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Molecular Oncology, Markers, Clinical Correlates |
Pediatric Surgical Research Laboratories and Pediatric Surgical Services, Department of Surgery [P. T. M., D. T. M., J. T., S. M., P. C. S., D. J. K., M. K. K., T. U. H., and P. K. D.], Gynecologic Oncology, Department of Obstetrics and Gynecology [A. F. F.], and Flow Cytometry Laboratory, Department of Pathology [D. M. D., F. I. P.], The Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114
| ABSTRACT |
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2 analysis (P = 0.025). Solid ovarian cancers were positive for the MIS type II receptor protein by immunohistochemical staining, which colocalized with staining for antibody to CA-125 (OC-125). Thus, the detection of the MIS type II receptor by flow cytometry may be a useful predictor of therapeutic response to MIS and may be a modality to rapidly choose patients with late-stage ovarian cancer for treatment with MIS. | INTRODUCTION |
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MIS signals through a heteromeric receptor, one partner of which is the MIS type II receptor, which was found to share homology with the TGF-
and activin type II receptors (15, 16, 17, 18)
as a conserved single transmembrane serine/threonine kinase. As with other members of the TGF-
family of receptors, the MIS type II receptor is assumed to form a complex with a type I receptor that, as a class, are homologous to type II receptors in the kinase domain (19)
. In this complex, the type II receptor renders specificity by selective ligand binding, and phosphorylation of the type I receptors by the type II receptors initiates downstream signaling. In situ hybridization shows that MIS type II receptor mRNA is developmentally expressed in the urogenital ridges of both sexes in the epithelium and mesenchyme of the Mullerian duct, on the coelomic epithelium, and in the tubules of embryonic gonads (15
, 16
, 18)
. Northern analysis of a variety of tissues shows high expression of the MIS type II receptor in the gonads, urogenital ridge, and uterus (18)
. Inactivation of MIS (20)
or its type II receptor (21)
by homologous recombination results in males with retained Mullerian ducts, Leydig cell hyperplasia, and Leydig cell tumors. In female transgenic mice, overexpression of MIS results in regression of the Mullerian ducts in the embryo and complete ablation of the ovaries in the adult (22)
, suggesting that the ovaries could be a target for MIS action and express MIS receptors. To investigate this possibility, we examined ovarian cancer cell lines and primary human ovarian cancer ascites cells using tools and probes developed in this laboratory. We scaled up production of rhMIS, successfully labeled it with biotin for binding studies, cloned the human MIS type II receptor for mRNA detection, and raised antibodies to the type II receptor for protein detection. After careful validation, we found that the cell lines and primary ascites cells that functionally responded to MIS by inhibition of growth express the MIS type II receptor and bind MIS. These results suggest that human ovarian cancers may be therapeutic targets for MIS.
| MATERIALS AND METHODS |
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Study Subjects.
Ascites from 27 patients, who ranged in age from 21 to 91 years (mean, 61 years) with stage III or IV ovarian cystadenocarcinoma, were studied, and all but four were postmenopausal. The study was approved by the Subcommittee on Human Studies of Massachusetts General Hospital, and consent was obtained from each patient in our Gynecological Oncology Service.
Purification of Bioactive rhMIS and a Bioinactive Mutant (L9).
Wild-type rhMIS or the mutant MIS (L9) was purified by immunoaffinity chromatography from MIS gene-transfected Chinese hamster ovary cells as described (23, 24, 25)
. The protein was quantified by the Bradford assay (26)
, and its bioactivity was measured in the MIS-specific fetal rat organ culture bioassay (27)
. L9 is not biologically active (28)
and is the negative protein control for active ligand. The Massachusetts General Hospital Institutional Animal Care and Use Committee approved all animal studies.
Nonadherent Colony Growth of Ascites Cells and Ovarian Cancer Cell Lines in Semisolid Media.
