Sequences and biophysical data of peptides used in the study.

<p>^a<i>t</i>_R (min) denotes the retention time at 25°C by reversed-phase HPLC.</p><p>Sequences and biophysical data of peptides used in the study.</p

Peptide-induced cell apoptosis.

<p>(<b>A</b>) Mitochondrial membrane potential measured by JC-1, an indicator of mitochondrial function. HeLa cells were treated with various concentrations of HPRP-A1 or HPRP-A1-TAT for 24 h. (<b>B</b>) Percentage of early apoptotic cells, as assessed by flow cytometry. HeLa cells were treated with various concentrations of HPRP-A1 or HPRP-A1-TAT for 1 or 24 h. (<b>C</b>) Caspase-3, -8, and -9 activity. HeLa cells were treated with HPRP-A1 (4 μM) or HPRP-A1-TAT (4 μM) for 24 h before measuring caspase activity levels. Data are presented as the mean ± SD of three independent experiments.</p

Cellular uptake and interaction between peptides and cell membranes.

<p>(<b>A</b>) The fluorescence time profiles of interaction between peptides and membranes. HeLa cells were incubated with different concentrations of FITC-labeled HPRP-A1 and HPRP-A1-TAT at concentrations of 2, 4, and 8 μM. Images (400× magnification) were captured by laser scanning confocal microscopy every 30 s from 0 to 180 s. Green, FITC peptides; blue, 4,6-diamidino-2-phenylindile-stained nuclei. (<b>B</b>) LDH leakage assay. HeLa cells were incubated with HPRP-A1 and HPRP-A1-TAT at 2, 4, and 8 μM for 1 h and LDH assayed. (<b>C</b>) Cellular uptake of peptides, measured by flow cytometry. After incubation for 1 h at 4°C, HeLa cells were incubated with FITC-HPRP-A1 or FITC-HPRP-A1-TAT peptides for 1 h. The cells were those cultured and treated with peptides at 37°C were used as controls. Data are presented as the mean ± SD of three independent experiments. LDH, lactate dehydrogenase.</p

Circular dichroism spectra of peptides.

<p>(<b>A</b>) In benign medium (50 mM KH₂PO₄/K₂HPO₄ containing 100 mM KCl, pH 7.4) at 25°C and (<b>B</b>) in the presence of 50% TFE at 25°C. The symbols used are as follows: ■, HPRP-A1 peptide; ▲, HPRP-A1-TAT peptide.</p

The degradation of peptides by flow cytometry analysis.

<p>HeLa cells were incubated with FITC-labeled peptides (2, 4, or 8 μM) for 1 or 24 h. Cellular uptake of peptides is expressed as the median of cell fluorescence distribution by flow cytometry.</p

Anticancer (IC₅₀) and hemolytic activities (MHC) of peptides against cancer cells and human red blood cells.

<p>^aAnticancer activity (IC₅₀) represents the concentration of peptides at which cell viability was inhibited by 50% in comparison with the untreated cells. The MTT assay was repeated in triplicate, and IC₅₀ value was determined by averaging three repeated experiments.</p><p>^bGM of the anticancer activity (IC₅₀) for the four cancer cell lines.</p><p>^cHemolytic activity (MHC) was determined using human red blood cells after incubation with peptides for 1 h. If no hemolytic activity was observed at 500 μM, a value of 1000 μM was used for calculating the therapeutic index.</p><p>^dTherapeutic index = MHC/IC₅₀. Larger values indicate greater anticancer specificity.</p><p>GM, geometric mean; MHC, minimal hemolytic concentration.</p><p>Anticancer (IC₅₀) and hemolytic activities (MHC) of peptides against cancer cells and human red blood cells.</p