HL-37, a novel anthracene derivative, induces Ca(2+)-mediated apoptosis in human breast cancer cells

Room-Temperature, Copper-Free, and Amine-Free Sonogashira Reaction in a Green Solvent: Synthesis of Tetraalkynylated Anthracenes and In Vitro Assessment of Their Cytotoxic Potentials

The multifold Sonogashira coupling of a class of aryl halides with arylacetylene in the presence of an equivalent of Cs₂CO₃ has been accomplished using a combination of Pd(CH₃CN)₂Cl₂ (0.5 mol %) and cataCXium A (1 mol %) under copper-free and amine-free conditions in a readily available green solvent at room temperature. The protocol was used to transform several aryl halides and alkynes to the corresponding coupled products in good to excellent yields. The rate-determining step is likely to involve the oxidative addition of Ar-X. The green protocol provides access to various valuable polycyclic aromatic hydrocarbons (PAHs) with exciting photophysical properties. Among them, six tetraalkynylated anthracenes have been tested for their anticancer properties on the human triple-negative breast cancer (TNBC) cell line MDA-MB-231 and human dermal fibroblasts (HDFs). The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed to find out the IC₅₀ concentration and lethal dose. The compounds being intrinsically fluorescent, their cellular localization was checked by live cell fluorescence imaging. 4',6-Diamidino-2-phenylindole (DAPI) and propidium iodide (PI) staining was performed to check apoptosis and necrosis, respectively. All of these studies have shown that anthracene and its derivatives can induce cell death via DNA damage and apoptosis.

Design, synthesis, molecular modelling, and biological evaluation of novel substituted pyrimidine derivatives as potential anticancer agents for hepatocellular carcinoma

New anticancer agents are highly needed to overcome cancer cell resistance. A novel series of pyrimidine pyrazoline-anthracene derivatives (PPADs) (4a-t) were designed and synthesised. The anti-liver cancer activity of all compounds was screened in vitro against two hepatocellular carcinoma (HCC) cell lines (HepG2 and Huh-7) as well as normal fibroblast cells by resazurin assay. The designed compounds 4a-t showed a broad-spectrum anticancer activity against the two cell lines and their activity was more prominent on cancer compared to normal cells. Compound 4e showed high potency against HepG2 and Huh-7 cell lines ((IC₅₀=5.34 and 6.13 μg/mL, respectively) comparable to that of doxorubicin (DOX) activities. A structure activity relationship (SAR) has been investigated and compounds 4e, 4i, 4m, and 4q were the most promising anticancer agents against tested cell lines. These compounds induced apoptosis in HepG2 and Huh-7 cells through significant activation of caspase 3/7 at all tested concentrations. In conclusion, 4e could be a potent anticancer drug.

Ethanolic Extract of Senna velutina Roots: Chemical Composition, In Vitro and In Vivo Antitumor Effects, and B16F10-Nex2 Melanoma Cell Death Mechanisms

Cutaneous melanoma is among the most aggressive types of cancer, and its rate of occurrence increases every year. Current pharmacological treatments for melanoma are not completely effective, requiring the identification of new drugs. As an alternative, plant-derived natural compounds are described as promising sources of new anticancer drugs. In this context, the objectives of this study were to identify the chemical composition of the ethanolic extract of Senna velutina roots (ESVR), to assess its in vitro and in vivo antitumor effects on melanoma cells, and to characterize its mechanisms of action. For these purposes, the chemical constituents were identified by liquid chromatography coupled to high-resolution mass spectrometry. The in vitro activity of the extract was assessed in the B16F10-Nex2 melanoma cell line using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and based on the apoptotic cell count; DNA fragmentation; necrostatin-1 inhibition; intracellular calcium, pan-caspase, and caspase-3 activation; reactive oxygen species (ROS) levels; and cell cycle arrest. The in vivo activity of the extract was assessed in models of tumor volume progression and pulmonary nodule formation in C57Bl/6 mice. The chemical composition results showed that ESVR contains flavonoid derivatives of the catechin, anthraquinone, and piceatannol groups. The extract reduced B16F10-Nex2 cell viability and promoted apoptotic cell death as well as caspase-3 activation, with increased intracellular calcium and ROS levels as well as cell cycle arrest at the sub-G0/G1 phase. In vivo, the tumor volume progression and pulmonary metastasis of ESVR-treated mice decreased over 50%. Combined, these results show that ESVR had in vitro and in vivo antitumor effects, predominantly by apoptosis, thus demonstrating its potential as a therapeutic agent in the treatment of melanoma and other types of cancer.

The effect of combined exposure of 900 MHz radiofrequency fields and doxorubicin in HL-60 cells

Human promyelocytic leukemia HL-60 cells were pre-exposed to non-ionizing 900 MHz radiofrequency fields (RF) at 12 µW/cm² power density for 1 hour/day for 3 days and then treated with a chemotherapeutic drug, doxorubicin (DOX, 0.125 mg/L). Several end-points related to toxicity, viz., viability, apoptosis, mitochondrial membrane potential (MMP), intracellular free calcium (Ca²⁺) and Ca²⁺-Mg²⁺ -ATPase activity were measured. The results obtained in un-exposed and sham-exposed control cells were compared with those exposed to RF alone, DOX alone and RF+DOX. The results indicated no significant differences between un-exposed, sham-exposed control cells and those exposed to RF alone while treatment with DOX alone showed a significant decrease in viability, increased apoptosis, decreased MMP, increased Ca²⁺ and decreased Ca²⁺-Mg^2+-ATPase activity. When the latter results were compared with cells exposed RF+DOX, the data showed increased cell proliferation, decreased apoptosis, increased MMP, decreased Ca²⁺ and increased Ca²⁺-Mg²⁺-ATPase activity. Thus, RF pre-exposure appear to protect the HL-60 cells from the toxic effects of subsequent treatment with DOX. These observations were similar to our earlier data which suggested that pre-exposure of mice to 900 MHz RF at 120 µW/cm² power density for 1 hours/day for 14 days had a protective effect in hematopoietic tissue damage induced by subsequent gamma-irradiation.

Calpains as potential anti-cancer targets

INTRODUCTION

The intracellular signaling cysteine proteases, calpains (specifically the ubiquitous calpains 1 and 2), are involved in numerous physiological and pathological phenomena. Several works have highlighted the implication of calpains in processes crucial for cancer development and progression. For these reasons, calpains are considered by several authors as potential anti-cancer targets.

AREAS COVERED

How calpains are implicated in cancer formation and development, how these enzymes are deregulated in cancer cells and how these proteases could be targeted by anti-cancer drugs. Studies published in the last 10 years are focused on.

EXPERT OPINION

Targeting calpain activity with specific inhibitors could be a novel approach to limiting development of primary tumors and formation of metastases, by inhibiting tumor cell migration and invasion, which allows dissemination as well as tumor neovascularization, which in turn allows expansion. However, such drugs could interfere with anti-cancer treatments, as ubiquitous calpains play crucial roles in chemotherapy-induced apoptosis. For these reasons, drugs targeting calpains would have to be used selectively to avoid interference with other treatments and physiological processes. Further studies will be required concerning the other members of the calpain family and their potential implication in cancer development before considering treatments targeting their activity.