Cytotoxic Effects of Some Flavonoids and Imatinib on the K562 Chronic Myeloid Leukemia Cell Line: Data Analysis Using the Combination Index Method

Discovery of Potent Isoquinolinequinone N-Oxides to Overcome Cancer Multidrug Resistance

Multidrug resistance (MDR) of human tumors has resulted in an immediate need to develop appropriate new drugs. This work outlines the development of 20 potent IQQ N-oxide derivatives in two isomeric families, both exhibiting nanomolar GI50 against human tumor cell lines. Preliminary NCI-60 tumor screening sees the C(6) isomers achieve a mean GI50 > 2 times lower than the corresponding C(7) isomers. MDR evaluation of nine selected compounds reveals that each presents lower GI50 concentrations in two MDR tumor cell lines. Four of the series display nanomolar GI50 values against MDR cells, having selectivity ratios up to 2.7 versus the sensitive (parental) cells. The most potent compound 25 inhibits the activity of drug efflux pumps in MDR cells, causes significant ROS accumulation, and potently inhibits cell proliferation, causing alterations in the cell cycle profile. Our findings are confirmed by 3D spheroid models, providing new candidates for studies against MDR cancers.

Natural compounds combined with imatinib as promising antileukemic therapy: An updated review

Natural products (NP) have been an alternative therapy for several diseases for centuries, and they also serve as an essential source of bioactive molecules, enhancing our drug discovery capacity. Among these NP, some phytochemicals have shown multiple biological effects, including anticancer activity, with higher effectiveness and less toxicity than actual treatments, suggesting their possible use on resilient human malignancies such as leukemia. Imatinib mesylate (Im) is a selective tyrosine kinase inhibitor widely used as an anticancer drug, the gold standard to attend chronic myeloid leukemia (CML). Nevertheless, resistance to this drug in patients with CML renders it insufficient to eliminate cells with Philadelphia chromosome (BCR/ABL+). Moreover, recent studies show that imatinib can induce genotoxic and chromosomic damage in some in vitro and in vivo models. These facts urge finding new therapeutic alternatives to increase the effectiveness of antileukemic treatment. Recent research has shown that the combined effects of phytochemicals with imatinib can improve the cytotoxicity or resensitized the resistant cells to this drug in diverse leukemia cell lines. Independent mechanisms of action among phytochemicals and imatinib include BCR/ABL regulation, downregulation of transcription factors, inhibition of anti-apoptotic and activation of pro-apoptotic proteins, apoptosis induction dependent- and independent of ROS-overproduction, membrane functions disruption, induction of cell cycle arrest, and cell death. This review summarizes and discusses the synergic effect of some phytochemicals combined with imatinib on leukemia cells and the mechanism of action proposed for these combinations, looking to contribute to developing new effective alternatives for leukemia treatment.

A review on phytochemicals as combating weapon for multidrug resistance in cancer

One can recognize multidrug resistance (MDR) and residue as a biggest difficulty in cancer specialist. Chemotherapy-resistant cancer may be successfully treated by combining MDR-reversing phytochemicals with anticancer drugs. Though, clinical application of phytochemicals either alone or in conjunction with chemotherapy is still in its early stages or requires more research to determine their safety and efficacy. In this review we highlighted topics related to MDR in cancer, including an introduction to subject, mechanism of action of efflux pump, specific proteins involved in drug resistance, altered drug targets, increased drug metabolism, and potential role of phytochemicals in overcoming drug resistance.

Biological evaluation of combinations of tyrosine kinase inhibitors with Inecalcitol as novel treatments for human chronic myeloid leukemia

Background

The use of tyrosine kinase inhibitors (TKIs) as a treatment for chronic myeloid leukemia (CML) has improved the natural history of the disease and increased the duration of survival. Tyrosine kinase inhibitors represent the success of target therapies that work on molecular targets, although some patients still have therapy failure. Vitamin D has antiproliferative, pro-apoptotic, and anti-angiogenic effects on cells, therefore it can be considered as a potential cancer preventative and treatment agent. Inecalcitol (TX-522) is the 14-epi-analogue of Calcitriol (1,25(OH)2-vitamin D3), and inhibits cancer cell proliferation more effectively than Calcitriol. This study was conducted to evaluate the antiproliferative and synergistic effects of the anticancer drugs Imatinib and Dasatinib in combinations with Inecalcitol on human chronic myeloid leukemia K-562 cells.

Method

The growth inhibitory activities of Inecalcitol, Imatinib, Dasatinib, and different combinations of one of the two drugs (Imatinib and Dasatinib) with Inecalcitol, were determined in vitro using MTT assay against K-562 cell line.

