Estrogen receptor status in primary breast cancer: iodine 123-labeled cis-11beta-methoxy-17alpha-iodovinyl estradiol scintigraphy.

PURPOSE: To determine the sensitivity of iodine 123 ((123)I)-labeled cis-11beta-methoxy-17alpha-iodovinyl estradiol (Z-MIVE) scintigraphy for the detection of estrogen receptors in patients with primary breast carcinoma. MATERIALS AND METHODS: In 22 patients, estrogen receptor status was assessed with planar scintigraphy and single photon emission computed tomography (SPECT) 4 hours after the injection of 185 MBq (123)I-labeled Z-MIVE. For histologic and estrogen receptor immunohistochemical analysis, breast carcinoma tissue was obtained in all patients by means of biopsy or resection of the primary tumor. Two experienced physicians semiquantitatively scored the scintigraphic and immunohistochemical findings. The uptake ratio at scintigraphy and the immunohistologic staining intensity were scored as negative, weak, intermediate, or strong. RESULTS: All patients had histologically proven breast cancer. Immunohistologic staining for estrogen receptors yielded negative findings in four patients and positive findings in 18 (weak staining, n = 2; intermediate staining, n = 6; strong staining, n = 10). Planar (123)I-labeled Z-MIVE scintigraphic findings were negative in five patients and positive in 17 (weak uptake, n = 2; intermediate uptake, n = 10; strong uptake, n = 5), resulting in one false-negative finding. Findings at (123)I-labeled Z-MIVE SPECT were negative in four patients and positive in 18. The sensitivities of (123)I-labeled Z-MIVE scintigraphy for estrogen receptors were 100% with SPECT and 94% with planar scintigraphy. The correlation between immunohistologic and planar scintigraphic scores of estrogen receptor status was 0.72 (P <.01). CONCLUSION: (123)I-labeled Z-MIVE scintigraphy is a sensitive noninvasive tool for the detection of estrogen receptors in patients with breast cancer.

New iodinated progestins as potential ligands for progesterone receptor imaging in breast cancer. Part 1: Synthesis and in vitro pharmacological characterization.

Five putative iodinated progesterone receptor (PR) binding ligands were synthesized and evaluated as potential imaging agents for PR-positive human breast tumours. Two compounds (E- and Z-17-hydroxy-21-iodo-19-nor-17alpha-pregna-4,20-dien-3-one; E- and Z-IPG1) were previously described, but are re-evaluated. The other three were novel compounds: two nortestosterone analogues derived from ORG 3236 (E- and Z-13-ethyl-17-hydroxy-21-iodo-11-methylene-18,19-dinor-17alpha-pre gna-4,20-diene-3-one; E- and Z-IPG2) and one norprogesterone analogue derived from ORG 2058 (21-[4-iodophenoxy]-16alpha-ethyl-19-norpregn-4-ene-3, 20-dione; IPG3). The E-iodovinyl nortestosterone compounds were obtained by a new route of synthesis. Competitive binding studies were performed to determine their binding affinities for the PR in three types of tissue (human MCF-7 breast tumour cells and rat uterine and mammary tumour tissue) and for the androgen receptor (AR) in human MCF-7 breast tumour cells, as well as for the sex hormone-binding globulin (SHBG) and corticosteroid-binding globulin (CBG) in human plasma. All four 17alpha-iodovinyl nortestosterone derivatives displayed high binding affinity for the human PR, that of Z-IPG1 and E- and Z-IPG2 being even higher than that of ORG2058. Their affinities for the rat PR were somewhat lower, especially those of both E-isomers. The affinity of IPG3 was lower for both the human and rat PR. The nortestosterone derivatives also showed AR binding, the relative binding affinities ranging from 4.3 to 17.0% as compared with 5alphaDHT. Additionally, neither of these steroids displayed any significant binding to either SHBG or CBG in human plasma. We conclude that the in vitro binding properties of all four 17alpha-iodovinyl nortestosterone derivatives warrant evaluation of the distribution characteristics of their 123I-labelled analogues to determine their usefulness as PR imaging agents.

New iodinated progestins as potential ligands for progesterone receptor imaging in breast cancer. Part 2: In vivo pharmacological characterization.

