KLK4 Induces Anti-Tumor Effects in Human Xenograft Mouse Models of Orthotopic and Metastatic Prostate Cancer.

Recent reports have suggested the role of kallikrein-related peptidase 4 (KLK4) to be that of remodeling the tumor microenvironment in many cancers, including prostate cancer. Notably, these studies have suggested a pro-tumorigenic role for KLK4, especially in prostate cancer. However, these have been primarily in vitro studies, with limited in vivo studies performed to date. Herein, we employed an orthotopic inoculation xenograft model to mimic the growth of primary tumors, and an intracardiac injection to induce metastatic dissemination to determine the in vivo tumorigenic effects of KLK4 overexpressed in PC3 prostate cancer cells. Notably, we found that these KLK4-expressing cells gave rise to smaller localized tumors and decreased metastases than the parent PC-3 cells. To our knowledge, this is the first report of an anti-tumorigenic effect of KLK4, particularly in prostate cancer. These findings also provide a cautionary tale of the need for in vivo analyses to substantiate in vitro experimental data.

Thermostable small-molecule inhibitor of angiogenesis and vascular permeability that suppresses a pERK-FosB/ΔFosB-VCAM-1 axis.

Vascular permeability and angiogenesis underpin neovascular age-related macular degeneration and diabetic retinopathy. While anti-VEGF therapies are widely used clinically, many patients do not respond optimally, or at all, and small-molecule therapies are lacking. Here, we identified a dibenzoxazepinone BT2 that inhibits endothelial cell proliferation, migration, wound repair in vitro, network formation, and angiogenesis in mice bearing Matrigel plugs. BT2 interacts with MEK1 and inhibits ERK phosphorylation and the expression of FosB/ΔFosB, VCAM-1, and many genes involved in proliferation, migration, angiogenesis, and inflammation. BT2 reduced retinal vascular leakage following rat choroidal laser trauma and rabbit intravitreal VEGF-A165 administration. BT2 suppressed retinal CD31, pERK, VCAM-1, and VEGF-A165 expression. BT2 reduced retinal leakage in rats at least as effectively as aflibercept, a first-line therapy for nAMD/DR. BT2 withstands boiling or autoclaving and several months' storage at 22°C. BT2 is a new small-molecule inhibitor of vascular permeability and angiogenesis.

Targeted beta therapy of prostate cancer with 177Lu-labelled Miltuximab® antibody against glypican-1 (GPC-1).

PURPOSE: Chimeric antibody Miltuximab®, a human IgG1 engineered from the parent antibody MIL-38, is in clinical development for solid tumour therapy. Miltuximab® targets glypican-1 (GPC-1), a cell surface protein involved in tumour growth, which is overexpressed in solid tumours, including prostate cancer (PCa). This study investigated the potential of 89Zr-labelled Miltuximab® as an imaging agent, and 177Lu-labelled Miltuximab® as a targeted beta therapy, in a mouse xenograft model of human prostate cancer. METHODS: Male BALB/c nude mice were inoculated subcutaneously with GPC-1-positive DU-145 PCa cells. In imaging and biodistribution studies, mice bearing palpable tumours received (a) 2.62 MBq [89Zr]Zr-DFO-Miltuximab® followed by PET-CT imaging, or (b) 6 MBq [177Lu]Lu-DOTA-Miltuximab® by Cerenkov imaging, and ex vivo assessment of biodistribution. In an initial tumour efficacy study, mice bearing DU-145 tumours were administered intravenously with 6 MBq [177Lu]Lu-DOTA-Miltuximab® or control DOTA-Miltuximab® then euthanised after 27 days. In a subsequent survival efficacy study, tumour-bearing mice were given 3 or 10 MBq of [177Lu]Lu-DOTA-Miltuximab®, or control, and followed up to 120 days. RESULTS: Antibody accumulation in DU-145 xenografts was detected by PET-CT imaging using [89Zr]Zr-DFO-Miltuximab® and confirmed by Cerenkov luminescence imaging post injection of [177Lu]Lu-DOTA-Miltuximab®. Antibody accumulation was higher (% IA/g) in tumours than other organs across multiple time points. A single injection with 6 MBq of [177Lu]Lu-DOTA-Miltuximab® significantly inhibited tumour growth as compared with DOTA-Miltuximab® (control). In the survival study, mice treated with 10 MBq [177Lu]Lu-DOTA-Miltuximab® had significantly prolonged survival (mean 85 days) versus control (45 days), an effect associated with increased cancer cell apoptosis. Tissue histopathology assessment showed no abnormalities associated with [177Lu]Lu-DOTA-Miltuximab®, in line with other observations of tolerability, including body weight stability. CONCLUSION: These findings demonstrate the potential utility of Miltuximab® as a PET imaging agent ([89Zr]Zr-DFO-Miltuximab®) and a beta therapy ([177Lu]Lu-DOTA-Miltuximab®) in patients with PCa or other GPC-1 expressing tumours.