Results

Inecalcitol, Imatinib, and Dasatinib showed potent antiproliferative activities against K-562 cells with GI50 values of 5.6 µM, 0.327 µM, and 0.446 nM, respectively. Combinations of Imatinib or Dasatinib with different concentrations of Inecalcitol increased significantly the antiproliferative activities and potencies of both drugs (****p < 0.0001), with optimal GI50 values of 580 pM (Imatinib) and 0.51 pM (Dasatinib). Furthermore, the combination treatments showed synergistic interaction between the antileukemic drugs and Inecalcitol, with combination indices (CI) < 1.

Conclusion

The study demonstrated that the human chronic myeloid leukemia K-562 cells were subjected to a synergistic growth inhibitory impact when antileukemic drugs (Imatinib or Dasatinib) were combined with Inecalcitol, therefore, it is recommended that these combinations be viewed as promising novel antileukemic medications and used in place of individual medications with lower dosages and negligible side effects in the treatment of CML.

Carvacrol-Fabricated Chitosan Nanoparticle Synergistic Potential with Topoisomerase Inhibitors on Breast and Cervical Cancer Cells

Breast and cervical cancers are the most common heterogeneous malignancies in women. Chemotherapy with conventional drug delivery systems having several limitations along with development of multidrug resistance compelled us to seek out targeted therapeutics. Nanoparticles are suitable substitutes to circumvent multidrug resistance for the targeted treatment of cancer. The current study was aimed to investigate the anticancer effect of carvacrol-loaded chitosan nanoparticles with topoisomerase inhibitors. The average size of carvacrol-loaded chitosan nanoparticles was found to be 80 nm with 24.7 mV ζ-potential, and maximum absorbance was observed at 275 nm. Among all drug combinations, the carvacrol nanoparticles with the doxorubicin combination group exerted greater dose-dependent growth inhibition of both MCF-7 and HeLa cells as compared to single carvacrol nanoparticles and doxorubicin. Combination index values of carvacrol nanoparticles and the doxorubicin combination group showed a strong synergistic effect as they were found to be between 0.2 and 0.4, 0.31 for MCF-7 and 0.34 for HeLa cells. The carvacrol nanoparticles in combination with doxorubicin on MCF-7 cells reduced the dose 16.32-fold for carvacrol nanoparticles and 4.09-fold for doxorubicin at 6.23 μg/mL IC50, while on HeLa cells, this combination reduced the dose 13.18-fold for carvacrol nanoparticles and 3.83-fold for doxorubicin at 9.33 μg/mL IC50. As the dose reduction values were greater than 1, they indicated favorable dose reduction. It was concluded that the combination of carvacrol-loaded chitosan nanoparticles with topoisomerase inhibitors may represent an innovative and promising strategy to improve the efficacy, resistance, and targeted delivery of chemotherapeutics in cancer.

Binary Nanodrug-Delivery System Designed for Leukemia Therapy: Aptamer- and Transferrin-Codecorated Daunorubicin- and Luteolin-Coloaded Nanoparticles

Objective

This study aimed to develop a binary nanodrug-delivery system decorated with aptamers (APs) and transferrin (Tf) and loaded with daunorubicin (Drn) and luteolin (Lut) for the treatment of leukemia.

Methods

Oligonucleotide AP- and Tf-contaiing ligands were designed and synthesized separately. AP-decorated Drn-loaded nanoparticles (AP-Drn NPs) and Tf-Lut NPs were prepared by self-assembly. An AP- and Tf-codecorated Drn- and Lut-coloaded nanodrug-delivery system (AP/Tf-Drn/Lut NPs) was prepared by self-assembly of AP-Drn NPs and Tf-Lut NPs. In vitro and in vivo efficiency of the system was evaluated on leukemia cell line and cell-bearing mouse model in comparison with single ligand-decorated, single drug-loaded and free-drug formulations.

Results

AP/Tf-Drn/Lut NPs were spherical and nanosized (187.3±5.3 nm) and loaded with about 85% of drugs. In vitro cytotoxicity of AP/Tf-Drn/Lut NPs was remarkably higher than single ligand-decorated ones. Double drug-loaded AP/Tf-Drn/Lut NPs exhibited higher tumor-cell inhibition than single drug-loaded ones, which showed a synergic effect of the two drugs. AP/Tf-Drn/Lut NPs achieved the most efficient antileukemic activity and absence of toxicity in vivo.

Conclusion

The present study showed that AP/Tf-Drn/Lut NPs are a promising drug-delivery system for targeted treatment of leukemia, due to the synergic effect of the two drugs in this system. The limitations of this system include stability during large-scale production and application from bench to bedside.

