Genetic Analyses of Primary Liver Cancer Cell Lines: Correspondence With Morphological Features of Original Tumors

BACKGROUND/AIM

Advancements in genetic analysis technologies have led to establishment of molecular classifications systems for primary liver cancers. The correlation between pathological morphology and genetic mutations in hepatocellular carcinoma (HCC) is becoming increasingly evident. To construct appropriate experimental models, it is crucial to select cell lines based on their morphology and genetic mutations. In this study, we conducted comprehensive genetic analyses of primary liver cancer cell lines and examined their correlations with morphology.

MATERIALS AND METHODS

Thirteen primary liver cancer cell lines established in our Department were investigated. Eleven cell lines were HCC cell lines, whereas 2 were combined hepatocellular-cholangiocarcinoma (CHC) cell line characteristics. Whole exome sequencing and fusion gene analyses were conducted using a next generation sequencing platform. We also examined correlations between cell mutations and morphological findings and conducted experiments to clarify the association between morphological findings and genetic alterations.

RESULTS

Mutations in TP53, HMCN1, PCLO, HYDIN, APOB, and EYS were found in 11, 5, 4, 4, 3, and 3 cell lines, respectively. CTNNB1 mutation was not identified in any cell line. The original tumor of four cell lines (KYN-1, KYN-2, KYN-3, and HAK-6) showed morphologically macrotrabecular massive patterns and these cell lines harbor TP53 mutations. Two cell lines (KYN-2 and KMCH-2) showed an extremely high tumor mutation burden. These two cell lines possess ultra-mutations associated with DNA repair and/or DNA polymerase.

CONCLUSION

The study identified correlations between morphological findings and genetic mutations in several HCC cell lines. Cell lines with unique genetic mutations were found. This information will be a valuable tool for the selection of suitable experimental models in HCC research.

Soluble Immune Checkpoint Molecules as Predictors of Efficacy in Immuno-Oncology Combination Therapy in Advanced Renal Cell Carcinoma

Immuno-oncology (IO) combination therapy is the first-line treatment for advanced renal cell carcinoma (RCC). However, biomarkers for predicting the response to IO combination therapy are lacking. Here, we investigated the association between the expression of soluble immune checkpoint molecules and the therapeutic efficacy of IO combination therapy in advanced RCC. The expression of soluble programmed cell death-1 (sPD-1), soluble programmed cell death ligand-1 (sPD-L1), soluble PD-L2 (sPD-L2), and lymphocyte activation gene-3 (sLAG-3) was assessed in plasma samples from 42 patients with advanced RCC who received first-line IO combination therapy. All IMDC risk classifications were represented among the patients, including 14.3, 57.1, and 28.6% with favorable, intermediate, and poor risk, respectively. Univariate analysis revealed that prior nephrectomy, sPD-L2 levels, and sLAG-3 levels were significant factors affecting progression-free survival (PFS), whereas multivariate analyses suggested that sPD-L2 and sLAG-3 levels were independent prognostic factors for PFS. In a univariate analysis of the overall survival, prior nephrectomy and sPD-L2 levels were significant factors; no significant differences were observed in the multivariate analysis. No significant correlation was observed between the sPD-L2 and sLAG-3 levels and PD-L2 and LAG-3 expression via immunohistochemistry. In conclusion, sPD-L2 and sLAG-3 expression may serve as a potential biomarker for predicting IO combination therapy efficacy.

Immunophenotypes and Tumor Immune Microenvironment in Hepatocellular Carcinoma With Macrotrabecular Massive and Vessels Encapsulating Tumor Clusters

BACKGROUND/AIM

Recently, vessels encapsulating tumor clusters (VETC) pattern and macrotrabecular massive (MTM) pattern of hepatocellular carcinoma (HCC) have been reported as aggressive histological types. These histological patterns showed an immunosuppressive tumor immune microenvironment (TIME). Since there have been no reports on the differences of these two subtypes simultaneously, this study examined the immunophenotypes and TIME of MTM-HCC and VETC-HCC immunohistochemically.

PATIENTS AND METHODS

Seventy-four cases of previously diagnosed HCC, including 32 MTM-HCCs, 21 VETC-HCCs, and 21 conventional HCCs, were enrolled in immunohistochemical analysis. We conducted immunohistochemical analysis.

RESULTS

We found that MTM-HCC showed less frequent expression of HepPar-1, which is one of the most common hepatocytic markers. In MTM-HCC, the frequency of high expression levels of Keratin19, carbonic anhydrase (CA) IX, and PD-L1 was higher compared to VETC-HCC and conventional HCC. PD-L1 expression was found in 34.4% of MTM-HCC, 0% of VETC-HCC, and 19.0% of conventional HCC. The rate of PD-L1 expression in MTM-HCC was significantly higher than the others (p=0.0015). PD-L1 expression was significantly associated with epithelial cell adhesion molecules and CA IX expression, which are representative markers of tumor stemness and hypoxic conditions, respectively. The CD8 infiltration in VETC-HCC was significantly lower than that in conventional HCC.

CONCLUSION

MTM-HCC had different immunophenotypes and TIMEs compared to HCC with the VETC pattern. Although both had immunosuppressive TIME, the elements forming TIME were quite different. To enhance the immune checkpoint inhibitor efficacy, changing TIME from a suppressive to an active form is essential.

Clinicopathological characteristics and molecular analysis of lymphocyte-rich hepatocellular carcinoma

Lymphocyte-rich hepatocellular carcinoma (LR-HCC), a newly proposed subtype of HCC, is characterized with abundant lymphocyte infiltration in the tumor. LR-HCC has a relatively good prognosis and is quite rare (<1% of all HCC). We examined LR-HCC clinicopathological and molecular characteristics by analyzing 451 surgically resected HCC cases without any prior treatment history at our hospital between 2012 and 2021. Clinicopathological features of LR-HCC and other HCCs (non-LR-HCC) were compared. Neoplastic and nonneoplastic hepatocytes from LR-HCC (n = 4) were collected with a laser microdissection system; RNA was extracted, followed by microarray analysis to examine lymphocytic infiltration-related molecular targets. Immunohistochemical staining of identified molecular target was performed in LR-HCC and non-LR-HCC. CD3, CD20, and CD8 immunostaining was also performed in LR-HCCs. There were 28 cases of LR-HCC (6%). No statistically significant differences were found in clinicopathological features, except for gross type, between LR-HCC and non-LR-HCC cases. The LR-HCC 5-year survival rate was >90%. Microarray analysis revealed high CCL20 expression in LR-HCC cases; immunohistochemical study showed significantly higher CCL20 expression in LR-HCC (P < 0.01) than in non-LR-HCC. CCR6, the only CCL20 receptor, was observed in infiltrating lymphocytes and HCC cells in LR-HCC. There were significantly more CD3-positive cells than CD20-positive cells (P < 0.0001) in tumor-infiltrating lymphocytes, most of which were CD8-positive T cells. In conclusion, there were no significant differences in clinicopathological characteristics between LR-HCC and non-LR-HCC, except for gross and LR microscopic features. CCL20 expression in LR-HCC may contribute to infiltration of large numbers of CD8-positive lymphocytes.

Prediction Model with HLA-A*33:03 Reveals Number of Days to Develop Liver Cancer from Blood Test

The development of liver cancer in patients with hepatitis B is a major problem, and several models have been reported to predict the development of liver cancer. However, no predictive model involving human genetic factors has been reported to date. For the items incorporated in the prediction model reported so far, we selected items that were significant in predicting liver carcinogenesis in Japanese patients with hepatitis B and constructed a prediction model of liver carcinogenesis by the Cox proportional hazard model with the addition of Human Leukocyte Antigen (HLA) genotypes. The model, which included four items-sex, age at the time of examination, alpha-fetoprotein level (log₁₀AFP) and presence or absence of HLA-A*33:03-revealed an area under the receiver operating characteristic curve (AUROC) of 0.862 for HCC prediction within 1 year and an AUROC of 0.863 within 3 years. A 1000 repeated validation test resulted in a C-index of 0.75 or higher, or sensitivity of 0.70 or higher, indicating that this predictive model can distinguish those at high risk of developing liver cancer within a few years with high accuracy. The prediction model constructed in this study, which can distinguish between chronic hepatitis B patients who develop hepatocellular carcinoma (HCC) early and those who develop HCC late or not, is clinically meaningful.

