Huang-Chun Lien

ERK promotes tumorigenesis by inhibiting FOXO3a via MDM2-mediated degradation

The RAS–ERK pathway is known to play a pivotal role in differentiation, proliferation and tumour progression. Here, we show that Erk downregulates Forkhead box O 3a (FOXO3a) by directly interacting with and phosphorylating FOXO3a at Ser 294, Ser 344 and Ser 425, which consequently promotes cell proliferation and tumorigenesis. The ERK-phosphorylated FOXO3a degrades via an MDM2-mediated ubiquitin-proteasome pathway. However, the non-phosphorylated FOXO3a mutant is resistant to the interaction and degradation by murine double minute 2 (MDM2), thereby resulting in a strong inhibition of cell proliferation and tumorigenicity. Taken together, our study elucidates a novel pathway in cell growth and tumorigenesis through negative regulation of FOXO3a by RAS–ERK and MDM2.

Predominant Th2/Tc2 Polarity of Tumor-Infiltrating Lymphocytes in Human Cervical Cancer

Cytotoxic T lymphocytes (Tc) play a central role in cellular immunity against cancers. The cytotoxic potential of freshly isolated tumor-infiltrating lymphocytes (TILs) is usually not expressed. This suggests the possible existence of as yet unspecified and perhaps complex immunosuppressive factors or cytokines that affect the anti-tumor capacity of these TILs in the tumor milieu. In the present study, we demonstrated for the first time that TILs derived from human cervical cancer tissue consist mainly of Th2/Tc2 phenotypes. In vitro kinetic assays further revealed that cancer cells could direct the tumor-encountered T cells toward the Th2/Tc2 polarity. Cancer cells promote the production of IL-4 and down-regulate the production of IFN-γ in cancer-encountered T cells. The regulatory effects of cervical cancer cells are mediated mainly by IL-10, and TGF-β plays only a synergistic role. The cancer-derived effects can be reversed by neutralizing anti-IL-10 and anti-TGF-β Abs. IL-10 and TGF-β are present in cancer tissue and weakly expressed in precancerous tissue, but not in normal cervical epithelial cells. Our study strongly suggests important regulatory roles of IL-10 and TGF-β in cancer-mediated immunosuppression.

Molecular signatures of metaplastic carcinoma of the breast by large-scale transcriptional profiling: identification of genes potentially related to epithelial-mesenchymal transition.

Metaplastic carcinoma of the breast (MCB) is a poorly understood subtype of breast cancer. It is generally characterized by the coexistence of ductal carcinomatous and transdifferentiated sarcomatous components, but the underlying molecular alterations, possibly related to epithelial–mesenchymal transition (EMT), remain elusive. We performed transcriptional profiling using half-a-genome oligonucleotide microarrays to elucidate genetic profiles of MCBs and their differences to those of ductal carcinoma of breasts (DCBs) using discarded specimens of four MCBs and 34 DCBs. Unsupervised clustering disclosed distinctive expression profiles between MCBs and DCBs. Supervised analysis identified gene signatures discriminating MCBs from DCBs and between MCB subclasses. Notably, many of the discriminator genes were associated with downregulation of epithelial phenotypes and with synthesis, remodeling and adhesion of extracellular matrix, with some of them have known or inferred roles related to EMT. Importantly, several of the discriminator genes were upregulated in a mutant Snail-transfected MCF7 cell known to exhibit features of EMT, thereby indicating a crucial role for EMT in the pathogenesis of MCBs. Finally, the identification of SPARC and vimentin as poor prognostic factors reinforced the role of EMT in cancer progression. These data advance our understanding of MCB and offer clues to the molecular alterations underlying EMT.

p53 overexpression and mutation in metaplastic carcinoma of the breast: genetic evidence for a monoclonal origin of both the carcinomatous and the heterogeneous sarcomatous components

Metaplastic carcinoma of the breast (MCB) is characterized by the biphasic presence of both a carcinomatous component (CC) and heterogeneous sarcomatous components (HSCs). Although an epithelial or myoepithelial origin of the HSCs has been suggested, molecular evidence for a common origin for the CC and HSCs is limited and the mechanism underlying the sarcomatous or metaplastic change is unknown. The present study investigated the frequency and nature of p53 expression and mutation in 11 biphasic and three monophasic MCBs by immunohistochemistry and either needle‐assisted or laser‐capture microdissection, followed by PCR and direct sequencing. In all 11 biphasic MBCs, staining for p53 was concordant in the CC and HSCs (8/11 positive and 3/11 negative), consistent with a monoclonal origin of both components. Significantly, whenever a component of carcinoma in situ was present (5/11), the p53 staining was always concordant with that in the CC and HSCs. Screening of the 14 cases for p53 mutation identified four mutants, each in a single case of biphasic MCB with concordant p53 overexpression. Both the CC and each of the HSCs revealed identical p53 mutation in all four cases; in addition, one of the four cases also had an in situ component and the same mutant was found simultaneously in the in situ, invasive, and sarcomatous components. The concordant pattern of p53 alteration (overexpression or mutation) implies that early p53 mutation, occurring prior to invasion, was maintained throughout tumour progression and metaplastic change. The findings therefore support a monoclonal histogenesis of the various components, but are neutral regarding the role of p53 alteration in the development of metaplastic change in MCBs. Copyright

