90Y-oxine-ethiodol, a potential radiopharmaceutical for the treatment of liver cancer

Tuning the lipophilic nature of pyclen-based 90Y3+ radiopharmaceuticals for β-radiotherapy

Pyclen-dipicolinate chelates proved to be very efficient chelators for the radiolabeling with β--emitters such as 90Y. In this study, a pyclen-dipicolinate ligand functionalized with additional C12 alkyl chains was synthesized. The radiolabeling with 90Y proved that the addition of saturated carbon chains does not affect the efficiency of the radiolabeling, whereas a notable increase in lipophilicity of the resulting 90Y radiocomplex was observed. As a result, the compound could be extracted in Lipiodol® and encapsulated in biodegrable pegylated poly(malic acid) nanoparticles demonstrating the potential of lipophilic pyclen-dipicolinate derivatives as platforms for the design of radiopharmaceuticals for the treatment of liver or brain cancers by internal radiotherapy.

Labeling of Hinokitiol with 90Y for Potential Radionuclide Therapy of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC), the most common form of primary liver tumors, is the fifth cancer in the world in terms of incidence, and third in terms of mortality. Despite significant advances in the treatment of HCC, its prognosis remains bleak. Transarterial radioembolization with radiolabeled microspheres and Lipiodol has demonstrated significant effectiveness. Here we present a new, simple radiolabeling of Lipiodol with Yttrium-90, for the potential treatment of HCC.

Transarterial Radioembolization (TARE) Agents beyond 90Y-Microspheres

Liver malignancies, either primary tumours (mainly hepatocellular carcinoma and cholangiocarcinoma) or secondary hepatic metastases, are a major cause of death, with an increasing incidence. Among them, hepatocellular carcinoma (HCC) presents with a dark prognosis because of underlying liver diseases and an often late diagnosis. A curative surgical treatment can therefore only be proposed in 20 to 30% of the patients. However, new treatment options for intermediate to advanced stages, such as internal radionuclide therapy, seem particularly attractive. Transarterial radioembolization (TARE), which consists in the use of intra-arterial injection of a radiolabelled embolising agent, has led to very promising results. TARE with 90Y-loaded microspheres is now becoming an established procedure to treat liver tumours, with two commercially available products (namely, SIR-Sphere® and TheraSphere®). However, this technology remains expensive and is thus not available everywhere. The aim of this review is to describe TARE alternative technologies currently developed and investigated in clinical trials, with special emphasis on HCC.

Demonstrating PM2.5 and road-side dust pollution by heavy metals along Thika superhighway in Kenya, sub-Saharan Africa

This study assessed the level of heavy metal in roadside dust and PM_2.5 mass concentrations along Thika superhighway in Kenya. Thika superhighway is one of the busiest roads in Kenya, linking Thika town with Nairobi. Triplicate road dust samples collected from 12 locations were analysed for lead (Pb), chromium (Cr), cadmium (Cd), nickel (Ni), zinc (Zn), and copper (Cu) using atomic absorption spectrophotometry (AAS). PM_2.5 samples were collected on pre-weighed Teflon filters using a BGI personal sampler and the filters were then reweighed. The ranges of metal concentrations were 39-101 μg/g for Cu, 95-262 μg/g for Zn, 9-28 μg/g for Cd, 14-24 μg/g for Ni, 13-30 μg/g for Cr, and 20-80 μg/g for Pb. The concentrations of heavy metals were generally highly correlated, indicating a common anthropogenic source of the pollutants. The results showed that the majority of the measured heavy metals were above the background concentration, and in particular, Cd, Pb, and Zn levels indicated moderate to high contamination. Though not directly comparable due to different sampling timeframes (8 h in this study and 24 h for guideline values), PM_2.5 for all sites exceeds the daily WHO PM_2.5 guidelines of 25 μg/m³. This poses a health risk to people using and working close to Thika superhighway, for example, local residents, traffic police, street vendors, and people operating small businesses. PM_2.5 levels were higher for sites closer to Nairobi which could be attributed to increased vehicular traffic towards Nairobi from Thika. This study provides some evidence of the air pollution problem arising from vehicular traffic in developing parts of the world and gives an indication of the potential health impacts. It also highlights the need for source apportionment studies to determine contributions of anthropogenic emissions to air pollution, as well as long-term sampling studies that can be used to fully understand spatiotemporal patterns in air pollution within developing regions.