Transcription factor activating enhancer-binding protein 2B expression correlates with invasiveness and prognosis of extramammary Paget's disease

BACKGROUND

Extramammary Paget's disease (EMPD) is a slowly advancing malignancy that sometimes progresses to the invasion of the dermis, systemic metastases, and death. Although there have been reports that dermal invasion is associated with poor prognosis, no molecular markers of this invasion have been identified thus far. The aim of this study was to identify key molecules for predicting the risk of EMPD dermis invasion.

METHOD

We performed microarray screening for three cases of in-situ EMPDs, three cases of invasive EMPDs, and three cases of normal epidermis. We identified a molecule that exhibited a stepwise increase in expression. Further, we analyzed 47 cases of EMPD using immunohistochemical staining (IHC) and examined the correlated clinicopathological findings, including prognosis.

RESULT

We examined molecules that showed stepwise differences with invasion. We focused on transcription factor activating enhancer-binding protein 2 B (TFAP2B). Of the 47 EMPD patients, 38 (80.9 %) and 9 (19.1 %) had low and high TFAP2B expression, respectively. TFAP2B expression was significantly correlated with invasion into the dermis, mass formation, and preoperative lymph node metastasis (p = 0.001, 0.042, and 0.033, respectively). The cumulative postoperative recurrence-free rate in the TFAP2B-high expression group was significantly lower than that in the TFAP2B-low expression group (P < 0.001). In univariate analysis of recurrence-free survival, TFAP2B expression was found to be a significant factor (p = 0.006).

CONCLUSION

The expression of TFAP2B, which was comprehensively found by microarray screening, may correlate with the invasiveness of EMPD and may be an unfavorable prognostic factor.

Clinicopathological Analysis of Non-B Non-C Hepatocellular Carcinoma Focusing on Cellular Proliferation

BACKGROUND/AIM

Non-B non-C hepatocellular carcinomas (NBNC-HCCs) are larger than hepatitis virus-related HCCs. We conducted a clinicopathological study of patients who underwent curative NBNC-HCC resection, including proliferative activity assessments, such as nuclear grade and Ki-67 labelling index (LI).

MATERIALS AND METHODS

Histopathological findings of 197 patients were examined, including 56 NBNC-HCCs, 45 hepatitis B virus (HBV)-related HCCs (HBV-HCC), and 96 hepatitis C virus (HCV)-related HCCs (HCV-HCC).

RESULTS

NBNC-HCCs were significantly larger than HCV-HCCs, but not significantly different from HBV-HCCs. Mitotic counts, nuclear grade, and Ki-67 LI of NBNC-HCCs were not significantly different from those of HCV-HCCs, but were significantly lower than those of HBV-HCCs. Recurrence-free survival was significantly better in the NBNC-HCC group than in the HBV-HCC group in cases with mild liver fibrosis.

CONCLUSION

NBNC-HCCs were significantly larger in diameter, but their nuclear grade or Ki-67 LI were not significantly different from those of other HCCs, suggesting that they do not have a higher proliferative activity.

Expression and significance of laminin receptor in squamous cell carcinoma of the tongue

BACKGROUND

Laminin receptor is a non-integrin cell-surface receptor that binds laminin present on the basement membrane. It has been reported to be associated with infiltration and metastasis of various malignant tumors. However, no studies regarding tongue cancer have been reported. This study aimed to clarify the role of laminin receptor in squamous cell carcinoma of the tongue.

METHODS

We performed immunohistochemical staining of specimens from 66 patients with squamous cell carcinoma of the tongue and assessed laminin receptor expression and clinicopathological factors. As epithelial-mesenchymal transition has been shown to be associated with infiltration and metastasis of malignant tumors, staining for E-cadherin, vimentin, and N-cadherin were also performed.

RESULTS

Of 20 patients with postoperative recurrence, 14 exhibited high laminin receptor expression (p = 0.0025). Kaplan-Meier analysis revealed a significantly shorter time to postoperative recurrence for the high laminin receptor expression group than that for the low laminin receptor expression group (p = 0.0008). Based on multivariate analyses for postoperative recurrence, high laminin receptor expression was associated with poor prognosis (high expression vs. low expression; HR =3.19, 95% CI =0.92-11.08; p = 0.0682). There was a correlation between laminin receptor and N-cadherin (p = 0.0089) but not between laminin receptor and E-cadherin (p = 0.369) or vimentin (p = 0.4221).

CONCLUSION

These results suggest that high laminin receptor expression is a useful prognostic factor for postoperative recurrence and may be a target for molecular therapy to treat squamous cell carcinoma of the tongue.

Programmed Death-Ligand 1 and Programmed Death-Ligand 2 Expression Can Affect Prognosis in Extramammary Paget's Disease

BACKGROUND

Extramammary Paget's disease (EMPD) is a type of carcinoma that usually progresses slowly but may cause metastasis and subsequent death of patients. We investigated the relationship between the expression of programmed death-ligand 1 (PD-L1)/programmed death-ligand 2 (PD-L2) and stromal CD8⁺ tumor-infiltrating lymphocytes (TILs) in EMPD and clinicopathological findings, including prognosis.

MATERIALS AND METHODS

We examined 47 cases of EMPD and performed immunohistochemical staining of formalin-fixed paraffin-embedded full-face sections.

RESULTS

PD-L1 expression in tumor cells was observed in 13 cases (27.7%) while PD-L2 expression was observed in 21 cases (44.7%). The cumulative postoperative recurrence-free rate in the group with positivity for PD-L1 and/or PD-L2 with a low CD8⁺ TIL count was significantly lower than that of the corresponding group with a high CD8⁺ TIL count and of the PD-L1- and PD-L2-negative group (p=0.026).

CONCLUSION

The expression of PD-L1/PD-L2 in tumor cells was shown to be a factor for poor prognosis.

Quercetin Suppresses Proliferation of Liver Cancer Cell Lines In Vitro

BACKGROUND/AIM

We investigated the anti-proliferative effect of quercetin on liver cancer cell lines.

MATERIALS AND METHODS

Thirteen liver cancer cell lines were cultured followed by treatment with varying concentrations of quercetin (0-100 μM) or quercetin and 5-FU, and the cell viability was analysed by the MTT assay. Flow cytometry was also used to examine cell cycle progression after treatment with quercetin.

RESULTS

The addition of quercetin resulted in a dose- and time-dependent suppression of cell proliferation. In some cell lines, treatment with quercetin and 5-FU caused an additional or synergistic effect. Most cell lines displayed cell cycle arrest at different phases of the cell cycle.

CONCLUSION

Quercetin inhibits the proliferation of liver cancer cells via induction of apoptosis and cell cycle arrest.

Usefulness of Tumor Tissue Biopsy for Predicting the Biological Behavior of Hepatocellular Carcinoma

BACKGROUND/AIM

Assessment of the biological behavior of tumors is important for choosing an appropriate cancer therapy. In hepatocellular carcinoma (HCC), the biological behaviour can be assessed by tumor morphology and molecular biology. This study investigated the usefulness of tumor tissue biopsy for predicting the biological behavior of HCC.

PATIENTS AND METHODS

We studied 43 patients who underwent hepatectomy and preoperative liver tumor biopsy for HCC. We performed clinicopathological and immunohistochemical (IHC) analyses. The expression of the following molecules was examined: regulator of G-protein signaling 5 (RGS5), glypican-3 (GPC3), keratin 19 (K19), epithelial cell adhesion molecule (EpCAM), protein induced by vitamin K absence or antagonist-II (PIVKA-II), β-Catenin, and p53.

RESULTS

There was an overall 83.7% agreement regarding tumor differentiation between the preoperative biopsy specimens and the resected specimens. The accuracy of IHC analysis was more than 70% for all molecules between the preoperative biopsy specimens and the resected specimens. The RGS5-positive biopsy cases had higher serum α-fetoprotein levels (p=0.04), a higher rate of moderately or poorly differentiated tumors (p=0.02) and portal vein invasion (p=0.0003) than the RGS5-negative biopsy cases. The GPC3-positive biopsy cases were younger (p=0.04), had higher serum PIVKA-II levels (p=0.01), and a higher rate of portal vein invasion (p=0.03) than the GPC3-negative biopsy cases. The PIVKA-II-positive biopsy cases had significantly higher serum PIVKA-II levels than the PIVKA-II-negative biopsy cases (p=0.02). The other molecular markers showed no significantly different clinical findings between the positive and negative cases.

