Inhibition of programmed death 1 (PD-1), expressed on activated T cells, can break through immune resistance and elicit durable responses in human melanoma as well as other types of cancers. Canine ...oral malignant melanoma is one of the most aggressive tumors bearing poor prognosis due to its high metastatic potency. However, there are few effective treatments for the advanced stages of melanoma in veterinary medicine. Only one previous study indicated the potential of the immune checkpoint inhibitor, anti-canine PD-L1 therapeutic antibody in dogs, and no anti-canine PD-1 therapeutic antibodies are currently available. Here, we developed two therapeutic antibodies, rat-dog chimeric and caninized anti-canine PD-1 monoclonal antibodies and evaluated in vitro functionality for these antibodies. Moreover, we conducted a pilot study to determine their safety profiles and clinical efficacy in spontaneously occurring canine cancers. In conclusion, the anti-canine PD-1 monoclonal antibody was relatively safe and effective in dogs with advanced oral malignant melanoma and other cancers. Thus, our study suggests that PD-1 blockade may be an attractive treatment option in canine cancers.
Objectives
Canine oral squamous cell carcinoma (SCC) often develops in the gingiva and tonsils. The biological behavior of canine oral SCC is similar to that of human head and neck SCC (HNSCC). ...Inhibiting invasion and metastasis is major importance for the treatment of canine and human HNSCC. In this study, the significance of microRNA (miR)‐145 and Fascin1 (FSCN1) in the invasion of canine oral SCC was explored.
Materials and methods
Canine oral SCC tissues and cell lines were used for miR‐145 and FSCN1 expression analysis via real‐time PCR and immunohistochemistry. Canine oral SCC cell lines were used for in vitro assays.
Results
miR‐145 was downregulated while FSCN1 mRNA was upregulated in canine oral SCC. Immunohistochemistry revealed that FSCN1 was upregulated in SCC when compared to normal mucosa. Transfection of canine SCC cells with miR‐145 or FSCN1 siRNA suppressed cell growth and attenuated cell migration as well as invasion by inhibiting the epithelial‐to‐mesenchymal transition. Furthermore, the promoter region of miR‐145 was highly methylated in SCC cell lines and tissues.
Conclusion
The expression profile and functions of miR‐145 in canine oral SCC are similar to those in human HNSCC. Thus, canine oral SCC may represent a valuable preclinical model for human HNSCC.
Abstract MiR-34a was identified as one of the down-regulated micro-RNAs (miRs) in human colorectal cancer 5-fluorouracil (5-FU)-resistant DLD-1 cells compared with those in the parental DLD-1 cells. ...Exposure to 5-FU at 30 μM activated phosphoinositide 3-kinase (PI3K)/Akt signaling markedly from 12 h up to 48 h in the 5-FU-resistant cells compared with that in the parental cells and resulted in an overt difference in growth at those times. Furthermore, the expression of miR-34a in the 5-FU-resistant cells was sustained at a low-level, whereas it was up-regulated in the parental cells after the 5-FU treatment. Sirt1 , which is one of the target genes for miR-34a and related to drug-resistance, was strikingly up-regulated in the 5-FU-resistant cells. The ectopic expression of miR-34a in the 5-FU-resistant cells inhibited growth, as in the parental cells, and attenuated the resistance to 5-FU through the down-regulation of Sirt1 and E2F3. Moreover, the silencing of Sirt1 significantly canceled the resistance to 5-FU in the 5-FU-resistant cells. These findings suggest that miR-34a targeting the Sirt1 and E2F3 genes could negatively regulate, at least in part, the resistance to 5-FU in human colorectal cancer DLD-1 cells.