Research Progress of Natural Small-Molecule Compounds Related to Tumor Differentiation

Tumor differentiation is a therapeutic strategy aimed at reactivating the endogenous differentiation program of cancer cells and inducing cancer cells to mature and differentiate into other types of cells. It has been found that a variety of natural small-molecule drugs can induce tumor cell differentiation both in vitro and in vivo. Relevant molecules involved in the differentiation process may be potential therapeutic targets for tumor cells. Compared with synthetic drugs, natural small-molecule antitumor compounds have the characteristics of wide sources, structural diversity and low toxicity. In addition, natural drugs with structural modification and transformation have relatively concentrated targets and enhanced efficacy. Therefore, using natural small-molecule compounds to induce malignant cell differentiation represents a more targeted and potential low-toxicity means of tumor treatment. In this review, we focus on natural small-molecule compounds that induce differentiation of myeloid leukemia cells, osteoblasts and other malignant cells into functional cells by regulating signaling pathways and the expression of specific genes. We provide a reference for the subsequent development of natural small molecules for antitumor applications and promote the development of differentiation therapy.

Therapeutic potential of flavonoids in cancer: ROS-mediated mechanisms

Cancer is a leading cause of morbidity and mortality around the globe. Reactive oxygen species (ROS) play contradicting roles in cancer incidence and progression. Antioxidants have attracted attention as emerging therapeutic agents. Among these are flavonoids, which are natural polyphenols with established anticancer and antioxidant capacities. Increasing evidence shows that flavonoids can inhibit carcinogenesis via suppressing ROS levels. Surprisingly, flavonoids can also trigger excessive oxidative stress, but this can also induce death of malignant cells. In this review, we explore the inherent characteristics that contribute to the antioxidant capacity of flavonoids, and we dissect the scenarios in which they play the contrasting role as pro-oxidants. Furthermore, we elaborate on the pathways that link flavonoid-mediated modulation of ROS to the prevention and treatment of cancer. Special attention is given to the ROS-mediated anticancer functions that (-)-epigallocatechin gallate (EGCG), hesperetin, naringenin, quercetin, luteolin, and apigenin evoke in various cancers. We also delve into the structure-function relations that make flavonoids potent antioxidants. This review provides a detailed perspective that can be utilized in future experiments or trials that aim at utilizing flavonoids or verifying their efficacy for developing new pharmacologic agents. We support the argument that flavonoids are attractive candidates for cancer therapy.

Phytochemicals reverse P-glycoprotein mediated multidrug resistance via signal transduction pathways

P-glycoprotein, encoded by ATP-binding cassette transporters B1 gene (ABCB1), renders multidrug resistance (MDR) during cancer chemotherapy. Several synthetic small molecule inhibitors affect P-glycoprotein (P-gp) transport function in MDR tumor cells. However, inhibition of P-gp transport function adversely accumulates chemotherapeutic drugs in non-target normal tissues. Moreover, most small-molecule P-gp inhibitors failed in the clinical trials due to the low therapeutic window at the maximum tolerated dose. Therefore, downregulation of ABCB1-gene expression (P-gp) in tumor tissues seems to be a novel approach rather than inhibiting its transport function for the reversal of multidrug resistance (MDR). Several plant-derived phytochemicals modulate various signal transduction pathways and inhibit translocation of transcription factors, thereby reverses P-gp mediated MDR in tumor cells. Therefore, phytochemicals may be considered an alternative to synthetic small molecule P-gp inhibitors for the reversal of MDR in cancer cells. This review discussed the role of natural phytochemicals that modulate ABCB1 expression through various signal transduction pathways in MDR cancer cells. Therefore, modulating the cell signaling pathways by phytochemicals might play crucial roles in modulating ABCB1 gene expression and the reversal of MDR.

Thymoquinone chemosensitizes human colorectal cancer cells to imatinib via uptake/efflux genes modulation

Imatinib (IM) is a pharmaceutical drug that inhibits tyrosine kinase enzymes that are responsible for the activation of many proteins by signal transduction cascades as c-Abl, c-Kit and the platelet-derived growth factor (PDGF) receptor. Thymoquinone (TQ) is an active constituent of Nigella sativa seeds. Thymoquinone benefits are attributed to its medicinal uses as antioxidant, anticancer and antimicrobial agent. This study aimed to investigate the impact of using TQ with IM in the HCT116 human colorectal cancer cell line model. The HCT116 cells were treated with IM or/and TQ in non-constant ratios, in which the fixed concentrations of TQ (5, 10 or 20 µmol/L) were co-treated with various concentrations of IM (7.5-120 µmol/L) for 24, 48 and 72 hours. Imatinib-TQ interaction was analysed using CompuSyn software. The IC50 values for IM were 105, 72 μmol/L after 48 and 72 hours, respectively, and were significantly reduced to 7.3, 7 and 5.5 μmol/L after combination with TQ (10 μmol/L) and to 5.8, 5.6 and 4.6 μmol/L after combination with TQ (20 μmol/L) to 24, 48 and 72 hours, respectively. The combination index (CI) and dose reduction index (DRI) values indicate a significant synergism in HCT-116 cells at different treatment time points. Thymoquinone significantly enhances the cellular uptake of IM in HCT116 cells in a time and concentration-dependent manner. A significant downregulation in ATP-binding cassette (ABC) subfamily B member 1 (ABCB1), ABC subfamily G member 2 (ABCG2) and human organic cation transporter 1 (hOCT1) genes was observed in the cells exposed to IM+TQ combination as compared to IM alone, which resulted in a substantial elevation in uptake/efflux ratio in combination group. In conclusion, TQ potentiates IM efficacy on HCT116 cells via uptake/efflux genes modulation.

