5-(4-Methoxybenzylidene)thiazolidine-2,4-dione-derived VEGFR-2 inhibitors: Design,synthesis, molecular docking,and anticancer evaluations

A novel series of 5-(4-methoxybenzylidene)thiazolidine-2,4-dione derivatives, 5a–g and 7a–f , was designed, synthesized, and evaluated for their anticancer activity against HepG2, HCT116, and MCF-7 cells. HepG2 and HCT116 were the most sensitive cell lines to the influence of the new derivatives. In particular, compounds 7f , 7e , 7d , and 7c were found to be the most potent derivatives of all the tested compounds against the HepG2, HCT116, and MCF-7 cancer cell lines. Compound 7f (IC₅₀ = 6.19 ± 0.5, 5.47 ± 0.3, and 7.26 ± 0.3 µM, respectively) exhibited a higher activity than sorafenib (IC₅₀ = 9.18 ± 0.6, 8.37 ± 0.7, and 5.10 ± 0.4 µM, respectively) against HepG2 and MCF-7, cells but a lower activity against HCT116 cancer cells, respectively. Also, this compound displayed a higher activity than doxorubicin (IC₅₀ = 7.94 ± 0.6, 8.07 ± 0.8, and 6.75 ± 0.4 µM, respectively) against HepG2 and MCF-7 cells, but nearly the same activity against HCT116 cells, respectively. All derivatives, 5a–g and 7a–f , were evaluated for their inhibitory activities against vascular endothelial growth factor receptor-2 (VEGFR-2). Among them, compound 7f was found to be the most potent derivative that inhibited VEGFR-2 at an IC₅₀ value of 0.12 ± 0.02 µM, which is nearly the same as that of sorafenib (IC₅₀ = 0.10 ± 0.02 µM). Compounds 7e , 7d , 7c , and 7b exhibited the highest activity, with IC₅₀ values of 0.13 ± 0.02, 0.14 ± 0.02, 0.14 ± 0.02, and 0.18 ± 0.03 µM, respectively, which are more than the half of that of sorafenib. Furthermore, molecular docking was performed to investigate their binding mode and affinities toward the VEGFR-2 receptor. The data obtained from the docking studies highly correlated with those obtained from the biological screening.     

Benzoxazole/benzothiazole‐derived VEGFR‐2 inhibitors: Design,synthesis, molecular docking,and anticancer evaluations

A novel series of benzoxazole/benzothiazole derivatives 4a–c – 11a–e were designed, synthesized, and evaluated for anticancer activity against HepG2, HCT‐116, and MCF‐7 cells. HCT‐116 was the most sensitive cell line to the influence of the new derivatives. In particular, compound 4c was found to be the most potent derivative against HepG2, HCT‐116, and MCF‐7 cells, with IC₅₀ values = 9.45 ± 0.8, 5.76 ± 0.4, and 7.36 ± 0.5 µM, respectively. Compounds 4b, 9f , and 9c showed the highest anticancer activities against HepG2 cells with IC₅₀ values of 9.97 ± 0.8, 9.99 ± 0.8, and 11.02 ± 1.0 µM, respectively, HCT‐116 cells with IC₅₀ values of 6.99 ± 0.5, 7.44 ± 0.4, and 8.15 ± 0.8 µM, respectively, and MCF‐7 cells with IC₅₀ values of 7.89 ± 0.7, 8.24 ± 0.7, and 9.32 ± 0.7 µM, respectively, in comparison with sorafenib as reference drug with IC₅₀ values of 9.18 ± 0.6, 5.47 ± 0.3, and 7.26 ± 0.3 µM, respectively. The most active compounds 4a–c, 9b,c,e,f,h , and 11c,e were further evaluated for their VEGFR‐2 inhibition. Compounds 4c and 4b potently inhibited VEGFR‐2 at IC₅₀ values of 0.12 ± 0.01 and 0.13 ± 0.02 µM, respectively, which are nearly equipotent to the sorafenib IC₅₀ value (0.10 ± 0.02 µM). Furthermore, molecular docking studies were performed for all synthesized compounds to assess their binding pattern and affinity toward the VEGFR‐2 active site.     

