RIP3 overexpression sensitizes human breast cancer cells to parthenolide in vitro via intracellular ROS accumulation

Aim： Receptor-interacting protein 3 （RIP3） is involved in tumor necrosis factor receptor signaling, and results in NF-KB-mediated prosurvival signaling and programmed cell death. The aim of this study was to determine whether overexpression of the RIP3 gene could sensitize human breast cancer cells to parthenolide in vitro. Methods： The expression of RIP3 mRNA in human breast cancer cell lines （MCF-7, MDA-MB-231, MDA-MB-435 and T47D） was detected using RT-PCR. Both MDA-MB-231 and MCF-7 cells were transfected with RIP3 expression or blank vectors via lentivirus. Cell viability was measured with MTT assay; intracellular ROS level and cell apoptosis were analyzed using flow cytometry. Results： RIP3 mRNA expression was not detected in the four human breast cancer cell lines tested. However, the transfection induced higher levels of RIP3 protein in MCF-7 and MDA-MB-231 cells. Furthermore, overexpression of RIP3 decreased the IC50 values of parthenolide from 17.6 to 12.6 μmol/L in MCF-7 cells, and from 16.6 to 9.9 μmol/L in MDA-MB-231 cells. Moreover, overexpression of RIP3 significantly increased parthenolide-induced apoptosis and ROS accumulation in MCF-7 and MDA-MB-231 cells. Pretreatment with N-acetyl-cysteine abrogated the increased sensitivity of RIP3-transfected MCF-7 and MDA-MB-231 cells to parthenolide. Conclusion： Overexpression of RIP3 sensitizes MCF-7 and MDA-MB-231 breast cancer cells to parthenolide in vitro via intracellular ROS accumulation.     

Bigelovin inhibits STAT3 signaling by inactivating JAK2 and induces apoptosis in human cancer cells

Aim:

To study the function and mechanism of bigelovin, a sesquiterpene lactone from the flower of Chinese herb Inula hupehensis, in regulating JAK2/STAT3 signaling and cancer cell growth.

Methods:

HepG2 cells stably transfected with the STAT3-responsive firefly luciferase reporter plasmid (HepG2/STAT3 cells), and a panel of human cancer cell lines were used to identify active compounds. Cell viability was measured using MTT assay. Western blotting was used to detect protein expression and phosphorylation. Kinase assays were performed and the reaction between bigelovin and thiol-containing compounds was analyzed with LC-MS.

Results:

Bigelovin (1–50 μmol/L) dose-dependently inhibited the IL-6-induced STAT3 activation in HepG2/STAT3 cells (IC₅₀=3.37 μmol/L) and the constitutive STAT3 activation in A549 and MDA-MB-468 cells. Furthermore, bigelovin dose-dependently inhibited JAK2 phosphorylation in HeLa and MDA-MB-468 cells, as well as the enzymatic activity of JAK2 in vitro (IC₅₀=44.24 μmol/L). Pretreatment of the cells with DTT (500 μmol/L) or GSH (500 μmol/L) eliminated the inhibitory effects of bigelovin on the IL-6-induced and the constitutive STAT3 activation. The results in LC-MS analysis suggested that bigelovin might react with cysteine residues of JAK2 leading to inactivation of JAK2. Bigelovin (5 and 20 μmol/L) had no effects on the signaling pathways of growth factors EGF, PDGF or insulin. Finally, bigelovin suppressed the cell viability and induced apoptosis in 10 different human cancer cell lines, particularly those with constitutively activated STAT3.

Conclusion:

Bigelovin potently inhibits STAT3 signaling by inactivating JAK2, and induces apoptosis of a variety of human cancer cells in vitro.     

Synthesis and cytotoxic properties of novel (E)-3-benzylidene-7-methoxychroman-4-one derivatives

Background and the purpose of the study

There has been increscent interest in the field of cancer chemotherapy by discovery and development of novel agents with high efficacy, low toxicity, and minimum side effects. In order to find new anticancer agents, we replaced the pyrazolone part of well-known cytotoxic agent SJ-172550 with 7-methoxychroman-4-one. Thus, a novel series of 3-benzylidene-4-chromanones were synthesized and tested in vitro against human cancer cell lines.