On the basis of the observed high selective binding to both the human and rat progesterone receptor (PR) in vitro, three 17alpha-iodovinyl-substituted nortestosterone derivatives, i.e., the Z-isomer of 17alpha-iodovinyl-19-nortestosterone (Z-IVNT; Z-IPG1) and both the stereoisomers of 17alpha-iodovinyl-18-methyl-11-methylene-19-nortestosterone (E- and Z-IPG2), were selected for radio-iodination and subsequently evaluated as potential radioligands for PR imaging in human breast cancer. Their target tissue uptake, retention, and uptake selectivity were studied in female rats. The distribution studies revealed that PR-mediated uptake in the uterus and ovaries could only be demonstrated for Z-[123I]IPG2. The target tissue uptake selectivity was, however, low, with the highest uterus-to-nontarget tissue uptake ratios observed at 2-4 h postinjection (p.i.), being 4.4, 1.8, and 7.4 for the uterus-to-blood, -fat, and -muscle ratio, respectively. For Z-[123I]IPG2, distribution was also studied in dimethylbenzanthracene (DMBA)-induced mammary tumour-bearing rats and in normal rabbits. Mammary tumour uptake of Z-[123I]IPG2 in the mammary tumour-bearing rat was also found to be PR-specific. In rabbits, higher selective target tissue uptake of Z-[123I]IPG2 was observed than in rats, resulting in uterus-to-blood, -fat, and -muscle ratios of 6.6, 2.2, and 21.3 at 2-4 h p.i., respectively. In conclusion, Z-[123I]IPG2, which displayed high binding affinity for both the human and rat PR in vitro, showed specific PR-mediated target tissue uptake in rats and rabbits in vivo, the uptake selectivity being highest in the latter. Because the binding characteristics appeared to vary between species, a pilot study in breast cancer patients may be needed to decide whether Z-[123I]IPG2 can be of potential use as PR imaging agent in breast cancer.

Synthesis, estrogen receptor binding, and tissue distribution of a new iodovinylestradiol derivative (17alpha,20E)-21-[123I]Iodo-11beta-nitrato-19-norp regna-1,3,5 (10),20-tetraene-3,17-diol (E-[123I]NIVE).

We have synthesized and evaluated E-11beta-nitrato-17alpha-iodovinylestradiol (E-NIVE; E-3c) and its 123I-labelled form, as a new potential radioligand for imaging of estrogen receptor (ER)-positive human breast tumors. E-[123I]NIVE was prepared by stereospecific iododestannylation of the E-tri-n-butylstannylvinyl precursor (E-2c), obtained from reaction of 11beta-nitrato-estrone (8) with E-tributylstannylvinyllithium. In competitive binding studies, E-NIVE proved to have high binding affinity for both the rat and the human ER (Ki 280-730 pM), without significant binding to human sex hormone binding globulin. Distribution studies in normal and mammary tumor-bearing rats showed specific ER-mediated uptake of E-[123I]NIVE in the estrogen target tissues, i.e., uterus, ovaries, pituitary, and hypothalamus, but not in the mammary tumors. Selective retention in these target tissues, including tumor tissue, resulted in significant increases over time for the target tissue-to-muscle uptake ratios, but not for the target tissue-to-fat uptake ratios. The tumor-to-fat uptake ratio even appeared constantly below 1. In the primary estrogen target tissues, E-[123I]NIVE displayed high specific ER-mediated uptake and retention, which resulted in moderate target-to-nontarget tissue uptake ratios. In contrast, in tumor tissue, E-[123I]NIVE uptake appeared to be rather low and not ER-specific. As a consequence, E-[123I]NIVE appears to be a less favorable radioligand for ER imaging in breast cancer than the previously studied stereoisomers of 11beta-methoxy-17alpha-[123I]iodovinylestradiol (E- and Z-[123I]MIVE; [123I]E- and [123I]Z-3b).

Biodistribution and dosimetry of iodine-123-labelled Z-MIVE: an oestrogen receptor radioligand for breast cancer imaging.

