A phase 1 dose-escalation study to investigate the safety, efficacy, pharmacokinetics, and pharmacodynamic activity of CLN-619 (anti-MICA/MICB antibody) alone and in combination with pembrolizumab in patients with advanced solid tumors

TPS2688

Background: The major histocompatibility complex (MHC) class I-related proteins MICA and MICB are stress-inducible, surface glycoproteins that are up-regulated on human tumors. MICA/MICB are ligands for the activating receptor, Natural Killer Group 2 member D (NKG2D) expressed on Natural Killer (NK) cells, CD8+ T cells, γδ T cells and iNKT cells. Proteases in the tumor microenvironment cleave MICA/MICB from the cell surface which enables tumor cells to evade immune cell recognition and destruction by NKG2D-expressing cells. Increased concentrations of shed MICA have been observed in serum from patients across multiple tumor types and correlate with poor survival. CLN-619 is a humanized, clinical-stage, MICA/MICB-specific IgG1 monoclonal antibody that prevents the proteolytic release of MICA/MICB thereby exposing tumor cells for immune destruction through both NKG2D-mediated and antibody-dependent cell-mediated cytotoxicity (ADCC). The antibody has been shown to restore the MICA/MICB-NKG2D axis to promote NK-mediated tumor cell lysis (AACR Annual Meeting abstract 3506, April 2022). In mice bearing MICA/MICB-expressing human tumor xenografts, CLN-619 treatment yielded robust anti-tumor activity at low doses. MICA/MICB is expressed in a wide range of solid tumors. Therefore, CLN-619 is expected to have broad anti-tumor activity. Methods: CLN-619 is being evaluated in an open-label, non-randomized, dose-escalation (phase 1) study as monotherapy, and in combination with pembrolizumab, in patients with advanced solid tumors. Cohort expansion in patients with specific indications as monotherapy and in combination with pembrolizumab will be conducted. The phase 1 study explores ascending intravenous doses of CLN-619 as monotherapy (0.1, 0.3, 1.0, 3.0, 6.0 and 10.0 mg/kg) and in combination with pembrolizumab (200 mg) in 21-day cycles to identify the maximum tolerated dose (MTD) and recommended Phase 2 dose (RP2D). Key eligibility criteria include 1) histological or cytological diagnosis of cancer and 2) refractory metastatic disease, or locally advanced disease not amenable to local therapy. At the RP2D, CLN-619 monotherapy will be evaluated in non-small cell lung and cervical cancer. In parallel, a cohort of patients will be administered CLN-619 in combination with pembrolizumab. Serum levels of soluble MICA/MICB, identity of MICA/MICB alleles, phenotypes of peripheral blood mononuclear cells, cytokines and tumor biopsies will be investigated for correlative pharmacodynamic and predictive biomarkers. This clinical trial is in progress (NCT05117476) and has completed accrual of three participants at the first dose level. Clinical trial information: NCT05117476.

400 Persistence and tissue distribution of agent-797 – a native allogeneic iNKT cell-therapy drug product

Background

Invariant Natural Killer T (iNKT) cells are key effectors and regulators of immune responses, making them an ideal immunotherapy. There is a paucity of evidence describing the persistence and trafficking of these cells in humans to inform the optimal clinical application. Here, we describe the development of a murine Xenograft model for the study of an unmodified human iNKT cell therapy (Agent-797) and present data on the persistence and tissue distribution of human iNKT cells in this model. We further describe the development and validation of a digital PCR-based methodology to track unmodified allogeneic human iNKT cells in blood and tissue and present exploratory clinical data on iNKT cell persistence in patients with cancer and viral ARDS treated with Agent-797.

Methods

Persistence and tissue distribution of ex-vivo expanded human iNKT cells was investigated in immune compromised mice (NOG), as well as in NOG mice expressing human IL15 (NOG-hIL15), a key cytokine promoting iNKT cell survival. Persistence of iNKT cells was determined over a 35-day period, with takedowns on day 1, 7, 14, 21 and 35. iNKT cells were phenotyped for activation markers by flow cytometry. An assay based on Imegen Quimera digital PCR technology was developed and validated to quantify human iNKT in an allogeneic setting. We employed this assay to measure persistence of Agent-797 drug product in patients participating in clinical trials using iNKT cell-based immunotherapy in viral ARDS (NCT04582201) or multiple myeloma (NCT04754100).

Results

Human IL15 was essential for the engraftment and persistence of human iNKT cells in NOG mice. Following injection, iNKT cells located to the blood, lung, liver, spleen, and bone marrow. iNKT cells persisted most prominently in bone marrow, where they demonstrated an activated phenotype. In mice challenged with hematological tumor cells (ALL cell line NALM6 expressing CD1d) persistence of iNKT cells in blood was prolonged. Initial data from human trials confirmed rapid translocation from peripheral blood of this tissue resident immune cell population following infusion of Agent-797.

Conclusions

We established a murine xenograft model and digital PCR-based methodology to characterize the persistence, trafficking, and efficacy of native allogeneic human iNKT cell-based products. Our models recapitulated the human iNKT distribution and demonstrated iNKTs induced preclinical efficacy in a tumor model. We further successfully developed a validated methodology to track unmodified allogeneic iNKT cells in humans.

Trial Registration

NCT04582201 and NCT04754100

Ethics Approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards

Initial findings of the first-in-human phase I study of AGEN2373, a conditionally active CD137 agonist antibody, in patients (pts) with advanced solid tumors