All of the human ovarian cancer cell lines, the negative control COS cells, and ovarian cancer ascites cells were cultured in agar as a semisolid support in 30-mm-grid dishes in quadruplicate using a method described previously (29
, 30)
in which OVCAR3 (31)
had been shown to be responsive and SKOV3 to be unresponsive to MIS (32)
to test whether MIS can inhibit their growth. The number of cells plated in these studies varied from 10,000 to 50,000 for the cell lines to 125,000 to 250,000 for the ascites samples. Increasing doses of MIS from 3.5 to 107 nM, the inactive preparation (L9) at 71 nM, or vehicle control were added to the cells. Seven to 14 days after plating, colonies measuring >4 µm in diameter and only those in the mid-cruciate pattern of 81 squares (to prevent edge effects) were counted.
Adherent Colony Growth of Ovarian Cancer Cell Lines Transfected with MIS.
OVCAR8 and IGROV-1 were also grown as colonies on a solid plastic support, after stable cotransfection with a plasmid conferring drug resistance (hygromycin), and either vector DNA or an MIS construct cloned into pcDNA 3.1(+) (Invitrogen, Carlsbad, CA) vectors. Transfected cells were grown in hygromycin for 2 weeks and stained with crystal violet to measure colony growth and MIS secreted into the media measured by a specific ELISA (3)
. The MIS construct used in this assay was the readily cleavable MIS-RR bioactive isoform generated in this laboratory (33)
. A mutant MIS that lacks the leader sequence, and thus cannot be secreted, was used as a negative control.
Construction and Screening of a Human Fetal Testis Library for the MIS Type II Receptor.
A human fetal testis cDNA library was prepared in lambda UniZap II (Stratagene, La Jolla, CA). Total RNA was extracted from the testes of fetuses, 1722 weeks of age, by homogenization as described (34)
, from which mRNA was purified using the PolyAtract system (Promega Corp., Madison, WI). cDNA sized from 1 to 5 kb was ligated into UniZap XR vector arms and packaged with GigaPack Gold generating >5 x 106 independent clones, of which 1.5 x 106 were amplified.
Screening was done by hybridization (34) with a radiolabeled fragment generated by PCR using conserved type II receptor-specific primers (17) at 42°C in 50% formamide with 2.4 x 106 clones on replicate nitrocellulose filters. Two overlapping human type II receptor cDNAs in pBluescript were excised from lambda phage clones, combined, sequenced (35) , and deposited in GenBank with accession number AF172932.
Analysis of Primary Ascites Cells from Ovarian Cancer Patients.
Ascites was obtained from 27 patients undergoing laparotomy or ultrasound-guided paracentesis. The fluid was placed on ice and centrifuged to isolate the cellular component that was resuspended in media (CMRL-1066). Hypotonic lysis and sedimentation were used to remove erythrocytes. Cells were counted using a Coulter counter and aliquoted for analysis of MIS binding, detection of the type II receptor mRNA by RT-PCR, and assessment of colony growth in soft agarose with or without MIS. Whenever sufficient cells (7 x 106) were available, flow cytometric analysis of ascites included staining for epithelial tumor and/or mesothelial cell populations (cytokeratin; Becton Dickinson, San Jose, CA) or CA-125 (using OC-125 antibody) and for hematogenous cells (using anti-CD3 or CD45 antibodies). In each MIS binding study, the hematogenous population served as an internal negative control, whereas cyto-keratin identified the epithelial population, which should contain the tumor cells and was present in all of the 27 patients samples tested. If fresh ascites was available within 4 h of collection, an aliquot of cells (108) was placed in guanidinium thiocyanate for RT-PCR using primer sets that spanned the extracellular domain of the MIS type II receptor. If the collection provided additional cells (7 x 106), cells were plated in soft agarose in quadruplicate at 250,000 cells/plate to examine colony growth in the presence or absence of rhMIS.
PCR Amplification of MIS Type II Receptor from Ovarian Cancer Cell Lines and Patient Ascites Cells.