CONCLUSION

In HCC, there was a high agreement rate of both the histopathological and IHC findings between preoperative biopsy specimens and resected specimens. In the biopsy specimens of HCC, RGS5 and GPC3 expression were useful molecular makers for predicting portal vein invasion. Liver tumor biopsy is useful for predicting the biological behavior of HCC through histopathological and immunohistochemical findings.

Distinctive clinicopathological features and KRAS and IDH1/2 mutation status of cholangiolocellular carcinoma

AIM

Cholangiolocellular carcinoma (CLC) is classified as a subtype of combined hepatocellular cholangiocarcinoma with stem-cell features (CHC-SC) in the latest World Health Organization classification. This subclassification of CHC-SCs is controversial and the relevance of such classification is unclear.

METHODS

We analyzed a series of CHC-SCs and intrahepatic cholangiocarcinoma (iCCA) to clarify the clinicopathological features and mutational status of each tumor.

RESULTS

Background liver disease, fibrosis stage, microvascular invasion, nodal metastasis, and IDH1/2 mutation status were associated with their histology. Compared with the intermediate cell subtype of CHC-SC (CHCs-SC-int), CLCs were less frequently associated with chronic viral hepatitis, and showed lower levels of serum alpha-fetoprotein. Compared with iCCAs, CLCs showed lower levels of serum carbohydrate antigen 19-9 (CA19-9) and a lower frequency of expression of S100P. Patients with iCCA showed worse overall survival than those with CLC or CHC-SC-int. In patients with iCCA, CLC, or CHC-SC-int, a histology of iCCA, microvascular invasion, and serum CA19-9 value of >100 U/mL were significant poor prognostic factors for overall survival in univariate analysis. Multivariate analysis showed that a high serum CA19-9 value was an independent poor prognostic factor for overall survival.

CONCLUSIONS

Patients with CLC are likely to have a different etiology and mutational background from those with CHC-SC-int. Their clinicopathological manifestations are also different from those with classic iCCA. Our results suggest that CLC might be a distinct entity among primary liver carcinomas.

Elevated Expression of EPHA2 Is Associated With Poor Prognosis After Radical Prostatectomy in Prostate Cancer

BACKGROUND/AIM

Therapeutic targeting of receptor protein tyrosine kinases (PTKs) has proven successful in treating cancer. However, reports about PTKs in treating prostate cancer are few. Elevated expression of the erythropoietin-producing hepatocellular receptor A2 (EPHA2) receptor tyrosine kinase, a transmembrane protein, is associated with poor prognosis of certain cancer types when the enzyme is dephosphorylated. This study investigated whether EPHA2 is useful in predicting the biochemical recurrence of prostate cancer.

PATIENTS AND METHODS

Data from 241 patients who had undergone total prostatectomy between 2007 and 2011 were used. EPHA2 protein expression was categorized as high or low by two pathologists. The relationship was examined between EPHA2 expression level (high vs. low) and clinicopathological factors including biochemical recurrence. Correlations were examined between EPHA2, low-molecular-weight protein tyrosine phosphatase (LMW-PTP), E-cadherin, and Ki-67.

RESULTS

EPHA2 expression was high in 121 (50.2%) and low in 120 (49.8%) patients. A log-rank test revealed early biochemical recurrence in the high-expression group. Gleason score, Ki-67 labeling index, and biochemical recurrence were more frequent in the high-expression group. Furthermore, multivariate analyses revealed that high EPHA2 expression was an independent prognostic factor for biochemical recurrence (hazard ratio=3.62, 95% confidence interval=2.39-5.61). Correlations between EPHA2 and both LMW-PTP and Ki-67 labeling index were positive, whereas EPHA2 and E-cadherin were negatively correlated.

CONCLUSION

EPHA2 overexpression is predictive of aggressive prostate cancer behavior. EPHA2 may be a powerful prognostic biomarker for decision-making in postoperative follow-up after total prostatectomy, and regarding the need for palliative treatment. Additionally, it may be an important therapeutic target.

Malic enzyme 1 is a potential marker of combined hepatocellular cholangiocarcinoma, subtype with stem-cell features, intermediate-cell type

AIM

Combined hepatocellular cholangiocarcinoma, subtype with stem-cell features, intermediate-cell subtype (INT) shows various histological appearances and could be misdiagnosed as intrahepatic cholangiocarcinoma (iCCA). In the present study, we aimed to identify specific histological diagnostic markers of INT.

METHODS

We extracted RNA from FFPE sections of six INT, five iCCA, and five hepatocellular carcinoma (HCC) cases and compared gene expression between INT, iCCA, and HCC by microarray analysis. We then undertook immunohistochemical (IHC) staining of potential key molecules identified by microarray analysis, the conventional hepatocytic marker, hepatocyte paraffin (HepPar)-1, and the cholangiocytic markers, keratin (K) 7 and K19, on 35 INT, 25 iCCA, and 60 HCC cases.

RESULTS

Microarray analysis suggested that malic enzyme 1 (ME1) was significantly upregulated in INT. Immunohistochemical analysis revealed that the positive rates of ME1 in INT, iCCA, and HCC were 77.1% (27/35), 28.0% (7/25), and 61.7% (37/60), respectively. Analysis of classification and regression trees based on IHC scores indicated that HepPar-1 could be a good candidate for discriminating HCC from the others with high sensitivity (93.3%) and high specificity (96.7%). A multiple logistic regression model and receiver operating characteristic curve analysis based on the IHC scores of ME1, K7, and K19 generated a composite score that can discriminate between INT and iCCA. Using this composite score, INT could be discriminated from iCCA with high sensitivity (88.6%) and high specificity (88.0%).

CONCLUSIONS

We propose that ME1 is a useful diagnostic marker of INT when used in combination with other hepatocytic and cholangiocytic markers.

KDM2A-dependent reduction of rRNA transcription on glucose starvation requires HP1 in cells, including triple-negative breast cancer cells

Triple-negative breast cancer (TNBC) is very aggressive and lacks specific therapeutic targets. Ribosome RNAs (rRNAs) are central components of ribosomes and transcribed in nucleoli, and the level of rRNA transcription greatly affects ribosome production and cell proliferation. We have reported that an epigenetic protein, KDM2A, exists in nucleoli and reduces rRNA transcription on glucose starvation. However, the molecular mechanism is still unclear. The purpose of this study is to examine the KDM2A-dependent regulation mechanism of rRNA transcription. In this study, we turned our attention to the nucleolar accumulation of KDM2A. We found that KDM2A had multiple regions for its nucleolar localization, and one of the regions was directly bound by heterochromatin protein 1γ (HP1γ) using valine 801 in the LxVxL motif of KDM2A. A knockdown of HP1γ or a point mutation of valine 801 in KDM2A decreased the nucleolar accumulation of KDM2A, and suppressed the reduction of rRNA transcription on glucose starvation. These results uncovered a novel function of HP1γ: the regulation of rRNA transcription, and suggested that HP1γ stimulates the nucleolar accumulation of KDM2A to support the KDM2A-dependent regulation of rRNA transcription. HP1γ was expressed in cancer cells in all breast carcinoma tissues examined, including TNBC tissues. A knockdown of HP1γ in a TNBC cell line, MDA-MB-231 cells, reduced the nucleolar accumulation of KDM2A, and suppressed the reductions of rRNA transcription and cell proliferation on glucose starvation. These results suggest that the KDM2A-dependent regulation of rRNA transcription requires HP1γ, and thus may be applicable to the treatment of TNBC.

Programmed death-ligand 1 expression is an unfavorable prognostic factor of hepatocellular carcinoma after archiving sustained virologic response for hepatitis C virus infection

The aim of the present study was to study the pathological prognostic factor of initial hepatocellular carcinoma (HCC) after archiving sustained virologic response (SVR) for hepatitis C virus (HCV) infection. A single-center retrospective analysis was performed for patients who underwent hepatectomy between 2003 and 2017. We studied clinico-pathological findings of resected liver tissues in 35 patients with HCC after SVR treated by interferon (IFN group) and 13 patients with HCC after SVR treated by direct acting antivirals (DAA group). We also performed immunohistochemical staining using antibodies against programmed death-ligand 1 (PD-L1), cytokeratin 19, epithelial cell adhesion molecule (EpCAM) and regulator of G-protein signaling 5 (RGS5). PD-L1 positive HCC was observed in 6 cases of the IFN group and 4 cases of the DAA group. In the IFN group, in univariate analysis of recurrence free survival after surgery (RFS), the PD-L1 expression had a statistically significant impact (HR=6.01; P=0.02). In the multivariate analysis of RFS, PD-L1 expression significantly remained (HR=5.01; P=0.03). For both RFS and overall survival, Kaplan-Meier curves confirmed that patients with PD-L1 expression showed significantly worse prognosis (log-rank test P<0.01). Nuclear grade, RGS5 expression, and EpCAM expression were significantly higher in the PD-L1-positive HCC group compared with the PD-L1-negative HCC group (P<0.05). Therefore, PD-L1 expression may be an independent prognostic factor of surgically resected HCC after achieving SVR.

