Multimodal somatostatin receptor theranostics using [64Cu]Cu-/[177Lu]Lu-DOTA-(Tyr3)octreotate and AN-238 in a mouse pheochromocytoma model

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

Abstract

Pheochromocytomas and extra-adrenal paragangliomas (PHEO/PGLs) are rare catecholamineproducing chromaffin cell tumors. For metastatic disease, no effective therapy is available. Overexpression of somatostatin type 2 receptors (SSTR2) in PHEO/PGLs promotes interest in applying therapies using somatostatin analogs linked to radionuclides and/or cytotoxic compounds, such as [177Lu]Lu-DOTA-(Tyr3)octreotate (DOTATATE) and AN-238. Systematic evaluation of such therapies for the treatment of PHEO/PGLs requires sophisticated animal models. In this study, the mouse pheochromocytoma (MPC)-mCherry allograft model showed high tumor densities of murine SSTR2 (mSSTR2) and high tumor uptake of [64Cu]Cu-DOTATATE. Using tumor sections, we assessed mSSTR2-specific binding of DOTATATE, AN-238, and somatostatin-14. Therapeutic studies showed substantial reduction of tumor growth and tumor-related renal monoamine excretion in tumor-bearing mice after treatment with [177Lu]Lu-DOTATATE compared to AN-238 and doxorubicin. Analyses did not show agonist-dependent receptor downregulation after single mSSTR2-targeting therapies. This study demonstrates that the MPC-mCherry model is a uniquely powerful tool for the preclinical evaluation of SSTR2-targeting theranostic applications in vivo. Our findings highlight the therapeutic potential of somatostatin analogs, especially of [177Lu]Lu-DOTATATE, for the treatment of metastatic PHEO/PGLs. Repeated treatment cycles, fractionated combinations of SSTR2-targeting radionuclide and cytotoxic therapies, and other adjuvant compounds addressing additional mechanisms may further enhance therapeutic outcome.

Details

Original languageEnglish
Pages (from-to)650-665
Number of pages16
JournalTheranostics
Volume6
Issue number5
Publication statusPublished - 10 Mar 2016
Peer-reviewedYes

External IDs

PubMed 27022413

Keywords

Keywords

  • Catecholamines, DOTATATE, Doxorubicin, Metanephrines, Neuroendocrine tumors, Optical in vivo imaging, PET, SPECT