Low-power laser irradiation inhibits arecoline-induced fibrosis: an in vitro study.

Oral submucous fibrosis (OSF) is a potentially malignant disorder that is characterized by a progressive fibrosis in the oral submucosa. Arecoline, an alkaloid compound of the areca nut, is reported to be a major aetiological factor in the development of OSF. Low-power laser irradiation (LPLI) has been reported to be beneficial in fibrosis prevention in different damaged organs. The aim of this study was to investigate the potential therapeutic effects of LPLI on arecoline-induced fibrosis. Arecoline-stimulated human gingival fibroblasts (HGFs) were treated with or without LPLI. The expression levels of the fibrotic marker genes alpha-smooth muscle actin (α-SMA) and connective tissue growth factor (CTGF/CCN2) were analysed by quantitative real-time reverse transcription polymerase chain reaction (RT-PCR) and western blots. In addition, the transcriptional activity of CCN2 was further determined by a reporter assay. The results indicated that arecoline increased the messenger RNA and protein expression of CCN2 and α-SMA in HGF. Interestingly, both LPLI and forskolin, an adenylyl cyclase activator, reduced the expression of arecoline-mediated fibrotic marker genes and inhibited the transcriptional activity of CCN2. Moreover, pretreatment with SQ22536, an adenylyl cyclase inhibitor, blocked LPLI's inhibition of the expression of arecoline-mediated fibrotic marker genes. Our data suggest that LPLI may inhibit the expression of arecoline-mediated fibrotic marker genes via the cAMP signalling pathway.

Evaluation of Polymeric Nanomedicines Targeted to PSMA: Effect of Ligand on Targeting Efficiency.

Targeted nanomedicines offer a strategy for greatly enhancing accumulation of a therapeutic within a specific tissue in animals. In this study, we report on the comparative targeting efficiency toward prostate-specific membrane antigen (PSMA) of a number of different ligands that are covalently attached by the same chemistry to a polymeric nanocarrier. The targeting ligands included a small molecule (glutamate urea), a peptide ligand, and a monoclonal antibody (J591). A hyperbranched polymer (HBP) was utilized as the nanocarrier and contained a fluorophore for tracking/analysis, whereas the pendant functional chain-ends provided a handle for ligand conjugation. Targeting efficiency of each ligand was assessed in vitro using flow cytometry and confocal microscopy to compare degree of binding and internalization of the HBPs by human prostate cancer (PCa) cell lines with different PSMA expression status (PC3-PIP (PSMA+) and PC3-FLU (PSMA-). The peptide ligand was further investigated in vivo, in which BALB/c nude mice bearing subcutaneous PC3-PIP and PC3-FLU PCa tumors were injected intravenously with the HBP-peptide conjugate and assessed by fluorescence imaging. Enhanced accumulation in the tumor tissue of PC3-PIP compared to PC3-FLU highlighted the applicability of this system as a future imaging and therapeutic delivery vehicle.