The effect of maternal nicotine exposure on downstream caspase-mediated apoptotic pathways.

<p>Protein levels of targets of interest were determined via Western blot. <b>(A)</b> Specific targeted protein bands as detected by respective antibodies via Western blot. <b>(B)</b> Cleaved caspase-3 protein levels. <b>(C)</b> Cleaved caspase-6 protein levels. <b>(D)</b> Cleaved caspase-7 protein levels. <b>(E)</b> Cleaved Lamin A protein levels. All protein levels were expressed as means normalized to β-Actin ± SEM (n = 5-6/group).</p

Proposed schematic of the effect of nicotine on ER stress and the unfolded protein response in the e15 placenta.

<p>Pathways affected by nicotine are indicated by the darkened arrows and boxes. In summary, nicotine exposure was shown to augment ER stress and activate the unfolded protein response in the e15 placenta. Activation was most prominent in the PERK branch and was demonstrated in association with impaired disulfide bond formation. Nicotine is proposed to impair disulfide bond formation through direct or indirect down-regulation of PDI and other oxidoreductases. Disulfide bond formation is further impaired through increased hypoxia as caused by nicotine-induced vasoconstriction. Additionally, up-regulation of GCN2 suggests amino acid starvation and activation of the integrated stress response to further phosphorylate eIF2α. However, the lack of Bax and caspase activation seen at e15 suggests that the nicotine-induced ER stress response may possibly be attempting to avoid apoptosis by re-establishing some manner of sub-optimal placental homeostasis to adapt to the ER stress experienced.</p

The effect of maternal nicotine exposure on downstream CHOP-mediated apoptotic pathways.

<p>Protein and mRNA levels of targets of interest were determined via Western blot and RT-PCR, respectively. <b>(A)</b> Specific targeted protein bands as detected by respective antibodies via Western blot. <b>(B)</b> mRNA levels of Bax, Bcl-2, and ratio of Bax: Bcl-2. <b>(C)</b> Protein levels of Bax, Bcl-2, and ratio of Bax: Bcl-2. All protein levels were expressed as means normalized to β-Actin ± SEM (n = 5-6/group). All mRNA levels were expressed as means normalized to the geometric mean of three stable housekeeping genes (β-Actin, 18S, and Gapdh) ± SEM (n = 5-6/group).</p

Overcoming drug resistance by codelivery of Dox and PTX via cMLVs (D: Dox; T: PTX).

<p>(A, B) <i>In vitro</i> cytotoxicity of cMLV(single drug) and cMLV(drug combinations) in B16 melanoma tumor cells (A) and 4T1 breast tumor cells (B). (C, D, E) <i>In vitro</i> cytotoxicity of cMLV(single drug) and cMLV(drug combinations) in drug-resistant JC cells (C), B16-R cells (D) and 4T1-R cells (E). IIP_Cmax was determined by incorporating three parameters (IC₅₀, <i>D</i> and m) in the median effect model into the following equation: IIP_Cmax  = log (1+(Cmax/IC₅₀)^m). Data are represented as mean ± SD (n = 3). Asterisks indicate statistical significance between two groups (*<i>P</i> < 0.05, **<i>P</i> < 0.01).</p

Nicotine exposure leads to activation of downstream targets in the PERK branch of the unfolded protein response in e15 rat placentas.

<p>Protein and mRNA levels of targets of interest were determined via Western blot and RT-PCR, respectively. <b>(A)</b> Specific targeted protein bands as detected by respective antibodies via Western blot. <b>(B)</b> Atf4 mRNA levels. <b>(C)</b> Atf4 protein levels. <b>(D)</b> Grp78 mRNA levels. <b>(E)</b> Grp78 protein levels. <b>(F)</b> CHOP mRNA levels. <b>(G)</b> CHOP protein levels. All protein levels were expressed as means normalized to β-Actin ± SEM (n = 5-6/group). All mRNA levels were expressed as means normalized to the geometric mean of three stable housekeeping genes (β-Actin, 18S, and Gapdh) ± SEM (n = 5-6/group).*, Significant difference (p < 0.05). **, Significant difference (p<0.01).</p

Effect of codelivered cMLVs on P-gp expression in tumors.

<p>(A, B) Mice bearing 4T1 tumor (A) and multidrug-resistant tumor JC (B) were injected intravenously through the tail vein with cMLV (5 mg/kg Dox), cMLV (5 mg/kg PTX), 5 mg/kg Dox + 5 mg/kg PTX, or cMLV (5 mg/kg Dox+5 mg/kg PTX). Three days after injection, tumors were excised, and stained by P-gp-specific antibody (green), followed by nuclear costaining with DAPI (blue). Scale bar represents 50 µm. (C, D) Quantification of P-gp-positive cells in 4T1 (C) and JC (D) tumors. To quantify P-gp-positive cells, 4 regions of interest (ROI) were randomly chosen per image at ×2 magnification. Within one region, area of P-gp-positive nuclei and area of nuclear staining were counted. The data are expressed as % total nuclear area that is P-gp-positive in the region. Data are represented as mean ± SD (n = 3).</p

Western Blot secondary antibodies, dilutions used in experiments, and company and catalogue information.

<p>Western Blot secondary antibodies, dilutions used in experiments, and company and catalogue information.</p

Nicotine-induced vasoconstriction leads to both hypoxia and reduced amino acid supply in e15 placenta.

<p>Protein levels of targets of interest were determined via Western blot. <b>(A)</b> Specific targeted protein bands as detected by respective antibodies via Western blot. <b>(B)</b> Hif1α protein levels. <b>(C)</b> GCN2 protein levels. All protein levels were expressed as means normalized to β-Actin ± SEM (n = 5-6/group). *, Significant difference (p<0.05). **, Significant difference (p<0.01).</p

Nicotine decreases PDI expression in e15 rat placentas.

<p>Protein levels of targets of interest were determined via Western blot. <b>(A)</b> Specific targeted protein bands as detected by respective antibodies via Western blot. <b>(B)</b> PDI protein levels. <b>(C)</b> Ero1-Lα protein levels. All protein levels were expressed as means normalized to β-Actin ± SEM (n = 5-6/group). *, Significant difference (p<0.05).</p

The effect of maternal nicotine exposure on various ER oxidoreductases in e15 rat placentas.

<p>Protein and mRNA levels of targets of interest were determined via Western blot and RT-PCR, respectively. <b>(A)</b> Specific targeted protein bands as detected by respective antibodies via Western blot. <b>(B)</b> GPx-7 mRNA levels. <b>(C)</b> GPx-7 protein levels. <b>(D)</b> VKORC1 mRNA levels. <b>(E)</b> VKORC1 protein levels. <b>(F)</b> QSOX1 mRNA levels. <b>(G)</b> QSOX1 protein levels. All protein levels were expressed as means normalized to β-Actin ± SEM (n = 5-6/group). All mRNA levels were expressed as means normalized to the geometric mean of three stable housekeeping genes (β-Actin, 18S, and Gapdh) ± SEM (n = 5-6/group). *, Significant difference (p<0.05).</p