2634

Background: CD137 is a member of the tumor necrosis factor receptor superfamily that functions as a potent co-stimulator of both adaptive and innate immune cells, thus making it an attractive target for cancer immunotherapy. The development of first-generation anti-CD137 antibodies has been hampered by limited clinical activity or dose-limiting hepatotoxicity. AGEN2373 is a novel, conditionally active CD137 agonist antibody designed to selectively enhance tumor immunity while mitigating side effects associated with systemic activation of CD137. Here we report the initial findings from the first-in-human evaluation of AGEN2373 in pts with advanced solid cancers. Methods: Pts received AGEN2373 on day 1 of a 28-day cycle (Q4W dosing), with cycles repeated until progression, intolerable toxicity or investigator/patient decision. Dose-escalation followed a standard 3+3 scheme, with planned dosing of 0.03, 0.06, 0.3, 1.0, 2.0, and 3.0 mg/kg. The primary objective was to determine the safety, tolerability, and dose-limiting toxicity (DLT) of AGEN2373 as monotherapy. Secondary objectives included pharmacokinetics (PK) and preliminary clinical activity. Adverse events (AEs) were reported per CTCAE v5.0 and DLTs evaluated within a 28-day window. For PK analyses, serum AGEN2373 concentrations determined using a validated bioanalytical assay and simultaneously analyzed by an NLME model. Antitumor activity was assessed using RECIST v1.1. Results: As of January 21 2021, 19 pts (median age 54.4 years, range 33-74; 11 men, 8 women; 7 with prior immunotherapy) have been treated with AGEN2373 Q4W at escalating doses from 0.03 – 2.0 mg/kg across 5 cohorts. Eleven pts (57.9%) experienced treatment-related AEs; none were grade 3 or higher. The most common events were fatigue (4 pts, 21.1%) and nausea (2 pts, 10.6%). No DLTs have been observed. Importantly, no drug-related elevations in liver transaminases (ALT, AST) or bilirubin beyond 1 grade have been seen. AGEN2373 PK were consistent with linear elimination. Prolonged disease stabilization as best response occurred in 5 pts (26.3%; range, 6-41 weeks); three of which were seen in heavily pretreated pts with metastatic leiomyosarcoma, including one who had progressed on prior combination checkpoint immunotherapy. Enrollment into the 3.0 mg/kg cohort is continuing. Conclusions: AGEN2373 demonstrates good tolerability in pts with advanced solid tumors, with a safety profile characterized by a lack of hepatotoxicity frequently observed with CD137-targeting antibodies. These findings underscore the suitability of AGEN2373 as a potential partnering agent for other immunomodulatory agents, including planned expansion as combination therapy with balstilimab (anti-PD-1). Clinical trial information: NCT04121676.

AGEN1181, a clinical stage Fc-engineered anti-CTLA-4 antibody with improved therapeutic potential for the treatment of patients with advanced malignancies

TPS3157

Background: AGEN1181 is a novel Fc-optimized anti-CTLA4 antibody, currently being evaluated in an ongoing multi-center, open-label, phase 1 study in all advanced solid tumors as mono-therapy and combination with anti-PD-1 antibody, AGEN2034 (NCT03860272). AGEN1181 is Fc-engineered to harness a novel mechanism for enhanced FcγR-dependent functionality relative to first-generation CTLA-4 antibodies. In pre-clinical models, AGEN1181 enhances T cell priming, depletion of intratumoral regulatory T cells (Treg) and improved memory formation compared to first-generation anti-CTLA-4 antibodies. Most notably, AGEN1181 demonstrates improved binding to FcyRIIIA and superior T cell responsiveness in populations that only express the low affinity FcγRIIIA receptor relative to first-generation IgG1 CTLA-4 antibodies. The combination of AGEN1181 and AGEN2034 further enhances T cell activation and effector function. Methods: This phase 1 study is an open-label, multi-center dose-escalation designed to evaluate the safety, tolerability, dose limiting toxicity (DLT) PK, and pharmacodynamic profiles of patients with refractory advanced solid tumors who did not receive an anti-CTLA4 previously. The study is being conducted in 3 arms; with patients assigned using a standard 3+3 dose escalation design in the mono-therapy arms with AGEN1181 and an accelerated design in the combination with AGEN2034 arm. AGEN1181 is administered as IV infusion as mono-therapy on Day 1 of every 3 weeks (0.1,0.3,1,2,4 mg/kg), every 6-weeks (1,2,4 mg/kg) in parallel cohorts and every 6-weeks (0.1,0.3,1,2,4 mg/kg) in combination with AGEN2034 (3mg/kg Q2Weeks) until disease progression or unacceptable toxicity (maximum 2 years). All 3 Arms are open and enrolling patients. The study is expected to enroll approximately 80 evaluable patients with solid tumors. Dose reductions are not allowed in the event of AGEN1181-related toxicities. Currently 3 cohorts have been completed, first cohort in the combination arm and the fourth cohort in the monotherapy arm are enrolling. Preclinical and clinical assessment of AGEN1181 supports continued development as a potential therapy for refractory or relapsed advanced solid tumors. Clinical trial information: NCT03860272 .

Integrative molecular analysis of metastatic Merkel cell carcinoma to identify predictive biomarkers of response to avelumab

9569

Background: Avelumab, an FDA-approved human anti–PD-L1 IgG1 monoclonal antibody for patients (pts) with metastatic Merkel cell carcinoma, showed an objective response rate (ORR; by RECIST v1.1) of 31.8% in a second-line phase 2 trial (NCT02155647). We assessed the association of tumor mutational burden (TMB; nonsynonymous somatic variants/megabase), PD-L1 expression, Merkel cell polyomavirus (MCPyV) status, and CD8+ tumor-infiltrating T-cell density with ORR and survival. Molecular profiles (RNAseq and WEX) also were analyzed. Methods: Baseline tumors (n = 36) were profiled using RNAseq and WEX sequencing. PD-L1 expression (≥1% cutoff), MCPyV status, and CD8+ T-cell density at the tumor invasive margin were evaluated by IHC. MHC locus expression was measured with OptiType and loss of heterozygosity (LOH) with LOHHLA. Results: Of 36 pts profiled, 12 had a response, 27 were PD-L1+, and 23 were MCPyV+. The TMB upper tertile and quartile values were 1.34 and 3.16, respectively. Consistent with literature, MCPyV− pts had a higher median TMB (2.72) than MCPyV+ pts (0.49). PD-L1+ tumors trended toward a higher TMB. An empirical cohort-specific TMB cutoff of ≥2 was chosen to include sufficient pts per subgroup. Pts with TMB ≥2 vs TMB < 2 had higher ORR (5 of 11 [45.5%] vs 7 of 25 [28.0%]) and 6-mo PFS rates (60% vs 38%). Among pts with TMB ≥2, the highest ORRs were reported in MCPyV− (4 of 7 pts), PD-L1+ (5 of 9 pts), and CD8+ T-cell density higher than median (5 of 6 pts) subgroups. MHC expression trended with ORR and survival. Higher mean MHC expression was found in pts with CD8+ T-cell density higher than median (p < 0.05). Mutations in antigen presentation genes were detected: LOH at the HLA locus in 9 of 30 pts (28%), including 4 with a response; an NK cell activation signature was also associated with response. These data may suggest that ADCC contributes to response. Factorial analysis of gene signature scores identified signatures (eg, IFNγ, TP53 pathway) associated with MCPyV status and response. Conclusions: Responses in this data set were not attributed to any specific biomarker alone. Future analysis is focused on validating these results and identifying rational drug combinations with avelumab. Clinical trial information: NCT02155647.

