Publications by authors named "Lars Ekblad"

Background: The epidermal growth factor receptor (EGFR) is pivotal for growth of epithelial cells and is overexpressed in several epithelial cancers like head and neck squamous cell carcinoma (HNSCC). EGFR signalling is also involved in diverse innate immune functions in epithelia. We previously found a role for EGFR in modulating the complement system in skin, this prompted an investigation into EGFR role in complement modulation in HNSCC.

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Well characterized human cell lines are needed for preclinical treatment studies of anaplastic thyroid cancer (ATC). The aim was to establish, verify and characterize a panel of ATC cell lines. Cell lines were established from ATC fine-needle aspiration biopsies and characterized genetically and functionally regarding treatment sensitivities.

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Background: Human papillomavirus (HPV) is an established risk factor for oropharyngeal squamous cell carcinoma (OSCC). The aim was to establish cell lines from HPV-positive tonsil carcinomas to be used for treatment development.

Methods: Fresh samples from 23 HPV-positive tonsil carcinomas were cultivated in vitro.

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Anaplastic thyroid cancer (ATC) is a rare and extremely malignant tumor with no available cure. The genetic landscape of this malignancy has not yet been fully explored. In this study, we performed whole exome sequencing and the RNA-sequencing of fourteen cases of ATC to delineate copy number changes, fusion gene events, and somatic mutations.

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Here we show that treatment of the HPV16-positive tonsillar cancer cell line HN26 with DNA alkylating cancer drug melphalan-induced p53 and activated apoptosis. Melphalan reduced the levels of RNA polymerase II and cellular transcription factor Sp1 that were associated with HPV16 DNA. The resulting inhibition of transcription caused a rapid loss of the HPV16 early mRNAs encoding E6 and E7 as a result of their inherent instability.

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The ETS family transcription factor GABPA is suggested as an oncogenic element, which is further supported by the recent reporting of it as the sole ETS member to activate the mutant TERT promoter in thyroid carcinomas (TC). However, it remains unclear how GABPA contributes to TC pathogenesis. The present study is designed to address this issue.

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We show that the alkylating cancer drug melphalan activated the DNA damage response and induced human papillomavirus type 16 (HPV16) late gene expression in an ATM- and Chk1/2-dependent manner. Activation of HPV16 late gene expression included inhibition of the HPV16 early polyadenylation signal that resulted in read-through into the late region of HPV16. This was followed by activation of the exclusively late, HPV16 splice sites SD3632 and SA5639 and production of spliced late L1 mRNAs.

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It is well known that nonirradiated cells can exhibit radiation damage (bystander effect), and recent findings have shown that nonirradiated cells may help protect irradiated cells (rescue effect). These findings call into question the traditional view of radiation response: cells cannot be envisioned as isolated units. Here, we investigated traditional colony formation assays to determine if they also comprise cellular communication affecting the radiation response, using colony formation assays with varying numbers of cells, modulated beam irradiation and media transfer.

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Objectives: The existence of circulating tumor cells has emerged as an important factor for prognosis and survival. The CellSearch method is the only circulating tumor cell detection method approved by the US Food and Drug Administration for clinical use. It relies on the detection of EpCAM (epithelial cell adhesion molecule) and is approved for colon cancer, breast cancer and prostate cancer.

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We present an experimental method including error analysis for the measurement of the density and compressibility of cells and microbeads; these being the two central material properties in ultrasound-based acoustophoretic applications such as particle separation, trapping, and up-concentration. The density of the microparticles is determined by using a neutrally buoyant selection process that involves centrifuging of microparticles suspended in different density solutions, CsCl for microbeads and Percoll for cells. The speed of sound at 3 MHz in the neutrally buoyant suspensions is measured as a function of the microparticle volume fraction, and from this the compressibility of the microparticles is inferred.

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Anaplastic thyroid cancer (ATC) is a highly malignant disease with a very short median survival time. Few studies have addressed the underlying somatic mutations, and the genomic landscape of ATC thus remains largely unknown. In the present study, we have ascertained copy number aberrations, gene fusions, gene expression patterns, and mutations in early-passage cells from ten newly established ATC cell lines using single nucleotide polymorphism (SNP) array analysis, RNA sequencing and whole exome sequencing.

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Objectives/hypothesis: We investigated whether exposing a wound-healing-sensitive cell line to human wound fluid (HWF) could prime the cells to increase their tumor-forming ability in nude mice and, if so, whether this ability can be inhibited by pharmacological substances.

Study Design: Experimental animal model.

