Pharmacological inhibition of JAK3 enhances the antitumor activity of imatinib in human chronic myeloid leukemia

Mechanisms of Resistance and Implications for Treatment Strategies in Chronic Myeloid Leukaemia

Simple Summary

Chronic myeloid leukaemia (CML) is a type of blood cancer that is currently well-managed with drugs that target cancer-causing proteins. However, a significant proportion of CML patients do not respond to those drug treatments or relapse when they stop those drugs because the cancer cells in those patients stop relying on that protein and instead develop a new way to survive. Therefore, new treatment strategies may be necessary for those patients. In this review, we discuss those additional survival pathways and outline combination treatment strategies to increase responses and clinical outcomes, improving the lives of CML patients.

Abstract

Tyrosine kinase inhibitors (TKIs) have revolutionised the management of chronic myeloid leukaemia (CML), with the disease now having a five-year survival rate over 80%. The primary focus in the treatment of CML has been on improving the specificity and potency of TKIs to inhibit the activation of the BCR::ABL1 kinase and/or overcoming resistance driven by mutations in the BCR::ABL1 oncogene. However, this approach may be limited in a significant proportion of patients who develop TKI resistance despite the effective inhibition of BCR::ABL1. These patients may require novel therapeutic strategies that target both BCR::ABL1-dependent and BCR::ABL1-independent mechanisms of resistance. The combination treatment strategies that target alternative survival signalling, which may contribute towards BCR::ABL1-independent resistance, could be a successful strategy for eradicating residual leukaemic cells and consequently increasing the response rate in CML patients.

Contribution of the bone marrow stromal cells in mediating drug resistance in hematopoietic tumors

The bone marrow microenvironment (BMM) provides input via production of cytokines, chemokines, extracellular matrixes in the context of lower oxygen levels that influences self-renewal, survival, differentiation, progression, and therapeutic resistance of multiple myeloma and leukemic cells. Within the context of the BMM, tumor cells are supported by osteoblasts, bone marrow stromal cells (BMSCs), fibroblasts, myeloid cells, endothelial cells and blood vessels, as well as extracellular matrix (ECM) that contribute to tumor progression. Environmental mediated-drug resistance (EM-DR) contains cell adhesion-mediated drug resistance (CAM-DR) and soluble factor-mediated drug resistance (SM-DR) that contributes to de novo drug resistance. In this review, we focus on the crosstalk between the BMM and tumor cells as well as mechanisms underlying the BMM contributing to drug resistance in hematologic malignancies.

Imatinib modulates pro-inflammatory microenvironment with angiostatic effects in experimental lung carcinogenesis

Lung cancer has second highest rate of incidence and mortality around the world. Smoking cigarettes is the main stream cause of lung carcinogenesis along with other factors such as spontaneous mutations, inactivation of tumor suppressor genes. The present study was aimed to identify the mechanistic role of Imatinib in the chemoprevention of experimental lung carcinogenesis in rat model. Gross morphological observations for tumor formation, histological examinations, RT-PCR, Western blotting, fluorescence spectroscopy and molecular docking studies were performed to elucidate the chemopreventive effects of Imatinib and support our hypothesis by various experiments. It is evident that immuno-compromised microenvironment inside solid tumors is responsible for tumor progression and drug resistance. Therefore, it is inevitable to modulate the pro-inflammatory signaling inside solid tumors to restrict neoangiogenesis. In the present study, we observed that Imatinib could downregulate the inflammatory signaling and also attributed angiostatic effects. Moreover, Imatinib also altered the biophysical properties of BAL cells such as plasma membrane potential, fluidity and microviscosity to restrict their infiltration and thereby accumulation to mount immuno-compromised environment inside the solid tumors during angiogenesis. Our molecular docking studies suggest that immunomodulatory and angiostatic properties of Imatinib could be either independent of each other or just a case of synergistic pleiotropy. Imatinib was observed to activate the intrinsic or mitochondrial pathway of apoptosis to achieve desired effects in cancer cell killings. Interestingly, binding of Imatinib inside the catalytic domain of PARP-1 also suggests that it has caspase-independent properties in promoting cancer cell deaths.