Expression and role of regulator of G-protein signaling 5 in squamous cell carcinoma of the tongue

Regulator of G-protein signaling (RGS) 5 acts as a GTPase-activating protein to negatively regulate G-protein signaling. RGS5 is reportedly related to the invasion and metastasis of cancers, such as nonsmall lung cancer and hepatocellular carcinoma. We examined RGS5 expression and its relationship with invasion in squamous cell carcinoma (SCC) of the tongue. For immunohistochemical analysis of RGS5, we used SCC tissues of the tongue obtained from 43 patients. We examined the relationship between RGS5 expression in the deepest point of invasion and clinicopathological features. Because the invasion and metastasis of cancers are related to epithelial-mesenchymal transition (EMT), we carried out staining for N-cadherin, vimentin, and E-cadherin to examine the relationship between EMT and RGS5. RGS5 expression in the deepest point of invasion in SCC of the tongue was observed in 32 cases (75%). Immunohistochemical analysis revealed a significant correlation between RGS5 expression in the aggressive invasion pattern, invasion depth, and lymphovascular invasion. Kaplan-Meier analysis revealed that high RGS5 expression was associated with postoperative early lymph node metastasis. Further, a significant positive correlation was observed between RGS5 and N-cadherin (P = 0.0003) and vimentin (P < 0.0001). In contrast, E-cadherin and RGS5 or vimentin were significantly negatively correlated (P < 0.0001-0.005). The findings indicate that RGS5 expression is related to tumor invasion and EMT in SCC of the tongue and that RGS5 may predict postoperative early lymph node metastasis. Therefore, RGS5 may be a useful prognostic biomarker of the surgically resected SCC and a potential target of molecular therapy for treating SCC of the tongue.

High sulfite oxidase expression could predict postoperative biochemical recurrence in patients with prostate cancer

Sulfite oxidase (SUOX) is a metalloenzyme that plays a role in ATP synthesis via oxidative phosphorylation in mitochondria and has been reported to also be involved in the invasion and differentiation capacities of tumor cells. Here, we performed a clinicopathological investigation of SUOX expression in prostate cancer and discussed the usefulness of SUOX expression as a predictor of biochemical recurrence following surgical treatment in prostate cancer. This study was conducted using Tissue Micro Array specimens obtained from 97 patients who underwent radical prostatectomy at our hospital between 2007 and 2011. SUOX staining was used to evaluate cytoplasmic SUOX expression. In the high-expression group, the early biochemical recurrence was significantly more frequent than in the low-expression group (p = 0.0008). In multivariate analysis, high SUOX expression was found to serve as an independent prognostic factor of biochemical recurrence (hazard ratio = 2.33, 95% confidence interval = 1.32-4.15, p = 0.0037). In addition, Ki-67-labeling indices were significantly higher in the high-expression group than in the low-expression group (p = 0.0058). Therefore, SUOX expression may be a powerful prognostic biomarker for decision-making in postoperative follow-up after total prostatectomy and with regard to the need for relief treatment.

Abstract 5184: Expression and role of regulator of G-protein signing 5 in squamous cell carcinoma of the tongue

Objective: Regulator of G-protein signing (RGS) 5 is a member of the RGS family and acts as GTPase-activating proteins for heterotorimeric G protein αsubunits, negatively regulating G-protein signaling. RGS5 was reportedly expressed in the heart, lung, skeletal muscle and small intestine and relates with tumor angiogenesis and gestational hypertension. It was reported that RGS5 was related with the invasion and metastasis of cancers, such as non-small lung cancer and hepatocellular carcinoma. In the present study, we examined RGS5 expression and its relation with invasion in squamous cell carcinoma (SCC) of the tongue. Materials and Methods: For immunohistochemical analysis for RGS5, we used SCC tissues of the tongue obtained from 43 patients who underwent resection at Kurume University Hospital from 2011 to 2015. The staining intensity was graded as 0, negative; 1, weak; 2, moderate; 3, strong. The staining intensity in the normal epithelium was used as an internal control. We examined relationship between RGS5 expression in invasive portions and clinicopathological features (e.g., lymph node metastasis, depth of tumor, and mode of invasion, and so forth). Mode of invasion was classified into 3 levels, i.e., IFNa (expansive), IFNc (invasive), IFNb (between INFa and INFc). Depth of tumor was measured and classified into 2 levels: &lt; 5 mm and ≥ 5mm. Comparison and estimation of cumulative survival rates were performed using the Kaplan-Meier curves and log rank test. Result: Non-cancerous squamous cells expressed RGS5 solely in nucleus. SCC cells in superficial portion of tumor nodules often expressed weak nuclear RGS5 expression. In invasive portions of the tumor nodules, SCC cells expressed significantly lower nuclear and higher cytoplasmic RGS5 expression. A significant correlation was found between the expression score of RGS5 at invasive portions and mode of invasion (P=0.009). When the 43 cases were subdivided into two groups, i.e., expression group (score 1-3) and non-expression group (score 0), significant differences were observed in mode of invasion (P=0.0042), lymph node metastasis (p=0.0314), depth of tumor (p=0.0239) between the two groups. The log-rank test revealed that postoperative early lymph node metastasis was significantly higher in the expression group (p= 0.0415). Conclusion: This study suggests that RGS5 expression is related with tumor invasion in SCC of the tongue and that RGS5 can be a predictor of postoperative early lymph node metastasis.

Citation Format: Yushi Abe, Hirohisa Yano, Jun Akiba, Reiichirou kondou, Sachiko Ogasawara, Ken Nakamura, Zingo Kusukawa. Expression and role of regulator of G-protein signing 5 in squamous cell carcinoma of the tongue [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5184.

SUOX is negatively associated with multistep carcinogenesis and proliferation in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is the most common malignant tumor in the head and neck region. The aim of this study was to identify the key molecules and to elucidate the molecular mechanisms of OSCC carcinogenesis through a microarray analysis of RNA extracted from normal epithelium, dysplasia, and squamous cell carcinoma components. Out of molecules that showed changes in gene expression in the microarray analysis, we focused on Sulfite oxidase (SUOX), which correlated significantly with carcinogenic process and exhibited a stepwise decrease in expression. The expression of SUOX was evaluated in detail at the protein level using samples from 58 patients with cancer of the tongue, and correlating clinicopathological factors were also comprehensively examined. SUOX expression declined significantly from normal epithelium to dysplasia to squamous cell carcinoma components in line with carcinogenic process. With regard to squamous cell carcinoma, SUOX expression was significantly lower when T classification was high. Our findings indicated that SUOX is negatively associated with the progression and proliferation of tongue cancer, and suggest that SUOX may be a key molecule in tongue tumors.

Regulator of G-protein signaling 5 enhances portal vein invasion in hepatocellular carcinoma

Portal vein invasion (PVI) is a major prognostic factor in hepatocellular carcinoma (HCC). The aim of the present study was to identify molecules that regulate PVI. Sections of cancerous tissue, paired noncancerous tissue and the PVI area were collected from 3 frozen HCC sections, using laser microdissection. The present study focused on 3 upregulated molecules, integrin β3 (ITGB3), secreted phosphoprotein 1 (SPP1) and regulator of G-protein signaling 5 (RGS5), and 2 molecules that were downregulated in PVI tissue compared with cancer tissue, metallothionein 1G (MT1G) and metallothionein 1H (MT1H), as determined by cDNA microarray analysis. Reverse transcription-quantitative polymerase chain reaction analysis of 32 HCC cases revealed that RGS5 mRNA levels were significantly increased and MT1 G and MT1H mRNA levels were significantly decreased in cancerous tissue compared with noncancerous tissue. However, there was no significant difference in ITGB3 and SPP1 expression. There were no significant differences between the expression of these molecules and any clinicopathologic factors, including PVI. Immunohistochemical staining for RGS5 in 60 HCC cases demonstrated that RGS5 protein levels were higher in cancerous tissue compared with paired noncancerous tissue in 63.3% of HCC cases. Furthermore, high expression of RGS5 in cancerous tissue was significantly associated with PVI and tended to be associated with intrahepatic metastasis. Confluent multinodular type was significantly more frequent in cases with high expression of RGS5 in the cancerous tissue. Therefore, RGS5 may be a useful prognostic biomarker as well as a potential target of molecular therapy to treat HCC.

