Fractionated radiation therapy alters energy metabolism and induces cellular quiescence exit in patient-derived orthotopic xenograft models of high-grade glioma.

Radiation is one of the standard therapies for pediatric high-grade glioma (pHGG), of which the prognosis remains poor. To gain an in-depth understanding of biological consequences beyond the classic DNA damage, we treated 9 patient-derived orthotopic xenograft (PDOX) models, including one with DNA mismatch repair (MMR) deficiency, with fractionated radiations (2 Gy/day x 5 days). Extension of survival time was noted in 5 PDOX models (P < 0.05) accompanied by γH2AX positivity in >95 % tumor cells in tumor core and >85 % in the invasive foci as well as ∼30 % apoptotic and mitotic catastrophic cell death. The model with DNA MMR (IC-1406HGG) was the most responsive to radiation with a reduction of Ki-67(+) cells. Altered metabolism, including mitochondria number elevation, COX IV activation and reactive oxygen species accumulation, were detected together with the enrichment of CD133+ tumor cells. The latter was caused by the entry of quiescent G0 cells into cell cycle and the activation of self-renewal (SOX2 and BMI1) and epithelial mesenchymal transition (fibronectin) genes. These novel insights about the cellular and molecular mechanisms of fractionated radiation in vivo should support the development of new radio-sensitizing therapies.

Impact of SCID mouse gender on tumorigenicity, xenograft growth and drug-response in a large panel of orthotopic PDX models of pediatric brain tumors.

Brain tumor is the leading cause of cancer related death in children. Clinically relevant animals are critical for new therapy development. To address the potential impact of animal gender on tumorigenicity rate, xenograft growth and in vivo drug responses, we retrospectively analyzed 99 of our established patient derived orthotopic xenograft mouse models (orthotopic PDX or PDOX). From 27 patient tumors, including 5 glioblastomas (GBMs), 11 medulloblastomas (MBs), 4 ependymomas (EPNs), 4 atypical teratoid/rhabdoid tumors (ATRTs) and 3 diffuse intrinsic pontine gliomas (DIPGs), that were directly implanted into matching locations in the brains of approximately equal numbers of male and female animals (n = 310) in age-matched (within 2-week age-difference) SCID mice, the tumor formation rate was 50.6 ± 21.5% in male and 52.7 ± 23.5% in female mice with animal survival times of 192.6 ± 31.7 days in male and 173.9 ± 34.5 days in female mice (P = 0.46) regardless of pathological diagnosis. Once established, PDOX tumors were serially subtransplanted for up to VII passage. Analysis of 1,595 mice from 59 PDOX models (18 GBMs, 18 MBs, 5 ATRTs, 6 EPNs, 7 DIPGs and 5 PENTs) during passage II and VII revealed similar tumor take rates of the 6 different tumor types between male (85.4 ± 15.5%) and female mice (84.7 ± 15.2%) (P = 0.74), and animal survival times were 96.7 ± 23.3 days in male mice and 99.7 ± 20 days in female (P = 0.25). A total of 284 mice from 7 GBM, 2 MB, 1 ATRT, 1 EPN, 2 DIPG and 1 PNET were treated with a series of standard and investigational drugs/compounds. The overall survival times were 106.9 ± 25.7 days in male mice, and 110.9 ± 31.8 days in female mice (P = 0.41), similar results were observed when different types/models were analyzed separately. In conclusion, our data demonstrated that the gender of SCID mice did not have a major impact on animal model development nor drug responses in vivo, and SCID mice of both genders are appropriate for use.

Raman spectroscopy for optical diagnosis in normal and cancerous tissue of the nasopharynx-preliminary findings.

BACKGROUND AND OBJECTIVES: Raman spectroscopy (RS), which can detect molecular changes associated with cancer, was explored as a means of distinguishing normal and cancerous nasopharyngeal tissue. STUDY DESIGN/PATIENTS AND METHODS: Tissue from six patients with normal and cancerous biopsies was studied using a rapid acquisition Raman spectrometer. RESULTS: Spectra were obtainable within 5 seconds. Consistent differences were noted between normal and cancer tissue in three bands 1,290-1,320 cm(-1) (P = 0.005), 1,420-1,470 cm(-1) (P = 0.006), and 1,530-1,580 cm(-1) (P = 0.002). CONCLUSIONS: Spectral differences appear to exist between normal and cancerous nasopharyngeal tissue. The ability to obtain spectra rapidly supports the potential for future in vivo application.