Reliability of online dental final exams in the pre and post COVID-19 era: A comparative study

Amidst the fourth COVID-19 wave in Viet Nam, national lockdowns necessitated the closure of numerous dental schools. To assess DDS (Doctor of Dental Surgery) graduation exams, this study analyzed their 2021 implementation in comparison to onsite exams conducted in 2020 and 2022 at the Faculty of Odonto-Stomatology, University of Medicine and Pharmacy at Ho Chi Minh City, Viet Nam (FOS-UMPH). The final online examination comprises two main sessions: a synchronous online examination using FOS-UMPH e-Learning for theories (consisting of 200 MCQs and 3 written tests with 3 clinical situations needed be solved) and a synchronous online examination using Microsoft Teams for practicum (comprising of 12 online OSCE stations). The final grades were evaluated using the same metrics in face-to-face final examinations in 2022 and 2020. A total of 114, 112 and 95 students were recruited for the first-time exams in 2020, 2021 and 2022, respectively. In order to analyze the reliability, histogram and k-mean clustering were employed. The histograms from 2020, 2021 and 2022 showed a striking similarity. However, fewer students failed in 2021 and 2022 (13% and 12.6%, respectively) compared to 2020 (28%), with clinical problem-solving part grades (belonging to theory session) being notably higher in 2021 and 2022. Intriguingly, the MCQ Score results showed the identical patterns. The courses of orthodontics, dental public health, and pediatrics subjects (in the group of prevention and development dentistry) stood out for their exceptional accuracy across both sessions. After examining data gathered over three years, we identified three distinct clusters: the first comprised of scattered average and low scores, the second characterized by high scores but unstable and scattered and the third cluster boasting consistently high and centered scores. According to our study, online and onsite traditional graduation exam results are relatively equivalent, but additional measures are necessary to standardize the final examination and adapt to the new normal trend in dental education.

Searching for New Molecular Targets for Oral Squamous Cell Carcinoma with a View to Clinical Implementation of Precision Medicine

Head and neck cancer, including oral squamous cell carcinoma (OSCC), is the eighth most common malignancy globally and is characterized by local invasiveness and high nodal metastatic potential. The OSCC incidence is also increasing, and the number of deaths is also rising steadily in Japan. The development of molecular markers to eradicate OSCC is an urgent issue for humankind. The increase in OSCC despite the declining smoking rate may be due to several viral infections through various sexual activities and the involvement of previously unfocused carcinogens, and genetic alterations in individual patients are considered to be more complicated. Given this situation, it is difficult to combat OSCC with conventional radiotherapy and chemotherapy using cell-killing anticancer drugs alone, and the development of precision medicine, which aims to provide tailor-made medicine based on the genetic background of each patient, is gaining attention. In this review article, the current status of the comprehensive search for driver genes and biomarkers in OSCC will be briefly described, and some of the candidates for novel markers of OSCC that were found will be outlined.

SERPINE2 is an oral cancer-promoting factor that induces angiogenesis and lymphangiogenesis

BACKGROUND

LEM domain containing 1 (LEMD1) is a novel factor involved in the development of oral squamous cell carcinoma (OSCC). We previously performed a microarray analysis and found that serpin peptidase inhibitor, clade E, member 2 (SERPINE2) is an LEMD1-related signal. SERPINE2 is an extracellular serine proteinase inhibitor with secretory capacity. Although SERPINE2 displays tumor-promoting properties in many cancers, some reports indicate that SRPINE2 also has a tumor-suppressing function. Therefore, there are many unclear points about its role in cancer. In this study, we investigated SERPINE2 expression in OSCC.

METHODS

The gene expression and secretion levels of SERPINE2 were examined in 42 frozen specimens of OSCC, and SERPINE2 immunostaining was investigated in 167 cases of OSCC. Furthermore, the effect of SERPINE2 on angiogenesis and lymphangiogenesis was analyzed using OSCC cells and endothelial cells.

RESULTS

In the frozen specimens, the gene expression (P < 0.0001) and secretion levels (P < 0.0001) of SERPINE2 were higher in OSCC than in the normal oral mucosa. According to the immunohistochemical analysis, SERPINE2 expression was correlated with the depth of invasion (P = 0.0163), nodal metastasis (P = 0.0085), microvessel density (P < 0.0001), and lymphovessel density (P < 0.0001). Additionally, univariate and multivariate analyses indicated that the SERPINE2 expression level was an independent poor prognostic factor for OSCC. In vitro studies using OSCC cells revealed that SERPINE2 promotes angiogenesis and lymphangiogenesis.

CONCLUSION

These results suggest that SRPX2 might be a useful tumor marker for OSCC.

Peroxidan Plays a Tumor-Promoting Role in Oral Squamous Cell Carcinoma

Despite dramatic progress in cancer diagnosis and treatment, the five-year survival rate of oral squamous cell carcinoma (OSCC) is still only about 50%. Thus, the need for elucidating the molecular mechanisms underlying OSCC is urgent. We previously identified the peroxidasin gene (PXDN) as one of several novel genes associated with OSCC. Although the PXDN protein is known to act as a tumor-promoting factor associated with the Warburg effect, its function and role in OSCC are poorly understood. In this study, we investigated the expression, function, and relationship with the Warburg effect of PXDN in OSCC. In immunohistochemical analysis of OSCC specimens, we observed that elevated PXDN expression correlated with lymph node metastasis and a diffuse invasion pattern. High PXDN expression was confirmed as an independent predictor of poor prognosis by multivariate analysis. The PXDN expression level correlated positively with that of pyruvate kinase (PKM2) and heme oxygenase-1 (HMOX1) and with lactate and ATP production. No relationship between PXDN expression and mitochondrial activation was observed, and PXDN expression correlated inversely with reactive oxygen species (ROS) production. These results suggest that PXDN might be a tumor progression factor causing a Warburg-like effect in OSCC.

Sushi Repeat Containing Protein X-linked 2 Is a Downstream Signal of LEM Domain Containing 1 and Acts as a Tumor-Promoting Factor in Oral Squamous Cell Carcinoma

Because oral squamous cell carcinomas (OSCCs) have a high potential for locoregional invasion and nodal metastasis, early detection and treatment are essential. A LAP2, emerin, MAN1 (LEM) domain containing 1 (LEMD1) is associated with local progression, clinical stage, nodal metastasis, poor prognosis, angiogenesis, and lymphangiogenesis in OSCC. Although LEMD is a cancer-testis antigen, the cancer-related signals related to LEMD1 remain unknown. In this study, we used a microarray analysis of OSCC cells to identify sushi repeat containing protein X-linked 2 (SRPX2) as a LEMD1-related downstream signal. LEMD1 expression was correlated with lymph node metastasis of OSCC according to the immunohistochemistry analysis. Furthermore, patients expressing SRPX2 had a significantly worse prognosis than those without SRPX2 expression. The concentration of SRPX2 in OSCC was positively correlated with the concentrations of LEMD1, urokinase plasminogen activator receptor (uPAR), and hepatocyte growth factor (HGF). In OSCC cells, SRPX2 secretion levels were elevated by interactions with uPAR and HGF. We also found that SRPX2 promotes endothelial cell proliferation and adhesion between endothelial cells and OSCC cells. These results suggest that SRPX2 might be a useful tumor marker for OSCC.

