The Bioactive Properties of Carotenoids from Lipophilic Sea buckthorn Extract (Hippophae rhamnoides L.) in Breast Cancer Cell Lines

In women, breast cancer is the most commonly diagnosed cancer (11.7% of total cases) and the leading cause of cancer death (6.9%) worldwide. Bioactive dietary components such as Sea buckthorn berries are known for their high carotenoid content, which has been shown to possess anti-cancer properties. Considering the limited number of studies investigating the bioactive properties of carotenoids in breast cancer, the aim of this study was to investigate the antiproliferative, antioxidant, and proapoptotic properties of saponified lipophilic Sea buckthorn berries extract (LSBE) in two breast cancer cell lines with different phenotypes: T47D (ER+, PR+, HER2-) and BT-549 (ER-, PR-, HER2-). The antiproliferative effects of LSBE were evaluated by an Alamar Blue assay, the extracellular antioxidant capacity was evaluated through DPPH, ABTS, and FRAP assays, the intracellular antioxidant capacity was evaluated through a DCFDA assay, and the apoptosis rate was assessed by flow cytometry. LSBE inhibited the proliferation of breast cancer cells in a concentration-dependent manner, with a mean IC₅₀ of 16 µM. LSBE has proven to be a good antioxidant both at the intracellular level, due to its ability to significantly decrease the ROS levels in both cell lines (p = 0.0279 for T47D, and p = 0.0188 for BT-549), and at the extracellular level, where the ABTS and DPPH inhibition vried between 3.38-56.8%, respectively 5.68-68.65%, and 35.6 mg/L equivalent ascorbic acid/g LSBE were recorded. Based on the results from the antioxidant assays, LSBE was found to have good antioxidant activity due to its rich carotenoid content. The flow cytometry results revealed that LSBE treatment induced significant alterations in late-stage apoptotic cells represented by 80.29% of T47D cells (p = 0.0119), and 40.6% of BT-549 cells (p = 0.0137). Considering the antiproliferative, antioxidant, and proapoptotic properties of the carotenoids from LSBE on breast cancer cells, further studies should investigate whether these bioactive dietary compounds could be used as nutraceuticals in breast cancer therapy.

Modulatory effect of curcumin analogs on the activation of metalloproteinases in human periodontal stem cells

Periodontitis progresses due to increased levels of active metalloproteinases (MMPs) and the imbalance between MMPs and their tissue inhibitors (TIMPs). Natural curcumin limits the lytic activity of MMPs but has low cellular uptake. Use of synthetic curcumin analogs could be a means of overcoming this limitation of treatment efficiency. Human periodontal stem cells were isolated from gingival tissue, gingival ligament fibers, periodontal ligament, and alveolar bone. The effect of five synthetic curcumin analogs was compared with that of natural curcumin by assessing cytotoxicity [by 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) assay], the cellular uptake (by fluorometry), the proteolytic activities of MMP-2 and -9 (by zymography), and the levels of TIMP-1 (by ELISA). Our results indicated increased cytotoxicity of synthetic curcumins for doses between 100 and 250 μM. At a concentration of 10 μM, cellular uptake of synthetic curcumins varied depending on their chemical structure. The curcumin compounds modulated pro-MMP-2 levels and increased TIMP-1 production. There was no detectable synthesis of pro-MMP-9 and no activation of MMPs 2 and 9. Gingival tissue and gingival ligament fiber stem cells were most responsive to treatment, showing inverse correlations between pro-MMP-2 and TIMP-1 levels. In conclusion, synthetic curcumins influenced the balance between pro-MMP-2 and TIMP-1 in human periodontal stem cells in vitro, and this could open perspectives for their application as adjuvants in periodontal therapy.

