MicroRNA expression signature of oral squamous cell carcinoma: functional role of microRNA-26a/b in the modulation of novel cancer pathways.

BACKGROUND: MicroRNAs (miRNAs) have been shown to play major roles in carcinogenesis in a variety of cancers. The aim of this study was to determine the miRNA expression signature of oral squamous cell carcinoma (OSCC) and to investigate the functional roles of miR-26a and miR-26b in OSCC cells. METHODS: An OSCC miRNA signature was constructed by PCR-based array methods. Functional studies of differentially expressed miRNAs were performed to investigate cell proliferation, migration, and invasion in OSCC cells. In silico database and genome-wide gene expression analyses were performed to identify molecular targets and pathways mediated by miR-26a/b. RESULTS: miR-26a and miR-26b were significantly downregulated in OSCC. Restoration of both miR-26a and miR-26b in cancer cell lines revealed that these miRNAs significantly inhibited cancer cell migration and invasion. Our data demonstrated that the novel transmembrane TMEM184B gene was a direct target of miR-26a/b regulation. Silencing of TMEM184B inhibited cancer cell migration and invasion, and regulated the actin cytoskeleton-pathway related genes. CONCLUSIONS: Loss of tumour-suppressive miR-26a/b enhanced cancer cell migration and invasion in OSCC through direct regulation of TMEM184B. Our data describing pathways regulated by tumour-suppressive miR-26a/b provide new insights into the potential mechanisms of OSCC oncogenesis and metastasis.

Identification of tumour suppressive microRNA-451a in hypopharyngeal squamous cell carcinoma based on microRNA expression signature.

BACKGROUND: Hypopharyngeal squamous cell carcinoma (HSCC) has a very poor prognosis because of its high rates of regional and distant metastasis. Identification of differentially expressed miRNAs and their regulated molecular targets in tumour cells might enhance our understanding of the molecular mechanisms of metastasis in human cancers. METHODS: A HSCC miRNA signature was constructed by array-based methods. Functional studies of microRNA-451a (miR-451a) and target genes were performed to investigate cell proliferation, migration and invasion by cancer cell lines. To identify miR-451a-regulated molecular targets, we adopted gene expression analysis and in silico database analysis. RESULTS: Our miRNA signature revealed that miR-451a was significantly downregulated in HSCC. Restoration of miR-451a in cancer cell lines revealed that this miRNA significantly inhibited cancer cell migration and invasion. Our data demonstrated that the gene coding for endothelial and smooth muscle cell-derived neuropilin-like molecule (ESDN/DCBLD2) was a direct target of miR-451a regulation. Silencing of ESDN inhibited cell migration and invasion by cancer cells. CONCLUSIONS: Loss of tumour suppressive miR-451a enhanced cancer cell migration and invasion in HSCC through direct regulation of ESDN. Our miRNA signature and functional analysis of targets regulated by tumour suppressive miR-451a provide new insights into the potential mechanisms of HSCC oncogenesis and metastasis.

Tumour-suppressive microRNA-29s inhibit cancer cell migration and invasion by targeting laminin-integrin signalling in head and neck squamous cell carcinoma.

