Position of gadolinium atom(s) plays a key role in contrast enhancement of gadolinium-based contrast agents. To gain a better understanding of effects of distance of gadolinium in relation to the ...nanoconjugate platform, we designed and synthesized single- and multi-arm ("star") gadolinium conjugates equipped with antibody and peptides for targeting. The contrast agents were studied for their tumor imaging performance in a glioma mouse model.
Antibody- and peptide-targeted nano contrast agents (NCAs) were synthesized using polymalic acid platforms of different sizes. Gadolinium-DOTA and intermediates were attached as amides and targeting agents such as antibodies and peptides as thioethers. For in vivo experiments, we used human U87MG xenografts as glioma models. Magnetic resonance imaging (MRI) was performed on a Bruker BioSpec 94/20USR 9.4 T small-animal scanner. Delivery of contrast agents across the blood-brain barrier was studied by fluorescent microscopy.
All contrast agents accumulated into tumor and showed composition-dependent imaging performance. Peptide-targeted mini-NCAs had hydrodynamic diameters in the range 5.2-9.4 nm and antibody-targeted NCAs had diameters in the range 15.8-20.5 nm. Zeta potentials were in the range of -5.4--8.2 mV and -4.6--8.8 mV, respectively. NCAs showed superior relaxivities compared to MultiHance at 9.4 T. The signal enhancement indicated maximum accumulation in tumor 30-60 minutes after intravenous injection of the mouse tail vein. Only targeted NCAs were retained in tumor for up to 3 hours and displayed contrast enhancement.
The novel targeted NCAs with star-PEG features displayed improved relaxivity and greater contrast compared with commercial MultiHance contrast agent. The enhancement by mini-NCAs showed clearance of tumor contrast after 3 hours providing a suitable time window for tumor diagnosis in clinics. The technology provides a great tool with the promise of differential MRI diagnosis of brain tumors.
Laminins are the major constituents of blood vessel basement membranes (BMs). Each laminin is a trimer consisting of three assembled polypeptide chains, alpha, beta and gamma. More than 15 laminin ...isoforms are known to date and the expression of specific isoforms may change in certain pathological conditions. Here we show that during progression of glial tumors laminin-9 (alpha4beta2gamma1) is switched to laminin-8 (alpha4beta1gamma1), which is dramatically increased in glial brain tumors. Laminin-8 overproduction by glial tumor cells facilitates spread of glioma. Brain tumors with laminin-8 overexpression recur faster after standard treatment and patients have shorter survival time. Laminin-8 may be thus used as a predictor of tumor recurrence, patient survival and as a potential molecular target for glioma therapy.
Brain glioma treatment with checkpoint inhibitor antibodies to cytotoxic T-lymphocyte-associated antigen 4 (a-CTLA-4) and programmed cell death-1 (a-PD-1) was largely unsuccessful due to their ...inability to cross blood-brain barrier (BBB). Here we describe targeted nanoscale immunoconjugates (NICs) on natural biopolymer scaffold, poly(β-L-malic acid), with covalently attached a-CTLA-4 or a-PD-1 for systemic delivery across the BBB and activation of local brain anti-tumor immune response. NIC treatment of mice bearing intracranial GL261 glioblastoma (GBM) results in an increase of CD8+ T cells, NK cells and macrophages with a decrease of regulatory T cells (Tregs) in the brain tumor area. Survival of GBM-bearing mice treated with NIC combination is significantly longer compared to animals treated with single checkpoint inhibitor-bearing NICs or free a-CTLA-4 and a-PD-1. Our study demonstrates trans-BBB delivery of tumor-targeted polymer-conjugated checkpoint inhibitors as an effective GBM treatment via activation of both systemic and local privileged brain tumor immune response.