Total cellular RNA was isolated using guanidine hydrochloride/SDS or guanidinium thiocyanate from human ovarian cancer cell lines OV1063, OVCAR3, and OVCAR5, patient ascites cells, the monkey kidney cell line COS-1, and from testis of a 15-year-old child. cDNA synthesis was carried out at 42°C using random hexamers, deoxynucleotide triphosphates, RNasin, and Superscript II reverse transcriptase (Life Technologies, Inc., Long Island, NY). PCR amplification of the entire MIS type II receptor in ovarian cancer cell lines was carried out for 30 cycles out using type II receptor specific primers (sense, 5'-CCTCCAGCAAGATGCTAGGGTCT-3' at the beginning of exon 1; and antisense, 5'-CTGCATATTTACACAGGAGAA-3' at the end of exon 11) and the PCR products analyzed on a 1% agarose gels. To determine whether the PCR fragment was identical to the MIS type II receptor, DNA was analyzed by a modified Southern analysis (34)
using a radiolabeled 32P-random primed cDNA probe specific for human MIS type II receptor. The blot was prehybridized for 4 h at 42°C with a solution containing 50% formamide, 1 M NaCl, 0.5% SDS, 50 mM Tris (pH 7.5), and 100 µg/ml salmon sperm DNA. PCR to detect exons 2 through 6 of MIS type II receptor (17)
in ascites cells was performed using MIS type II receptor-specific primers labeled 1 and 4 as follows: 1 is at the 5' end of exon 2 (5'- TTCTTTGAGGCCCCTGGAGTG-3'); and 4 is at the 3' end of exon 6 (5'-GTCGT-GCTGTAGGCCTGGAAG-3'). Shorter fragments encompassing exons 2, 3, and 4 were detected by combining primer 1 with primer 3 at the 3' end of exon 4 (5'-CACCAGTGCCATCCAGATGGA-3'). Exons 4, 5, and 6 could be observed by combining primer 2 at the beginning of the exon (5'-TCCATCTGGATGGCACTGGTG-3') with primer 4 for the PCR reactions. All of these primers and those used for human cytokeratin 8 (forward, CTGGACATGGACAGCATCATT; and backward, ACCCGCATAGCCGCCGGTGGT) and cytokeratin 18 (forward, GGCATGGGGTCCGGGGGCCTG; and backward, GCCTTTTACTTCCTCTTCGTG) were synthesized by the Massachusetts General Hospital Molecular Biology Core Laboratory.
Northern Analysis of Ovarian Cancer Cell Lines Using a Human MIS Type II Receptor Probe.
Total RNA was isolated from all of the ovarian cancer cell lines and COS cells using RNA-Stat 60 according to the instructions provided by the manufacturer (Tel Test, Friendswood, TX). Poly(A)+ RNA selection was done using FastTrack 2.0 mRNA isolation kit (Invitrogen, Carlsbad, CA), according to the protocol provided, and 34 µg of poly(A)+ RNA were separated on a 1% agarose gel and transferred onto Nytran membrane. The blot was probed with radiolabeled human MIS type II receptor cDNA.
Preparation of an MIS Type II Receptor Extracellular Domain Antibody.
Two antibodies were developed against a keyhole limpet hemocyanin-conjugated synthetic type II receptor peptide of the rat receptor (from amino acids 111127, C-G-T-D-F-C-N-A-N-Y-S-H-L-P-P-S-G), which differs from the human type II receptor by only one amino acid (P to S). Bold S denotes which of the two in the sequence differs between rat and human receptors. This unique sequence was selected from the extracellular region of the type II receptor near the transmembrane domain because of its favorable antigenicity profile (MacVector 5.0; Oxford Molecular, Campbell, CA). One antibody was raised in chickens (Covance, Denver, PA), and the IgY fraction was purified with Eggstract (Promega). Another antibody was raised in a rabbit and purified with protein A-Sepharose. Specificity of the antibodies to their cognate peptide was documented by dot blot analysis and immunohistochemical staining (1:100 dilution of primary antibody) of the 15
-day male and female embryonic urogenital ridge (36
, 37)
and to liver, stomach, pancreas, lung, and small intestine as negative control tissues using methods described earlier. Staining was also tested in four different primary human ovarian tumors. The secondary donkey antichicken or antirabbit antibody conjugated to horseradish peroxidase was purchased from Vector Labs (Burlingame, CA).
Western Analysis and Flow Cytometry to Detect MIS Type II Receptor in Transfected Cells and Cancer Cell Lines.
