Concentration-Dependent Pro- and Antitumor Activities of Quercetin in Human Melanoma Spheroids: Comparative Analysis of 2D and 3D Cell Culture Models

Quercetin, a dietary flavonoid found in fruits and vegetables, has been described as a substance with many anti-cancer properties in a variety of preclinical investigations. In the present study, we demonstrate that 2D and 3D melanoma models exhibit not only different sensitivities to quercetin, but also opposite, cancer-promoting effects when metastatic melanoma spheroids are treated with quercetin. Higher concentrations of quercetin reduce melanoma growth in three tested cell lines, whereas low concentrations induce the opposite effect in metastatic melanoma spheroids but not in the non-metastatic cell line. High (>12.5 µM) or low (<6.3 µM) quercetin concentrations decrease or enhance cell viability, spheroid size, and cell proliferation, respectively. Additionally, melanoma cells cultivated in 2D already show significant caspase 3 activity at very low concentrations (>0.4 µM), whereas in 3D spheroids apoptotic cells, caspase 3 activity can only be detected in concentrations ≥12.5 µM. Further, we show that the tumor promoting or repressing effect in the 3D metastatic melanoma spheroids are likely to be elicited by a precisely controlled regulation of Nrf2/ARE-mediated cytoprotective genes, as well as ERK and NF-κB phosphorylation. According to the results obtained here, further studies are needed to better characterize the mechanisms of action underlying the pro- and anti-carcinogenic effects of quercetin on human melanomas.

Progression-Dependent Altered Metabolism in Osteosarcoma Resulting in Different Nutrient Source Dependencies

Osteosarcoma (OS) is a primary malignant bone tumor and OS metastases are mostly found in the lung. The limited understanding of the biology of metastatic processes in OS limits the ability for effective treatment. Alterations to the metabolome and its transformation during metastasis aids the understanding of the mechanism and provides information on treatment and prognosis. The current study intended to identify metabolic alterations during OS progression by using a targeted gas chromatography mass spectrometry approach. Using a female OS cell line model, malignant and metastatic cells increased their energy metabolism compared to benign OS cells. The metastatic cell line showed a faster metabolic flux compared to the malignant cell line, leading to reduced metabolite pools. However, inhibiting both glycolysis and glutaminolysis resulted in a reduced proliferation. In contrast, malignant but non-metastatic OS cells showed a resistance to glycolytic inhibition but a strong dependency on glutamine as an energy source. Our in vivo metabolic approach hinted at a potential sex-dependent metabolic alteration in OS patients with lung metastases (LM), although this will require validation with larger sample sizes. In line with the in vitro results, we found that female LM patients showed a decreased central carbon metabolism compared to metastases from male patients.

Characterization of a Novel Mouse Model of Spontaneous Human Lung Cancer Metastasis

To identify new strategies against lung metastasis and understand the underlying mechanisms, a highly metastatic pulmonary large cell carcinoma cell line model (801BL) was established through two rounds of in vivo selection using a nude mouse xenograft model. Satellite tandem repeat (STR) analysis confirmed the same genomic background of the newly established metastatic cell line 801BL as the non-metastatic 801C and low-metastatic 801D counterparts. Our study showed that 100% of mice (8 out of 8) injected subcutaneously with 801BL cells developed lung metastatic tumors, while none of the mice injected with 801C cells had lung metastasis (p<0.0001). Highly metastatic 801BL cells showed alterations in morphology and invasion capability when compared with 801C and/or 801D cell lines A comparative proteomic analysis between 801BL and 801C followed by bioinformatics analysis revealed significant alterations in several dominant cell signalling networks in the highly metastatic cell line. Western blot confirmed the proteomic findings for several proteins from each signalling network. Since the highly metastatic cell line and its non-metastatic counterpart share the identical genetic background, this model provides a powerful tool for study of the mechanisms underlying lung cancer metastasis.

