Developing therapeutic approaches for chronic myeloid leukemia: a review.

Modern clinical therapy of chronic myeloid leukemia (CML) with TKIs is highly efficacious in most CML patients, while it is not remedial and generally confined due to intolerance or resistance. CML is currently considered a severe disease. Interestingly, stem cell transplantation in the past decade was an attractive clinical therapeutic option in CML patients, but it is not successful due to independently more death rates in older patients. So, the targeting of BCR::ABL oncoprotein is extensively used to enhance the reduction in a higher percentage of CML patients by tyrosine kinase inhibitors (TKIs). However, resistance or intolerance responses to these inhibitors are responsible for future deterioration and further development of disease. At this point, the clinical treatment of CML is a major challenge, and the lack of molecular responses to TKIs are not succeeded with chemotherapy alone. So, the considerable efficacious clinical necessities remain unmet. Therefore, continuous efforts are needed to explore new potential treatment strategies with an increasing understanding of CML biology. Therefore, this review deals with the investigation of TKI treatment with interferon, chemotherapy (Hydroxyurea, Homoharringtonine, Omacetaxine, Cytarabine), and several other new TKIs under beneficial clinical trials. Additionally, the approaches towards TKIs-resistant or intolerant CML cells where the respective signaling pathway gets up-regulated are also targeted with its inhibitor. This review presents evidence that new TKIs under clinical and pre-clinical trials may improve the chemotherapy of CML.

Alterations in cellular metabolisms after Imatinib therapy: a review.

Chronic myeloid leukemia (CML) is characterized by the possession of the Philadelphia chromosome, which contains the Bcr-Abl oncogene that codes for the oncoprotein BCR-ABL. Through glucose metabolism, glycolysis, and the translocation of the high-affinity glucose transporter to the cell surface, BCR-ABL modulates various signaling pathways in CML cells and maintains ATP turnover in tumor cells. Given the effective results of anti-tumor drugs in normalizing abnormal cellular metabolism, Imatinib (IM) has begun to be investigated and proven to be a highly potent tyrosine kinase inhibitor (TKI) in CML therapy. Initially, IM was tested for aberrant glucose metabolism, but all four metabolisms (glucose, lipid, amino acid, and nucleotide) are interrelated and enhance tumor growth under stress; eventually, the other three metabolisms were investigated. Subsequent effects of IM therapy showed a switch from glycolysis to the tricarboxylic acid cycle, upregulation of pentose phosphate pathway-associated oxidative pathways, and internal translocation of glucose transporters. In terms of lipid metabolism, IM had contradictory results: in one study, it served as a triglyceride and total cholesterol regulator, while in another study, it had no impact. The effect of IM on altered amino acid and nucleotide metabolisms was investigated using a multi-omics approach, which revealed a decrease in sulfur-containing amino acids, aromatic amino acids, and nucleotide biosynthesis. So, despite the mixed effect on cellular metabolism, IM has more positive effects, and therefore, the drug proved to be better than other TKIs. The present study is one approach to determine the transformative activities of IM against CML-associated metabolic changes, but further investigation is still needed to uncover more potentials of IM.

Transport and metabolism of tyrosine kinase inhibitors associated with chronic myeloid leukemia therapy: a review.

Imatinib, nilotinib, dasatinib, bosutinib, ponatinib, and asciminib are FDA-approved tyrosine kinase inhibitors (TKIs) for chronic myeloid leukemia (CML), each of which has a specific pharmacological profile. Asciminib has been recently (2021) approved for patients resistant to former TKIs, and because the binding site of this drug (the myristoyl pocket in the ABL1 kinase) is different from that of other TKIs (ATP-binding sites), it is, therefore, effective against T315I mutation of BCR-ABL oncoprotein. All TKIs have a different pharmacological profile due to different chemical structures. Imatinib is the only TKI whose absorption depends on both influx (OCT1 and OATP1A2) and efflux (ABCB1 and ABCG2) transporters, whereas the others rely only on efflux transporters. The efflux of dasatinib is also regulated by ABCC4 and ABCC6 transporters. Nilotinib and ponatinib are transported passively, as no role of transporters has been found in their case. A phenomenon common to all in the metabolic aspect is that the CYP3A4 isoform of CYP450 primarily metabolizes TKIs. Not only does CYP3A4, flavin-containing monooxygenase 3 (FMO3), and uridine 5'-diphospho-glucuronosyltransferase (UGT) also metabolize dasatinib, and similarly, by glucuronidation process, asciminib gets metabolized by UGT enzymes (UGT1A3, UGT1A4, UGT2B7, and UGT2B17). Additionally, the side effects of TKIs are categorized as hematological (thrombocytopenia, neutropenia, anemia, and cardiac dysfunction) and non-hematological (diarrhea, nausea, vomiting, pleural effusion, and skin rash). However, few toxicities are drug-specific, like degradation of biomolecules by ponatinib-glutathione (P-GSH) conjugates and clinical pancreatitis (dose-limited toxicity and manageable by dosage alterations) are related to ponatinib and asciminib, respectively. This review focuses on the pharmacokinetics of approved TKIs related to CML therapy to comprehend their specificity, tolerability, and off-target effects, which could help clinicians to make a patient-specific selection of CML drugs by considering concomitant diseases and risk factors to the patients.

Combating TKI resistance in CML by inhibiting the PI3K/Akt/mTOR pathway in combination with TKIs: a review.

Chronic myeloid leukemia (CML), a myeloproliferative hematopoietic cancer, is caused by a genetic translocation between chromosomes 9 and 22. This translocation produces a small Philadelphia chromosome, which contains the Bcr-Abl oncogene. The Bcr-Abl oncogene encodes the BCR-ABL protein, upregulates various signaling pathways (JAK-STAT, MAPK/ERK, and PI3K/Akt/mTOR), and out of which the specifically highly active pathway is the PI3K/Akt/mTOR pathway. Among early treatments for CML, tyrosine kinase inhibitors (TKIs) were found to be the most effective, but drug resistance against kinase inhibitors led to the discovery of novel alternative therapies. At this point, the PI3K/Akt/mTOR pathway components became new targets due to stimulation of this pathway in TKIs-resistant CML patients. The current review article deals with reviewing the scientific literature on the PI3K/Akt/mTOR pathway inhibitors listed in the National Cancer Institute (NCI) drug dictionary and proved effective against multiple cancers. And out of those enlisted inhibitors, the US FDA has also approved some PI3K inhibitors (Idelalisib, Copanlisib, and Duvelisib) and mTOR inhibitors (Everolimus, Sirolimus, and Temsirolimus) for cancer therapy. So far, several inhibitors have been tested, and further investigations are still ongoing. Even in Imatinib, Nilotinib, and Ponatinib-resistant CML cells, a dual PI3K/mTOR inhibitor, BEZ235, showed antiproliferative activity. Therefore, by considering the literature data of these reviews and further examining some of the reported inhibitors, which proved effective against the PI3K/Akt/mTOR signaling pathway in multiple cancers, may improve the therapeutic approaches towards TKI-resistant CML cells where the respective signaling pathway gets upregulated.