Mast cell chymase promotes angiogenesis and lymphangiogenesis mediated by activation of melanoma inhibitory activity gene family members in oral squamous cell carcinoma

Mast cells (MCs) are present in the tumor stroma, and MCs that express the mast cell‑specific proteases tryptase and chymase (MCTC) exhibit several tumor‑related functions. It was previously reported that melanoma inhibitory activity (MIA) gene family members, including MIA, MIA2, and transport and Golgi organization protein 1 (TANGO), possess oncogenic functions in oral squamous cell carcinoma (OSCC). However, the relationships between MCTC, and clinicopathological characteristics and activation of the MIA gene family in OSCC remain unknown. In the present study, the functional roles of MCTC in patients with OSCC were investigated using immunohistochemistry and reverse transcription‑quantitative PCR. In addition, the effects of extracellular chymase on oral cancer cells were examined. In patients with OSCC, MCTC density was significantly affected by tumor progression and nodal metastasis, and was correlated with vessel density. MCTC density was also correlated with MIA and MIA2 expression. In OSCC cells, extracellular chymase promoted the secretion of vascular endothelial growth factor family proteins, and the transmigration and adhesion of HSC3 cells to endothelial cells; knockdown of MIA, MIA2 and TANGO attenuated these effects. The present findings indicated that MCTC act as tumor‑progressive factors in OSCC via the activation and secretion of MIA and MIA2, and the induction of angiogenesis and lymphangiogenesis.

The Multifarious Functions of Pyruvate Kinase M2 in Oral Cancer Cells

Head and neck cancers, including oral squamous cell carcinoma (OSCC), are the sixth most common malignancies worldwide. OSCC frequently leads to oral dysfunction, which worsens a patient’s quality of life. Moreover, its prognosis remains poor. Unlike normal cells, tumor cells preferentially metabolize glucose by aerobic glycolysis. Pyruvate kinase (PK) catalyzes the final step in glycolysis, and the transition from PKM1 to PKM2 is observed in many cancer cells. However, little is known about PKM expression and function in OSCC. In this study, we investigated the expression of PKM in OSCC specimens and performed a functional analysis of human OSCC cells. We found that the PKM2/PKM1 ratio was higher in OSCC cells than in adjacent normal mucosal cells and in samples obtained from dysplasia patients. Furthermore, PKM2 expression was strongly correlated with OSCC tumor progression on immunohistochemistry. PKM2 expression was higher during cell growth, invasion, and apoptosis in HSC3 cells, which show a high energy flow and whose metabolism depends on aerobic glycolysis and oxidative phosphorylation. PKM2 expression was also associated with the production of reactive oxygen species (ROS) and integration of glutamine into lactate. Our results suggested that PKM2 has a variety of tumor progressive functions in OSCC cells.

Downregulation of DHRS9 is associated with poor prognosis in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) has a high potential for local invasion and nodal metastasis. Therefore, early detection and elucidation of the detailed molecular mechanisms underlying OSCC are essential. Dehydrogenase/reductase member 9 (DHRS9) is downregulated in recurrent OSCC. Although DHRS9 is reported to act as a tumour suppressor in several malignancies, its expression in OSCC cells is unknown. In this study, we examined DHRS9 expression immunohistochemically in specimens from a sample of 98 OSCC patients. Reduced DHRS9 expression was observed in 68 of 98 patients (69.4%) with OSCC. A significant association was found between low DHRS9 expression and local progression (T factor) (p = 0.0135). Furthermore, patients with low DHRS9 expression had a significantly poorer prognosis than those with high DHRS9 expression (p = 0.0443). In multivariate analysis using the Cox proportional hazards model, decreased DHRS9 expression strongly correlated with worse prognosis. The study findings suggest that DHRS9 might be a useful diagnostic and prognostic marker for OSCC.

Expression of cytosolic malic enzyme (ME1) is associated with disease progression in human oral squamous cell carcinoma

Malic enzyme 1 (ME1) is a multifunctional protein involved in glycolysis, the citric acid cycle, NADPH production, glutamine metabolism, and lipogenesis. It is overexpressed in various cancers. We examined the expression of ME1 in 119 oral squamous cell carcinomas (OSCCs) using immunohistochemistry. Malic enzyme 1 expression was moderate to strong in 57 (48%) OSCCs and correlated with pT, pN, clinical stage, and histological grade. In 37 cases with prognostic evaluation, moderate to strong ME1 expression indicated a worse prognosis than did weak ME1 expression. Malic enzyme 1 knockdown or inactivation by lanthanide inhibited cell proliferation and motility and suppressed the epithelial-mesenchymal transition in HSC3 human OSCC cells. Knockdown of ME1 also shifted energy metabolism from aerobic glycolysis and lactate fermentation to mitochondrial oxidative phosphorylation, and the redox status from reductive to oxidative. In a mouse tumor model, lanthanide suppressed tumor growth and increased survival time. These findings reveal that ME1 is a valid target for molecular therapy in OSCC.

The importance of melanoma inhibitory activity gene family in the tumor progression of oral cancer

Oral squamous cell carcinoma has a high potential for locoregional invasion and nodal metastasis. Consequently, early detection of such malignancies is of immense importance. The melanoma inhibitory activity (MIA) gene family comprises MIA, MIA2, transport and Golgi organization protein 1 (TANGO), and otoraplin (OTOR). These members of the MIA gene family have a highly conserved Src homology 3 (SH3)-like structure. Although the molecules of this family share 34-45% amino acid homology and 47-59% cDNA sequence homology, those members, excluding OTOR, play different tumor-associated functions. MIA has a pivotal role in the progression and metastasis of melanoma; MIA2 and TANGO have been suggested to possess tumor-suppressive functions; and OTOR is uniquely expressed in cochlea of the inner ear. Therefore, the definite functions of the MIA gene family in cancer cells remain unclear. Since the members of the MIA gene family are secreted proteins, these molecules might be useful tumor markers that can be detected in the body fluids, including serum and saliva. In this review, we described the molecular biological functions of the MIA gene family in oral cancer.

NIPA-like domain containing 1 is a novel tumor-promoting factor in oral squamous cell carcinoma

PURPOSE

In our previous global gene expression analysis, we identified NIPA-like domain containing 1 (NIPAL1), which encodes a magnesium transporter, as one of the most overexpressed genes in recurrent oral squamous cell carcinoma (OSCC). Although has been NIPAL1 linked with gout pathogenesis, little is known about its expression and function in human malignancies.

METHODS

In this study, we examined NIPAL1 expression in 192 cases of OSCC by immunohistochemistry and performed a functional analysis of human OSCC cells.

RESULTS

NIPAL1 immunostaining was observed in 39 of 192 OSCC patients (20.3%). NIPAL1 expression correlated significantly with cancer cell intravsation (P = 0.0062), as well as with poorer disease-free survival in a Kaplan-Meier analysis (P < 0.0001). Moreover, a multivariate Cox proportional hazards model analysis revealed that NIPAL1 expression was an independent predictor of disease-free survival in OSCC (P < 0.0001). In a functional analysis, NIPAL1 regulated the growth and adhesion of OSCC tumor cells and endothelial cells.

CONCLUSIONS

Our findings suggest that NIPAL1 might be a novel factor promoting OSCC tumorigenesis, as well as a useful molecular marker of OSCC.