Sinensetin: An Insight on Its Pharmacological Activities, Mechanisms of Action and Toxicity

Sinensetin, a plant-derived polymethoxylated flavonoid found in Orthosiphon aristatus var. aristatus and several citrus fruits, has been found to possess strong anticancer activities and a variety of other pharmacological benefits and promising potency in intended activities with minimal toxicity. This review aims to compile an up-to-date reports of published scientific information on sinensetin pharmacological activities, mechanisms of action and toxicity. The present findings about the compound are critically analyzed and its prospect as a lead molecule for drug discovery is highlighted. The databases employed for data collection are mainly through Google Scholar, PubMed, Scopus and Science Direct. In-vitro and in-vivo studies showed that sinensetin possessed strong anticancer activities and a wide range of pharmacological activities such as anti-inflammatory, antioxidant, antimicrobial, anti-obesity, anti-dementia and vasorelaxant activities. The studies provided some insights on its several mechanisms of action in cancer and other disease states. However, more detail mechanistic studies are needed to understand its pharmacological effects. More in vivo studies in various animal models including toxicity, pharmacokinetic, pharmacodynamic and bioavailability studies are required to assess its efficacy and safety before submission to clinical studies. In this review, an insight on sinensetin pharmacological activities and mechanisms of action serves as a useful resource for a more thorough and comprehensive understanding of sinensetin as a potential lead candidate for drug discovery.

Prodigiosin induced the caspase-dependent apoptosis in human chronic myelogenous leukemia K562 cell

Background and purpose:

Chronic myeloid leukemia (CML) as a myeloproliferative disease is characterized by increased cellularity of bone marrow. Implementing the latest treatment protocols is currently accompanied by serious and life-threatening side effects. There are worldwide attempts to find new effective and potent therapeutic agents with minimal side effects on CML patients. This in vitro study was carried out to discover the potential antiproliferative and apoptotic effects of naturally produced prodigiosin (PDG) on K562 cells as an accepted model of CML.

Experimental approach:

The anti-proliferative effect of PDG was measured by MTT assay. To highlight the mechanism of cytotoxicity, the apoptotic cell death pathway was investigated by morphological and biochemical assessments. The dual acridine orange/ethidium bromide staining technique and western blotting method were applied to assess the mechanism of the potential apoptotic impact of PDG on K562 cells.

Findings/Results:

PDG-induced time- and concentration-dependent anti-proliferative effects were revealed with an estimated IC₅₀ value of 54.06 μM. The highest cell viability reduction (60%) was recorded in cells, which were exposed to 100 μM concentration. Further assays demonstrated that in the dual acridine orange/ethidium bromide staining method the cell population in the late apoptosis phase was increased in a concentration-dependent manner, which was confirmed with remarkable DNA fragmentation.

Conclusion and implications:

We found that the PDG-induced apoptosis in K562 cells is mediated through the caspase-3 activation both in mRNA and protein levels. Our results suggest that PDG could be a potent compound for further pharmacokinetic and pharmacodynamics studies in the in vivo model of CML.

The Mediterranean Diet as source of bioactive compounds with multi-targeting anti-cancer profile

Many bioactive agents have been extracted from plants or belong to functional foods and have been considered in the treatment of serious and multifactorial diseases, such as cancer. In particular, this review is focused on the anti-cancer properties owned by several natural products typically from the Mediterranean area. In some regions of the South of Italy, a lower cancer incidence has been observed. There is increasing evidence that adherence to a Mediterranean dietary pattern correlates with reduced risk of several cancer types. This could be mainly attributed to the typical lifestyle aspects of the Mediterranean diet, such as high consumption of fruit and vegetables. In this review, the main natural products of the Mediterranean area are discussed, with particular attention on their anti-cancer properties endowed with multi-target profiles.