Effect of sorafenib on des-γ-carboxyprothrombin secretion by a human hepatocellular carcinoma cell line

Patients with hepatocellular carcinoma (HCC) who respond to sorafenib have been reported to exhibit an increase in the level of des-γ-carboxyprothrombin (DCP) in the blood, subsequent to the initiation of sorafenib treatment. In the present study, the levels of secretion of DCP and DCP with more γ-carboxyglutamic residues (NX-DCP) and the effects of hypoxic conditions were examined in 13 liver cancer cell lines, and the presence of vitamin K and sorafenib, in the KYN-2 cell line, which resulted in confirmed DCP and NX-DCP secretion. DCP, NX-DCP and prothrombin secretion were confirmed in 2/13 cell lines, KYN-2 and KIM-1. The level of secretions increased under hypoxic conditions. The addition of vitamin K suppressed cell proliferation, and DCP expression decreased to below detectable levels, however the level of prothrombin expression increased. Sorafenib treatment increased the level of apoptosis and suppressed cell proliferation, and decreased DCP and NX-DCP. In contrast, levels of prothrombin and vascular endothelial growth factor (VEGF) expression exhibited a slight increase. When the same experiment was conducted under hypoxic conditions, DCP secretion significantly decreased in the presence of sorafenib. The level of DCP secretion increased by several fold in the sorafenib-treated and non-treated cells compared with the normoxic conditions. Prothrombin and VEGF values with normoxic conditions remained almost similar with hypoxic conditions. Under hypoxic conditions, NX-DCP significantly decreased below the control values for the first 48 h subsequent to sorafenib treatment, but significantly increased at 72 h. In vivo experiments demonstrated that sorafenib inhibited angiogenesis and tumor proliferation, but the levels of DCP and NX-DCP did not differ significantly from the controls. These findings indicate that the suppression of neovascularization by sorafenib promotes blood vessel ischemia, producing hypoxic conditions whereby vitamin K uptake and utilization efficiency is reduced.

Antiproliferative effect of ME3738, a derivative of soyasapogenol, on hepatocellular carcinoma cell lines in vitro and in vivo

Soyasapogenol, an aglycon of soyasaponin, ameliorates liver injury induced by concanavalin A in mice. A derivative of soyasapogenol, 22β-methoxyolean-12-ene-3β, 24(4β)-diol (ME3738), was reported to induce the gene expression of interferon (IFN)-β in hepatitis C virus replicon cells. The effect of ME3738 on hepatocellular carcinoma (HCC) cell lines was investigated in the present study. A total of 11 HCC cell lines were cultured in medium containing 0-10 µM ME3738, and after 24, 48, or 72 h of culture, morphological observation and MTT cell growth assays were performed. Furthermore, the effects of ME3738 with or without PEG-IFN-α-2b on cell lines were investigated. Induction of apoptosis was examined on cells treated with 1 µM of ME3738 using an Annexin V assay. The effect of ME3738 (0.63 and 2.5 µM) on cell cycle progression was analyzed on two cell lines. The mice with subcutaneous tumors were divided into four groups: i) Control; ii) ME3738 alone; iii) PEG-IFN-α-2b alone and iv) ME3738+PEG-IFN-α-2b (combination). ME3738 was mixed with food (1.5 mg/g) and was taken orally for 15 days. PEG-IFN-α-2b (1,920 IU/mouse) was subcutaneously injected twice a week for two consecutive weeks. On day 15, the mice were sacrificed and the tumors were resected. A dose-dependent anti-proliferative effect was observed to various degrees in all the HCC cell lines in vitro. This inhibitory effect reached its maximal level 24 h after the treatment and the 50% inhibitory dose was between 0.8 and 2.4 µM. The combination treatment did not show a synergistic effect. Induction of apoptosis was not observed. Cell cycle arrest at S-phase was observed in two of the examined cell lines. On day 15, the tumor volume of mice receiving ME3738, PEG-IFN-α-2b, and ME3738+PEG-IFN-α-2b was 69, 30, and 33%, respectively, of the control tumor volume. ME3738 induced antiproliferative effects on the HCC cells in vitro and in vivo. The data suggested potential clinical application of ME3738.

Muscle RAS oncogene homolog (MRAS) recurrent mutation in Borrmann type IV gastric cancer

The prognosis of patients with Borrmann type IV gastric cancer (Type IV) is extremely poor. Thus, there is an urgent need to elucidate the molecular mechanisms underlying the oncogenesis of Type IV and to identify new therapeutic targets. Although previous studies using whole-exome and whole-genome sequencing have elucidated genomic alterations in gastric cancer, none has focused on comprehensive genetic analysis of Type IV. To discover cancer-relevant genes in Type IV, we performed whole-exome sequencing and genome-wide copy number analysis on 13 patients with Type IV. Exome sequencing identified 178 somatic mutations in protein-coding sequences or at splice sites. Among the mutations, we found a mutation in muscle RAS oncogene homolog (MRAS), which is predicted to cause molecular dysfunction. MRAS belongs to the Ras subgroup of small G proteins, which includes the prototypic RAS oncogenes. We analyzed an additional 46 Type IV samples to investigate the frequency of MRAS mutation. There were eight nonsynonymous mutations (mutation frequency, 17%), showing that MRAS is recurrently mutated in Type IV. Copy number analysis identified six focal amplifications and one homozygous deletion, including insulin-like growth factor 1 receptor (IGF1R) amplification. The samples with IGF1R amplification had remarkably higher IGF1R mRNA and protein expression levels compared with the other samples. This is the first report of MRAS recurrent mutation in human tumor samples. Our results suggest that MRAS mutation and IGF1R amplification could drive tumorigenesis of Type IV and could be new therapeutic targets.

Clinicopathological features of neoplasms with neuroendocrine differentiation occurring in the liver

BACKGROUND/AIMS

We investigated the clinicopathological features of hepatic neuroendocrine tumours (NET) and neuroendocrine carcinoma (NEC), which remain largely unknown.

MATERIAL AND METHODS

We examined 1235 tumours from 1048 patients who had undergone curative hepatectomy for liver neoplasms at Kurume University Hospital. Pathological diagnoses were based on the 2010 WHO Classification of Tumours of the Digestive System. We performed immunostaining for hepatocyte markers (eg, hepatocyte paraffin (HepPar)-1), neuroendocrine markers (eg, chromogranin A (CGA)) and the proliferation marker (Ki-67).

RESULTS

There were four cases of NET G2 (0.38%) and five of hepatic malignant tumours with an NEC component (HNEC) (0.48%). HNEC cases were classified into three types, that is, transitional, intermediate and separate types, according to their histological and immunohistochemical features. In the former two types, the NEC component intermingled with the moderately to poorly differentiated hepatocellular carcinoma (HCC) component or intermediate component consisting of tumour cells showing the colocalisation of CGA and HepPar-1. In the separate type, the NEC and poorly differentiated HCC components were present separately, whereas the sarcomatous HCC component was detected in the vicinity of the NEC component. Ki-67 labelling indices of the NET G2, HCC and NEC components of HNEC were 6.8%, 14.9% and 58.9%, respectively.

CONCLUSIONS

Primary hepatic NET and NEC are very rare tumours. The NEC component in HNEC showed high proliferative activity and influenced patient prognoses.

ARHGEF15 overexpression worsens the prognosis in patients with pancreatic ductal adenocarcinoma through enhancing the motility and proliferative activity of the cancer cells

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive neoplastic diseases, associated with a remarkably poor prognosis. However, the molecular mechanisms underlying the development of PDAC remain elusive. The aim of this study was to identify genes whose expressions are correlated with a poor prognosis in PDAC patients, and to unravel the mechanisms underlying the involvement of these genes in the development of the cancer.

METHODS

Global gene expression profiling was conducted in 39 specimens obtained from Japanese patients with PDAC to identify genes whose expressions were correlated with a shorter overall survival. The effect of gene silencing or overexpression of ARHGEF15 in pancreatic cancer cell lines was examined by introducing siRNAs of ARHGEF15 or the ARHGEF15 expression vector. After assessing the effect of ARHGEF15 deregulation on the Rho-family proteins by pull-down assay, wound healing, transwell and cell viability assays were carried out to investigate the cellular phenotypes caused by the perturbation.