BACKGROUND: Our recent studies of microRNA (miRNA) expression signatures demonstrated that microRNA-29s (miR-29s; miR-29a/b/c) were significantly downregulated in head and neck squamous cell carcinoma (HNSCC) and were putative tumour-suppressive miRNAs in human cancers. Our aim in this study was to investigate the functional significance of miR-29s in cancer cells and to identify novel miR-29s-mediated cancer pathways and responsible genes in HNSCC oncogenesis and metastasis. METHODS: Gain-of-function studies using mature miR-29s were performed to investigate cell proliferation, migration and invasion in two HNSCC cell lines (SAS and FaDu). To identify miR-29s-mediated molecular pathways and targets, we utilised gene expression analysis and in silico database analysis. Loss-of-function assays were performed to investigate the functional significance of miR-29s target genes. RESULTS: Restoration of miR-29s in SAS and FaDu cell lines revealed significant inhibition of cancer cell migration and invasion. Gene expression data and in silico analysis demonstrated that miR-29s modulated the focal adhesion pathway. Moreover, laminin γ2 (LAMC2) and α6 integrin (ITGA6) genes were candidate targets of the regulation of miR-29s. Luciferase reporter assays showed that miR-29s directly regulated LAMC2 and ITGA6. Silencing of LAMC2 and ITGA6 genes significantly inhibited cell migration and invasion in cancer cells. CONCLUSION: Downregulation of miR-29s was a frequent event in HNSCC. The miR-29s acted as tumour suppressors and directly targeted laminin-integrin signalling. Recognition of tumour-suppressive miRNA-mediated cancer pathways provides new insights into the potential mechanisms of HNSCC oncogenesis and metastasis and suggests novel therapeutic strategies for the disease.

Tumour-suppressive microRNA-874 contributes to cell proliferation through targeting of histone deacetylase 1 in head and neck squamous cell carcinoma.

BACKGROUND: Our recent studies of microRNA (miRNA) expression signature demonstrated that microRNA-874 (miR-874) was significantly downregulated in maxillary sinus squamous cell carcinoma (MSSCC), and a putative tumour-suppressive miRNA in human cancers. Our aim of this study was to investigate the functional significance of miR-874 in cancer cells and to identify novel miR-874-mediated cancer pathways and responsible genes in head and neck squamous cell carcinoma (HNSCC). METHODS: Gain-of-function studies using mature miR-874 were performed to investigate cell proliferation and cell cycle distribution in HNSCC cell lines (SAS and FaDu). To identify miR-874-mediated molecular pathways and targets, we utilised gene expression analysis and in silico database analysis. Loss-of-function assays were performed to investigate the functional significance of miR-874 target genes. RESULTS: Expression levels of miR-874 were significantly downregulated in HNSCC tissues (including oral, pharyngeal and laryngeal SCCs) compared with normal counterpart epithelia. Restoration of miR-874 in SAS and FaDu cell lines revealed significant inhibition of cell proliferation and induction of G2/M arrest and cell apoptosis. Our expression data and in silico analysis demonstrated that miR-874 modulated the cell cycle pathway. Moreover, histone deacetylase 1 (HDAC1) was a candidate target of miR-874 regulation. Luciferase reporter assays showed that miR-874 directly regulated HDAC1. Silencing of the HDAC1 gene significantly inhibited cell proliferation and induced G2/M arrest and cell apoptosis in SAS cells. CONCLUSIONS: Downregulation of miR-874 was a frequent event in HNSCC. miR-874 acted as a tumour suppressor and directly targeted HDAC1. Recognition of tumour-suppressive miRNA-mediated cancer pathways provides new insights into the potential mechanisms of HNSCC oncogenesis and suggests novel therapeutic strategies for the disease.

Tumour suppressive microRNA-874 regulates novel cancer networks in maxillary sinus squamous cell carcinoma.

BACKGROUND: On the basis of the microRNA (miRNA) expression signature of maxillary sinus squamous cell carcinoma (MSSCC), we found that miR-874 was significantly reduced in cancer cells. We focused on the functional significance of miR-874 in cancer cells and identification of miR-874-regulated novel cancer networks in MSSCC. METHODS: We used PCR-based methods to investigate the downregulated miRNAs in clinical specimens of MSSCC. Our signature analyses identified 23 miRNAs that were significantly reduced in cancer cells, such as miR-874, miR-133a, miR-375, miR-204, and miR-1. We focused on miR-874 as the most downregulated novel miRNA in our analysis. RESULTS: We found potential tumour suppressive functions such as inhibition of cancer cell proliferation and invasion. A molecular target search of miR-874 revealed that PPP1CA was directly regulated by miR-874. Overexpression of PPP1CA was observed in MSSCC clinical specimens. Silencing of the PPP1CA gene significantly inhibited cancer cell proliferation and invasion. CONCLUSION: The downregulation of miR-874 was a frequent event in MSSCC, which suggests that miR-874 functions as a tumour suppressive miRNA, directly regulating PPP1CA that has a potential role of an oncogene. The identification of novel miR-874-regulated cancer pathways could provide new insights into potential molecular mechanisms of MSSCC oncogenesis.

