Tomoko Hashimoto-Tamaoki

Successful Chemotherapeutic Modality of Doxorubicin Plus Dacarbazine for the Treatment of Desmoid Tumors in Association With Familial Adenomatous Polyposis

PURPOSE Desmoid tumors are locally aggressive and can be fatal in familial adenomatous polyposis (FAP) patients if they are not suitable for surgery or radiation therapy. Here, we prospectively investigated the efficacy of a chemotherapeutic regimen involving doxorubicin (DOX) and dacarbazine (DTIC) for inoperable FAP-associated desmoid tumors. PATIENTS AND METHODS From an initial group of 120 FAP patients, seven of the 11 individuals with symptomatic unresectable desmoid tumors that were unresponsive to conventional hormone therapy were enrolled onto this study. The general chemotherapy regimen comprised four or five cycles of DOX (20 mg/m2 daily) plus DTIC (150 mg/m2 daily) throughout 4 days of drip intravenous infusion (day 1 through 4) every 28 days, followed by the cyclooxygenase-2 inhibitor meloxicam (10 mg/m2). The primary end point was relapse-free survival. The secondary end points included toxicity, clinical improvement, and tumor regression according to computed tomography. RESULTS Significant tumor regression was observed clinically and radiologically in all seven patients. Three patients showed a complete response. The average progression-free survival period was 74.0 months (range, 32.5 to 107.5 months). Three patients showed grade 3 adverse events with no treatment-related mortality. All seven patients survived and remained without tumor progression. An adenomatous polyposis coli germline-mutation analysis revealed no mutations in the specified regions. CONCLUSION A chemotherapeutic regimen of DOX plus DTIC followed by meloxicam is an effective and safe treatment for FAP-associated desmoid tumors. This modality should be considered for use as first-line chemotherapy in symptomatic desmoid tumors that are unresponsive to conventional medical therapy, due to the absence of useful presymptomatic markers.

Frequent inactivation of the BAP1 gene in epithelioid-type malignant mesothelioma.

In the present study, we analyzed genomic alterations of BRCA1‐associated protein 1 (BAP1) in 23 malignant mesotheliomas (MMs), 16 epithelioid and seven non‐epithelioid, consisting of 18 clinical specimens and five established cell lines. In examining these samples for homozygous deletions and sequence‐level mutations, we found biallelic BAP1 gene alterations in 14 of 23 MMs (61%). Seven of these 14 MMs had homozygous deletions of the partial or entire BAP1 gene, another five had sequence‐level mutations, including small deletions, a nonsense mutation, and missense mutations with additional monoallelic deletions, and the remaining two had homozygous mutations without allelic loss. All but one of the 14 BAP1 gene mutations were found in the epithelioid‐type MMs; BAP1 mutations were found in 13 of 16 epithelioid‐type MMs, but in only one of seven non‐epithelioid‐type MMs (13/16 vs 1/7; P = 0.005). There was no BAP1 mRNA expression in MMs with biallelic deletion and repressed expression was confirmed in MM specimens with deletion/mutation as compared with Met5a, SV40‐transformed normal mesothelial cells. Western blot showed that seven of eight epithelioid MMs analyzed were BAP1 negative. Immunostaining with anti‐BAP1 antibody in normal lung tissues revealed clear nuclear staining of normal mesothelial cells. No nuclear staining was observed among BAP1 mutation‐positive MM tumors, whereas nuclear staining was observed among BAP1 mutation‐negative MM tumors. These results suggest that the lack of the tumor suppressor BAP1 may be more specifically involved in the pathogenesis of epithelioid MM rather than non‐epithelioid MM, and would be useful for diagnosis of epithelioid‐type MM. (Cancer Sci 2012; 103: 868–874)

Suppression of growth of hepatocellular carcinoma by sodium butyrate in vitro and in vivo