To validate the specificity of the chick MIS type II receptor antibody, the MIS type II receptor was overexpressed in COS cells after transfection with a pCMV-6 fusion construct containing the wild-type MIS type II receptor (pCMV-6-MISrII). To prepare lysates, cells were washed once in cold PBS, scraped off the plate, and centrifuged at 400 x g for 5 min at 4°C. The pellet was resuspended in 50 µl of RIPA [150 mM NaCl, 50 mM Tris-HCl (pH 7.4), 1% deoxycholate, and 0.1% SDS] lysis buffer, and protein concentration was determined by Bradford analysis (26)
. One hundred µg of protein were reduced with
-mercaptoethanol, separated on 10% SDS polyacrylamide gels, and transferred to nitrocellulose. The blots were blocked with 10% w/v Carnation instant milk, incubated with 1:500- to 1:1000-fold dilutions of chicken or rabbit anti-MIS type II receptor antibody or preimmune serum for 2 h, and washed prior to the addition of a 1:1000 to 1: 3000 dilution of the species-specific reporter antibody conjugated to horseradish peroxidase. Reactive protein bands were detected using ECL. In addition, an expression construct (pCMV-8/MISrII) was made with a Flag tag ("DYKDDDDK") at the NH2 terminus of the rat MIS type II receptor. This epitope was recognized by a 1:2000 dilution of the mouse monoclonal antibody M2 (Anti-Flag M2; Eastman Kodak, St. Louis, MO). Endogenous MIS type II receptor protein in OVCAR3, OVCAR5, OVCAR8, and IGROV-1 cells was detected by Western analyses in essentially the same manner as the overexpressed cloned protein, except that Immobilon membranes were used and blocking was done with 30% milk. Untransfected COS cells were negative controls. Parallel blots were incubated with anti-receptor antibody preincubated with a 2-fold excess of the peptide antigen overnight. For detection of expressed receptor by flow cytometry, transfected cells were incubated with either the chicken MIS type II receptor antibody or the mouse IgG anti-Flag antibody, and the complexes were detected with either an antimouse or antichick FITC IgG conjugate (both detected at 520 nm).
Biotinylation of rhMIS.
rhMIS was conjugated with biotin using a 40-fold molar excess NHS-LC biotin (Pierce) in PBS on ice for 30 min at neutral pH. Unreacted biotin was quenched with 100 mM Tris, and MIS-biotin was separated from unconjugated MIS using an avidin affinity column (Ultralink; Pierce). Elution fractions were analyzed for total protein (26)
prior to bioassay and Western analyses, and the degree of biotinylation of MIS was measured as described earlier (38)
. No difference in biological activity of MIS was observed when results of 33 assays with MIS-biotin were compared with 133 assays of unconjugated protein at doses of 1, 2, 3, 4, and 5 µg/ml. Avidin affinity chromatography, therefore, essentially eliminated the possibility that bioactive, nonbiotinylated rhMIS was contaminating the MIS-biotin preparations. The labeled MIS was then used to detect binding, first to MIS-sensitive cell lines, and subsequently to ascites cells harvested from patients with advanced ovarian cancer.
rhMIS Binding Assay on Ovarian Cancer Cell Lines and Ascites Cells.
OVCAR5 cells were cell cycle synchronized by four consecutive passages and after reaching 8090% confluency were grown in suspension culture and were harvested by centrifugation at 3- to 5-day intervals. The cell pellet was resuspended in binding buffer (0.5% BSA, 150 mM NaCl, 10 mM MgCl2, 10 mM KCl, and 20 mM HEPES, pH 7.4) at 106 cells/ml. OVCAR8, IGROV-1, SKOV3, and COS cells grown in monolayer were harvested by incubation with trypsin-EDTA, centrifuged, and resuspended in binding buffer at 106 cells/ml. MIS-biotin was added to cells, with or without excess unconjugated MIS, and incubated for 2 h at 4°C to avoid receptor internalization. Multiple replicates for 12 serial dilutions of MIS-biotin were used in each experiment. COS cells, which do not express MIS type II receptor, were used as a negative control. The samples were washed and resuspended in PBS, and 7 µg of avidin phycoerythrin and 10 µg of anti-cytokeratin-IgG FITC or OC-125 and mouse-anti-human-IgG-FITC were added for 30 min in the dark, on ice. The samples were washed, resuspended in PBS, and analyzed by flow cytometry with a Becton Dickinson FACScan flow cytometer (488 nm for excitation, and detection at 585 nm ± 20). Propidium iodine-positive (dead cells) were assessed in a separate aliquot and excluded from these analyses. The LYSIS software (Becton Dickinson) generated a frequency of distribution histogram of cell number versus fluorescence/cell. The arithmetic mean fluorescence/cell was plotted against concentration of MIS-biotin added to generate binding curves. The concentration of MIS-Biotin needed to reach 50% saturation of binding sites is the dissociation constant of the MIS-receptor complex. Nonspecific binding of rhMIS biotin is that remaining in the presence of 750 nM unbiotinylated rhMIS. Nonspecific binding is subtracted from total binding to estimate specific binding levels.
