Nucleoside dimers analogs containing floxuridine and thymidine with unnatural linker groups: synthesis and cancer line studies. Part III

Abstract

Two series of novel fluorinated nucleosides dimers with an unnatural 1,2,3-triazole linkage were synthesized. The obtained molecules were prepared using “click” chemistry approach based on copper(I) catalyzed Huisgen azide–alkyne cycloaddition. It was performed between 3′- and 5′-azido-nucleosides as the azide components, and the 3′-O- and 5′-O-propargyl-nucleosides as the alkyne components. Based on analysis of the ³ Brunton, L. L.; Lazo, J. S.; Parker, K. L. (Eds.), Goodman & Gilman’s the Pharmacological Basis of Therapeutics, 11th ed.; McGraw-Hill, Medical Publishing Division: New York, NY, 2006. [Google Scholar]J_HH, ³ Brunton, L. L.; Lazo, J. S.; Parker, K. L. (Eds.), Goodman & Gilman’s the Pharmacological Basis of Therapeutics, 11th ed.; McGraw-Hill, Medical Publishing Division: New York, NY, 2006. [Google Scholar]J_H1′C2 and ³ Brunton, L. L.; Lazo, J. S.; Parker, K. L. (Eds.), Goodman & Gilman’s the Pharmacological Basis of Therapeutics, 11th ed.; McGraw-Hill, Medical Publishing Division: New York, NY, 2006. [Google Scholar]J_H1′C6 we estimated conformational preferences of sugar part and orientation around glycosidic bond. All described nucleosides dimers analogs were characterized by spectroscopic methods and evaluated for their in vitro cytotoxicity in three human cancer cell lines: cervical (HeLa), oral (KB) and breast (MCF-7).     

Synthesis of an O-alkynyl-chitosan and its chemoselective conjugation with a PEG-like amino-azide through click chemistry

N-Phthaloyl-chitosan O-prop-2-ynyl carbamate was prepared as a biopolymer amenable to undergo chemoselective conjugation by azide-alkyne coupling, while allowing upturn of chitosan's amines after dephthaloylation. N-phthaloylchitosan was prepared according to previously described methods and, due to its low solubility in current organic media, subsequent modifications were run in heterogeneous conditions. Activation of hydroxyls with carbonyl-1,1′-diimidazole and coupling to propargylamine yielded N-phthaloyl-chitosan O-prop-2-ynyl carbamate, then coupled to a model PEG-like azide by azide-alkyne coupling, giving the expected triazolyl conjugate. N-Dephthaloylation allowed recovery of the free amines, responsible for chitosan's bioadhesion and tissue-regeneration properties.The structures of all polymers were confirmed by Fourier-transformed infra-red (FT-IR) and X-ray photoelectron (XPS) spectroscopies, as well as by solid-state nuclear magnetic resonance (SSNMR). All chitosan derivatives were poorly soluble in both aqueous and organic media, which makes them suitable for topical applications or for removal of toxic substances from either the gastric intestinal tract or environmental sources.     

Homology modeling and virtual screening of ubiquitin conjugation enzyme E2A for designing a novel selective antagonist against cancer

Abstract

Cancer is a major health problem in the world. The initiation and progression of cancer is due to imbalance between the programmed cell growth and death. These processes are triggered by the ubiquitin family enzymes. The ubiquitin-like proteins are responsible for the cell metabolism. Ubiquitin-dependent proteolysis by the 26s proteasome plays a crucial role in cell cycle progression as well as in tumorigenesis. In the ubiquitin proteasomal degradation pathway, ubiquitin conjugation enzyme E2A (UBE2A) binds with ubiquitin ligase RAD18, results in polyubiquitation reaction and cell cycle progression. UBE2A is an important contributing factor for the control of tumorigenesis. In the present work, the 3D model of the protein UBE2A was generated by homology modeling technique. The generated 3D structure of the UBE2A was validated, and active site was identified using standard computational protocols. The active site was subjected to structure-based virtual screening using small molecule data banks, and new molecules were identified. The ADME properties of the new ligand molecules were predicted, and the new ligands are identified as potent UBE2A antagonists for cancer therapy.     

