Motexafin gadolinium injection for the treatment of brain metastases in patients with non-small cell lung cancer

Preparation and quality control of a new porphyrin complex labeled with 45Ti for PET imaging

This study aims to produce and quality control of a new porphyrin complex labeled with ⁴⁵Ti for PET imaging, so at the first step, the cross-section of ⁴⁵Sc(p,n)⁴⁵Ti was investigated by TALYS-1.6 and the optimal target thickness and theoretical yield were calculated by SRIM code. The purified ⁴⁵Ti was labeled with the anticancer agent of tetrakis (pentafluorophenyl) porphyrin (TFPP). The radiochemical purity and the percentage of labeling were evaluated by radiation layer chromatography then the division coefficient of [⁴⁵Ti]-TFPP was calculated. The dual coincidence imaging system was used for imaging 1 and 2 h after injection [⁴⁵Ti]-TFPP to rats. Immediately after imaging, the mean percent injected dose per gram and specific activity of different tissues including blood, heart, lungs, stomach, liver, bone, kidney, spleen, intestine, muscle, feces, and skin were measured. The yield of ⁴⁵Ti production was measured 468 MBq/μAh and the labeling rate was observed more than 98%. The highest activity was observed in the liver (%ID/g = 2.27%, 1 h) and spleen (2.2%, 1 h), respectively, because of the high lipophilic of ⁴⁵Ti-TFPP. SPECT images showed a significant uptake of radiopharmaceuticals in the abdomen. The labeling rate of ⁴⁵Ti-TFPP was high and this compound has the potential for clinical application in different ways than PSMA, it can be joined with photodynamic therapy (Severin et al., 2015).

Continuous Low-Dose Apatinib Combined With WBRT Significantly Reduces Peritumoral Edema and Enhances the Efficacy of Symptomatic Multiple Brain Metastases in NSCLC

BACKGROUND

Symptomatic multiple brain metastases with peritumoral brain edema (PTBE) occur in non-small cell lung cancer patients (NSCLC) who are without driver mutations or are resistant to epidermal growth factor tyrosine kinase (EGFR-TKI) are often associated with an unfavorable prognosis. Whole brain radiation therapy (WBRT) which comes with many complications and unsatisfactory effects, is the only option for the treatment. Previous studies have shown that bevacizumab can reduce the volume of PTBE and improve efficiency of radiotherapy. This study evaluated the effects and safety of apatinib combined with WBRT in NSCLC patients with symptomatic multiple brain metastases and PTBE.

METHODS

We performed a retrospective review of 34 patients with symptomatic multiple brain metastases from NSCLC (number >4, and at least 1 measurable brain metastasis lesion with cerebral edema). Intracranial objective response rate (IORR), peritumoral edema and intracranial tumor volumetric measurement, Karnofsky performance status (KPS) and adverse events (AEs) were evaluated. Median intracranial progression-free survival (mIPFS) and median overall survival (mOS) were also analyzed.

RESULTS

Thirteen cases received apatinib (125 mg or 250 mg, QD, oral) combined with WBRT and 21 cases received chemotherapy combined with WBRT were inclued. Apatinib combination group can better reduce the volume of intracranial tumors and PTBE and total steroid dosage used. It was associated with a better IORR (84.6% vs 47.6%, P = 0.067), longer mIPFS (6.97 vs 4.77months; P = 0.014). There was no significant difference in mOS(7.70 vs 6.67 months; P = 0.14) between the 2 groups. The most common adverse events of apatinib combination WBRT included grade 1/2 nausea (4/13), fatigue (3/13), hypertension (2/13) and white blood cell decrease (2/13). No grade 3/4 AEs were observed.

CONCLUSION

Apatinib plus WBRT is well tolerated and may be a potential choice for relapsed or drug-resistant advanced NSCLC patients with symptomatic multiple brain metastases and PTBE.

Manganese(II) Texaphyrin: A Paramagnetic Photoacoustic Contrast Agent Activated by Near-IR Light

The NIR absorptivity of the metallotexaphyrin derivatives MMn, MGd, and MLu for photoacoustic (PA)-based imaging is explored in this study. All three complexes demonstrated excellent photostabilities; however, MMn provided the greatest PA signal intensities in both doubly distilled water and RAW 264.7 cells. In vivo experiments using a prostate tumor mouse model were performed. MMn displayed no adverse toxicity to major organs as inferred from hematoxylin and eosin (H&E) staining and cell blood count testing. MMn also allowed for PA-based imaging of tumors with excellent in vivo stability to provide 3D tumor diagnostic information. Based on the present findings and previous magnetic resonance imaging (MRI) studies, we believe MMn may have a role to play either as a stand-alone PA contrast agent or as a single molecule dual modal (PA and MR) imaging agent for tumor diagnosis.