Type I superconductivity in Dirac materials

Superconductivity of the second kind was observed in many 3D Weyl and Dirac semi-metals while in the PdTe₂, superconductivity is clearly of the first kind. This is very rare in Dirac semi-metals, but is expected in clean conventional metallic superconductors with 3D parabolic dispersion relation. The conduction bands in this material exhibit the linear (Dirac) dispersion only along two directions, while in the third direction the dispersion is parabolic. Therefore the 'hybrid' Dirac-parabolic material is intermediate between the two extremes. A microscopic pairing theory is derived for arbitrary tilt parameter of the 2D cone and used to determine anisotropic coherence lengths, the penetration depths and applied to recent extensive experiments. Magnetic properties of these superconductors are then studied in the parallel to the layers magnetic field on the basis of microscopically derived Ginzburg-Landau effective theory for the order parameter.

Exploratory biomarker analysis in avelumab-treated patients with metastatic Merkel cell carcinoma progressed after chemotherapy

9557

Background: Merkel cell carcinoma (MCC) is a rare but aggressive skin cancer. Tumor oncogenesis is linked to Merkel cell polyomavirus (MCPyV) integration and UV exposure. PD-L1 is often expressed in MCC tumors, suggesting that patients with MCC could benefit from anti-PD-L1 therapy. Avelumab is a fully human anti-PD-L1 IgG1 monoclonal antibody that has demonstrated clinical efficacy in patients (pts) with metastatic MCC (mMCC) in a Phase 2 trial with an objective response rate (ORR) of 31.8% in the primary analysis. Assessment of candidate predictive biomarkers may help to identify patients with a greater probability of response to avelumab and to improve understanding of MCC biology. Methods: Patients in a Phase 2 trial (NCT02155647) with mMCC and tumor progression on prior chemotherapy received avelumab at 10 mg/kg Q2W. PD-L1 expression, MCPyV status and CD8+ T-cell infiltration in pretreatment tumor samples were evaluated by immunohistochemistry (IHC). MCPyV status was also evaluated by real-time PCR. Results: Tumor PD-L1 expression was evaluable in 74 of 88 (84.1%) pts with mMCC treated with avelumab, of which 58 (65.9%) and 19 (21.6%) pts were positive at 1% and 5% cut-offs. ORR was 34.5% and 18.8% for PD-L1 positive and negative pts at 1% cutoff, and 52.6% and 23.6% for PD-L1 positive and negative pts at 5% cutoff. MCPyV status was positive in 60% (46/77) pts evaluable by IHC and 63% (45/71) pts evaluable by PCR; of 66 pts tested by both IHC and PCR, concordance was 90.9%. MCPyV+ and MCPyV– pts had similar frequencies of PD-L1+ tumors (80% and 73%) with an ORR of 26.1% and 35.5% respectively. Baseline CD8+ T-cell infiltration was assessed at tumor invasive margin and tumor center in 53 pts, ORR was 44.4% vs 19.2% and 32.1% vs 28% for pts with high or low CD8+ T-cell density at respective locations. Conclusions: In an international cohort of pts with mMCC, avelumab had clinical activity among biomarker subgroups analyzed, including PD-L1 expression, MCPyV status and density of CD8+ tumor-infiltrating T-cells. The current biomarkers were not predictive of response but further research into understanding how avelumab mediates anti-tumor activity in MCC may identify novel biomarkers. Clinical trial information: NCT02155647.

Prediction of microcephaly at birth using three reference ranges for fetal head circumference: can we improve prenatal diagnosis?

OBJECTIVE

To evaluate the prediction of microcephaly at birth (micB) using established and two new reference ranges for fetal head circumference (HC) and to assess whether integrating additional parameters can improve prediction.

METHODS

Microcephaly in utero was defined as a fetal HC 3SD below the mean for gestational age according to Jeanty et al.'s reference range. The records of cases with fetal microcephaly (Fmic) were evaluated for medical history, imaging findings, biometry and postnatal examination/autopsy findings. Microcephaly was confirmed at birth (micB) by an occipitofrontal circumference (OFC) or a brain weight at autopsy 2SD below the mean for gestational age. The new INTERGROWTH-21(st) Project and a recent Israeli reference for fetal growth were applied for evaluation of the Fmic positive predictive value (PPV) for diagnosis of micB cases. Optimal HC cut-offs were determined for each of the new references with the aim of detecting all micB cases whilst minimizing the number of false positives found to have a normal HC at birth. We also assessed the difference between the Z-scores of the prenatal HC and the corresponding OFC at birth, the frequency of small-for-gestational age (SGA), decreased HC/abdominal circumference (AC) and HC/femur length (FL) ratios, the prevalence of associated malformations and family history.

RESULTS

Forty-two fetuses were diagnosed as having Fmic according to the Jeanty reference, but micB was confirmed in only 24 (PPV, 57.1%). The optimal INTERGROWTH and Israeli reference HC cut-offs for micB diagnosis were mean - 3SD and mean - 2.3SD, resulting in a statistically non-significant improvement in PPV to 61.5% and 66.7%, respectively. The presence of a family history of microcephaly, SGA, associated malformations and application of stricter HC cut-offs resulted in a higher PPV of micB, although not statistically significant and with a concurrent increase in the number of false-negative results. The deviation of the HC from the mean, by all references, was significantly larger compared with the actual deviation of the OFC at birth, with mean differences between the corresponding Z-scores of -1.15, -1.95 and -0.74 for the Jeanty, INTERGROWTH and Israeli references, respectively.

