Evaluation of Combined CK2 Inhibition and Irradiation in Human WiDr Tumours.

Background/aim: Casein kinase 2 (CK2) which sustains multiple pro-survival functions in cellular DNA-damage response, is strictly regulated in normal cells but elevated in cancer. CK2 is considered as a potential therapeutic target, and its inhibition has been associated with radiosensitization in mammalian cells in vitro. Here, we investigated potential radiosensitization by CK2 inhibition in vivo.

Impact of dimethyl sulfoxide on irradiation-related DNA double-strand-break induction, -repair and cell survival.

Dimethyl sulfoxide (DMSO) is an effective radical scavenger and, when added to cells, reduces the initial number of radiation-induced DNA double-strand breaks (DSB). The aim of this study was to investigate modification by DMSO of both DSB induction and DSB repair by means of pulsed-field gel electrophoresis (PFGE) as well as gamma-H2AX immunofluorescence staining. WiDr cells (human colon carcinoma provided by DKFZ) were incubated with 2% DMSO for 2 h (or mock-treated) prior to irradiation with varying X-ray doses and subsequent incubation for repair.

DNA damage response of clinical carbon ion versus photon radiation in human glioblastoma cells.

Background And Purpose: Carbon ion radiotherapy is a promising therapeutic option for glioblastoma patients due to its high physical dose conformity and greater biological effectiveness than photons. However, the biological effects of carbon ion radiation are still incompletely understood. Here, we systematically compared the biological effects of clinically used carbon ion radiation to photon radiation with emphasis on DNA repair.

Metformin Enhanced Radiosensitivity Associates with G2/M Cell Cycle Arrest and Elevated Adenosine-5'-monophosphate-activated Protein Kinase Levels in Glioblastoma.

Background: It is hypothesized that metabolism plays a strong role in cancer cell regulation. We have recently demonstrated improved progression-free survival in patients with glioblastoma who received metformin as an antidiabetic substance during chemoradiation. Although metformin is well-established in clinical use the influence of metformin in glioblastoma is far from being understood especially in combination with other treatment modalities such as radiation and temozolomide.

Phytotherapeutics Oridonin and Ponicidin show Additive Effects Combined with Irradiation in Pancreatic Cancer .

Background: Chemoradiation of locally advanced non-metastatic pancreatic cancer can lead to secondary operability by tumor mass reduction. Here, we analyzed radiomodulating effects of oridonin and ponicidin in pancreatic cancer . Both agents are ent-kaurane diterpenoids, extracted from , a plant that is well known in Traditional Chinese Medicine.

Human mesenchymal stem cells lose their functional properties after paclitaxel treatment.

Mesenchymal stem cells (MSCs) are an integral part of the bone marrow niche and aid in the protection, regeneration and proliferation of hematopoietic stem cells after exposure to myelotoxic taxane anti-cancer agents, but the influence of taxane compounds on MSCs themselves remains incompletely understood. Here, we show that bone marrow-derived MSCs are highly sensitive even to low concentrations of the prototypical taxane compound paclitaxel. While MSCs remained metabolically viable, they were strongly impaired regarding both their proliferation and their functional capabilities after exposure to paclitaxel.

Cisplatin radiosensitizes radioresistant human mesenchymal stem cells.

Cisplatin-based chemo-radiotherapy is widely used to treat cancers with often severe therapy-associated late toxicities. While mesenchymal stem cells (MSCs) were shown to aid regeneration of cisplatin- or radiation-induced tissue lesions, the effect of the combined treatment on the stem cells remains unknown. Here we demonstrate that cisplatin treatment radiosensitized human bone marrow-derived MSCs in a dose-dependent manner and increased levels of radiation-induced apoptosis.

Low-dose photon irradiation induces invasiveness through the SDF-1α/CXCR4 pathway in malignant mesothelioma cells.

Background: Low-dose photon irradiation has repeatedly been suspected to increase a risk of promoting local recurrence of disease or even systemic dissemination. The purpose of this study was to investigate the motility of malignant pleural mesothelioma (MPM) cell lines after low-doses of photon irradiation and to elucidate the mechanism of the detected phenotype.

Methods: H28 and H226 MPM cells were examined in clonogenic survival experiments and migration assays with and without various doses of photon and carbon ion irradiation.

Sulforaphane enhances irradiation effects in terms of perturbed cell cycle progression and increased DNA damage in pancreatic cancer cells.

Background: Sulforaphane (SFN), an herbal isothiocyanate enriched in cruciferous vegetables like broccoli and cauliflower, has gained popularity for its antitumor effects in cell lines such as pancreatic cancer. Antiproliferative as well as radiosensitizing properties were reported for head and neck cancer but little is known about its effects in pancreatic cancer cells in combination with irradiation (RT).