Methods

The title compounds were prepared by condensation of 7-methoxychroman-4-one with suitable aldehydes in appropriate alcohol in the presence of gaseous HCl. The antiproliferative activity of target compounds were evaluated against MDA-MB-231 (breast cancer), KB (nasopharyngeal epidermoid carcinoma) and SK-N-MC (human neuroblastoma) cell lines using MTT assay.

Results

Although the direct analog of SJ-172550 (compound 5d) did not show any cytotoxic activity against tested cell lines, but 2-(2-chloro-6-methoxyphenoxy)acetic acid methyl ester analog 5c showed some activity against MDA-MB-231 and SK-N-MC cells. Further modification of compound 5c resulted in the 3-chloro-4,5-dimethoxybenzylidene derivative 5b which demonstrated better cytotoxic profile against all tested cell lines (IC₅₀ values = 7.56–25.04 μg/ml).

Conclusion

The results demonstrated that the cytotoxic activity of compound 5b against MDA-MB-231 and SK-N-MC cells is more than etoposide. Therefore, compound 5b prototype could be considered as novel cytotoxic agent for further developing new anticancer chemotherapeutics.     

The epoxyeicosatrienoic acid-stimulated phosphorylation of EGF-R involves the activation of metalloproteinases and the release of HB-EGF in cancer cells

Aim:

To test the hypothesis that the epoxyeicosatrienoic acid (EET)-induced transactivation of EGF-R depends on the activation of metalloproteinases and the subsequent release of HB-EGF in cancer cells.

Methods:

Exogenous 14,15-EET were added to four human-derived cancer cell lines Tca-8113, A549, HepG2, and MDA-MB-231, or these same cell lines were transfected with a mutant CYP epoxygenase (CYP102 F87V, an active 14,15-epoxygenase). The effects of elevated EET levels on the phosphorylation of tyrosine residues in the EGF receptor and on ERK1/2 activation were then assessed.

Results:

Both the addition of 14,15-EET and the transfection of cells with CYP102 F87V markedly increased the phosphorylation of the tyrosine residues of EGF-R and ERK1/2, an effect that was blocked by a selective EGF-R tyrosine kinase inhibitor (tyrphostin AG1478), a broad-spectrum metalloproteinase inhibitor (1,10-phenanthroline), and an inhibitor of HB-EGF release (CRM197) in Tca-8113 cells. In addition, AG1478, 1,10-phenanthroline, and CRM197 also inhibited the tyrosine phosphorylation of EGF-R and ERK1/2 that was induced by 14,15-EET in the A549, HepG2, and MDA-MB-231 cell lines.

Conclusion:

These results suggest that the EET-induced transactivation of EGF-R depends on activation of metalloproteinases and the subsequent release of HB-EGF in cancer cell lines.     

Evaluation of Cassia occidentalis for in vitro cytotoxicity against human cancer cell lines and antibacterial activity

Objective:

To evaluate the in vitro cytotoxicity and antibacterial properties of Cassia occidentalis (whole plant) via alcoholic, hydro-alcoholic, and aqueous extracts against eight human cancer cell lines from six different tissues and four bacterial strains.

Material and Methods:

in vitro cytotoxicity against the human cancer cells, cultured for 48h in presence of different concentrations C. occidentalis extracts and percentage of cell viability, was evaluated using the sulforhodamine-B (SRB) assay. The antibacterial activity was performed using the standard protocol against bacterial strains.

Results:

It was observed that aqueous extract of C. occidentalis (whole plant) had more potential than hydro-alcoholic and alcoholic extracts against HCT-15, SW-620, PC-3, MCF-7, SiHa, and OVCAR-5 human cancer cell lines at 100, 30, and 10 μg/ml in a dose-dependent manner. The hydro-alcoholic extract showed potential against Bacillus subtillis.

Conclusion:

The plant can be explored for the possible development of lead molecules for drug discovery.     

Monitoring of incidence, severity, and causality of adverse drug reactions in hospitalized patients with cardiovascular disease

Background:

Patients admitted to cardiology department are mostly on polypharmacy. So drug-drug interactions and adverse effects of drugs are quite common. Yet, there is a paucity of data regarding adverse drug reaction (ADR) monitoring in cardiology department in India. The present study is an effort to fill up these lacunae.