Merkel cell carcinoma and chronic arsenicism

Arsenic is a well-documented human carcinogen. Bowens disease, squamous cell carcinoma, and basal cell carcinoma are the most common skin cancers found in patients exposed to arsenic over the long term. Merkel cell carcinoma has been documented in Taiwanese patients who resided in an endemic area of black foot disease, another condition found in patients with chronic arsenicism. We collected all cases of Merkel cell carcinoma diagnosed at two medical centers in Taiwan (N = 11) to find a possible association between chronic arsenicism and Merkel cell carcinoma. In our study 6 of the 11 patients were residents of the endemic areas for chronic arsenicism.

Nuclear ErbB2 enhances translation and cell growth by activating transcription of ribosomal RNA genes

Aberrant regulation of rRNA synthesis and translation control can facilitate tumorigenesis. The ErbB2 growth factor receptor is overexpressed in many human tumors and has been detected in the nucleus, but the role of nuclear ErbB2 is obscure. In this study, we defined a novel function of nuclear ErbB2 in enhancing rRNA gene transcription by RNA polymerase-I (RNA Pol I). Nuclear ErbB2 physically associates with β-actin and RNA Pol I, coinciding with active RNA Pol I transcription sites in nucleoli. RNA interference-mediated knockdown of ErbB2 reduced pre-rRNA and protein synthesis. In contrast, wild-type ErbB2 augmented pre-rRNA level, protein production, and cell size/cell growth, but not by an ErbB2 mutant that is defective in nuclear translocation. Chromatin immunoprecipitation assays revealed that ErbB2 enhances binding of RNA Pol I to rDNA. In addition, ErbB2 associated with rDNA, RNA Pol I, and β-actin, suggesting how it could stimulate rRNA production, protein synthesis, and increased cell size and cell growth. Finally, ErbB2-potentiated RNA Pol I transcription could be stimulated by ligand and was not substantially repressed by inhibition of PI3-K and MEK/ERK (extracellular signal regulated kinase), the main ErbB2 effector signaling pathways. Together, our findings indicate that nuclear ErbB2 functions as a regulator of rRNA synthesis and cellular translation, which may contribute to tumor development and progression.

The Interactions Between GPR30 and the Major Biomarkers in Infiltrating Ductal Carcinoma of the Breast in an Asian Population

OBJECTIVE G-protein-coupled receptor 30 (GPR30) has been reported to be a novel estrogen receptor alpha (ERalpha) in vitro. Therefore, the interactions among GPR30, ERalpha, progesterone receptor (PR) and human epidermal growth factor receptor-2 (HER-2/neu), and their prognostic utilities in the infiltrating ductal carcinoma (IDC) of the breast were evaluated. MATERIALS AND METHODS Messenger RNA (mRNA) levels of GPR30, ERalpha, PR and HER-2/neu in the tumor samples of 118 Taiwanese IDC patients and 27 non-tumor mammary tissues were measured via quantitative polymerase chain reaction analyses. The correlations of GPR30 mRNA levels with clinical parameters, i.e. tumor/non-tumor, ERalpha, PR, HER-2/neu, age, lymph node metastasis, lymph-vascular invasion, grade, stage and patient survival, were assessed by using appropriate statistical analyses. RESULTS GPR30 expression was observed to be lower in IDC (p < 0.001) than in non-tumor mammary tissues. Importantly, GPR30 mRNA level was positively correlated with that of ERalpha (p = 0.001) and PR (p = 0.001) but not correlated with that of HER-2/neu when they were analyzed as continuous variables. However, lower GPR30 was noticed in tumors with HER-2/neu protein overexpression. GPR30 expression was not correlated with age, lymph node metastasis, lymph-vascular invasion, grade and stage in IDC. GPR30 expression was not an independent prognostic factor for patient survival. CONCLUSION GPR30 expression is downregulated in IDC. GPR30 is preferentially co-expressed with ER and/or PR but is lowly expressed in HER-2/neu(+) tumors. The correlation of GPR30 expression with clinical parameters, including patient survival, was not evident in this cohort.

Differential expression of glucocorticoid receptor in human breast tissues and related neoplasms.