Methods: In four established pancreatic cancer cell lines we investigated clonogenic survival, analyzed cell cycle distribution and compared DNA damage via flow cytometry and western blot after treatment with SFN and RT.

Comparative analysis of the effects of a sphingosine kinase inhibitor to temozolomide and radiation treatment on glioblastoma cell lines.

Glioblastoma multiforme (GBM) exhibits high resistance to the standard treatment of temozolomide (TMZ) combined with radiotherapy, due to its remarkable cell heterogeneity. Accordingly, there is a need to target alternative molecules enhancing specific GBM autocrine or paracrine mechanisms and amplifying the effect of standard treatment. Sphingosine 1-phosphate (S1P) is such a lipid target molecule with an important role in cell invasion and proliferation.

Combination of Photon and Carbon Ion Irradiation with Targeted Therapy Substances Temsirolimus and Gemcitabine in Hepatocellular Carcinoma Cell Lines.

Background: This work investigates on putative cytotoxic effects in four different hepatocellular carcinoma (HCC) cell lines after irradiation with photons or carbon ions in combination with new targeted molecular therapy using either Temsirolimus (TEM) or Gemcitabine (GEM).

Methods And Materials: The HCC cell lines HepG2, Hep3B, HuH7, and PLC were cultured and irradiated with photons or carbon ions at the Heidelberg Ion Beam Therapy Center using the raster-scanning method. For combination experiments, cell lines were first treated with Temsirolimus or GEM before irradiation.

Regulation of submaxillary gland androgen-regulated protein 3A via estrogen receptor 2 in radioresistant head and neck squamous cell carcinoma cells.

Background: Molecular mechanisms of intrinsic or acquired radioresistance serve as critical barrier for curative therapy of head and neck squamous cell carcinoma (HNSCC) and remain a major obstacle for progression-free and disease-specific survival.

Methods: HNSCC cell lines were treated with a protocol of fractionated irradiation (IR, 4× 2Gy) alone or in combination with antagonists of estrogen receptor signaling and viability was determined by a colony-forming assay (CFA). Expression of submaxillary gland androgen-regulated protein 3A (SMR3A) and estrogen receptor 2 (ESR2) were assessed in tumor cells in vitro by RQ-PCR, Western blot analysis and immunofluorescence staining, and by immunohistochemical staining of tissue microarrays containing tumor sections from patients with oropharyngeal squamous cell carcinoma (OPSCC), which were treated by definitive or adjuvant radiotherapy.

Dedicated high dose rate Ir brachytherapy radiation fields for in vitro cell exposures at variable source-target cell distances: killing of mammalian cells depends on temporal dose rate fluctuation.

Afterloading brachytherapy is conducted by the stepwise movement of a radioactive source through surgically implanted applicator tubes where at predefined dwell positions calculated dwell times optimize spatial dose delivery with respect to a planned dose level. The temporal exposure pattern exhibits drastic fluctuations in dose rate at a given coordinate and within a single treatment session because of the discontinuous and repeated source movement into the target volume. This could potentially affect biological response.

Mesenchymal stem cells are sensitive to bleomycin treatment.

Mesenchymal stem cells (MSCs) have been shown to attenuate pulmonary damage induced by bleomycin-based anticancer treatments, but the influence of bleomycin on the stem cells themselves remains largely unknown. Here, we demonstrate that human bone marrow-derived MSCs are relatively sensitive to bleomycin exposure compared to adult fibroblasts. MSCs revealed increased levels of apoptosis after bleomycin treatment, while cellular morphology, stem cell surface marker expression and the ability for adhesion and migration remained unchanged.

Superresolution light microscopy shows nanostructure of carbon ion radiation-induced DNA double-strand break repair foci.

Carbon ion radiation is a promising new form of radiotherapy for cancer, but the central question about the biologic effects of charged particle radiation is yet incompletely understood. Key to this question is the understanding of the interaction of ions with DNA in the cell's nucleus. Induction and repair of DNA lesions including double-strand breaks (DSBs) are decisive for the cell.

Targeting irradiation-induced mitogen-activated protein kinase activation in vitro and in an ex vivo model for human head and neck cancer.

Background: Despite new radiotherapeutic strategies, radioresistance in head and neck squamous cell carcinoma (HNSCC) remains a major problem. Preclinical model systems are needed to identify resistance mechanisms in this heterogeneous entity.

Methods: We elucidated the interplay among mitogen-activated protein kinase (MAPK)-inhibition, radiation, and p53 mutations in vitro and in a novel ex vivo model derived from vital human HNSCC samples.

Mesenchymal stem cells exhibit resistance to topoisomerase inhibition.