Materials and Methods:

A prospective, observational study registering 966 indoor cardiology patients according to predetermined inclusion and exclusion criteria was conducted for one year. ADR profile was noted by spontaneous reporting and intensive monitoring. Naranjo ADR probability scale was used to establish the causality.

Results:

A total of 208 ADRs were reported from 188 patients (19.5%). Of these 188 patients, 62 patients (33%) were hospitalized primarily due to the development of ADRs, while 126 (67%) patients developed ADRs during hospital stay. Nitrates were the most common offender drug group (17.8%).

Conclusion:

Development of ADR in one of every five cardiac patient points toward a grave situation, but a higher incidence of Type A reactions in cardiology department means that these can be avoided.     

Myosin light chain kinase is responsible for high proliferative ability of breast cancer cells via antiapoptosis involving p38 pathway

Aim:

To investigate whether myosin light chain kinase (MLCK) contributed to the high proliferative ability of breast cancer cells.

Methods:

Soft agar colony formation on the MCF-7 and LM-MCF-7 cell lines was determined. The cell cycles of MCF-7 and LM-MCF-7 were detected using flow cytometry analysis. Western blot analysis was performed to detect the expression levels of p-ERK1/2, total-ERK1/2, p-p38, total p38, p-JNK, total-JNK, survivin, Bcl-2, p-MLC, caspase-9, cleaved caspase-9, and MLCK. After treatment with adriamycin (ADR), ML-7 and SB203580, apoptosis was examined using flow cytometry analysis and Annexin V-FITC fluorescence microscopy.

Results:

The breast cancer LM-MCF-7 cell line with high metastasis potential (a metastitic sub-clone of MCF-7) had higher anti-apoptosis ability relative to MCF-7 cells in response to adriamycin treatment (apoptosis rate: 6.76% vs 28.58%, P<0.05). Moreover, the expression level of MLCK was upregulated and the level of phosphorylated p38 (p-p38) was decreased in LM-MCF-7 cells. Flow cytometry analysis showed that ML-7, selective inhibitor of MLCK, could induce apoptosis of the LM-MCF-7 cells, in which the level of p-p38 was increased. Meanwhile, the expression levels of Bcl-2 and survivin were downregulated, while the caspase-9 was upregulated suggesting that the cells were undergone apoptosis. Flow cytometry analysis showed that SB203580, an inhibitor of p38, abolished ML-7-induced apoptosis, which resulted in the upregualtion of Bcl-2 and survivin, and downregulation of caspase-9, suggesting that Bcl-2, survivin and caspase-9 are downstream effectors of p38.

Conclusion:

MLCK is responsible for high proliferative ability of breast cancer cells through anti-apoptosis, in which p38 pathway was involved.     

Design,synthesis, docking study and cytotoxic activity evaluation of some novel letrozole analogs

Background

Breast cancer is the most common type of female cancer. One class of hormonal therapy for breast cancer drugs -non steroidal aromatase inhibitors- are triazole analogues. In this work, some derivatives of these drugs was designed and synthesized. All synthesized compounds were evaluated for their cytotoxic activities on breast cancer cell lines (MDA-MB-231, T47D and MCF-7).

Methods

Our synthetic route for designed compounds started from 4-bromotolunitrile which was reacted with 1H-1,2,4-triazole to afford 4-(4-cyanobenzyl)-1,2,4-triazole. The reaction of later compound with aromatic aldehydes led to formation of the designed compounds. Eleven novel derivatives 1a-k were tested for their cytotoxic activities on three human breast cancer cell lines.

Results

Among the synthesized compound, 4-[2-(3-chlorophenyl)-1-(1H-1,2,4-triazol-1-yl)ethenyl]benzonitrile (1c) showed the highest activity against MCF-7 and MDA-MB-231 cell lines and 4-[2-(4-methoxyphenyl)-1-(1H-1,2,4-triazol-1-yl)ethenyl]benzonitrile (1 h) exhibited highest activity against T47D cell line. According to cytotoxic activities results, compound 4-[2-(4-dimethylamino)-1-(1H-1,2,4-triazol-1-yl)ethenyl]benzonitrile (1 k) showed comparative activity against T47D and MDA-MB-231 cell lines with compound (1 h) and our reference drug Etoposide.

