Exploring the Antitumor Potential of Copper Complexes Based on Ester Derivatives of Bis(pyrazol-1-yl)acetate Ligands.

Bis(pyrazol-1-yl)acetic acid (HC(pz)2COOH) and bis(3,5-dimethyl-pyrazol-1-yl)acetic acid (HC(pzMe2)2COOH) were converted into the methyl ester derivatives 1 (LOMe) and 2 (L2OMe), respectively, and were used for the preparation of Cu(I) and Cu(II) complexes 3-10. The copper(II) complexes were prepared by the reaction of CuCl2·2H2O or CuBr2 with ligands 1 and 2 in methanol solution. The copper(I) complexes were prepared by the reaction of Cu[(CH3CN)4]PF6 and 1,3,5-triaza-7-phosphaadamantane (PTA) or triphenylphosphine with LOMe and L2OMe in acetonitrile solution. Synchrotron radiation-based complementary techniques (XPS, NEXAFS, and XAS) were used to investigate the electronic and molecular structures of the complexes and the local structure around copper ions in selected Cu(I) and Cu(II) coordination compounds. All Cu(I) and Cu(II) complexes showed a significant in vitro antitumor activity, proving to be more effective than the reference drug cisplatin in a panel of human cancer cell lines, and were able to overcome cisplatin resistance. Noticeably, Cu complexes appeared much more effective than cisplatin in 3D spheroid cultures. Mechanistic studies revealed that the antitumor potential did not correlate with cellular accumulation but was consistent with intracellular targeting of PDI, ER stress, and paraptotic cell death induction.

Insight on pyrimido[5,4-g]indolizine and pyrimido[4,5-c]pyrrolo[1,2-a]azepine systems as promising photosensitizers on malignant cells.

Searching for new small molecules as photosensitizing agents, we have developed a class of twenty-five pyrimido[5,4-g]indolizine and pyrimido[4,5-c]pyrrolo[1,2-a]azepines with a good substitution pattern defining a versatile synthetic pathway to approach the title ring system. All compounds were evaluated for their photocytotoxicity on a triple negative human breast cancer cell line (MDA-MB-231) in the dark and under UVA light (2.0 J/cm2). The most effective compounds exhibited a photoantiproliferative activity with IC50 values up to nanomolar ranges. Interestingly, these new developed compounds showed high selectivity towards cancerous cells with respect to non-cancerous ones. Moreover, four representative derivatives demonstrated to be phototoxic also against an additional human HER2 positive breast cancer cell line (HCC1954), and against the HER2 positive vesical cancer cell line (T24) harboring Hras mutation. Mechanistic studies performed in triple negative MDA-MB-231 cancer cells revealed the ability of the compounds to increase reactive oxygen species (ROS) production and to induce a thiol redox stress, thus triggering cancer cell death through apoptosis. Apoptotic cell death was also induced in highly aggressive and metastatic HER2 positive Hras mutated T24-treated bladder cancer cells. Overall, our data confirm that these new small photosensitizing agents may represent very promising candidates for phototherapy application against highly aggressive and resistant cancers.

Cu(I) and Cu(II) Complexes Based on Lonidamine-Conjugated Ligands Designed to Promote Synergistic Antitumor Effects.

Bis(pyrazol-1-yl)- and bis(3,5-dimethylpyrazol-1-yl)-acetates were conjugated with the 2-hydroxyethylester and 2-aminoethylamide derivatives of the antineoplastic drug lonidamine to prepare Cu(I) and Cu(II) complexes that might act through synergistic mechanisms of action due to the presence of lonidamine and copper in the same chemical entity. Synchrotron radiation-based complementary techniques [X-ray photorlectron spectroscopy and near-edge X-ray absorption fine structure (NEXAFS)] were used to characterize the electronic and molecular structures of the complexes and the local structure around the copper ion (XAFS) in selected complexes. All complexes showed significant antitumor activity, proving to be more effective than the reference drug cisplatin in a panel of human tumor cell lines, and were able to overcome oxaliplatin and multidrug resistance. Noticeably, these Cu complexes appeared much more effective than cisplatin against 3D spheroids of pancreatic PSN-1 cancer cells; among these, PPh3-containing Cu(I) complex 15 appeared to be the most promising derivative. Mechanistic studies revealed that 15 induced cancer cell death by means of an apoptosis-alternative cell death.