Design,synthesis, docking,and anticancer evaluations of phthalazines as VEGFR-2 inhibitors

Twenty new N-substituted-4-phenylphthalazin-1-amine derivatives were designed, synthesized, and evaluated for their anticancer activities against HepG2, HCT-116, and MCF-7 cells as VEGFR-2 inhibitors. HCT-116 was the most sensitive cell line to the influence of the new derivatives. In particular, compound 7f was found to be the most potent derivative among all the tested compounds against the three cancer cell lines, with 50% inhibition concentration, IC₅₀ = 3.97, 4.83, and 4.58 µM, respectively, which is more potent than both sorafenib (IC₅₀ = 9.18, 5.47, and 7.26 µM, respectively) and doxorubicin (IC₅₀ = 7.94, 8.07, and 6.75 µM, respectively). Fifteen of the synthesized derivatives were selected to evaluate their inhibitory activities against VEGFR-2. Compound 7f was found to be the most potent derivative that inhibited VEGFR-2 at an IC₅₀ value of 0.08 µM, which is more potent than sorafenib (IC₅₀ = 0.10 µM). Compound 8c inhibited VEGFR-2 at an IC₅₀ value of 0.10 µM, which is equipotent to sorafenib. Moreover, compound 7a showed very good activity with IC₅₀ values of 0.11 µM, which is nearly equipotent to sorafenib. In addition, compounds 7d , 7c , and 7g possessed very good VEGFR-2-inhibitory activity, with IC₅₀ values of 0.14, 0.17, and 0.23 µM, respectively.     

Design,synthesis, molecular docking,and anticancer activity of benzoxazole derivatives as VEGFR‐2 inhibitors

Novel series of benzoxazole s 4 _a‐f ‐16 were designed, synthesized, and evaluated for anticancer activity against HepG2, HCT‐116, and MCF‐7 cells. HCT‐116 was the most sensitive cell line to the influence of the new derivatives. In particular, compound 5 _e was found to be the most potent against HepG2, HCT‐116, and MCF‐7 with IC₅₀ = 4.13 ± 0.2, 6.93 ± 0.3, and 8.67 ± 0.5 µM, respectively. Compounds 5 _c , 5 _f , 6 _b , 5 _d , and 6 _c showed the highest anticancer activities against HepG2 cells with IC₅₀ of 5.93 ± 0.2, 6.58 ± 0.4, 8.10 ± 0.7, 8.75 ± 0.7, and 9.95 ± 0.9 µM, respectively; HCT‐116 cells with IC₅₀ of 7.14 ± 0.4, 9.10 ± 0.8, 7.91 ± 0.6, 9.52 ± 0.5, and 12.48 ± 1.1 µM, respectively; and MCF‐7 cells with IC₅₀ of 8.93 ± 0.6, 10.11 ± 0.9, 12.31 ± 1.0, 9.95 ± 0.8, and 15.70 ± 1.4 µM, respectively, compared with sorafenib as a reference drug with IC₅₀ of 9.18 ± 0.6, 5.47 ± 0.3, and 7.26 ± 0.3 µM, respectively. The most active compounds 5 _c‐f and 6 _b,c were further evaluated for their vascular endothelial growth factor receptor‐2 (VEGFR‐2) inhibition. Compounds 5 _e and 5 _c potently inhibited VEGFR‐2 at lower IC₅₀ values of 0.07 ± 0.01 and 0.08 ± 0.01 µM, respectively, compared with sorafenib (IC₅₀ = 0.1 ± 0.02 µM). Compound 5 _f potently inhibited VEGFR‐2 at low IC₅₀ value (0.10 ± 0.02 µM) equipotent to sorafenib. Our design was based on the essential pharmacophoric features of the VEGFR‐2 inhibitor sorafenib. Molecular docking was performed for all compounds to assess their binding pattern and affinity toward the VEGFR‐2 active site.     

Senolytic drugs in respiratory medicine: is it an appropriate therapeutic approach?

Introduction: Aging is the major risk factor for most of the chronic diseases. Cellular senescence is one of the main hallmarks of aging. A growing body of evidence implicates accelerated mechanisms of aging, including cellular senescence, in idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD) pathogenesis. Senolytics are pharmaceutical agents that eliminate senescent cells, thus blocking tissue degeneration and late life complications and allowing tissue regeneration.