Effects of silver nanoparticles functionalized with Cornus mas L. extract on architecture and apoptosis in rat testicle

Aim: To assess ultrastructural changes, alterations in matrix metalloproteinase activity and apoptosis induced by silver nanoparticles (AgNPs) in the rat testicle. Materials & methods: For 45 days, two groups of animals received different doses of AgNPs (0.8 and 1.5 mg/kg b.w.), and a control group was given the buffer used as vehicle for AgNPs. At 7 and 15 days post-treatment, transmission electron microscopy, TUNEL assay, evaluation of NFkB, pNFkB, p53, Bcl-2 and Nrf2 expressions were performed on the removed testes. Results: Transmission electron microscopy revealed severe ultrastructural changes of interstitial tissue and seminiferous epithelium sustained by positive signal for apoptosis. The promatrix metalloproteinase-2 activity and NFkB, Bcl-2 expressions were increased, mainly at 7 days. Conclusion: AgNPs induced severe cell lesions identified even a long time after the exposure.

The effect of Sambucus nigra L. extract and phytosinthesized gold nanoparticles on diabetic rats

Nanomaterials such as gold nanoparticles (NPs) conjugated with natural products have shown good results in lowering the glycated hemoglobin and have an anti-inflamatory effect. The aim of our study is to evaluate the antidiabetic effect of NPs functionalized with Sambucus nigra L. (SN) extract on experimental model of diabetes in rats. Diabetes was induced to 18 Wistar male rats (n=6) by a single intramuscular injection of streptozotocin (30mg/kg body weight - b.w.). SN extract (15mg/kg b.w.), NPs (0.3mg/kg b.w.) and vehicle (normal saline) were administered by gavage once a day, every morning, for 2 weeks. Other 18 animals were used as control groups and were treated with the same compounds, at the same time. Afterwards, blood, liver and muscle samples were taken to assess the oxidant/antioxidant status and the liver for the evaluation of metalloproteinases (MMP)-2 and 9 activities, COX-2 and NFKB expressions and for immunohistochemistry. Serum glycemia, cholesterol, alanine aminotransferase (ALAT), aspartate aminotransferase (ASAT) were also measured. The administration of NPs extract increased the muscle and systemic GSH/GSSG ratio in the diabetic group vs. diabetic (p<0.03) or non-diabetic groups treated with vehicle (p<0.05) and decreased MDA levels compared to non-diabetic group (p<0.05). COX-2 expression (p<0.0001) and proMMP-2 activity (p<0.05) decreased after pretreatment with NPs in parallel with the reduction of Kupffer cells percent (<0.001). No morphological abnormalities were detected in histopathology. NPs present a great potential for further usage as adjuvants in the diabetic therapy due to the increase of antioxidant defence and reduction of MMPs activity and inflammation in liver tissue.

Natural chemopreventive alternatives in oral cancer chemoprevention

We studied the effect of grape seed extract Burgund Mare (BM) on oral carcinogenesis and compared it with that of curcumin (CU). Wistar rats were divided into six groups (n = 10): 4-nitro-quinoline-1-oxide (4NQO) oral carcinogenesis was induced to groups 1 - 5; groups 2 and 3 received BM and CU respectively during initiation and groups 4 and 5 BM and CU during post-initiation of carcinogenesis; group 6 represented the negative control group. Total malondialdehyde (MDA) and reduced glutathione (GSH) were assayed fluorometrically in oral tissue (gingival, jugal, palatal, lingual mucosa) and serum. Histopathological exam was performed and a dysplasia score given to each oral mucosal lesion. Ki67, cyclin D1, p63, Bcl2 and p53 were immunohistochemically evaluated. BM and CU reduced tissue MDA values elevated by 4NQO (P = 0.000). The difference between CU and BM effect was significant in the initiation (P = 0.02) but not in the post-initiation phase of carcinogenesis (P = 0.58). Tissue GSH levels decreased by 4NQO (P < 0.001) were not significantly modified by BM or CU. Serum MDA levels increased by 4NQO (P = 0.000) were significantly lowered by CU (P = 0.04) and BM (P = 0.04) during initiation and by CU during post-initiation of carcinogenesis (P = 0.01). CU was more potent than BM during post-initiation of carcinogenesis (P = 0.01). Serum GSH lowered by 4NQO (P = 0.55) was significantly decreased by BM and CU (P < 0.012), with no significant difference between groups receiving BM or CU. Moderate dysplasia was the most advanced dysplasia induced and gingival localization the most frequent. Both BM and CU lowered dysplasia scores, with BM being the most efficient during post-initiation of carcinogenesis (P = 0.001). Ki67, cyclin D1, p63, Bcl2 and p53 expression increased with dysplasia scores. BM showed chemopreventive properties during initiation and post-initiation of oral carcinogenesis, reducing local and general oxidative stress and the intensity of dysplasia. During post-initiation of carcinogenesis BM and CU exhibited similar effects.

