Tomoyuki Hayashi

The transcription factor SALL4 regulates stemness of EpCAM-positive hepatocellular carcinoma.

BACKGROUND & AIMS Recent evidence suggests that hepatocellular carcinoma can be classified into certain molecular subtypes with distinct prognoses based on the stem/maturational status of the tumor. We investigated the transcription program deregulated in hepatocellular carcinomas with stem cell features. METHODS Gene and protein expression profiles were obtained from 238 (analyzed by microarray), 144 (analyzed by immunohistochemistry), and 61 (analyzed by qRT-PCR) hepatocellular carcinoma cases. Activation/suppression of an identified transcription factor was used to evaluate its role in cell lines. The relationship of the transcription factor and prognosis was statistically examined. RESULTS The transcription factor SALL4, known to regulate stemness in embryonic and hematopoietic stem cells, was found to be activated in a hepatocellular carcinoma subtype with stem cell features. SALL4-positive hepatocellular carcinoma patients were associated with high values of serum alpha fetoprotein, high frequency of hepatitis B virus infection, and poor prognosis after surgery compared with SALL4-negative patients. Activation of SALL4 enhanced spheroid formation and invasion capacities, key characteristics of cancer stem cells, and up-regulated the hepatic stem cell markers KRT19, EPCAM, and CD44 in cell lines. Knockdown of SALL4 resulted in the down-regulation of these stem cell markers, together with attenuation of the invasion capacity. The SALL4 expression status was associated with histone deacetylase activity in cell lines, and the histone deacetylase inhibitor successfully suppressed proliferation of SALL4-positive hepatocellular carcinoma cells. CONCLUSIONS SALL4 is a valuable biomarker and therapeutic target for the diagnosis and treatment of hepatocellular carcinoma with stem cell features.

Defeating EpCAM+ liver cancer stem cells by targeting chromatin remodeling enzyme CHD4 in human hepatocellular carcinoma

BACKGROUND & AIMS Hepatocellular carcinoma is composed of a subset of cells with enhanced tumorigenicity and chemoresistance that are called cancer stem (or stem-like) cells. We explored the role of chromodomain-helicase-DNA-binding protein 4, which is encoded by the CHD4 gene and is known to epigenetically control gene regulation and DNA damage responses in EpCAM(+) liver cancer stem cells. METHODS Gene and protein expression profiles were determined by microarray and immunohistochemistry in 245 and 144 hepatocellular carcinoma patients, respectively. The relationship between gene/protein expression and prognosis was examined. The functional role of CHD4 was evaluated in primary hepatocellular carcinoma cells and in cell lines in vitro and in vivo. RESULTS CHD4 was abundantly expressed in EpCAM(+) hepatocellular carcinoma with expression of hepatic stem cell markers and poor prognosis in two independent cohorts. In cell lines, CHD4 knockdown increased chemosensitivity and CHD4 overexpression induced epirubicin chemoresistance. To inhibit the functions of CHD4 that are mediated through histone deacetylase and poly (ADP-ribose) polymerase, we evaluated the effect of the histone deacetylase inhibitor suberohydroxamic acid and the poly (ADP-ribose) polymerase inhibitor AG-014699. Treatment with either suberohydroxamic acid or AG-014699 reduced the number of EpCAM(+) liver cancer stem cells in vitro, and suberohydroxamic acid and AG-014699 in combination successfully inhibited tumor growth in a mouse xenograft model. CONCLUSIONS CHD4 plays a pivotal role in chemoresistance and the maintenance of stemness in liver cancer stem cells and is therefore a good target for the eradication of hepatocellular carcinoma.