Areas covered: The potential use of senolytic drugs in respiratory medicine is examined and discussed.

Expert opinion: The promising signal generated by preclinical studies supports proof-of-principle clinical studies with senolytic agents in the treatment of IPF, but this signal is not very strong, and furthermore, senolytic drugs could be detrimental in IPF patients. On the other hand, the preclinical evidence that these agents are able to influence the natural history of COPD is still lacking. COPD is a very heterogeneous lung disease presenting different (mixed) phenotypes. Given the difference in underlying pathology of these phenotypes, it can be envisaged that lung aging is more or differently involved in some of these phenotypes than others. Consequently, it will be difficult to determine which COPD patient will benefit from a treatment with senolytics.     

Action of SN 28049, a new DNA binding topoisomerase II-directed antitumour drug: comparison with doxorubicin and etoposide

Aim: We have examined the cellular action of SN 28049 (N-[2-(dimethylamino)ethyl]-2,6-dimethyl-1-oxo-1,2-dihydrobenzo[b]-1,6-naphthyridine-4-carboxamide), a DNA binding drug with curative activity against the Colon 38 transplantable murine carcinoma, on human tumour cells. Its action has been compared with that of two topoisomerase II-targetted drugs, etoposide and doxorubicin. Methods: The NZM3 melanoma and HCT116 colon carcinoma cell lines, each expressing wild-type p53, were cultured and responses were compared by flow cytometry, electrophoresis, microscopy, and growth of tumour xenografts. Results: Responses of NZM3 cells to all three drugs, as measured by histone H2AX γ-phosphorylation, induction of the p53 pathway and cell cycle arrest, were comparable and typical of those of topoisomerase II poisons. Xenografts of NZM3 cells responded to SN 28049 with a tumour growth delay of 16 days. In contrast, HCT116 cells had an attenuated DNA damage response to the drugs and SN 28049 had no in vivo activity, consistent with low topoisomerase II activity. However, SN 28049 inhibited HCT116 cell growth in vitro and activated the p53 pathway to induce a state with G₂/M-phase DNA content, low mitotic index and a high proportion of binucleate cells. Treated cells expressed cyclin E and the senescence marker β-galactosidase but showed low expression of cyclin B and survivin. In comparison, etoposide caused little p53 expression or cycle arrest, and doxorubicin had an intermediate effect. Conclusion: The action of SN 28049 in NZM3 cells is typical of a topoisomerase II poison, but the low topoisomerase IIα activity of HCT116 cells allowed the detection of a second antiproliferative action of SN 28049 in which cells undergo post-mitotic cycle arrest and induction of p53.     

Dihydroartemisinin accelerates c-MYC oncoprotein degradation and induces apoptosis in c-MYC-overexpressing tumor cells

Artemisinin and its derivatives (ARTs) are effective antimalarial drugs and also possess profound anticancer activity. However, the mechanism accounted for its distinctive activity in tumor cells remains unelucidated. We computed Pair wise Pearson correlation coefficients to identify genes that show significant correlation with ARTs activity in NCI-55 cell lines using data obtained from studies with HG-U133A Affymetrix chip. We found c-myc is one of the genes that showed the highest positive correlation coefficients among the probe sets analyzed (r = 0.585, P < 0.001). Dihydroartemisinin (DHA), the main active metabolite of ARTs, induced significant apoptosis in HL-60 and HCT116 cells that express high levels of c-MYC. Stable knockdown of c-myc abrogated DHA-induced apoptosis in HCT116 cells. Conversely, forced expression of c-myc in NIH3T3 cells sensitized these cells to DHA-induced apoptosis. Interestingly, DHA irreversibly down-regulated the protein level of c-MYC in DHA-sensitive HCT116 cells, which is consistent to persistent G1 phase arrest induced by DHA. Further studies demonstrated that DHA accelerated the degradation of c-MYC protein and this process was blocked by pretreatment with the proteasome inhibitor MG-132 or GSK 3β inhibitor LiCl in HCT116 cells. Taken together, ARTs might be useful in the treatment of c-MYC-overexpressing tumors. We also suggest that c-MYC may potentially be a biomarker candidate for prediction of the antitumor efficacies of ARTs.     

