Successful endovascular embolization of the common hepatic artery for pseudoaneurysm associated with pancreatic fistula after liver transplantation: a case report.

BACKGROUND: After orthotopic liver transplantation (OLT), complications such as hepatic artery stenosis, thrombosis, and bleeding are possible. Hepatic artery pseudoaneurysms (HAP) are prone to rupture, rupture hemorrhage, and increased mortality risk. Endovascular treatment of HAP may result in recurrence, even after successful embolization with thrombin. Formation of a HAP in the common hepatic artery (CHA) is challenging because the CHA is the only artery in the liver graft after OLT. Therefore, CHA embolization in HAP is not an initial option. We report a case of HAP at the CHA after OLT that was treated with endovascular therapy, resulting in the occlusion of the CHA with coil embolization, achieving a radical cure. CASE PRESENTATION: A 59-year-old man with decompensated hepatitis C virus cirrhosis underwent deceased donor whole-liver transplantation after graft failure of a living donor liver transplantation. After the second transplantation, the patient developed infectious narrow-necked HAP at the CHA associated with postoperative pancreatic fistula. Repeated transcatheter arterial embolization with thrombin and n-butyl-2-cyanoacrylate was unsuccessful, as confirmed by postprocedure angiography, which revealed recanalization and regrowth of the HAP. Eight months after the first transcatheter arterial embolization, the patient presented with a chief complaint of abdominal pain due to an enlarged HAP. Angiography of the superior mesenteric artery (SMA) revealed a collateral bypass around the bile duct from the SMA to the liver graft. Coil embolization of the HAP in the CHA completely occluded the HAP without complications. More than 2 years after coil embolization, the liver graft function test results remained within normal limits without HAP recurrence. CONCLUSIONS: HAP at the CHA after liver transplantation can be fatal if ruptured. Because the liver is a highly angiogenic organ, even if initial treatment is not successful, radical treatment to occlude the CHA with HAP is possible if sufficient collateral vessels are developed.

Macrophage activity at the site of tumor ablation can promote murine urothelial cancer via transforming growth factor-ß1.

Cell death and injury at the site of tumor ablation attracts macrophages. We sought to understand the status and activity of these cells while focusing on transforming growth factor-ß1 (TGF-ß1), a potent immunosuppressive and tumorigenic cytokine. Patients with urothelial cancer who underwent ablation using electrocautery or laser demonstrated increased infiltration and numbers of CD8+ T cells, along with FoxP3+ regulatory T cells, CD68+ macrophages and elevated levels of TGF-ß1 in recurrent tumors. Similar findings were reproduced in a mouse model of urothelial cancer (MB49) by partial tumor ablation with irreversible electroporation (IRE). Stimulation of bone marrow derived macrophages with MB49 cell debris produced using IRE elicited strong M2 polarization, with exuberant secretion of TGF-ß1. The motility, phenotypic markers and cytokine secretion by macrophages could be muted by treatment with Pirfenidone (PFD), a clinically approved drug targeting TGF-ß1 signaling. MB49 cancer cells exposed to TGF-ß1 exhibited increased migration, invasiveness and upregulation of epithelial-mesenchymal transition markers α-Smooth Muscle Actin and Vimentin. Such changes in MB49 cells were reduced by treatment with PFD even during stimulation with TGF-ß1. IRE alone yielded better local tumor control when compared with control or PFD alone, while also reducing the overall number of lung metastases. Adjuvant PFD treatment did not provide additional benefit under in vivo conditions.

Acute ATP loss during irreversible electroporation mediates caspase independent cell death.