Phytochemical Fingerprinting and In Vitro Bioassays of the Ethnomedicinal Fern Tectaria coadunata (J. Smith) C. Christensen from Central Nepal.

Tectaria coadunata, an ethnomedicinal fern used in Nepal to treat a large number of diseases, has been poorly studied with regard to its phytochemical composition and possible bioactivity. This study was performed with the aim of supporting traditional medicine as a new source of bioactive constituents. Phytochemical compositions of methanol extracts were determined by nuclear magnetic resonance (NMR), liquid chromatography-diode array detector-mass spectrophotometry (LC-DAD-MS), and liquid chromatography-fluorescence-mass spectrometry. Quali-quantitative data revealed large amount of procyanidins, mainly of the A-type, as well as eriodictyol-7-O-glucuronide and luteolin-7-O-glucoronide as main constituents. The antioxidant, cytotoxic, and inhibitory activity of five enzymes that are implicated in human diseases was evaluated for the extract and fractions. High free-radical scavenging activity in 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays and inhibitory activities against cholinesterases and tyrosinase were observed. Furthermore, a moderate cytotoxic effect was observed on the 2008 and BxPC3 cell lines. Overall results showed potential usefulness of this fern as a source of phytochemicals for pharmaceutical uses.

Sesquiterpene rich essential oil from Nepalese Bael tree (Aegle marmelos (L.) Correa) as potential antiproliferative agent.

Aegle marmelos (L.) Corr. (Rutaceae), also known as Bael tree, is an herbal traditional remedy in the South East Asia. In the present work, the leaf essential oil distilled from a population collected in Nepal was analyzed for the chemical composition by GC-MS showing different phytochemical constituents compared with literature data. The obtained oil was rich in sesquiterpenes, mainly ß-Caryophyllene (26%), whereas monoterpenes, known in literature as the major components, were present in little amounts. Due to richness in sesquiterpenes which are promising as anticancer drugs, the oil was tested against several human tumor cell lines namely pancreatic (PSN-1), colon (LoVo), lung (H157) and ovarian (2008) cells showing IC50 of 5.6 µg/mL, 6.5 µg/mL, 6.7 µg/mL and 2.3 µg/mL, respectively. In vivo distribution of oil was studied with a dose of 41.5 mg/kg in mice allowing the quantification of ß-Caryophyllene, α-Humulene, γ-Muurulene and ar-Curcumene at 30 and 60 min after oral administration. Sesquiterpene were found in higer amount in, liver, kidney and heart whereas lung and blood contained lower levels. The tissue distribution study demonstrated that active sesquiterpenoids of the oil can efficiently reach different organs.

Phytochemical investigations and antiproliferative secondary metabolites from Thymus alternans growing in Slovakia.