Autophagy and chemotherapy resistance: a promising therapeutic target for cancer treatment

Induction of cell death and inhibition of cell survival are the main principles of cancer therapy. Resistance to chemotherapeutic agents is a major problem in oncology, which limits the effectiveness of anticancer drugs. A variety of factors contribute to drug resistance, including host factors, specific genetic or epigenetic alterations in the cancer cells and so on. Although various mechanisms by which cancer cells become resistant to anticancer drugs in the microenvironment have been well elucidated, how to circumvent this resistance to improve anticancer efficacy remains to be defined. Autophagy, an important homeostatic cellular recycling mechanism, is now emerging as a crucial player in response to metabolic and therapeutic stresses, which attempts to maintain/restore metabolic homeostasis through the catabolic lysis of excessive or unnecessary proteins and injured or aged organelles. Recently, several studies have shown that autophagy constitutes a potential target for cancer therapy and the induction of autophagy in response to therapeutics can be viewed as having a prodeath or a prosurvival role, which contributes to the anticancer efficacy of these drugs as well as drug resistance. Thus, understanding the novel function of autophagy may allow us to develop a promising therapeutic strategy to enhance the effects of chemotherapy and improve clinical outcomes in the treatment of cancer patients.     

Synthesis of variously coupled conjugates of d-glucose, 1,3,4-oxadiazole, and 1,2,3-triazole for inhibition of glycogen phosphorylase

5-(O-Perbenzoylated-β-d-glucopyranosyl)tetrazole was obtained from O-perbenzoylated-β-d-glucopyranosyl cyanide by Bu₃SnN₃ or Me₃SiN₃–Bu₂SnO. This tetrazole was transformed into 5-ethynyl- as well as 5-chloromethyl-2-(O-perbenzoylated-β-d-glucopyranosyl)-1,3,4-oxadiazoles by acylation with propiolic acid–DCC or chloroacetyl chloride, respectively. The chloromethyl oxadiazole gave the corresponding azidomethyl derivative on treatment with NaN₃. These compounds were reacted with several alkynes and azides under Cu(I) catalysed cycloaddition conditions to give, after removal of the protecting groups by the Zemplén protocol, β-d-glucopyranosyl-1,3,4-oxadiazolyl-1,2,3-triazole, β-d-glucopyranosyl-1,2,3-triazolyl-1,3,4-oxadiazole, and β-d-glucopyranosyl-1,3,4-oxadiazolylmethyl-1,2,3-triazole type compounds. 5-Phenyltetrazole was also transformed under the above conditions into a series of aryl-1,3,4-oxadiazolyl-1,2,3-triazoles, aryl-1,2,3-triazolyl-1,3,4-oxadiazoles, and aryl-1,3,4-oxadiazolylmethyl-1,2,3-triazoles. The new compounds were assayed against rabbit muscle glycogen phosphorylase b and the best inhibitors had inhibition constants in the upper micromolar range (2-phenyl-5-[1-(β-d-glucopyranosyl)-1,2,3-triazol-4-yl]-1,3,4-oxadiazole 36: K_i = 854 μM, 2-(β-d-glucopyranosyl)-5-[1-(naphthalen-2-yl)-1,2,3-triazol-4-yl]-1,3,4-oxadiazole 47: K_i = 745 μM).     