This study reports on the distribution and radiation dosimetry of iodine-123-labelled cis-11beta-methoxy-17alpha-iodovinyloestradiol (Z-[123I]MIVE), a promising radioligand for imaging of oestrogen receptors (ERs) in human breast cancer. Whole-body scans were performed up to 24 h after intravenous injection of 138-193 MBq Z-[123I]MIVE in five healthy female volunteers, four with and one without thyroid blockade. Blood samples were taken at various times up to 24 h after injection. Urine was collected up to 24 h after injection in order to calculate renal clearance and to aid in the interpretation of whole-body clearance, including faecal excretion. Time-activity curves were generated for the thyroid, heart, brain, breasts and liver, by fitting the organ-specific geometric mean counts, obtained from regions of interest, to a multicompartmental model. The MIRD formulation, using 11 source organs, was applied to calculate the absorbed radiation doses for various organs upon administration of Z-[123I]MIVE. The images showed rapid hepatobiliary excretion which resulted in good imaging conditions for the thoracic region. Imaging of the abdominal region was impeded due to extensive bowel activity. Diffuse uptake and retention of activity was seen in breast tissue, the breast-to-non-specific uptake ratio increasing over time. Z-[123I]MIVE was cleared by both the kidneys and the gastrointestinal tract. At 50 h p.i. the mean excretion in urine was predicted to be 58%+/-14% (SD) and that in faeces 31%+/-19%. If the thyroid was not blocked, it was the most critical organ (0.33 mGy/MBq). In general, the excretory organs received the highest absorbed doses, i.e. the lower and upper large intestinal walls (0.11 and 0.098 mGy/MBq, respectively), the urinary bladder wall (0.090 mGy/MBq), the gallbladder wall (0.087 mGy/MBq) and the small intestine (0.043 mGy/MBq). The average effective dose equivalent of Z-[123I]MIVE was estimated to be 0.033 mSv/MBq. The amount of Z-[123I]MIVE required for adequate breast cancer ER imaging results in an acceptable effective dose equivalent to the patient.

[123I]FP-CIT binds to the dopamine transporter as assessed by biodistribution studies in rats and SPECT studies in MPTP-lesioned monkeys.

[123I]FP-CIT (N-omega-fluoropropyl-2 beta-carbomethoxy-3 beta-(4-iodophenyl)-tropane), a radioiodinated cocaine analogue, was evaluated as an agent for the in vivo labeling of dopamine (DA) transporters by biodistribution studies in rats and by single photon emission computed tomography (SPECT) studies in unilateral 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned monkeys. In rats, intravenous injection of [123I]FP-CIT resulted in high accumulation of radioactivity in the striatum. Less pronounced uptake was seen in brain areas with high densities of serotonergic uptake sites. While striatal uptake of radioactivity after injection of [123I]FP-CIT was displaced significantly by GBR12,909 but not by fluvoxamine, the opposite was observed in brain areas known to be rich of serotonin transporters. Monkeys which were unilaterally treated with neurotoxic doses of MPTP showed severe loss of striatal [123I]FP-CIT uptake at the side of treatment. The results of this study indicate that [123I]FP-CIT, although not being a selective radioligand, binds specifically to the striatal DA transporter in vivo and thus suggest that [123I]FP-CIT promises to be a suitable radioligand for SPECT imaging of DA transporters in humans.

Imaging of estrogen receptors in primary and metastatic breast cancer patients with iodine-123-labeled Z-MIVE.