Much evidence indicates that various naturally occurring compounds have an anti-cancer effect, but the detailed mechanisms are not well understood. In this study, we selected anti-cancer ...phytochemicals such as epigallocatechin-3-gallate (EGCG), resveratrol (RES) and α-mangostin (α-M), all of which are well-characterized chemopreventive agents. We sought to elucidate the mechanism of their anti-cancer effects and the synergistic effects obtained by combined treatment with the anti-cancer drug 5-fluorouracil (5-FU) in three human colon cancer cell lines. The numbers of viable cells were consistently decreased by the treatment with EGCG, RES or α-M at more than 10 μM in all three cell lines tested. All compounds mainly induced apoptosis and suppressed the PI3K/Akt signaling pathway. Additionally, α-M, which had the greatest PI3K/Akt-suppressing activity, also suppressed MAP kinase (MAPK)/Erk1/2 signaling. Importantly, the combination treatment with RES and 5-FU induced a remarkably synergistic enhancement of growth inhibition and apoptosis through the additional suppression of the MAPK/Erk1/2 signaling pathway in colon cancer DLD-1 cells. Interestingly, RES increased the intracellular expression level of miR-34a, which down-regulated the target gene E2F3 and its downstream Sirt1, resulting in growth inhibition. These findings indicate that these compounds functioned as chemosensitizers when combined with anti-cancer drugs through the modulation of apoptotic and growth-related signaling pathways. Also, RES exerted its anti-cancer activity in part through a newly defined mechanism, i.e., the miR-34a/E2F3/Sirt1 cascade.
Objective
Squamous cell carcinoma (SCC) occurring in the tonsils (TSCC) has a poorer prognosis than SCC occurring in other regions of the oral cavity (non-tonsillar SCC NTSCC) because it easily ...metastasizes to distant organs. This study aimed to elucidate the molecular mechanisms underlying the migration and invasion of TSCC cells
in vitro
.
Materials and methods
This study focused on differential microRNA (miRNA) expression using microRNA microarrays and quantitative polymerase chain reaction in canine TSCC and NTSCC tissues and cell lines. A target gene of the miRNA involved in cell migration and invasion was validated by wound healing, transwell, and luciferase assays.
Results
miR-203 expression was lower in TSCC tissues than in the normal oral mucosa and NTSCC tissues. Transfection of the miR-203 mimic resulted in the downregulation of mesenchymal marker protein expression and attenuation of cell migration and invasion in TSCC cells, but not in NTSCC cells. A dual-luciferase assay revealed that miR-203 directly targeted the mesenchymal transcription factor
SLUG
. SLUG overexpression enhances the migration of TSCC cells.
Conclusion
Our study indicates that the miR-203/SLUG axis may be involved in the metastatic mechanisms of TSCC.
Recent research has focused on immunotherapy, particularly with regard to cancer treatment. Programmed death-1 and programmed death ligand 1 (PD-1/PD-L1) pathway blockade is a central topic of the ...promising immunotherapy field. In veterinary medicine, observations of the PD-1/PD-L1 pathway, including the relationship between immune cells and diseases, have increased. In this study, monoclonal antibodies specific to canine PD-1 and PD-L1 were developed, and the antibodies against PD-1 and PD-L1 bind to PD-1 and PD-L1 overexpressing cells, respectively. Additionally, each antibody interfered with the interaction between PD-1 and PD-L1. The expression of PD-1 and PD-L1 was detected on activated T cells from canine peripheral blood mononuclear cells (PBMC), and, remarkably, was the first recorded instance of PD-L1 expression on canine immature dendritic cells. Production of IFN-γ by activated T cells increased significantly when incubated with anti-PD-1 antibody alone and with both anti-PD-1 and anti-PD-L1 antibodies, revealing the functional effects of the antibodies. The antibodies will be useful for research on immune systems and may be the first passive immunotherapy approach in canine cancer patients.
To highlight the impact of satellite measurements, a comparison between the Japanese 55‐year reanalysis (JRA‐55) and its equivalent without the assimilation of satellite observations (JRA‐55C; C ...stands for ‘conventional’ observations) was conducted. As an illustrative example of the detectability problem of extreme events, we report on the reproducibility of a stratospheric sudden warming (SSW) event that occurred in late September 2002; this event represents the first observed unique vortex splitting event in the Antarctic stratosphere. Through the data assimilation system of JRA‐55, the initial tendency of this warming event and the following recovery process were well captured even when no satellite observations were used. However, the warming in JRA‐55C does not satisfy the criteria for a major SSW event besides the lack of splitting behaviour in the polar vortex. A prominent difference between JRA‐55 and JRA‐55C during the SSW event, which was characterized by the sudden appearance of a nearly barotropic structure from the upper stratosphere to the troposphere, was found over the Western Hemisphere reflecting the geographic distribution of observational sites. Moreover, several differences in the precursory state of the polar vortex and the observational anchoring effect are consistent with the proposal that this SSW was caused by the catastrophic breakdown of a highly deformed polar vortex as suggested by some recent works.