Gadolinium-Rose Bengal Coordination Polymer Nanodots for MR-/Fluorescence-Image-Guided Radiation and Photodynamic Therapy

Combination therapy based on nanomedicine has gained momentum in oncology in recent years, offering superior safety and efficacy over monotherapies. It is critical to design theranostics that are composed of imaging and therapeutic agents already approved. Herein, gadolinium (Gd)-rose bengal coordination polymer nanodots (GRDs) are reported. The GRDs exhibit a unique absorption property and 7.7-fold luminescence enhancement, as well as a 1.9-fold increase in singlet oxygen generation efficiency over free rose bengal. Meanwhile, GRDs exhibit a twofold increase in r₁ relaxivity over gadopentetic acid (Gd-DTPA) and have better X-ray absorption ability than rose bengal alone. These excellent properties of the GRDs are verified both in vitro and in vivo. The combination of photodynamic therapy (PDT) and radiation therapy (RT) more significantly inhibits tumor growth than monotherapies (i.e., PDT or RT). This work offers a new route to designing and synthesizing Gd-based nanotheranostics for image-guided cancer therapy.

Role of Reactive Oxygen Species in Cancer Progression: Molecular Mechanisms and Recent Advancements

Reactive oxygen species (ROS) play a pivotal role in biological processes and continuous ROS production in normal cells is controlled by the appropriate regulation between the silver lining of low and high ROS concentration mediated effects. Interestingly, ROS also dynamically influences the tumor microenvironment and is known to initiate cancer angiogenesis, metastasis, and survival at different concentrations. At moderate concentration, ROS activates the cancer cell survival signaling cascade involving mitogen-activated protein kinase/extracellular signal-regulated protein kinases 1/2 (MAPK/ERK1/2), p38, c-Jun N-terminal kinase (JNK), and phosphoinositide-3-kinase/ protein kinase B (PI3K/Akt), which in turn activate the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), matrix metalloproteinases (MMPs), and vascular endothelial growth factor (VEGF). At high concentrations, ROS can cause cancer cell apoptosis. Hence, it critically depends upon the ROS levels, to either augment tumorigenesis or lead to apoptosis. The major issue is targeting the dual actions of ROS effectively with respect to the concentration bias, which needs to be monitored carefully to impede tumor angiogenesis and metastasis for ROS to serve as potential therapeutic targets exogenously/endogenously. Overall, additional research is required to comprehend the potential of ROS as an effective anti-tumor modality and therapeutic target for treating malignancies.

Emerging Applications of Porphyrins and Metalloporphyrins in Biomedicine and Diagnostic Magnetic Resonance Imaging

In recent years, scientific advancements have constantly increased at a significant rate in the field of biomedical science. Keeping this in view, the application of porphyrins and metalloporphyrins in the field of biomedical science is gaining substantial importance. Porphyrins are the most widely studied tetrapyrrole-based compounds because of their important roles in vital biological processes. The cavity of porphyrins containing four pyrrolic nitrogens is well suited for the binding majority of metal ions to form metalloporphyrins. Porphyrins and metalloporphyrins possess peculiar photochemical, photophysical, and photoredox properties which are tunable through structural modifications. Their beneficial photophysical properties, such as the long wavelength of emission and absorption, high singlet oxygen quantum yield, and low in vivo toxicity, have drawn scientists' interest to discover new dimensions in the biomedical field. Applications of porphyrins and metalloporphyrins have been pursued in the perspective of contrast agents for magnetic resonance imaging (MRI), photodynamic therapy (PDT) of cancer, bio-imaging, and other biomedical applications. This review discusses photophysics and the photochemistry of porphyrins and their metal complexes. Secondly, it explains the current developments and mode of action for contrast agents for MRI. Moreover, the application of porphyrin and metalloporphyrin-based molecules as a photosensitizer in PDT of cancer, the mechanism of the generation of reactive oxygen species (ROS), factors that determine the efficiency of PDT, and the developments to improve this technology are delineated. The last part explores the most recent research and developments on metalloporphyrin-based materials in bio-imaging, drug delivery, and the determination of ferrochelatase in bone marrow indicating their prospective clinical applications.