LY6K is a novel molecular target in bladder cancer on basis of integrate genome-wide profiling.

BACKGROUND: The aim of this study is to find a novel molecular target based on chromosomal alteration and array-based gene expression analyses in bladder cancer (BC). We investigated a cancer testis antigen, LY6K, which is located on chromosome 8q24.3. METHODS: Five BC cell lines were subjected to high-resolution array-comparative genomic hybridisation with 244 000 probes. The expression levels of LY6K mRNA were evaluated in BC cell lines and clinical BC specimens by real-time reverse transcription-PCR. The cell lines were subjected to fluorescence in situ hybridisation of LY6K. Cell viability was evaluated by cell growth, wound healing, and matrigel invasion assays. RESULTS: Typical gained loci (P<0.0001) at 6p21.33-p21.32, 8q24.3, 9q34.13, 11q13.1-q14.1, 12q13.12-q13.13, 16p13.3, and 20q11.21-q13.33 were observed in all of the cell lines. We focused on 8q24.3 locus where LY6K gene harbours, and it was the top upregulated one in the gene profile from the BC cell line. LY6K mRNA expression was significantly higher in 91 BCs than in 37 normal bladder epitheliums (P<0.0001). Fluorescence in situ hybridisation validated that the high LY6K mRNA expression was due to gene amplification in the region where the gene harbours. Cell viability assays demonstrated that significant inhibitions of cell growth, migration, and invasion occured in LY6K knock down BC cell lines; converse phenomena were observed in a stable LY6K transfectant; and LY6K knockdown of the transfectant retrieved the original phenotype from the LY6K transfectant. CONCLUSION: Upregulation of the oncogenic LY6K gene located on the gained locus at 8q24.3 may contribute BC development.

miR-489 is a tumour-suppressive miRNA target PTPN11 in hypopharyngeal squamous cell carcinoma (HSCC).

BACKGROUND: Hypopharyngeal squamous cell carcinoma (HSCC) is an aggressive malignancy with one of the worst prognoses among all head and neck cancers. Greater understanding of the pertinent molecular oncogenic pathways could help improve diagnosis, therapy, and prevention of this disease. The aim of this study was to identify tumour-suppressive microRNAs (miRNAs), based on miRNA expression signatures from clinical HSCC specimens, and to predict their biological target genes. METHODS: Expression levels of 365 human mature miRNAs from 10 HSCC clinical samples were screened using stem-loop real-time quantitative PCR. Downregulated miRNAs were used in cell proliferation assays to identify a tumour-suppressive miRNA. Genome-wide gene expression analyses were then performed to identify the target genes of the tumour-suppressive miRNA. RESULTS: Expression analysis identified 11 upregulated and 31 downregulated miRNAs. Gain-of-function analysis of the downregulated miRNAs revealed that miR-489 inhibited cell growth in all head and neck cancer cell lines examined. The gene PTPN11 coding for a cytoplasmic protein tyrosine phosphatase containing two Src Homology 2 domains was identified as a miR-489-targeted gene. Knockdown of PTPN11 resulted in the inhibition of cell proliferation in head and neck SCC cells. CONCLUSION: Identification of the tumour-suppressive miRNA miR-489 and its target, PTPN11, might provide new insights into the underlying molecular mechanisms of HSCC.

miR-145 and miR-133a function as tumour suppressors and directly regulate FSCN1 expression in bladder cancer.