CONCLUSIONS

The evaluated reference ranges all result in considerable over-diagnosis of fetal microcephaly. The use of the two new HC reference ranges did not significantly improve micB prediction compared with that of Jeanty et al., whilst use of additional characteristics and stricter HC cut-offs could improve the PPV with an increase in false negatives. The postnatal OFC deviates significantly less from the mean compared with the prenatal HC, and we propose that adjustment for this would enable better prediction of the actual OFC deviation at birth. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Application of a novel prenatal vertical cranial biometric measurement can improve accuracy of microcephaly diagnosis in utero

OBJECTIVE

To construct a reference range for a new vertical measurement of the fetal head and to assess whether its combination with fetal head circumference (HC) can prevent the misdiagnosis of microcephaly in fetuses with an acrocephalic-like head deformation.

METHODS

A new vertical cranial biometric measurement was defined: the foramen magnum-to-cranium distance (FCD), measured between the foramen magnum and the upper inner cranial border along the posterior wall of the brainstem. The measurement was performed in a precise mid-sagittal plane using a three-dimensional multiplanar display of a sagittally acquired sonographic volume of the fetal head. The normal reference range was developed by measuring 396 healthy fetuses of low-risk singleton pregnancies between 15 and 40 gestational weeks. This reference was applied to 25 fetuses with microcephaly diagnosed prenatally (Fmic) based on HC ≥ 3 SD below the mean for gestational age. We determined an optimal FCD cut-off for combination with HC to detect all cases found with microcephaly at birth (micB), while excluding the fetuses with normal head circumference at birth (NHCB), who were described postnatally as having an acrocephalic-like cranial deformation.

RESULTS

In the healthy singleton fetuses, FCD increased with gestational age, with a quadratic equation providing an optimal fit to the data (adjusted R(2) = 0.934). The measurement could be assessed in 95.2% of cases. Of the 25 cases diagnosed with Fmic prenatally, on the basis of HC alone, 14 were micB and 11 were NHCB. We observed FCD below the mean - 2SD for gestational age in all 14 micB cases, but in only four of the 11 NHCB cases (P < 0.003). An acrocephalic-like cranial deformation was described at birth in five of the seven NHCB cases with normal FCD. The mean ± SD FCD Z-score of the micB cases was significantly lower (P < 0.001) than that of the false-positive ones: -3.85 ± 0.96 SD and -1.59 ± 1.45 SD, respectively. Based on HC measurement alone, the positive predictive value (PPV) was 56%. Combination of the HC and FCD criteria raised the PPV to 78%, decreasing the number of false positives from 11 to four, without missing any of the 14 micB cases.

CONCLUSIONS

Fetal vertical cranial biometric assessment in the mid-sagittal plane is feasible and correlates well with gestational age. In our series, a vertical cranial deformation was a frequent cause of a false Fmic diagnosis made on the basis of HC alone. Combination of the new vertical cranial biometric measurement with HC measurement can exclude these cases and thus improve diagnostic accuracy for Fmic. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Triplet superconductivity in 3D Dirac semi-metal due to exchange interaction

Conventional phonon-electron interaction induces either triplet or one of two (degenerate) singlet pairing states in time reversal and inversion invariant 3D Dirac semi-metal. Investigation of the order parameters and energies of these states at zero temperature in a wide range of values of chemical potential μ, the effective electron-electron coupling constant λ and Debye energy TD demonstrates that when the exchange interaction is neglected the singlet always prevails, however, in significant portions of the (μ, λ, TD) parameter space the energy difference is very small. This means that interactions that are small, but discriminate between the spin singlet and the spin triplet, are important in order to determine the nature of the superconducting order there. The best candidate for such an interaction in the materials under consideration is the exchange (the Stoner term) characterized by constant λex. We show that at values of λex, much smaller than ones creating Stoner instability to ferromagnetism λex ∼ 1, the triplet pairing becomes energetically favored over the singlet ones. The 3D quantum critical point at μ = 0 is considered in detail. This can be realized experimentally in optically trapped cold atom systems.

Assessment of fetal midbrain and hindbrain in mid-sagittal cranial plane by three-dimensional multiplanar sonography. Part 2: application of nomograms to fetuses with posterior fossa malformations

OBJECTIVES

To apply fetal midbrain (MB) and hindbrain (HB) nomograms, developed using three-dimensional multiplanar sonographic reconstruction (3D-MPR) in the mid-sagittal cranial plane, to fetuses with known posterior fossa malformations.

METHODS

In this retrospective study we examined sonographic volumes obtained by sagittal acquisition in 43 fetuses diagnosed with posterior fossa abnormalities and evaluated in the mid-sagittal cranial plane, using 3D-MPR, the following: MB parameters tectal length (TL) and anteroposterior midbrain diameter (APMD), and HB parameters anteroposterior pons diameter (APPD), superoinferior vermian diameter (SIVD) and anteroposterior vermian diameter (APVD). Fetuses were grouped, according to malformation, into eight categories: cobblestone malformation complex (CMC, n = 3), Chiari-II malformation (C-II, n = 7), pontocerebellar hypoplasia (PCH, n = 2), rhombencephalosynapsis (RES, n = 4), Dandy-Walker malformation (n = 8), vermian dysgenesis (VD, n = 7), persistent Blake's pouch cyst (n = 6) and megacisterna magna (n = 6). In each case and for each subgroup, the MB-HB biometric parameters and their z-scores were evaluated with reference to our new nomograms.

RESULTS

The new MB-HB nomograms were able to identify the brainstem and vermian anomalies and differentiate fetuses with MB-HB malformations from those with isolated enlarged posterior fossa cerebrospinal fluid spaces. Use of the nomograms enabled detection of an elongated tectum in fetuses with CMC, C-II and RES, and a flattened pontine belly in cases of CMC, PCH and VD. In the fetuses with VD, the nomograms enabled division into three distinctive groups: (1) those with small SIVD and APVD, (2) those with normal SIVD but small APVD, and (3) those with small SIVD but normal APVD.

CONCLUSIONS

Application of our new reference data, that for the first time include the MB, enables accurate diagnosis of brain malformations affecting the MB and HB and makes possible novel characterization of previously described features of posterior fossa anomalies.

Assessment of fetal midbrain and hindbrain in mid-sagittal cranial plane by three-dimensional multiplanar sonography. Part 1: comparison of new and established nomograms

OBJECTIVE

To construct nomograms for fetal midbrain (MB) and hindbrain (HB) dimensions, assessed in the mid-sagittal cranial plane by three-dimensional multiplanar sonographic reconstruction (3D-MPR).