MIS biotin binding assays on ascites cells were done in the same manner as the cell lines, except that erythrocytes were hypotonically lysed prior to the assays; binding incubations were for 12 h at 4°C, and up to six serial dilutions of MIS-biotin were used.
Statistical Considerations.
The sensitivity of MIS flow cytometry MIS binding assays on ascites cells, defined as the ability to detect the receptor when the message is also detected by PCR, was determined by comparing the results of the two techniques using a 2 x 2 contingency table. Specificity of binding, or the ability to detect the absence of receptor, was determined in the same manner. If PCR is used as the predictor of MIS type II receptor expression, the predictive value for the MIS binding in detecting the receptor mRNA was calculated by determining the total number of patients in which both binding and mRNA were detected (n = 8), divided by total number of positive PCR results (n = 10). Correlation between the tests, binding, RT-PCR, and colony inhibition assays was tested by
2 analysis. Because the replicate experiments could be done on the cell lines, Students t test was used to determine statistical significance.
| RESULTS |
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2 analysis, there was a statistically significant correlation between MIS binding and expression of the MIS type II receptor mRNA (P = 0.025). Alternatively, there is 67% agreement among the receptor-negative cases (four of six tested), i.e., no binding correlates with no detection of receptor mRNA.
Detection of MIS Type II Receptor Protein Using the Anti-MIS Type II Receptor Antibodies.
Chicken and rabbit MIS type II receptor antibodies were developed to the peptide sequence from the extracellular juxtamembrane domain of the rat type II receptor (15
, 18)
to confirm the presence of the MIS type II receptor protein on the surface of the cells that respond to MIS and express the receptor mRNA. This peptide sequence is not present in the type I (19)
or type II receptors of other members of the TGF-
family (40
, 41) and was identified by its cognate antibody by dot blot analysis (not shown). To validate the antibody, we showed that the chick antireceptor antibody recognizes, by flow cytometric analysis, the receptor on the surface of COS cells transfected with the receptor gene but does not bind to nontransfected COS cells. The transfected receptor gene was also Flag tagged at its NH2 terminus. The fact that these cells also were identified with an NH2 terminal Flag antibody indicates that the complete extracellular domain of the protein was expressed. Western analysis of transfected COS cell extracts also showed a Mr 65,000 protein, the expected size for the MIS type II receptor (not shown). A similar Mr 65,000 band, presumed to be the endogenously expressed MIS type II receptor, was seen in the Western analyses of protein lysates of OVCAR3 using the chicken antibody (not shown). Adsorption of the chicken antibody with the original peptide antigen prevents receptor detection by Western analysis that was observed in lysates of IGROV-1 (Fig. 3A)
or OVCAR5 (Fig. 3B)
. A similar Mr 65,000 band, not present in preimmune serum, was detected in OVCAR8 using the rabbit antibody (Fig. 3C)
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-day postcoitum male rat urogenital ridge (Fig. 4A)
-day rat embryo when preimmune IgY or the chick antibody preadsorbed to its antigen was used (Fig. 4B)
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The results in aggregate show that ovarian cancer cell lines that express MIS type II receptor mRNA or protein respond to MIS in functional assays. Similarly, primary ovarian cancer ascites cells that express MIS type II receptor mRNA or protein also respond to MIS in functional assays.