Irreversible electroporation (IRE) has been reported to variably cause apoptosis, necrosis, oncosis or pyroptosis. Intracellular ATP is a key substrate for apoptosis which is rapidly depleted during IRE, we sought to understand whether intracellular ATP levels is a determinant of the mode of cell death following IRE. A mouse bladder cancer cell line (MB49) was treated with electric fields while increasing the number of pulses at a fixed electric field strength, and pulse width. Cell proliferation and viability and ATP levels were measured at different timepoints post-treatment. Cell death was quantified with Annexin-V/Propidium Iodide staining. Caspase activity was measure with a fluorometric kit and western blotting. A pan-caspase (Z-VAD-FMK) inhibitor was used to assess the impact of signal inhibition. We found cell death following IRE was insensitive to caspase inhibition and was correlated with ATP loss. These findings were confirmed by cell death assays and measurement of changes in caspase expression on immunoblotting. This effect could not be rescued by ATP supplementation. Rapid and acute ATP loss during IRE interferes with caspase signaling, promoting necrosis. Cell necrosis from IRE is expected to be immunostimulatory and may be effective in cancer cells that carry mutated or defective apoptosis genes.

Expanding the role of interventional oncology for advancing precision immunotherapy of solid tumors.

Adoptive cell therapy with chimeric antigen receptors (CAR) T cells has proven effective for hematologic malignancies, but success in solid tumors has been impeded by poor intratumoral infiltration, exhaustion of effector cells from antigen burden, and an immunosuppressive tumor microenvironment. Results from recent clinical trials and preclinical studies lend promising evidence of locoregional approaches for CAR T cell delivery, priming the tumor microenvironment, and performing adjuvant therapies that sustain T cell activity. Interventional oncology is a subspeciality of interventional radiology where imaging guidance is used to perform percutaneous and catheter-directed procedures for localized, non-surgical therapy or interrogation of solid tumors. Interventional oncology provides unique synergies with immunotherapy, which has been well-studied to improve treatment efficacy while reducing toxicities associated with systemic treatment. Besides aiding in CAR T cell delivery, priming, or the stimulation of the tumor microenvironment to promote effector survival and function, interventional oncology can also aid in the monitoring of treatment response through selective, multiplex tumor sampling and catheter-based venous sampling. This review presents an overview of interventional oncology, its various procedures, and its potential for advancing CAR T cell immunotherapy of solid tumors.

Lung Ablation with Irreversible Electroporation Promotes Immune Cell Infiltration by Sparing Extracellular Matrix Proteins and Vasculature: Implications for Immunotherapy.

Background: This study investigated the sparing of the extracellular matrix (ECM) and blood vessels at the site of lung irreversible electroporation (IRE), and its impact on postablation T cell and macrophage populations. Materials and Methods: Normal swine (n = 8) lung was treated with either IRE or microwave ablation (MWA), followed by sacrifice at 2 and 28 days (four animals/timepoint) after treatment. En bloc samples of ablated lung were stained for blood vessels (CD31), ECM proteins (Collagen, Heparan sulfate, and Decorin), T cells (CD3), and macrophages (Iba1). Stained slides were analyzed with an image processing software (ImageJ) to count the number of positive staining cells or the percentage area of tissue staining for ECM markers, and the statistical difference was evaluated with Student's t-test. Results: Approximately 50% of the blood vessels and collagen typically seen in healthy lung were evident in IRE treated samples at Day 2, with complete destruction within MWA treated lung. These levels increased threefold by Day 28, indicative of post-IRE tissue remodeling and regeneration. Decorin and Heparan sulfate levels were reduced, and it remained so through the duration of observation. Concurrently, numbers of CD3+ T cells and macrophages were not different from healthy lung at Day 2 after IRE, subsequently increasing by 2.5 and 1.5-fold by Day 28. Similar findings were restricted to the peripheral inflammatory rim of MWA samples, wherein the central necrotic regions remained acellular through Day 28. Conclusion: Acute preservation of blood vessels and major ECM components was observed in IRE treated lung at acute time points, and it was associated with the increased infiltration and presence of T cells and macrophages, features that were spatially restricted in MWA treated lung.

The effect of synthetic bone graft substitutes on bone formation in rabbit calvarial defects.