Hypofractionated radiation therapy for early breast cancer: Follow up of a new treatment standard

AimTo assess the oncological outcomes of patients with early breast cancer treated with breast-conserving surgery and adjuvant hypofractionated radiation therapy.Methods and MaterialThis retrospective analysis included all patients ≥50 year of age with T1-2 N0 M0 breast cancer treated at our Radiation Oncology Unit between 2008 and 2011. Whole-breast radiation therapy was delivered to a dose of 42.5 Gy in 16 fractions, without boost. The primary outcome was local control.Results212 patients were identified. With a median follow up of 60 months, we found 3% local recurrence and 5.3% regional and/or distant recurrences. At the moment of data analysis, 17 patients had died. Out of 5 local recurrences, 2 had previously had a distant recurrence, both of them died. The other three were still alive at the last follow up. These results are comparable to those observed in Phase III trials that use this fractionation scheme.ConclusionsThe results obtained with this retrospective analysis are comparable to those obtained in large randomized trials. This data also supports the use of hypofractionated radiation therapy in Latin America. Hypofractionated radiation therapy for early breast cancer patients should be the standard adjuvant treatment.     

IgE immunotherapy: A novel concept with promise for the treatment of cancer

The importance of antibodies in activating immune responses against tumors is now better appreciated with the emergence of checkpoint blockade antibodies and with engineered antibody Fc domains featuring enhanced capacity to focus potent effector cells against cancer cells. Antibodies designed with Fc regions of the IgE class can confer natural, potent, long-lived immune surveillance in tissues through tenacious engagement of high-affinity cognate Fc receptors on distinct, often tumor-resident immune effector cells, and through ability to activate these cells under tumor-induced Th2-biased conditions. Here, we review the properties that make IgE a contributor to the allergic response and a critical player in the protection against parasites, which also support IgE as a novel anti-cancer modality. We discuss IgE-based active and passive immunotherapeutic approaches in disparate in vitro and in vivo model systems, collectively suggesting the potential of IgE immunotherapies in oncology. Translation toward clinical application is now in progress.     

Nanoparticles and cancer therapy: Perspectives for application of nanoparticles in the treatment of cancers

Rapid growth in nanotechnology toward the development of nanomedicine agents holds massive promise to improve therapeutic approaches against cancer. Nanomedicine products represent an opportunity to achieve sophisticated targeting strategies and multifunctionality. Nowadays, nanoparticles (NPs) have multiple applications in different branches of science. In recent years, NPs have repetitively been reported to play a significant role in modern medicine. They have been analyzed for different clinical applications, such as drug carriers, gene delivery to tumors, and contrast agents in imaging. A wide range of nanomaterials based on organic, inorganic, lipid, or glycan compounds, as well as on synthetic polymers has been utilized for the development and improvement of new cancer therapeutics. In this study, we discuss the role of NPs in treating cancer among different drug delivery methods for cancer therapy.     

A novel dynamic field-matching technique for treatment of patients with para-aortic node-positive cervical cancer: Clinical experience

Aim

To report outcomes for patients with para-aortic lymph node positive cervical cancer treated with a dynamic field-matching technique.

Background

PET staging of cervical cancer has increased identification of patients with para-aortic lymph node metastasis. IMRT enables dose escalation in this area, but matching IMRT fields with traditional whole pelvis fields presents a challenge.

Materials and methods

From 2003 to 2012, 20 patients with cervical cancer and para-aortic lymph node metastasis were treated utilizing the dynamic field-matching technique. As opposed to single-isocenter half-beam junction techniques, this technique employs wedge-shaped dose junctions for the abutment of fields. We reviewed the records of all patients who completed treatment with the technique and abstracted treatment, toxicity, and disease-related outcome data for analysis.

Results

Median prescribed dose to the whole pelvis field was 45 Gy and para-aortic IMRT field 50.4 Gy. All but 3 patients underwent HDR (13 pts) or LDR (4 pts) brachytherapy. All patients developed lower GI toxicity; 10 grade 1, 9 grade 2, and 1 grade 4 (enterovaginal fistula). Median DFS was 12.4 months with 1 and 2-year DFS 60.0% and 38.1%. One-year OS was 83.7% and 2-year OS, 64.4%. A total of 10 patients developed recurrence; none occurred at the matched junction.

