abt-199 and Leukemia

Topics: Azacitidine; Fanconi Anemia; Humans; Leukemia; Nuclear Proteins

Topics: Acute Disease; Adolescent; Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Bridged Bicyclo Compounds, Heterocyclic; Cytarabine; Female; Granulocyte Colony-Stimulating Factor; Humans; Leukemia; Male; Middle Aged; Recurrence; Salvage Therapy; Sulfonamides; Vidarabine

Topics: Antineoplastic Combined Chemotherapy Protocols; Azacitidine; Bridged Bicyclo Compounds, Heterocyclic; Child; Humans; Leukemia; Leukemia, Myeloid, Acute; Sulfonamides

Topics: Antineoplastic Combined Chemotherapy Protocols; Azacitidine; Bridged Bicyclo Compounds, Heterocyclic; Humans; Leukemia; Leukemia, Myeloid, Acute; Phenotype; Sulfonamides

Human leukemia U937 cells that were continuously treated with hydroquinone (HQ) were transformed into U937/HQ cells with increased MCL1 and BCL2L1 expression. Compared with their parental cells, U937/HQ cells were less sensitive to ABT-263 (BCL2/BCL2L1 inhibitor)/ABT-199 (BCL2 inhibitor) cytotoxicity. The combination of WEHI-539 (BCL2L1 inhibitor) with either ABT-199 or ABT-263 showed synergistic cytotoxicity to U937 and U937/HQ cells. Therefore, we further investigated the cytotoxic mechanism induced by the combination of WEHI-539 and ABT-199. The combined treatment of WEHI-539 and ABT-199 induced NOX4/ROS/p38 MAPK axis-mediated autophagy, which in turn accelerated β-TrCP mRNA turnover. Downregulation of β-TrCP increased Sp1 expression, thereby promoting Sp1-mediated NOXA transcription, which in turn induced NOXA-dependent MCL1 degradation. Enforced expression of MCL1 alleviated the cytotoxicity of WEHI-539 plus ABT-199 to induce the loss of mitochondrial membrane potential and cell viability. WEHI-539 alone induced Sp1/NOXA axis-mediated MCL1 downregulation, while ABT-199 significantly decreased the dose of WEHI-539 by approximately 350- and 50-fold to induce MCL1 suppression in parental and HQ-selected cells, respectively. Furthermore, WEHI-539 sensitized ABT-199-resistant U937 cells to ABT-199 cytotoxicity by inducing NOXA-mediated degradation of MCL1. Collectively, the data in this study indicate that ABT-199 and WEHI-539 cooperatively induce NOXA-dependent MCL1 degradation, and the inhibition of MCL1 mainly explains their combined cytotoxicity in parental, HQ-selected, and ABT-199-resistant U937 cells.

Topics: Antineoplastic Agents; Apoptosis; bcl-X Protein; beta-Transducin Repeat-Containing Proteins; Bridged Bicyclo Compounds, Heterocyclic; Cell Line, Tumor; Humans; Leukemia; Myeloid Cell Leukemia Sequence 1 Protein; Proto-Oncogene Proteins c-bcl-2; Sulfonamides

Chimeric antigen receptor (CAR) T cell therapy has shown promising responses in patients with refractory or relapsed aggressive B-cell malignancies that are resistant to conventional chemotherapy or stem cell transplantation. A potentially combinatorial therapeutic strategy may be the inhibition of anti-apoptotic Bcl-2 family proteins, overexpressed in most cancer cells. In this study we investigated the combination of 3rd-generation CD19.CAR-T cells and the BH3 mimetics venetoclax, a Bcl-2 inhibitor, or S63845, a Mcl-1 inhibitor, under three different treatment conditions: pre-sensitization of cancer cells with BH3 mimetics followed by CAR-T cell treatment, simultaneous combination therapy, and the administration of BH3 mimetics after CAR-T cell treatment. Our results showed that administration of CAR-T cells and BH3 mimetics had a significant effect on the quantity and quality of CD19.CAR-T cells. The administration of BH3 mimetics prior to CAR-T cell therapy exerted an enhanced cytotoxic efficacy by upregulating the CD19 expression and pro-apoptotic proteins in highly sensitive tumor cells, and thereby improving both CD19.CAR-T cell cytotoxicity and persistence. In simultaneous and post-treatment approaches, however, the quantity of CAR-T cells was adversely affected. Our findings indicate pre-sensitization of highly sensitive tumor cells with BH3 mimetics could enhance the cytotoxic efficacy of CAR-T cell treatment.