Glucocorticoid receptor (GR) is a steroid hormone receptor that has been shown to play important roles in mammary development and differentiation, and has been implicated in breast tumourigenesis, but its precise biological significance in mammary pathophysiology remains unclear. In order to generate a comprehensive expression profile for GR in normal versus neoplastic breast tissues, GR expression was investigated in situ in 400 human breast tissue samples, comprising normal tissue and a range of benign, pre‐invasive, and invasive lesions, using immunohistochemical assays. The novel expression of GR in myoepithelium, not observed in luminal epithelium, not only demonstrates expression patterns exclusive to the alpha form of oestrogen receptor and progesterone receptor and suggests distinctive functions between GR and these two important steroid hormone receptors in the breast, but may also indicate unique physiological and perhaps pathological roles for the myoepithelium in mediating the effects of glucocorticoid hormones in the breast. The strong expression of GR in metaplastic carcinomas (94.4%) and malignant phyllodes tumours (92.3%) suggests a pathogenetic role for GR, and implies that targeting GR in these tumours may have potential therapeutic application. However, studies on the roles of GR in mammary carcinogenesis should be interpreted with great caution, based on the lack of GR expression in cancer cells in the great majority (98.2%) of non‐metaplastic carcinomas, which has gone unnoticed in previous studies. This marked discrepancy warrants a re‐examination of the biological roles of GR in the pathophysiology of breast malignancy. The lack of methylation in the promoter region of the GR gene in all 118 non‐metaplastic carcinomas, as demonstrated by methylation‐specific PCR and bisulphite DNA sequencing analysis, indicates that methylation is less likely to play a role in the reduction of GR expression in non‐metaplastic carcinoma of the breast. Copyright

Coexisting Sclerosing Angiomatoid Nodular Transformation of the Spleen with Multiple Calcifying Fibrous Pseudotumors in a Patient

Primary tumor or tumor-like lesions of the spleen are rare. Among them, vascular lesions are the most common. Vascular tumor of the spleen is different from the usual hemangioma of soft tissue because the vascular structure of the spleen is unique. Sclerosing angiomatoid nodular transformation (SANT) is a recently described vascular lesion of the spleen. Grossly, it is a multinodular, well-circumscribed tumor containing a hypervascular core. Microscopically, it comprises three types of vessels, and each type recapitulates the immunohistochemical characteristics of the normal vascular elements of the splenic red pulp, i.e. capillaries, sinusoids, and small veins, respectively. Because of the rarity of this entity, its actual pathogenesis is still unknown. In this study, we report a case of SANT occurring in a 43-year-old woman, in whom there were also multiple calcifying fibrous pseudotumors (CFPTs) in the abdominal cavity. Both SANT and CFPT are thought to be variants of inflammatory pseudotumor. Coexistence of these two rare entities in a patient has never been reported, and this fact suggests that there might be a common mechanism contributing to the formation of these two types of lesions.

Expression of Cyclin-Dependent Kinase 6 (cdk6) and Frequent Loss of CD44 in Nasal-Nasopharyngeal NK/T-Cell Lymphomas: Comparison with CD56-Negative Peripheral T-Cell Lymphomas

Lymphomas involving the nasal and nasopharyngeal region mainly include CD56-positive natural killer (NK)/T-cell lymphomas, CD56-negative peripheral T-cell lymphomas (PTL), and B-cell lymphomas. Among these, the CD56-positive lymphoma, presumably of an NK/T-cell nature, is frequently seen in Asian, Mexican, and South American patients. NK cells are proposed to be closer developmentally to T cells than to other lymphoid cells, because bipotential common progenitor cells of NK/T-cell lineage have been isolated. In this study, we collected 47 cases of nasal lymphoma and investigated the phenotypic difference between NK/T-cell lymphoma and PTL by examining the pattern of the developmentally differentially expressed molecules cdk6 (cyclin-dependent kinase 6), CD44, CD117, and by examining the rearrangement of the T-cell receptor gene (TcR-GR). cdk6, an essential regulator of the cell cycle in G1 progression, was over-expressed in a subset of cortical thymocytes, but absent in mature thymocytes. In contrast, CD44, a glycosylated adhesion molecule, was absent in cortical thymocytes, but present in mature thymocytes and peripheral activated T cells. We found both over-expression of nuclear cdk6 (n-cdk6) and frequent absence of CD44 in nasal CD56-positive NK/T-cell lymphomas, in contrast to most nasal CD56-negative PTL, which were CD44-immunoreactive with weak or no expression of n-cdk6. Almost all tested cases of NK/T-cell lymphoma displayed a germ-line configuration of TcR, without evidence of gene rearrangement. Thus, there seems to be a useful distinction between the classical NK/T type of nasal lymphoma (CD56+/n-cdk6+/CD44−/TcR-GR−) and PTL (CD56−/n-cdk6−/CD44+/TcR-GR+) involving the nasal region. The presence of Epstein-Barr virus does not seem to be a good marker for distinguishing between NK/T lymphoma and PTL involving the nasal region.