Detection of pharyngeal cancer in the overall population undergoing upper GI endoscopy by using narrow-band imaging: a single-center experience, 2009–2012

BACKGROUND Nonmagnifying observation by using narrow-band imaging (NBI) is useful for detecting pharyngeal lesions. Magnifying observation by using NBI can distinguish between cancerous and noncancerous lesions and is therefore useful for the early detection of pharyngeal cancer. OBJECTIVE To evaluate the usefulness of observation of the pharynx by using NBI in the overall population undergoing upper GI endoscopy. DESIGN Retrospective study. SETTING Single tertiary referral center. PATIENTS A total of 11,050 upper GI endoscopies between January 2009 and December 2012. INTERVENTIONS Observation of the pharynx by using NBI. MAIN OUTCOME MEASURES The rate of detection of pharyngeal cancer, the rates of detection according to the reason for endoscopy, and the types of cancers detected. RESULTS Thirty-eight cancerous lesions were detected in 29 patients (0.26%, 29/11,050). The rate of detection of pharyngeal cancer was significantly higher in patients with a history of head and neck cancer (9.7%, 3/31) or a history of esophageal cancer (3.5%, 10/282). In patients undergoing endoscopy for screening, pharyngeal discomfort, and a history of gastric cancer, the rates of detection of pharyngeal cancer were 0.11% (10/8872), 1.1% (3/265), and 0.19% (3/1600), respectively. Two patients (6.9%) were female. One had a history of esophageal cancer, and the other had pharyngeal discomfort. LIMITATIONS Single-center, retrospective study. CONCLUSIONS Observation of the pharynx by using NBI in patients with previous head and neck cancer or esophageal cancer or who have pharyngeal discomfort is very important. Moreover, pharyngeal cancer was certainly found in the male patients undergoing screening endoscopy, although the rate was lower.

De Novo Emergence of Mesenchymal Stem-Like CD105+ Cancer Cells by Cytotoxic Agents in Human Hepatocellular Carcinoma

BACKGROUND: Cancer stem cells (CSCs) are considered a pivotal target for the eradication of hepatocellular carcinoma (HCC). Recently, we reported that the CSC markers epithelial cell adhesion molecule (EpCAM) and CD90 are expressed independently in primary HCCs and cell lines, and CD90+ cells share features of metastatic vascular endothelial cells and express the vascular endothelial marker CD105, a co-receptor of transforming growth factor-beta. METHODS: The EpCAM+ cell lines HuH1 and HuH7 were treated with 5-fluorouracil (5-FU) or epirubicin in vitro. Gene and protein expression levels were evaluated by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and fluorescence-activated cell sorting, respectively. The expression of CD105 in primary HCC was evaluated by immunohistochemistry. The relationship of CD105 expression status and HCC prognosis was evaluated using 85 surgically resected HCC tissues by Kaplan–Meier survival analysis. RESULTS: 5-FU or epirubicin treatment resulted in the generation of CD90+ and CD105+ cells in vitro in HuH1 and HuH7 cells, which originally contain no CD90+ or CD105+ cells. This phenomenon was validated by qRT-PCR analysis with activation of the epithelial-mesenchymal transition (EMT) program regulators Snail family zinc finger 1 (SNAI1) and SNAI2. Immunohistochemical analysis indicated that CD105+ cells were morphologically identical to vascular endothelial cells in untreated primary HCCs. However, surgically resected specimens after transcatheter arterial chemoembolization clearly indicated that CD105+ cancer cells survived at the peripheral edge of the tumor. Kaplan–Meier survival analysis indicated that HCCs expressing CD105 showed poor prognosis after surgery with statistical significance. CONCLUSIONS: Taken together, our data highlight the role of CD105+ HCC cells with activation of the EMT program generated de novo after cytotoxic therapy on the prognosis of HCC patients.

Use of transoral endoscopy for pharyngeal examination: Cross‐sectional analysis

Transoral endoscopy with narrow band imaging (NBI) is useful for identifying early‐stage head and neck cancer. However, the screening capability of transoral upper gastrointestinal endoscopy has not yet been systematically evaluated. We evaluated the usefulness of transoral upper gastrointestinal endoscopy for pharyngeal examination.

Assessment of still and moving images in the diagnosis of gastric lesions using magnifying narrow-band imaging in a prospective multicenter trial.