A comprehensive expression analysis of the MIA gene family in malignancies: MIA gene family members are novel, useful markers of esophageal, lung, and cervical squamous cell carcinoma

Melanoma inhibitory activity (MIA) gene family members include MIA, MIA2, and Transport and Golgi organization protein 1 (TANGO). Although MIA gene family members have several tumor-related functions, their detailed roles in malignancies remain poorly elucidated. In this study, 477 tumor specimens were subjected to immunohistochemical screening to evaluate MIA gene family expression. For a validation analysis, we also examined the association between MIA gene family expression and clinicopathological factors in 66 cases of esophageal cancer, 145 cases of lung cancer, and 126 cases of cervical cancer. The frequency of MIA gene family expression was higher among squamous cell carcinomas than among other tumor types subjected to screening. In the validation analysis, MIA gene family staining was observed frequently in esophageal and lung cancers associated with nodal and/or distant metastasis. In cervical cancers, MIA and TANGO immunostaining also correlated with tumor progression and metastasis. Furthermore, MIA2 expression levels in invasive cervical cancer were upregulated relative to those in cervical intraepithelial neoplasia 3. A disease-free survival analysis revealed that MIA-, MIA2, or TANGO-positive patients had a significantly shorter disease-free survival than did those patients who were negative. Our results suggest that MIA, MIA2, and TANGO may be useful diagnostic and therapeutic molecular targets in human malignancies.

Storkhead box 2 and melanoma inhibitory activity promote oral squamous cell carcinoma progression

Background

Storkhead box protein 2 (STOX2) is a transcriptional factor associated with pre-eclampsia with fetal growth restriction. We recently reported that melanoma inhibitory activity (MIA) promotes oral squamous cell carcinoma (OSCC) progression. However, the relationship between STOX2 and MIA remains unknown in malignancies.

Methods

We used immunohistochemistry and PCR to investigate MIA and STOX2 expression in OSCC. We also performed functional analysis in human OSCC cells.

Results

MIA and STOX2 mRNA levels were higher in OSCCs than in normal oral epithelial cells, and upregulation of STOX2 was significantly correlated with overexpression of MIA. Immunostaining for STOX2 was associated with nodal metastasis (P = 0.0002) and MIA expression (P < 0.0001). Furthermore, MIA expression (P = 0.0035) and STOX2 expression (P = 0.0061) were associated with poor outcome in OSCCs. In vitro analysis using OSCC cells revealed that MIA increased expression of STOX2 by paracrine manner. Moreover, STOX2 accelerated OSCC cell growth, invasion, suppressed apoptosis, and enhanced resistance to paclitaxel, cisplatin, and 5-FU.

Conclusions

Our results suggest that MIA-STOX2 signaling may be a useful diagnostic and therapeutic target in OSCCs.

Zinc finger AN1-type containing 4 is a novel marker for predicting metastasis and poor prognosis in oral squamous cell carcinoma

AIMS

Head and neck cancer, including oral squamous cell carcinoma (OSCC), is the sixth most common cancer worldwide and has a high potential for locoregional invasion and nodal metastasis. Therefore, discovery of a useful molecular biomarker capable of predicting tumour progression and metastasis of OSCC is crucial. We have previously reported zinc finger AN1-type containing 4 (ZFAND4) as one of the most upregulated genes in recurrent OSCC using a cDNA microarray analysis. Although ZFAND4 has been shown to promote cell proliferation of gastric cancer, its expression and clinicopathological roles in OSCC remain unclear.

METHODS

In this study, we examined ZFAND4 expression by immunohistochemistry in 214 cases of OSCC.

RESULTS

High cytoplasmic expression of ZFAND4 was observed in 45 out of 214 (21%) patients with OSCC. Expression levels of ZFAND4 were strongly associated with metastasis to the lymph nodes (p=0.0429) and distant organs (p=0.0068). Cases with high expression of ZFAND4 had a significantly unfavourable prognosis compared with patients with low expression of ZFAND4 (p<0.0001). Furthermore, ZFAND4 overexpression was an independent poor prognostic factor for OSCC as determined by multivariate analysis using the Cox proportional hazards model (p<0.0001).

CONCLUSIONS

These results suggest that ZFAND4 is a useful marker for predicting metastasis and poor prognosis in patients with OSCC.

microRNA-203 suppresses invasion and epithelial-mesenchymal transition induction via targeting NUAK1 in head and neck cancer

Head and neck squamous cell carcinoma (HNSCC) has a high capacity for invasion. To identify microRNAs (miRNAs) that regulate HNSCC invasion, we compared miRNA expression profiles between a parent HNSCC cell line and a highly invasive clone. The miR-200 family and miR-203 were downregulated in the clone. Here we focused on the role of miR-203 in invasion and epithelial-mesenchymal transition (EMT) induction in HNSCC. miR-203 was downregulated during EMT induction. Moreover, ectopic overexpression of miR-203 suppressed the invasion and induced mesenchymal-epithelial transition (MET) in HNSCC cells. Interestingly, we identified NUAK family SNF1-like kinase 1 (NUAK1) as a novel target gene of miR-203 by cyclopedic analysis using anti-Ago2 antibody. Increased expression of NUAK1 was observed during EMT induction, and ectopic expression of miR-203 delayed EMT induction by suppressing NUAK1 expression. Moreover, NUAK1 overexpression promoted the invasion of HNSCC cells. Importantly, NUAK1 expression was well correlated with poor differentiation, invasiveness, and lymph node metastasis in HNSCC cases. Overall, miR-203 has a tumor-suppressing role in invasion and EMT induction by targeting NUAK1 in HNSCC, suggesting miR-203 as a potential new diagnostic and therapeutic target for the treatment of HNSCC.

Pancreatic adenocarcinoma up-regulated factor has oncogenic functions in oral squamous cell carcinoma

AIMS

Pancreatic adenocarcinoma up-regulated factor (PAUF) is a novel secretory protein which promotes tumour progression, metastasis and poor prognosis in pancreatic, cervical and colorectal carcinoma. It is also associated with gemcitabine resistance in pancreatic cancer cells. However, the expression and function of PAUF in oral squamous cell carcinoma (OSCC) remain unknown.

METHODS AND RESULTS

We performed an immunohistochemical analysis of PAUF in 222 clinicopathologically characterized cases of OSCC. We also investigated the growth, invasion, apoptosis induction and cisplatin resistance of OSCC cells under PAUF knockdown treatment. PAUF was localized in normal salivary glands. In OSCC, immunostaining for PAUF was found in 52 of 222 patients (23.4%), and correlated with nodal metastasis (P < 0.0001) and poor prognosis (P < 0.0001). Multivariate analysis using the Cox proportional hazards model identified that PAUF expression was an independent predictor of disease-free survival in OSCC (P < 0.0001). The down-regulation of PAUF in OSCC cells suppressed cell growth and invasion and induced apoptosis and cisplatin sensitivity.

CONCLUSIONS

Our results suggest that PAUF has tumour-promoting functions in OSCC. It may thus be a useful diagnostic and therapeutic marker for OSCC.

Abstract 1699: Protumoral role of trans fatty acid in colorectal cancer

Trans fatty acids (TFAs) is a recent focus of health problems. TFA is a definitive risk factor for cardiovascular diseases and the death. TFA is also possible risk factor for Alzheimer's disease, obesity, diabetes, fatty liver, and ovulation infertility. Relation of TFA with carcinogenic risk is controversy; however, TFA is reported to increase the risk of breast cancer and prostate cancer. Elaidic acid (EA), a trans form of oleic acid, enhances cancer cell growth, invasion, and anti-apoptotic survival. By animal models, EA promotes tumor growth and metastasis to the lung, liver, and peritoneum. EA induces stemness in cancer cells through transactivation of EFGR via SRC from GPR40/120 as receptors in EA-integrated cholesterol raft. Activated EGFR relays the signals to activate canonical and non-canonical wnt pathway and to inactivate notch1 pathways. EA also increases miR-494, which inhibits cell differentiation through decrease of target genes. Continuous EA feeding with dosage alteration increased cancer cell stemness. EA diminishes the efficiency of 5-fluorouracil by increase of residual cancer stem cells. These findings suggest that TFA is a relevant cancer promoting factor. Decision of removal of TFA from foods by FDA might provide an impact to cancer clinics.