Preliminary evaluation of indigenous 90 Y-labelled microspheres for therapy of hepatocellular carcinoma

Background & objectives:

Yttrium-90 (⁹⁰Y)-based radioembolization has been employed to treat hepatocellular carcinoma (HCC) as commercial radioactive glass and polymeric resin microspheres. However, in India and other Asian countries, these preparations must be imported and are expensive, validating the need for development of indigenous alternatives. This work was aimed to develop an economically and logistically favourable indigenous alternative to imported radioembolizing agents for HCC therapy.

Methods:

The preparation of ⁹⁰Y-labelled Biorex 70 microspheres was optimized and in vitro stability was assessed. Hepatic tumour model was generated in Sprague-Dawley rats by orthotopic implantation of N1S1 rat HCC cell line. In vivo localization and retention of the ⁹⁰Y-labelled Biorex 70 microspheres was assessed for seven days, and impact on N1S1 tumour growth was studied by histological examination and biochemical assays.

Results:

Under optimal conditions, >95% ⁹⁰Y-labelling yield of Biorex70 resin microspheres was obtained, and these showed excellent in vitro stability of labelling (>95%) at seven days. In animal studies, ⁹⁰Y-labelled Biorex 70 microspheres were retained (87.72±1.56% retained in liver at 7 days). Rats administered with ⁹⁰Y-labelled Biorex 70 microspheres exhibited lower tumour to liver weight ratio, reduced serum alpha-foetoprotein level and greater damage to tumour tissue as compared to controls.

Interpretation & conclusions:

⁹⁰Y-labelled Biorex 70 microspheres showed stable retention in the liver and therapeutic effect on tumour tissue, indicating the potential for further study towards clinical use.

Therapeutic Strategies in HCC: Radiation Modalities. Biomed Res Int. 2016;2016:1295329. [PMID: 27563661 PMCID: PMC4987460 DOI: 10.1155/2016/1295329]

Patients with hepatocellular carcinoma (HCC) comply with an advanced disease and are not eligible for radical therapy. In this distressed scenario new treatment options hold great promise; among them transarterial chemoembolization (TACE) and transarterial metabolic radiotherapy (TAMR) have shown efficacy in terms of both tumor shrinking and survival. External radiation therapy (RTx) by using novel three-dimensional conformal radiotherapy has also been used for HCC patients with encouraging results while its role had been limited in the past for the low tolerance of surrounding healthy liver. The rationale of TAMR derives from the idea of delivering exceptional radiation dose locally to the tumor, with cell killing intent, while preserving normal liver from undue exposition and minimizing systemic irradiation. Since the therapeutic efficacy of TACE is being continuously disputed, the TAMR with ¹³¹I Lipiodol or ⁹⁰Y microspheres has gained consideration providing adequate therapeutic responses regardless of few toxicities. The implementation of novel radioisotopes and technological innovations in the field of RTx constitutes an intriguing field of research with important translational aspects. Moreover, the combination of different therapeutic approaches including chemotherapy offers captivating perspectives. We present the role of the radiation-based therapies in hepatocellular carcinoma patients who are not entitled for radical treatment.

