Comparative safety and efficacy of tyrosine kinase inhibitors (TKIs) in the treatment setting of different types of leukemia, and different types of adenocarcinoma

Efficacy and safety of FLT3 inhibitors in monotherapy of hematological and solid malignancies: a systemic analysis of clinical trials

Introduction: FLT3 mutations are closely associated with the occurrence of hematological and solid malignancies, especially with acute myeloid leukemia. Currently, several FLT3 inhibitors are in clinical trials, and some have been applied in clinic. However, the safety, efficacy and pharmacodynamics of these FLT3 inhibitors have not been systemically analyzed before. Methods: We searched and reviewed clinical trial reports on the monotherapy of 13 FLT3 inhibitors, including sorafenib, lestaurtinib, midostaurin, gilteritinib, quizartinib, sunitinib, crenolanib, tandutinib, cabozantinib, pexidartinib, pacritinib, famitinib, and TAK-659 in patients with hematological and solid malignancies before May 31, 2023. Results: Our results showed the most common adverse events (AEs) were gastrointestinal adverse reactions, including diarrhea, hand-foot syndrome and nausea, while the most common hematological AEs were febrile neutropenia, anemia, and thrombocytopenia. Based on the published data, the mean overall survival (OS) and the mean progression-free survival (PFS) were 9.639 and 5.905 months, respectively. The incidence of overall response rate (ORR), complete remission (CR), partial response (PR), and stable disease (SD) for all these FLT3 inhibitors was 29.0%, 8.7%, 16.0%, and 42.3%, respectively. The ORRs of FLT3 inhibitors in hematologic malignancies and solid tumors were 40.8% and 18.8%, respectively, indicating FLT3 inhibitors were more effective for hematologic malignancies than for solid tumors. In addition, time to maximum plasma concentration (Tmax) in these FLT3 inhibitors ranged from 0.7-12.0 hours, but the elimination half-life (T1/2) range was highly variable, from 6.8 to 151.8 h. Discussion: FLT3 inhibitors monotherapy has shown significant anti-tumor effect in clinic, and the effectiveness may be further improved through combination medication.

Expression of proliferation-related genes in BM-MSC-treated ALL cells in hypoxia condition is regulated under the influence of epigenetic factors in-vitro

Mesenchymal stem cells affect ALL cell biology under hypoxic conditions. We studied survival, proliferation, expression, and promoter methylation levels of essential genes involved in expanding MOLT-4 cells co-cultured with BM-MSC under the hypoxic condition. Here, MOLT-4 cells were co-cultured with BMMSCs under hypoxic conditions. First, the apoptosis rate was evaluated by Flow cytometry. Then, MOLT-4 cells' proliferation rate was assessed using MTT assay, and the expressions and methylation rates of genes were determined by qRT-PCR and MS-qPCR, respectively. The results showed that although MOLT-4 cells proliferation and survival rates were reduced under hypoxic conditions, this reduction was not statistically significant. Also, we showed that hypoxic conditions caused upregulation of candidate genes and affected their methylation status. Besides, it was revealed that Pontin was downregulated, while KDM3A, SKP2, and AURKA had an upward trend in the presence of MOLT-4 cells plus BM-MSC. The co-culture of leukemia cells with BMMSCs under hypoxic conditions may be a potential therapeutic approach for ALL.

Co-delivery Systems of Multiple Drugs Using Nanotechnology for Future Cancer Therapy

Cancer treatments have improved significantly during the last decade but are not yet satisfactory. Combination therapy is often administered to improve efficacy and safety. Drug delivery systems can also improve efficacy and safety. To control the spatiotemporal distribution of drugs, nanotechnology involving liposomes, solid lipid nanoparticles, and polymeric micelles has been developed. Co-delivery systems of multiple drugs are a promising approach to combat cancer. Synergistic effects and reduced side effects are expected from the use of co-delivery systems. In this review, we summarize various co-delivery systems for multiple drugs, including small-molecule drugs, nucleic acids, genes, and proteins. Co-delivery of drugs with different properties is relatively difficult, but some researchers have succeeded in developing such co-delivery systems. Environment-responsive carrier designs can control the release of cargos. Although their preparation is more complicated than that of mono-delivery systems, co-delivery systems can simplify clinical procedures and improve patient QOL.

