Abrogation of histone deacetylases (HDACs) decreases survival of chronic myeloid leukemia cells: New insight into attenuating effects of the PI3K/c-Myc axis on panobinostat cytotoxicity

SOHO State of the Art Updates and Next Questions: Combination Therapy in Chronic Myeloid Leukemia in Chronic Phase

Therapeutic strategies for chronic myeloid leukemia (CML) are rapidly evolving, with novel agents emerging to address the limitations of current treatments. Goals of CML management are disease control and achieve a deep and sustained molecular response for a possible successful treatment-free remission (TFR). However, a significant proportion of patients fail to reach adequate molecular response and require sequential therapies. A crucial aspect of treatment resistance lies in the persistence of leukemic stem cells (LSCs), which serve as a reservoir for disease recurrence. Increasing focus is placed on combination strategies to overcome the constraints of TKI monotherapy. Various strategies have been explored, starting with the combination of interferon (IFN) and TKIs. The investigation of alternative administration methods, dosing regimens, or extended treatment durations in clinical trials involving IFN represents potential avenues to address current conflicting results. Additionally, the combination of ATP-competitive TKIs with asciminib has shown encouraging preclinical and clinical results, with further data needed for a comprehensive safety profile. Recently, efforts to inhibit other signaling pathways have been explored but with contrasting results. Despite ongoing advancements, TKIs remain the cornerstone of both current and future combination therapies. Their integration with personalized approaches is crucial to overcome complex biological challenges and ensure long-term, effective and safe treatment for CML patients.

Insights into existing and futuristic treatment approach for chronic myeloid leukaemia

Oncogenes play a crucial part in human cancer development, and when particular drugs obstruct the proteins produced by these oncogenes, the tumoural process can be ceased. For instance, in chronic myeloid leukaemia (CML), all pathological traits are associated with a single oncogene, BCR-ABL1. CML is a triphasic cancerous disorder of haematopoietic stem cells, marked by a balanced translocation between chromosomes 9 and 22, leading to the genesis of a Philadelphia chromosome encompassing the BCR-ABL1 fusion gene. This fusion oncogene further produces a constitutive active tyrosine kinase protein, enhancing the downstream signalling pathways and constitutes cancer. The treatment for CML has been entirely altered from chemotherapy and immunotherapy to targeted therapy with the emergence of tyrosine kinase inhibitors (TKIs) which inhibit BCR-ABL1 kinase activity. However, the inhibitory mechanism of TKIs is constrained by BCR-ABL1 dependent and independent resistance mechanisms, prompting the exploration of novel therapeutics through extensive clinical trials to develop next-generation drugs with enhanced potency. The persistent challenges posed by CML have motivated researchers to seek innovative strategies for its eradication, such as the application of the genome editing tool CRISPR/Cas9. This review provides insights into existing CML diagnoses, treatment modalities, resistance mechanisms, drugs under trial phases and new potential therapeutic drugs. Furthermore, the review looks ahead to a visionary perspective wherein the CRISPR/Cas9 approach holds the potential to evolve into a prospective curative measure for CML.

Pharmacotherapeutic advances for chronic myelogenous leukemia: beyond tyrosine kinase inhibitors

INTRODUCTION

Despite the notable success of tyrosine kinase inhibitors (TKIs) in treating chronic myeloid leukemia (CML), a subset of patients experiences resistance, or relapse after discontinuation. This challenge is attributed to the Ph+ leukemia stem cells (LSCs) pool not fully involved in the inhibition process due to the current therapeutic approach.

AREAS COVERED

Current pharmacological advancements in CML therapy focus on targeting LSCs, intervening in self-renewal pathways, and exploiting biological vulnerabilities. Beyond BCR::ABL1 inhibition, innovative approaches include immunotherapy, epigenetic modulation, and interference with microenvironmental mechanisms.