The aim of this study was to evaluate the influence of the intensity of the biomimetic hydroxyapatite (HA) coating of α-tricalcium phosphate (α-TCP) on biomaterial degradation and bone formation. Twenty-four female NZW rabbits of approximately 12 weeks of age were used. Critical size defects were randomly treated with 3%:97% HA:α-TCP (BBCP1), 12%:88% HA:α-TCP (BBCP2), and 23%:77% HA:α-TCP (BBCP3), respectively or sham. All defects were covered with a resorbable collagen membrane. Animals were euthanized after 3 and 12 weeks of healing and samples were investigated by micro-CT and histologic analysis. Ingrowth of newly formed woven bone from the original bone at 3-week healing period was observed in all samples. At the 12-week healing period, the new bone in the peripheral area was mainly lamellar and in the central region composed of both woven and lamellar bone. New bony tissue was found on the surface of all three types of granules and at the interior of the BBCP1 granules. Samples with 3% HA showed significantly less residual biomaterial in comparison to the other two groups. Furthermore, BBCP1 significantly promoted new bone area as compared to other three groups and more bone volume as compared to the control. Within its limitations, this study indicated the highest degradation rate in case of BBCP1 concomitant with the highest rate of bone formation. Hence, formation of new bone can be affected by the level of biomimetic HA coating of α-TCP.

Local Efficacy and Safety of Transarterial Chemoembolization for Hepatocellular Carcinoma: Epirubicin-Loaded DC Beads vs. Epirubicin-Lipiodol Emulsion with Gelatin Sponge (cTACE).

Purpose: To compare the efficacy and safety between epirubicin-loaded DC Beads (DCB-TACE) and conventional TACE (cTACE) used in transarterial chemoembolization (TACE) for hepatocellular carcinoma (HCC). Materials and Methods: This retrospective study enrolled 64 patients (mean age, 73.3 years; 44 men, 20 women) who underwent initial DCB-TACE between 2014 and 2015, and 66 patients (mean age, 71.3 years; 38 men, 28 women) who underwent initial cTACE between 2011 and 2013 as historical controls. Treatment effects on the target lesions at 3 months after TACE, the period until re-treatment of the target lesion, and adverse events after TACE were compared between the groups. Univariate and multivariate analyses were also performed to estimate the factors influencing the treatment effects. Results: Based on the Response Evaluation Criteria in Cancer of the Liver version 2015, treatment response of the target lesions equivalent to a complete response and termed as TE4, was 51.0% (53/104) in the DCB-TACE group and 74.4% (64/86) in the cTACE group (p<0.001). Multivariate analysis revealed that the TACE procedure, Child-Pugh score, serum aspartate aminotransferase (AST) level, alpha fetoprotein level, and tumor size were independent significant predictors of TE4. The frequencies of elevated serum AST and alanine transaminase levels after TACE were significantly lower in patients in the DCB-TACE group (p<0.001 each). No significant difference in biliary/liver damage was evident between the groups. Conclusion: The local efficacy of cTACE was higher than that of DCB-TACE. Adverse events were milder after DCB-TACE than after cTACE.

Transarterial chemoembolization for pulmonary or mediastinal metastases from hepatocellular carcinoma.

OBJECTIVE: To evaluate the feasibility, efficacy and safety of transcatheter arterial chemoembolization (TACE) with HepaSphere for patients with pulmonary or mediastinal metastases from hepatocellular carcinoma (HCC). METHODS: Between June 2009 and January 2018, 14 patients with pulmonary or mediastinal metastases from HCC were treated with TACE with a combination of 1-3 chemotherapeutic drugs followed by HepaSphere embolization. As first end point, local tumor response and adverse events were evaluated after the first session of TACE, with Response Evaluation Criteria In Solid Tumors v. 1.1 and Common Terminology Criteria for Adverse Events v. 4 criteria, respectively. Overall survival was evaluated as secondary end point. TACE was repeated on-demand. RESULTS: TACE with HepaSphere was well tolerated with acceptable safety profile and no 30 day mortality. 1 month objective response and disease control rate were calculated to be 7.1 and 100%, respectively. Mean tumor size reduction rate was 15.6±9.5% at the first month. Two Grade 3 cytopenia events were seen (14.3 %), however none of the Grade 2 or more post-embolization syndrome was observed. The median overall survival time was 15.0 months and the 1 year, 3 year and 5 year survival rate were, 57.1%, 28.6%, 19.1%, respectively. CONCLUSION: Early experience showed that the transarterial treatment with HepaSphere is safe and effective treatment for patients with pulmonary or mediastinal metastases from HCC. ADVANCES IN KNOWLEDGE: Currently, the effects of molecular targeted drugs on HCC metastases are limited and side-effects are relatively frequent. In the present study, transarterial treatment might be a promising treatment for HCC metastasis.

