Trans sodium crocetinate: functional neuroimaging studies in a hypoxic brain tumor

The Anti-hypoxia Potentials of Trans-sodium Crocetinate in Hypoxiarelated Diseases: A Review

Crocetin is a kind of apocarotenoid carboxylic acid extracted from saffron (Crocus sativus L.), which is effective in upregulating tissue oxygenation. However, crocetin is difficult to solubilize. It was shown that the trans isomer of crocetin is effective in improving oxygen diffusivity, while its cis isomer appears not to be. Hence, the isolated trans isomer of crocetin or trans-sodium crocetinate (TSC) can be used instead of crocetin. It is shown that TSC can upregulate hypoxic tissue oxygenation and be effective in treating some hypoxia-related diseases. Moreover, experimental and clinical studies have reported no adverse effects following TSC treatment, even at high doses. The current study will discuss the potential role of TSC in hemorrhagic shock, ischemia, brain tumor radiotherapy, and others.

Herbal nutraceuticals: safe and potent therapeutics to battle tumor hypoxia

PURPOSE

Growing solid tumors mostly outstrip blood supply and become hypoxic (low oxygen supply). To survive under this pathological milieu, tumors overexpress a potent oncogenic factor, hypoxia-inducible factor-1α (HIF-1α). HIF-1α up-regulate HIF-1 signaling pathways and subsequently activate genes that promote cancer growth even under hypoxia. Also, HIF-1 pathway activation leads to aggressive tumor growth, metastasis, therapy resistance and ultimately poor patient prognosis as evidential by several clinical studies. Hence, targeting HIF-1 pathway is regarded as a promising strategy to treat cancer. To date, several synthetic HIF-1 pathway inhibitors have been developed to treat hypoxic tumors; however, they are clinically ineffective due to off-target effects, low potency and high toxicity. Hence, there is an urgent need to explore safe and promising drugs to combat hypoxic tumors.

RESULTS

This article extensively reviews the therapeutic potential of various herbal nutraceuticals against wide varieties of hypoxic tumors. The inhibitory effects of each herbal nutraceutical on the pathological consequences of HIF-1 signaling pathway and also their ability to improve the response of hypoxic cancer cells to conventional cancer therapies are discussed. Furthermore, we have provided new directions to overcome challenges behind conducting in vivo and preclinical hypoxia research and developing herbal nutraceuticals into pharmaceuticals to treat cancer.

CONCLUSIONS

The present review strongly suggests that herbal nutraceuticals are highly effective in combating the oncogenic effects of the HIF-1 pathway in wide varieties of tumors. However, more in vivo studies using zebrafish as a model system and extensive clinical studies in cancer patients with elevated tumor HIF-1α levels are highly warranted to ascertain the effective utilization of herbal nutraceuticals as adjunct/ alternative medicine in clinical practice to treat cancer.

Impact of [64Cu][Cu(ATSM)] PET/CT in the evaluation of hypoxia in a patient with Glioblastoma: a case report

BACKGROUND

Glioblastoma multiform (GBM), a malignant brain tumour, has a very often poor prognosis. The therapeutic approach is represented by surgery followed by radiotherapy and chemotherapy. Hypoxia is a factor that causes a reduction of both radiotherapy and chemotherapy effectiveness in GBM and other cancers. Through the use of [⁶⁴Cu][Cu(ATSM)], a hypoxia-targeting positron emission tomography (PET) radiotracer, is possible to identify the presence of hypoxic areas within a lesion and therefore modulate the therapeutic approach according to the findings.

CASE PRESENTATION

In this case report, we observed an increase of radiotracer uptake from early acquisition to late acquisition in hypoxia sites and high correlation between [⁶⁴Cu][Cu(ATSM) PET/CT results and expression of the hypoxia marker HIF-1α.

CONCLUSIONS

[⁶⁴Cu][Cu(ATSM) PET/CT represents a valid opportunity to reveal in vivo hypoxic areas in GBM lesion which can guide clinicians on selecting GMB patient's therapeutic scheme.

Radiosensitization of Hs-766T Pancreatic Tumor Xenografts in Mice Dosed with Dodecafluoropentane Nano-Emulsion-Preliminary Findings

Tumor hypoxia is an important mediator of radiation therapy resistance. We conducted a study to investigate whether an oxygen therapeutic based upon dodecafluoropentane (DDFP) nano-emulsion (NVX-108) could increase tumor PO2 in hypoxic tumors and improve radiation response. Pancreatic (Hs-766T) tumor xenografts were grown in the flanks of 29 SCID mice. Direct tumor PO2 measurements were performed in 9 mice treated with 0.3, 0.45 and 0.6 cc/kg NVX-108 (2% w/vol DDFP) in order to assess the dose dependent increase in tumor PO2. Twenty mice were randomized into 3 groups including control (no treatment), carbogen breathing treated with 12 Gy radiation, and carbogen breathing treated with 12 Gy radiation and NVX-108 (0.6 cc/kg NVX-108 administered as 30 minute IV infusion at time of radiation). Tumor volume was monitored to assess treatment efficacy. Results showed that tumor PO2 increased in NVX-108 treated mice up to 400% with the greatest effect seen at the highest dose of 0.6 cc/kg. Tumor growth was significantly reduced in both treatment groups relative to controls (p < 0.0001). The combination of carbogen, radiation, and NVX-108 demonstrated a 2-fold reduction in average tumor volume compared to carbogen plus radiation treatment (p = 0.01). Further study of NVX-108 as a radiation sensitizer is warranted.

