Artificial zinc(II) complexes regulate cell cycle and apoptosis-related genes in tumor cell lines.

Various proteins involved in transcriptional regulation possess highly selective DNA-binding domains, known as zinc fingers. However, little is known about small-molecule zinc(II) complexes in the regulation of gene expression and programmed cell death. A new family of zinc(II) complexes is reported, which might be useful against human cancer cells. By using template synthesis and in vitro cell-line screening, a set of zinc(II) complexes has been found to induce apoptosis of cancer cells and display single-reagent in vitro cytotoxicity. The method used to synthesize the molecules resulted in "built-in" luminescent behavior. Confocal optical imaging clearly demonstrated penetration through the cell membrane by these metal complexes. We have discovered that C3, the meso-zinc(II) complex is an extremely efficient regulator of the cell cycle and anti-apoptosis genes bcl-2 and bcl-xL. This study provides a new insight into the development of zinc(II) complexes as potential drugs.

Setup and characterization of a human head and neck squamous cell carcinoma xenograft model in nude rats.

OBJECTIVE: To develop and characterize a new head and neck cancer animal model. STUDY DESIGN: A human head and neck squamous cell carcinoma (HNSCC) xenograft model in nude rats was established via subcutaneous inoculation of a human-origin HNSCC cell line, SCC-4. The tumor was evaluated for growth characteristics, pathologic features by hematoxylin-eosin (HE) staining, and immunohistochemistry of epidermal growth factor receptor (EGFR). 2-[18F] fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography (PET) imaging characteristics were studied too. RESULTS: A new HNSCC animal model was successfully established. Tumor sizes reached about 1 cm3 on day 15 after tumor cell inoculation. HE staining pathology has confirmed that this tumor is a typical SCC. EGFR immunohistochemistry demonstrated this tumor model to be strongly EGFR positive. 18F-FDG PET study has shown that 18F-FDG accumulated in tumors. CONCLUSIONS: This study has demonstrated that this tumor model is an appropriate HNSCC tumor model for animal studies on HNSCC.

In vitro anticancer activities and optical imaging of novel intercalative non-cisplatin conjugates.

The first pi-conjugated macrocyclic diimine and triaza DNA-binding intercalators and their platinum(II) conjugates have been synthesized by direct Schiff base cyclocondensation. The in vitro anticancer activities of compounds 3, 4, and 5 were tested on five cancer cell lines: MCF-7, A549, P388, A2780, and A2780cisR. Ovarian tumors were included specifically to evaluate the new conjugates' ability to circumvent A2780cisR resistance. Antitumor effects of the newly conjugated compounds were compared to those of cisplatin. The data clearly indicate that improved drug efficiencies are achieved as a result of the intercalative moieties. The luminescent probe that was integrated in complexes 8-10 made it possible to monitor drug penetration using optical imaging. Enhanced targeting of tumor nuclei by the study compounds was confirmed by confocal microscopy. This paper describes a new class of platinum-based antitumorals differing from cisplatin in several critical aspects with the potential for significantly improving clinical outcomes in cancer patients.

Catalytic asymmetric cyclopropanation at a chiral platform.

Novel chiral Robson-type macrocyclic complexes M(2)-L [where M = Mn(II), Mn(III), Co(II) and Co(III) and L denotes tetra-Schiff base chiral ligands, L1 or L2] have been synthesized by metal template condensation of 2,6-diformyl-4-methyl-phenol, with 1R,2R-diaminocyclohexane (L1) or 1R,2R-diphenylethylenediamine (L2). The dinuclear Co(II) and Co(III) complexes catalyze asymmetric cyclopropanation of styrene with diazoacetate cooperatively and with high enantioselectivity.

Theoretical study of the influence of a heterogeneous activity distribution on intratumoral absorbed dose distribution.

Radioimmunotherapy of hematopoeitic cancers and micrometastases has been shown to have significant therapeutic benefit. The treatment of solid tumors with radionuclide therapy has been less successful. Previous investigations of intratumoral activity distribution and studies on intratumoral drug delivery suggest that a probable reason for the disappointing results in solid tumor treatment is nonuniform intratumoral distribution coupled with restricted intratumoral drug penetrance, thus inhibiting antineoplastic agents from reaching the tumor's center. This paper describes a nonuniform intratumoral activity distribution identified by limited radiolabeled tracer diffusion from tumor surface to tumor center. This activity was simulated using techniques that allowed the absorbed dose distributions to be estimated using different intratumoral diffusion capabilities and calculated for tumors of varying diameters. The influences of these absorbed dose distributions on solid tumor radionuclide therapy are also discussed. The absorbed dose distribution was calculated using the dose point kernel method that provided for the application of a three-dimensional (3D) convolution between a dose rate kernel function and an activity distribution function. These functions were incorporated into 3D matrices with voxels measuring 0.10 x 0.10 x 0.10 mm3. At this point fast Fourier transform (FFT) and multiplication in frequency domain followed by inverse FFT (iFFT) were used to effect this phase of the dose calculation process. The absorbed dose distribution for tumors of 1, 3, 5, 10, and 15 mm in diameter were studied. Using the therapeutic radionuclides of 131I, 186Re, 188Re, and 90Y, the total average dose, center dose, and surface dose for each of the different tumor diameters were reported. The absorbed dose in the nearby normal tissue was also evaluated. When the tumor diameters exceed 15 mm, a much lower tumor center dose is delivered compared with tumors between 3 and 5 mm in diameter. Based on these findings, the use of higher beta-energy radionuclides, such as 188Re and 90Y is more effective in delivering a higher absorbed dose to the tumor center at tumor diameters around 10 mm.

Novel chiral "calixsalen" macrocycle and chiral robson-type macrocyclic complexes.

A family of novel chiral "calixsalen" Schiff base macrocycles R,R-H(3)L4, R,R-H(3)L5, containing three chiral diamino moieties were synthesized by an efficient self-assembly and characterized by (1)H and (13)C NMR, mass spectrometry, and X-ray diffraction. The systematic synthesis, structure, and coordination properties of the [2 + 2] and [3 + 3] Robson-type Schiff base macrocyclic mono-, di-, tri-, and tetranuclear metal complexes were explored.