METHODS

This was a prospective cross-sectional study of 334 healthy fetuses in low-risk singleton pregnancies between 16 and 35 gestational weeks. All sonographic volumes were obtained by sagittal acquisition. The following MB and HB parameters were evaluated in the mid-sagittal cranial plane using 3D-MPR: MB parameters tectal length (TL) and anteroposterior midbrain diameter (APMD), and HB parameters anteroposterior pons diameter (APPD), superoinferior vermian diameter (SIVD), anteroposterior vermian diameter (APVD) and anteroposterior diameter of the fourth ventricle (APDFV). The measurements were presented as growth charts according to gestational age.

RESULTS

MB and HB biometry were best assessed between 19 and 29 weeks. During this period, adequate visualization was achieved for successful measurement of TL in 90.9% of cases, APMD in 86.6%, APPD in 73.7%, SIVD in 74.2%, APVD in 71% and APDFV in 71%. There was a linear growth pattern, with Pearson correlation coefficients of 0.79 for TL, 0.88 for APMD, 0.91 for APPD, 0.95 for SIVD, 0.88 for APVD and 0.88 for APDFV (P < 0.0001 for each). The mean intra- and interobserver variations for the MB measurements and vermian diameters ranged between 4.3% and 9%. APPD and APDFV showed highest mean variations: 9.0% and 19.4% (intraobserver) and 11.6% and 17.7% (interobserver), respectively.

CONCLUSION

We present new nomograms for assessment of the fetal MB and HB using 3D-MPR in the mid-sagittal cranial plane. To our knowledge, these are the first proposed nomograms for fetal MB dimensions.

Fetal posterior fossa dimensions: normal and anomalous development assessed in mid-sagittal cranial plane by three-dimensional multiplanar sonography

OBJECTIVES

To construct nomograms of the dimensions of the fetal posterior fossa (PF), assessed in the mid-sagittal plane in the second and third trimesters, and to assess how measurements from fetuses with PF abnormalities deviate from our normal ranges.

METHODS

This was a prospective cross-sectional study of 378 healthy fetuses in low-risk singleton pregnancies between 15 and 35 weeks. PF size was evaluated in the mid-sagittal plane of the fetal head using three-dimensional multiplanar reconstruction (3D-MPR). The borders of the PF were defined from the clivus to the tentorium (clivotentorial distance, CTD) and from the occipital bone to the level of the upper mesencephalic edge (tecto-occipital distance, TOD), and the posterior fossa area (PFA) and perimeter (PFP) were assessed. Growth charts were produced. Thirty-nine fetuses diagnosed with PF malformations were analyzed by calculating the z-scores of PFA, PFP, TOD and CTD, relative to the developed nomograms.

RESULTS

Of the 378 healthy fetuses initially included, there were 281 with adequate visualization of the PF borders; i.e. PF mid-sagittal plane morphometry was feasible in 74.3% of cases. There was a linear relationship between each of PFA, PFP, TOD and CTD, and gestational age, with Pearson correlation coefficients of 0.97, 0.97, 0.96 and 0.95, respectively (P < 0.001 for each). Chiari II malformation (CM-II) and Dandy-Walker malformation (DWM) were associated with the greatest difference in PF size compared with normal; PFA z-scores exceeded 2.6 in all five DWM cases and were below -2.66 in all 11 CM-II cases.

CONCLUSIONS

Sonographic evaluation of fetal PF size in the mid-sagittal plane is feasible. Our constructed nomograms provide reference data that may be helpful when evaluating PF congenital malformations.

Sonographic imaging of fetal tympanic rings

OBJECTIVE

To examine the feasibility of ultrasonographic imaging of fetal tympanic rings.

METHODS

This was an observational cohort study of 80 healthy fetuses in low-risk pregnancies, divided into four gestational-age subgroups (12, 16, 23 and 32 weeks), each comprising 20 consecutive fetuses. Tympanic ring visualization was achieved by two-dimensional and three-dimensional (3D) sonography. A standard algorithm for tympanic ring examination was constructed using 3D multiplanar reconstruction. The volume acquisition plane was directed to the inferolateral aspect of the fetal temporal bone. Transvaginal scans were carried out in the 12-week and 16-week subgroups, and transabdominal scans in the 23-week and 32-week subgroups. Study parameters included the inferomedial inclination angle (IMIA) of the tympanic ring relative to the vertical skull axis, the anteromedial inclination angle (AMIA) of the tympanic ring relative to the anteroposterior skull axis and the longest (LTRD) and shortest (STRD) tympanic ring diameter, the latter measured perpendicular to the LTRD. The feasibility of tympanic ring demonstration was assessed in each gestational-age subgroup.

RESULTS

Tympanic rings appeared as round-oval, thin, echogenic structures in a plane tangential to the inferolateral surface of the fetal skull below the inferior border of the squamous part of the temporal bone. Higher demonstration rates were achieved in the 16-week and 23-week subgroups (90% and 80%, respectively) than in the others. LTRD and STRD each showed a linear correlation with gestational age (r = 0.96 for both measurements; P < 0.01). Mean IMIA ranged from 41.0 to 60.4° and mean AMIA from 17.3 to 23.4° across the different gestational-age subgroups. The malleal manubrium was observed only in examinations in the second half of pregnancy, appearing as a bright echo within the upper area of the tympanic ring in 56% (9/16) and 82% (9/11) of cases with tympanic ring imaging appropriate for measurement of the study parameters in the 23-week and 32-week subgroups, respectively.

CONCLUSION

This is the first report of sonographic imaging of fetal tympanic rings and shows that this is feasible in the second trimester. We discuss the possible implications of our findings for the prenatal diagnosis of congenital hearing loss.