The efficacy of uterine artery embolization with gelatin sponge for retained products of conception with bleeding and future pregnancy outcomes.

BACKGROUND: Retained products of conception (RPOC) with hemorrhage need intervention when RPOC persist and remain symptomatic. The safety and efficacy of uterine artery embolization (UAE) for RPOC using gelatin sponge (GS) alone, and fertility after UAE for RPOC remain unknown. The purpose of this study is to retrospectively investigate the efficacy of UAE for RPOC with bleeding and future pregnancy outcomes. METHODS: Between 2007 and 2016, 14 patients (mean age, 33 years old) diagnosed as RPOC with bleeding received UAE using GS at our institution. Pregnancy outcomes were vaginal delivery (n = 7), miscarriage (n = 4), and termination (n = 3). Four patients received dilation and curettage/evacuation (D&C/E) for treatment of RPOC before bleeding occurred. The mean time interval from the end of pregnancy to bleeding was 28 days. Technical success, clinical success, complications, angiographic features and fertility after UAE were retrospectively assessed. RESULTS: Technical success was achieved in 13 patients (93%) and clinical success was achieved in all 14 patients. No major complications occurred. The angiographic features of RPOC were tortuous feeders with flow into a focal blush of contrast (n = 14). Additional findings were pseudoaneurysm (n = 6), early venous return (n = 4), and extravasation (n = 2). Pseudoaneurysm was observed significantly more often in patients who received D&C/E before UAE compared to those who received conservative treatment alone (P = 0.015). The mean follow-up period was 29 months. Six patients achieved six pregnancies an average of 29 months after UAE. CONCLUSION: UAE using GS may be an effective and safe treatment for RPOC with hemorrhage that can preserve fertility.

Electroporation-induced changes in tumor vasculature and microenvironment can promote the delivery and increase the efficacy of sorafenib nanoparticles.

Blood vessels, the extracellular space, and the cell membrane represent physiologic barriers to nanoparticle-based drug delivery for cancer therapy. We demonstrate that electroporation (EP) can assist in the delivery of dye stabilized sorafenib nanoparticles (SFB-IR783) by increasing the permeability of endothelial monolayers, improving diffusion through the extracellular space in tumorspheres, and by disrupting plasma membrane function in cancer cells. These changes occur in a dose-dependent fashion, increasing proportionally with electric field strength. Cell death from irreversible electroporation (IRE) was observed to contribute to the persistent transport of SFB-IR783 through these physiologic barriers. In a model of mice bearing bilateral xenograft HCT116 colorectal tumors, treatment with EP resulted in the immediate and increased uptake of SFB-IR783 when compared with the untreated contralateral tumor. The uptake of SFB-IR783 was independent of direct transfection of cells through EP and was mediated by changes in vascular permeability and extracellular diffusion. The combination of EP and SFB-IR783 was observed to result in 40% reduction in mean tumor diameter when compared with sham treatment (p < .05) at the time of sacrifice, which was not observed in cohorts treated with EP alone or SFB-IR783 alone. Treatment of tumor with EP can augment the uptake and increase the efficacy of nanoparticle therapy.

Deficiency of lysyl hydroxylase 2 in mice causes systemic endoplasmic reticulum stress leading to early embryonic lethality.