Treatment of HuH‐7 human hepatocellular carcinoma (HCC) cells with 1–10 mM sodium butyrate (SB) resulted in growth inhibition in a dose‐dependent manner. At 3 mM and higher concentrations, SB caused nuclear fragmentation and DNA ladder formation characteristic of apoptosis. In the treated cells, the expression of p21 (WAF1/CIP1) increased and that of α‐fetoprotein (AFP) decreased. These characteristic changes were also observed with 5 other human HCC cell lines with or without mutation of the p53 gene. The ability of these cells to form colonies in soft agar was suppressed by either pretreating the cells with SB prior to soft agar plating or incubating untreated cells in SB‐containing soft agar. Direct injection of SB into tumors developed from HuH‐7 cells in nude mice resulted in an increase in the p21 level, a decrease in the tumor size and an increase in the survival time of mice. When the inoculation of HuH‐7 cells into nude mice was immediately followed by subcutaneous injection of SB, development of tumors was either significantly delayed or completely suppressed. These results suggest that SB induces cellular differentiation and suppresses growth and tumorigenicity of HCC cells in vitro and in vivo by a mechanism independent of p53 but possibly dependent on p21. Int. J. Cancer 76:897–902, 1998.© 1998 Wiley‐Liss, Inc.

Hepatocyte growth factor promotes migration of human hepatocellular carcinoma via phosphatidylinositol 3-kinase.

Hepatocyte growth factor (HGF) is known to be a potent mitogen and motogen for epithelial cells. Hepatocellular carcinoma (HCC) often metastasizes, and the c-Met/HGF receptor is highly expressed by HCC cells. The aim of this study was to investigate the signaling pathways associated with the motogenic effect of HGF on HCC cells via c-Met. HCC cell lines (Hep3B, HepG2, PLC, and Huh-7) and HCC cells harvested from patients were used for the Boyden chamber assay of chemotactic activity as well as for immunoprecipitation and immunoblotting studies. HGF stimulated the motility of Hep3B, HepG2, and Huh-7 cells in a dose-dependent manner in association with tyrosine phosphorylation of c-Met and activation of phosphatidylinositol 3-kinase (PI3-K). A tyrosine kinase inhibitor (genistein) and a PI3-K inhibitor (wortmannin) prevented the migration of HCC cells. However, migration was not prevented by calphostin C, an inhibitor of protein kinase C (PKC), which is a downstream target of phospholipase Cγ (PLCγ). HGF also stimulated the migration of HCC cells obtained from three patients, while wortmannin prevented the migration of these cells. These results indicate that HGF stimulates the migration of HCC cells through the tyrosine phosphorylation of c-Met via activation of PI3-K.

Hedgehog signal activation in oesophageal cancer patients undergoing neoadjuvant chemoradiotherapy.

The zinc finger protein glioma-associated oncogene homologue 1 (Gli-1) is a critical component of the Hedgehog (Hh) signalling pathway, which is essential for morphogenesis and stem-cell renewal, and is dysregulated in many cancer types. As data were not available on the role of Gli-1 expression in oesophageal cancer progression, we analysed whether it could be used to predict disease progression and prognosis in oesophageal cancer patients undergoing neoadjuvant chemoradiotherapy (CRT). Among 69 patients with histologically confirmed oesophageal squamous cell carcinomas (ESCCs), 25 showed a pathological complete response after preoperative CRT. Overall survival (OS) was significantly associated with lymph-node metastasis, distant metastasis, and CRT, and was further correlated with the absence of both Gli-1 nuclear expression and residual tumour. All patients with Gli-1 nuclear expression (10.1%) had distant or lymph-node metastasis, and six out of seven died within 13 months. Furthermore, patients with Gli-1 nuclear-positive cancers showed significantly poorer prognoses than those without (disease-free survival: mean DFS time 250 vs 1738 months, 2-year DFS 0 vs 54.9%, P=0.009; OS: mean OS time 386 vs 1742 months, 2-year OS 16.7 vs 54.9%, P=0.001). Our study provides the first evidence that Gli-1 nuclear expression is a strong and independent predictor of early relapse and poor prognosis in ESCC after CRT. These findings suggest that Hh signal activation might promote cancer regrowth and progression after CRT.

Positive and negative regulation of myogenic differentiation of C2C12 cells by isoforms of the multiple homeodomain zinc finger transcription factor ATBF1.