Conclusions

The dynamic field-matching technique provides a means for joining conventional whole pelvis fields and para-aortic IMRT fields that substantially reduces dose deviations at the junction due to field mismatch. Treatment with the dynamic matching technique is simple, effective, and tolerated with no apparent increase in toxicity.     

Search for novel histone deacetylase inhibitors. Part II: Design and synthesis of novel isoferulic acid derivatives

Previously, we described the discovery of potent ferulic acid-based histone deacetylase inhibitors (HDACIs) with halogeno-acetanilide as novel surface recognition moiety (SRM). In order to improve the affinity and activity of these HDACIs, twenty seven isoferulic acid derivatives were described herein. The majority of title compounds displayed potent HDAC inhibitory activity. In particular, IF5 and IF6 exhibited significant enzymatic inhibitory activities, with IC₅₀ values of 0.73 ± 0.08 and 0.57 ± 0.16 μM, respectively. Furthermore, these compounds showed moderate antiproliferative activity against human cancer cells. Especially, IF6 displayed promising profile as an antitumor candidate with IC₅₀ value of 3.91 ± 0.97 μM against HeLa cells. The results indicated that these isoferulic acid derivatives could serve as promising lead compounds for further optimization.     

Vector-based RNAi,a novel tool for isoform-specific knock-down of VEGF and anti-angiogenesis gene therapy of cancer

Vascular endothelial growth factor (VEGF) carries out multifaceted functions in tumor development, and it exists as at least five isoforms with distinct biologic activities and clinical implications. Several strategies have been developed to block VEGF for cancer therapy; however, the approach to target-specific VEGF isoform(s) has not been explored to date. In the present study, we show that DNA vector-based RNA interference (RNAi), in which RNAi sequences targeting murine VEGF isoforms are inserted downstream of an RNA polymerase III promoter, has potential applications in isoform-specific "knock-down" of VEGF. Large molecular weight VEGF isoforms were specifically reduced in vitro in the presence of isoform-specific RNAi constructs. Additionally, H1 promoter may be superior to U6 promoter when used for vector-based RNAi of VEGF isoforms. This strategy provides a novel tool to study the function of various VEGF isoforms and may contribute to VEGF isoform-specific treatment in cancer.     

Dual inhibition of BDNF/TrkB and autophagy: a promising therapeutic approach for colorectal cancer

Colorectal cancer (CRC) is the most common digestive cancer in the Western world. Despite effective therapies, resistance and/or recurrence frequently occur. The present study investigated the impact of two survival pathways—neurotrophic factors (TrkB/BDNF) and autophagy—on cell fate and tumour evolution. In vitro studies were performed on two CRC cell lines, SW480 (primary tumour) and SW620 (lymph node invasion), which were also used for subcutaneous xenografts on a nude mouse model. In addition, the presence of neurotrophic factors (NTs) and autophagy markers were assessed in tissue samples representative of different stages. On the basis of our previous study (which demonstrated that TrkB overexpression is associated with prosurvival signaling in CRC cells), we pharmacologically inhibited NTs pathways with K252a. As expected, an inactivation of the PI3K/AKT pathway was observed and CRC cells initiated autophagy. Conversely, blocking the autophagic flux with chloroquine or with ATG5‐siRNA overactivated TrkB/BDNF signaling. In vitro, dual inhibition improved the effectiveness of single treatment by significantly reducing metabolic activity and enhancing apoptotic cell death. These findings were accentuated in vivo, in which dual inhibition induced a spectacular reduction in tumour volume following long‐term treatment (21 days for K252a and 12 days for CQ). Finally, significant amounts of phospho‐TrkB and LC3II were found in the patients’ tissues, highlighting their relevance in CRC tumour biology. Taken together, our results show that targeting NTs and autophagy pathways potentially constitutes a new therapeutic approach for CRC.     

Combination of baloxavir and oseltamivir for treatment of severe influenza infection in hematopoietic cell transplant recipients: a novel treatment strategy for a high-risk population

Baloxavir, a cap-dependent endonuclease inhibitor, was recently approved for treatment of severe influenza infections. Combining baloxavir with oseltamivir has been proposed to increase the response rate. We report 2 hematopoietic cell transplant recipients with severe influenza infections who were treated with this combination and discuss possible reasons for their different responses.     