Lysyl hydroxylase 2 (LH2) is an endoplasmic reticulum (ER)-resident enzyme that catalyzes the hydroxylation of lysine residues in the telopeptides of fibrillar collagens. This is a critical modification to determine the fate of collagen cross-linking pathway that contributes to the stability of collagen fibrils. Studies have demonstrated that the aberrant LH2 function causes various diseases including osteogenesis imperfecta, fibrosis, and cancer metastasis. However, surprisingly, a LH2-deficient animal model has not been reported. In the current study, to better understand the function of LH2, we generated LH2 gene knockout mice by CRISPR/Cas9 technology. LH2 deficiency was confirmed by genotyping polymerase chain reaction (PCR), reverse transcriptase-PCR, and immunohistochemical analyses. Homozygous LH2 knockout (LH2-/-) embryos failed to develop normally and died at early embryonic stage E10.5 with abnormal common ventricle in a heart, i.e., an insufficient wall, a thin ventricular wall, and loosely packed cells. In the LH2-/- mice, the ER stress-responsive genes, ATF4 and CHOP were significantly up-regulated leading to increased levels of Bax and cleaved caspase-3. These data indicate that LH2 plays an essential role in cardiac development through an ER stress-mediated apoptosis pathway.

Toxicologic Pathology Forum: Current Status on the Use of Animal Models of Human Disease in the Pharmaceutical Industry in Japan in Nonclinical Safety Assessment-Opinion Paper.

In nonclinical safety studies for new drug development, healthy animals have been commonly used. However, in some cases, the use of animal models of human disease is considered to be more favorable in evaluating risks in patients. To elucidate the current status of the use of animal models for nonclinical safety assessment, an internal questionnaire from the Japan Pharmaceutical Manufacturers Association and surveys (questionnaire period: August 27 to September 30, 2015) of both common technical documents and review reports of approved drugs (approval period: May 1999 to May 2017) disclosed by the Pharmaceutical and Medical Devices Agency were conducted. Although there were some concerns and limitations raised, the survey results revealed that animal models have been used in nonclinical safety assessment on a case-by-case basis and that nonclinical safety studies using animal models were included in the data packages of several approved drugs in Japan. The survey results also revealed that nonclinical safety studies using animal models have become more frequent in the past few years. In almost all cases, useful information, such as signs of toxicity under disease conditions and mechanisms of toxic change, was obtained from the results of nonclinical studies using animal models. Note: This is an opinion article submitted to the Toxicologic Pathology Forum. It represents the views of the author(s). It does not constitute an official position of the Society of Toxicologic Pathology, British Society of Toxicological Pathology, or European Society of Toxicologic Pathology, and the views expressed might not reflect the best practices recommended by these Societies. This article should not be construed to represent the policies, positions, or opinions of their respective organizations, employers, or regulatory agencies.

Evidence for critical role of Tie2/Ang1 interaction in metastatic oral cancer.

Angiopoietin-1 (Ang1) is a binding partner of endothelial cell-specific tyrosine-protein kinase receptor (Tie2), which serves important roles in vascular development and angiogenesis. Tie2 is closely associated with the metastasis of oral squamous cell carcinomas (OSCCs) however, little is known about the correlation between Tie2 and Ang1. In the present study, the functional mechanisms of the Tie2/Ang1 interaction were investigated using Tie2 overexpressed (oeTie2) OSCC cells and recombinant Ang1 protein. oeTie2 cells had increased cell-cell and cell-extracellular matrix adhesions compared with the control cells. Additionally, the adhesive activities increased following treatment with exogenous Ang1, indicating that Ang1 directly enhances Tie2 functions. In the clinical OSCC data from 10 cases positive for regional lymph node metastasis, all cases were negative for Tie2 expression and eight cases (80%) were negative for Ang1 expression. These results suggest that Tie2 and Ang1 serve important roles in cancer metastasis and may be potential biomarkers and therapeutic targets for OSCC metastasis.

