Effect of Irradiation on Tumor Microenvironment and Bone Marrow Cell Migration in a Preclinical Tumor Model.

Purpose: To characterize the tumor microenvironment after standard radiation therapy (SRT) and pulsed radiation therapy (PRT) in Lewis lung carcinoma (LLC) allografts.

Methods And Materials: Subcutaneous LLC tumors were established in C57BL/6 mice. Standard RT or PRT was given at 2 Gy/d for a total dose of 20 Gy using a 5 days on, 2 days off schedule to mimic clinical delivery.

Pulsed Radiation Therapy With Concurrent Cisplatin Results in Superior Tumor Growth Delay in a Head and Neck Squamous Cell Carcinoma Murine Model.

Purpose: To assess the efficacy of 3-week schedules of low-dose pulsed radiation treatment (PRT) and standard radiation therapy (SRT), with concurrent cisplatin (CDDP) in a head and neck squamous cell carcinoma xenograft model.

Methods And Materials: Subcutaneous UT-SCC-14 tumors were established in athymic NIH III HO female mice. A total of 30 Gy was administered as 2 Gy/d, 5 d/wk for 3 weeks, either by PRT (10 × 0.

The Effects of Pulsed Radiation Therapy on Tumor Oxygenation in 2 Murine Models of Head and Neck Squamous Cell Carcinoma.

Purpose: To evaluate the efficacy of low-dose pulsed radiation therapy (PRT) in 2 head and neck squamous cell carcinoma (HNSCC) xenografts and to investigate the mechanism of action of PRT compared with standard radiation therapy (SRT).

Methods And Materials: Subcutaneous radiosensitive UT-SCC-14 and radioresistant UT-SCC-15 xenografts were established in athymic NIH III HO female mice. Tumors were irradiated with 2 Gy/day by continuous standard delivery (SRT: 2 Gy) or discontinuous low-dose pulsed delivery (PRT: 0.

Hematopoietic stem and progenitor cell migration after hypofractionated radiation therapy in a murine model.

Purpose: To characterize the recruitment of bone marrow (BM)-derived hematopoietic stem and progenitor cells (HSPCs) within tumor microenvironment after radiation therapy (RT) in a murine, heterotopic tumor model.

Methods And Materials: Lewis lung carcinoma tumors were established in C57BL/6 mice and irradiated with 30 Gy given as 2 fractions over 2 days. Tumors were imaged with positron emission tomography/computed tomography (PET/CT) and measured daily with digital calipers.

Determining if low dose hyper-radiosensitivity (HRS) can be exploited to provide a therapeutic advantage: a cell line study in four glioblastoma multiforme (GBM) cell lines.

Purpose: To determine if ultra-fractionation using repeated pulses of radiation (10 × 0.2 Gray [Gy]) would be more cytotoxic than continuously-delivered radiation to the same total dose (2 Gy) in four glioma cell lines.

Materials And Methods: Human T98G, U373, U87MG and U138MG cells were conventionally X-irradiated with 0.

Pulsed versus conventional radiation therapy in combination with temozolomide in a murine orthotopic model of glioblastoma multiforme.

Purpose: To evaluate the efficacy of pulsed low-dose radiation therapy (PLRT) combined with temozolomide (TMZ) as a novel treatment approach for radioresistant glioblastoma multiforme (GBM) in a murine model.

Methods And Materials: Orthotopic U87MG hGBM tumors were established in Nu-Foxn1(nu) mice and imaged weekly using a small-animal micropositron emission tomography (PET)/computed tomography (CT) system. Tumor volume was determined from contrast-enhanced microCT images and tumor metabolic activity (SUVmax) from the F18-FDG microPET scan.

Pulsed low-dose irradiation of orthotopic glioblastoma multiforme (GBM) in a pre-clinical model: effects on vascularization and tumor control.

Background And Purpose: To compare dose-escalated pulsed low-dose radiation therapy (PLRT) and standard radiation therapy (SRT).

Methods And Materials: Intracranial U87MG GBM tumors were established in nude mice. Animals received whole brain irradiation with daily 2-Gy fractions given continuously (SRT) or in ten 0.

Flow cytometric DNA analysis of human cancers and cell lines.

Measurement of DNA content was one of the first applications to be developed in the use of flow cytometry and is still used routinely in many experimental and, to a lesser extent, clinical studies. The goal of this technique is to produce a high quality DNA profiles for accurate analysis of DNA content and cell cycle distribution. In this chapter, we describe three DNA measurement methods that satisfy this requirement in different situations.

TMPRSS2/ERG fusion gene expression alters chemo- and radio-responsiveness in cell culture models of androgen independent prostate cancer.

Purpose/objectives: The androgen regulated transmembrane serine protease (TMPRSS2) and ETS transcription factor (ERG) gene fusion is a strong prognostic factor for disease recurrence following prostatectomy. Expression of TMPRSS2/ETS-related gene (ERG) fusion gene transcripts is linked with tumor proliferation, invasion, and an aggressive phenotype. The aim of this study was to define the effect of TMPRSS2/ERG fusion gene expression on chemo- and radiosensitivity in prostate tumor cell lines.

The effects of G2-phase enrichment and checkpoint abrogation on low-dose hyper-radiosensitivity.

Purpose: An association between low-dose hyper-radiosensitivity (HRS) and the "early" G2/M checkpoint has been established. An improved molecular understanding of the temporal dynamics of this relationship is needed before clinical translation can be considered. This study was conducted to characterize the dose response of the early G2/M checkpoint and then determine whether low-dose radiation sensitivity could be increased by synchronization or chemical inhibition of the cell cycle.

Transition in survival from low-dose hyper-radiosensitivity to increased radioresistance is independent of activation of ATM Ser1981 activity.

Purpose: The molecular basis of low-dose hyper-radiosensitivity (HRS) is only partially understood. The aim of this study was to define the roles of ataxia telangiectasia mutated (ATM) activity and the downstream ATM-dependent G(2)-phase cell cycle checkpoint in overcoming HRS and triggering radiation resistance.

Methods And Materials: Survival was measured using a high-resolution clonogenic assay.