Immunotherapy-resistant acute lymphoblastic leukemia cells exhibit reduced CD19 and CD22 expression and BTK pathway dependency.

While therapies targeting CD19 by antibodies, chimeric antigen receptor T cells (CAR-T), and T cell engagers have improved the response rates in B cell malignancies, the emergence of resistant cell populations with low CD19 expression can lead to relapsed disease. We developed an in vitro model of adaptive resistance facilitated by chronic exposure of leukemia cells to a CD19 immunotoxin. Single-cell RNA-Seq (scRNA-Seq) showed an increase in transcriptionally distinct CD19lo populations among resistant cells.

Combined epigenetic and immunotherapy for blastic and classical mantle cell lymphoma.

Classical MCL (cMCL) constitutes 6-8% of all B cell NHL. Despite recent advances, MCL is incurable except with allogeneic stem cell transplant. Blastic mantle cell lymphoma (bMCL) is a rarer subtype of cMCL associated with an aggressive clinical course and poor treatment response, frequent relapse and poor outcomes.

SOX11 Inhibitors Are Cytotoxic in Mantle Cell Lymphoma.

Purpose: Mantle cell lymphoma (MCL) is a fatal subtype of non-Hodgkin lymphoma. SOX11 transcription factor is overexpressed in the majority of nodal MCL. We have previously reported that B cell-specific overexpression of SOX11 promotes MCL pathogenesis via critically increasing BCR signaling .

A phase II study of pomalidomide, daily oral cyclophosphamide, and dexamethasone in relapsed/refractory multiple myeloma.

Relapsed/refractory multiple myeloma patients treated with pomalidomide and dexamethasone have an overall response rate (ORR) of ∼30% and median progression-free survival (PFS) of 4-5 months. Previous studies explored addition of weekly cyclophosphamide, but we hypothesized that daily dosing allows for better synergy. We report the open-label, single-center phase II study of pomalidomide, daily cyclophosphamide and weekly dexamethasone (PCD).

Mutation-derived Neoantigen-specific T-cell Responses in Multiple Myeloma.

Purpose: Somatic mutations in cancer cells can give rise to novel protein sequences that can be presented by antigen-presenting cells as neoantigens to the host immune system. Tumor neoantigens represent excellent targets for immunotherapy, due to their specific expression in cancer tissue. Despite the widespread use of immunomodulatory drugs and immunotherapies that recharge T and NK cells, there has been no direct evidence that neoantigen-specific T-cell responses are elicited in multiple myeloma.

SOX11 augments BCR signaling to drive MCL-like tumor development.

Mantle cell lymphoma (MCL) is characterized by increased B-cell receptor (BCR) signaling, and BTK inhibition is an effective therapeutic intervention in MCL patients. The mechanisms leading to increased BCR signaling in MCL are poorly understood, as mutations in upstream regulators of BCR signaling such as CD79A, commonly observed in other lymphomas, are rare in MCL. The transcription factor SOX11 is overexpressed in the majority (78% to 93%) of MCL patients and is considered an MCL-specific oncogene.

Dual Targeting of CDK4 and ARK5 Using a Novel Kinase Inhibitor ON123300 Exerts Potent Anticancer Activity against Multiple Myeloma.

Multiple myeloma is a fatal plasma cell neoplasm accounting for over 10,000 deaths in the United States each year. Despite new therapies, multiple myeloma remains incurable, and patients ultimately develop drug resistance and succumb to the disease. The response to selective CDK4/6 inhibitors has been modest in multiple myeloma, potentially because of incomplete targeting of other critical myeloma oncogenic kinases.

Epigenetic therapy overcomes treatment resistance in T cell prolymphocytic leukemia.

T cell prolymphocytic leukemia (T-PLL) is a rare, mature T cell neoplasm with distinct features and an aggressive clinical course. Early relapse and short overall survival are commonplace. Use of the monoclonal anti-CD52 antibody alemtuzumab has improved the rate of complete remission and duration of response to more than 50% and between 6 and 12 months, respectively.

Harnessing Noxa demethylation to overcome Bortezomib resistance in mantle cell lymphoma.

Bortezomib (BZM) is the first proteasome inhibitor approved for relapsed Mantle Cell Lymphoma (MCL) with durable responses seen in 30%-50% of patients. Given that a large proportion of patients will not respond, BZM resistance is a significant barrier to use this agent in MCL. We hypothesized that a subset of aberrantly methylated genes may be modulating BZM response in MCL patients.

Integrative genomic analysis of temozolomide resistance in diffuse large B-cell lymphoma.

Purpose: Despite advances, there is an urgent need for effective therapeutics for relapsed diffuse large B-cell lymphoma, particularly in elderly patients and primary central nervous system (CNS) lymphoma. Temozolomide (TMZ), an oral DNA-alkylating agent routinely used in the therapy of glioblastoma multiforme, is active in patients with primary CNS lymphoma but the response rates are low. The mechanisms contributing to TMZ resistance are unknown.

HDAC inhibitors and decitabine are highly synergistic and associated with unique gene-expression and epigenetic profiles in models of DLBCL.

Interactions between histone deacetylase inhibitors (HDACIs) and decitabine were investigated in models of diffuse large B-cell lymphoma (DLBCL). A number of cell lines representing both germinal center B-like and activated B-cell like DLBCL, patient-derived tumor cells and a murine xenograft model were used to study the effects of HDACIs and decitabine in this system. All explored HDACIs in combination with decitabine produced a synergistic effect in growth inhibition and induction of apoptosis in DLBCL cells.

Genomewide DNA methylation analysis reveals novel targets for drug development in mantle cell lymphoma.

Mantle cell lymphoma (MCL) is a mostly incurable malignancy arising from naive B cells (NBCs) in the mantle zone of lymph nodes. We analyzed genomewide methylation in MCL patients with the HELP (HpaII tiny fragment Enrichment by Ligation-mediated PCR) assay and found significant aberrancy in promoter methylation patterns compared with normal NBCs. Using biologic and statistical criteria, we further identified 4 hypermethylated genes CDKN2B, MLF-1, PCDH8, and HOXD8 and 4 hypomethylated genes CD37, HDAC1, NOTCH1, and CDK5 when aberrant methylation was associated with inverse changes in mRNA levels.

Small heat shock protein hsp27 as a possible mediator of intercellular adhesion-induced drug resistance in human larynx carcinoma HEp-2 cells.

The confluence-dependent resistance of human larynx carcinoma HEp-2 cells to hydrogen peroxide and a new antitumor drug based on the combination of vitamins C and B12b was studied. It was found that this resistance in growing cells is suppressed by the disruption of intercellular contacts by EGTA and is related neither to the activity of P-glycoprotein nor to the content of intracellular glutathione and the activities of glutathione S-transferases, glutathione peroxidase and glutathionine reductase. Here we showed that the level of expression of the small heat shock protein hsp27, which is known to protect cells from a variety of stresses associated with apoptosis, in growing confluent cells both in the presence and absence of the vitamins B12b and C is much higher (about 20-25 times) than in non-confluent cells.