Vitis vinifera seeds extract for the modulation of cytosolic factors BAX-α and NF-kB involved in UVB-induced oxidative stress and apoptosis of human skin cells

Background and aims

The depletion of the ozone layer allows overexposure of the skin to UV radiation, which is prolonged due to the increasing life expectancy, together with inappropriate life habits contribute to the increasing incidence of cutaneous malignancies. Plant extracts with antioxidant capacities are frequently employed as a means to protect skin against ultraviolet (UV) radiations, thus preventing skin cancers. In the present study we assessed a red grape seed extract (GSE) potential capacities to reduce ultraviolet B (UVB) radiation-induced reactive oxygen species (ROS) and subsequent apoptosis in a human keratinocytes cell line (HaCaT). We identified molecules and pathways modulated by the GSE through which this may exert its photoprotective effect.

Methods

The GSE was standardized according to its polyphenolic content and the most important biologically active compounds, such as epigallocatechin and epicatechin, catechin hydrate, procyanidin B and gallic acid were evidenced by high-performance liquid chromatography. According to the plant extract cytotoxicity on the HaCaT cell line, two concentrations were selected for testing from the non-toxic range: GSE₁ (37.5 μgEqGA/ml) and GSE₂ (75 μgEqGA/ml). The level of ROS was evaluated with CM-H₂DCFDA assay, while apoptosis, Bax-α and NF-kβ p65 proteins with ELISA and confirmed by western-blot.

Results

Both concentrations of the extract decreased the level of ROS in UVB-irradiated keratinocytes (p<0.001), whereas apoptosis and Bax-α pro-apoptotic protein were only reduced by the higher concentration (GSE₂). The NF-kB p65 protein level registered increasing values in time after UVB exposure of the cells, while the tested plant extract re-established its level when its smaller concentration was used (GSE₁).

Conclusion

These results encourage further studies on this extract in order to identify other molecules and pathways through which this extract might exert its beneficial effects and also recommend its use as a potential photoprotective agent.

Gallium phosphinoarylbisthiolato complexes counteract drug resistance of cancer cells

In cancer therapy the platinum-based drugs are used frequently with a good clinical outcome, but besides unwanted side effects which occur, the tumour cells subjected to treatment are prone to develop tolerance or even multidrug resistance (MDR). Metal compounds with a central atom other than platinum are efficient in targeting the chemoresistant cells, therefore the biological outcome of two recently synthesized gallium phosphinoarylbisthiolato complexes was studied, having the formula [X][Ga{PPh(2-SC6H4)2-κ(3)S,S',P}{PPh(2-SC6H4)2-κ(2)S,S'}] where [X] is either the NEt3H (1) or PPh4 (2) cation. Compounds 1 and 2 display in vitro cytotoxicity against both platinum-sensitive and platinum-resistant cell lines (A2780 and A2780cis). Morphological and ultrastructural evidence points toward their capacity to impair tumour cells survival. This behaviour is based on malignant cells capacity to selectively intake gallium, and to bind to the cellular DNA. They are able to cause massive DNA damage in treated cancer cells, focusing on 7-methylguanine and 8-oxoguanine sites and oxidizing the pyrimidine bases; this leads to early apoptosis of a significant percent of treated cells. The intrinsic and extrinsic apoptotic pathways are influenced through the modulation of gene expression following the treatment with complexes 1 and 2, which accompanies the negative regulation of P-glycoprotein 1 (Pgp-1), an important cellular ABC-type transporter from the multidrug resistance (MDR) family. The studied Ga(III) compounds demonstrated the capacity to counteract the chemoresistance mechanisms in the tumours defiant to standard drug action. Compound 2 shows a good anticancer potential and it could represent an alternative to platinum-based drugs especially in the situation of standard treatment failure.