CONTEXT: Thymus alternans Klokov (Lamiaceae) is a neglected species of the genus Thymus (Sect. Serpyllum) endemic to Carpathian area, where it is used as a flavouring agent and for medicinal purposes. OBJECTIVE: The aim of the work was to identify antiproliferative constituents from the flowering aerial parts of this plant. MATERIALS AND METHODS: Thymus alternans extracts were analyzed by HPLC-MSn and subjected to extensive chromatographic separations. The isolated compounds (phenolics and triterpenes) were structurally elucidated by MS and 1D and 2D NMR experiments. Essential oil (EO) composition was determined by GC-FID and GC-MS. Six purified triterpenes and EO were assayed for in vitro antiproliferative activity against a panel of human cancer cells, namely, breast (MDA-MB 231), colon (HCT-15 and HCT116), lung (U1810), pancreatic (BxPC3), melanoma (A375) and cervical carcinoma (A431) cells. RESULTS: The structures of the isolated compounds were achieved on the basis of H-NMR and MS experiments. Luteolin-4'-O-ß-d-glucopyranoside (P1), chrysoeriol-7-O-ß-d-glucopyranoside (P2), chrysoeriol-5-O-ß-d-glucopyranoside (P3), apigenin-7-O-ß-d-glucopyranoside (P4), rosmarinic acid (P5), rosmarinic acid-3'-O-ß-d-glucopyranoside (P6), caffeic acid-3-O-ß-d-glucopyranoside (P7), 3α-hydroxy-urs-12,15-diene (T1), α-amyrin (T2), ß-amyrin (T3), isoursenol (T4), epitaraxerol (T5), and oleanolic acid (T6). GC-MS analysis revealed that the EO of T. alternans was devoid of phenols and belonged to the nerolidol-chemotype, that is typical of the Sect. Serpyllum. The six purified triterpenes (T1-T6) were active with IC50 ranging from 0.5 to 5 µM being comparable or better than those of reference compounds betulinic acid and cisplatin. The EO exhibited significant effects on A375, MDA-MB 231 and HCT116 cell lines with IC50 in the range of 5-8 µg/mL. CONCLUSION: The reported results suggest that T. alternans can be considered as a good source of phytoconstituents with possible importance in the pharmaceutical field.

Selenium-containing chrysin and quercetin derivatives: attractive scaffolds for cancer therapy.

Selenium-containing chrysin (SeChry) and 3,7,3',4'-tetramethylquercetin (SePQue) derivatives were synthesized by a microwave-based methodology. In addition to their improvement in terms of DPPH scavenging and potential GPx-like activities, when tested in a panel of cancer cell lines both selenium-derivatives revealed consistently to be more cytotoxic when compared with their oxo and thio-analogues, evidencing the key role of selenocabonyl moiety for these activities. In particular, SeChry elicited a noteworthy cytotoxic activity with mean IC50 values 18- and 3-fold lower than those observed for chrysin and cisplatin, respectively. Additionally, these seleno-derivatives evidenced an ability to overcome cisplatin and multidrug resistance. Notably, a differential behavior toward malignant and nonmalignant cells was observed for SeChry and SePQue, exhibiting higher selectivity indexes when compared with the chalcogen-derivatives and cisplatin. Our preliminary investigation on the mechanism of cytotoxicity of SeChry and SePQue in MCF-7 human mammary cancer cells demonstrated their capacity to efficiently suppress the clonal expansion along with their ability to hamper TrxR activity leading to apoptotic cell death.

Role of zinc trafficking in male fertility: from germ to sperm.

STUDY QUESTION: What are the dynamics of zinc (Zn) trafficking in sperm, at the testicular, epididymal and ejaculate levels? SUMMARY ANSWER: Zn transporters are peculiarly expressed in the cells of the germ line and Zn uptake is maximal at the post-epididymal phase, where Zn is involved in the regulation of sperm functions. WHAT IS KNOWN ALREADY: Zn is known to influence several phases of sperm life, from germ cell development to spermiation. Zn trafficking across the membrane is allowed by specific families of transporters known as the ZnTs, which are involved in effluent release, and the Zips, which mediate uptake. STUDY DESIGN, SIZE, DURATION: We enrolled 10 normozoospermic healthy participants in an infertility survey programme, as well as 5 patients affected by testicular germ cell cancer, and 18 patients presenting with obstructive azoospermia, without mutations of the CFTR gene, and undergoing assisted reproductive technologies. PARTICIPANTS/MATERIALS, SETTING, METHODS: The research study was performed at our University Clinic. Semen samples, or biopsies or fine needle aspirates from the testis or epididymis, were obtained from each of the participants. Protein expression of main members of the ZnT and Zip families of Zn transporters was examined in human testis and epididymis samples by immunofluorescence. Quantification of sperm Zn content was performed by flow cytometry, atomic absorption spectrometry (AA) and autometallography. MAIN RESULTS AND THE ROLE OF CHANCE: Intratubular cells of the germ line displayed a high redundancy of Zip family members involved in Zn uptake, while ZnT transporters were more represented in epididymis. Testicular and epididymal spermatozoa contained less Zn than ejaculated spermatozoa (2.56 ± 0.51 and 12.58 ± 3.16 versus 40.48 ± 12.71 ng Zn/10(6)cells, respectively). Gain of hypermotility and acrosomal reaction were significantly linked to the loss of Zn content in ejaculated spermatozoa. LIMITATIONS, REASONS FOR CAUTION: This was an ancillary study performed on a small cohort of normozoospermic subjects. Although these results clarify the Zn trafficking during different phases of sperm life, no conclusive information can be drawn about the fertilizing potential of sperm, and the overall pregnancy outcomes, after Zn supplementation. WIDER IMPLICATIONS OF THE FINDINGS: Our data disclose the dynamics of Zn trafficking during over the sperm lifespan. STUDY FUNDING/COMPETING INTEREST(S): No external funding was sought or obtained for this study. No conflict of interest is declared.

