9 research outputs found
MicroRNA-21 links epithelial-to-mesenchymal transition and inflammatory signals to confer resistance to neoadjuvant trastuzumab and chemotherapy in HER2-positive breast cancer patients
Patients with primary HER2-positive breast cancer benefit from HER2-targeted therapies. Nevertheless, a significant proportion of these patients die of disease progression due to mechanisms of drug resistance. MicroRNAs (miRNAs) are emerging as critical core regulators of drug resistance that act by modulating the epithelial- to-mesenchymal transition (EMT) and cancer-related immune responses. In this study, we investigated the association between the expression of a specific subset of 14 miRNAs involved in EMT processes and immune functions and the response to neoadjuvant trastuzumab and chemotherapy in 52 patients with HER2-overexpressing breast tumors. The expression of only a single miRNA, miR-21, was significantly associated with residual disease (p = 0.030) and increased after trastuzumab-chemotherapy (p = 0.012). A target prediction analysis coupled with in vitro and in vivo validations revealed that miR-21 levels inversely correlated with the expression of PTEN (rs = -0.502; p = 0.005) and PDCD4 (rs = -0.426; p = 0.019), which differentially influenced the drug sensitivity of HER2-positive breast cancer cells. However, PTEN expression was only marginally associated with residual disease. We further demonstrated that miR-21 was able to affect the response to both trastuzumab and chemotherapy, triggering an IL-6/STAT3/NF-\u3baB-mediated signaling loop and activating the PI3K pathway. Our findings support the ability of miR-21 signaling to sustain EMT and shape the tumor immune microenvironment in HER2-positive breast cancer. Collectively, these data provide a rationale for using miR-21 expression as a biomarker to select trastuzumab-chemotherapy-resistant HER2-positive breast cancer patients who may benefit from treatments containing PI3K inhibitors or immunomodulatory drugs
Complex engagement of DNA-damage response pathways in human cancer and in lung tumor progression
Tumor initiation and progression provide a multitude of occasions for the generation of DNA damage and the consequent activation of the DNA damage response (DDR) pathway. DDR signaling involves the engagement of key factors such as ATM, CHK2, 53BP1 and the phosphorylation of histone H2AX (gamma-H2AX). The systematic study of DDR in human tumors and normal tissues by high-throughput tissue microarrays revealed that ATM and gamma-H2AX were engaged in cancer but the extent of their activation was strongly affected by the organ and cell type involved, whereas 53BP1 loss was the most consistent feature among the tumor studied. Unexpectedly, we also observed activated DDR markers in morphologically normal tissues, also in association with inflammation. Analysis of the dynamic engagement of DDR along the different stages of lung tumorigenesis showed that 53BP1 loss occurs early at the transition from normal to dysplastic change whereas the activated forms of ATM and CHK2, but not gamma-H2AX, initially accumulate in pre-invasive lesions and are then lost during tumor progression. In individual lung tumors, the activation of ATM, CHK2 and the presence of 53BP1 were consistently correlated, whereas gamma-H2AX did not correlate with activated ATM. Finally, the study of associations between critical clinicopathological parameters and activated DDR factors highlighted a statistically meaningful correlation between reduced local tumor extension and the phosphorylation of ATM, CHK2 and the presence of 53BP1, whereas no significant correlations with parameters such as survival or relapse of early-stage lung carcinomas were found
Malakoplakia of the pancreas with diffuse lymph-node involvement
We report a case of malakoplakia involving the pancreas in a 74-year-old man with associated regional lymphoadenopathy. Histological examination of both pancreas and lymph nodes revealed a diffuse histiocytic infiltrate containing numerous Michaelis-Gutmann bodies. Electron microscopy supported the diagnosis of malakoplakia and showed bacterial-like structures. Differential diagnosis includes myofibroblastic inflammatory tumor and histiocytic neoplasms. Lymph-node involvement during malakoplakia is extremely rare and it has never been documented microscopically. Lymphohematogenous spread of bacteria may be the cause of the nodal involvement, which, however, does not appear to influence the clinical course of the disease
Molecular and immunohistochemical analysis of HER2/neu oncogene in synovial sarcoma
Amplification and/or overexpression of HER2/neu have been documented in many types of epithelial tumor and recently has been reported in sarcomas, particularly in osteosarcomas. But the role of HER2/neu alterations in soft tissue tumors remains poorly understood. Thus the present study investigates the expression of HER2/ neu in 13 patients with synovial sarcoma (SS). In this study, HER2/ neu mRNA levels were measured in frozen tissue samples using a real-time reverse transcription-polymerase chain reaction assay; protein expression was assessed by immunohistochemistry using an anti-HER2/neu polyclonal antibody. Six normal skeletal muscle specimens were used to establish basal levels of HER2/neu mRNA. HER2/neu transcripts were detected in all normal tissues and SSs. Four of 13 sarcomas (31%) demonstrated HER2/neu mRNA levels above the mean value, whereas 3 tumors (23%) displayed HER2/neu protein overexpression. Both membranous and cytoplasmic patterns of immunostaining were observed, and a strong correlation was found between protein expression and mRNA level (P = 0.01). Increased HER2/neu mRNA levels were significantly associated with a lower risk of developing recurrences (P = 0.02). Moreover, none of the patients with HER2/neu overexpression developed metastasis. Our data demonstrate that HER2/neu is expressed in SSs and that both membrane and cytoplasmic HER2/neu expression correlate with mRNA levels. Our results show that the presence of increased levels of HER2/neu in SSs is associated with a more favorable clinical course. Further studies are needed to assess the role of this oncogene in SSs and to evaluate the application of inhibitory humanized monoclonal antibodies in the treatment regimens for this malignancy