Metformin associated with photodynamic therapy--a novel oncological direction

The aim of our study was to assess the effect of the combined treatment of Metformin (Metf) and 5, 10, 15, 20-tetra-sulfophenyl-porphyrin (TSPP)-mediated photodynamic therapy (PDT) on an in vivo tumour model. Wistar male rats were divided in 6 groups: group 1, treated with TSPP; groups 2 and 4 treated with TSPP and Metf, respectively, and irradiated 24h thereafter; group 3 was treated with Metf and the last two groups received the combined treatment, Metf administered prior (group 5) or after (group 6) irradiation. 72 h from the start of the treatment, tumour tissue was sampled for the investigation of oxidative and nitrosative stress. The apoptotic rate, inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 expressions and matrix metalloproteinases activities were also quantified. Malondialdehyde and glutathione levels were significantly elevated in the groups treated with combined therapy (p<0.05). Metf associated with TSPP-PDT reduced iNOS and COX-2 expressions and enhanced nitrotyrosine levels in both therapeutic regimens. Peroxynitrate formation and its cytotoxic effect on tumour cells were related to an elevated index of apoptosis and necrosis. Moreover, MMP-2 activity reached a minimum in the groups which received combined therapy. Our results confirmed that the association of Metf with PDT might prove a new and promising oncological approach.

Metformin plus sorafenib highly impacts temozolomide resistant glioblastoma stem-like cells

PURPOSE

Glioblastoma stem cells (GSCs), responsible for the dismal disease prognosis after conventional treatments, are driven by overactive signaling pathways, such as PI3K/ AKT/mTOR and RAS/RAF/MAPK. The objective of our study was to target in vitro-GSCs by combining metformin (Met) as a mTOR inhibitor, with sorafenib (Soraf) as a RAF inhibitor.

METHODS

GSCs cultured under basal conditions were treated with Met, temozolomide (TMZ), Soraf, Met+TMZ and Met+Soraf; as untreated arm served as control. At 4 hrs of drug exposure, we measured the level of reactive oxygen species (ROS) by 2',7'-dichlorofluorescein diacetate (DCFDA) assay, apoptosis by prodium iodide (PI)-V Annexin staining and efflux pump activity by using the fluorescent dye rhodamine 123. At 24 hrs, we measured cell proliferation by 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay, apoptosis and malondialdehyde (MDA) levels. MTT results were compared with corresponding measurements on cultures of non-stem glioblastoma cells and osteoblasts.

RESULTS

Met+Soraf exerted the highest antiproliferative effects in GSCs and non-stem glioblastoma cells (p<0.001). Both Met and Soraf monotherapy exhibited a selective cytotoxic effect on GSCs (p<0.001), while no effect was detected on non-stem glioblastoma cells (p>0.05). Soraf, but not Met, impacted the proliferation of normal cells. Soraf displayed synergism with Met in producing high levels of ROS, decreasing efflux pump activity and generating the highest apoptotic rates when compared to either drug alone (p<0.001).

CONCLUSION

GSCs were highly sensitive to the combination of Met and Soraf which reduced cell proliferation, increased oxidative stress, inhibited efflux pump activity and ultimately killed GSCs. We strongly believe that these results warrant further in vivo exploration.

