Purpose: The aim of this study was to assess the activity of hedgehog signaling pathway in malignant pleural mesothelioma (MPM).Experimental Design: The expression of hedgehog signaling components was assessed by quantitative PCR and in situ hybridization in 45 clinical samples. Primary MPM cultures were developed in serum-free condition in 3% oxygen and were used to investigate the effects of smoothened (SMO) inhibitors or GLI1 silencing on cell growth and hedgehog signaling. In vivo effects of SMO antagonists were determined in an MPM xenograft growing in nude mice.Results: A significant increase in GLI1, sonic hedgehog, and human hedgehog interacting protein gene expression was observed in MPM tumors compared with nontumoral pleural tissue. SMO antagonists inhibited GLI1 expression and cell growth in sensitive primary cultures. This effect was mimicked by GLI1 silencing. Reduced survivin and YAP protein levels were also observed. Survivin protein levels were rescued by overexpression of GLI1 or constitutively active YAP1. Treatment of tumor-bearing mice with the SMO inhibitor HhAntag led to a significant inhibition of tumor growth in vivo accompanied by decreased Ki-67 and nuclear YAP immunostaining and a significant difference in selected gene expression profile in tumors.Conclusions: An aberrant hedgehog signaling is present in MPM, and inhibition of hedgehog signaling decreases tumor growth indicating potential new therapeutic approach.

To determine whether metastasis to brain is associated with altered expression patterns of integrins, we investigated the expression of avb3, avb5, avb6 and avb8 integrins in primary malignancies and metastases to brain of breast, lung and renal carcinomas and in malignant melanoma. Inhibitors of av integrins are currently in clinical trials for glioblastoma. The role of integrins in the process of brain metastasis from other human tumors is unknown. Immunohistochemistry with novel integrin subtype specific rabbit monoclonal antibodies was performed on tissue microarrays of archival material of surgical biopsies taken from primary tumors and brain metastases. Integrin avb3 expression was increased in brain metastases compared to primary tumors of breast adenocarcinoma, non-small cell lung cancer, renal clear cell cancer and malignant cutaneous melanoma (all p < 0.01). Similarly, integrin avb8 expression was increased in brain metastases compared to primary tumors of breast cancer (p < 0.0001), lung cancer (p < 0.01) and renal cancer (p < 0.0001), with a similar trend in metastatic melanoma. Integrin avb5 was expressed in most primary tumors (98% breast cancer; 67% lung cancer; 90% renal cancer; 89% melanoma) and showed a stronger expression in brain metastases compared to primary tumors from lung cancer and melanoma (p < 0.05). Also integrin avb6 expression was increased in brain metastases compared to primary breast cancer (p < 0.001). Conclusions: The stronger av-integrin expression in brain metastases, especially of avb3 and avb8 integrins, suggests that certain av integrin are involved in the process of brain metastasis. av Integrins may be therapeutic targets for patients with metastatic cancer in brain.Some 45% of cancer patients develop brain metastases during the course of their illness, with 98,000 to 170,000 new cases diagnosed each year in the U.S. alone. 1 There is an increasing prevalence of brain metastases, as primary treatments have become more effective, and people with cancer live longer after initial treatment. Changes in cellular protein levels accompany the metastatic processes, but the molecular details and drivers of the process are unknown for most cancers. These changes allow tumor cells to escape the primary, and to attach and survive at foreign sites, 2,3 which strongly implicates a role for an altered activity of integrins during tumor progression. Integrins are a family of heterodimeric transmembrane glycoproteins that classically bind the extracellular matrix (ECM) to influence cell attachment, motility, cell proliferation, invasion and tumor cell metastasis. 4,5 Several integrin-dependent mechanisms may influence metastasis. Integrins influence tumor cell survival 6 and migration and invasive processes, 7 thereby affecting tumor growth and metastasis. 8 Different integrins in different cellular contexts can either enhance survival or initiate apoptosis. 6,9,10 Although integrins cannot transform cells, several cooperate with oncogenes or receptor tyrosine kinases 6 to influence tum...

Multimodal therapy concepts have been successfully implemented in the treatment of locally advanced gastrointestinal malignancies. The effects of neoadjuvant chemo- or radiochemotherapy such as scarry fibrosis or resorptive changes and inflammation can be determined by histopathological investigation of the subsequent resection specimen. Tumor regression grading (TRG) systems which aim to categorize the amount of regressive changes after cytotoxic treatment mostly refer onto the amount of therapy induced fibrosis in relation to residual tumor or the estimated percentage of residual tumor in relation to the previous tumor site. Commonly used TRGs for upper gastrointestinal carcinomas are the Mandard grading and the Becker grading system, e.g., and for rectal cancer the Dworak or the Rödel grading system, or other systems which follow similar definitions. Namely for gastro-esophageal carcinomas these TRGs provide important prognostic information since complete or subtotal tumor regression has shown to be associated with better patient’s outcome. The prognostic value of TRG may even exceed those of currently used staging systems (e.g., TNM staging) for tumors treated by neoadjuvant therapy. There have been some limitations described regarding interobserver variability especially in borderline cases, which may be improved by standardization of work up of resection specimen and better training of histopathologic determination of regressive changes. It is highly recommended that TRG should be implemented in every histopathological report of neoadjuvant treated gastrointestinal carcinomas. The aim of this review is to disclose the relevance of histomorphological TRG to accomplish an optimal therapy for patients with gastrointestinal carcinomas.

Transforming growth factor-β is a central mediator of the malignant phenotype of glioblastoma, the most common and malignant form of intrinsic brain tumours. Transforming growth factor-β promotes invasiveness and angiogenesis, maintains cancer cell stemness and induces profound immunosuppression in the host. Integrins regulate cellular adhesion and transmit signals important for cell survival, proliferation, differentiation and motility, and may be involved in the activation of transforming growth factor-β. We report that αvβ3, αvβ5 and αvβ8 integrins are broadly expressed not only in glioblastoma blood vessels but also in tumour cells. Exposure to αv, β3 or β5 neutralizing antibodies, RNA interference-mediated integrin gene silencing or pharmacological integrin inhibition using the cyclic RGD peptide EMD 121974 (cilengitide) results in reduced phosphorylation of Smad2 in most glioma cell lines, including glioma-initiating cell lines and reduced transforming growth factor-β-mediated reporter gene activity, coinciding with reduced transforming growth factor-β protein levels in the supernatant. Time course experiments indicated that the loss of transforming growth factor-β bioactivity due to integrin inhibition likely results from two distinct mechanisms: an early effect on activation of preformed inactive protein, and second, major effect on transforming growth factor-β gene transcription as confirmed by decreased activity of the transforming growth factor-β gene promoter and decreased transforming growth factor-β(1) and transforming growth factor-β(2) messenger RNA expression levels. In vivo, EMD 121974 (cilengitide), which is currently in late clinical development as an antiangiogenic agent in newly diagnosed glioblastoma, was a weak antagonist of pSmad2 phosphorylation. These results validate integrin inhibition as a promising strategy not only to inhibit angiogenesis, but also to block transforming growth factor-β-controlled features of malignancy including invasiveness, stemness and immunosuppression in human glioblastoma.

Activation of periostin-triggered EMT is associated with the sarcomatoid histotype and has an impact on shorter survival of MPM patients. Finally, only the high expression of PTEN and the low expression of cytosolic periostin could be shown to be independent prognostic factors for longer OS.