Abstract A31: Merlin loss as a biomarker for defactinib (VS-6063) sensitivity: High frequency in malignant mesothelioma tumors

Malignant pleural mesothelioma (MPM) is an aggressive tumor in the lining of the lung often caused by asbestos exposure. With a median survival on standard of care chemotherapy of only 12 months from diagnosis, new therapeutic modalities and predictive biomarkers are urgently needed for MPM patients. The Neurofibromatosis 2 (NF2) tumor suppressor gene that encodes the protein merlin is disrupted in approximately 50% of MPMs. The role of merlin in cell adhesion, invasion and cell motility may be partially mediated through the focal adhesion kinase (FAK), an important signaling node downstream of integrin cell adhesion proteins. An examination of 15 mesothelioma cell lines grown in 3-dimensional Matrigel culture demonstrates that low merlin by immunoblotting correlated with increased sensitivity to the FAK inhibitor, defactinib (VS-6063). An immunohistochemistry (IHC) test for merlin may be an optimal clinical tumor specimen measurement for merlin loss, provided that merlin reduction or loss is correlated with other indicators of NF2 change. The presence or absence of merlin and NF2 was evaluated using MPM patient-derived xenograft (PDX) tumor models using merlin IHC and an NF2 Fluorescence In situ Hybridization (FISH), as well as Western blotting to determine merlin levels in the tumor lysates. The PDX MPM-0235 tumor had low merlin by Western blotting, merlin IHC, and NF2 FISH, whereas PDX MPM-0237 showed high merlin levels by Western blotting, merlin IHC, and diploid chromosome 22 by FISH. In addition to PDX analysis, Merlin IHC and NF2 FISH optimized by these conditions was evaluated with in patient MPM Tissue Microarrays (TMAs) of 64 primary tumors. Chromosome 22 monosomy was significantly more frequent than NF2 regional deletion of chromosome 22. We observed that 42% of the tumors had a low merlin IHC score (merlin-low) that correlated with loss of NF2 (unpaired t-test, p&lt;0.029). In a second cohort of archived tumor specimens from 300 MPM patients treated at one clinical site, we observed a similar association between NF2 loss/deletion by FISH and merlin-low IHC (unpaired t-test, p=0.0001). While phosphoFAK Y397 IHC (an indicator of FAK activation) have high IHC values in some tumors that are merlin-low, these two marker trends were not statistically associated for all the tumors in the cohort. These data support the clinical development of a merlin IHC test for evaluation of NF2-mutated malignant mesothelioma. Merlin IHC will be used as a predictive biomarker for responsiveness to defactinib, a selective and potent FAK inhibitor under investigation in a Phase 2 registration-directed clinical trial for patients with MPM.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A31.

Citation Format: David T. Weaver, Irina Shapiro, Christian Vidal, Qunli Xu, Mahesh Padval, Jonathan Pachter, Daniel Paterson, Jullianne Barlow, William Richards, Sabina Signoretti, Raphael Bueno. Merlin loss as a biomarker for defactinib (VS-6063) sensitivity: High frequency in malignant mesothelioma tumors. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A31.

Abstract 236: Pharmacological and genetic inhibition of FAK attenuates cancer stem cell function in vitro and in vivo

Focal adhesion kinase (FAK) is a cytoplasmic tyrosine kinase that orchestrates cell signaling through integrins and growth factor receptors. FAK has been implicated in multiple steps of carcinogenesis including tumor initiation, growth and metastasis. Amplification and overexpression of FAK have been observed in multiple aggressive human cancers including breast and ovarian. VS-4718 is a potent and selective FAK kinase inhibitor that was previously shown by us to exhibit preferential inhibitory activities on breast cancer stem cells. We have further extended our investigation of the role of FAK on cancer stem cells to other solid tumors and report here that pharmacological attenuation of FAK activity by VS-4718 or RNAi-mediated depletion of FAK exhibits preferential inhibitory effects on cancer stem cells.

To determine if FAK plays a role in the biology of cancer stem cells, we depleted FAK expression in breast, ovarian and mesothelioma cancer cell lines by RNAi. Our results indicated that shRNA-mediated knock-down of FAK inhibits tumorsphere formation in vitro. In parallel, VS-4718 was evaluated in a multitude of cancer stem cell assays both in vitro and in vivo. Pre-treatment of SUM159 cells with VS-4718 in matrigel reduced the percentage of ALDEFLUOR+ cancer stem cells and side population (SP). Similar effects were observed in ovarian cancer cell lines OVCAR-8 and OVCAR-5 where VS-4718 inhibited cancer stem cells as measured by multiple CSC assays. In an analogous fashion, VS-4718 also reduced the proportion of the ALDEFLUOR+ cells in H2052 human mesothelioma cells. In direct contrast, standard-of-care agents paclitaxel, carboplatin or pemetrexed increased the percentage of cancer stem cells, suggesting these agents do not effectively target cancer stem cells. Importantly combination of VS-4718 with standard-of-care agents attenuated chemotherapy-induced increases in the percentage of cancer stem cells in vitro in all three cancer models.

The in vivo effect of VS-4718 on cancer stem cells was evaluated in SUM159 and MDA-MB-231 human triple negative breast cancer xenograft models. Following systemic administration, VS-4718 significantly reduced the proportion of cancer stem cells in tumors as evidenced by decreases in the percentage of ALDEFLUOR+ cells and tumorsphere-forming efficiency relative to vehicle-treated tumors and significantly abrogated tumor-initiating capabilities of cancer cells in a limiting dilution re-implantation assay.

In summary, our results indicate the importance of FAK in the self-renewal of cancer stem cells in vitro and in vivo, and support the clinical development of FAK inhibitors to target cancer stem cells for the treatment of multiple cancers.

Citation Format: Vihren Kolev, Quentin Wright, Christian Vidal, Irina Shapiro, Mahesh Pavdal, Mitchell Keegan, Qunli Xu, Jonathan Pachter. Pharmacological and genetic inhibition of FAK attenuates cancer stem cell function in vitro and in vivo. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 236. doi:10.1158/1538-7445.AM2013-236

Effect of nanoholes on the vortex core fermion spectrum and heat transport in p-wave superconductors

The spectrum of core excitations of the Abrikosov vortex pinned by a nanohole of the size of the coherence length is considered. While the neutral zero energy Majorana core state remains intact due to its topological origin, the energy of charged excitations is significantly enhanced compared to that in the unpinned vortex. As a consequence of the pinning the minigap separating the Majorana state from the charged levels increases from Δ(2)/E(F) (E(F) is the Fermi energy and Δ is the bulk p-wave superconducting gap) to a significant fraction of Δ. Suppression of the thermodynamic and kinetic effects of the charged excitations allows us to isolate the Majorana state so it can be used for quantum computation. It is proposed that thermal conductivity along the vortex cores is a sensitive method to demonstrate the minigap. Using the Butticker-Landauer-Kopnin formula, we calculate the thermal conductance beyond the linear response as a function of the hole radius.