Oxaliplatin induces different cellular and molecular chemoresistance patterns in colorectal cancer cell lines of identical origins

Background

Cancer cells frequently adopt cellular and molecular alterations and acquire resistance to cytostatic drugs. Chemotherapy with oxaliplatin is among the leading treatments for colorectal cancer with a response rate of 50%, inducing intrastrand cross-links on the DNA. Despite of this drug’s efficiency, resistance develops in nearly all metastatic patients. Chemoresistance being of crucial importance for the drug’s clinical efficiency this study aimed to contribute to the identification and description of some cellular and molecular alterations induced by prolonged oxaliplatin therapy. Resistance to oxaliplatin was induced in Colo320 (Colo320R) and HT-29 (HT-29R) colorectal adenocarcinoma cell lines by exposing the cells to increasing concentrations of the drug. Alterations in morphology, cytotoxicity, DNA cross-links formation and gene expression profiles were assessed in the parental and resistant variants with microscopy, MTT, alkaline comet and pangenomic microarray assays, respectively.

Results

Morphology analysis revealed epithelial-to-mesenchymal transition in the resistant vs parental cells suggesting alterations of the cells’ adhesion complexes, through which they acquire increased invasiveness and adherence. Cytotoxicity measurements demonstrated resistance to oxaliplatin in both cell lines; Colo320 being more sensitive than HT-29 to this drug (P < 0.001). The treatment with oxaliplatin caused major DNA cross-links in both parental cell lines; in Colo320R small amounts of DNA cross-links were still detectable, while in HT-29R not. We identified 441 differentially expressed genes in Colo320R and 613 in HT-29R as compared to their parental counterparts (at least 1.5 -fold up- or down- regulation, p < 0.05). More disrupted functions and pathways were detected in HT-29R cell line than in Colo320R, involving genes responsible for apoptosis inhibition, cellular proliferation and epithelial-to-mesenchymal transition. Several upstream regulators were detected as activated in HT-29R cell line, but not in Colo320R.

Conclusions

Our findings revealed a more resistant phenotype in HT-29R as compared to Colo320R and different cellular and molecular chemoresistance patterns induced by prolonged treatment with oxaliplatin in cell lines with identical origins (colorectal adenocarcinomas).

New nanomaterials for the improvement of psoriatic lesions

The main purpose of the present paper is to emphasize the non-invasive effect of some new prepared nanomaterials on skin diseases (psoriasis) together with the procedures to obtain them. These new materials are based on gold nanoparticles and natural compounds extracted from native plants of the Adoxaceae family (European cranberrybush -Viburnum opulus L. and European black elderberry -Sambucus nigra L.) and possess a known anti-inflammatory activity mainly due to their high content of anthocyanins and other polyphenols. The nanomaterials were characterized by transmission electron microscopy (TEM), UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX) and thermogravimetric analysis (TGA). Studies in vivo and in vitro were made in order to determine the toxicity of the products. Based on the obtained nanomaterials, specific dermatological creams were prepared. Their effect on psoriatic lesions, in comparison with the hydrocortisone creams, was studied.

Calluna vulgaris extract modulates NF-κB/ERK signaling pathway and matrix metalloproteinase expression in SKH-1 hairless mice skin exposed to ultraviolet B irradiation

