Light-Induced Hydrogel Based on Tumor-Targeting Mesoporous Silica Nanoparticles as a Theranostic Platform for Sustained Cancer Treatment

Herein, we report a facile fabrication of a polymer (azobenzene and α-cyclodextrin-functionalized hyaluronic acid) and gold nanobipyramids (AuNBs) conjugated mesoporous silica nanoparticles (MSNs) to be used as an injectable drug delivery system for sustained cancer treatment. Because of the specific affinity between the hyaluronic acid (HA) on MSNs and the CD44 antigen overexpressed on tumor cells, the MSNs can selectively attach to tumor cells. The nanocomposite material then exploits thermoresponsive interactions between α-cyclodextrin and azobenzene, and the photothermal properties of gold nanobipyramids, to in situ self-assemble into a hydrogel under near-infrared (NIR) radiation. Upon gelation, the drug (doxorubicin)-loaded MSNs carriers were enclosed in the HA network of the hydrogel, whereas further degradation of the HA in the hydrogel due to the upregulation of hyaluronidase (HAase) around the tumor tissue will result in the release of MSNs from the hydrogel, which can then be taken by tumor cells and deliver their drug to the cell nuclei. This design is able to provide a microenvironment with rich anticancer drugs in, and around, the tumor tissue for time periods long enough to prevent the recrudescence of the disease. The extra efficacy that this strategy affords builds upon the capabilities of conventional therapies

<i>Phytophthora sojae</i> Effector PsCRN70 Suppresses Plant Defenses in <i>Nicotiana benthamiana</i>

<div><p><i>Phytophthora sojae</i>, an oomycete pathogen, produces a large number of effector proteins that enter into host cells. The Crinklers (Crinkling and Necrosis, CRN) are cytoplasmic effectors that are conserved in oomycete pathogens and their encoding genes are highly expressed at the infective stages in <i>P. sojae</i>. However, their roles in pathogenesis are largely unknown. Here, we functionally characterized an effector <i>PsCRN70</i> by transiently and stably overexpressing it in <i>Nicotiana benthamiana</i>. We demonstrated that PsCRN70 was localized to the plant cell nucleus and suppressed cell death elicited by all the tested cell death-inducing proteins, including BAX, PsAvh241, PsCRN63, PsojNIP and R3a/Avr3a. Overexpression of the <i>PsCRN70</i> gene in <i>N. benthamiana</i> enhanced susceptibility to <i>P. parasitica</i>. The H₂O₂ accumulation in the <i>PsCRN70</i>-transgenic plants was reduced compared to the <i>GFP</i>-lines. The transcriptional levels of the defense-associated genes, including <i>PR1b</i>, <i>PR2b</i>, <i>ERF1</i> and <i>LOX</i>, were also down-regulated in the <i>PsCRN70</i>-transgenic lines. Our results suggest that PsCRN70 may function as a universal suppressor of the cell death induced by many elicitors, the host H₂O₂ accumulation and the expression of defense-associated genes, and therefore promotes pathogen infection.</p></div

Characterizations of the <i>PsCRN70-</i>transgenic <i>N. benthamiana</i>.

<p>A. RT-PCR analysis of <i>PsCRN70</i> expression in independent transgenic lines. #1, #3, #4 and #12, four independent T1 transgenic lines; P, <i>pBinGFP:PsCRN70</i> plasmid as a positive control; U, untransformed plant as a negative control. The upper panel represents the 624 bp fragment of <i>PsCRN70</i> gene and the lower panel represents the 100 bp fragment of <i>EF1α</i> gene as the control. B. Western blot analysis of expression of GFP: PsCRN70 fusion protein in transgenic <i>N. benthamiana</i> using monoclonal antibody against GFP. Subcellular localization of PsCRN70 in the transgenic <i>N. benthamiana</i> leaf tissues (C) and roots (D). The pictures were taken using a confocal microscope. The scale bar indicates 50 µm.</p

Suppression of the H₂O₂ accumulation in <i>N. benthamiana</i> by PsCRN70.

<p>A. DAB staining of the <i>P. parasitica</i>-inoculated <i>N. benthamiana</i> leaves. The H₂O₂ accumulation in the <i>PsCRN70</i>- and <i>GFP</i>- transgenic leaves were detected using DAB staining at 12 hpi. Photographs were taken after de-colorization of leaves with ethanol. B. The relative levels of DAB staining. The data were calculated by a combination of Photoshop and Quantity One for H₂O₂ accumulation in the indicated transgenic lines. The experiments were repeated three times in all transgenic lines with similar results. Four leaves were used for each treatment in each experiment. Bars represent the standard deviation (SD). Different letters at the top of the columns indicate significant differences (P<0.01, Duncan's multiple range test).</p

Down-regulation of the defense-associated genes in <i>N. benthamiana</i> by PsCRN70.

<p>A. Relative expression levels of the <i>PR1b</i>, <i>PR2b</i>, <i>ERF1</i> and <i>LOX</i> genes. The total RNA was extracted from the leaf tissues that transiently expressing <i>PsCRN70</i> and <i>GFP</i>, respectively, and the expression levels of the indicated genes were measured using qRT-PCR. B. Relative expression levels of the indicated genes in the stable transgenic <i>N. benthamiana</i>. The <i>N. benthamiana</i> leaves 36 hpi with <i>P. parasitica</i> zoospores were collected, and the gene expression levels were measured by qRT-PCR. The gene expression levels were normalized to the <i>EF1α</i> gene. Bars represent the standard deviation (SD), with significant difference (** for P<0.01 and * for P<0.05, Student's <i>t</i>-test).</p