Conclusion

In the process of anti-cancer drug discovery, to find new potential anti-breast cancer agents, we designed and synthesized a novel series of letrozole analogs. Cytotoxicity evaluation revealed that compounds (1c) and (1 k) were the most potent compounds with comparative activity with Etoposide. The results revealed that π-π interactions are responsible for the enzyme inhibitions of compounds (1 c) and (1 k).Keyword: Breast cancer, Non-steroidal aromatase inhibitor, Cytotoxic activity     

A prospective, observational cohort study to elicit adverse effects of antiretroviral agents in a remote resource-restricted tribal population of Chhattisgarh

Objective:

To assess the adverse effects of antiretroviral therapy (HAART) and its adherence in HIV-infected patients, in remote and tribal area with restricted resources.

Materials and Methods:

This was a prospective, observational study carried out at Department of Medicine, Government Medical College, Jagdalpur. A set of questions were asked and adverse drug reactions (ADRs) were recorded for every patient.

Results:

79 HIV positive patients were analyzed. Among them, 68 (86%) had at least one ADR. The mean ADR per patient was 1.64 (±1.09). The most common ADR in our study was peripheral neuropathy (20.83%), followed by skin rashes (15.83%). Twenty-one patients (26.58%) had severe (grade-3 and grade-4) ADRs. Female patients had more ADRs (45.71%) than males (11.36%); severe ADRs had a statistically significant positive correlation with sex and CD4 cell count of the patients.

Conclusion:

In spite of high ADRs, HAART is the only answer to HIV/AIDS; thus, management requires a highly precise balance between benefits of durable HIV suppression and the risks of drug toxicity to achieve the therapeutic goals, with conventional drugs or with newer less toxic agents.     

Adverse Drug Reactions (ADR) in the inPatients of Medicine Department of a Rural Tertiary Care Teaching Hospital and Influence of Pharmacovigilance in Reporting ADR

Objectives:

(i) To find the incidence and study various aspects of Adverse Drug Reactions (ADR) in the inpatients of medicine department of Shree Krishna Hospital, a rural tertiary care teaching hospital. (ii) To test the impact of pharmacovigilance in reporting ADR.

Material & Methods:

A prospective study involving 600 patients admitted to the medical wards and TB & Chest diseases ward over a period of six months and a retrospective analysis of 600 case files for the corresponding period of the previous year were carried out to find the incidence rate of ADR, study various aspects of ADR like causality assessment, drugs frequently causing ADR etc. Suitably structured and pre-tested format was used for compiling the data.

Results:

In the prospective study, 18 of the 600 patients (3%) developed ADR. A significant number (77.78%) of patients developed ADR between the 3^rd and 10^th days of administering the drug/s. As the number of drugs increased, the incidence of ADR also increased. Majority of ADR (72.22%) occurred due to chemotherapeutic agents. 66.67% of ADR involved the gastrointestinal tract. None of the ADR was fatal. Sex of the patients did not influence the incidence rate of ADR. On the other hand, in the retrospective analysis, only ADR were reported in just 6 out of 600 patients (1%).

Conclusion:

The incidence rate of ADR is found to be much lower (3%) than the reported rate (10%-20%). Pharmacovigilance certainly contributes to picking up ADR.     

Establishment and characterization of primary lung cancer cell lines from Chinese population

Aim:

To establish and characterize primary lung cancer cell lines from Chinese population.

Methods:

Lung cancer specimens or pleural effusions were collected from Chinese lung cancer patients and cultured in vitro with ACL4 medium (for non-small cell lung carcinomas (NSCLC)) or HITES medium (for small cell lung carcinomas (SCLC)) supplemented with 5% FBS. All cell lines were maintained in culture for more than 25 passages. Most of these cell lines were further analyzed for oncogenic mutations, karyotype, cell growth kinetics, and tumorigenicity in nude mice.

Results:

Eight primary cell lines from Chinese lung cancer patients were established and characterized, including seven NSCLC cell lines and one SCLC cell line. Five NSCLC cell lines were found to harbor epidermal growth factor receptor (EGFR) kinase domain mutations.

