Role of acidic cell organelles in the higher nonmelanoma retention of melanoma markers based on N-(2-dialkylaminoethyl)benzamides and the cytotoxicity of alkylating benzamides.

Melanoma markers based on both N-(2-dialkylaminoethyl)benzamides and lysosomotropic agents comprise a N-(2-dialkylaminoethyl)aminocarbamoyl pharmacophore, suggesting that benzamides and lysosomotropic probes should show affinity to melanoma and acidic cell organelles. We prepared novel fluorescent N-(2-dialkylaminoethyl)benzamides to prove this presumption. Lysosomotropic probes showed a melanin affinity comparable to benzamides.

Alkylating benzamides with melanoma cytotoxicity: experimental chemotherapy in a mouse melanoma model.

The in-vivo antineoplastic potential of the alkylating N-(2-dialkylaminoethyl)benzamides BZA1 and BZA2, novel melanoma targeted anticancer drugs, was evaluated in a mouse melanoma model with nude mice bearing subcutaneous SkMel28, B16 or WM266-4. The maximal tolerated dose (MTD) for the intraperitoneal application of both agents was found to be 24 mg/kg. Treatment was initiated with an intraperitoneal injection of 8 mg/kg of BZA1 or BZA2 on days 0, 2 and 4 in the case of B16 melanoma on days 0, 1 and 2 after the onset of the experiment, when the mean tumor diameter ranged within 4-6 mm.

Radioiodine therapy of hepatoma using targeted transfer of the human sodium/iodide symporter gene.

Unlabelled: We investigated the feasibility of radioiodine therapy targeting hepatoma cells (MH3924A) by tissue-specific expression of the human sodium/iodide symporter (hNIS) gene directed by the murine albumin enhancer and promoter (mAlb).

Methods: The cell-specific transcriptional activity of mAlb was examined by a luciferase assay in several transiently transfected cell lines. MH3924A cells were stably transfected with the recombinant retroviral vector, in which hNIS complementary DNA expression was driven by mAlb and coupled to hygromycin resistance gene using an internal ribosomal entry site (IRES).

Fluorophor-labeled spermidine derivatives as fluorescent markers in optical tumor imaging.

Up-regulation of polyamine transporters on the surface of tumor cells and the internalization of biogenic polyamines by active transport processes may be exploited for the accumulation of spermidine derivatives as reporter molecules. We have synthesized and tested fluorophor-labeled spermidine derivatives for the development of a new class of intraoperative tumor imaging agents. In vitro uptake experiments and initial in vivo imaging studies illustrated that fluorophor tagged spermidine derivatives show tumor accumulation.

Effects of Pax8 and TTF-1 thyroid transcription factor gene transfer in hepatoma cells: imaging of functional protein-protein interaction and iodide uptake.

Unlabelled: The thyroid transcription factors TTF-1 and Pax8 cooperate in the transcriptional activation of thyroid-specific genes such as thyroglobulin (Tg), thyroperoxidase (TPO), and sodium/iodide symporter (NIS).

Methods: Dog TTF-1 (dTTF-1) and the human Pax8 (hPax8) gene were transfected in Morris hepatoma (MH3924A) cells to investigate (a) the possible visualization of functional protein-protein interaction and (b) the induction of thyroid-specific gene expression. In MH3924A cell lines expressing dTTF-1, hPax8, or both, the activation of human Tg (hTg), human TPO (hTPO), or rat NIS (rNIS) promoter/enhancer was measured using firefly luciferase reporter constructs.

Transfer of the sFLT-1 gene in Morris hepatoma results in decreased growth and perfusion and induction of genes associated with stress response.

Purpose: Inhibition of tumor angiogenesis is emerging as a promising target in the treatment of malignancies. Therefore, monitoring of antiangiogenic approaches with functional imaging and histomorphometrical analyses are desirable to evaluate the biological effects caused by this treatment modality.

Experimental Design: Using a bicistronic retroviral vector for transfer of the soluble receptor for the vascular endothelial growth factor (sFLT) hepatoma (MH3924A) cell lines with sFLT expression were generated.

Iodide kinetics and dosimetry in vivo after transfer of the human sodium iodide symporter gene in rat thyroid carcinoma cells.

Unlabelled: Transfer of the human sodium iodide symporter (hNIS) has been proposed as a new principle of cancer gene therapy. This study evaluates the iodide kinetics and dosimetry of iodide in hNIS-expressing thyroid carcinoma cells under optimized conditions.

Methods: Using a bicistronic retroviral vector for the transfer of the hNIS and the hygromycin resistance gene, hNIS-expressing rat thyroid carcinoma cell lines were generated.

Tumor-specific gene expression using regulatory elements of the glucose transporter isoform 1 gene.

In order to achieve tumor-specific targeting of adeno-associated virus (AAV)-mediated gene expression, the promoter of the glucose transporter isoform 1 (GLUT1) gene was cloned upstream of the enhanced green fluorescence protein (EGFP) and the herpes simplex virus thymidine kinase (HSVtk) gene. FACS analysis performed at 48 h after transient infection with rAAV/cytomegalovirus (CMV)egfp viral particles revealed an increase of fluorescence in all the cell lines tested. However, EGFP expression under control of the GLUT1 promoter element (rAAV/GTI-1.

Tumour-specific activation of the sodium/iodide symporter gene under control of the glucose transporter gene 1 promoter (GTI-1.3).

Targeted transfer of a functionally active sodium iodide symporter (NIS) into tumour cells may be used for radioiodine therapy of cancer. Therefore, we investigated radioiodine uptake in a hepatoma cell line in vitro and in vivo after transfer of the sodium iodide symporter ( hNIS) gene under the control of a tumour-specific regulatory element, the promoter of the glucose transporter 1 gene (GTI-1.3).