Characterization of NCI-H295R cells as an in vitro model of hyperaldosteronism

In depth analysis of key molecular mechanisms involved in functional autonomy of aldosterone secretion is hampered by the lack of tumor cell lines that reflect functional characteristics of aldosterone producing adenomas. Herein, we describe the characteristics of the adrenocortical carcinoma cell line NCI-H295R and its suitability as a model of hyperaldosteronism in relation to different culture conditions. Steroid profiling revealed that NCI-H295R cells predominantly secrete cortisol, while aldosterone and other steroids are released at much lower concentrations. However, aldosterone output specifically increased in response to different stimuli such as ACTH and angiotensin II, and in particular to potassium in a dose dependent manner. NCI-H295R cells readily formed spheroids under specific culture conditions, a method widely used for the enrichment of progenitor cells. Unexpectedly, spheroid cells excelled with higher aldosterone concentration and higher expression levels of the steroidogenic enzymes StAR, 3βHSD, CYP17, SF-1, and the MC2-receptor. Further investigations revealed that this phenomenon is mainly attributed to epithelial growth factor (EGF) and particularly fibroblast growth factor (FGF), which are both essential ingredients in the spheroid culture medium. Aldosterone release under the combinatory influence of EGF and FGF was not higher than the effect of FGF alone. Spheroid growth per se, therefore, does not ensure an enrichment of less differentiated cell types in this cell line.

Abstract LB-192: The FAK inhibitors VS-4718 and VS-5095 attenuate breast cancer stem cell function in vitro and tumor growth in vivo

As a key mediator of integrin signaling, focal adhesion kinase (FAK) regulates cellular responses to extracellular matrix interactions. Amplification and overexpression of FAK have been observed in aggressive human cancers including breast cancer. FAK has been implicated in multiple steps in carcinogenesis including tumor growth, metastasis and angiogenesis. We now demonstrate the importance of FAK in breast cancer stem cell function, and the reduction of cancer stem cell function by the selective FAK inhibitors VS-4718 and VS-5095. VS-4718 and VS-5095 are potent and selective FAK inhibitors which were optimized following high throughput screening. Both VS-4718 and VS-5095 block fibronectin-stimulated FAK autophosphorylation of Tyr397 with low nanomolar cellular potency and are highly selective for FAK among a panel of protein kinases. Consistent with their mechanism of action, VS-4718 and VS-5095 showed greater inhibitory potency on the growth of multiple cancer cell lines in 3D matrigel culture as compared to conventional 2D culture. To determine if FAK plays a role in the biology of breast cancer stem cells in addition to its reported function in normal mammary stem cell biology, the effects of these FAK inhibitors were characterized using two different in vitro assays. It was previously demonstrated that immortalized mammary epithelial cells (HMLEs) driven to undergo epithelial to mesenchymal transition (EMT) by knockdown of E-cadherin (HMLE-shECad) exhibit many of the characteristics of cancer stem cells and can be used to identify agents that selectively target cancer stem cells. VS-4718 exhibited 25-fold greater potency against proliferation of mesenchymal HMLE-shECad cells as compared to epithelial HMLE-shGFP control cells, suggesting preferential effects on breast cancer stem cells. Furthermore, pre-treatment of SUM159 triple negative breast cancer cells with VS-5095 in matrigel attenuated secondary tumorsphere formation, suggesting that FAK is important for the self-renewal function of breast cancer stem cells. The role of FAK in breast cancer stem cell renewal was further corroborated by the observation that FAK shRNA inhibited tumorsphere formation by SUM159 cells. The in vivo efficacy of the FAK inhibitor VS-5095 was evaluated in the MDA-MB-231 human triple negative breast cancer xenograft model. By oral administration, VS-5095 induced significant dose-dependent tumor growth inhibition. In summary, these results demonstrate the importance of FAK in the self-renewal of breast cancer stem cells, and support the clinical development of the selective FAK inhibitors VS-4718 and VS-5095 to target breast cancer stem cells for the treatment of triple negative breast cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-192. doi:1538-7445.AM2012-LB-192

Aldosterone producing adrenal adenomas are characterized by activation of calcium/calmodulin-dependent protein kinase (CaMK) dependent pathways

Primary aldosteronism is the most prevalent cause of secondary hypertension. However, insights in pathophysiological mechanisms resulting in autonomous aldosterone secretion are limited. Although transcriptional regulators of aldosterone synthase (CYP11B2) including calcium-binding calmodulin kinase (CaMK) dependent pathways have been defined in vitro, it remains uncertain whether these mechanisms play a role in the context of dysregulated steroidogenesis in aldosterone producing adrenadenomas. Thus, we compared expression and activation of key components of CaMK pathways in aldosterone producing adenomas (APAs) with normal adrenals glands (NAGs). As expected, aldosterone synthase expression in APAs was significantly higher in comparison to NAGs, suggesting transcriptional activation as a contributing factor of aldosterone excess. Along the same line, CaMKI was significantly upregulated in APAs on the mRNA and protein level. Furthermore, immunohistochemistry revealed nuclear localization of CaMKI in these tumors. The phosphorylation of CREB, a target protein for CaMKI was increased, which could represent a further stimulation of aldosterone synthase transcription. In summary, this study provides indirect evidence for a causative involvement of the CaM kinase signaling pathway in human aldosterone producing adenomas.

Three-dimensional power Doppler in the evaluation of painful leiomyomas and focal uterine thickening in pregnancy

OBJECTIVE

To determine the usefulness of 3-dimensional (3D) power Doppler ultrasound in distinguishing painful leiomyomas from focal myometrial contractions or nonpainful leiomyomas in pregnancy.

METHODS

A 2D section of the area of interest in the uterine wall was first obtained in 29 patients to determine whether the pain originated from a myoma or a uterine contraction. Then, volume acquisition was activated and Doppler indices (vascularization index, flow index, and vascularization-flow index) were calculated for thickened and normal uterine wall.

RESULTS

Of 15 patients found to have uterine myomas, 11 had multiple tumors and 4 had single tumors. In the remaining 14 patients the painful uterine thickening proved to be a focal contraction. Painful segments of uterine thickening were associated with lower Doppler indices. Painful myomas were found to have significantly lower indices than normal uterine wall (P=0.008, 0.03, and 0.01 for VI, FI, and VFI, respectively, vs. 0.001, 0.003, and 0.01). However, the differences in indices between nonpainful myomas and uterine wall on the one hand, and nonpainful myomas and focal uterine contractions on the other, were not statistically significant.