Objectives Magnifying narrow-band imaging (M-NBI) is more accurate than white-light imaging for diagnosing small gastric cancers. However, it is uncertain whether moving M-NBI images have additional effects in the diagnosis of gastric cancers compared with still images. Design A prospective multicenter cohort study. Methods To identify the additional benefits of moving M-NBI images by comparing the diagnostic accuracy of still images only with that of both still and moving images. Still and moving M-NBI images of 40 gastric lesions were obtained by an expert endoscopist prior to this prospective multicenter cohort study. Thirty-four endoscopists from ten different Japanese institutions participated in the prospective multicenter cohort study. Each study participant was first tested using only still M-NBI images (still image test), then tested 1 month later using both still and moving M-NBI images (moving image test). The main outcome was a difference in the diagnostic accuracy of cancerous versus noncancerous lesions between the still image test and the moving image test. Results Thirty-four endoscopists were analysed. There were no significant difference of cancerous versus noncancerous lesions between still and moving image tests in the diagnostic accuracy (59.9% versus 61.5%), sensitivity (53.4% versus 55.9%), and specificity (67.0% versus 67.6%). And there were no significant difference in the diagnostic accuracy between still and moving image tests of demarcation line (65.4% versus 65.5%), microvascular pattern (56.7% versus 56.9%), and microsurface pattern (48.1% versus 50.9%). Diagnostic accuracy showed no significant difference between the still and moving image tests in the subgroups of endoscopic findings of the lesions. Conclusions The addition of moving M-NBI images to still M-NBI images does not improve the diagnostic accuracy for gastric lesions. It is reasonable to concentrate on taking sharp still M-NBI images during endoscopic observation and use them for diagnosis. Trial registration Umin.ac.jp UMIN-CTR000008048

Can flat-type brownish microlesions in the orohypopharynx be followed up without biopsy or endoscopic resection?

Narrow‐band imaging (NBI) is useful for detecting superficial oropharyngeal lesions. However, the diagnostic and treatment guidelines for NBI are not established. The aim of the present study was to evaluate the treatment strategy for these microlesions.

Sorafenib suppresses extrahepatic metastasis de novo in hepatocellular carcinoma through inhibition of mesenchymal cancer stem cells characterized by the expression of CD90

Cancer stem cells (CSCs) are a pivotal target for eradicating hepatocellular carcinoma (HCC). We previously reported that distinctive CSCs regulating tumorigenicity (EpCAM+ CSCs) and metastasis (CD90+ CSCs) have different epithelial/mesenchymal gene expression signatures. Here, we examined the influence of sorafenib, a multiple-receptor tyrosine kinase inhibitor used as a first-line treatment for advanced HCC, on EpCAM+ and CD90+ CSCs. CD90+ cells showed higher c-Kit gene/protein expression than EpCAM+ cells. Sorafenib treatment reduced the number of CD90+ cells with attenuated c-Kit phosphorylation, whereas it enriched the EpCAM+ cell population. We evaluated the role of CD90+ and EpCAM+ CSCs in vivo by subcutaneously injecting these CSCs together in immune-deficient mice. We observed that sorafenib subtly affected the suppression of primary tumor growth maintained by EpCAM+ CSCs, but completely inhibited the lung metastasis mediated by CD90+ CSCs. We further evaluated the effect of sorafenib on extracellular vesicle (EV) production and found that sorafenib suppressed the production of EVs containing TGF-β mRNA in CD90+ cells and inhibited the cell-cell communication and motility of EpCAM+ cells. Our data suggest the following novel effects of sorafenib: suppressing CD90+ CSCs and inhibiting the production of EVs regulating distant metastasis.