Photochemoprevention with natural products represents a new concept in the attempt to reduce the occurrence of skin cancer. However, the molecular mechanisms caused by ultraviolet light exposure remain still unclear. The aim of the study was to assess the mechanisms involved in the action of a Calluna vulgaris (Cv) extract, administered in single or multiple doses (10 consecutive days), on UVB-induced skin damage in SKH-1 hairless mice. The extract was topically applied 30 min before each UVB exposure in two doses (2.5 and 4 mg total polyphenolic content/40 μl/cm(2)). At 24 hours after the last treatment, total mitogen-activated protein kinase (p44/42MAPkinase, ERK 1/2), nuclear factor-κB (phospho-NF-κB p65), matrix metalloproteinases (MMP-2, MMP-9) and metalloproteinase inhibitor 1 (TIMP-1) levels were measured in skin using enzyme-linked immunosorbent assay (ELISA). MMP-2 and -9 activities were additionally evaluated by zymography. One topical application of Cv extract reduced the secretion (p<0.004) and inhibited MMP-9 activity UVB-mediated (54% inhibition) via inhibition of NF-κB activation (68% inhibition). In multiple UVB exposures, both doses of Cv extract induced the increase of ERK 1/2 level in correlation with activation of NF-κB and reduced the secretion (p<0.04) and activation of MMP-9 (62% inhibition). Pretreatment with Cv diminished the MMP-2 protein secretion only in one dose UVB-irradiated group (p<0.0001) and decreased TIMP-1 level (p<0.001). These results demonstrated the dual behavior of Cv extract in skin protection against single versus multiple doses of UVB irradiation.

Photoprotective effect of Calluna vulgaris extract against UVB-induced phototoxicity in human immortalized keratinocytes

There is an increasing interest in the use of natural antioxidants as photoprotective agents against skin damages produced by ultraviolet radiation. The aim of our study was to investigate the protective effect of a Calluna vulgaris extract in human keratinocytes (HaCaT) exposed to ultraviolet B (UVB) radiation. HaCaT cells were treated with C. vulgaris extract 30 minutes prior to irradiation with UVB. The protective effect was evaluated by assessing cell viability using tetrasolium salt (MTT) assay; the generation of lipid peroxides was evaluated using malondialdehide assay (MDA); and DNA damage was evaluated using the comet assay and the quantification by ELISA of specific DNA photolesions [i.e., cyclobutane-pyrimidine dimers (CPDs) and 6-4 photoproducts (6-4PPs)]. After irradiation with cytotoxic doses of UVB (300 and 500 mJ/cm(2)), HaCaT cells pretreated with C. vulgaris extract (50 μg GAE/ml) showed significantly increased viability compared to control cells exposed to UVB only. Irradiation alone increased MDA levels in a dose-dependent fashion. Pretreatment with 12 μg GAE/ml extract lowered MDA levels both at 100 mJ/cm(2) (ρ<0.01) and 300 mJ/cm(2) (ρ<0.001). Treatment with C. vulgaris extract before exposure to UVB also reduced DNA damage: Lesion scores in a comet assay were significantly reduced at UVB doses of 50 mJ/cm2 (ρ<0.01) and 100 mJ/cm(2) (ρ<0.05), while CPDs and 6-4PPs (via ELISA) were significantly lower after irradiation with 100 mJ/cm(2) in the protected cells (ρ<0.05 for CPDs and ρ<0.001 for 6-4PPs). These results recommend the use of the C. vulgaris extract as photoprotective agent, in combination with sunscreens and/or other natural products with similar or complementary properties.

Possible in vivo mechanisms involved in photodynamic therapy using tetrapyrrolic macrocycles