| DISCUSSION |
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Expression of the MIS type II receptor was demonstrated, at the transcriptional and translational level, in a series of human ovarian cancer cell lines that are inhibited by MIS in both semisolid and adherent colony antiproliferative assays. In addition, using biotin-labeled MIS that retains biological activity, we have demonstrated binding that is specific, saturable, and of high affinity in the cell lines that were most responsive to MIS. These experimental findings using cell lines derived from human ovarian cancers that originate from the coelomic epithelium provide the first evidence that the type II receptor is present in cell lines that are growth inhibited by MIS, suggesting that the MIS effect occurs as a result of a specific receptor-mediated process rather than from random toxicity. SKOV3, the ovarian cancer cell line that was not inhibited by MIS also failed to bind MIS. Despite expressing the native MIS type II receptor as determined by Northern analysis, this cell line, however, is known to lack p16 (44) , which may be important in MIS downstream signaling.4 Thus, OVCAR5 or OVCAR8 cell lines, which should contain all other MIS receptor components, could be used as positive controls for each assay involving patients ascites cells. OVCAR5 would be an ideal positive control for patient ascites binding assays because it can be grown in suspension culture. Furthermore, the OVCAR5 and OVCAR8 cell lines should be very useful in identifying the MIS type I receptor from the seven known type I receptors (19 , 45, 46, 47) and to decipher downstream signal pathway components and the genes regulated by MIS in ovarian cancer cells.
To test whether an MIS response could be receptor mediated in ovarian cancer patients, we examined primary ascites cells isolated from 27 patients with stage III or IV ovarian cancer undergoing staging laparotomy or palliative paracentesis. We attempted to analyze all 27 patients cells for: (a) binding by flow cytometry; (b) detection of the presence of the type II receptor by RT-PCR; and (c) assessment of colony growth in soft agarose with or without MIS. However, because the number of cells in each patients ascites varied substantially, it was not possible to perform each study for all patients. For example, if the patient had received prior chemotherapy or underwent previous palliative paracentesis, the ascites might be hypocellular. Hence, analyses were prioritized according to cell number and the time of ascites acquisition. It is important to note that if cells could not be isolated within 4 h of surgery to limit RNA degradation, RT-PCR was not performed for that patient. If cell numbers were limited, only MIS binding was assessed. Given these limitations, 13 of 27 (48%) of the patients cells were studied by all three tests.
Ascites cells from 15 of 27 (56%) of the patients with late-stage ovarian cancer bound MIS-biotin. This number may be an underestimation of the actual incidence of receptor-positive tumors, because patients forming voluminous ascites secondary to obstructed lymphatics who require repeated palliative paracenteses may have ascites deplete of tumor cells. The nontumor, epithelial/mesothelial cells from these patients might be CA-125 and cytokeratin positive but would be nonbinders and nongrowers in stem cell assays and hence could not be evaluated for MIS response in growth inhibition assays. In the future, we would recommend performing simultaneous cytology to evaluate the presence of tumor cells and to differentiate them from the nontumor epithelial population. Twelve patients did not bind MIS. Six of the 12 patients whose cells did not bind MIS, however, provided enough cells for RNA analysis; of these, 4 had no evidence of type II receptor mRNA. One of the remaining two patients cells failed to grow in colony inhibition and is, therefore, unevaluable. The second patients cells grew and were inhibited by MIS, reflecting the possible technical limitations of flow cytometry, despite its rapid turnaround time. Furthermore, 8 of the 12 nonbinders did not grow or had insufficient numbers of cells to be tested in colony inhibition assays, but of the four that grew, three showed statistically significant inhibition, probably reflecting the technical difficulty of the binding assay. Thus, the colony inhibition assay is a reasonable functional test to predict that all components are present in a patients cells to permit a functional MIS response. The length of time (710 days) required to obtain sufficient colonies in the soft agarose assays for comparison to MIS-treated cultures makes it necessary to use other determinants of response such as the MIS receptor mRNA or protein, together with binding of MIS, in predicting sensitivity to MIS. In future, the use of all three modalities, but in a prioritized paradigm, can give a comprehensive prediction of possible MIS response.