Methods: Take rate was measured in BALB/c nude mice after pretreatment of the cells with HWF using human serum and fetal bovine serum as controls.

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The purpose of this study was to establish an experimental setting and an anesthetic method compatible with future sequential studies using (18)F-FDG-PET single scans, i.e. autoradiographic measurements, for the estimation of metabolic rate of glucose (MRglc) in mice.

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Background: Among head and neck cancers, human papillomavirus type 16 (HPV16) is associated with tonsillar carcinomas. Despite this, no HPV16-positive tonsillar cancer cell line has been established in nude mice.

Methods: Fresh tonsillar carcinoma biopsies were obtained from 23 patients and implanted subcutaneously into nude mice (BALB/c, nu/nu).

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Objectives: Cetuximab is an epidermal growth factor receptor (EGFR)-targeting drug that has shown effects in head and neck squamous cell carcinoma (HNSCC). The effects are, however, small and have mainly been proven in a subset of patients, and the cost-effectiveness has been questioned. For this reason, we need to know more about the basic mechanisms controlling the effect of EGFR signalling on tumour growth.

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Purpose: Anaplastic thyroid carcinoma (ATC) is one of the most aggressive forms of cancer with no curative therapies available. To date, strategies to target ATC by immunotherapy have not been evaluated. We investigated whether ATC would be a suitable target for natural killer (NK) cell-based immunotherapy.

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Background: Several studies on the use of erythropoietin (Epo) to treat anaemia in patients undergoing cancer treatment have shown adverse effects on tumour control and survival. Experimental studies indicate that this could be linked to an interaction with wound healing processes and not an effect on tumour cells per se. We have previously shown that erythropoietin in combination with surgical trauma stimulates tumour growth.

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Background: Local recurrence is a major factor affecting survival after treatment for head and neck squamous cell carcinoma (HNSCC). It is possible that the normal processes involved in wound healing after surgical removal of a primary tumor can boost the regrowth of residual cancer cells, thereby contributing to the recurrent growth. In this work, we collected human wound fluids and used them to investigate the effect of wound healing factors on HNSCC cell lines in vitro.

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Background: Clinical studies have suggested that the epidermal growth factor receptor (EGFR)-inhibiting antibody cetuximab may have better effect in the third-line treatment of metastatic colorectal cancer, after failure of standard chemotherapy including oxaliplatin, compared to using it up-front in the first line. The reason behind this suggestion is unclear.

Materials And Methods: The effect of cetuximab on cell growth was investigated in five isogenic colon cancer cell lines with increasing level of acquired oxaliplatin resistance.

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Purpose: Predictive strategies for the treatment efficacy of cetuximab are currently not available for head and neck cancer. We investigated the correlation between the expression of epidermal growth factor receptor (EGFR) ligands and EGFR expression, and the growth inhibitory activity of cetuximab in a panel of head and neck squamous cell carcinoma (HNSCC) cell lines.

Methods: The growth inhibiting effect of cetuximab was measured for eight HNSCC cell lines and correlated with the autocrine production of five EGFR ligands as measured by ELISA, and the mRNA expression of two ligands, as measured by quantitative RT-PCR.

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The role of chemotherapy (CHX) in squamous cell carcinoma of the head and neck (SCCHN) has been expanding. Although combination chemotherapy regimens regularly produce significantly high response rates, meta-analyses show little benefit regarding final outcome. One way to improve induction CHX is to improve drug combinations and schedules for CHX.

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In Western blotting, immunodetection of housekeeping proteins is routinely performed to detect differences in electrophoresis loading. The present work describes a much faster and simpler protein staining method, which is compatible with ordinary blocking conditions. In addition, the method can be used after immunodetection with superior linearity compared to ordinary staining methods.

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Preclinical studies have indicated that there is only partial cross-resistance between cisplatin and oxaliplatin. The molecular background for this is incompletely known. To investigate the differences in resistance, we rendered a colon cancer cell line (S1) resistant against cisplatin and oxaliplatin and characterized the subclones with regard to cross-resistance, platinum uptake, and gene expression profiles.

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Aim: The aim of this study was to investigate early changes in uptake of 2-deoxy-2-[(18)F]fluoro-D-glucose (FDG) in vivo and in vitro in a squamous-cell carcinoma (SCC) cell line originating from a human head and neck SCC during cytotoxic therapy with respect to metabolism in tumor cells and in surrounding stromal tissue.

Materials And Methods: In 60 nude mice with xenografted SCC, 50 animals were treated with cisplatin. Early changes in the tumor FDG uptake following therapy were evaluated sequentially with phosphor imaging.

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