Citation Format: Hitoshi Ohmori, Toshio Kuwai, Yasuhiko Kitadai, Kiyomu Fujii, Rina Fujiwara, Yukiko Nishiguchi, Tomonori Sasahira, Hiroki Kuniyasu. Protumoral role of trans fatty acid in colorectal cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1699.

Expression of MAS1 in breast cancer

MAS1 is a receptor for angiotensin 1-7 (A1-7), which is derived from angiotensin II (A-II) by the action of angiotensin converting enzyme (ACE) 2. MAS1 induces anti-A-II phenotypes, such as vessel dilation and depression of blood pressure. Using immunohistochemistry, we examined the role of MAS1 in 132 cases of invasive ductal carcinoma (IDC) of the breast. While benign mammary tissues expressed MAS1 at high levels, MAS1 expression was attenuated in all IDC, especially in scirrhous IDC. The decrease in MAS1 expression was associated with tumor growth, lymph node metastasis, and grade. MAS1 expression was inversely associated with the proliferation index and epidermal growth factor receptor and human epidermal growth factor receptor-2 expression. Of the 132 cases, 12 (9.1%) were triple-negative breast cancer (TNBC) cases. All TNBC cases (the 12 cases and the additional 36 cases using a tissue array) expressed MAS1. Using the TNBC cell lines 4T1 and MDA-MB-468, which expresses MAS1, we found that cell growth, anti-apoptotic survival and invasion were suppressed by MAS1 activation with A1-7 treatment and enhanced by MAS1 knockdown. In contrast, synergic effect was found between tamoxifen and A1-7 in a luminal A breast cancer cell line, MCF-7. Combination treatment with cisplatin, an ACE2 activator, and an A-II type 1 receptor blocker showed synergic effects on tumor growth inhibition of 4T1 tumors in a syngeneic mouse model. These findings suggest that MAS1 might act as an inhibitory regulator of breast cancer and may be a possible molecular target for this malignancy.

HuD promotes progression of oral squamous cell carcinoma

Head and neck cancer, including oral squamous cell carcinoma (OSCC), ranks as the sixth most common malignancy worldwide. Overall 5-year survival rates of OSCC have not significantly improved during the past 3 decades and the 5-year survival rate is less than 50%. Several invasion grading systems have been employed in OSCC, however, their utility is still controversial. HuD belongs to the Hu protein family and acts as an RNA-binding protein involved in mRNA stability and translational regulation. Although HuD has a pivotal role for neuronal differentiation, the functional role of HuD in OSCCs is still unclear. In this study, we examined HuD expression in 82 OSCC cases. Expression of HuD was observed in 36.6% of OSCCs and significantly associated with histological differentiation, nodal metastasis and mode of invasion. HuD expression in high-metastatic HSC3 cells was higher than in low-metastatic HSC4 cells, and inhibition of invasion ability and activation of caspase-3 were shown by HuD siRNA-treated HSC3 cells. Furthermore, we clarified that HuD regulates expression of vascular endothelial growth factor (VEGF)-A, VEGF-D, matrix metallopeptidase (MMP)-2 and MMP-9. These results suggest that HuD is a useful diagnostic and therapeutic target in OSCCs.

[18F]fluoro-2-deoxyglucose-positron emission tomography for the assessment of histopathological response after preoperative chemoradiotherapy in advanced oral squamous cell carcinoma

BACKGROUND

[(18)F]fluoro-2-deoxyglucose-positron emission tomography (FDG-PET) is widely used to evaluate tumor metabolic activity. The aim of this study was to evaluate the usefulness of FDG-PET in assessing the histopathological response to preoperative concurrent chemoradiotherapy (CRT) in patients with oral squamous cell carcinoma (OSCC).

METHODS

Forty-five patients with resectable advanced OSCC who had received preoperative CRT followed by tumor ablative surgery between January 2004 and December 2011 were included in the study. All patients underwent FDG-PET before and after preoperative CRT. The maximum standardized uptake value (SUVmax) before (pre-SUV) and after preoperative CRT (post-SUV) and the SUVmax reduction rate (ΔSUV %) were used to evaluate the response to preoperative CRT. Correlations among SUVmax, histopathological response, and expression of cancer antigen Ki-67 and hypoxia-inducible factor-1α (HIF-1α) were analyzed.

RESULTS

Preoperative CRT significantly reduced intratumoral FDG uptake (P < 0.001). The pre-SUV and post-SUV were significantly lower in patients with a pathological complete response (pCR) than in those with a non-pCR (pre-SUV P = 0.037; post-SUV P = 0.001). ΔSUV % was higher in patients with pCR than in those with non-pCR (P = 0.029). The pre-SUV was significantly correlated with Ki-67 and HIF-1α expression in pretreatment biopsy specimens (Ki-67 P = 0.046, R = 0.292; HIF-1α P = 0.007, R = 0.385). The expression of both Ki-67 and HIF-1α was significantly lower in patients with pCR than in those with non-pCR (Ki-67 P < 0.001; HIF-1α P < 0.001).

CONCLUSIONS

Low pre-SUV and post-SUV and high ΔSUV % may predict a good histopathological response to preoperative CRT. Ki-67 and HIF-1α expression in pretreatment biopsy specimens were predictors of histopathological response to preoperative CRT.

Prox1 and FOXC2 act as regulators of lymphangiogenesis and angiogenesis in oral squamous cell carcinoma

Prospero homeobox 1 (Prox1) and forkhead box (FOX) C2 regulate angiogenesis and/or lymphangiogenesis. However, the detailed role and function of Prox1 and FOXC2 in cancer remains controversial. In the present study, we examined the expression of Prox1 and FOXC2 proteins in specimens from 163 cases with oral squamous cell carcinoma (OSCC). Furthermore, the role of Prox1 and FOXC2 in cancer cell growth and invasion was evaluated in cultured OSCC cells. Prox1 expression was significantly associated with local progression of the tumor (P = 0.0023), clinical stage (P<0.0001), lymphovessel density (LVD) (P<0.0001), nodal metastasis (P<0.0001), and worse prognosis (P<0.0001). Immunoreactivity of FOXC2 was strongly correlated with microvessel density (MVD) (P<0.0001) and poor prognosis (P = 0.0076). In vitro analysis demonstrated that Prox1 regulates cell growth, proliferation, invasion, and lymphangiogenesis by activating vascular endothelial growth factor (VEGF)-C expression. Furthermore, FOXC2 enhanced the expression level of Prox1 and promoted angiogenesis by enhancement of VEGF-A expression. Our results suggested that Prox1 and FOXC2 play key roles in OSCC progression and that further studies focusing on these proteins may yield useful insights for diagnosis and therapy of OSCC.

Cancer usurps skeletal muscle as an energy repository

Cancer cells produce energy through aerobic glycolysis, but contributions of host tissues to cancer energy metabolism are unclear. In this study, we aimed to elucidate the cancer-host energy production relationship, in particular, between cancer energy production and host muscle. During the development and progression of colorectal cancer, expression of the secreted autophagy-inducing stress protein HMGB1 increased in the muscle of tumor-bearing animals. This effect was associated with decreased expression of pyruvate kinase PKM1 and pyruvate kinase activity in muscle via the HMGB1 receptor for advanced glycation endproducts (RAGE). However, muscle mitochondrial energy production was maintained. In contrast, HMGB1 addition to colorectal cancer cells increased lactate fermentation. In the muscle, HMGB1 addition induced autophagy by decreasing levels of active mTOR and increasing autophagy-associated proteins, plasma glutamate, and (13)C-glutamine incorporation into acetyl-CoA. In a mouse model of colon carcinogenesis, a temporal increase in HMGB1 occurred in serum and colonic mucosa with an increase in autophagy associated with altered plasma free amino acid levels, increased glutamine, and decreased PKM1 levels. These differences were abolished by administration of an HMGB1 neutralizing antibody. Similar results were obtained in a mouse xenograft model of human colorectal cancer. Taken together, our findings suggest that HMGB1 released during tumorigenesis recruits muscle to supply glutamine to cancer cells as an energy source.

