Since neural progenitor cells can engraft stably into brain tumors and differentiate along the neuronal and glial line, we tested the hypothesis that transplanted cytosine deaminase (CD)-expressing ST14A cells (an immortalized neural progenitor cell line) can convert locally 5-fluorocytosine (5-FC) into 5-fluorouracil (5-FU) and produce a regression of glioma tumors. ST14A, retrovirally transduced with the E. coli CD gene, showed a strong bystander effect on glioma cells as assessed by in vitro assay. Intracerebral injection of C6 glioma cells generated a rapidly growing tumoral mass. DiI prelabeled ST14A, coinjected into the rat brain with C6 glioma cells, survived in the tumoral mass up to 10 days and their number was not affected by in vivo 5-FC treatment. In contrast, a significant decrease of the glioma tumoral mass (À50%) was observed in 5-FC-treated rats. 5-FC had no effect on the tumor in the absence of CD-expressing ST14A cells. Our results support the feasibility of systems based on intratumoral transplantation of prodrug-converting cells for brain tumor therapy.
A multivariate analysis of the National Cancer Institute gene expression database is reported here. The soft independent modelling of a class analogy approach achieved cell line classification according to histological origin. With the PCA method, based on the expression of 9605 genes and ESTs, classification of colon, leukaemia, renal, melanoma and CNS cells could be performed, but not of lung, breast and ovarian cells. Another multivariate procedure, called partial least squares discriminant analysis (PLS-DA), provides bioinformatic clues for the selection of a limited number of gene transcripts most effective in discriminating different tumoral histotypes. Among them it is possible to identify candidates in the development of new diagnostic tests for cancer detection and unknown genes deserving high priority in further studies. In particular, melan-A, acid phosphatase 5, dopachrome tautomerase, S100-beta and acid ceramidase were found to be among the most important genes for melanoma. The potential of the present bioinformatic approach is exemplified by its ability to identify differentiation and diagnostic markers already in use in clinical settings, such as protein S-100, a prognostic parameter in patients with metastatic melanoma and a screening marker for melanoma metastasis.
Copper homeostasis and distribution is strictly regulated by a network of transporters and intracellular chaperones encoded by a group of genes collectively known as copper homeostasis genes ( CHG s). In this work, analysis of The Cancer Genome Atlas database for somatic point mutations in colorectal cancer revealed that inactivating mutations are absent or extremely rare in CHG s. Using oligonucleotide microarrays, we found a strong increase in mRNA levels of the membrane copper transporter 1 protein [ CTR 1; encoded by the solute carrier family 31 member 1 gene ( SLC 31A1 gene)] in our series of colorectal carcinoma samples. CTR 1 is the main copper influx transporter and changes in its expression are able to induce modifications of cellular copper accumulation. The increased SLC 31A1 mRNA level is accompanied by a parallel increase in transcript levels for copper efflux pump ATP 7A, copper metabolism Murr1 domain containing 1 ( COMMD 1), the cytochrome C oxidase assembly factors [synthesis of cytochrome c oxidase 1 ( SCO 1) and cytochrome c oxidase copper chaperone 11 ( COX 11)], the cupric reductase six transmembrane epithelial antigen of the prostate ( STEAP 3), and the metal‐regulatory transcription factors ( MTF 1, MTF 2) and specificity protein 1 ( SP 1). The significant correlation between SLC 31A1 , SCO 1 , and COX 11 mRNA levels suggests that this transcriptional upregulation might be part of a coordinated program of gene regulation. Transcript‐level upregulation of SLC 31A1 , SCO 1 , and COX 11 was also confirmed by the analysis of different colon carcinoma cell lines (Caco‐2, HT 116, HT 29) and cancer cell lines of different tissue origin ( MCF 7, PC 3). Finally, exon‐level expression analysis of SLC 31A1 reveals differential expression of alternative transcripts in colorectal cancer and normal colonic mucosa.
Bioassay-guided fractionation of the EtOAc crude extract from Sicilian almond hulls, a waste material from Prunus dulcis crop, allowed identification of 10 constituents, isolated as pure compounds (1-5, 7, and 10) or unseparable mixtures (5 + 6 and 8 + 9). All compounds were subjected to spectroscopic analysis and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide bioassay on MCF-7 human breast cancer cells. In addition to the main components oleanolic (1), ursolic (2), and betulinic (3) acids, the 2-hydroxy analogues alphitolic (4), corosolic (5), and maslinic (6) acids, as well as the related aldehydes, namely, betulinic (7), oleanolic (8), and ursolic (9), were identified. From a more polar fraction, the beta-sitosterol 3-O-glucoside (10) was also identified. A sample of commercially available betulin (11) was also included in bioassays as further support to a structure-activity relationship study. Betulinic acid showed antiproliferative activity toward MCF-7 cells (GI50 = 0.27 microM), higher than the anticancer drug 5-fluorouracil.
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