Glycidamide genotoxicity modulated by Caspases genes polymorphisms

Acrylamide (AA) is amongst acknowledged carcinogenic dietary factors. Its DNA-reactive metabolite is glycidamide (GA). The present study intended to correlate the role of key polymorphic genes of apoptosis (CASP7, CASP8, CASP9, CASP10, LTA and TNFRSF1B) with biomarkers of effect of DNA damage, namely the sister chromatid exchange assay (SCE) and the comet assay in whole blood cells exposed to GA. The aim was to assess as a proof of concept the role that pro-apoptotic effector proteins might have in the yields of genotoxic effects when those effector proteins are coded by polymorphic genes. Whole blood from a small group of volunteers was exposed to GA to assess DNA damage and the volunteers were genotyped for polymorphic genes related to apoptosis pathways. A relation between the induction of SCE and several variants of the polymorphism CASP8 rs1035142 G > T was observed. Also, a relation between the % tail DNA and the CASP10 I522L polymorphism was found. Furthermore, associations between % tail DNA and several SNP–SNP interactions of CASP8 and CASP10 were found. A possible correlation between DNA damage and the genetic susceptibility, bestowed by polymorphic genes in the apoptosis inducing pathways was verified.     

New benzimidazole acridine derivative induces human colon cancer cell apoptosis in vitro via the ROS-JNK signaling pathway

Aim:

To investigate the mechanisms underlying anticancer action of the benzimidazole acridine derivative N-{(1H-benzo[d]imidazol-2-yl)methyl}-2-butylacridin-9-amine(8m) against human colon cancer cells in vitro.

Methods:

Human colon cancer cell lines SW480 and HCT116 were incubated in the presence of 8m, and then the cell proliferation and apoptosis were measured. The expression of apoptotic/signaling genes and proteins was detected using RT-PCR and Western blotting. ROS generation and mitochondrial membrane depolarization were visualized with fluorescence microscopy.

Results:

8m dose-dependently suppressed the proliferation of SW480 and HCT116 cells with IC50 values of 6.77 and 3.33 μmol/L, respectively. 8m induced apoptosis of HCT116 cells, accompanied by down-regulation of Bcl-2, up-regulation of death receptor-5 (DR5), truncation of Bid, cleavage of PARP, and activation of caspases (including caspase-8 and caspase-9 as well as the downstream caspases-3 and caspase-7). Moreover, 8m selectively activated JNK and p38 without affecting ERK in HCT116 cells. Knockout of JNK1, but not p38, attenuated 8m-induced apoptosis. In addition, 8m induced ROS production and mitochondrial membrane depolarization in HCT116 cells. Pretreatment with the antioxidants N-acetyl cysteine or glutathione attenuated 8m-induced apoptosis and JNK activation in HCT116 cells.

Conclusion:

The new benzimidazole acridine derivative, 8m exerts anticancer activity against human colon cancer cells in vitro by inducing both intrinsic and extrinsic apoptosis pathways via the ROS-JNK1 pathway.     

Design,synthesis, molecular docking,and anticancer evaluations of 1-benzylquinazoline-2,4(1H,3H)-dione bearing different moieties as VEGFR-2 inhibitors