Mixed-ligand complexes of yttrium-90 dialkyldithiocarbamates with 1,10-phenanthroline as a possible agent for therapy of hepatocellular carcinoma

Yttrium-90 is a radioelement which has found wide use in targeted radionuclide therapy because of its attractive physical and chemical properties. Radioembolisation of hepatocellular carcinoma with radiolabelled Lipiodol is a method of choice. We have synthesised a series of alkyldithiocarbamate yttrium complexes, easily extracted into Lipiodol due to their high lipophilicity. Among the prepared series, a new radioconjugate, which is stable over an extended period of time, has been prepared, and could represent a potential treatment procedure for hepatocellular carcinoma.

(188)Re-SSS/Lipiodol: Development of a Potential Treatment for HCC from Bench to Bedside

Hepatocellular carcinoma (HCC) is the 5th most common tumour worldwide and has a dark prognosis. For nonoperable cases, metabolic radiotherapy with Lipiodol labelled with β-emitters is a promising therapeutic option. The Comprehensive Cancer Centre Eugène Marquis and the National Graduate School of Chemistry of Rennes (ENSCR) have jointly developed a stable and efficient labelling of Lipiodol with rhenium-188 (E_βmax = 2.1 MeV) for the treatment of HCC. The major “milestones” of this development, from the first syntheses to the recent first injection in man, are described.

Preparation of 177Lu-labeled oxine in lipiodol as a possible agent for therapy of hepatocellular carcinoma: a preliminary animal study

Hepatocellular carcinoma (HCC) is one of the most prevalent forms of cancer with high morbidity. (131)I-lipiodol is used clinically and has been found to be effective for the treatment of HCC. However, this preparation has its limitations, including compromised yield and stability of exchange labeling and unnecessary dose burden from gamma emissions. In the present study, (177)Lu-oxine in lipiodol was considered as a possible alternative for radioiodinated lipiodol. Oxine or 8-hydroxyquinoline was labeled with (177)Lu obtained by neutron irradiation of natural lutetium. Under optimized conditions, the radiolabeled complex was obtained with yields >98% and adequate in vitro stability. (177)Lu-oxine dispersed in lipiodol showed appreciable uptake into rat liver cells (normal and HCC-induced) in vitro. (177)Lu-oxine-lipiodol showed initial localization in the liver, but subsequent leakage of radioactivity with deposition in the skeletal tissue was seen. The studies suggest that (177)Lu-oxine dispersed in lipiodol might not be suitable for treatment of HCC.

Preparation and evaluation of 99mTc(CO)3-labeled pentadecanoic acid derivative and its suspension in lipiodol

Abstract Transarterial embolization by the intra-arterial administration of 131I-lipiodol is a modality used in the treatment of liver cancer. Long-chain fatty acids, being highly lipophilic, are also known to localize in the liver, thus constituting favorable vectors for this modality of treatment. Toward this, we envisaged the derivatization of 15-bromopentadecanoic acid, rendering it suitable for incorporation of a tridentate chelating moiety, for radiolabeling with the [99mTc(CO)3(H2O)3]+ precursor. The complex prepared, being lipophilic, was expected to behave as a lipiodol surrogate. The radiolabeled complex could be obtained in >95% radiochemical yield, as characterized by high-performance liquid chromatography. The intravenous injection of the radiolabeled complex in mice resulted in 23.5% +/- 4.3% uptake of injected dose (ID) organ in the liver at 3 hours postinjection. However, the uptake of the lipiodol suspension of the complex at 3 hours postinjection in the liver was found to be 43.8 +/- 13.4% ID/organ, when injected via the portal vein.

Preparation of 166Ho-oxine-lipiodol and its preliminary bioevaluation for the potential application in therapy of liver cancer

OBJECTIVE

Intra-arterial administration of beta-emitting radionuclides in the form of suitable radiopharmaceuticals is one of the promising modalities for the treatment of liver cancer. Ho [T1/2=26.9 h, Ebeta(max)=1.85 MeV, Egamma=81 keV (6.4%)] could be envisaged as an attractive radionuclide for the use in liver cancer therapy owing to its high-energy beta-emission, short half-life and feasibility of its production with adequately high specific activity and radionuclidic purity using moderate flux reactors. Lipiodol is chosen as the vehicle to deliver localized doses of ionizing radiation to liver cancer cells after intra-arterial hepatic infusion as it is selectively retained in the vascular periphery of the proliferating cells.