BACKGROUND: We have recently identified down-regulated microRNAs including miR-145 and miR-133a in bladder cancer (BC). The aim of this study is to determine the genes targeted by miR-145, which is the most down-regulated microRNA in BC. METHODS: We focused on fascin homologue 1 (FSCN1) from the gene expression profile in miR-145 transfectant. The luciferase assay was used to confirm the actual binding sites of FSCN1 mRNA. Cell viability was evaluated by cell growth, wound-healing, and matrigel invasion assays. BC specimens were subjected to immunohistochemistry of FSCN1 and in situ hybridisation of miR-145. RESULTS: The miR-133a as well as miR-145 had the target sequence of FSCN1 mRNA by the database search, and both microRNAs repressed the mRNA and protein expression of FSCN1. The luciferase assay revealed that miR-145 and miR-133a were directly bound to FSCN1 mRNA. Cell viability was significantly inhibited in miR-145, miR-133a, and si-FSCN1 transfectants. In situ hybridisation revealed that miR-145 expression was markedly repressed in the tumour lesion in which FSCN1 was strongly stained. The immunohistochemical score of FSCN1 in invasive BC (n=46) was significantly higher than in non-invasive BC (n=20) (P=0.0055). CONCLUSION: Tumour suppressive miR-145 and miR-133a directly control oncogenic FSCN1 in BC.

Expression and mutation of SMAD4 in poorly differentiated carcinoma and signet-ring cell carcinoma of the colorectum.

Poorly differentiated adenocarcinoma (Por) and signet-ring cell carcinoma (Sig) are rare but highly malignant types of colorectal cancer. To explore their genetic backgrounds we investigated TGF-beta type II receptor (TGF-beta RII) and SMAD4 in the TGF-beta signaling pathway, and to identify their mutator phenotype we examined microsatellite instability (MSI) status. Loss of SMAD4 expression was significantly more frequent in Por (12 of 38; 31%) and Sig (4 of 5; 80%) tumors than in well (Well) and moderately differentiated (Mod) carcinomas (p = 0.04, 0.003, respectively). Mutation of the SMAD4 gene was detected in 2 of 26 Por tumors. MSI was positive in 14 of the 38 Por tumors and in 1 of the 5 Sig tumors, but in none of the Well or Mod tumors examined. We also found mutation of TGF-beta RII, a putative target of MSI, in 10 of 35 Por tumors (28.6%), but in none of 3 Sig tumors. As a whole, about 50% of the Por tumors and 80% of the Sig tumors showed abnormalities of either TGF-beta RII or SMAD4 expression. This suggests that disruption of the TGF-beta signaling pathway may play a central role in the pathogenesis of Por and Sig tumors of the colorectum.

Metastatic breast cancer with resistance to both anthracycline and docetaxel successfully treated with weekly paclitaxel.

We report the case of a 38-year-old woman who underwent surgery for stage III-b breast cancer, and whose liver metastasis failed to respond to both docetaxel (administered at 30-40 mg/m2 every 2 weeks as a 1-h intravenous infusion) and epirubicin (administered as a 40-60 mg/m2 bolus hepatic arterial infusion). For subsequent treatment, this patient was managed with weekly paclitaxel. The regimen showed some usefulness for the treatment of the liver metastasis, as indicated by an improvement in performance status and tolerable toxicity. This case demonstrates that weekly paclitaxel may be well tolerated and useful for patients with extensive metastatic breast cancer that was resistant to treatment. Our findings also suggest that paclitaxel could be used as a salvage therapy in patients with anthracycline- and docetaxel-resistant breast cancer.

A case of basal cell carcinoma of the nipple and areola with intraductal spread.