Conclusion:

These well-characterized primary lung cancer cell lines from Chinese population provide a unique platform for future studies of the ethnic differences in lung cancer biology and drug response.     

A prospective study of adverse drug reactions to artemisinin-based combination therapy in a tertiary care hospital in India

Objectives:

Antimalarial drugs are commonly prescribed for the treatment of malaria and suspected cases of malaria in India. The recent trend is to prescribe ACT and the incidence of adverse reactions to this therapy is notwell-documented in Indian population. Therefore, this study was designed to assess ADR pattern of antimalarial drugs particularly ACT in India.

Materials and Methods:

Over a period of 1 year, 500 patients who were administered antimalarial drugs were enrolled in the study. The World Health Organization causality assessment scale was used for classifying the ADR.

Results:

In this study out of 500 patients, 251 complained of ADRs. The sex-wise difference in reporting of ADRs was statistically not significant (P=0.0943). The most common ADRs reported were nausea, anorexia and vomiting. ADRs were most commonly reported when chloroquine was coprescribed.

Conclusions:

This study indicates that ACT was commonlyused in the treatment of malaria. Results of the analysis suggest that all the ADRs were of moderate intensity and no serious ADR was observed. This baseline information will be useful to implement the ACT in India.KEY WORDS: Adverse drug reaction, antimalarial drugs, artemisinin, artemisinin-based combination therapy     

SZ-685C,a marine anthraquinone,is a potent inducer of apoptosis with anticancer activity by suppression of the Akt/FOXO pathway

Background and purpose:

The aims of this study were to investigate the anti-cancer activity of SZ-685C, an anthracycline analogue isolated from marine-derived mangrove endophytic fungi, and to explore the molecular mechanisms underlying such activity.

Experimental approach:

The effect of SZ-685C on the viability of cancer cell lines was investigated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. SZ-685C-induced apoptosis was assessed by Annexin V-fluorescein isothiocyanate/propidium iodide staining, terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling assay and analysis of caspase activation. The effect of SZ-685C on the Akt/FOXO pathway was studied using Western blotting analysis, and the in vivo anti-tumour efficacy was examined in an MDA-MB-435 breast cancer xenograft model.

Key results:

SZ-685C suppressed the proliferation of six cancer cell lines derived from human breast cancer, prostate cancer, glioma and hepatoma (IC₅₀ values ranged from 3.0 to 9.6 µM) and the growth of breast cancer xenografts in mice. SZ-685C had a direct apoptosis-inducing effect through both the extrinsic and intrinsic apoptotic pathways, as shown by activation of caspase-8 and 9 as well as effector caspase-3 and poly (ADP-ribose) polymerase. Phosphorylation of Akt and its downstream effectors, forkhead box protein O1 and forkhead box protein O3a, was down-regulated in SZ-685C-treated cancer cells. Furthermore, the pro-apoptotic protein Bim was up-regulated by SZ-685C treatment consistent with FOXO dephosphorylation.

Conclusions and implications:

SZ-685C could induce apoptosis through the Akt/FOXO pathway, which consequently leads to the observed anti-tumour effect both in vitro and in vivo. Our data suggest that SZ-685C may be a potentially promising Akt inhibitor and anti-cancer drug candidate.     

Synthesis and cytotoxic evaluation of some new[1,3]dioxolo[4,5-g]chromen-8-one derivatives

Background

Homoisoflavonoids are naturally occurring compounds belong to flavonoid classes possessing various biological properties such as cytotoxicity. In this work, an efficient strategy for the synthesis of novel homoisoflavonoids, [1,3]dioxolo[4,5-g]chromen-8-ones, was developed and all compounds were evaluated for their cytotoxic activities on three breast cancer cell lines.

Methods

Our synthetic route started from benzo[d][1,3]dioxol-5-ol which was reacted with 3-bromopropanoic acid followed by the reaction of oxalyl chloride to afford 6,7-dihydro-8H-[1,3]dioxolo[4,5-g]chromen-8-one. The aldol condensation of the later compound with aromatic aldehydes led to the formation of the title compounds. Five novel derivatives 4a-e were tested for their cytotoxic activity against three human breast cancer cell lines including MCF-7, T47D, and MDA-MB-231 using the MTT assay.