The ATBF1 gene encodes two protein isoforms, the 404-kDa ATBF1-A, possessing four homeodomains and 23 zinc fingers, and the 306-kDa ATBF1-B, lacking a 920-amino acid N-terminal region of ATBF1-A which contains 5 zinc fingers. In vitro, ATBF1-A was expressed in proliferating C2C12 myoblasts, but its expression levels decreased upon induction of myogenic differentiation in low serum medium. Forced expression of ATBF1-A in C2C12 cells resulted in repression of MyoD and myogenin expression and elevation of Id3 and cyclin D1 expression, leading to inhibition of myogenic differentiation in low serum. In contrast, transfection of C2C12 cells with the ATBF1-B isoform led to an acceleration of myogenic differentiation, as indicated by an earlier onset of myosin heavy chain expression and formation of a higher percentage of multinucleated myotubes. The fourth homeodomain of ATBF1-A bound to an AT-rich element adjacent to the E1 E-box of the muscle regulatory factor 4 promoter mediating transcriptional repression. The ATBF1-A-specific N-terminal region possesses general transcription repressor activity. These results suggest that ATBF1-A plays a role in the maintenance of the undifferentiated myoblast state, and its down-regulation is a prerequisite to initiate terminal differentiation of C2C12 cells.

Expression and role of p27kip1 in neuronal differentiation of embryonal carcinoma cells

Abstract We examined the expression and the regulation of p21 waf1 and p27 kip1 cdk inhibitors in P19 mouse embryonal carcinoma (EC) cells following treatment with all- trans retinoic acid (ATRA) to induce neuronal differentiation. The levels of p27 mRNA and protein increased within 24 h of treatment with ATRA, reaching a plateau 4–5 days later prior to neurite formation. In contrast, levels of p21 expression remained low until after neurites were extensively formed. Induction of muscle differentiation from P19 cells by treatment with dimethyl sulfoxide caused only transient increases in p27 levels. In a mutant P19 cell line, RAC65, treatment with ATRA induced neither p27 accumulation nor neuronal differentiation, but p21 mRNA expression increased markedly. In contrast, treatment of RAC65 cells with 9- cis retinoic acid induced both p27 expression and neuronal differentiation. Correlation between p27 expression and neuronal differentiation was also observed in NT2/D1 human EC cells. Luciferase reporter assays showed that p27 promoter activity increased in ATRA-treated cells, consistent with the elevation of p27 mRNA levels. Arrest of neuronal differentiation of P19 cells by okadaic acid resulted in inhibition of p27 expression, whereas p21 mRNA expression was greatly enhanced. Conversely, inhibition of p27 expression by antisense p27 oligonucleotides resulted in blockade of neuronal differentiation. Taken together, these results strongly suggest that the expression of p27 is indispensable for neuronal differentiation of EC cells.

ATBF1-A protein, but not ATBF1-B, is preferentially expressed in developing rat brain.

The ATBF1 gene encodes transcription factors containing four homeodomains and multiple zinc finger motifs. However, the gene products have yet to be identified and the role remains unknown in vivo. In this study, we raised an antiserum for ATBF1 and found high levels of expression of ATBF1 in developing rat brain. Western and Northern blot analyses detected a 400 kDa protein and 12.5 kb mRNA in developing rat brain, respectively; both corresponding to ATBF1‐A but not the B isoform. The protein was highly expressed in the midbrain and diencephalon and mRNA was highly expressed in the brainstem, mostly in embryo and neonatal brain. Immunohistochemistry identified postmitotic neurons in the brainstem as the major site of ATBF1 expression, and the expression levels varied depending on age of and location in the brain. Expression was transient and weak in the precursor cells at early neurogenesis. ATBF1 decreased postnatally, but remained in mature neurons, including those expressing DOPA decarboxylase (DDC). High levels of ATBF1 were expressed in precursor cells in accordance with neurogenesis and were continued to the mature neurons in specific areas such as the inferior colliculus. Expression was not significant from precursor cells to mature neurons in the cerebral cortex and hippocampus. ATBF1 and its Drosophila homolog, Zfh‐2, are known to regulate cell differentiation and proliferation via the interaction with either of the basic helix‐loop‐helix transcription factors, c‐myb, or the DDC gene. Together with these reported functions the expression features detected here suggest that ATBF1 may participate in the regulation of neuronal cell maturation or region‐specific central nervous system differentiation. J. Comp. Neurol. 465:57–71, 2003.

