Phytol and Heptacosane Are Possible Tools to Overcome Multidrug Resistance in an In Vitro Model of Acute Myeloid Leukemia

Drug resistance is the ability of cancer cells to gain resistance to both conventional and novel chemotherapy agents, and remains a major problem in cancer therapy. Resistance mechanisms are multifactorial and involve more strictly pharmacological factors, such as P-glycoprotein (P-gp) and biological factors such as inhibitor of apoptosis proteins (IAPs) and the nuclear factor-kappa B (NF-kB) pathway. Possible therapeutic strategies for the treatment of acute myeloid leukemia (AML) have increased in recent years; however, drug resistance remains a problem for most pa-tients. Phytol and heptacosane are the major compounds of Euphorbia intisy essential oil (EO) which were demonstrated to inhibit P-gp in a multidrug resistant in vitro model of AML. This study investigated the mechanism by which phytol and heptacosane improve P-gp-mediated drug transport. Phytol suppresses the P-gp expression via NF-kB inhibition and does not seem to act on the efflux system. Heptacosane acts as a substrate and potent P-gp inhibitor, demonstrating the ability to retain the substrate doxorubicin inside the cell and enhancing its cytotoxic effects. Our results suggest that these compounds act as non-toxic modulators of P-gp through different mechanisms and are able to revert P-gp-mediated drug resistance in tumor cells

Antitumor Mechanism of the Essential Oils from Two Succulent Plants in Multidrug Resistance Leukemia Cell

Drug resistance remains a major challenge in the treatment of cancer. The multiplicity of the drug resistance determinants raises the question about the optimal strategies to deal with them. Essential oils showed to inhibit the growth of different tumor cell types. Essential oils contain several chemical classes of compounds whose heterogeneity of active moieties can help prevent the development of drug resistance. In the present paper, we analyzed, by gas chromatography-mass spectrometry the chemical composition of the essential oil of the leaves of Kalanchoe beharensis obtained by hydrodistillation and compared the chemical composition of its essential oil with that of Cyphostemma juttae. Our results demonstrated the anticancer and proapoptotic activities of both species against acute myeloid leukemia on an in vitro model and its multidrug resistant variant involving NF-κB pathway. The essential oils of both species produced a significant decrease in many targets of NF-κB both at mRNA and protein levels. The results corroborate the idea that essential oils may be a good alternative to traditional drugs in the treatment of cancer, especially in drug resistant cancer

Antitumor Effect of Glandora rosmarinifolia (Boraginaceae) Essential Oil through Inhibition of the Activity of the Topo II Enzyme in Acute Myeloid Leukemia

It was previously shown that the antitumor and cytotoxic activity of the essential oil (EO) extracted from the aerial parts of Glandora rosmarinifolia appears to involve a pro-oxidant mechanism in hepatocellular carcinoma (HCC) and in triple-negative breast cancer (TNBC) cell lines. Its most abundant compound is a hydroxy-methyl-naphthoquinone isomer. Important pharmacological activities, such as antitumor, antibacterial, antifungal, antiviral and antiparasitic activities, are attributed to naphthoquinones, probably due to their pro-oxidant or electrophilic potential; for some naphthoquinones, a mechanism of action of topoisomerase inhibition has been reported, in which they appear to act both as catalytic inhibitors and as topoisomerase II poisons. Our aim was to evaluate the cytotoxic activity of the essential oil on an acute myeloid leukemia cell line HL-60 and on its multidrug-resistant (MDR) variant HL-60R and verify its ability to interfere with topoisomerase II activity. MTS assay showed that G. rosmarinifolia EO induced a decrease in tumor cell viability equivalent in the two cell lines; this antitumor effect could depend on the pro-oxidant activity of EO in both cell lines. Furthermore, G. rosmarinifolia EO reduced the activity of Topo II in the nuclear extracts of HL-60 and HL-60R cells, as inferred from the inability to convert the kinetoplast DNA into the decatenated form and then not inducing linear kDNA. Confirming this result, flow cytometric analysis proved that EO induced a G0-G1 phase arrest, with cell reduction in the S-phase. In addition, the combination of EO with etoposide showed a good potentiation effect in terms of cytotoxicity in both cell lines. Our results highlight the antitumor activity of EO in the HL-60 cell line and its MDR variant with a peculiar mechanism as a Topo II modulator. Unlike etoposide, EO does not cause stabilization of a covalent Topo II-DNA intermediate but acts as a catalytic inhibitor. These data make G. rosmarinifolia EO a potential anticancer drug candidate due to its cytotoxic action, which is not affected by multidrug resistance

Can NF-κB Be Considered a Valid Drug Target in Neoplastic Diseases? Our Point of View

Multidrug resistance (MDR), of the innate and acquired types, is one of major problems in treating tumor diseases with a good chance of success. In this review, we examine the key role of nuclear factor-kappa B (NF-κB) to induce MDR in three tumor models characterized precisely by innate or acquired MDR, in particular triple negative breast cancer (TNBC), hepatocellular carcinoma (HCC), and acute myeloid leukemia (AML). We also present different pharmacological approaches that our group have employed to reduce the expression/activation of this transcriptional factor and thus to restore chemo-sensitivity. Finally, we examine the latest scientific evidence found by other groups, the most significant clinical trials regarding NF-κB, and new perspectives on the possibility to consider this transcriptional factor a valid drug target in neoplastic diseases

Potential role of the natural multi-targeted agent curcumin in the treatment of oral diseases.