Results

Among the synthesized compounds, 7-benzylidene-6,7-dihydro-8H-[1,3]dioxolo[4,5-g]chromen-8-one (4a) exhibited the highest activity against three cell lines. Also the analysis of acridine orange/ethidium bromide staining results revealed that 7-benzylidene-6,7-dihydro-8H-[1,3]dioxolo[4,5-g]chromen-8-one (4a) and 7-(2-methoxybenzylidene)-6,7-dihydro-8H-[1,3]dioxolo[4,5-g]chromen-8-one (4b) induced apoptosis in T47D cell line.

Conclusion

Finally, the effect of methoxy group on the cytotoxicity of compounds 4b-4d was investigated in and it was revealed that it did not improve the activity of [1,3]dioxolo[4,5-g]chromen-8-ones against MCF-7, T47D, and MDA-MB-231.     

A novel sulfonamide agent,MPSP-001, exhibits potent activity against human cancer cells in vitro through disruption of microtubule

Aim:

To evaluate the anti-cancer effects of a new sulfonamide derivative, 2-(N-(3-chlorophenyl)-4-methoxyphenylsulfonamido)-N-hydroxypropanamide (MPSP-001).

Methods:

Human cancer cell lines (HepG2, THP-1, K562, HGC-27, SKOV3, PANC-1, SW480, Kba, HeLa, A549, MDA-MB-453, and MCF-7) were examined. The cytotoxicity of MPSP-001 was evaluated using the WST-8 assay. Cell cycle distribution was examined with flow cytometry. Mitotic spindle formation was detected using immunofluorescence microscopy. Apoptosis-related proteins were examined with Western blot using specific phosphorylated protein antibodies. Competitive tubulin-binding assay was performed to test whether the compound competitively bound to the colchicine site. Molecular docking was performed to explore the possible binding conformation.

Results:

MPSP-001 potently inhibited the growth of the 12 different types of human cancer cells with the IC₅₀ values ranging from 1.9 to 15.7 μmol/L. The compound exerted potent inhibition on the drug-resistant Kb/VCR and MCF-7/ADR cells, as on Kba and MCF-7 cells. In HeLa, HGC-27, A549, and other cells, the compound (5 μmol/L) caused cell cycle arrest at the G₂/M phase, and subsequently induced cell apoptosis. In Hela cells, it prevented the mitotic spindle formation. Furthermore, the compound dose-dependently inhibited polymerization of tubulin in vitro, and directly bound to the colchicine-site of β-tubulin. Molecular docking predicted that the compound may form two hydrogen bonds to the binding pocket. The compound showed synergistic effects with colchicine and taxol in blocking mitosis of HeLa cells.

Conclusion:

MPSP-001 shows a broad-spectrum of anti-tumor efficacy in vitro and represents a novel structure with anti-microtubule activity.     

Plumbagin attenuates cancer cell growth and osteoclast formation in the bone microenvironment of mice

Aim： To investigate the effects of plumbagin, a naphthoquinone derived from the medicinal plant Plumbago zeylanica, on human breast cancer cell growth and the cancer cell-induced osteolysis in the bone microenvironment of mice.
Methods： Human breast cancer cell subline MDA-MB-231SA with the ability to spread and grow in the bone was tested. The cell proliferation was determined using the CCK-8 assay. Apoptosis was detected with Annexin V/PI double-labeled flow cytometry. Red fluorescent protein-labeled MDA-MB-231SArfp cells were injected into the right tibia of female BALB/c-nu/nu mice. Three days after the inoculation, the mice were injected with plumbagin （2, 4, or 6 mg/kg, ip） 5 times per week for 7 weeks. The growth of the tumor cells was monitored using an in vivo imaging system. After the mice were sacrificed, the hind limbs were removed for radiographic and histological analyses.

