using a range of plausible long-term outcomes. Progression rates and OS were estimated from POLARIX. Outcome measures were reported in incremental cost-effectiveness ratios, with a willingness-to-pay (WTP) threshold of $150 000 per quality-adjusted life-year (QALY). Assuming a 5-year PFS of 69.6% with pola-R-CHP and 62.7% with R-CHOP, pola-R-CHP was cost-effective at a WTP of $150 000 (incremental cost-effectiveness ratio, $84 308/QALY). pola-R-CHP was no longer cost-effective if its 5-year PFS was 66.1% or lower. One-way sensitivity analysis revealed that pola-R-CHP is cost-effective up to a cost of $276 312 at a WTP of $150 000. pola-R-CHP was the cost-effective strategy in 56.6% of the 10 000 Monte Carlo iterations at a WTP of $150 000. If the absolute benefit in PFS is maintained over time, pola-R-CHP is cost-effective compared with R-CHOP at a WTP of $150 000/QALY. However, its cost-effectiveness is highly dependent on its long-term outcomes and costs of chimeric antigen receptor T-cell therapy. Routine usage of pola-R-CHP would add significantly to health care expenditures. Price reductions or identification of subgroups that have maximal benefit would improve cost-effectiveness.

Flavopiridol (FVP; Alvocidib), a CDKs inhibitor, is currently undergoing clinical trials for treatment of leukemia and other blood cancers. Our studies demonstrated that FVP also inhibited p38 kinases activities with IC50 (μM) for p38α: 1.34; p38 β: 1.82; p38γ: 0.65, and p38δ: 0.45. FVP showed potent cytotoxicity in cutaneous T-cell lymphoma (CTCL) Hut78 cells, with IC50

Because most patients with multiple myeloma (MM) develop resistance to current regimens, novel approaches are needed. Genetically modified, replication-competent oncolytic viruses exhibit high tropism for tumor cells regardless of cancer stage and prior treatment. Receptors of oncolytic herpes simplex virus 1 (oHSV-1), NECTIN-1, and HVEM are expressed on MM cells, prompting us to investigate the use of oHSV-1 against MM. Using oHSV-1-expressing GFP, we found a dose-dependent increase in the GFP+ signal in MM cell lines and primary MM cells. Whereas NECTIN-1 expression is variable among MM cells, we discovered that HVEM is ubiquitously and highly expressed on all samples tested. Expression of HVEM was consistently higher on CD138+/CD38+ plasma cells than in non-plasma cells. HVEM blocking demonstrated the requirement of this receptor for infection. However, we observed that, although oHSV-1 could efficiently infect and kill all MM cell lines tested, no viral replication occurred. Instead, we identified that oHSV-1 induced MM cell apoptosis via caspase-3 cleavage. We further noted that oHSV-1 yielded a significant decrease in tumor volume in two mouse xenograft models. Therefore, oHSV-1 warrants exploration as a novel potentially effective treatment option in MM, and HVEM should be investigated as a possible therapeutic target., Graphical Abstract, Receptors of oncolytic herpes simplex virus (oHSV-1), NECTIN-1, and HVEM are expressed on multiple myeloma (MM) cells. Whereas NECTIN-1 expression is variable among MM cells, HVEM is ubiquitously and highly expressed on all samples tested. However, no viral replication occurred. Instead, oHSV-1 induced MM cell apoptosis via caspase-3 cleavage.

BackgroundType I interferons (IFN-Is), secreted by hematopoietic cells, drive immune surveillance of solid tumors. However, the mechanisms of suppression of IFN-I-driven immune responses in hematopoietic malignancies including B-cell acute lymphoblastic leukemia (B-ALL) are unknown.MethodsUsing high-dimensional cytometry, we delineate the defects in IFN-I production and IFN-I-driven immune responses in high-grade primary human and mouse B-ALLs. We develop natural killer (NK) cells as therapies to counter the intrinsic suppression of IFN-I production in B-ALL.ResultsWe find that high expression of IFN-I signaling genes predicts favorable clinical outcome in patients with B-ALL, underscoring the importance of the IFN-I pathway in this malignancy. We show that human and mouse B-ALL microenvironments harbor an intrinsic defect in paracrine (plasmacytoid dendritic cell) and/or autocrine (B-cell) IFN-I production and IFN-I-driven immune responses. Reduced IFN-I production is sufficient for suppressing the immune system and promoting leukemia development in mice prone to MYC-driven B-ALL. Among anti-leukemia immune subsets, suppression of IFN-I production most markedly lowers the transcription of IL-15 and reduces NK-cell number and effector maturation in B-ALL microenvironments. Adoptive transfer of healthy NK cells significantly prolongs survival of overt ALL-bearing transgenic mice. Administration of IFN-Is to B-ALL-prone mice reduces leukemia progression and increases the frequencies of total NK and NK-cell effectors in circulation. Ex vivo treatment of malignant and non-malignant immune cells in primary mouse B-ALL microenvironments with IFN-Is fully restores proximal IFN-I signaling and partially restores IL-15 production. In B-ALL patients, the suppression of IL-15 is the most severe in difficult-to-treat subtypes with MYC overexpression. MYC overexpression promotes sensitivity of B-ALL to NK cell-mediated killing. To counter the suppressed IFN-I-induced IL-15 production in MYChighhuman B-ALL, we CRISPRa-engineered a novel human NK-cell line that secretes IL-15. CRISPRa IL-15-secreting human NK cells kill high-grade human B-ALL in vitro and block leukemia progression in vivo more effectively than NK cells that do not produce IL-15.ConclusionWe find that restoration of the intrinsically suppressed IFN-I production in B-ALL underlies the therapeutic efficacy of IL-15-producing NK cells and that such NK cells represent an attractive therapeutic solution for the problem of drugging MYC in high-grade B-ALL.