A novel series of 1-benzylquinazoline-2,4(1H,3H)-dione derivatives, 6a , b to 11a – e , was designed, synthesized, and evaluated for their anticancer activity against HepG2, HCT-116, and MCF-7 cells. Compounds 11b , 11e , and 11c were found to be the most potent derivatives of all tested compounds against the HepG2, HCT-116, and MCF-7 cancer cell lines, with GI₅₀ = 9.16 ± 0.8, 5.69 ± 0.4, 5.27 ± 0.2 µM, 9.32 ± 0.9, 6.37 ± 0.7, 5.67 ± 0.5 µM, and 9.39 ± 0.5, 6.87 ± 0.7, 5.80 ± 0.4 µM, respectively. These compounds exhibited nearly the same activity as sorafenib against HepG2 and HCT-116 cells and a higher activity against MCF-7 cells (GI₅₀ = 9.18 ± 0.6, 5.47 ± 0.3, and 7.26 ± 0.3 µM, respectively). Also, these compounds displayed a lower activity than doxorubicin against HepG2 cells and a higher activity against HCT-116 and MCF-7 cells (GI₅₀ = 7.94 ± 0.6, 8.07 ± 0.8, and 6.75 ± 0.4 µM, respectively). The most active antiproliferative derivatives, 6a , b , 8 , 9 , and 11a – e , were selected to evaluate their enzymatic inhibitory activity against VEGFR-2. Compounds 11b , 11e , and 11c potently inhibited VEGFR-2 at IC₅₀ values of 0.12 ± 0.02, 0.12 ± 0.02, and 0.13 ± 0.02 µM, respectively, which are nearly equipotent as sorafenib IC₅₀ value (0.10 ± 0.02 µM). Furthermore, molecular docking studies were performed for all synthesized compounds to assess their binding pattern and affinity toward the VEGFR-2 active site.     

Interaction of celecoxib with different anti-cancer drugs is antagonistic in breast but not in other cancer cells

Celecoxib, an inhibitor of cyclooxygenase-2, is being investigated for enhancement of chemotherapy efficacy in cancer clinical trials. This study investigates the ability of cyclooxygenase-2 inhibitors to sensitize cells from different origins to several chemotherapeutic agents. The effect of the drug's mechanism of action and sequence of administration are also investigated.The sensitivity, cell cycle, apoptosis and DNA damage of five different cancer cell lines (HeLa, HCT116, HepG2, MCF7 and U251) to 5-FU, cisplatin, doxorubicin and etoposide ± celecoxib following different incubation schedules were analyzed.We found antagonism between celecoxib and the four drugs in the breast cancer cells MCF7 following all incubation schedules and between celecoxib and doxorubicin in all cell lines except for two combinations in HCT116 cells. Celecoxib with the other three drugs in the remaining four cell lines resulted in variable interactions.Mechanistic investigations revealed that celecoxib exerts different molecular effects in different cells. In some lines, it abrogates the drug-induced G2/M arrest enhancing pre-mature entry into mitosis with damaged DNA thus increasing apoptosis and resulting in synergism. In other cells, it enhances drug-induced G2/M arrest allowing time to repair drug-induced DNA damage before entry into mitosis and decreasing cell death resulting in antagonism. In some synergistic combinations, celecoxib-induced abrogation of G2/M arrest was not associated with apoptosis but permanent arrest in G1 phase.These results, if confirmed in-vivo, indicate that celecoxib is not a suitable chemosensitizer for breast cancer or with doxorubicin for other cancers. Moreover, combination of celecoxib with other drugs should be tailored to the tumor type, drug and administration schedule.     

Oxidative stress-mediated mitochondrial apoptosis induced by the acaricide,fenpyroximate, on cultured human colon cancer HCT 116 cells

Fenpyroximate (FEN) is an acaricide that inhibits mitochondrial electron transport at the NADH-coenzyme Q oxidoreductase (complex I). The present study was designed to investigate the molecular mechanisms underling FEN toxicity on cultured human colon carcinoma cells (HCT116). Our data showed that FEN induced HCT116 cell mortality in a concentration dependent manner. FEN arrested cell cycle in G0/G1 phase and increased DNA damage as assessed by comet assay. Induction of apoptosis was confirmed in HCT116 cells exposed to FEN by AO-EB staining and Annexin V-FITC/PI double staining assay. Moreover, FEN induced a loss in mitochondrial membrane potential (MMP), increased p53 and Bax mRNA expression and decreased bcl2 mRNA level. An increase in caspase 9 and caspase 3 activities was also detected. All toghether, these data suggest that FEN induce apoptosis in HCT116 cells via mitochondrial pathway. To check the implication of oxidative stress in FEN-induced cell toxicity, we examined the oxidative stress statue in HCT116 cells exposed to FEN and we tested the effect of a powerful antioxidant, N-acetylcystein (NAC), on FEN-caused toxicity. It was observed that FEN enhanced ROS generation and MDA levels and disturbed SOD and CAT activities. Besides, cell treatment with NAC significantly protected cells from mortality, DNA damage, loss of MMP, and caspase 3 activity induced by FEN. To the best of our knowledge, this is the first study showing that FEN induced mitochondrial apoptosis via ROS generation and oxidative stress.     