PURPOSE: To evaluate the feasibility of noninvasive imaging of estrogen receptors (ERs) in primary and metastatic breast cancer with the iodine-123-labeled ER-specific ligand cis-11beta-methoxy-17alpha-iodovinylestradiol-17beta (Z-[123I]MIVE) using conventional nuclear medicine techniques. PATIENTS AND METHODS: Z-[123I]MIVE planar scintigraphy and single-photon emission computed tomography (SPECT) were performed in 12 patients with proven primary breast cancer and 13 patients with proven or from other imaging modalities evident bone, liver, lung, pleura and/or lymph node metastases. The results were compared with those of ER immunohistochemistry (IHC). Blocking studies with the antiestrogen tamoxifen were performed to test whether Z-[123I]MIVE tumor uptake was ER-mediated. RESULTS: Planar imaging showed uptake in 11 of 12 primary carcinomas. ER IHC performed for nine of these was positive. For the planar scintigraphy-negative patient, SPECT was faintly positive, but ER IHC negative (agreement, 90%). In nine of 13 metastatic patients, planar scintigraphy was positive. The agreement between the results of ER IHC on the original primary tumor and of Z-[123I]MIVE scintigraphy was 82%. Specificity of tumor Z-[123I]MIVE uptake was established by complete blockade of uptake by tamoxifen, except in two patients who showed progressive disease. Z-[123I]MIVE scintigraphy also enabled discriminating metastases from confounding nonmalignant abnormalities of the bone scan. CONCLUSION: Z-[123I]MIVE scintigraphy shows high sensitivity and specificity for the detection of ER-positive breast cancer. This may have impact on diagnostic possibilities and therapeutic management. Since ER imaging shows the functional status, addressing known intratumoral and intertumoral ER heterogeneity, it may improve the characterization of disease and the selection of patients who may benefit from hormonal therapy.

The Z-isomer of 11 beta-methoxy-17 alpha-[123I]iodovinylestradiol is a promising radioligand for estrogen receptor imaging in human breast cancer.

The potential of both stereoisomers of 11 beta-methoxy-17 alpha-[123I] iodovinylestradiol (E- and Z-[123I]MIVE) as suitable radioligands for imaging of estrogen receptor (ER)-positive human breast tumours was studied. The 17 alpha-[123I]iodovinylestradiol derivatives were prepared stereospecifically by oxidative radioiododestannylation of the corresponding 17 alpha-tri-n-butylstannylvinylestradiol precursors. Both isomers of MIVE showed high in vitro affinity for dimethylbenzanthracene-induced rat and fresh human mammary tumour ER, that of Z-MIVE however being manyfold higher than that of E-MIVE. In vivo distribution studies with E- and Z-[123I]MIVE in normal and tumour-bearing female rats showed ER-mediated uptake and retention in uterus, ovaries, pituitary, hypothalamus and mammary tumours, again the highest for Z-[123I]MIVE. The uterus- and tumour-to-nontarget tissue (far, muscle) uptake ratios were also highest for Z-[123I]MIVE. Additionally, planar whole body imaging of two breast cancer patients 1-2 h after injection of Z-[123I]MIVE showed increased focal uptake at known tumour sites. Therefore, we conclude that Z-[123I]MIVE is a promising radioligand for the diagnostic imaging of ER in human breast cancer.

Generation of HER-2/neu-specific cytotoxic neutrophils in vivo: efficient arming of neutrophils by combined administration of granulocyte colony-stimulating factor and Fcgamma receptor I bispecific antibodies.

Abs are able to induce inflammatory antitumor responses by recruiting IgG Fc receptor (FcgammaR)-bearing cytotoxic effector cells. We recently described the capacity of the high affinity FcgammaRI (CD64) to trigger cytotoxic activity of neutrophils (PMN) during granulocyte CSF (G-CSF) treatment. To take advantage of FcgammaRI as a cytotoxic trigger molecule on PMN, two Ab constructs were prepared. We show that a chimeric human IgG1 Ab (Ch520C9) and an anti-FcgammaRI bispecific Ab (BsAb; 22x520C9), both directed to the proto-oncogene product HER-2/neu, interact with FcgammaRI. In addition, both Ab constructs mediate enhanced lysis of HER-2/neu-expressing tumor cells by G-CSF-primed PMN. However, engagement of FcgammaRI by Ch520C9 was inhibited by human serum IgG, thereby abrogating the enhanced Ch520C9-mediated cytotoxicity. BsAb 22x520C9, which binds FcgammaRI outside the ligand binding domain, effectively recruits the cytotoxic potential of FcgammaRI on G-CSF-primed PMN regardless of the presence of human serum. These results indicate that under physiologic conditions, serum IgG impairs activation of FcgammaRI-mediated cytotoxicity by conventional antitumor Abs. The IgG blockade can be circumvented with anti-FcgammaRI BsAbs. Using human FcgammaRI transgenic mice we demonstrate that BsAb 22x520C9 is able to engage FcgammaRI in vivo. BsAb 22x520C9 injected i.v. was readily detected on circulating PMN of G-CSF-treated transgenic animals. In addition, we showed that PMN remain "armed" with BsAb 22x520C9 during migration to inflammatory sites, and that after isolation such PMN specifically lyse HER-2/neu-expressing tumor cells. These results point to the possibility of targeting anti-FcgammaRI BsAbs to G-CSF-primed PMN in vivo, endowing them with specific anti-tumor activity.