We report an 82-year-old Japanese woman with basal cell carcinoma of the left nipple and areola extending into the lactiferous duct. The patient developed a small papular lesion of the left areola about 1 year before admission. The lesion, which had slowly progressed to involve the nipple, had become symptomatic showing weeping and bleeding. Mammography revealed microcalcification in the nipple. Although Paget's disease was suspected from these clinical features, histologically basal cell carcinoma was diagnosed. There was no axillary lymphadenopathy, and no evidence of distant metastasis. The lesion of the nipple and areola was resected with a 2 cm free margin along with the underlying mammary tissue. The patient has remained well without signs of recurrence for 2 years after surgery. We reviewed cases of basal cell carcinoma of the nipple or areola and discuss considerations and problems of this rare tumor.

New technique of laparoscopic-assisted excision of a cholecystocolic fistula: report of a case.

Cholecystocolic fistula is a rare complication of gallstone disease that is most commonly diagnosed at the time of surgery. It is generally considered to be a contraindication to laparoscopic cholecystectomy because of the difficulties involved in its management intraoperatively. Laparoscopic stapling or suturing techniques have been reported as feasible and safe methods for repairing such fistulas; however, these procedures are not always able to be performed due to technical difficulties. We exteriorized a cholecystocolic fistula through an umbilical incision, whereby it was repaired safely and easily. This report describes our new technique for managing a cholecystocolic fistula found incidentally during a laparoscopic cholecystectomy.

[Clinical results of concurrent chemoradiation therapy for primary highly advanced esophageal cancer].

Clinical results after non-curative resection of highly advanced esophageal cancer are extremely poor. We administered concurrent chemoradiation therapy (CRT) as a multidisciplinary therapy in cases of highly advanced esophageal cancer for which non-curative resection is expected. The efficacy rate of the therapy was 59.4%, and the 3-year-survival rate 10.2%. A life-prolonging effect (the 3-year survival being 17.9%) was observed in the effective cases. Our future aim is to establish a safer, more reliable and cost-effective therapy by estimating the degree of efficacy before administration of CRT and then selecting cases suitable for CRT.

Carcinoma of the head of the pancreas after excision of a choledochal cyst.

We here report a 53-year-old woman who had undergone resection of a choledochal cyst and hepaticojejunostomy three years before. She was readmitted because of intermittent fever, and abdominal computed tomography revealed a 4-cm tumor in the head of the pancreas. We performed pancreatoduodenectomy, and examination of the resected specimen showed well-differentiated papillary adenocarcinoma. Only 5 cases of carcinoma occurring after the resection of a choledochal cyst have been reported, and to our knowledge, this is the second case of carcinoma of the head of the pancreas.

[Development of neck filters for reducing artifact in cervical bone SPECT].

In cervical bone scintillation SPECT studies using TEW and OS-EM methods, we have observed an artifact that may interfere with evaluation of the image; higher accumulation in cervical vertebra compared with in the head and thoracic vertebra. As the neck is smaller in diameter than in the thorax and head, gamma ray absorption is lower. In addition, as the distance between the neck and the detector is greater, scattered gamma rays are increased, interfering with imaging and causing artifact. To overcome these problems, we have developed special absorbers (neck filter) to make the relative absorption level of the neck comparable to that of the head and thorax and have employed these cervical filters in bone scintillation SPECT studies in combination with TEW scatter correction and OS-EM method. Our results showed that artifacts were significantly reduced and satisfactory images were obtained.

Prognostic factors for recurrence in stage II and III gastric cancer patients receiving a curative resection and postoperative adjuvant chemotherapy.

Prognostic value of clinicopathologic factors and biologic markers was analyzed in 185 patients who received a curative resection and adjuvant chemotherapy of pathologically confirmed stage II or III gastric cancer. No difference was found between the chemotherapeutic regimens according to the frequency of recurrence, but tumor type, histology, depth of invasion, nodal metastasis, and lymphatic and venous invasion were significantly different between recurrent (n=62) and non-recurrent (n=123) patients. However, the degree of lymphatic dissection and the patterns of biological markers (DNA ploidy, p53 staining and PCNA labeling) were not different. Hepatic metastasis and venous invasion were more frequent on patients recurring within one year, compared to those who recurred later. Multivariate analyses showed that depth of invasion, level 2 lymph node metastasis and tumor histology were risk factors for recurrence. Pathologic factors were more important for predicting recurrence than biological markers.