Hematological malignancies and molecular targeting therapy

Recent genetic analysis using next-generation sequencing (NGS) vastly improved the understanding of molecular mechanism of hematological malignancies. Many molecular targeting drugs have since been used in the clinic, which is timely as clinical outcomes using conventional chemotherapy and hematopoietic stem cell transplantation (HSCT) reached a plateau. The first memorable success in this field was imatinib, a first-generation tyrosine kinase inhibitor (TKI), which has been applied in chronic myeloid leukemia (CML) since 2001. Imatinib drastically changed CML treatment and many CML patients no longer require HSCT. Recently, the second generation TKIs, dasatinib, nilotinib, and ponatinib, have also been available for CML patients. Acute lymphoblastic leukemia (ALL) is sub-categorized based on cytogenetic or molecular genetic abnormalities. Chemotherapy and HSCT combined with TKI improved the event-free survival rate from 20% to 80% in Philadelphia (Ph) chromosome-positive ALL. Reportedly, another Ph-like ALL subgroup with poor prognosis can also be treated by TKIs; additionally, cell therapies that include bispecific T-cell engagers or chimeric antigen receptor (CAR)-T therapy are emerging. Acute myeloid leukemia (AML) is a heterogenous disease and FMS-like related tyrosine kinase-3 (FLT3)-internal tandem duplication, is the most robust marker for poor prognosis. Several first-generation TKIs have been studied for clinical use. Notably, chemotherapy plus midostaurin improved survival compared with chemotherapy alone. Therefore, midostaurin was approved to treat adult AML patients with FLT3-ITD in 2017. Gemtuzumab ozogamicin, a selective anti-CD33 antibody-calicheamicin conjugate, is approved for clinical practice. Many molecular targeting agents are now being used for hematological malignancies.

Chronic Myeloid Leukemia in a Patient Receiving Tofacitinib: A Case Report and Literature Review

Background

Tofacitinib is a new oral Janus kinase inhibitor that has shown promising clinical benefit in various rheumatologic diseases. However, many concerns related to the development of malignancies have been reported with its use.

Case Presentation

A 43-year-old female patient received tofacitinib for refractory rheumatoid arthritis (RA). Two years after 5 mg bid daily dosing, the patient developed chronic myelogenous leukemia (CML), for which she received imatinib and tofacitinib was discontinued. She then remained in remission for rheumatoid arthritis and within the expected milestone outcome for her CML.

Conclusion

This is the first reported case of CML after the use of tofacitinib. This event is of particular interest knowing the possible benefits tofacitinib carries in the treatment of CML demonstrated in a few studies.

Deciphering the mechanism of Indirubin and its derivatives in the inhibition of Imatinib resistance using a "drug target prediction-gene microarray analysis-protein network construction" strategy

Background

The introduction of imatinib revolutionized the treatment of chronic myeloid leukaemia (CML), substantially extending patient survival. However, imatinib resistance is currently a clinical problem for CML. It is very importantto find a strategy to inhibit imatinib resistance.

Methods

(1) We Identified indirubin and its derivatives and predicted its putative targets; (2) We downloaded data of the gene chip GSE2810 from the Gene Expression Omnibus (GEO) database and performed GEO2R analysis to obtain differentially expressed genes (DEGs); and (3) we constructed a P-P network of putative targets and DEGs to explore the mechanisms of action and to verify the results of molecular docking.

Result

We Identified a total of 42 small-molecule compounds, of which 15 affected 11 putative targets, indicating the potential to inhibit imatinib resistance; the results of molecular docking verified these results. Six biomarkers of imatinib resistance were characterised by analysing DEGs.

Conclusion

The 15 small molecule compounds inhibited imatinib resistance through the cytokine-cytokine receptor signalling pathway, the JAK-stat pathway, and the NF-KB signalling pathway. Indirubin and its derivatives may be new drugsthat can combat imatinib resistance.

Electronic supplementary material

The online version of this article (10.1186/s12906-019-2471-2) contains supplementary material, which is available to authorized users.