Quercetin attenuates doxorubicin cardiotoxicity by modulating Bmi-1 expression

Background and Purpose

Doxorubicin-based chemotherapy induces cardiotoxicity, which limits its clinical application. We previously reported the protective effects of quercetin against doxorubicin-induced hepatotoxicity. In this study, we tested the effects of quercetin on the expression of Bmi-1, a protein regulating mitochondrial function and ROS generation, as a mechanism underlying quercetin-mediated protection against doxorubicin-induced cardiotoxicity.

Experimental Approach

Effects of quercetin on doxorubicin-induced cardiotoxicity was evaluated using H9c2 cardiomyocytes and C57BL/6 mice. Changes in apoptosis, mitochondrial function, oxidative stress and related signalling were evaluated in H9c2 cells. Cardiac function, serum enzyme activity and reactive oxygen species (ROS) generation were measured in mice after a single injection of doxorubicin with or without quercetin pre-treatment.

Key Results

In H9c2 cells, quercetin reduced doxorubicin-induced apoptosis, mitochondrial dysfunction, ROS generation and DNA double-strand breaks. The quercetin-mediated protection against doxorubicin toxicity was characterized by decreased expression of Bid, p53 and oxidase (p47 and Nox1) and by increased expression of Bcl-2 and Bmi-1. Bmi-1 siRNA abolished the protective effect of quercetin against doxorubicin-induced toxicity in H9c2 cells. Furthermore, quercetin protected mice from doxorubicin-induced cardiac dysfunction that was accompanied by reduced ROS levels and lipid peroxidation, but enhanced the expression of Bmi-1 and anti-oxidative superoxide dismutase.

Conclusions and Implications

Our results demonstrate that quercetin decreased doxorubicin-induced cardiotoxicity in vitro and in vivo by reducing oxidative stress by up-regulation of Bmi-1 expression. The findings presented in this study have potential applications in preventing doxorubicin-induced cardiomyopathy.     

Anticancer effects of seaweed compounds fucoxanthin and phloroglucinol,alone and in combination with 5-fluorouracil in colon cells

ABSTRACT

Colorectal cancer therapy with 5-fluorouracil (5-Fu) frequently become ineffective due to resistance to this drug; and thus other effective compounds are essential for therapy. It is well-known marine brown seaweeds contain antioxidant compounds the carotenoid fucoxanthin (Fx) and polyphenolic compound phloroglucinol (Ph) which exerted diverse biological activities including antioxidant and anticancer. The aim of this study was to determine the anticancer activities of Fx or Ph alone as well as combination of each chemical with 5-Fu on two human colorectal cancer cell lines (HCT116 and HT29), with comparison to responses in a normal colon cell line (CCD-18Co). Effects of these compounds on cell viability, induction of DNA damage, and cell death were evaluated using MTT assay, comet assay, nuclear condensation assay, and Western blot. 5-Fu decreased cell viability in a concentration-dependent manner in HCT116 and HT29 cells but was not cytotoxic in CCD-18Co cells. 5-Fu induced DNA damage in HCT116 cells with induction of cell death, while no marked effects on DNA damage and cell death were observed in HT29 cells. Fx or Ph alone also reduced cell viability in both cancer cell lines but no apparent cytotoxic effect in CCD-18Co cells, except for Fx at 50 and 100 µM. Diminished cell viability was accompanied by induction of DNA damage (by Fx) and induction of cell death (by Ph). In combination with 5-Fu, Fx at 10 µM (in HCT116 and HT29 cells), and Ph at 300 µM (in HT29 cells) enhanced the cytotoxic effect of 5-Fu; however, no marked cytotoxicity was noted in CCD-18Co cells. Since Fx and Ph alone reduced cancer cell line viability without an effect on normal cells and when in combination enhanced the cytotoxic effect of 5-Fu only in colon cancer cells, these compounds seem promising as anticancer agents.     