Long-Term Outcomes of Selective Renal Artery Embolization for Renal Arteriovenous Fistulae with Dilated Venous Sac.

PURPOSE: To retrospectively evaluate the role of selective renal artery embolization for renal arteriovenous fistulae (AVFs) with dilated venous sac. MATERIALS AND METHODS: Between 2002 and 2015, 14 patients (7 men and 7 women; mean age, 60 years) with a single renal AVF with dilated venous sac underwent selective renal artery embolization. Three patients presented with gross hematuria, 4 presented with occult blood in urine, and 1 presented with chronic heart failure. Five patients had a history of renal biopsy or partial nephrectomy. Embolic agents used included pushable fibered coils, detachable microcoils, hydrogel coils, N-butyl 2-cyanoactylate, and/or absolute ethanol. Technical success was defined as complete angiographic occlusion of the renal AVF without visualization of the venous sac. Clinical success was defined as the disappearance of the AVF on ultrasound and contrast-enhanced computed tomography, without any symptoms. RESULTS: Fifteen sessions of selective renal artery embolization were performed. Technical success was achieved in 13 sessions (86.7%). Clinical success was achieved in 13 patients (92.9%) after a mean follow-up of 48 months (range, 6-155 months). Two major complications occurred-renal vein thrombosis (n = 1) and renovascular hypertension (n = 1)-and were successfully managed with warfarin and an angiotensin-II receptor blocker, respectively. The former patient required re-embolization because of recanalization. No significant changes were observed in the mean serum creatinine level (.86 mg/dL vs .85 mg/dL; P = .67) and the mean estimated glomerular filtration rate (66.0 mL/min/1.73m2 vs 67.4 mL/min/1.73m2; P = .4) after 6 months. CONCLUSIONS: Selective renal artery embolization is a safe and effective treatment for renal AVFs with dilated venous sac.

Activin B Regulates Adhesion, Invasiveness, and Migratory Activities in Oral Cancer: a Potential Biomarker for Metastasis.

Activin B, a homodimer of inhibin beta b (INHBB), is a multifunctional cytokine belonging to the transforming growth factor-ß (TGF-ß) family. However, the molecular functions and clinical relevance of activin B have not been determined in oral cancer. We investigated the critical roles of activin B in oral squamous cell carcinoma (OSCC). We performed quantitative reverse transcriptase-polymerase chain reaction, Western blotting, and immunohistochemistry to study INHBB expression in OSCC-derived cell lines and OSCC clinical samples. The INHBB expression levels were significantly (P < 0.05) overexpressed in OSCCs compared to normal counterparts in vitro and in vivo. Activin B-positivity in OSCC cases was significantly (P < 0.05) correlated with regional lymph node metastasis. The INHBB knockdown (shINHBB) cells promoted cellular adhesion and suppression of cellular invasiveness and migration. After treatment of shINHBB cells with activin B, those activities were restored similar to the shMock cells. In the processes of invasiveness and metastasis, the cells cause epithelial-mesenchymal transition (EMT). TGF-ß and its family members are promoters of the EMT process. To investigate whether activin B is related to EMT, we examined the expressions of EMT-related genes and found that INHBB was related closely to EMT. Our results suggested for the first time that activin B indicates tumoral metastasis in OSCCs and might be a useful biomarker for OSCC metastasis.

Evidence for Critical Role of Lymphocyte Cytosolic Protein 1 in Oral Cancer.