Protumoral roles of melanoma inhibitory activity 2 in oral squamous cell carcinoma

BACKGROUND

The role of melanoma inhibitory activity 2 (MIA2) was examined in human oral squamous cell carcinoma (OSCC).

METHODS

MIA2 role was examined by immunohistochemistry of human OSCCs and knockdown studies using human 3 OSCC cell lines with MIA2 expression.

RESULTS

MIA2 expression was observed in 62 (66.7%) of 93 OSCCs and was associated with tumour expansion and nodal metastasis. Melanoma inhibitory activity 2 expression was inversely correlated with intratumoral infiltration of lymphocytes. Invasion and anti-apoptotic survival were reduced by MIA2 knockdown in HSC3 cells. MOLT-3 lymphocytes infiltrating the HSC3 cell layer was enhanced by MIA2 knockdown or MIA2 depletion with the antibody. In HSC3 cells, MIA2 knockdown decreased the expressions of vascular endothelial growth factor (VEGF), VEGF-C, and VEGF-D. The downregulation of VEGF-C and -D was caused by inhibition of p38 and extracellular signal-regulated kinase (ERK)1/2, respectively. Melanoma inhibitory activity 2 was co-precipitated with integrin α4 andα5 in HSC3 cells. Integrin α4 knockdown decreased p38 phosphorylation and increased apoptosis, whereas integrin α5 knockdown decreased c-Jun N-terminal kinase (JNK) phosphorylation and apoptosis. Inhibition of JNK decreased apoptosis in the HSC3 cells.

CONCLUSION

These findings suggest that the roles of MIA2 might be based on the variety of the integrins and the subtypes of mitogen-activated protein kinase.

Tropomyosin receptor kinases B and C are tumor progressive and metastatic marker in colorectal carcinoma

Members of the tropomyosin receptor kinase (Trk) family have a high affinity for neurotrophins and regulate neuronal survival. The role of Trks in cancer is still controversial. The expression and role of TrkB and TrkC were examined in colorectal cancer (CRC). Immunohistochemical analysis of TrkB and TrkC was performed in 133 patients with CRC. Using human CRC cell lines, expression of vascular endothelial growth factor (VEGF) and transforming growth factor β, cell growth, invasion, and apoptosis were examined by knockdown methods. Immunohistochemistry showed positive results of TrkB and TrkC (23.3% and 12.8%, respectively). TrkB expression was associated with local progression (P = .0284), clinical stage (P = .0026), nodal metastasis (P = .0068), and peritoneal metastasis (P = .0026). TrkC expression was only related to liver metastasis (P = .0001). Coexpression of TrkB or TrkC and their ligands was found in 80.6% and 82.4% of cases, respectively. In vitro analysis using human CRC cells showed that TrkB positively regulated gene expression of VEGF-A (P < .05) and VEGF-C (P < .05), whereas TrkC suppressed transforming growth factor β expression (P < .05). TrkB and TrkC induced cell growth (P < .05) and invasion (P < .05), respectively. Both TrkB and TrkC showed antiapoptotic effect (P < .05). These results suggest that TrkB and TrkC have a tumor progressive function and may be a useful diagnostic and therapeutic target in CRC.

High mobility group box 1 released from necrotic cells enhances regrowth and metastasis of cancer cells that have survived chemotherapy

The role of the high mobility group box 1 (HMGB1) protein in chemotherapy-induced cell death was examined. CT26 mouse colon cancer cells were treated with trichostatin A (TSA; apoptosis inducer) or doxorubicin (DXR; necrosis inducer). DXR increased HMGB1 concentration in CT26 cell culture medium, whereas TSA did not. In a CT26 bilateral subcutaneous tumour model, DXR or TSA was injected in a single tumour. After injection, serum HMGB1 concentration in DXR-treated mice was 10 times higher than that in TSA-treated mice. After DXR treatment, the contralateral and remnant tumours showed more pronounced growth than did those treated with TSA. In mouse models, lung and liver metastasis was enhanced by DXR but not by TSA. DXR-enhanced metastasis was abrogated by anti-HMGB1 antibody treatment. In a cancer dormancy model, DXR induced regrowth of quiescent CT26 cells. HMGB1 induced tumour necrosis factor-α secretion via Toll-like receptor (TLR)4 in U937 monocytes; however, HMGB1 decreased the number of U937 cells, resulting in restriction of immune activation via receptor for advanced glycation endproducts (RAGE). RAGE showed a more pronounced effect on nuclear factor kappa B activation than did TLR4 in CT26 cells. These findings suggest that HMGB1 released from necrotic cancer cells treated with a necrosis inducer enhances regrowth and metastasis of remnant cancer cells via RAGE activation.

Trks are novel oncogenes involved in the induction of neovascularization, tumor progression, and nodal metastasis in oral squamous cell carcinoma

The function of tropomyosin receptor kinase (Trk) family including TrkA, TrkB, and TrkC in cancer remains unknown. The role of Trks in oral squamous cell carcinoma (OSCC) was examined. Knockdown of Trks provided inhibition of growth or invasion and decrease of apoptosis in OSCC cells, which expressed Trks at high levels. VEGF expression was associated with TrkA and TrkB expression; a decrease of VEGF-C and VEGF-D was observed in OSCC cells with TrkB knockdown. TrkC did not affect the expression of VEGF family. An immunohistochemical analysis of 102 OSCCs showed that TrkB expression was related to microvessel density (MVD), lymph vessel density (LVD), and poor prognosis. TrkC expression was correlated with clinical stage, lymph node metastasis, MVD, LVD, and poor prognosis. TrkA expression was associated with VEGF expression, whereas TrkB expression was associated with the expressions of VEGF, VEGF-C and VEGF-D. No significant association was found between the expression of TrkC and genes of the VEGF family. Expression of Trks was not associated with RUNX3 silencing by methylation in OSCC cells. Trks expression was inversely correlated with RUNX3 expression in the OSCC cases. These results suggested that Trks enhances progression of OSCC through angiogenesis and lymphangiogenesis.

Diabetes-associated angiotensin activation enhances liver metastasis of colon cancer

We examined the effects of hyperglycemic conditions on liver metastasis of colorectal cancer (CRC). Angiotensin (A)-II increased growth, invasion, and anti-apoptotic survival in HT29 and CT26 cells. In contrast, angiotensinogen (ATG) increased these features in HT29 cells but not in CT26 cells. HT29 cells expressed A-II type 1 receptor, chymase, and rennin, whereas CT26 cells did not express renin. Renin expression and ATG-induced cell growth, invasion, and survival induced and increased as glucose concentration increased in HT29 cells and also CT26 cells. An inhibitor of renin or chymase abrogated A-II production in HT29 cells. Reduction of hepatic ATG production by cholesterol-conjugated antisense S-oligodeoxynucleotide suppressed liver metastasis of HT29 cells. An examination of 121 CRC patients showed that diabetes in CRC cases was associated with higher blood HbA1c, higher renin and A-II concentrations in the primary tumors, and higher incidence of liver metastasis than in nondiabetic cases. These results suggest that diabetes-associated angiotensin activation enhances liver metastasis of CRC and may therefore provide a possible target for antimetastatic therapy in CRC.