RESULTS

The global mRNA expression profiling revealed that overexpression of ARHGEF15, a Rho-specific GEF, was significantly associated with a poor prognosis in patients with PDAC. We also found that the depletion of ARHGEF15 by RNA interference in pancreatic cancer cell lines downregulated the activities of molecules of the Rho signaling pathway, including RhoA, Cdc42 and Rac1. Then, we also showed that ARHGEF15 silencing significantly reduced the motility and viability of the cells, while its overexpression resulted in the development of the opposite phenotype in multiple pancreatic cancer cell lines.

CONCLUSION

These data suggest that upregulation of ARHGEF15 contributes to the development of aggressive PDAC by increasing the growth and motility of the pancreatic cancer cells, thereby worsening the prognosis of these patients. Therefore, ARHGEF15 could serve as a novel therapeutic target in patients with PDAC.

The expression of arginase-1, keratin (K) 8 and K18 in combined hepatocellular-cholangiocarcinoma, subtypes with stem-cell features, intermediate-cell type

AIMS

The WHO classification describes that combined hepatocellular-cholangiocarcinoma, subtypes with stem-cell features, intermediate-cell subtype (CHC-INT) is composed of tumour cells with features intermediate between hepatocytes and cholangiocytes. However, we previously reported that CHC-INT showed a high positive rate of biliary markers, but the expression of hepatocyte paraffin (HepPar)-1 was low. In this study, we examined the expression of other hepatocyte markers, such as arginase-1 (Arg-1), keratin (K) 8 and K18 in CHC-INT in order to examine the utility of pathological diagnosis in CHC-INT.

METHODS

We performed immunohistochemistry (IHC) of Arg-1, K8 and K18 using 32 previously diagnosed as CHC-INT. Immunoreactivity was evaluated with grading from 0 to 4 according to the distribution area of positive cells. The obtained findings of Arg-1, K8 and K18 were compared with those of K7, K19 and HepPar-1.

RESULTS

Out of the 32 cases, 22 (68.8%) cases were positive for Arg-1. Twenty-five (78.1%) were positive for K8. The IHC scores of Arg-1 and K8 were significantly higher than those of HepPar-1, but significantly lower than those of K7 and K19. The K18 expression was widely observed in all cases (100%). The IHC score of Arg-1 and K8 in CHC-INT was intermediate between hepatocellular carcinoma and cholangiocarcinoma.

CONCLUSIONS

Arg-1 and K8 were good markers to identify intermediate cells between hepatocytes and cholangiocytes. These can be useful markers for pathological diagnosis of CHC-INT, which usually has wide histological diversities, in combination with other hepatocytic and/or cholangiocytic markers.

Growth inhibitory effect of an injectable hyaluronic acid-tyramine hydrogels incorporating human natural interferon-α and sorafenib on renal cell carcinoma cells

Immunotherapy including interferon-alpha (IFN-α) is one of the treatment options for metastatic renal cell carcinoma (mRCC) patients. Despite clinical benefits for the selected patients, IFN-α therapy has some problems, such as poor tolerability and dose-limiting adverse effects. In addition, the frequent injections reduce a patient's quality of life and compliance. Recently, an injectable and biodegradable hydrogel system to prolong drug release is reported. In this study, we investigated the anticancer effect of IFN-α (Sumiferon®)-incorporated hyaluronic acid-tyramine (HA-Tyr) hydrogels in human RCC-xenografted in nude mice. We also evaluated the synergistic efficacy of IFN-α-incorporated HA-Tyr hydrogels+sorafenib in this model. IFN-α-incorporated HA-Tyr hydrogels+sorafenib most effectively inhibited tumor growth on human RCC cells xenografted in nude mice. In addition, IFN-α-incorporated HA-Tyr hydrogels+sorafenib inhibited the proliferation of tumor in nude mice by inducing apoptosis and the suppression of angiogenesis. Our results suggest a possibility that HA-Tyr hydrogel drug delivery system prolongs the biological half-life of natural human IFN-α and enhances its anticancer effects on human RCC cells.

STATEMENT OF SIGNIFICANCE

The scope of this study is to provide an alternative approach to improve the anticancer efficacy in renal cell carcinoma (RCC) treatment by using hyaluronic acid-tyramine (HA-Tyr) hydrogel drug delivery system. We investigated the anticancer effect of natural interferon-α (IFN-α)-incorporated HA-Tyr hydrogels in RCC cells. We also evaluated the synergistic efficacy of natural human IFN-α-incorporated HA-Tyr hydrogels+sorafenib. We demonstrated that HA-Tyr hydrogel system is able to release natural human IFN-α in sustained manner and enhances its anticancer effects on human RCC cells. In addition, we suggested that IFN-α-incorporated HA-Tyr hydrogels+sorafenib exhibited most effectively anticancer effects. Hence, we believe that this approach could be applied to treatment with RCC in the future.

CD44v3+/CD24- cells possess cancer stem cell-like properties in human oral squamous cell carcinoma

Cancer stem cells (CSCs) or cancer stem cell-like cells (CSC-LCs) are a minority population of cells that relate to tumor progression, metastasis and drug resistance. To identify CSC-LCs in oral squamous cell carcinoma (OSCC), we used two OSCC cell lines, SAS and OSC20, and cell surface markers, CD44v3 and CD24. In addition, we examined CD44v3 and CD24 expression immunohistochemically and evaluated the relationship between the expression and clinicopathological parameters in 50 OSCC tissues. In SAS and OSC20, CD44v3+/CD24- cells showed a higher sphere forming ability than the other fractions, i.e., CD44v3+/CD24+, CD44v3-/CD24- and CD44v3-/CD24+ cells. The proportion of CD44v3+/CD24- cells in SAS and OSC20 was 10.7 and 24.1%, respectively. Regarding SAS, CD44v3+/CD24- cells also showed a higher drug resistance for CDDP, 5-FU and cetuximab and expressed higher mRNA levels of CSC property-related genes than the other cell fractions. The tumorigenicity of CD44v3+/CD24- cells was not significantly different from the other fractions in SAS. An immunohistochemical study revealed a significant correlation between CD44v3 expression in the invasive portion and lymph node metastasis. Kaplan Meier analysis revealed cases with CD44v3 expression in the invasive portion tended to show poor overall survival (OS) compared with those without CD44v3, and there was a significant difference in OS between CD44v3+/CD24- and CD44v3-/CD24- immunophenotypes in the invasive portion. In conclusion, the results suggest that the CD44v3+/CD24- cell population displays CSC-LC properties in a human OSCC cell line. Additionally, we present evidence that CD44v3 immunoexpression and CD44v3+/CD24- immunophenotypes could give prognostic information associated with unfavorable clinical outcomes.

Abstract 1393: CD44v3-positive (CD44v3+) and CD24-negative (CD24−) cells possess cancer stem cell (CSC)-like properties in a human oral squamous cell carcinoma cell line

Background:

CSCs are defined as minor cell population which have higher tumor-initiating ability, self-renewal ability and multilineage potential. Although CSCs in oral squamous cell carcinoma (OSCC) were identified by several surface antigen (e.g., CD44, CD133) or ALDEFLOUR assay, it is still elusive which are universal markers for CSC in OSCC. The aim of this study is to clarify potential CSC markers for a OSCC cell line using a combination of cell surface markers, CD44v3 and CD24.

Materials and Methods: A OSCC cell line, SAS, was used in the experiment. CD44v3+/CD24− cell fraction was sorted from SAS cells with a FACSAria II and compared with the other three fractions (CD44v3+/CD24+, CD44v3− /CD24−, CD44v3−/CD24+ cell fraction) in cell proliferation, drug resistance and sphere forming ability. mRNA expression levels of various genes, such as stemness genes, anti-apoptosis genes and hypoxia-related genes, were compared among the fractions using quantitative real-time reverse transcriptase-polymerase chain reaction.

Results:

The proportion of CD44v3+/CD24−, CD44v3+/CD24+, CD44v3−/CD24−, CD44v3−/CD24+ cells was 34.9%, 39.8%, 14.2% and 11.0%, respectively. CD44v3+/CD24− cells showed a higher sphere forming ability, and drug resistance for CDDP, 5-FU and Cetuximab and expressed higher mRNA levels of CSC property-related genes (ABCG2, Oct-4, Nanog) and a hypoxia-related gene (HIF-1α) than the other cell fractions. There were no significant differences in cell proliferation among the fractions.