Photodynamic therapy (PDT) mediated by oxidative stress causes direct tumor cell damage as well as microvascular injury. To improve this treatment new photosensitizers are being synthesized and tested. We evaluated the effects of PDT with 5,10,15,20-tetrakis(4-methoxyphenyl)-porphyrin (TMPP) and its zinc complex (ZnTMPP) on tumor levels of malondialdehyde (MDA), reduced glutathione (GSH) and cytokines, and on the activity of caspase-3 and metalloproteases (MMP-2 and -9) and attempted to correlate them with the histological alterations of tumors in 3-month-old male Wistar rats, 180 ± 20 g, bearing Walker 256 carcinosarcoma. Rats were randomly divided into five groups: group 1, ZnTMPP+irradiation (IR) 10 mg/kg body weight; group 2, TMPP+IR 10 mg/kg body weight; group 3, 5-aminolevulinic acid (5-ALA+IR) 250 mg/kg body weight; group 4, control, no treatment; group 5, only IR. The tumors were irradiated for 15 min with red light (100 J/cm², 10 kHz, 685 nm) 24 h after drug administration. Tumor tissue levels of MDA (1.1 ± 0.7 in ZnTMPP vs 0.1 ± 0.04 nmol/mg protein in control) and TNF-α (43.5 ± 31.2 in ZnTMPP vs 17.3 ± 1.2 pg/mg protein in control) were significantly higher in treated tumors than in controls. Higher caspase-3 activity (1.9 ± 0.9 in TMPP vs 1.1 ± 0.6 OD/mg protein in control) as well as the activation of MMP-2 (P < 0.05) were also observed in tumors. These parameters were correlated (Spearman correlation, P < 0.05) with the histological alterations. These results suggest that PDT activates the innate immune system and that the effects of PDT with TMPP and ZnTMPP are mediated by reactive oxygen species, which induce cell membrane damage and apoptosis.

Enhanced chemoresistance and tumor sphere formation as a laboratory model for peritoneal micrometastasis in epithelial ovarian cancer

BACKGROUND AND PURPOSE

Ovarian cancers are composed of heterogeneous cell populations, including highly proliferative immature precursors and differentiated cells that may belong to different lineages. The main reason why epithelial ovarian cancer is difficult to treat is the unusual mechanism of dissemination that involves local invasion of pelvic and abdominal organs. But, unlike many other carcinomas, initial dissemination rarely requires blood or lymph vessels. Because it has been proven that aggregates of malignant cells within the ascites of patients diagnosed with ovarian cancer represent an impediment to cure such cancers, in the present study we adopted suspension culture combined with anti-cancer regimens as a laboratory strategy for research of the initial process of peritoneal micrometastasis.

EXPERIMENTAL DESIGN

MLS human ovarian cancer cells were cultured in serum-free medium. Cells of passage eight were treated in combination with the anticancer agent doxorubicin at different peak plasma concentrations for 24 hours, and then maintained under suspension culture. The acquired increased aggressiveness properties was confirmed by multidrug resistance assays and by their ability to grow in an anchorage-independent manner in vitro as tumor spheroids.

RESULTS

Cells selected after chemotherapy had a increased proliferative potential, eliminated Rhodamine 123 in culture and also formed spheroids in suspension.

CONCLUSIONS

Here we present direct evidence that the metastasis of human ovarian cancer may be a result of transformation and dysfunction of immature precursor cells in the ovary. Also, spheroid formation may represent a key component of chemotherapy recurrence and a better understanding of these 3D structures can contribute to the development of new treatments for metastatic carcinoma.

Antiproliferative effect and genotoxicity of novel synthesized palladium complexes with organoarsenic ligands

Three new palladium complexes with general formula [PdCl(2)L(2)], where L=heterofunctional organoarsenic ligand: (2-isopropoxyphenyl)diphenylarsine (1), (2-methoxyphenyl)-diphenylarsine (2) and (2-hydroxyphenyl)diphenylarsine (3) have been synthesized and fully characterized, including X-ray crystallographic data. Their potential antitumor effect and genotoxicity have been studied as well. The viability test performed on human tumor (MLS) and normal (Hfl-1) cell lines indicates significant cytotoxicity of complexes, which is higher in tumor cells than in normal cells. The lethal doses are comparable with those of standard metal-based chemotherapeutical drugs (carboplatin and oxaliplatin). These palladium complexes exhibit a higher cytotoxicity against tumor cells as against normal cells in vitro. A new static cytometric method was developed and simultaneously the classic AnnexinV test was performed. Complex 2 has an important capacity to induce apoptosis in tumor cells. The apoptotic process is triggered due to the interaction of these complexes with secondary structure of DNA in treated cells. The alkaline single-cell gel assay shows that the level of DNA damages induced by compounds 2 and 3 are significantly higher in tumor cells as in normal cells. These studies shown that complexes 1, 2 and 3 have biologic activity, the effect of complex 2 being superior to its platinum analogues, attributable to its structure.