We have previously described decreased immunostaining of nidogen-1/entactin; laminin chains alpha1, alpha5, beta1,gamma1; and epithelial integrin alpha3beta1 in human diabetic retinopathy (DR) ...corneas. Here, using 142 human corneas, we tested whether these alterations might be caused by decreased gene expression levels or increased degradation. By semiquantitative reverse transcription-polymerase chain reaction, gene expression levels of the alpha1, alpha5, and beta1 laminin chains; nidogen-1/entactin; integrin alpha3 and beta1 chains in diabetic and DR corneal epithelium were similar to normal. Thus, the observed basement membrane and integrin changes were unlikely to occur because of a decreased synthesis. mRNA levels of matrix metalloproteinase-10 (MMP-10/stromelysin-2) were significantly elevated in DR corneal epithelium and stroma, and of MMP-3/stromelysin-1, in DR corneal stroma. No such elevation was seen in keratoconus corneas. These data were confirmed by immunostaining, zymography, and Western blotting. mRNA levels of five other proteinases and of three tissue inhibitors of MMPs were similar to normal in diabetic and DR corneal epithelium and stroma. The data suggest that alterations of laminins, nidogen-1/entactin, and epithelial integrin in DR corneas may occur because of an increased proteolytic degradation. MMP-10 overexpressed in the diabetic corneal epithelium seems to be the major contributor to the observed changes in DR corneas. Such alterations may bring about epithelial adhesive abnormalities clinically seen in diabetic corneas.
A new prototype of nanoconjugate, Polycefin, was synthesized for targeted delivery of antisense oligonucleotides and monoclonal antibodies to brain tumors. The macromolecular carrier contains: 1. ...biodegradable, nonimmunogenic, nontoxic β-poly(l-malic acid) of microbial origin; 2. Morpholino antisense oligonucleotides targeting laminin α4 and β1 chains of laminin-8, which is specifically overexpressed in glial brain tumors; 3. monoclonal anti-transferrin receptor antibody for specific tissue targeting; 4. oligonucleotide releasing disulfide units; 5. l-valine containing, pH-sensitive membrane disrupting unit(s), 6. protective poly(ethylene glycol); 7. a fluorescent dye (optional). Highly purified modules were conjugated directly with N-hydroxysuccinimidyl ester-activated β-poly(l-malic acid) at pendant carboxyl groups or at thiol containing spacers via thioether and disulfide bonds. Products were chemically validated by physical, chemical, and functional tests. In vitro experiments using two human glioma cell lines U87MG and T98G demonstrated that Polycefin was delivered into the tumor cells by a receptor-mediated endocytosis mechanism and was able to inhibit the synthesis of laminin-8 α4 and β1 chains at the same time. Inhibition of laminin-8 expression was in agreement with the designed endosomal membrane disruption and drug releasing activity. In vivo imaging showed the accumulation of intravenously injected Polycefin in brain tumor tissue via the antibody-targeted transferrin receptor-mediated endosomal pathway in addition to a less efficient mechanism known for high molecular mass biopolymers as enhanced permeability and retention effect. Polycefin was nontoxic to normal and tumor astrocytes in a wide range of concentrations, accumulated in brain tumor, and could be used for specific targeting of several biomarkers simultaneously.
After over a billion of vaccinations with messenger RNA-lipid nanoparticle (mRNA-LNP) based SARS-CoV-2 vaccines, anaphylaxis and other manifestations of hypersensitivity can be considered as very ...rare adverse events. Although current recommendations include avoiding a second dose in those with first-dose anaphylaxis, the underlying mechanisms are unknown; therefore, the risk of a future reaction cannot be predicted. Given how important new mRNA constructs will be to address the emergence of new viral variants and viruses, there is an urgent need for clinical approaches that would allow a safe repeated immunization of high-risk individuals and for reliable predictive tools of adverse reactions to mRNA vaccines. In many aspects, anaphylaxis symptoms experienced by the affected vaccine recipients resemble those of infusion reactions to nanomedicines. Here we share lessons learned over a decade of nanomedicine research and discuss the current knowledge about several factors that individually or collectively contribute to infusion reactions to nanomedicines. We aim to use this knowledge to inform the SARS-CoV-2 lipid-nanoparticle-based mRNA vaccine field.
To identify proteinases and growth factors abnormally expressed in human corneas of donors with diabetic retinopathy (DR), additional to previously described matrix metalloproteinase (MMP)-10 and -3 ...and insulin-like growth factor (IGF)-I.
RNA was isolated from 35 normal, diabetic, and DR autopsy human corneas ex vivo or after organ culture. Amplified cRNA was analyzed using 22,000-gene microarrays (Agilent Technologies, Palo Alto, CA). Gene expression in each diabetic corneal cRNA was assessed against pooled cRNA from 7 to 9 normal corneas. Select differentially expressed genes were validated by quantitative real-time RT-PCR (QPCR) and immunohistochemistry. Organ cultures were treated with a cathepsin inhibitor, cystatin C, or MMP-10.