Standardized uptake value in high uptake area on positron emission tomography with 18F-FRP170 as a hypoxic cell tracer correlates with intratumoral oxygen pressure in glioblastoma

PURPOSE

The aim of this study was to clarify the reliability of positron emission tomography (PET) using a new hypoxic cell tracer, 1-(2-[(18)F]fluoro-1-[hydroxymethyl]ethoxy)methyl-2-nitroimidazole ((18)F-FRP170).

PROCEDURES

Twelve patients with glioblastoma underwent (18)F-FRP170 PET before tumor resection. Mean standardized uptake value (SUV) and normalized SUV were calculated at regions within a tumor showing high (high-uptake area) and relatively low (low-uptake area) accumulations of (18)F-FRP170. In these areas, intratumoral oxygen pressure (tpO2) was measured using microelectrodes during tumor resection.

RESULTS

Mean tpO2 was significantly lower in the high-uptake area than in the low-uptake area. A significant negative correlation was evident between normalized SUV and tpO2 in the high-uptake area.

CONCLUSION

The present findings suggest that high accumulation on (18)F-FRP170 PET represents viable hypoxic tissues in glioblastoma.

Characterization of biological features of a rat F98 GBM model: a PET-MRI study with [18F]FAZA and [18F]FDG

INTRODUCTION

The prognosis of malignant gliomas remains largely unsatisfactory for the intrinsic characteristics of the pathology and for the delayed diagnosis. Multimodal imaging based on PET and MRI may assess the dynamics of disease onset and progression allowing the validation of preclinical models of glioblastoma multiforme (GBM). The aim of this study was the characterization of a syngeneic rat model of GBM using combined in vivo imaging and immunohistochemistry.

METHODS

Four groups of Fischer rats were implanted in a subcortical region with increasing concentration of rat glioma F98 cells and weekly monitored with Gd-MR, [(18)F]FDG- and [(18)F]FAZA-PET starting one week after surgery. Different targets were evaluated on post mortem brain specimens using immunohistochemistry: VEGF, GFAP, HIF-1α, Ki-67 and nestin.

RESULTS

Imaging results indicated that tumor onset but not progression was related to the number of F98 cells. Hypoxic regions identified with [(18)F]FAZA and high-glucose metabolism regions recognized with [(18)F]FDG were located respectively in the core and in external areas of the tumor, with partial overlap and remodeling during disease progression. Histological and immunohistochemical analysis confirmed PET/MRI results and revealed that our model resumes biological characteristics of human GBM. IHC and PET studies showed that necrotic regions, defined on the basis of [(18)F]FDG uptake reduction, may include hypoxic clusters of vital tumor tissue identified with [(18)F]FAZA. This last information is particularly relevant for the identification of the target volume during image-guided radiotherapy.

CONCLUSIONS

In conclusion, the combined use of PET and MRI allows in vivo monitoring of the biological modification of F98 lesions during tumor progression.

Application of 62Cu-diacetyl-bis (N4-methylthiosemicarbazone) PET imaging to predict highly malignant tumor grades and hypoxia-inducible factor-1α expression in patients with glioma

BACKGROUND AND PURPOSE

Hypoxic tissue evaluation in glioma is important for predicting treatment response and establishing antihypoxia therapy. In this preliminary study, (62)Cu-ATSM PET was used to determine its validity as a biomarker for distinguishing tumor grade and tissue hypoxia.

MATERIALS AND METHODS

(62)Cu-ATSM PET was performed in 22 patients with glioma, and the (62)Cu-ATSM SUV(max) and T/B ratio were semiquantitatively evaluated. (62)Cu-ATSM uptake distribution was qualitatively evaluated and compared with MR imaging findings. HIF-1α expression, a hypoxia marker, was compared with (62)Cu-ATSM uptake values.

RESULTS

The (62)Cu-ATSM SUV(max) and T/B ratio were significantly higher in grade IV than in grade III gliomas (P = .014 and .018, respectively), whereas no significant differences were found between grade III and grade II gliomas. At a T/B ratio cutoff threshold of 1.8, (62)Cu-ATSM uptake was predictive of HIF-1α expression, with 92.3% sensitivity and 88.9% specificity. The mean T/B ratio was also significantly higher in HIF-1α-positive glioma tissue than in HIF-1α-negative tissue (P = .001). Using this optimal threshold of T/B ratio, (62)Cu-ATSM PET showed regional uptake in 61.9% (13/21) of tumors within the contrast-enhanced region on MR imaging, which was significantly correlated with presence of a necrotic component (P = .002).

CONCLUSIONS

Our results demonstrated that (62)Cu-ATSM uptake is relatively high in grade IV gliomas and correlates with the MR imaging findings of necrosis. Moreover, the (62)Cu-ATSM T/B ratio showed significant correlation with HIF-1α expression. Thus, (62)Cu-ATSM appears to be a suitable biomarker for predicting highly malignant grades and tissue hypoxia in patients with glioma.

The role of adjuvant radiation therapy in the management of high-grade gliomas

The purpose of this article is to update the neurosurgical community on the role of adjuvant radiation therapy in the management of patients with high-grade glioma. This information guides clinicians in the multidisciplinary management of these patients via a review of the literature describing current treatment paradigms as well as new avenues of investigation.