In vitro and in vivo characterization of newly developed iodinated 1-[2-[bis(4-fluorophenyl)methoxy]ethyl]piperazine derivatives in rats: limited value as dopamine transporter SPECT ligands.

A series of 1-{2-[bis(4-fluorophenyl)methoxy]ethyl}piperazines (CYD1, 2, 3, 5) with a 4-substituent incorporating a 1-hydroxy-3-iodo-2-propenyl moiety, except CYD2 which lacks the hydroxy, was synthesized as potential in vivo imaging ligands for the dopamine transporter. For two of the piperazine derivatives (CYD3 and 5), possible stereoselectivity was considered as well (both E- and Z-form). Their in vitro potency for inhibition of [3H]dopamine uptake in rat striatal synaptosomes was 10-fold lower than that of GBR 12,909 used as a reference. The highest Ki values were 137 and 101 nM for CYD1E and CYD3E, respectively. Inhibition potency was higher for the E- than for the Z-isomers. In vivo distribution of radioactivity in rats injected with the 123I-labeled CYDs showed preferred striatal uptake for CYD1E and CYD3E as compared to the cerebellum and occipital cortex. Although the E-isomer of CYD3 showed the best in vitro and in vivo binding characteristics, its striatal uptake ratios (maximal value: 2.7 for striatum-to-cerebellum at 4 h p.i.) are too low to consider application in human Single Photon Emission Computed Tomography studies.

The stereoisomers of 17alpha-[123I]iodovinyloestradiol and its 11beta-methoxy derivative evaluated for their oestrogen receptor binding in human MCF-7 cells and rat uterus, and their distribution in immature rats.

We studied the potential of both stereoisomers of 17alpha-[123I]iodovinyloestradiol (E- and Z-[123I]IVE) and of 11beta-methoxy-17alpha-[123I]iodovinyloestradiol (E- and Z-[123I]MIVE) as suitable radioligands for the imaging of oestrogen receptor(ER)-positive human breast tumours. The 17alpha-[123I]iodovinyloestradiols were prepared stereospecifically by oxidative radio-iododestannylation of the corresponding 17alpha-tri-n-butylstannylvinyloestradiol precursors. Competitive binding studies were performed in order to determine the relative binding affinity (RBA) of the unlabelled 17alpha-iodovinyloestradiols for the ER in both human MCF-7 breast tumour cells and rat uterine tissue, compared with that of diethylstilboestrol (DES). Target tissue uptake, retention and uptake selectivity of their 123I-labelled analogues were studied in immature female rats. All four 17alpha-iodovinyloestradiols showed high affinity for the ER in human MCF-7 cells, as well as rat uterus. Their RBA for the ER showed the following order of decreasing potency: RBA of DES >Z-IVE >Z-MIVE >E-MIVE > or =E-IVE. Neither of these 17alpha-iodovinyloestradiols showed any significant binding to the sex hormone binding globulin in human plasma. The biodistribution studies showed ER-mediated uptake in the uterus, ovaries and pituitary, that of E- and Z-[123I]MIVE being higher than that of E- and Z-[123I]IVE. High target-to-non-target tissue uptake ratios, especially at longer periods after injection (up to 24h), were exhibited by both isomers of [123I]MIVE. The uterus-to-blood uptake ratio was higher for E-[123I]MIVE. However, the uterus-to-fat uptake ratio appeared to be higher for the Z-isomer of [123I]MIVE, especially at 24h after injection. Metabolic properties and temperature effects, which play a more important role in vivo, probably cause the discrepancies seen between in vitro and in vivo binding results. On the basis of their in vitro binding properties and in vivo distribution characteristics we conclude that E- and Z-[123I]MIVE could be suitable radioligands for the diagnostic imaging of ER in human breast cancer. Therefore, further studies with these radioligands in mature normal and tumour-bearing rats are warranted.