Oncogene-induced senescence is a DNA damage response triggered by DNA hyper-replication
Early tumorigenesis is associated with the engagement of the DNA-damage checkpoint response (DDR). Cell proliferation and transformation induced by oncogene activation are restrained by cellular senescence. It is unclear whether DDR activation and oncogene-induced senescence (OIS) are causally linked. Here we show that senescence, triggered by the expression of an activated oncogene (H-RasV12) in normal human cells, is a consequence of the activation of a robust DDR. Experimental inactivation of DDR abrogates OIS and promotes cell transformation. DDR and OIS are established after a hyper-replicative phase occurring immediately after oncogene expression. Senescent cells arrest with partly replicated DNA and with DNA replication origins having fired multiple times. In vivo DNA labelling and molecular DNA combing reveal that oncogene activation leads to augmented numbers of active replicons and to alterations in DNA replication fork progression. We also show that oncogene expression does not trigger a DDR in the absence of DNA replication. Last, we show that oncogene activation is associated with DDR activation in a mouse model in vivo. We propose that OIS results from the enforcement of a DDR triggered by oncogene-induced DNA hyper-replication
The differential role of L1 in ovarian carcinoma and normal ovarian surface epithelium
Epithelial ovarian carcinoma (EOC) arises from the ovarian surface epithelium (OSE), a monolayer of poorly differentiated epithelial cells that lines the ovary. The molecular mechanisms underlying EOC invasion into the surrounding stroma and dissemination to the peritoneum and to retroperitoneal lymph nodes are still unclear. Here, we analyzed the expression and the functional role of the cell adhesion molecule L1 during EOC development. In patient-derived samples, L1 was expressed both in OSE and in a subset of EOC, in the latter being mostly restricted to the invasive areas of the tumors. The expression of L1 correlated significantly with poor outcome and with unfavorable clinicopathologic features of the disease. The peculiar expression pattern of L1 in normal OSE and invasive EOC raised the possibility that this adhesion molecule serves a different function in nontransformed versus neoplastic ovarian epithelial cells. Indeed, we showed that in OSE cells L1 supports cell-cell adhesion and enhances apoptosis, whereas it has no effect on cell proliferation and invasion. In contrast, L1 inhibits cell-cell adhesion and apoptosis in ovarian carcinoma cells, where it promotes malignancy-related properties, such as cell proliferation, Erk1/2-dependent and phosphoinositide 3-kinase-dependent invasion, and transendothelial migration. Interestingly, a crosstalk with the fibroblast growth factor receptor signaling is implicated in the promalignant function of L1 in tumor cells. Our findings point to L1 as an EOC biomarker correlating with poor prognosis, and highlight a switch in L1 function associated to the neoplastic transformation of ovarian epithelial cells, thus implicating L1 as a potential therapeutic targe
8p11 myeloproliferative syndrome with a novel t(7;8) translocation leading to fusion of the FGFR1 and TIF1 genes
8p11 myeloproliferative syndrome (EMS) is a clinical-pathologic entity characterized by rearrangements involving the FGFR1 gene, which encodes a receptor tyrosine kinase. These rearrangements invariably lead to aberrant fusion proteins in which the kinase activity is constitutively turned on, with resulting oncogenic properties. In this article, we describe a new translocation in EMS, t(7;8)(q34;p11), in which the FGFR1 gene is fused to a previously unidentified partner, the TIF1 gene. We show that both the TIF1-FGFR1 and FGFR1-TIF1 fusion proteins have the potential to be translated as a result of the translocation. Thus, our data extend the involvement of FGFR1 in EMS and lend support to the concept that there is a precise correlation between genotype and phenotype in this diseas
Stem cells and tissue engineering techniques.
The therapeutic use of stem cells and tissue engineering techniques are emerging in urology. Here, stem cell types, their differentiating potential and fundamental characteristics are illustrated. The cancer stem cell hypothesis is reported with reference to the role played by stem cells in the origin, development and progression of neoplastic lesions. In addition, recent reports of results obtained with stem cells alone or seeded in scaffolds to overcome problems of damaged urinary tract tissue are summarized. Among others, the application of these biotechnologies in urinary bladder, and urethra are delineated. Nevertheless, apart from the ethical concerns raised from the use of embryonic stem cells, a lot of questions need to be solved concerning the biology of stem cells before their widespread use in clinical trials. Further investigation is also required in tissue engineering utilizing animal models