Conclusion:

The results suggest that CD44v3+/CD24− cell fractions in SAS possess CSC-like properties. The investigation of tumorigenic capacity in NOD/SCID mice is now under way.

Citation Format: Keita Todoroki, Sachiko Ogasawara, Jun Akiba, Masamichi Nakayama, Yoshiki Naito, Jingo Kusukawa, Hirohisa Yano. CD44v3-positive (CD44v3+) and CD24-negative (CD24−) cells possess cancer stem cell (CSC)-like properties in a human oral squamous cell carcinoma cell line. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1393. doi:10.1158/1538-7445.AM2015-1393

Abstract 2975: Comprehensive analysis of genetic alterations and DNA copy number in Borrmann type IV gastric cancer

The prognosis of patients with Borrmann type IV gastric cancer (Type IV) is extremely poor. Thus, there is an urgent need to elucidate the molecular mechanisms underlying the oncogenesis of Type IV and to identify new therapeutic targets. Although previous studies using whole-exome and whole-genome sequencing have elucidated genomic alternations in gastric cancer, no reports have focused on the comprehensive genetic analysis in Type IV. To find cancer relevant genes in Type IV, we performed whole exome sequencing and genome-wide copy number analysis on 14 patients of Type IV. The exome sequencing identified a total of 182 somatic mutations which cause amino-acid substitutions or splice-site alterations. Previously reported mutations in gastric cancer were detected, such as ARID1A, CDH1, TP53 and RHOA. Moreover, our study has found novel mutations that have not been reported in gastric cancer and other tumor types. Among the newly identified genetic alterations, a mutation in muscle RAS oncogene homolog (MRAS) was predicted to cause molecular dysfunction. MRAS belongs to the Ras subgroup of small G proteins, including the prototypic RAS oncogene, KRAS, HRAS, and NRAS. The MRAS mutation discovered by whole-exome sequencing was validated by mutation-specific PCR. To investigate the frequency of mutation in MRAS, we performed Sanger sequencing of additional 46 Type IV samples. A total of 9 non-synonymous mutations were discovered with a mutation frequency of 17%, showing that MRAS is recurrently mutated in Type IV. The genome-wide copy number analysis also showed that copy number was aberrant in 41 genes, including Insulin-like growth factor 1 receptor (IGF1R). The samples with IGF1R amplification showed remarkably higher expression levels of mRNA and protein compared with other samples. In conclusion, this is the first research to discover mutation in MRAS among human tumor samples, although introduction of artificially mutated MRAS is known to have oncogenic activity. In addition, these results suggested that MRAS mutation and IGF1R amplification could drive tumorigenesis of Type IV and could be a new therapeutic target for Type IV.

Citation Format: Makiko Yasumoto, Sachiko Ogasawara, Jun Akiba, Hironori Kusano, Akiko Sumi, Taro Isobe, Junya Kizaki, Yoshito Akagi, Takuji Torimura, Etsuko Sakamoto, Hiraku Itadani, Tsutomu Kobayashi, Shinji Mizuarai, Shinji Oie, Hirohisa Yano. Comprehensive analysis of genetic alterations and DNA copy number in Borrmann type IV gastric cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2975. doi:10.1158/1538-7445.AM2015-2975

Abstract 514: ARHGEF15 is associated with a poor prognosis in patients with pancreatic ductal adenocarcinoma through a mechanism involving the enhancement of cellular motility and proliferation

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive cancers and is associated with an extremely poor prognosis, since it is difficult to diagnose pancreatic cancer at an early stage despite its remarkably aggressive features. However, the molecular mechanism underlying the development of aggressive PDAC remains elusive. Rho guanine nucleotide exchange factors (ARHGEFs) are known to activate the RhoA signaling pathway in several types of tumor, although its association with the outcome of PDAC has not been reported. Here, we report that a higher expression of ARHGEF15 is significantly associated with a poor prognosis among PDAC patients, and an increase in ARHGEF15 expression plays pivotal roles in the enhancement of cellular motility and the proliferation of PDAC cells. Firstly, we found that a higher level of ARHGEF15 was significantly correlated with a poor prognosis among 39 Japanese patients with PDAC using global gene expression profiling with an Affymetrix microarray. We then showed that RNA interference-mediated gene silencing of ARHGEF15 inactivated the RhoA signaling pathway when examined using a RhoA pull-down assay. Next, the assessment of cellular migration using both a transwell chamber assay and a wound healing assay showed that ARHGEF15 silencing down-regulated cellular migration and invasive ability in pancreatic cancer cell lines with high levels of endogenous ARHGEF15 expression. Since the RhoA signaling pathway is involved in cell proliferation, we also examined the effect of ARHGEF15-silencing on cell viability and observed that ARHGEF15-knockdown markedly retarded cellular growth in the pancreatic cell lines. In parallel with the gene-silencing studies, the effect of ARHGEF15-overexpression was also investigated in pancreatic cell lines with low levels of endogenous ARHGEF15 expression. We observed opposite phenotypes to those observed in the gene-silencing studies: increased cellular motility and viability, compared with the controls, was observed as a result of overexpression. This is the first study to suggest that a higher expression of ARHGEF15 was correlated with a poor prognosis among patients with pancreatic cancer. In addition, these data suggested that the overexpression of ARHGEF15 contributed to a poor prognosis among PDAC patients by enhancing tumor motility and proliferation, suggesting that ARHGEF15 could be a prognostic biomarker as well as a novel therapeutic target for PDAC.

Citation Format: Hiroto Fukushima, Makiko Yasumoto, Sachiko Ogasawara, Jun Akiba, Yuhei Kitasato, Yoshiki Naito, Masamichi Nakayama, Yoshinobu Okabe, Masafumi Yasunaga, Hiroyuki Horiuchi, Etsuko Sakamoto, Hiraku Itadani, Shinji Mizuarai, Shinji Oie, Hirohisa Yano. ARHGEF15 is associated with a poor prognosis in patients with pancreatic ductal adenocarcinoma through a mechanism involving the enhancement of cellular motility and proliferation. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 514. doi:10.1158/1538-7445.AM2015-514

Des-γ-carboxyprothrombin (DCP) and NX-DCP expressions and their relationship with clinicopathological features in hepatocellular carcinoma

Aim

Des-γ-carboxyprothrombin (DCP) has been used as a tumor marker for hepatocellular carcinoma (HCC). Recently the DCP/NX-DCP ratio, calculated by dividing DCP by NX-DCP, has been reported useful in detecting HCC. The purpose of this study is to clarify the significance of DCP and NX-DCP expression in HCC tissues.

Methods

HCC and non-HCC tissue samples were obtained from 157 patients and were immunohistochemically examined for DCP and NX-DCP expression using anti-DCP antibody and anti-NX-DCP antibody. DCP and NX-DCP expression scores were calculated by multiplying staining intensity grade by percentage of stained area. Serum DCP and NX-DCP levels were determined in 89 patients. We evaluated the relationship between tumor expression, serum level, and pathomorphological findings.

Results

Intrahepatic metastasis (im) was significantly more frequent in cases with high DCP expression than in cases with low DCP expression. High NX-DCP expression was associated with significantly lower histological grade, and less frequent im or portal vein invasion (vp) than low NX-DCP expression. Serum DCP was correlated with DCP expression, but serum NX-DCP was not correlated with NX-DCP expression. DCP-positive (≥40 mAU/L), NX-DCP-positive (≥90 mAU/L), and DCP/NX-DCP ratio-positive (≥1.5) cases were associated with significantly larger tumor size and more frequent vp than negative cases. DCP was rarely expressed, but NX-DCP was frequently expressed in non-cancerous liver tissues. Patients with NX-DCP expression-negative tumors showed a lower survival rate than those with NX-DCP expression-positive tumors (p = 0.04), whereas the survival in serum NX-DCP-positive cases was lower than that of serum negative cases (p = 0.02).

Conclusions

DCP and NX-DCP were produced in HCC tissues, but differed in expression level and biological properties. DCP expression, serum DCP or NX-DCP level, and DCP/NX-DCP ratio were closely related to malignant properties of HCC.

Epithelial cell adhesion molecule-positive human hepatic neoplastic cells: development of combined hepatocellular-cholangiocarcinoma in mice

BACKGROUND AND AIM

Human combined hepatocellular-cholangiocarcinoma (CHC) expresses several hepatic stem/progenitor cell (HSPC) markers, suggesting this neoplasm originates from HSPCs. We examined the significance of HSPC marker in CHC using a human CHC cell line.

