Targeted Transferrin-Modified Polymeric Micelles: Enhanced Efficacy in Vitro and in Vivo in Ovarian Carcinoma

In this study, transferrin (Tf)-modified poly­(ethylene glycol)-phosphatidylethanolamine (mPEG-PE) micelles loaded with the poorly water-soluble drug, R547 (a potent and selective ATP-competitive cyclin-dependent kinase (CDK) inhibitor), were prepared and evaluated for their targeting efficiency and cytotoxicity in vitro and in vivo to A2780 ovarian carcinoma cells, which overexpress transferrin receptors (TfR). At 10 mM lipid concentration, both Tf-modified and plain micelles solubilized 800 μg of R547. Tf-modified micelles showed enhanced interaction with A2780 ovarian carcinoma cells in vitro. The involvement of TfR in endocytosis of Tf-modified micelles was confirmed by colocalization studies of micelle-treated cells with the endosomal marker Tf-Alexa488. We confirmed endocytosis of micelles in an intact form with micelles loaded with a fluorescent dye and additionally labeled with fluorescent lipid. The in vitro cytotoxicity and in vivo tumor growth inhibition studies in A2780-tumor bearing mice confirmed the enhanced efficacy of Tf-modified R547-loaded micelles compared to free drug solution and to nonmodified micelles. The results of this study demonstrate the potential application of Tf-conjugated polymeric micelles in the treatment of tumors overexpressing TfR

Design, Synthesis, and Initial Biological Evaluation of a Steroidal Anti-Estrogen–Doxorubicin Bioconjugate for Targeting Estrogen Receptor-Positive Breast Cancer Cells

As part of our program to develop breast cancer specific therapeutic agents, we have synthesized a conjugate agent that is a conjugate of the steroidal anti-estrogen and the potent cytotoxin doxorubicin. In this effort, we employed a modular assembly approach to prepare a novel 11β-substituted steroidal anti-estrogen functionalized with an azido-tetraethylene glycol moiety, which could be coupled to a complementary doxorubicin benzoyl hydrazone functionalized with a propargyl tetraethylene glycol moiety. Huisgen [3 + 2] cycloaddition chemistry gave the final hybrid that was evaluated for selective uptake and cytotoxicity in ER­(+)-MCF-7 and ER(−)-MDA-MB-231 breast cancer cell lines. The results demonstrated that the presence of the anti-estrogenic component in the hybrid compound was critical for selectivity and cytotoxicity in ER­(+)-MCF-7 human breast cancer cells as the hybrid was ∼70-fold more potent than doxorubicin in inhibition of cell proliferation and promoting cell death

Periablational intratumoral doxorubicin accumulation for liposomal and micellar nanocarriers combined with RF ablation over time.

<p>*  = p<0.05 when compared to the other treatment group.</p

Gross and histopathologic outcomes for RFA/nanodrug combinations.

<p>*  = p<0.05 when compared to RF group.</p><p>** = P<0.05 when compared to adjuvant liposomal drug preparations.</p

Confocal tiled Imaging for fluorescent surface area quantitation in R3230 tumors sacrificed at 4 hours post RF (10×).

<p>R3230 tumors were treated with RF alone, followed by IV injection of equal volumes of 3 fluorescent beads of different colors and sizes (purple 20 nm, red 100 nm, green 500 nm). Quantitation of tiled images of tumor sections (center, periablational rim and tumor margin) demonstrated fluorescent bead accumulation in the periablational rim, with greatest uptake of 20 nm beads (<b>D</b>) followed by the 100 nm (<b>C</b>) beads followed by the 500 nm beads (<b>B</b>) (p<0.05, all comparisons).</p

Comparison of micellar and liposomal formulations on modulating local periablational target proteins (HIF-1α and HSP70) 24 hr after RF ablation of R3230 tumor.

<p>(<b>A</b>) Micellar doxorubicin suppressed periablational HIF-1α expression to a greater degree than (<b>B</b>) liposomal doxorubicin 24 hr after RF ablation (40×). Similarly, (<b>C</b>) micellar quercetin suppressed ablation-induced periablational HSP70 expression in R3230 tumor at 24 hr compared to (<b>D</b>) liposomal quercetin (10×).</p

Confocal Imaging of perivascular and interstitial fluorescent bead penetration in the periablational rim 24 hr after RF ablation of R3230 tumors (40×).

<p>R3230 tumors were treated with RF alone, followed by IV injection of 3 fluorescent beads of different colors and sizes (purple 20 nm, red 100 nm, green 500 nm). 40× images of the periablational rim reveal deeper penetration of the 20 nm beads into the intracellular spaces beyond the primary site of extravasation, outlining and mapping out the cells they are surrounding (<b>D,E</b>), whereas the majority of the 100 nm (<b>B</b>) remain confined to the primary site of extravasation. Even less extravasation is seen for the 500 nm beads (<b>C</b>).</p