Abstract
Background. Radiosensitizers are used in order to increase the efficacy of radiotherapy. Most of the presently known radiosensitizing agents have a poor selectivity and are not tumour-specific. Porphyrins have a selective uptake in tumour relative to the surrounding normal tissue. The aim of the present work was to test the capability of two photosensitizers – hematoporphyrin derivative (HpD) or temoporfin (mTHPC) – and gamma rays to produce some kind of selective inhibition of tumour cell proliferation. Materials and methods. Dark toxicity experiments were carried out using a sensitizer concentration range 0–50 μg/ml for HpD, or 0–5 μg/ml for mTHPC. For the radiosensitized treatment of rat C6 glioma cells, HpD was added at a final concentration of 1 μg/ml and mTHPC at a final concentration of 0.1 μg/ml. The irradiation with gamma rays was performed using doses ranging from 0 to 8 Gy. Cell survival was determined using the colony forming assay. Results. HpD (1 μg/ml) and mTHPC (0.1 μg/ml) were found to have no toxic effects on C6 glioma cells. A cytotoxic dose without drugs, inducing a reduction in colony survival by 20%, was achieved at 2 Gy and by 50% at 4 Gy. The radiosensitized treatment of cells with HpD resulted in a significant (p ≤ 0.05) decline in cell survival as compared with irradiation alone. For C6 treated with mTHPC, the results did not differ between the two groups (with and without the drug). Conclusions. The results of this study have shown that mTHPC (0.1 μg/ml) does not act as a radiosensitizer, whereas HpD can act, under certain conditions, as a tumour radiosensitizer. These findings suggest that HpD is a potential agent in combination with radiation therapy of malignant gliomas. Keywords: rat C6 glioma cells, radiosensitization, porphyrins, colony forming assay
Highlights
Primary brain tumours are among the ten most common causes of cancer-related death [1]
We show here that the hematoporphyrin derivative sensitizes C6 glioma cells to ionizing radiation, suggesting that HpD may be a useful drug in combination therapy for patients with malignant gliomas [23]
The dark toxicity experiments were carried out using a sensitizer concentration range of 0–50 μg/ml for HpD, or 0–5 μg/ml for mTHPC
Summary
Primary brain tumours are among the ten most common causes of cancer-related death [1]. The most common type of brain tumours in adults, present a remarkable degree of neovascularisation and invasiveness into the surrounding tissues. These features account for their poor prognosis, and combinations of surgery, radiotherapy and chemotherapy with temozolomide. As an approach to overcome this disadvantage, many studies have been carried out to determine whether different photosensitizers sensitize cells and tumours to ionizing radiation. The results of these studies, have been contradictory [12,13,14,15,16]. The aim of the present work was to test the capability of two photosensitizers – hematoporphyrin derivative (HpD) or temoporfin (mTHPC) – and gamma rays to produce some kind of selective inhibition of tumour cell proliferation
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