Lymphocyte cytosolic protein 1 (LCP1), a member of actin-binding protein of the plastin family, has been identified in several malignant tumors of non-hematopoietic sites, such as the colon, prostate, and breast. However, little is known about the roles of LCP1 in oral squamous cell carcinomas (OSCCs). This present study sought to clarify the clinical relevance of LCP1 in OSCCs and investigate possible clinical applications for treating OSCCs by regulating LCP1 expression. We found up-regulation of LCP1in OSCCs compared with normal counterparts using real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR), immunoblotting, and immunohistochemistry (P < 0.05). We used shRNA models for LCP1 (shLCP1) and enoxacin (ENX), a fluoroquinolone antibiotic drug, as a regulator of LCP1 expression. In addition to the LCP1 knockdown experiments in which shLCP1 cells showed several depressed functions, including cellular proliferation, invasiveness, and migratory activities, ENX-treated cells also had attenuated functions. Consistent with our hypothesis from our in vitro data, LCP1-positive OSCC samples were correlated closely with the primary tumoral size and regional lymph node metastasis. These results suggested that LCP1 is a useful biomarker for determining progression of OSCCs and that ENX might be a new therapeutic agent for treating OSCCs by controlling LCP1 expression.

Tie2 Regulates Tumor Metastasis of Oral Squamous Cell Carcinomas.

The endothelial-specific receptor, tyrosine kinase with immunoglobulin-like loops and epidermal growth factor homology domains-2 (Tie2) is a member of the tyrosine kinase family and is ubiquitous in normal tissues; however, little is known about the mechanisms and roles of Tie2 in oral squamous cell carcinomas (OSCCs). In the current study, we investigated the expression status of Tie2 in OSCCs by quantitative reverse transcriptase-polymerase chain reaction, immunoblotting, and immunohistochemistry and the functional mechanisms of Tie2 using its overexpressed OSCC (oeTie2) cells and Tie2 blocking by its antibody. We found that Tie2 expression was down-regulated significantly (p < 0.05) in OSCCs compared with normal counterparts in vitro and in vivo. Interestingly, oeTie2 cells showed higher cellular adhesion (p < 0.05) and lower cellular invasion (p < 0.05) compared with control cells; whereas there was similar cellular proliferation in both transfectants. Furthermore, cellular adhesion was inhibited and invasion was activated by Tie2 function-blocking antibody (p < 0.05), indicating that Tie2 directly regulates cellular adhesion and invasion. As expected, among the clinical variables analyzed, Tie2-positivity in patients with OSCC was correlated closely with negative lymph node metastasis. These results suggested for the first time that Tie2 plays an important role in tumor metastasis and may be a potential biomarker for OSCC metastasis.

ARNT2 Regulates Tumoral Growth in Oral Squamous Cell Carcinoma.

Aryl hydrocarbon receptor nuclear translocator (ARNT) 2 is a transcriptional factor related to adaptive responses against cellular stress from a xenobiotic substance. Recent evidence indicates ARNT is involved in carcinogenesis and cancer progression; however, little is known about the relevance of ARNT2 in the behavior of oral squamous cell carcinoma (OSCC). In the current study, we evaluated the ARNT2 mRNA and protein expression levels in OSCC in vitro and in vivo and the clinical relationship between ARNT2 expression levels in primary OSCCs and their clinicopathologic status by quantitative reverse transcriptase-polymerase chain reaction, immunoblotting, and immunohistochemistry. Using ARNT2 overexpression models, we performed functional analyses to investigate the critical roles of ARNT2 in OSCC. ARNT2 mRNA and protein were down-regulated significantly (P < 0.05 for both comparisons) in nine OSCC-derived cells and primary OSCC (n=100 patients) compared with normal counterparts. In addition to the data from exogenous experiments that ARNT2-overexpressed cells showed decreased cellular proliferation, ARNT2-positive OSCC cases were correlated significantly (P < 0.05) with tumoral size. Since von Hippel-Lindau tumor suppressor, E3 ubiquitin protein ligase, a negative regulator of hypoxia-inducible factor (HIF1)-α, is a downstream molecule of ARNT2, we speculated that HIF1-α and its downstream molecules would have key functions in cellular growth. Consistent with our hypothesis, overexpressed ARNT2 cells showed down-regulation of HIF1-α, which causes hypofunctioning of glucose transporter 1, leading to decreased cellular growth. Our results proposed for the first time that the ARNT2 level is an indicator of cellular proliferation in OSCCs. Therefore, ARNT2 may be a potential therapeutic target against progression of OSCCs.