Gadolinium accumulation in organs of Sprague-Dawley® rats after implantation of a biodegradable magnesium-gadolinium alloy

Biodegradable magnesium implants are under investigation because of their promising properties as medical devices. For enhancing the mechanical properties and the degradation resistance, rare earth elements are often used as alloying elements. In this study Mg10Gd pins were implanted into Sprague-Dawley® rats. The pin volume loss and a possible accumulation of magnesium and gadolinium in the rats' organs and blood were investigated in a long-term study over 36weeks. The results showed that Mg10Gd is a fast disintegrating material. Already 12weeks after implantation the alloy is fragmented to smaller particles, which can be found within the intramedullary cavity and the cortical bones. They disturbed the bone remodeling until the end of the study. The results concerning the elements' distribution in the animals' bodies were even more striking, since an accumulation of gadolinium could be observed in the investigated organs over the whole time span. The most affected tissue was the spleen, with up to 3240μgGd/kg wet mass, followed by the lung, liver and kidney (up to 1040, 685 and 207μgGd/kg). In the brain, muscle and heart, the gadolinium concentrations were much smaller (less than 20μg/kg), but an accumulation could still be detected. Interestingly, blood serum samples showed no accumulation of magnesium and gadolinium. This is the first time that an accumulation of gadolinium in animal organs was observed after the application of a gadolinium-containing degradable magnesium implant. These findings demonstrate the importance of future investigations concerning the distribution of the constituents of new biodegradable materials in the body, to ensure the patients' safety.

STATEMENT OF SIGNIFICANCE

In the last years, biodegradable Mg alloys are under investigation due to their promising properties as orthopaedic devices used for bone fracture stabilization. Gadolinium as Rare Earth Element enhances the mechanical properties of Mg-Gd alloys but its toxicity in humans is still questionable. Up to now, there is no study investigating the elements' metabolism of a REE-containing Magnesium alloy in an animal model. In this study, we examined the gadolinium distribution and accumulation in rat organs during the degradation of Mg10Gd. Our findings showed that Gd is accumulating in the animal organs, especially in spleen, liver and kidney. This study is of crucial benefit regarding a safe application of REE-containing Magnesium alloys in humans.

Updating advances on recombinant human endostatin combined with radiotherapy for non-small cell lung cancer with brain metastasis

Brain metastases (BM) heavily affects the prognosis of advanced non-small cell lung cancer (NSCLC). Although whole-brain radiotherapy remains the mainstream therapy for BM caused by NSCLC, the effectiveness is unsatisfactory. Endostar, a recombinant human endostatin (RHES), has shown certain therapeutic effect on advanced NSCLC. This article reviews the feasibility of Endostar combined with radiotherapy in the treatment of BM caused by NSCLC.

Development of a (68)Ga-Fluorinated Porphyrin Complex as a Possible PET Imaging Agent

AIM

Due to the interesting pharmacologic properties of porphyrins, the idea of developing a possible tumor imaging agent using PET by incorporating (68)Ga into a suitable porphyrin ligand was investigated.

METHODS

(68)Ga-labeled 5,10,15,20-tetrakis(pentafluoro-13 phenyl) porphyrin ((68)Ga-TFPP) was prepared using freshly eluted [(68)Ga]GaCl3 obtained from a 68Ge/68Ga generator developed in-house and 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin (H2TFPP) for 60 min at 100°C.

RESULTS

The complex was prepared with high radiochemical purity (>99% ITLC, >99% HPLC, specific activity: 13-14 GBq/mmol). Stability of the complex was checked in the final formulation and in human serum for 5 h. The partition coefficient was calculated for the compound (log P = 0.62). The biodistribution of the labeled compound in vital organs of Swiss mice bearing fibrosarcoma tumors was studied using scarification studies and SPECT imaging up to 1 h. The complex was mostly washed out from the circulation through kidneys and liver. The tumor-to-muscle ratio 1 h post injection was 5.13.

CONCLUSION

The radiolabeled porphyrin complex demonstrated potential for further imaging studies in other tumor models.

Physiological Targeting to Improve Anticancer Drug Selectivity

The physiological differences between solid tumours and the healthy tissues and organs of the body are both an impediment to effective treatment and a potential basis for targeting strategies. In the present review, we outline the physiological features that distinguish tumours including hypoxia, acidity, and inhibited transport and describe the strategies being employed to exploit these differences in order to generate more selective and less toxic anticancer agents.