EXPERT OPINION

Diverse therapeutic strategies beyond TKIs are under investigation. Immunotherapy with interferon-α (IFN-α) shows some biological effects, although further research is needed for optimal application in enhancing discontinuation rates. Other compounds were able to mobilize Ph+ LSCs from the bone marrow niche (DPP-IV inhibitor vildagliptin or PAI-1 inhibitor TM5614) increasing the LSC clearance or target the CD26, a Ph+ specific surface receptor. It is noteworthy that the majority of these alternative strategies still incorporate TKIs. In conclusion, novel therapeutic perspectives are emerging for CML, holding the potential for substantial advancements in disease treatment.

C-Myc inhibition intensified the anti-leukemic properties of Imatinib in chronic myeloid leukemia cells

BACKGROUND

Due to its remarkable efficacy in producing hematologic, cytogenetic, and molecular remissions, the FDA approved Imatinib as the first-line treatment for newly diagnosed Chronic Myeloid Leukemia (CML) patients. However, in some patients, failure to completely eradicate leukemic cells and the escape of these cells from death will lead to the development of resistance to Imatinib, and many are concerned about the prospects of this Tyrosine Kinase Inhibitor (TKI). It has been documented that the compensatory overexpression of c-Myc is among the most critical mechanisms that promote drug efflux and resistance in CML stem cells.

METHODS

In order to examine the potential of c-Myc inhibition through the use of 10058-F4 to enhance the anti-leukemic properties of Imatinib, we conducted trypan blue and MTT assays. Additionally, we employed flow cytometric analysis and qRT-PCR to assess the effects of this combination on cell cycle progression and apoptosis.

RESULTS

The findings of our study indicate that the combination of 10058-F4 and Imatinib exhibited significantly stronger anti-survival and anti-proliferative effects on CML-derived-K562 cells in comparison to either agent administered alone. It is noteworthy that these results were also validated in the CML-derived NALM-1 cell line. Molecular analysis of this synergistic effect revealed that the inhibition of c-Myc augmented the efficacy of Imatinib by modulating the expression of genes related to cell cycle, apoptosis, autophagy, and proteasome.

CONCLUSIONS

Taken together, the findings of this investigation have demonstrated that the suppression of the c-Myc oncoprotein through the use of 10058-F4 has augmented the effectiveness of Imatinib, suggesting that this amalgamation could offer a fresh perspective on an adjunctive treatment for individuals with CML. Nevertheless, additional scrutiny, encompassing in-vivo examinations and clinical trials, is requisite.

A Review on the Therapeutic Role of TKIs in Case of CML in Combination With Epigenetic Drugs

Chronic myeloid leukemia is a malignancy of bone marrow that affects white blood cells. There is strong evidence that disease progression, treatment responses, and overall clinical outcomes of CML patients are influenced by the accumulation of other genetic and epigenetic abnormalities, rather than only the BCR/ABL1 oncoprotein. Both genetic and epigenetic factors influence the efficacy of CML treatment strategies. Targeted medicines known as tyrosine-kinase inhibitors have dramatically improved long-term survival rates in CML patients during the previous 2 decades. When compared to earlier chemotherapy treatments, these drugs have revolutionized CML treatment and allowed most people to live longer lives. Although epigenetic inhibitors' activity is disrupted in many cancers, including CML, but when combined with TKI, they may offer potential therapeutic strategies for the treatment of CML cells. The epigenetics of tyrosine kinase inhibitors and resistance to them is being studied, with a particular focus on imatinib, which is used to treat CML. In addition, the use of epigenetic drugs in conjunction with TKIs has been discussed. Resistance to TKIs is still a problem in curing the disease, necessitating the development of new therapies. This study focused on epigenetic pathways involved in CML pathogenesis and tumor cell resistance to TKIs, both of which contribute to leukemic clone breakout and proliferation.

MYC: a multipurpose oncogene with prognostic and therapeutic implications in blood malignancies

MYC oncogene is a transcription factor with a wide array of functions affecting cellular activities such as cell cycle, apoptosis, DNA damage response, and hematopoiesis. Due to the multi-functionality of MYC, its expression is regulated at multiple levels. Deregulation of this oncogene can give rise to a variety of cancers. In this review, MYC regulation and the mechanisms by which MYC adjusts cellular functions and its implication in hematologic malignancies are summarized. Further, we also discuss potential inhibitors of MYC that could be beneficial for treating hematologic malignancies.