More than 100 genes were upregulated and 2200 were downregulated in DR corneas. Expression of cathepsin F and hepatocyte growth factor (HGF) genes was increased in ex vivo and organ-cultured DR corneas compared with normal corneas. HGF receptor c-met, fibroblast growth factor (FGF)-3, its receptor FGFR3, tissue inhibitor of metalloproteinase (TIMP)-4, laminin alpha4 chain, and thymosin beta(4) genes were downregulated. The data were corroborated by QPCR and immunohistochemistry analyses; main changes of these components occurred in corneal epithelium. In organ-cultured DR corneas, cystatin C increased laminin-10 and integrin alpha(3)beta(1), whereas in normal corneas MMP-10 decreased laminin-10 and integrin alpha(3)beta(1) expression.
Elevated cathepsin F and the ability of its inhibitor to produce a more normal phenotype in diabetic corneas suggest increased proteolysis in these corneas. Proteinase changes may result from abnormalities of growth factors, such as HGF and FGF-3, in DR corneas. Specific modulation of proteinases and growth factors could reduce diabetic corneal epitheliopathy.
Novel genes specific for human oligodendroglioma and glioblastoma multiforme (GBM) were detected using the gene array analysis 18,376 genes Gene Discovery Array (GDA) from Incyte Genomics, Inc.. ...Eleven genes were chosen based on the highest ratios of differential expression identified by GDA between histologically normal adjacent tissue and brain tumor tissue. The differential expression of those 11 genes was verified by semiquantitative RT-PCR and Northern analysis on 22 samples of glial and other tumors of the brain, as well as of normal embryonic and adult brain tissue. Gene no. 5 (an EST) was more expressed by GDA analysis in histologically normal adjacent brain tissue than in the corresponding oligodendroglioma. By RT-PCR, this gene was expressed in a number of brain tumors but not in normal adult and embryonic brain. By GDA analysis, gene no. 7 (oligophrenin-1) gave the highest ratio compared to other genes in brain tissue adjacent to the GBM vs. GBM. By RT-PCR, oligophrenin-1 was expressed in tumors and tumor-adjacent tissue, whereas meningioma and corpus callosum were negative. Gene no. 11 (an EST) was expressed only in brain tumors but not in normal brain by Northern analysis (message size 1.5 kb) and RT-PCR. GDA analysis successfully identified genes preferentially expressed in brain tumors, which was confirmed by Northern analysis and semiquantitative RT-PCR. The validity of gene arrays for tumor-specific gene discovery is discussed. Study of differential gene expression in glial tumors should help identify the mechanism/s of transformation of normal glial cells to malignant.
Using gene array technology, we recently observed for the first time an up-regulation of laminin alpha4 chain in human gliomas. The data were validated by semiquantitative reverse transcription-PCR ...for RNA expression and immunohistochemistry for protein expression. Moreover, increase of the alpha4 chain-containing laminin-8 correlated with poor prognosis for patients with brain gliomas. Therefore, we hypothesized that inhibition of laminin-8 expression by a new generation of highly specific and stable antisense oligonucleotides (Morpholino) against chains of laminin-8 could slow or stop the spread of glioma and its recurrence and thus might be a promising approach for glioma therapy. We next sought to establish an in vitro model to test the feasibility of this approach and to optimize conditions for Morpholino treatment. To develop a model, we used human glioblastoma multiforme cell lines M059K and U-87MG cocultured with normal human brain microvascular endothelial cells (HBMVEC). Using Western blot analysis and immunohistochemistry, we confirmed that antisense treatment effectively blocked laminin-8 protein synthesis. Antisense oligonucleotides against both alpha4 and beta1 chains of laminin-8 were able to block significantly the invasion of cocultures through Matrigel. On average, the invasion was blocked by 62% in cocultures of U-87MG with HBMVEC and by 53% in cocultures of M059K with HBMVEC. The results show that laminin-8 may contribute to glioma progression and recurrence not only as part of the neovascularization process but also by directly increasing the invasive potential of tumor cells.
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