The two patients whose cells bound MIS but did not respond to MIS in antiproliferation assays could reflect mutations in the cytosolic domain of the MIS type II receptor, mutations in the MIS type I receptor, or defects in the molecules downstream of the receptor complex involved in the signal transduction pathway. Once the candidate genes in this pathway are defined, we envision systematic screening of all ovarian cancer patients for sequence abnormalities of all known pathway genes as a fingerprint of each patients tumor.
Despite these potential logistical drawbacks, we can safely say that ovarian cancer cell lines that express the MIS type II receptor by various criteria (Figs. 1
and 3)
respond to MIS (Fig. 1
and Table 1
), and that patients whose ascites cells express the receptor (Figs. 4
and 5, C and D
) also respond to MIS (Table 2)
. The frequency of MIS receptor expression on the ascites cells of ovarian cancer patients is similar to the proportion of breast cancer patients expressing estrogen receptor, a marker used to predict patients who will respond to antiestrogen therapy (48)
. The data presented in the present pool of patients confirm our hypothesis that papillary serous-cystadenocarcinoma ovarian cancers are targets for MIS therapy. Over half of the cases contain the MIS type II receptor and bind MIS. Furthermore, MIS can block proliferation of these cancer cells in a receptor-dependent manner in vitro, suggesting the MIS receptors detected by MIS binding and RT-PCR are functional. The number of in vitro evaluations that can be performed on the clinical cases depends upon the quantity of tumors cells recovered in ascites. Because cell number varies widely from case to case, the tests performed on the clinical samples must be prioritized. The highest priority is given to MIS binding assays because they require the fewest number of cells and the least amount of time to complete. Also, MIS binding predicted the presence of MIS type II receptor mRNA. With rhMIS, the MIS type II receptor, and antibodies to the receptor and ligand, along with methods of production and purification of rhMIS, these carefully developed tools are now in hand to proceed to clinical trials that will test rhMIS as an adjuvant antineoplastic agent for such patients.
We envision that flow cytometry with labeled MIS and/or MIS type II receptor probes would be used to select such patients with recurrent ovarian cancer as candidates for an expeditious Phase I clinical trial for MIS toxicity. Such a well-constructed trial would not preclude early resumption of conventional chemotherapy. Colony inhibition, mRNA, and protein detection would be used for selection of patients for later efficacy trials.
| ACKNOWLEDGMENTS |
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| FOOTNOTES |
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1 This work was partially funded by NIH, National Cancer Institute Grant R01 CA17393, Child Health and Human Development Grant R01 HD32113, and Massachusetts General Hospital Reproductive Science Center Grant P30 HD28138 (to P. K. D. and D. T. M.), National Cancer Institute Grant T32 CA71345 and American College of Surgeons Resident Research Scholarship (to P. T. M.), an American Cancer Society Institutional Award (to S. M.), Child Health and Human Development Grants F32 HD07954 and R29 CA79459 (to J. T.), and a grant from the March of Dimes (to J. T. and P. K. D.). ![]()
2 To whom requests for reprints should be addressed, at Pediatric Surgical Research Laboratories, 55 Fruit Street, WRN 11, Massachusetts General Hospital, Boston, MA 02114-2696. Phone: (617) 726-8839; Fax: (617) 726-5057; E-mail: donahoe.patricia{at}mgh.harvard.edu ![]()
3 The abbreviations used are: MIS, Mullerian inhibiting substance; rhMIS, recombinant human MIS; TGF, transforming growth factor; RT-PCR, reverse transcription-PCR. ![]()
4 T. U. Ha, D. L. Segev, P. K. Donahoe, and S. Maheswaran, unpublished data. ![]()
Received 4/ 8/99; revised 8/ 5/99; accepted 8/17/99.
| REFERENCES |
|---|
|
|
|---|
type II receptor family. Dev. Dyn., 196: 133-142, 1993.[Medline]
type II receptor, a functional transmembrane serine/threonine kinase. Cell, 68: 775-785, 1992.[Medline]
type I receptors that form heteromeric kinase complexes with type II receptors. Cell, 75: 671-680, 1993.[Medline]
and activin. Science (Washington DC), 264: 101-104, 1994.
or activin. Science (Washington DC), 262: 900-902, 1993.This article has been cited by other articles:
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