Selenium induces a multi-targeted cell death process in addition to ROS formation.

Selenium compounds inhibit neoplastic growth. Redox active selenium compounds are evolving as promising chemotherapeutic agents through tumour selectivity and multi-target response, which are of great benefit in preventing development of drug resistance. Generation of reactive oxygen species is implicated in selenium-mediated cytotoxic effects on cancer cells. Recent findings indicate that activation of diverse intracellular signalling leading to cell death depends on the chemical form of selenium applied and/or cell line investigated. In the present study, we aimed at deciphering different modes of cell death in a single cell line (HeLa) upon treatment with three redox active selenium compounds (selenite, selenodiglutathione and seleno-DL-cystine). Both selenite and selenodiglutathione exhibited equipotent toxicity (IC50 5 µM) in these cells with striking differences in toxicity mechanisms. Morphological and molecular alterations provided evidence of necroptosis-like cell death in selenite treatment, whereas selenodiglutathione induced apoptosis-like cell death. We demonstrate that selenodiglutathione efficiently glutathionylated free protein thiols, which might explain the early differences in cytotoxic effects induced by selenite and selenodiglutathione. In contrast, seleno-DL-cystine treatment at an IC50 concentration of 100 µM induced morphologically two distinct different types of cell death, one with apoptosis-like phenotype, while the other was reminiscent of paraptosis-like cell death, characterized by induction of unfolded protein response, ER-stress and occurrence of large cytoplasmic vacuoles. Collectively, the current results underline the diverse cytotoxic effects and variable potential of redox active selenium compounds on the survival of HeLa cells and thereby substantiate the potential of chemical species-specific usage of selenium in the treatment of cancers.

Effects of the antioxidant Pycnogenol on cellular redox systems in U1285 human lung carcinoma cells.

Pycnogenol, which is extracted from the bark of French maritime pine, has been shown to have antioxidant and free radical scavenging activities. Thioredoxin reductase (TrxR), glutathione peroxidase (GPx) and glutathione reductase (GR) are three central redox enzymes that are active in endogenous defence against oxidative stress in the cell. Treatment of cells with Pycnogenol decreased the activity of both TrxR and GPx in cells by more than 50%, but GR was not affected. As previously reported, both enzymes were induced after treatment with hydrogen peroxide and selenite. The presence of Pycnogenol efficiently decreased selenite-mediated reactive oxygen species (ROS) production. Addition of Pycnogenol after selenite treatment reduced the mRNA expression and activity of TrxR to basal levels. In contrast, the GPx activity was completely unaffected. The discrepancy between TrxR and GPx regulation may indicate that transcription of TrxR is induced primarily by oxidative stress. As TrxR is induced in various pathological conditions, including tumours and inflammatory conditions, decreased activity mediated by a non-toxic agent such as Pycnogenol may be of great value.