Topics: Antineoplastic Agents; Apoptosis; Apoptosis Regulatory Proteins; B-Lymphocytes; Bridged Bicyclo Compounds, Heterocyclic; Cell Survival; Coculture Techniques; Combined Modality Therapy; Gene Expression Regulation, Leukemic; Humans; Immunotherapy, Adoptive; K562 Cells; Leukemia; Lymphoma; Receptors, Chimeric Antigen; Sulfonamides; T-Lymphocytes

The BH3-only apoptosis agonists BAD and NOXA target BCL-2 and MCL-1 respectively and co-operate to induce apoptosis. On this basis, therapeutic drugs targeting BCL-2 and MCL-1 might have enhanced activity if used in combination. We identified anti-leukaemic drugs sensitising to BCL-2 antagonism and drugs sensitising to MCL-1 antagonism using the technique of dynamic BH3 profiling, whereby cells were primed with drugs to discover whether this would elicit mitochondrial outer membrane permeabilisation in response to BCL-2-targeting BAD-BH3 peptide or MCL-1-targeting MS1-BH3 peptide. We found that a broad range of anti-leukaemic agents-notably MCL-1 inhibitors, DNA damaging agents and FLT3 inhibitors-sensitise leukaemia cells to BAD-BH3. We further analysed the BCL-2 inhibitors ABT-199 and JQ1, the MCL-1 inhibitors pladienolide B and torin1, the FLT3 inhibitor AC220 and the DNA double-strand break inducer etoposide to correlate priming responses with co-operative induction of apoptosis. ABT-199 in combination with pladienolide B, torin1, etoposide or AC220 strongly induced apoptosis within 4 hours, but the MCL-1 inhibitors did not co-operate with etoposide or AC220. In keeping with the long half-life of BCL-2, the BET domain inhibitor JQ1 was found to downregulate BCL-2 and to prime cells to respond to MS1-BH3 at 48, but not at 4 hours: prolonged priming with JQ1 was then shown to induce rapid cytochrome C release when pladienolide B, torin1, etoposide or AC220 were added. In conclusion, dynamic BH3 profiling is a useful mechanism-based tool for understanding and predicting co-operative lethality between drugs sensitising to BCL-2 antagonism and drugs sensitising to MCL-1 antagonism. A plethora of agents sensitised cells to BAD-BH3-mediated mitochondrial outer membrane permeabilisation in the dynamic BH3 profiling assay and this was associated with effective co-operation with the BCL-2 inhibitory compounds ABT-199 or JQ1.

Topics: Antineoplastic Agents; Apoptosis; Azepines; Bridged Bicyclo Compounds, Heterocyclic; Cell Line, Tumor; Drug Combinations; Humans; Indoles; Leukemia; Myeloid Cell Leukemia Sequence 1 Protein; Proto-Oncogene Proteins c-bcl-2; Sulfonamides; Triazoles

Venetoclax (ABT-199), a first-in-class orally bioavailable BCL-2-selective inhibitor, was recently approved by the FDA for use in patients with 17p-deleted chronic lymphocytic leukemia who have received prior therapy. It is also being evaluated in numerous clinical trials for treating patients with various hematologic malignancies. As with any targeted cancer therapy, it is critically important to identify potential mechanisms of resistance, both for patient stratification and developing strategies to overcome resistance, either before it develops or as it emerges.. In order to gain a more comprehensive insight into the nature of venetoclax resistance mechanisms, we evaluated the changes in the BCL-2 family members at the genetic and expression levels in seven different venetoclax-resistant derived leukemia and lymphoma cell lines.. Gene and protein expression analyses identified a number of different alterations in the expression of pro- and anti-apoptotic BCL-2 family members. In the resistant derived cells, an increase in either or both the anti-apoptotic proteins BCL-X. Overall our study identified numerous changes in multiple resistant lines; the changes were neither mutually exclusive nor universal across the cell lines tested, thus exemplifying the complexity and heterogeneity of potential resistance mechanisms. Identifying and evaluating their contribution has important implications for both patient selection and the rational development of strategies to overcome resistance.

Topics: Apoptosis; bcl-X Protein; Bridged Bicyclo Compounds, Heterocyclic; Cell Line, Tumor; Cell Lineage; Drug Resistance, Neoplasm; Gene Expression Regulation, Neoplastic; Humans; Leukemia; Lymphoma; Myeloid Cell Leukemia Sequence 1 Protein; Proto-Oncogene Proteins c-bcl-2; Sulfonamides