The roles of HMGB1 related angiogenesis and lymphangiogenesis in oral cancer

Angiogenesis and lymphangiogenesis are the vital factors in tumor progression and metastasis. In this review, we show that high-mobility group box 1 (HMGB1) is responsible for both angiogenesis and lymphangiogenesis in oral squamous cell carcinoma (OSCC). HMGB1 possesses the dual role as a cytokine and as a chromatin protein. HMGB1 as a cytokine is the ligand of receptor for advanced glycation end products (RAGE). RAGE activation upregulates secretion of vascular endothelial growth factor (VEGF). Then co-expression of HMGB1 and RAGE accelerates angiogenesis. In contrast, nuclear HMGB1 transcriptionally induces the expression of melanoma inhibitory activity (MIA) gene with NFkB. MIA upregulates expression of VEGF-C and VEGF-D via p38 phosphorylation by integrin activation. Then HMGB1 and MIA is associated with lymphangiogenesis. According to the differential roles of HMGB1 on angiogenesis and lymphangiogenesis, local invasion, disease recurrence, and poor prognosis are associated with HMGB1–RAGE system, whereas lymph node metastasis is associated with HMGB1–MIA system in OSCC.

The roles of HMGB1 related angiogenesis and lymphangiogenesis in oral cancer

Angiogenesis and lymphangiogenesis are the vital factors in tumor progression and metastasis. In this review, we show that high-mobility group box 1 (HMGB1) is responsible for both angiogenesis and lymphangiogenesis in oral squamous cell carcinoma (OSCC). HMGB1 possesses the dual role as a cytokine and as a chromatin protein. HMGB1 as a cytokine is the ligand of receptor for advanced glycation end products (RAGE). RAGE activation upregulates secretion of vascular endothelial growth factor (VEGF). Then co-expression of HMGB1 and RAGE accelerates angiogenesis. In contrast, nuclear HMGB1 transcriptionally induces the expression of melanoma inhibitory activity (MIA) gene with NFkB. MIA upregulates expression of VEGF-C and VEGF-D via p38 phosphorylation by integrin activation. Then HMGB1 and MIA is associated with lymphangiogenesis. According to the differential roles of HMGB1 on angiogenesis and lymphangiogenesis, local invasion, disease recurrence, and poor prognosis are associated with HMGB1–RAGE system, whereas lymph node metastasis is associated with HMGB1–MIA system in OSCC.

Involvement of HMGB1 and RAGE in IL-1β-induced gingival inflammation

OBJECTIVE

Extracellularly released high mobility group box 1 (HMGB1) protein behaves as a cytokine, promotes inflammation and participates in the pathogenesis of several disorders in peripheral organs. The role of HMGB1 and receptor for advanced glycation end products (RAGE) expressed in gingival inflammatory tissues was explored.

METHODS

Real time PCR was applied to assay HMGB1 and RAGE mRNA expression in gingival epithelial and fibroblast cells induced by interleukin-1β (IL-1β). A highly selective inhibitor of inducible nitric oxide (iNOS) was employed. ELISA was done for measurement of HMGB1 concentrations in cell culture media of gingival epithelial and fibroblast cells. Immunohistochemistry was performed to analyse the expression and sub-cellular localization of HMGB1, together with RAGE, in specimens obtained from patients with chronic inflammation.

RESULTS

A time-dependent response of HMGB1 and RAGE expression in gingival cells to IL-1β induction was observed. IL-1β promotes HMGB1 production in human gingival epithelial cells in a nitric oxide-dependent manner. HMGB1 and RAGE appeared highly expressed in gingival inflammatory tissues.

CONCLUSION

These results demonstrate that HMGB1 and RAGE are abundantly expressed in gingiva and promptly released during gingival inflammation. We suggest a role for HMGB1/RAGE/iNOS signalling on inflamed gingival epithelial cells.

Anti-angiotensin and hypoglycemic treatments suppress liver metastasis of colon cancer cells

The effect of diabetic conditions on liver metastasis was examined using CT26 mouse colon cancer cells. CT26 cells produced angiotensin (A)-I and A-II from angiotensinogen; the production was abrogated by inhibitors of renin and chymase. Renin expression and A-II production increased with an increase in the concentration of glucose in the medium. In a streptozotocin-induced BALB/c mouse diabetes model that was fed a high-calorie diet, the blood sugar level increased and was associated with an increasing size and number of CT26 liver metastases. In this diabetic mouse model, liver metastasis of CT26 cells was suppressed by anti-angiotensin treatment with a chymase inhibitor, a renin inhibitor, and an A-II receptor blocker. Moreover, concurrent hypoglycemic and anti-angiotensin treatments showed a synergistic inhibitory effect on CT26 cell liver metastasis. These results suggest that angiotensin activation ability associated with diabetic conditions enhances liver metastasis of colon cancer. Therefore, treatment with anti-angiotensin and hypoglycemic agents might be relevant for baseline management of colon cancer patients with the diabetic condition for the prevention of liver metastasis. This scheme needs to be examined in a clinical setting.

Basic helix-loop-helix transcription factor DEC1 negatively regulates cyclin D1

DEC1 (also known as Stra13/Bhlhb2/Sharp2) and DEC2 (also known as Bhlhb3/Sharp1) are two paralogous basic helix-loop-helix (bHLH) transcriptional regulators which exhibit a robust circadian gene expression pattern in the suprachiasmatic nucleus (SCN) and in peripheral organs. DEC1 has been suggested to play key roles in mammalian cell differentiation, the cell cycle and circadian regulation, hypoxia response, and carcinogenesis. Here we show that DEC1 overexpression exhibits delayed wound healing and reduces cell proliferation, migration, and invasion. DEC1 strongly repressed the promoter activity of cyclin D1. We further identify a possible DEC-response element in the cyclin D1 promoter region, and confirmed the direct binding of DEC1 to that element. Forced expression of DEC1 efficiently repressed the cyclin D1 promoter and expression. Our clinical data provide the first evidence that there is a strong inverse correlation between DEC1 and cyclin D1 expression in oral cancer, and DEC1 expression significantly correlated with clinicopathological parameters. We suggest that radiation-induced DEC1 overexpression and Akt phosphorylation in cancer cells are mediated via PI-3K signalling. Overexpression of DEC1 activates the PI-3K/Akt signalling pathway through reactive oxygen species (ROS).

Abstract 3784: HMGB1 affects plasma amino acid profiles in colon carcinogenesis

Alteration of the plasma free amino acid profile was reported to be a potential marker of colorectal cancer and breast cancer. The plasma amino acid profile has been reported as a relevant marker for early detection of colorectal cancer (Okamoto N et al. Int J Med Med Sci, 2009). In the present study, we examined the plasma amino acid profile as a marker for evaluating colon cancer risk. The amino acid profiles were examined in the mouse plasma using DMH-induced C57BL6 mouse colon carcinogenesis model. The plasma amino acid profiles of DMH-treated mice were different from that in control mice. Importantly, the plasma amino acid profile at procarcinogenic phase was also distinguished from the control. We focused on HMGB1, which was timely increased in serum and colon mucosa of the DMH-treated mice. In HMGB1-adeministrated mice, the plasma amino acid profiles showed a resemble pattern with that in the procarcinogenic phase mice. Decrease of most amino acids in the liver and skeletal muscle suggested an increase of catabolism in HMGB1-treated mice. In the mouse liver and muscle tissues, HMGB1 decreased pyruvate kinase M1 expression, and tetrazolium desoxydation, whereas lactate production was not increased. HMGB1 decreased phosphorylation levels of mTOR and increased protein levels of Beclin1 and LC3 in mouse liver and muscle tissue, whereas a mitochondrial marker, Diablo was not affected. Inhibitor of p38 MAPK abrogated HMGB1-induced autophagy signals. These findings suggest that HMGB1 affects energy production in mitochondria and activates autophagy signals, which might induce protein degradation and subsequent alteration of plasma amino acid profiles. The change of the plasma amino acid profiles might be a key finding detecting procarcinogenic status of the colon.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3784. doi:10.1158/1538-7445.AM2011-3784