In vitro and ex vivo anti‑tumor effect and mechanism of Tucatinib in leukemia stem cells and ABCG2‑overexpressing leukemia cells

Leukemia stem cells (LSCs), which evade standard chemotherapy, may lead to chemoresistance and disease relapse. The overexpression of ATP-binding cassette subfamily G member 2 (ABCG2) is an important determinant of drug resistance in LSCs and it can serve as a marker for LSCs. Targeting ABCG2 is a potential strategy to selectively treat and eradicate LSCs, and, hence, improve leukemia therapy. Tucatinib (Irbinitinib) is a novel tyrosine kinase inhibitor, targeting ErbB family member HER2, and was approved by the Food and Drug Administration in April 2020, and in Switzerland in May 2020 for the treatment of HER2-positive breast cancer. In the present study, the results demonstrated that tucatinib significantly improved the efficacy of conventional chemotherapeutic agents in ABCG2-overexpressing leukemia cells and primary leukemia blast cells, derived from patients with leukemia. In addition, tucatinib markedly decreased the proportion of leukemia stem cell-like side population (SP) cells. In SP cells, isolated from leukemia cells, the intracellular accumulation of Hoechst 33342, which is an ABCG2 substrate, was significantly elevated by tucatinib. Furthermore, tucatinib notably inhibited the efflux of [³H]-mitoxantrone and, hence, there was a higher level of [³H]-mitoxantrone in the HL60/ABCG2 cell line. The result from the ATPase assay revealed that tucatinib may interact with the drug substrate-binding site and stimulated ATPase activity of ABCG2. However, the protein expression level and cellular location of ABCG2 were not affected by tucatinib treatment. Taken together, these data suggested that tucatinib could sensitize conventional chemotherapeutic agents, in ABCG2-overexpressing leukemia cells and LSCs, by blocking the pump function of the ABCG2 protein. The present study revealed that combined treatment with tucatinib and conventional cytotoxic agents could be a potential therapeutic strategy in ABCG2-positive leukemia.

Metastatic heterogeneity of breast cancer: Molecular mechanism and potential therapeutic targets

Breast cancer is one of the most common malignancies among women throughout the world and is the major cause of most cancer-related deaths. Several explanations account for the high rate of mortality of breast cancer, and metastasis to vital organs is identified as the principal cause. Over the past few years, intensive efforts have demonstrated that breast cancer exhibits metastatic heterogeneity with distinct metastatic precedence to various organs, giving rise to differences in prognoses and responses to therapy in breast cancer patients. Bone, lung, liver, and brain are generally accepted as the primary target sites of breast cancer metastasis. However, the underlying molecular mechanism of metastatic heterogeneity of breast cancer remains to be further elucidated. Recently, the advent of novel genomic and pathologic approaches as well as technological breakthroughs in imaging analysis and animal modelling have yielded an unprecedented change in our understanding of the heterogeneity of breast cancer metastasis and provided novel insight for establishing more effective therapeutics. This review summarizes recent molecular mechanisms and emerging concepts on the metastatic heterogeneity of breast cancer and discusses the potential of identifying specific molecules against tumor cells or tumor microenvironments to thwart the development of metastatic disease and improve the prognosis of breast cancer patients.

Mitogen-activated protein kinase (MEK) inhibitors to treat melanoma alone or in combination with other kinase inhibitors

INTRODUCTION

Malignant melanoma (MM) is an aggressive disease with a rapidly rising incidence due to neoplasm of melanocytes. Molecular targeted therapies have demonstrated lower toxicity and improved overall survival versus conventional therapies of MM. The revealing of mutations in the BRAF/MEK/ERK pathway has led to the development of BRAF inhibitors such as vemurafenib and dabrafenib for the treatment of cutaneous MM. Though, progression of resistance to these agents has prompted attempts to target downstream proteins in this pathway. Trametinib, a MEK1/2 inhibitor, was approved in 2013 for the treatment of BRAF V600E/K mutation-positive unresectable or metastatic cutaneous melanoma patients. Areas covered: The aim of the current review is to present an update on the role of MEK in progressive melanomas and summarize latest results of clinical studies with innovative MEK inhibitors and/or combined approaches with other kinase inhibitors such as BRAF inhibitors in the treatment of MM. Expert opinion: Two combined treatments (i.e. trametinib plus dabrafenib and vemurafenib plus cobimetinib) target two different kinases in the BRAF/MEK/ERK pathway. The simultaneous prohibition of both MEK and BRAF is associated with more durable response rate than BRAF monotherapy and can overcome acquired resistance.