Synchronous rectal and esophageal cancer associated with prurigo chronica multiformis: report of a case.

The skin lesions that appear in association with internal malignancies are called dermadromes or paraneoplastic cutaneous disorders. These skin changes characteristically develop with progression of the internal malignancy. A 75-year-old Japanese man who had been diagnosed as having prurigo chronica multiformis, a form of dermadrome, 5 years previously was referred to our hospital for further investigation. On admission, numerous itchy red papules were present on the right side of the abdomen and the inner aspect of both thighs. Intensive screening for internal malignancies revealed advanced rectal cancer and early esophageal cancer. After surgical resection, the skin lesions improved without any treatment. To the best of our knowledge, this is the first case of synchronous double cancers associated with prurigo chronica multiformis.

[Case report--efficacy of short-term intraarterial 5-fluorouracil for liver metastasis from colorectal cancer].

Hepatectomy has the highest cure rate among the various methods for treating liver metastasis from colorectal cancer. We previously reported that continuous hepatic arterial infusion (HAI) of 5-FU is effective for improving the prognosis of patients with liver metastasis. In this study, we examined the efficacy of short-term continuous HAI of 5-FU for treating liver metastasis from colorectal cancer. A 57-year-old woman with a solitary liver metastasis from rectal cancer was treated by continuous HAI of 5-FU (1,000 mg/day) for 6 days. Her elevated serum CEA level (20.7 ng/ml) then returned to normal. Computed tomography revealed a decrease of 55.6% in the size of the liver tumor. Partial segmentectomy (S7) was subsequently performed. Histological examination of the resected tumor showed marked degeneration, necrosis, fibrosis, and calcification with viable moderately differentiated adenocarcinoma cells. These results suggest that preoperative HAI of 5-FU is safe and worth trying in patients with liver metastasis from colorectal cancer.

[Microwave coagulation therapy for liver recurrence after resection of metastatic colorectal cancer--comparison with re-hepatectomy].

One hundred and fifty-three patients with liver metastases from colorectal cancer underwent hepatectomy from 1979 to 1998. Recurrence in the residual liver occurred in 71 of the 129 patients with curative B resection, and re-hepatectomy has been done in 21 of these 71 patients since 1984. The 5-year survival rate is 37.0%. MCT has been performed in ten of these 71 patients who could not undergo re-hepatectomy and one patient received both therapies. The 3-year survival rate is 66.7%, which is statistically better than that of 35 patients who could not undergo re-hepatectomy before we started MCT (3-year survival rate of 20.0%). Re-hepatectomy is quite effective for recurrent liver remetastasis after hepatectomy, and MCT is probably of similar value.

[Efficacy of combination therapy for multiple liver metastases of colorectal cancer].

In our hospital, combination therapy, mainly intra-arterial infusion, is performed for multiple liver metastases of colorectal cancer. The median survival time of the combination group (n = 18), the hepatectomy only group (n = 3) and the best supportive care group (n = 7) were 21.7, 12.5 and 6.1 months, respectively. The prognosis of the combination group was significantly better than that in the other groups (p < 0.0001). Univariate analysis against the combination group revealed that serum CEA was a significant prognostic factor (p = 0.0196). Moreover, we divided the combination group into two groups on the basis of serum CEA either below or above 50 ng/ml. The prognosis of the low CEA group (n = 11), whose median survival time was 25.9 months, was significantly better than the high CEA group (n = 7), whose median survival time was 17.8 months (p = 0.0031). It therefore appears that combination therapy may be of no benefit when serum CEA is above 50 ng/ml.