Synthesis and mass spectroscopy kinetics of a novel ternary copper(II) complex with cytotoxic activity against cancer cells

The X-ray structure of the [Cu(I-hip)(phen)2](+).(I-hip-).(H2O)7 complex (1) (where I-hipH is referred to o-iodohippuric acid and phen is 1,10-phenanthroline) and its binary synthetic intermediate [Cu(I-hip)2(H2O)3].(H2O)2 (2) have been solved and characterized by different techniques. This ternary [Cu(I-hip)(phen)2]+.(I-hip-).7H2O complex generates the copper(I) complex [Cu(phen)2]+ in aqueous solution without the addition of any external reductant, possibly by an intramolecular red-ox process in the presence of oxygen; the ESI-HRMS spectra (electrospray ionization-high resolution mass spectroscopy) detect these species and 24h after the solution, [Cu(phen)2]+ is the main product. The complex 1 is capable of cleaving DNA. To evaluate the biological properties, we carried out: cell culture, cell proliferation assays, cell cycle analysis, and electrophoresis (SDS-PAGE) and immunoblotting. Complex 1 induced apoptosis of A549 cells at low nanomolar and induced marked decreases of cancer cells at concentrations that did not change adipocyte survival. These data indicate that the parent complex is a potential anticancer drug.     

肝癌干细胞分子标志物和干性维持机制研究进展

原发性肝癌是一种发生在肝脏的侵袭性肿瘤,具有极易发生转移和复发的特点.原发性肝癌主要包括肝细胞癌、肝内胆管癌、混合肝细胞胆管癌和纤维板层型肝细胞癌等.目前,手术切除、放射性和化学治疗仍是肝癌治疗的主要手段,但其特异性差、临床效果有限,肝癌患者5年总生存率仅为18％.肝癌干细胞是存在于肝癌组织中特定的细胞亚群,具有自我更...     

Structural transition of kidney cystatin in dimethylnitrosamine-induced renal cancer in rats: identification as a novel biomarker for kidney cancer and prognosis

In our study, renal cancer is induced in rats making use of dimethylnitrosamine (DMN). G1 – Group 1 were control rats and G2 – Group 2 rats were given a single intra-peritoneal injection of DMN of 50 mg/kg body weight resulting in 100% incidences of renal tumors after 12 months. SEM and histopathology confirmed the presence of renal cancer in the DMN-treated rats. Making use of ammonium sulfate precipitation and gel filtration chromatography on Sephacryl S-100HR column, a thiol protease inhibitor was isolated from kidney of control rats known as Rat kidney Cystatin (RKC) as well as from kidney of cancerous rat called as Cancerous Rat Kidney Cystatin (CRKC). Both these inhibitors were characterized, and interestingly, it was found that CRKC showed greater anti-papain activity and also it was stable in a broad pH and temperature range thus implying that CRKC is more stable as compared to RKC. UV and fluorescence spectroscopy point out in structural difference between RKC and CRKC which was further confirmed by Circular dichroism (CD) and FTIR spectroscopy. Our study clearly showed that kidney cystatin is structurally modified in the case of renal cancer and performs its role in a more efficacious manner.     

A click chemistry approach to pleuromutilin derivatives. Part 3: Extended footprinting analysis and excellent MRSA inhibition for a derivative with an adenine phenyl side chain

Five promising pleuromutilin derivatives from our former studies, all containing adenine on various linkers, were supplemented with two new compounds. The binding to Escherichia coli ribosomes was verified by extensive chemical footprinting analysis. The ability to inhibit bacterial growth was investigated on two Staphylococcus aureus strains and compared to the pleuromutilin drugs tiamulin and valnemulin. Three of the compounds show an effect similar to tiamulin and one compound shows an excellent effect similar to valnemulin.