Changes of apoptosis, p53, and bcl-2 by irradiation in poorly differentiated thyroid carcinoma cell lines: a prognostic marker for the prospect of therapeutic success?

The p53 Protein Family in the Response of Tumor Cells to Ionizing Radiation: Problem Development

Survival mechanisms are activated in tumor cells in response to therapeutic ionizing radiation. This reduces a treatment's effectiveness. The p53, p63, and p73 proteins belonging to the family of proteins that regulate the numerous pathways of intracellular signal transduction play a key role in the development of radioresistance. This review analyzes the p53-dependent and p53-independent mechanisms involved in overcoming the resistance of tumor cells to radiation exposure.

Preparation of A Spaceflight: Apoptosis Search in Sutured Wound Healing Models

To prepare the ESA (European Space Agency) spaceflight project “Wound healing and Sutures in Unloading Conditions”, we studied mechanisms of apoptosis in wound healing models based on ex vivo skin tissue cultures, kept for 10 days alive in serum-free DMEM/F12 medium supplemented with bovine serum albumin, hydrocortisone, insulin, ascorbic acid and antibiotics at 32 °C. The overall goal is to test: (i) the viability of tissue specimens; (ii) the gene expression of activators and inhibitors of apoptosis and extracellular matrix components in wound and suture models; and (iii) to design analytical protocols for future tissue specimens after post-spaceflight download. Hematoxylin-Eosin and Elastica-van-Gieson staining showed a normal skin histology with no signs of necrosis in controls and showed a normal wound suture. TdT-mediated dUTP-biotin nick end labeling for detecting DNA fragmentation revealed no significant apoptosis. No activation of caspase-3 protein was detectable. FASL, FADD, CASP3, CASP8, CASP10, BAX, BCL2, CYC1, APAF1, LAMA3 and SPP1 mRNAs were not altered in epidermis and dermis samples with and without a wound compared to 0 day samples (specimens investigated directly post-surgery). BIRC5, CASP9, and FN1 mRNAs were downregulated in epidermis/dermis samples with and/or without a wound compared to 0 day samples. BIRC2, BIRC3 were upregulated in 10 day wound samples compared to 0 day samples in epidermis/dermis. RELA/FAS mRNAs were elevated in 10 day wound and no wound samples compared to 0 day samples in dermis. In conclusion, we demonstrate that it is possible to maintain live skin tissue cultures for 10 days. The viability analysis showed no significant signs of cell death in wound and suture models. The gene expression analysis demonstrated the interplay of activators and inhibitors of apoptosis and extracellular matrix components, thereby describing important features in ex vivo sutured wound healing models. Collectively, the performed methods defining analytical protocols proved to be applicable for post-flight analyzes of tissue specimens after sample return.

MHC class I loss is a frequent mechanism of immune escape in papillary thyroid cancer that is reversed by interferon and selumetinib treatment in vitro

PURPOSE

To evaluate MHC class I expression on papillary thyroid cancer (PTC) and analyze changes in MHC expression and associated immune activation with current and experimental treatments for thyroid cancer using in vitro PTC cell lines.

EXPERIMENTAL DESIGN

MHC class I expression and assessment of tumor-infiltrating leukocyte populations were evaluated by immunohistochemistry. PTC cell lines were analyzed for HLA-ABC expression by flow cytometry following tyrosine kinase inhibitor, IFNα or IFNγ, or radiation treatment. Functional changes in antigenicity were assessed by coculture of allogeneic donor peripheral blood leukocytes (PBL) with pretreated or untreated PTC cell lines and measurement of T-cell activation and cytokine production.

RESULTS

Both MHC class I and β2-microglobulin expression was reduced or absent in 76% of PTC specimens and was associated with reduced tumor-infiltrating immune cells, including effector (CD3(+), CD8(+), CD16(+)) and suppressor (FoxP3(+)) populations. Treatment of PTC cell lines with the MEK1/2 inhibitor selumetinib or IFN increased HLA-ABC expression. This phenotypic change was associated with increased T-cell activation (%CD25(+) of CD3(+)) and IL2 production by PBL cocultured with treated PTC cell lines. Additive effects were seen with combination selumetinib and IFN treatment.