Background: Inhibition of cellular topoisomerases has been established as an effective way of treating certain cancers, albeit with often high levels of toxicity to the bone marrow. While the involvement of mesenchymal stem cells (MSCs) in bone marrow homeostasis and regeneration has been well established, the effects of topoisomerase-inhibiting anticancer agents remain largely unknown.

Materials And Methods: Human bone marrow MSCs were treated with topoisomerase I inhibitor irinotecan or topoisomerase II inhibitor etoposide, and survival and apoptosis levels were measured.

Mesenchymal stem cells maintain their defining stem cell characteristics after treatment with cisplatin.

Mesenchymal stem cells (MSCs) aid the regeneration of tissues damaged by treatment with cisplatin. However, the effects of this cytotoxic drug on the stem cells have been largely unknown. Here we demonstrate that human bone marrow-derived MSCs are relatively resistant to cisplatin treatment and show resistance levels comparable to these of differentiated fibroblasts.

S-phase-specific radiosensitization by gemcitabine for therapeutic carbon ion exposure in vitro.

Densely ionizing charged particle irradiation offers physical as well as biological advantages compared with photon irradiation. Radiobiological data for the combination of such particle irradiation (i.e.

Impaired aldehyde dehydrogenase 1 subfamily member 2A-dependent retinoic acid signaling is related with a mesenchymal-like phenotype and an unfavorable prognosis of head and neck squamous cell carcinoma.

Background: An inverse correlation between expression of the aldehyde dehydrogenase 1 subfamily A2 (ALDH1A2) and gene promoter methylation has been identified as a common feature of oropharyngeal squamous cell carcinoma (OPSCC). Moreover, low ALDH1A2 expression was associated with an unfavorable prognosis of OPSCC patients, however the causal link between reduced ALDH1A2 function and treatment failure has not been addressed so far.

Methods: Serial sections from tissue microarrays of patients with primary OPSCC (n = 101) were stained by immunohistochemistry for key regulators of retinoic acid (RA) signaling, including ALDH1A2.

Kallikrein-related peptidase 6 regulates epithelial-to-mesenchymal transition and serves as prognostic biomarker for head and neck squamous cell carcinoma patients.

Background: Dysregulated expression of Kallikrein-related peptidase 6 (KLK6) is a common feature for many human malignancies and numerous studies evaluated KLK6 as a promising biomarker for early diagnosis or unfavorable prognosis. However, the expression of KLK6 in carcinomas derived from mucosal epithelia, including head and neck squamous cell carcinoma (HNSCC), and its mode of action has not been addressed so far.

Methods: Stable clones of human mucosal tumor cell lines were generated with shRNA-mediated silencing or ectopic overexpression to characterize the impact of KLK6 on tumor relevant processes in vitro.

Evaluation of chemoradiotherapy with carbon ions and the influence of p53 mutational status in the colorectal carcinoma cell line HCT 116.

Aims And Background: Heavy ion therapy has shown promising results in the treatment of recurrent colorectal carcinoma. The present study evaluates the effect of five different cytostatic agents in combination with radiotherapy with carbon (C12) ions and photons in two isogenic colorectal cancer cell lines differing in p53 status.

Methods And Study Design: Clonogenic survival analyses were performed using the human colon cancer cell lines HCT 116 wt and the isogenic p53 deficient cell line HCT 116 p53 -/-.

Mesenchymal stem cells are resistant to carbon ion radiotherapy.

Mesenchymal stem cells (MSCs) participate in regeneration of tissues damaged by ionizing radiation. However, radiation can damage MSCs themselves. Here we show that cellular morphology, adhesion and migration abilities were not measurably altered by photon or carbon ion irradiation.

The relative biological effectiveness for carbon and oxygen ion beams using the raster-scanning technique in hepatocellular carcinoma cell lines.

Background: Aim of this study was to evaluate the relative biological effectiveness (RBE) of carbon (12C) and oxygen ion (16O)-irradiation applied in the raster-scanning technique at the Heidelberg Ion beam Therapy center (HIT) based on clonogenic survival in hepatocellular carcinoma cell lines compared to photon irradiation.

Methods: Four human HCC lines Hep3B, PLC, HepG2 and HUH7 were irradiated with photons, 12C and 16O using a customized experimental setting at HIT for in-vitro trials. Cells were irradiated with increasing physical photon single doses of 0, 2, 4 and 6 Gy and heavy ion-single doses of 0, 0.

Integrin-based meningioma cell migration is promoted by photon but not by carbon-ion irradiation.

Purpose: Sublethal doses of photon irradiation (IR) are suspected to increase tumor cell migration and support locoregional recurrence of disease, which has already been shown in other cell lines. This manuscript describes the effect of photon and carbon-ion IR on WHO class I meningioma cell migration and provides an approach to the underlying cellular mechanisms.

Materials And Methods: Meningioma cells were gained operatively at the university hospital in Homburg/Saar, Germany.