High-density array-CGH with targeted NGS unmask multiple noncontiguous minute deletions on chromosome 3p21 in mesothelioma

Significance We found that gene mutations/deletions are frequent in mesothelioma and occur through a variety of DNA alterations. We identified genes implicated in malignant mesothelioma: SETD2, SMARCC1, PBRM1. Previous next-generation studies (NGS) underestimated the frequency of genetic alterations in malignant mesothelioma because NGS mainly identifies nucleotide level mutations. Our findings are of general relevance to the field of cancer research that relies almost exclusively on NGS to identify gene alterations in cancer biopsies, and uses this information to design specific molecular therapies. An integrated approach that includes a high-density comparative genomic hybridization array and NGS or targeted-NGS, as conducted here, may reveal additional genes that are inactivated by mechanisms other than point mutations. This information may inform us on how to design more effective molecular therapies. We used a custom-made comparative genomic hybridization array (aCGH; average probe interval 254 bp) to screen 33 malignant mesothelioma (MM) biopsies for somatic copy number loss throughout the 3p21 region (10.7 Mb) that harbors 251 genes, including BRCA1 (breast cancer 1)-associated protein 1 (BAP1), the most commonly mutated gene in MM. We identified frequent minute biallelic deletions (<3 kb) in 46 of 251 genes: four were cancer-associated genes: SETD2 (SET domain-containing protein 2) (7 of 33), BAP1 (8 of 33), PBRM1 (polybromo 1) (3 of 33), and SMARCC1 (switch/sucrose nonfermentable- SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily c, member 1) (2 of 33). These four genes were further investigated by targeted next-generation sequencing (tNGS), which revealed sequence-level mutations causing biallelic inactivation. Combined high-density aCGH and tNGS revealed biallelic gene inactivation in SETD2 (9 of 33, 27%), BAP1 (16 of 33, 48%), PBRM1 (5 of 33, 15%), and SMARCC1 (2 of 33, 6%). The incidence of genetic alterations detected is much higher than reported in the literature because minute deletions are not detected by NGS or commercial aCGH. Many of these minute deletions were not contiguous, but rather alternated with segments showing oscillating copy number changes along the 3p21 region. In summary, we found that in MM: (i) multiple minute simultaneous biallelic deletions are frequent in chromosome 3p21, where they occur as distinct events involving multiple genes; (ii) in addition to BAP1, mutations of SETD2, PBRM1, and SMARCC1 are frequent in MM; and (iii) our results suggest that high-density aCGH combined with tNGS provides a more precise estimate of the frequency and types of genes inactivated in human cancer than approaches based exclusively on NGS strategy.

The Hippo pathway transcriptional co-activator, YAP, confers resistance to cisplatin in human oral squamous cell carcinoma

Cisplatin (CDDP) is widely used to treat oral squamous cell carcinoma (OSCC), however, many patients exhibit acquired drug resistance. Yes-associated protein (YAP) is a transcriptional co-activator of the Hippo pathway that regulates organ size and promotes cell proliferation. YAP overexpression correlates with epithelial-mesenchymal transition and nodal metastasis, resulting in anti-tubulin drug resistance. Whether YAP overexpression is the cause of CDDP resistance in cancer cells is unclear, therefore, we investigated the correlation between YAP expression and CDDP sensitivity. We established three CDDP-resistant cell lines (OSC-19-R, SCCKN-R and HSC-3-R) from the OSCC parental cell lines. We also examined the expression levels of ATP7B, GST-π and ERCC1, which are strongly associated with CDDP resistance, and Hippo pathway-related proteins by western blotting. Using immunocytochemistry, we examined the cellular localization of YAP. Additionally, following knockdown of YAP using short interfering RNAs (siRNAs), we analyzed changes in sensitivity to CDDP. Compared with parental OSC-19 cells, OSC-19-R cells were obviously larger. Expression levels of YAP were not significantly different between OSC-19 and OSC-19-R. However, expression levels of phosphorylated YAP in OSC-19-R were decreased. We observed translocation of YAP from the cytoplasm to the nucleus in OSC-19-R cells. Knockdown of YAP using siRNAs revealed that sensitivity to CDDP was significantly increased. Translocation of YAP correlated with the acquisition of CDDP resistance. YAP could be a new therapeutic target for the treatment of patients with cancer that are resistant to CDDP.