Results： Plumbagin （2.5–20 μmol/L） concentration-dependently inhibited the cell viability and induced apoptosis of MDA-MB-231SA cells in vitro （the IC50 value of inhibition of cell viability was 14.7 μmol/L）. Administration of plumbagin to breast cancer bearing mice delayed the tumor growth by 2–3 weeks and reduced the tumor volume by 44%–74%. The in vivo imaging study showed that plumbagin dose-dependently inhibited MDA-MB-231SArfp cell growth in bone microenvironment. Furthermore, X-ray images and micro-CT study demonstrated that plumbagin reduced bone erosion area and prevented a decrease in bone tissue volume. Histological studies showed that plumbagin dose-dependently inhibited the breast cancer cell growth, enhanced the cell apoptosis and reduced the number of TRAcP-positive osteoclasts.

Conclusion： Plumbagin inhibits the cell growth and induces apoptosis in human breast cancer cells in mice bone microenvironment, leading to significant reduction in osteolytic lesions caused by the tumor cells.     

A role for L-��-lysophosphatidylinositol and GPR55 in the modulation of migration, orientation and polarization of human breast cancer cells

Background and purpose:

Increased circulating levels of L-α-lysophosphatidylinositol (LPI) are associated with cancer and LPI is a potent, ligand for the G-protein-coupled receptor GPR55. Here we have assessed the modulation of breast cancer cell migration, orientation and polarization by LPI and GPR55.

Experimental approach:

Quantitative RT-PCR was used to measure GPR55 expression in breast cancer cell lines. Cell migration and invasion were measured using a Boyden chamber chemotaxis assay and Cultrex® invasion assay, respectively. Cell polarization and orientation in response to the microenvironment were measured using slides containing nanometric grooves.

Key results:

GPR55 expression was detected in the highly metastatic MDA-MB-231 breast cancer cell line. In these cells, LPI stimulated binding of [³⁵S]GTPγS to cell membranes (pEC₅₀ 6.47 ± 0.45) and significantly enhanced cell chemotaxis towards serum. MCF-7 cells expressed low levels of GPR55 and did not migrate or invade towards serum factors. When GPR55 was over-expressed in MCF-7 cells, serum induced a robust migratory and invasive response, which was further enhanced by LPI and prevented by siRNA to GPR55. The physical microenvironment has been identified as a key factor in determining breast tumour cell metastatic fate. LPI endowed MDA-MB-231 cells with the capacity to detect shallow (40 nm deep) grooved slides and induced marked cancer cell polarization on both flat and grooved surfaces.

Conclusions and implications:

LPI and GPR55 play a role in the modulation of migration, orientation and polarization of breast cancer cells in response to the tumour microenvironment.This article is part of a themed issue on Cannabinoids. To view the editorial for this themed issue visit http://dx.doi.org/10.1111/j.1476-5381.2010.00831.x     

Regulation of angiotensin-(1-7) and angiotensin II type 1 receptor by telmisartan and losartan in adriamycin-induced rat heart failure

Aim:

To investigate the possible effects of telmisartan and losartan on cardiac function in adriamycin (ADR)-induced heart failure in rats, and to explore the changes in plasma level of angiotensin-(1–7)[Ang-(1–7)] and myocardial expression of angiotensin II type 1/2 receptors (AT1R / AT2R) and Mas receptor caused by the two drugs.

Methods:

Male Sprague-Dawley rats were randomly divided into 4 groups: the control group, ADR-treated heart failure group (ADR-HF), telmisartan plus ADR-treated group (Tel+ADR) and losartan plus ADR-treated group (Los+ADR). ADR was administrated (2.5 mg/kg, ip, 6 times in 2 weeks). The rats in the Tel+ADR and Los+ADR groups were treated orally with telmisartan (10 mg/kg daily po) and losartan (30 mg/kg daily), respectively, for 6 weeks. The plasma level of Ang-(1–7) was determined using ELISA. The mRNA and protein expression of myocardial Mas receptor, AT₁R and AT₂R were measured using RT-PCR and Western blotting, respectively.

Results:

ADR significantly reduced the plasma level of Ang-(1–7) and the expression of myocardial Mas receptor and myocardial AT₂R, while significantly increased the expression of myocardial AT1R. Treatment with telmisartan and losartan effectively increased the plasma level of Ang-(1–7) and suppressed myocardial AT1R expression, but did not influence the expression of Mas receptor and AT₂R.

Conclusion:

The protective effects of telmisartan and losartan in ADR-induced heart failure may be partially due to regulation of circulating Ang-(1–7) and myocardial AT1R expression.