Lidocaine spray alone is similar to spray plus viscous solution for pharyngeal observation during transoral endoscopy: a clinical randomized trial

Background and study aims It is important to examine the pharynx during upper gastrointestinal endoscopy. Pharyngeal anesthesia using topical lidocaine is generally used as pretreatment. In Japan, lidocaine viscous solution is the anesthetic of choice, but lidocaine spray is applied when the former is considered insufficient. However, the relationship between the extent of pharyngeal anesthesia and accuracy of observation is unclear. We compared the performance of lidocaine spray alone versus lidocaine spray combined with lidocaine viscous solution for pharyngeal observation during transoral endoscopy. Patients and methods In this prospective, double-blinded, randomized clinical trial conducted between January and March 2015, 327 patients were randomly assigned to lidocaine spray alone (spray group, n = 157) or a combination of spray and viscous solution (combination group, n = 170). We compared the number of pharyngeal observable sites (non-inferiority test), pain by visual analogue scale, observation time, and the number of gag reflexes between the two groups. Results The mean number of images of suitable quality taken at the observable pharyngeal sites in the spray group was 8.33 (95 % confidence interval [CI]: 7.94 – 8.72) per patient, and 8.77 (95 % CI: 8.49 – 9.05) per patient in the combination group. The difference in the number of observable pharyngeal sites was – 0.44 (95 % CI: – 0.84 to – 0.03, P = 0.01). There were no differences in pain, observation time, or number of gag reflexes between the 2 groups. Subgroup analysis of the presence of sedation revealed no differences between the two groups for the number of pharyngeal observation sites and the number of gag reflexes. However, the number of gag reflexes was higher in the spray group compared to the combination group in a subgroup analysis that looked at the absence of sedation. Conclusions Lidocaine spray for pharyngeal anesthesia was not inferior to lidocaine spray and viscous solution in terms of pharyngeal observation. It was considered that lidocaine viscous solution was unnecessary for pharyngeal observation. UMIN000016073

Sporadic PCDH18 somatic mutations in EpCAM-positive hepatocellular carcinoma

BackgroundThe relationship between specific genome alterations and hepatocellular carcinoma (HCC) cancer stem cells (CSCs) remains unclear. In this study, we evaluated the relationship between somatic mutations and epithelial cell adhesion molecule positive (EpCAM+) CSCs.MethodsTwo patient-derived HCC samples (HCC1 and HCC2) were sorted by EpCAM expression and analyzed by whole exome sequence. We measured PCDH18 expression level in eight HCC cell lines as well as HCC1 and HCC2 by real-time quantitative RT-PCR. We validated the identified gene mutations in 57 paired of HCC and matched non-cancerous liver tissues by Sanger sequence.ResultsWhole exome sequencing on the sorted EpCAM+ and EpCAM− HCC1 and HCC2 cells revealed 19,263 nonsynonymous mutations in the cording region. We selected mutations that potentially impair the function of the encoded protein. Ultimately, 60 mutations including 13 novel nonsense and frameshift mutations were identified. Among them, PCDH18 mutation was more frequently detected in sorted EpCAM+ cells than in EpCAM− cells in HCC1 by whole exome sequences. However, we could not confirm the difference of PCDH18 mutation frequency between sorted EpCAM+ and EpCAM− cells by Sanger sequencing, indicating that PCDH18 mutation could not explain intracellular heterogeneity. In contrast, we found novel PCDH18 mutations, including c.2556_2557delTG, c.1474C>G, c.2337A>G, and c.2976G>T, were detected in HCC1 and 3/57 (5.3%) additional HCC surgical specimens. All four HCCs with PCDH18 mutations were EpCAM-positive, suggesting that PCDH18 somatic mutations might explain the intertumor heterogeneity of HCCs in terms of the expression status of EpCAM. Furthermore, EpCAM-positive cell lines (Huh1, Huh7, HepG2, and Hep3B) had lower PCDH18 expression than EpCAM-negative cell lines (PLC/PRL/5, HLE, HLF, and SK-Hep-1), and PCDH18 knockdown in HCC2 cells slightly enhanced cell proliferation.ConclusionsOur data suggest that PCDH18 is functionally suppressed in a subset of EpCAM-positive HCCs through somatic mutations, and may play a role in the development of EpCAM-positive HCCs.