Synthesis, Anti-Cancer and Anti-Migratory Evaluation of 3,6-Dibromocarbazole and 5-Bromoindole Derivatives

In this study, a new series of N-alkyl-3,6-dibromocarbazole and N-alkyl-5-bromoindole derivatives have been synthesized and evaluated in vitro as anti-cancer and anti-migration agents. Cytotoxic and anti-migratory effects of these compounds were evaluated in MCF-7 and MDA-MB-231 breast cancer cell lines and an insight on the structure-activity relationship was developed. Preliminary investigations of their anti-cancer activity demonstrated that several compounds have moderate antiproliferative effects on cancer cell lines with GI50 values in the range of 4.7–32.2 µM. Moreover, carbazole derivatives 10, 14, 15, 23, and 24 inhibit migration activity of metastatic cell line MDA-MB-231 in the range of 18–20%. The effect of compounds 10, 14, and 15 in extension of invadopodia and filopodia was evaluated by fluorescence microscopy and results demonstrated a reduction in actin-based cell extensions by compounds 10 and 15.

ANTICANCER AND ANTIMICROBIAL POTENTIAL OF BARLERIA PRIONITIS LEAVES ETHANOL EXTRACT

Objective: The present study was focused to screen traditionally used Barleria prionitis for anticancer effects against various cell lines and antimicrobial effect against various pathogenic strains of bacteria and fungi.Methods: Extraction of Barleria prionitis leaves in ethanol was done by the Soxhlet method. After extraction, phytochemical estimation of these seven secondary metabolites like alkaloids, flavonoids, anthraquinones, saponins, terpenoids, tannins, and cardiac glycosides was done as per the protocols of Kokate. Minimum Inhibitory Concentration (MIC) effect of Barleria leaf ethanol (BLE) was done by the dilution method on five bacterial and five fungal strains. Further analysis (anticancer activity) was done with SRB (Sulphorhodamine B) assay. Statistical analysis of antimicrobial and anticancer activity was done by using MS Excel 2007 to±standard deviation and student t-test.Results: Barleria leaf extract with ethanol is a non-polar solvent extract and considered as the best solvent to extract the maximum number of secondary metabolites like alkaloids, saponins, flavonoids, and tannins. BLE extract gave excellent MIC (Minimum Inhibitory Concentration) effects against pathogenic bacteria and pathogenic fungal strains. BLE had highly effective activity against Pseudomonas aeruginosa with 1.25 mg MIC, the OD value of the sample was 0.02±0.0005 (±SD) with 0.0211-0.0245 range. MIC against fungal strains had effective activity against Candida vaginitis with 6.25 mg, the OD value of the sample was 0.02±0.0003 (±SD) with 0.0213-0.0232 range. BLE extract had given more than 70% inhibition against breast cell lines (MCF-7) and 75.16% inhibition of DLD1 cell lines; it was near to Doxorubicin antibiotic (81%). Breast metastatic cell line (MDMAMB-468) was found 60% inhibited with BLE extract and there was a great difference in the results of Doxorubicin. Out of six experimented cell lines, BLE gave very good inhibition for two cell lines, i.e. Breast (MCF-7) and Colon cell lines (DLD-1).Conclusion: BLE extract had shown the best antimicrobial and antifungal effect, against Pseudomonas aeruginosa and Candida vaginitis respectively. BLE also showed an anticancer effect against Lung cell lines (A549), Breast cancer cell line (MCF-7), Breast metastatic cell line (MDMAMB-468), Colon cell line (DLD-1) and lung metastatic cell line (NCIH358) at a statistically significant level (p=<0.05). It did not give any significant results against the colon metastatic cell line (SW620).

Standard melanoma-associated markers do not identify the MM127 metastatic melanoma cell line

Reliable identification of different melanoma cell lines is important for many aspects of melanoma research. Common markers used to identify melanoma cell lines include: S100; HMB-45; and Melan-A. We explore the expression of these three markers in four different melanoma cell lines: WM35; WM793; SK-MEL-28; and MM127. The expression of these markers is examined at both the mRNA and protein level. Our results show that the metastatic cell line, MM127, cannot be detected using any of the commonly used melanoma-associated markers. This implies that it would be very difficult to identify this particular cell line in a heterogeneous sample, and as a result this cell line should be used with care.