[A case of advanced upper gingival carcinoma responding completely to concurrent chemoradiotherapy with S-1]

We report a case of advanced upper gingival carcinoma with a contralateral metastatic lymph node invading the maxillary sinus (T4aN2cM0). An 83-year-old man was treated concurrently with chemoradiotherapy and S-1. S-1 (80 mg/body/day) was administered for 2 weeks followed by a 1-week rest period as one course. Radiation therapy involved a total of 60 Gy (2 Gy/day; 5 days/week). There were side effects of mild leucopenia and a grade 2 stomatitis. After the completion of 2 courses and radiation therapy, the primary tumor disappeared, and the patient achieved a pathologically complete response. The metastatic lymph node also completely disappeared. S-1 was then administered in the same regimen for 1 year. Neither local recurrence nor distant metastasis has been detected 2 years after the completion of the concurrent chemoradiotherapy with S-1.

Determinants of the epithelial-muscular axis on embryonic stem cell-derived gut-like structures

Dome-like structures with epithelial-muscular layers resembling the gut have been derived from mouse embryonic stem (ES) cells. These domes have been reported to show spontaneous contractions and are called ES gut. In the present study, we examined the epithelial-muscular axis of these domes by detecting differentiation markers. A normal epithelial-muscular axis was exhibited in the domes with spontaneous motility, whereas the domes without spontaneous motility showed either an inverted or obscure axis. To investigate the factors affecting the epithelial-muscular axis, we examined the expression of hedgehog signaling factors in the domes. Expression of hedgehog family factors was detected in the epithelial components of the domes with motility, whereas this expression was inverted or obscure in the domes without motility. Out of the 25 domes, 10 of the 10 motility (+) domes showed a normal epithelial-muscular axis, whereas 14 of the 15 motility (-) domes lacked a normal epithelial-muscular axis. This implies that activin A upregulated the expression of sonic hedgehog and intestinal alkaline phosphatase in the embryoid bodies. These findings suggest that the motility of the ES gut depends on the domes' epithelial-muscular axis.

Downregulation of runt-related transcription factor 3 associated with poor prognosis of adenoid cystic and mucoepidermoid carcinomas of the salivary gland

Runt-related transcription factor 3 (RUNX3) is a transcription factor of the transforming growth factor (TGF)-β superfamily and acts as a tumor suppressor gene, which is silenced by hypermethylation of the promoter region in various cancers. In this study, we examined the expression and methylation status of RUNX3 in the salivary gland cancers pleomorphic adenoma (PA), adenoid cystic carcinoma (ACC) and mucoepidermoid carcinoma (MEC). The cytoplasmic expression rates of RUNX3 in PA, ACC and MEC were 65% (13/20), 22.2% (8/36) and 20.6% (7/34), respectively. Low expression or deletion of RUNX3 in ACC and MEC was significantly associated with tumor progression and poor prognosis. Using microdissected cDNA, we found that RUNX3 mRNA expression was lower in ACC and MEC than in PA and noncancerous salivary glands; furthermore, hypermethylation of RUNX3 was detected more frequently in PA (2/8, 25%), ACC (6/8, 75%) and MEC (7/8, 87.5%) than in noncancerous salivary glands (0/8, 0%). Our results suggest that low expression or deletion of RUNX3 in salivary gland tumors might play a pivotal role in tumorigenesis and tumor progression and poor prognosis in the case of salivary gland ACC and MEC. Recovery of the tumor suppressive function of RUNX3 might inhibit tumorigenesis and cancer progression in the human salivary gland.

Dietary linoleic acid and glucose enhances azoxymethane-induced colon cancer and metastases via the expression of high-mobility group box 1

OBJECTIVE

High-mobility group box 1 (HMGB1) was closely associated with progression and metastasis of colorectal cancer.

METHODS

We examined the significance of HMGB1 in causing colon carcinogenesis induced by azoxymethane (AOM) injection in Fischer 344 rats fed on a control diet (group C), a 15% linoleic acid (LA) diet (group L), a control diet with 10% glucose drink (group G), and a 15% LA diet with a 10% glucose drink (group L+G).

RESULTS

Group L+G showed the highest body weight and calorie intake. Serum and mucosal HMGB1 levels were temporally increased in all groups, while the highest levels were observed in group L+G. Mucosal HMGB1 levels were correlated with cancer multiplicity and nodal metastases. In the AOM-injected rats fed the 15% LA diet with 10% glucose drink, administration of HMGB1 antibody suppressed serum HMGB1 concentration and cancer multiplicity.

CONCLUSION

These data suggest that dietary LA and glucose provided the synergistic effect on AOM-induced rat colon cancer through HMGB1 induction.

Abstract 2365: Cancer cell necrosis induces tumor growth by releasing HMGB1

HMGB1 secreted from cancer cells accelerates invasion and metastasis of them. HMGB1 is released from necrotic cells. In the present study, we examined the differential effect on HMGB1 of apoptosis inducer (AI) from necrosis inducer (NI). CT26 mouse colon cancer cells were treated with trichostatin A (TSA) as AI or doxorubicin (DXR) as NI. DXR treatment increased HMGB1 in cultured medium (CM), whereas TSA did not increase. DXR-treated CM accelerated cell growth and invasion, whereas TSA-treated CM did not accelerate. CT26 cells were inoculated in the bilateral dorsal subcutaneous tissues of mice, which were treated with DXR or TSA by intratumoral injection. After treatment, serum HMGB1 concentrations by DXR and TSA treatments were 228 ng/ml and 21 ng/ml, respectively. After DXR treatment, contralateral tumor and the remnant tumor showed more pronounced growth or re-growth than those treated with TSA. By the lung metastasis model by caudal vein inoculation and the liver metastasis model by intrasplenic inoculation of CT26 cells, lung and liver metastasis was more enhanced by DXR treatment than those by TSA treatment. Metastasis enhancement by DXR treatment was abrogated by anti-HMGB1 co-treatment. Re-growth of linoleic acid-induced quiescent cells was found in DXR-treated mice but not in TSA-treated mice. These finding suggest that HMGB1 released from necrotic cancer cells treated with NI might enhance re-growth and metastasis of remnant cancer cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2365.

CD10 enhances metastasis of colorectal cancer by abrogating the anti-tumoural effect of methionine-enkephalin in the liver

OBJECTIVE

To examine the role of CD10, a characteristic marker of liver metastasis of colorectal cancers (CRCs).

DESIGN

The effect of CD10 and Met-enkephalin (MENK) in CD10-positive and -negative human CRC cells was investigated under in vitro and in vivo conditions. Human CRC samples were examined.

MAIN OUTCOME MEASURE

CD10-positive and CD10-knockdown HT29 cells and CD10-negative and CD10-transfected Colo320 cells in nude mice were treated with MENK and/or the CD10 inhibitor (thiorphan). Intracellular signalling of MENK and delta-opioid receptor (DOR) was examined by immunoblotting.