METHODS

We used a human CHC cell line (KMCH-1) previously established in our laboratory. The original tumor was classified as CHC, showing areas of typical hepatocellular carcinoma (HCC) and cholangiocarcinoma (ChC). We examined the expression of HSPC markers and hepatocyte markers in KMCH-1 by flow cytometry (FCM) and quantitative real-time polymerase chain reaction. EpCAM(+) and EpCAM(-) KMCH-1 cells were isolated. Subsequently, their morphological features, HSPC marker expression, and biological characteristics were examined in vitro and in vivo.

RESULTS

FCM showed expression of EpCAM, K7, K19, and ABCG2 in KMCH-1, with various degrees. EpCAM(+) cells expressed K19 mRNA, but did not express α-fetoprotein (AFP). In contrast, EpCAM(-) cells expressed AFP mRNA, but did not express K19. EpCAM(+) cells produced both EpCAM(+) and EpCAM(-) cells, but EpCAM(-) cells produced only EpCAM(-) cells in vitro. EpCAM(+) cells showed higher tumorigenicity and formed larger tumors than EpCAM(-) cells. Inoculation of EpCAM(+) and EpCAM(-) cells produced both ChC and HCC-like component and HCC-like component only, respectively.

CONCLUSION

It is speculated that some CHCs may originate from EpCAM(+) neoplastic cells, and that these cells may affect malignant behavior and progression in such CHCs.

Development of fast steering mirror control system for plasma heating and diagnostics

A control system for a fast steering mirror has been newly developed for the electron cyclotron heating (ECH) launchers in the large helical device. This system enables two-dimensional scan during a plasma discharge and provides a simple feedback control function. A board mounted with a field programmable gate array chip has been designed to realize feedback control of the ECH beam position to maintain higher electron temperature by ECH. The heating position is determined by a plasma diagnostic signal related to the electron temperature such as electron cyclotron emission and Thomson scattering.

Abstract 880: Des-g-carboxyprothrombin (DCP) and NX-DCP expressions and their relationship with clinicopathological features in hepatocellular carcinoma

Aim: Des-g-carboxyprothrombin (DCP) is an abnormal prothrombin and has been used as a tumor marker of hepatocellular carcinoma (HCC). DCP has several variants based on the number of glutamic acid (Glu) residues and their positions in the γ-carboxyglutamic (Gla) domain. DCP expression in HCC tissues has been identified using MU-3 antibody which reacts strongly to DCP containing less Gla residues. Serum DCP also increases in patients with vitamin K deficiency, in which DCP containing more Gla residues (NX-DCP) elevates and can be detected using P-11 or P-16 antibody. Recently, NX-DCP-R, calculated by dividing DCP by NX-DCP, is reportedly useful for the diagnosis of HCC in such patients as taking warfarin. In this study is, we evaluated tissue DCP and NX-DCP expression in HCC.

Materials and Methods: Tissue samples of HCC and non-HCC were obtained from 157 patients and were immunohistochemically examined for tissue DCP and NX-DCP expression using MU-3 antibody and P-16 antibody, respectively. Immunostain of HCC was evaluated according to staining intensity and stained area (0-1) within the tumor. The staining intensity was graded into 4 levels (0, negative; 1, weakly; 2, moderately; 3, strongly). The expression score was calculated by multiplying staining intensity grade by stained area. Additionally, serum DCP level and NX-DCP level were determined in 89 patients. We evaluated the relationship among the tissue expression, serum level, and pathomorphological findings. Additionally, immunostain of noncancerous tissues was evaluated according to the stained area.

Results: DCP and NX-DCP expressions were found in 69/157 (44%) cases and 35/157 (22%) cases, respectively, in HCC tissue. The expression score of DCP [0.54 ± 0.82 (mean ± SD)] was higher than that of NX-DCP [0.15 ± 0.39]. The DCP expression score was significantly higher in the cases of non-simple nodular type, moderately-poorly differentiated type, and in the cases without capsule formation, and in those with intrahepatic metastasis (im) or portal vein invasion (vp). On the other hand, NX-DCP expression score was significantly higher in the cases of well-differentiated type, and in the cases without im. There was the correlation between serum DCP level and DCP expression score, but there was no correlation between serum NX-DCP level and NX-DCP expression score. DCP-positive (≥40 AU/L) or NX-DCP-R-positive (≥ 1.5) cases were significantly larger in tumor size, higher in histological grade and more frequent in vp than negative cases. In noncancerous liver tissues, DCP was rarely expressed, but NX-DCP was much more frequently expressed.

Conclusion: An increase in tissue DCP expression, serum DCP level, and NX-DCP-R was closely related with malignant properties of HCC. In contrast, NX-DCP is less frequently expressed and showed different biological properties from DCP in HCC.

Citation Format: Akiko Sumi, Jun Akiba, Sachiko Ogasawara, Masamichi Nakayama, Yoriko Nomura, Sakiko Sanada, Osamu Nakashima, Takuji Torimura, Toshi Abe, Hirohisa Yano. Des-g-carboxyprothrombin (DCP) and NX-DCP expressions and their relationship with clinicopathological features in hepatocellular carcinoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 880. doi:10.1158/1538-7445.AM2014-880

Abstract 4464: Growth inhibitory effect of combination of sorafenib and IFNα using a new drug delivery system

Background: Immunotherapy including IFNα is one of the treatment options for metastatic renal cell carcinoma (mRCC) patients, especially Japanese mRCC patients. Recent reports showed that IFNα not only has direct antitumor and anti-angiogenic activity, but also enhances the anti-tumor and anti-angiogenic effects of sorafenib. Despite clinical benefits for the selected patients, IFNα therapy has some problems, such as poor tolerability and dose-limiting adverse effects. In addition, the frequent injections reduce a patient's quality of life and compliance. Recently, an injectable and biodegradable hydrogel system to prolong drug release is reported. The hydrogel system has demonstrated that IFNα2a-incorporated hydrogels inhibit the tumor growth more than IFNα2a solution alone. In this study, we evaluated the synergistic efficacy of IFNα-incorporated Hyaloronic acid-Tyramine (HA-Tyr) hydrogels and sorafenib in tumor regression.

Material and Methods: We used a RCC cell line, ACHN. ACHN cells (5×106 cells) were subcutaneously injected to the back of 5-week-old female BALB/c nude mice. Each group (n=8) was assigned to one of the five treatments: 1) control; 2) IFNα alone; 3) sorafenib alone; 4) IFNα + sorafenib; 5) IFNα-incorporated HA-Tyr hydrogels + sorafenib. IFNα (4,000 IU) and IFNα (4,000 IU)-incorporated HA-Tyr hydrogels were injected subcutaneously twice a week (Day 1, 4, 8 and 11), and sorafenib (200 µg/day) was given orally every day for 2 weeks. Tumor volume was monitored during the experiment. On Day 15, the mice were sacrificed and the tumors were resected and weighed. Proliferative activity and presence of apoptosis of the tumors were examined by Ki-67 immunostain and TUNEL assay.

Results: The tumor volume of mice that received IFNα, sorafenib, IFNα + sorafenib, IFNα-incorporated HA-Tyr hydrogels + sorafenib was 85, 74, 67 and 53%, respectively, of the control and the tumor weight was 94, 86, 89 and 55 %, respectively, of the control. There was a significant difference in tumor weight between IFNα-incorporated HA-Tyr hydrogels + sorafenib and IFNα + sorafenib (p&lt;0.05). Ki-67 labeling index was significantly lower in the IFNα-incorporated HA-Tyr hydrogels + sorafenib treatment group than in the other groups. In addition, apoptotic cells were significantly higher in the IFNα-incorporated HA-Tyr hydrogels + sorafenib treatment group than in the other group.

Conclusion: Our results suggest a possibility that HA-Tyr hydrogel drug delivery system prolongs the biological half-life of natural human

IFNα and enhances its anticancer effects on human RCC cells.

Citation Format: Kosuke Ueda, Jun Akiba, Sachiko Ogasawara, Keita Todoroki, Masamichi Nakayama, Akiko Sumi, Hironori Kusano, Sakiko Sanada, Shigetaka Suekane, Keming Xu, Motoichi Kurisawa, Kei Matsuoka, Hirohisa Yano. Growth inhibitory effect of combination of sorafenib and IFNα using a new drug delivery system. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4464. doi:10.1158/1538-7445.AM2014-4464