Effects of 60Co gamma-rays on human osteoprogenitor cells

BACKGROUND

Radiation therapy is one of the most efficient treatments of neoplastic diseases used worldwide. However, patients who undergo radiotherapy may develop side effects that can be life threatening because tissue complications caused by radiation-induced stem cell depletion may result in structural and functional alterations of the surrounding matrix. This treatment also damages the osteogenic activity of human bone marrow by suppressing osteoblasts, leading to post-irradiation sequelae. Even if widely used in oncology, there is still little information on the fate and potential therapeutic efficacy of electromagnetic rays.

MATERIAL AND METHODS

We addressed this question using both human mesenchymal stem cells and osteoblasts. Monoclonal antibody characterization identified specific surface markers for stem cells (SSEA-4, CD29, CD105, Oct 3, Nanog and SOX2) and osteoblasts (Osteopontin and Osteonectin). The technique of anti-alkaline phosphatase FITC-staining demonstrated the presence of this specific ectoenzyme. Cells were cultured in complex osteogenic medium (DMEM, 15% fetal calf serum, non-essential amino acids, L-glutamine, dexametazone, ascorbic acid, insulin, TGF-beta, BMP-2 and beta-glycero-phosphate) after being irradiated at 0.5 Gy, 1 Gy, 2 Gy and 4 Gy using a Theratron 1000 60Co source. The viability of irradiated cells was assessed using Trypan Blue staining. The comparison between cell lineages after culture in osteogenic media regarding phenotypical characterization and the intensity of the mineralization process included histology stainings (Alizarin Red S, Alcian Blue and von Kossa), and the MTT-based proliferation assay.

RESULTS

After irradiation, the proliferation and differentiation of osteoprogenitor cells is dose-dependent.

CONCLUSIONS

This study is one among the first papers investigating the biophysics of low-dose gamma-irradiation on stem cell culture, focusing on the potential applications in radiation oncology and various palliative treatments.

Effects of PDT with 5-aminolevulinic acid and chitosan on Walker carcinosarcoma

Porphyrins and new chitosan hydrogels based composites with porphyrins are used as active cytotoxic antitumor agents in photodynamic therapy (PDT).

AIM

The present study evaluates the effects of photodynamic therapy (PDT) with 5-aminolevulinic acid (5-ALA) and 5-ALA associated with chitosan (CS) using Walker carcinosarcoma in rats as experimental model.

METHODS

The animals were irradiated with red light ( lambda = 685 nm, D = 50 J/cm(2), 15 min) 3 h after i.p. administration of 5-ALA (250 mg/kg b.w.) or a mixture of 5-ALA (250 mg/kg b.w.) and CS (1.5 mg/kg b.w.). The animals were sacrificed at 1, 3, 6, 24 h and 14 days after the treatment. The effects of PDT were investigated by morphological studies, monitoring the 5-ALA induced protoporphyrin IX (Pp IX) level in tumor tissue and serum, MMP 2 and 9 (gelatinases) activity in tumor and malondialdehyde level (MDA), marker of the lipoperoxidation process, in tumor and serum.

RESULTS

Zymography revealed an increased activity of MMP 2 in tumors from animals treated with 5-ALA PDT. PDT with 5-ALA induced a higher lipid peroxidation in tumor tissue compared with 5-ALA-CS. CS associated to 5 ALA PDT enhanced the accumulation of PS in tumors inducing earlier necrotic changes. In the same time CS reduced MMP 2 activity.

CONCLUSION

Our results suggest that MMPs activation and oxygen reactive species are involved in PDT effects.