Effects of theophylline on radioiodide uptake in MCF-7 breast cancer and NIS gene-transduced SNU-C5 colon cancer cells

Zr-89 Immuno-PET Targeting Ectopic ATP Synthase Enables In-Vivo Imaging of Tumor Angiogenesis

In this study, we synthesized a Zr-89-labeled anti-adenosine triphosphate synthase monoclonal antibody (ATPS mAb) for applications in immuno-positron emission tomography (PET) and evaluated its feasibility for angiogenesis imaging. The cellular uptake of Zr-89 ATPS mAb was measured after treatment of cancer cell lines in vitro, and its biodistribution was evaluated at 4, 24 and 48 h in vivo in mice bearing xenografts. PET images were acquired at 4, 24, 48, and 96 h after Zr-89 ATPS mAb administration. Tumor angiogenesis was analyzed using anti-CD31 immunofluorescence staining. The cellular uptake of Zr-89 ATPS mAb increased over time in MDA-MB-231 breast cancer cells but did not increase in PC3 prostate cancer cells. The tumor uptake of Zr-89 ATPS mAb at 24 h was 9.4 ± 0.9% ID/g for MDA-Mb-231 cells and was 3.8 ± 0.6% ID/g for PC3 cells (p = 0.004). Zr-89 ATPS mAb uptake in MDA-MB-231 xenografts was inhibited by the administration of cold ATPS mAb (4.4 ± 0.5% ID/g, p = 0.011). Zr-89 ATPS mAb uptake could be visualized by PET for up to 96 h in MDA-MB-231 tumors. In contrast, there was no distinct tumor uptake detected by PET in the PC3 xenograft model. CD31-positive tumor vessels were abundant in MDA-MB-231 tumors, whereas they were scarcely detected in PC3 tumors. In conclusion, ATPS mAb was successfully labeled with Zr-89, which could be used for immuno-PET imaging targeting tumor angiogenesis.

Correlation among ocular surface disease, xerostomia, and nasal symptoms in patients with differentiated thyroid carcinoma subjected to radioiodine therapy: A prospective comparative study

BACKGROUND

Some complications of radioiodine therapy have been reported, but the involvement of the eyes and adnexa is rarely discussed. The purpose of this study was to determine the correlation among ocular surface changes, xerostomia, and changes in the nasal mucosa associated with radioiodine therapy.

METHODS

Patients subjected to radioiodine therapy (group 1) or not subjected (group 2) were prospectively evaluated by examinations of the ocular surface and tear film, saliva production, and nasal endoscopy. Ocular and nasal symptoms and xerostomia were evaluated using questionnaires.

RESULTS

Evaluation of the ocular surface did not indicate significant differences between the groups. Nasal endoscopy revealed higher mucosal pallor in group 1 and worsening of the endoscopic appearance. Worsening of ocular symptoms and nasal symptoms, xerostomia, and a significant decrease in salivary production was also observed in group 1.

CONCLUSION

Subjective worsening of xerostomia, xerophthalmia, nasal symptoms, and changes in the nasal mucosa in group 1 was observed.

Lacrimal System Obstruction After Radioiodine Therapy in Differentiated Thyroid Carcinomas: A Prospective Comparative Study

BACKGROUND

Radioiodine therapy (RIT) is an established treatment for differentiated thyroid carcinomas, and is widely used throughout the world, given the increasing incidence of this malignancy. Although serious adverse effects are infrequent, complications such as dry mouth, sialadenitis, and dysphagia have been described. The involvement of the eyes and accessory visual structures is not commonly discussed, despite dry eye, keratoconjunctivitis, and lacrimal system obstruction (LSO) being reported, especially after high cumulative doses of radiopharmaceuticals. The incidence of LSO is not well established.

OBJECTIVES

The aim of this study was to determine the frequency of LSO in patients undergoing RIT at 2, 4, 6, and 12 months after treatment.

METHODS

Patients with differentiated thyroid carcinoma undergoing (group 1) and not undergoing (group 2) RIT were evaluated in the preoperative and postoperative periods and 2, 4, 6, and 12 months post surgery or post RIT. Patients underwent tear film evaluation and lacrimal system probing and irrigation.

RESULTS

Group 1 (n = 44; 88 eyes) contained three patients (four eyes) with LSO, corresponding to an incidence of 4.55% (four events in 88 eyes) or 6.8% (three cases in 44 patients). Group 2 (n = 43; 86 eyes) did not present any cases of LSO.

CONCLUSIONS

In this study, an active prospective investigation allowed LSO detection during the first six months after RIT. This finding demonstrates the importance of making this association clear to patients and health professionals, with a view to early diagnosis, appropriate treatment, and preventing LSO-related complications.

Sodium iodide symporter (NIS) in extrathyroidal malignancies: focus on breast and urological cancer

Background

Expression and function of sodium iodide symporter (NIS) is requisite for efficient iodide transport in thyrocytes, and its presence in cancer cells allows the use of radioiodine as a diagnostic and therapeutic tool in thyroid neoplasia. Discovery of NIS expression in extrathyroidal tissues, including transformed cells, has opened a novel field of research regarding NIS-expressing extrathyroidal neoplasia. Indeed, expression of NIS may be used as a biomarker for diagnostic, prognostic, and therapeutic purposes. Moreover, stimulation of endogenous NIS expression may permit the radioiodine treatment of extrathyroidal lesions by concentrating this radioisotope.

Results

This review describes recent findings in NIS research in extrathyroidal malignancies, focusing on breast and urological cancer, emphasizing the most relevant developments that may have clinical impact.

Conclusions

Given the recent progress in the study of NIS regulation as molecular basis for new therapeutic approaches in extrathyroidal cancers, particular attention is given to studies regarding the relationship between NIS and clinical-pathological aspects of the tumors and the regulation of NIS expression in the experimental models.

The sodium iodide symporter (NIS): regulation and approaches to targeting for cancer therapeutics

Expression of the sodium iodide symporter (NIS) is required for efficient iodide uptake in thyroid and lactating breast. Since most differentiated thyroid cancer expresses NIS, β-emitting radioactive iodide is routinely utilized to target remnant thyroid cancer and metastasis after total thyroidectomy. Stimulation of NIS expression by high levels of thyroid-stimulating hormone is necessary to achieve radioiodide uptake into thyroid cancer that is sufficient for therapy. The majority of breast cancer also expresses NIS, but at a low level insufficient for radioiodine therapy. Retinoic acid is a potent NIS inducer in some breast cancer cells. NIS is also modestly expressed in some non-thyroidal tissues, including salivary glands, lacrimal glands and stomach. Selective induction of iodide uptake is required to target tumors with radioiodide. Iodide uptake in mammalian cells is dependent on the level of NIS gene expression, but also successful translocation of NIS to the cell membrane and correct insertion. The regulatory mechanisms of NIS expression and membrane insertion are regulated by signal transduction pathways that differ by tissue. Differential regulation of NIS confers selective induction of functional NIS in thyroid cancer cells, as well as some breast cancer cells, leading to more efficient radioiodide therapy for thyroid cancer and a new strategy for breast cancer therapy. The potential for systemic radioiodide treatment of a range of other cancers, that do not express endogenous NIS, has been demonstrated in models with tumor-selective introduction of exogenous NIS.