RESULTS

MENK inhibited the growth, invasion and survival of CRC cells following thiorphan-induced CD10 inactivation. Thiorphan suppressed liver metastasis of CD10-positive CRC cells. Inoculation of mice with CRC cells induced MENK expression in the liver. Inhibition of hepatic MENK expression by cholesterol-conjugated antisense S-oligodeoxynucleotide increased liver metastasis of CRC cells even when the cells did not express CD10. DOR activation by MENK decreased the phosphorylation of epidermal growth factor receptor and extracellular signal-regulated kinase and increased p38-dependent apoptosis. Nitric oxide was found to induce DOR expression in CRC cells. Co-treatment with thiorphan and a nitric oxide donor had a marked anti-tumour effect on liver metastasis of HT29 cells. Of 68 CRC patients, 19 (28%) showed CD10 expression, which was dependent on the extent of liver metastasis. MENK concentration in metastasis-positive human liver was higher than that in the normal liver.

CONCLUSION

CD10 expression in CRC cells abrogates the anti-tumour effect of hepatic MENK by degrading it, which enhances liver metastasis of CD10-positive CRC cells.

HMGB1 attenuates anti-metastatic defense of the lymph nodes in colorectal cancer

BACKGROUND

Cancer-secreted high mobility group 1 (HMGB1) induces apoptosis of macrophages and suppresses the host anti-cancer immune system.

OBJECTIVE

We here examined the effect of HMGB1 on macrophages in the lymph nodes of colorectal cancer (CRC) patients.

METHODS

Regional lymph nodes of 50 Dukes C CRCs were compared with 50 Dukes B CRCs.

RESULTS

Dukes C tumors exhibited higher HMGB1 labeling indices and higher HMGB1 concentrations in primary tumors than Dukes B CRCs. Macrophages in the regional lymph nodes were decreased in non-metastasized nodes as well as metastasized nodes in Dukes C cases, whereas macrophage numbers in Dukes B nodes were higher than in Dukes C nodes. Nodal HMGB1 concentration was higher in Dukes C nodes than in Dukes B nodes, being inversely correlated with macrophage numbers. Nodal HMGB1 concentration was correlated with HMGB1 concentration and lymph vessel density in the primary tumors.

CONCLUSION

These data suggest that HMGB1 secreted from primary tumors spread to the regional lymph nodes decreases the number of macrophages to attenuate the anti-metastatic defense of the lymph nodes in patients with CRCs.

HMGB1 attenuates anti-metastatic defence of the liver in colorectal cancer

High mobility group box (HMGB) 1 induces apoptosis of monocyte-lineage cells. We examined the effect of HMGB1 on Kupffer cells (KCs). In 50 Dukes C and 12 liver-metastasised Dukes D colorectal cancers (CRCs), higher HMGB1 concentration in the primary tumours and metastatic foci, and fewer KCs were found in Dukes D cases than in Dukes C cases. The portal blood HMGB1 concentration was higher in Dukes D cases than in Dukes C cases. HMGB1 induced growth inhibition and apoptosis in mouse KCs in a dose-dependent manner, which was associated with the phosphorylation of c-Jun N-terminal kinase (JNK). JNK inhibition and knockdown of HMGB1 receptor abrogated growth inhibition and apoptosis. In a nude mouse liver metastasis model, the caecal administration of HMGB1 decreased the number of KCs and increased the embedment of Colo320 CRC cells in a dose-dependent manner. HMGB1 transfection increased the liver metastasis of Colo320 cells, and the metastasis was inhibited by anti-HMGB1 antibody administration. These results suggest that HMGB1 secreted from primary tumours decreases the number of KCs and attenuates the anti-metastatic defence of the liver in patients with CRCs.

Antisense phosphorothioate oligodeoxynucleic acid for CD10 suppresses liver metastasis of colorectal cancer

CD10 expression is associated with metastases of colorectal cancer (CRC). In the present study, we examined association of CD10 with liver metastasis of CRC cells to clarify the therapeutic significance of CD10. CD10-positive human colon cancer cell line, HT29 cells showed inhibition of growth, invasion and colony formation by treatment with CD10 antisense S-oligodeoxynucleotide (S-ODN). In the mouse liver metastasis mode, CD10 antisense S-ODN-treated HT29 cells made less embedded cells in the liver than control HT29 cells. Number and size of metastatic foci in nude mice liver were reduced in CD10 antisense S-ODN-treated HT29 cells. Treatment with CD10 antisense S-ODN decreased phosphorylation of ERK1/2 and EGFR in HT29 cells. Intraperitoneal administration of liposome-capsulated CD10 antisense S-ODN inhibited establishment of liver metastasis and growth of established metastasis in nude mice. These findings suggest that CD10 is associated substantially with liver metastasis of CRC cells and might be a molecular target of CRC treatment.

Co-treatment with deoxycholic acid and azoxymethane accelerates secretion of HMGB1 in IEC6 intestinal epithelial cells

OBJECTIVES

High-mobility group box 1 (HMGB1) is a nuclear protein that acts as a ligand of the receptor for advanced glycation end products (RAGE) and its expression enhances progression of cancer. However, the mechanism underlying HMGB1 secretion is still unclear. In this study, we examined the effect of deoxycholic acid (DCA), a promoter of colon carcinogenesis, on HMGB1 secretion.

MATERIALS AND METHODS

We used an in vitro transformation model comprised of IEC6 intestinal epithelial cells treated with azoxymethane (AOM) and/or DCA. HMGB1 expression and secretion were examined by Western and Northern blot analyses, and ELISA. Intracellular translocation of HMGB1 was examined by protein fractionation.

RESULTS

AOM + DCA-treated IEC6 cells showed upregulation of HMGB1 mRNA expression and increased level of HMGB1 protein in culture medium, but decreased level of HMGB1 protein in the nucleus. AOM + DCA treatment increased level of histone H4 acetylation, which induced translocation of HMGB1 from the nucleus to the cytoplasm and increased HMGB1 secretion. Leptomycin B inhibited extranuclear translocation and secretion of the HMGB1 protein.

CONCLUSION

These findings suggest that DCA affects intracellular localization and secretion of HMGB1.

Suppression of dendritic cells by HMGB1 is associated with lymph node metastasis of human colon cancer

High mobility groupbox-1 (HMGB1) is a multifunctional cytokine secreted by cancer cells, which accelerates cell growth, invasion and angiogenesis in cancer, and induces apoptosis in macrophages. Thioglycolate-stimulated mouse peritoneal macrophages were induced to differentiate into dendritic cells by co-treatment with IL-4 and GM-CSF. The number of mouse peritoneal macrophage-derived dendritic cells (PMDDCs) showed a dose-dependent decrease in hrHMGB1 treatment. HMGB1-treated PMDDCs showed obvious apoptosis and increased the level of phosphorylated JNK. Intraperitoneal administration of HMGB1 decreased CD205-positive splenic dendritic cells in C57BL mice. To confirm the HMGB1-induced inhibitory effect on dendritic cells, 16 cases of human colon cancer invaded into the subserosal layer were examined. The 8 nodal metastasis-positive cases showed higher nodal HMGB1 concentrations (74 +/- 23 vs. 41 +/- 15 microg/ml, p = 0.0116) in lymph node tissues and lower CD205-positive nodal dendritic cell numbers (86 +/- 22 vs. 137 +/- 43/mm(2), p = 0.0224) than those in the 8 metastasis-negative cases. Primary tumor tissues of metastasis-positive cases showed higher tumor HMGB1 levels (116 +/- 33 vs. 37 +/- 18 microg/ml, p = 0.0007) and lower CD205-positive intratumoral dendritic cell numbers (21 +/- 13 vs. 62 +/- 23 /mm(2), p = 0.0068) than those in metastasis-negative cases. These findings suggest that HMGB1 produced by colon cancer cells suppressed nodal dendritic cells to disturb host anti-cancer immunity.