Thiourea and thioether derivatives of sorafenib: synthesis, crystal structure, and antiproliferative activity

A series of novel sorafenib derivatives containing diaryl thiourea and thioether, 9a–u, was designed and synthesized, and their antiproliferative activities against HCT116 and MDA-MB-231 cell lines were also evaluated and described. Most compounds exhibited potent antiproliferative activity against HCT116 cells with IC₅₀ = 1.8–80.4 μM. Compounds 9p, 9r, and 9s demonstrated competitive antiproliferative activities to sorafenib, against all two cancer cell lines. The structures of all the newly synthesized compounds were determined by ¹H NMR, ¹³C NMR, and HRMS, and compound 9n was characterized by single-crystal X-ray diffraction. Primary structure–activity relationships (SAR) have also been established.     

Functional in vitro model to examine cancer therapy cytotoxicity in maturing rat testis

Childhood cancer treatment can lead to infertility. Organ culture of early postnatal testicular tissue might provide a valuable approach to the study of acute testicular toxicity. The aim of the present study was to develop a functional in vitro organ culture method, in order to identify sensitive target cells to doxorubicin-induced cytotoxicity in immature rat testis during germ cell migration prior initiation of the first wave of spermatogenesis. Testicular tissue fragments from 5-day-old Sprague–Dawley rats were cultured in the absence or presence of doxorubicin (40 and 100 ng/ml) and morphology, apoptosis, proliferation and testosterone secretion was analyzed. Postnatal testicular development proceeded normally in control samples for 48 h in vitro. In these untreated culture conditions germ and Sertoli cell numbers and germ cell migration were comparable to in vivo. Germ cells were the primary, most sensitive targets for in vitro-induced doxorubicin (100 ng/ml) toxicity and their death was not associated with any morphological defects in the Sertoli cells. Organ culture which reduces the need of animal experimentation can be used to study the cytotoxic effects of doxorubicin on the immature testis.     

DZNep inhibits the proliferation of colon cancer HCT116 cells by inducing senescence and apoptosis

EZH2 is over-expressed in human colon cancer and is closely associated with tumor proliferation, metastasis and poor prognosis. Targeting and inhibiting EZH2 may be an effective therapeutic strategy for colon cancer. 3-Deazaneplanocin A (DZNep), as an EZH2 inhibitor, can suppress cancer cell growth. However, the anti-cancer role of DZNep in colon cancer cells has been rarely studied. In this study, we demonstrate that DZNep can inhibit the growth and survival of colon cancer HCT116 cells by inducing cellular senescence and apoptosis. The study provides a novel view of anti-cancer mechanisms of DZNep in human colon cancer cells.KEY WORDS: EZH2, Human colon cancer HCT116 cells, DZNep, Anti-cancer mechanisms     

Autophagy upregulation promotes survival and attenuates doxorubicin-induced cardiotoxicity

This study evaluated whether the manipulation of autophagy could attenuate the cardiotoxic effects of doxorubicin (DXR) in vitro as well as in a tumour-bearing mouse model of acute doxorubicin-induced cardiotoxicity. We examined the effect of an increase or inhibition of autophagy in combination with DXR on apoptosis, reactive oxygen species (ROS) production and mitochondrial function. H9C2 rat cardiac myoblasts were pre-treated with bafilomycin A1 (autophagy inhibitor, 10 nM) or rapamycin (autophagy inducer, 50 μM) followed by DXR treatment (3 μM). The augmentation of autophagy with rapamycin in the presence of DXR substantially ameliorated the detrimental effects induced by DXR. This combination treatment demonstrated improved cell viability, decreased apoptosis and ROS production and enhanced mitochondrial function. To corroborate these findings, GFP-LC3 mice were inoculated with a mouse breast cancer cell line (EO771). Following the appearance of tumours, animals were either treated with one injection of rapamycin (4 mg/kg) followed by two injections of DXR (10 mg/kg). Mice were then sacrificed and their hearts rapidly excised and utilized for biochemical and histological analyses. The combination treatment, rather than the combinants alone, conferred a cardioprotective effect. These hearts expressed down-regulation of the pro-apoptotic protein caspase-3 and cardiomyocyte cross-sectional area was preserved. These results strongly indicate that the co-treatment strategy with rapamycin can attenuate the cardiotoxic effects of DXR in a tumour-bearing mouse model.