The figure shows the shape of the stratospheric polar vortex on 24 September 2002 in two reanalysis products according to Ertel's potential vorticity at the 850 K isentropic surface. The historical vortex splitting event in the Southern Hemisphere captured by full observations (a) was not reproduced in the reanalysis assimilating in situ observations only (b). Thus, this example highlights and reminds us of the importance of satellite observations to avoid missing extreme atmospheric phenomena.
Dog spontaneously develop prostate cancer (PC) like humans. Because most dogs with PC have a poor prognosis, they could be used as a translational model for advanced PC in humans. Stem cell‐derived ...3‐D organoid culture could recapitulate organ structures and physiology. Using patient tissues, a human PC organoid culture system was established. Recent study has shown that urine cells also possess the characteristic of stem cells. However, urine cell‐derived PC organoids have never been produced. Therefore, we generated PC organoids using the dog urine samples. Urine organoids were successfully generated from each dog with PC. Each organoid showed cystic structures and resembled the epithelial structures of original tissues. Expression of an epithelial cell marker, E‐cadherin, and a myofibloblast marker, α‐SMA, was observed in the urine organoids. The organoids also expressed a basal cell marker, CK5, and a luminal cell marker, CK8. CD49f‐sorted basal cell organoids rapidly grew compared with CD24‐sorted luminal cell organoids. The population of CD44‐positive cells was the highest in both organoids and the original urine cells. Tumors were successfully formed with the injection of the organoids into immunodeficient mice. Treatment with a microtubule inhibitor, docetaxel, but not a cyclooxygenase inhibitor, piroxicam, and an mTOR inhibitor, rapamycin, decreased the cell viability of organoids. Treatment with a Hedgehog signal inhibitor, GANT61, increased the radiosensitivity in the organoids. These findings revealed that PC organoids using urine might become a useful tool for investigating the mechanisms of the pathogenesis and treatment of PC in dogs.
In the present study, we for the first time generated the dog prostate cancer organoids using the urine samples. Our results suggest urine sample‐derived organoid culture system contributes to the treatment of not only dog prostate cancer but also human advanced prostate cancer.
Canine hemangiosarcoma (HSA) is a commonly occurring aggressive tumor stemming from the vascular endothelial cells and is considered to be a good model for a similar disease in humans, called ...angiosarcoma. In this study, we reviewed drug libraries to identify new signal transduction inhibitors that can suppress the cell growth of canine HSA in vitro. We observed that tenovin-6, a sirtuin (SIRT) inhibitor, inhibited cell proliferation and induced cell death in three canine HSA cell lines (JuB4, Re12, and Ud6). These effects were induced through G1 cell cycle arrest and caspase-3 activation. Although tenovin-6 is known as an inhibitor of SIRT1 and SIRT2, knockout (KO) of genes encoding SIRT1 and/or SIRT2 had no apparent impact on cell proliferation in canine HSA. In addition, tenovin-6 showed cell growth inhibition in SIRT KO cells, as well as parental cells. These results indicated the cytotoxicity of tenovin-6 was a SIRT-independent event. Instead, we found that tenovin-6 inhibited autophagy flux in canine HSA cells, as evidenced by the suppression of lysosomal proteolysis. These results suggested that tenovin-6 induces cell growth suppression in canine HSA cells by impairing the lysosomal function. Therefore, tenovin-6 could be used in a new therapeutic strategy to treat canine HSA.
•By the drug screening, we found that tenovin-6 inhibited the proliferation of canine hemangiosarcoma cell lines.•Tenovin-6 inhibited tumor cell growth with caspase-3 activation and G1 cell cycle arrest, but SIRT-independent pathway.•Tenovin-6 inhibits the autophagy flux by suppressing the lysosomal activity.
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