We critically review the current data on the therapeutic effects and basic biological activities of the natural compound curcumin on various oral diseases: a sound experimental evidence appears to support its possible use against relevant pathologies which include cancer, radiotherapy- and chemotherapy-induced mucositis, lichen planus and periodontitis. This versatility of curcumin depends on its ability of interacting with multiple targets, though inhibition of the transcription factor NF-kB can be identified as one of the principal mechanisms. The therapeutic potentialities of curcumin in oral medicine have, however, to be further verified, in particular by more human ad hoc in vivo studies. An important aspect that remains to resolve is that of improving by adequate approaches the topical or systemic delivery of the drug to the target tissues. At present there is also a very active search for the synthesis of new curcumin derivatives endowed with improved pharmacokinetic and pharmacodynamic characteristics

Expression of a specific Thymidylate synthase polimorfic allele in metastatic colorectal patients is regulated by Myeloid Zinc Finger 1.

Thymidylate Synthase (TS) is the target enzyme for fluoropyrimidine anticancer drugs. Its expression is regulated by the number of functional upstream stimulatory factor (USF) E box consensus elements present on its 5’ untranslated region. To date are known different polymorphisms, the first one consisting of 2 or 3 repeat of a 28 bp sequence, a further single nucleotide polymorphism (SNP) consisting in a G>C substitution within the second repeat of 3R (3RG>3RC) and recently it has been identified an additional SNP a G>C substitution at the 12th nucleotide in the first repeat of the 2R allele (2RG>2RC). These polymorphisms can influence TS expression, in particular 3R/3R genotype and the presence of 3RG alleles are associated to an increased transcriptional activity and to higher TS levels. The sequence of promoter region of colorectal cancer (CRC) samples was subjected to an in silico analysis (http://www.cbrc.jp/research/db/TFSEARCH.html) to search for all potential transcription factors binding this region. We found that Myeloid zinc finger 1(MZF-1) binds the analyzed consensus. By the literature it is known that this factor induces invasion and in vivo metastasis in CRC, so we investigated a possible correlation between TS and MZF-1 expression in the same pathological samples. Materials and Methods: we analyzed the distribution of these polimorphisms in a group of 68 healthy Caucasian subjects, in the normal tissue, in primary tumour and in liver metastasis of 13 CRC patients. Tandem repeat length and the presence of SNP was determined by direct sequencing of genomic DNA. TS and MZF 1 expression were analyzed by immunohistochemistry. Results: In healthy population the allele frequency was respectively 2RG(35%) 3RG (44%) 3RC (21%), in colorectal patients while both primary that normal and metastatic samples showed the same genotype: 2RG/3RG. TS and MZF-1 expression were related and gradually increased from normal tissue (negative) to the primary tumour (focally positive) in the metastases (overexpressing). Conclusions: These unexpected results lead to the hypothesis of a genetic selection towards a more aggressive disease and enough suggest that regardless of genotype other factors are involved in regulation of TS expression as MZF 1, therefore the only genetic marker is not a valid predictor of eventual fluoropyrimidine response

Patterns of Innate or Acquired Resistance to Anticancer Drugs: Our Experience to Overcome It

Drug resistance, which is often of a multiple type, can be defined as the ability of cancer cells to obtain resistance to both conventional and novel chemotherapy agents. It remains a major problem to solve in cancer therapy. The mechanisms of resistance are multifactorial, and in our cellular models of acute myeloid leukemia, hepatocellular carcinoma, and triple-negative breast cancer, it involves the NF-κB pathway. In our opinion, multitarget molecules can be considered as privileged compounds capable of attacking and reversing the resistant phenotype. In the phenomena of both innate and acquired drug resistance that we have been studying since 1998 to today and up to 2016 under the guidance of Professor Natale D’Alessandro, more strictly pharmacological factors are certainly involved. These factors include P-glycoprotein and biological factors such as inhibitory proteins; apoptosis; the Raf-1 kinase inhibitor protein, an important tumor suppressor and metastasis inhibitor, which enhances drug-induced apoptosis of cancer cells; and Yin Yang, a transcription factor involved in drug resistance