METHODS

Ho was produced by thermal neutron bombardment on a natural Ho2O3 target at a flux of approximately 6 x 10 n/cm.s for 7 days. Radiolabelled lipiodol was prepared by dispersing the Ho-oxine complex in lipiodol. The biological behaviour of Ho-oxine-lipiodol was studied by biodistribution and imaging studies in normal Wistar rats.

RESULTS

Ho was produced with a specific activity of 9.25-11.10 TBq/g and radionuclidic purity of approximately 100%. The Ho-labelled oxine complex was prepared in high yield (approximately 97%). Approximately, 95% of the Ho activity was dispersed in lipiodol within 30 min. The resulting radiolabelled preparation was found to exhibit good stability in physiological saline and human serum up to 3 days. The biodistribution and imaging studies revealed satisfactory hepatic retention (88.43+/-2.85% of injected activity after 2 days) with insignificant uptake in any other major organ/tissue except skeleton (6.44+/-1.07% at 2 days postinjection).

CONCLUSION

The Ho-oxine-lipiodol preparation exhibited promising features in preliminary studies and warrants further investigation.

Surface modified superparamagnetic iron oxide nanoparticles: as a new carrier for bio-magnetically targeted therapy

Amino-functionalized superparamagnetic iron oxide nanoparticles (SPION) were synthesized by coprecipitation method. The particles were characterized by X-ray diffraction (XRD), vibrating sample magnetometer (VSM), scanning electron micrographs (SEM), transmission electron micrographs (TEM) and atomic force micrographs (AFM). The size of the modified particles varied in the range 10-15 nm and did not change significantly after modification. Hepama-1, an excellent humanized monoclonal antibody directed against liver cancer, was conjugated to the SPION to prepare immuno-magnetic nanoparticles (IMN). A direct labeling method was employed to radiolabel IMN with rhenium-188. The radiolabeling efficiency was about 90% with good in vitro stability. (188)Re labeled IMN could markedly kill SMMC-7721 liver cancer cells. Such SPION might be very useful for bio-magnetically targeted radiotherapy in liver cancer treatment.

Treatment of hepatocellular carcinoma by means of radiopharmaceuticals

Several techniques have been developed for radionuclide therapy of hepatocellular carcinoma (HCC). Medical literature databases (Pubmed, Medline) were screened for available literature and articles were critically analysed as to their scientific relevance. In a palliative setting, intra-arterial administration of 131I-Lipiodol yields responses in 17-92% of patients. According to a randomised study, 131I-Lipiodol was far better tolerated than classic chemo-embolisation. The additive value of a single 131I-Lipiodol administration following partial liver resection for HCC was evaluated and evidence is available that adjuvant radionuclide treatment reduces the recurrence rate. Data concerning the role of 131I-Lipiodol in bridging patient to liver transplantation are scarce but suggest a potential benefit in terms of reducing the drop-out rate while patients are listed for transplantation. 188Re- and 90Y-labelled conjugates are emerging and initial clinical data are promising. Treatment of HCC with 90Y-labelled microspheres is likely as efficacious as treatment with radiolabelled Lipiodol but pretreatment 99mTc-MAA scintigraphy is required in order to exclude patients with significant lung shunting. Several antibodies targeting antigens expressed on HCC have been radiolabelled, almost exclusively with 131I, and evaluated in a preclinical or clinical setting. The use of radiolabelled Lipiodol and microspheres allows for selective targeting of HCC with limited toxicity. Prospective, randomised controlled trials demonstrating that both treatment modalities may provide a survival benefit in a palliative setting are mandatory. In addition, future research should focus on the complementary role of radionuclide treatment in patients at risk for recurrent disease following partial liver resection or while awaiting liver transplantation.