CONCLUSIONS

MHC class I expression loss is frequent in human PTC specimens and represents a significant mechanism of immune escape. Increased antigenicity following selumetinib and IFN treatment warrants further study for immunotherapy of progressive PTC.

Mechanisms of apoptosis in irradiated and sunitinib-treated follicular thyroid cancer cells

The multikinase inhibitor sunitinib (S) seems to have promising potential in the treatment of thyroid cancer. We focused on the impact of S and/or irradiation (R) on mechanisms of apoptosis in follicular thyroid cancer cells. The effects of R, S and their combination were evaluated 2 and 4 days after treatment, using the human thyroid cancer cell line CGTH W-1. The transcription of genes involved in the regulation of apoptosis was investigated using quantitative real-time PCR. Western blot analyses of caspases and survivin were also performed. S elevated BAX (day 4), CASP9, CASP3, BIRC5 (day 4) and PRKACA (day 4) gene expression, whereas the mRNAs of BCL2, CASP8, PRKCA, ERK1, and ERK2 were not significantly changed. S, R and R+S clearly induced caspase-9 protein and elevated caspase-3 activity. Survivin was down-regulated at day 4 in control cells and the expression was blunted by S treatment. R+S induced survivin expression at day 2 followed by a reduction at day 4 of treatment. Sunitinib and the combined application with radiation induced apoptosis in follicular thyroid cancer cells via the intrinsic pathway of apoptosis. In addition, sunitinib might induce apoptosis via decreased expression of the anti-apoptotic protein survivin. These findings suggest the potential use of sunitinib for the treatment of poorly differentiated follicular thyroid carcinomas.

Function of carbonic anhydrase IX in glioblastoma multiforme

Carbonic anhydrase (CA) IX is over-expressed in glioblastoma; however, its functions in this context are unknown. Metabolically, glioblastomas are highly glycolytic, leading to a significant lactic acid load. Paradoxically, the intracellular pH is alkaline. We hypothesized that CAIX contributes to the extrusion of hydrogen ions into the extracellular space, thereby moderating intra- and extracellular pH and creating an environment conductive to enhanced invasion. We investigated the role of CAIX as a prognostic marker in patients with glioblastoma and its biological function in vitro. CAIX expression was analyzed in 59 patients with glioblastoma by immunohistochemistry. The expression levels were correlated to overall survival. In vitro, U251 and Ln 18 glioblastoma cells were incubated under hypoxia to induce CAIX expression, and RNA interference (RNAi) was used to examine the function of CAIX on cell attachment, invasion, intracellular energy transfer, and susceptibility to adjuvant treatment. High CAIX expression was identified as an independent factor for poor survival in patients with glioblastoma. In vitro, cell attachment and invasion were strongly reduced after knockdown of CAIX. Finally, the effects of radiation and chemotherapy were strongly augmented after CAIX interference and were accompanied by a higher rate of apoptotic cell death. CAIX is an independent prognostic factor for poor outcome in patients with glioblastoma. Cell attachment, invasion, and survival during adjuvant treatment are significantly influenced by high CAIX expression. These results indicate that inhibition of CAIX is a potential metabolic target for the treatment of patients with glioblastoma.

How and why does the proteome respond to microgravity?

For medical and biotechnological reasons, it is important to study mammalian cells, animals, bacteria and plants exposed to simulated and real microgravity. It is necessary to detect the cellular changes that cause the medical problems often observed in astronauts, cosmonauts or animals returning from prolonged space missions. In order for in vitro tissue engineering under microgravity conditions to succeed, the features of the cell that change need to be known. In this article, we summarize current knowledge about the effects of microgravity on the proteome in different cell types. Many studies suggest that the effects of microgravity on major cell functions depend on the responding cell type. Here, we discuss and speculate how and why the proteome responds to microgravity, focusing on proteomic discoveries and their future potential.