CONCLUSION

Three-dimensional power Doppler ultrasound may be a sensitive and reliable tool for distinguishing painful uterine myomas from focal myometrial contractions and nonpainful myomas.

Spatiotemporal vortex matter oscillations in Bi2Sr2CaCu2O8+delta crystals

We observed an oscillatory behavior, both in space and time, of the induction in Bi2Sr2CaCu2O8+delta crystals exposed to a steady magnetic field. This new "flux waves" phenomenon appears near the order-disorder vortex phase transition, under specific conditions of temperature and induction gradient. A theoretical description of this effect is based on two coupled equations: the Landau-Khalatnikov dynamic equation for the order parameter of the vortex phase transition and the diffusion equation for the time evolution of the magnetic induction. A linear stability analysis of these equations predicts an oscillatory instability characterized by a period and wavelength in accordance with the experimental results.

3D and 4D ultrasound in fetal cardiac scanning: a new look at the fetal heart

Over the last decade we have been witness to a burgeoning literature on three-dimensional (3D) and four-dimensional (4D) ultrasound-based studies of the fetal cardiovascular system. Recent advances in the technology of 3D/4D ultrasound systems allow almost real-time 3D/4D fetal heart scans. It appears that 3D/4D ultrasound in fetal echocardiography may make a significant contribution to interdisciplinary management team consultation, health delivery systems, parental counseling, and professional training. Our aim is to review the state of the art in 3D/4D fetal echocardiography through the literature and index cases of normal and anomalous fetal hearts.

A Novel Phospholipid Derivative of Indomethacin, DP-155 [Mixture of 1-Steroyl and 1-Palmitoyl-2-{6-[1-(p-chlorobenzoyl)-5-methoxy-2-methyl-3-indolyl acetamido]hexanoyl}-sn-glycero-3-phosophatidyl Choline], Shows Superior Safety and Similar Efficacy in Reducing Brain Amyloid β in an Alzheimer's Disease Model

Indomethacin has been suggested for the treatment of Alzheimer's disease (AD), but its use is limited by gastrointestinal and renal toxicity. To overcome this limitation, D-Pharm Ltd. (Rehovot, Israel) developed DP-155 (mixture of 1-steroyl and 1-palmitoyl-2-{6-[1-(p-chlorobenzoyl)-5-methoxy-2-methyl-3-indolyl acetamido] hexanoyl}-Sn-glycero-3-phosophatidyl [corrected] choline), a lecithin derivative of indomethacin. Safety was tested by daily oral administration of DP-155 or indomethacin to rats in a dose range of 0.007 to 0.28 mmol/kg. The prevalence of gastrointestinal ulceration was significantly lower (10-fold) for DP-155 than for indomethacin, and the ulcerations were delayed. Signs of renal toxicity, namely reduced urine output and increased urine N-acetyl glycosaminidase to creatinine ratio, were 5-fold lower for DP-155. Indomethacin, but not an equimolar dose of DP-155, reduced urine bicyclo-prostaglandin E(2). An equimolar oral dose of DP-155 or indomethacin, administered every 4 h for 3 days, was equally efficacious in reducing the levels of Abeta42 in the brains of Tg2576 mice. Indomethacin was the principal metabolite of DP-155 in the serum. After DP-155 oral administration, indomethacin's half-life in the serum and the brain was 22 and 93 h, respectively, compared with 10 and 24 h following indomethacin oral administration. The brain to serum ratio was 3.5 times higher for DP-155 than indomethacin. This finding explains the efficacy of DP-155 in reducing Abeta42 brain levels, despite the low systemic blood concentrations of indomethacin derived from DP-155. In conclusion, compared with indomethacin, DP-155 has significantly lower toxicity in the gut and kidney while maintaining similar efficacy to indomethacin in lowering Abeta42 in the brains of Tg2576 mice. This superior safety profile highlights DP-155's potential as an improved indomethacin-based therapy for AD.

Misorientation and reduced stretching of aligned sister kinetochores promote chromosome missegregation in EB1- or APC-depleted cells

The correct formation of stable but dynamic links between chromosomes and spindle microtubules (MTs) is essential for accurate chromosome segregation. However, the molecular mechanisms by which kinetochores bind MTs and checkpoints monitor this binding remain poorly understood. In this paper, we analyze the functions of six kinetochore-bound MT-associated proteins (kMAPs) using RNAi, live-cell microscopy and quantitative image analysis. We find that RNAi-mediated depletion of two kMAPs, the adenomatous polyposis coli protein (APC) and its binding partner, EB1, are unusual in affecting the movement and orientation of paired sister chromatids at the metaphase plate without perturbing kinetochore-MT attachment per se. Quantitative analysis shows that misorientation phenotypes in metaphase are uniform across chromatid pairs even though chromosomal loss (CIN) during anaphase is sporadic. However, errors in kinetochore function generated by APC or EB1 depletion are detected poorly if at all by the spindle checkpoint, even though they cause chromosome missegregation. We propose that impaired EB1 or APC function generates lesions invisible to the spindle checkpoint and thereby promotes low levels of CIN expected to fuel aneuploidy and possibly tumorigenesis.

Ring-shaped vortex domain in type-II superconductors

We present results of experiments in superconducting niobium and numerical simulations showing the creation of a metastable ring-shaped vortex domain by heating. Such vortex rings, if pinned by structural defects, can exist forever.

A signaling pathway leading to metastasis is controlled by N-cadherin and the FGF receptor

The intracellular signaling events causing tumor cells to become metastatic are not well understood. N-cadherin and FGF-2 synergistically increase migration, invasion, and secretion of extracellular proteases in breast tumor cells. Here, we define a metastatic signaling cascade activated by N-cadherin and FGF-2. In the presence of N-cadherin, FGF-2 caused sustained activation of the MAPK-ERK pathway, leading to MMP-9 gene transcription and cellular invasion. N-cadherin prevented the FGF receptor (FGFR) from undergoing ligand-induced internalization, resulting in increased FGFR-1 stability. Association of FGFR-1 with N-cadherin was mediated by the first two Ig-like domains of FGFR-1. These results suggest that protection of the FGFR-1 from ligand-induced downregulation by N-cadherin enhances receptor signaling and provides a mechanism by which tumor cells can acquire metastatic properties.