RANK is a poor prognosis marker and a therapeutic target in ER-negative postmenopausal breast cancer

Despite strong preclinical data, the therapeutic benefit of the RANKL inhibitor, denosumab, in breast cancer patients, beyond the bone, is unclear. Aiming to select patients who may benefit from denosumab, we hereby analyzed RANK and RANKL protein expression in more than 2,000 breast tumors (777 estrogen receptor-negative, ER- ) from four independent cohorts. RANK protein expression was more frequent in ER- tumors, where it associated with poor outcome and poor response to chemotherapy. In ER- breast cancer patient-derived orthoxenografts (PDXs), RANKL inhibition reduced tumor cell proliferation and stemness, regulated tumor immunity and metabolism, and improved response to chemotherapy. Intriguingly, tumor RANK protein expression associated with poor prognosis in postmenopausal breast cancer patients, activation of NFKB signaling, and modulation of immune and metabolic pathways, suggesting that RANK signaling increases after menopause. Our results demonstrate that RANK protein expression is an independent biomarker of poor prognosis in postmenopausal and ER- breast cancer patients and support the therapeutic benefit of RANK pathway inhibitors, such as denosumab, in breast cancer patients with RANK+ ER- tumors after menopause.

Abstract P2-08-10: First results of the randomized window of opportunity clinical trial D-Biomark: Immunomodulatory effect of denosumab in early breast cancer

Background: Most breast cancers (BC) exhibit low immune infiltration and are unresponsive to immunotherapy. Inhibitors of the Receptor Activator of NFkB (RANK) pathway, such as denosumab, used for the treatment of bone metastasis, have been shown to prevent BC, reducing tumor cell proliferation and survival. Our recent data supports that RANK pathway inhibition in BC cells enhances anti-tumor immune response. However, the population of BC patients who may benefit from denosumab remains to be identified. The aim of the study is to evaluate the antiproliferative, proapoptotic and/or immunomodulatory activity of denosumab in early BC and to identify biomarkers of response. Methods: Patients with early stage HER2-negative BC, candidates to tumor excision as first therapeutic approach were included. Patients were randomized 2: 1 to denosumab (two doses of 120mg/Kg subcutaneous denosumab, days 1 and 8 plus oral calcium 1000 mg daily for a month) and control arm (no treatment). Blood and tumor samples were collected at baseline and at surgery (2-4 weeks later). Putative changes in tumor cell proliferation by Ki67 immunohistochemistry (IHC), survival by Cleaved caspase-3 IHC and tumor infiltrating lymphocytes (TILs) quantified in H&E were evaluated between initial biopsy and surgery. RANK and RANKL expression will be analysed by IHC and the infiltrating immune populations will be characterized by specific antibodies (CD3, CD4, CD8, CD20, FoxP3, CD68, PDL1, PD1). We will analyse denosumab driven gene expression changes in tumor samples and tools such as CIBERSORT will be used to characterize the immune infiltrate. To assess the increase in TILs and the variation in Ki 67 and Cleaved caspase-3, the T-test for paired samples was used. A value of p less than 0.05 was defined as statistically significant. Result: We present results from the initial 45 patients enrolled out of 60, 31 cases in the experimental arm and 13 in the control arm. Mean age was 55,97 (range 37-88) years. 38 women with luminal breast cancer were analysed and 7 cases of triple negative BC (5 in experimental arm and 2 in control arm). Clinical and tumor characteristics were well balanced between both groups. No relevant toxicities were reported. There was no reduction of Ki67 in either of the two arms and no changes in Cleaved caspase-3 were observed. Interestingly, a statistically significant increase in TILs was observed in the denosumab treated group (p=0.0092, Paired t test) but not in the control group (p=0.68). 29.03% of patients treated with denosumab showed a ≥10% increase in TILs vs 7.14% in the control group (p=0.13). Denosumab was associated with an effective systemic inhibition of RANKL. No relationship was found between serum RANKL levels at baseline and response to denosumab. RNAseq analysis and immunophenotyping is still in progress. Conclusion: Short term neoadjuvant denosumab induces an immunomodulatory effect with an increase in stromal TILs in early BC. ClinicalTrials.gov Identifier: NCT03691311

Table 1.ResultsBiopsySurgeryKi 67 (mean frequency) Control24.5729.57Ki 67 (mean frequency) Experimental22.3927.90Cleaved caspase 3 (mean area) Control0.260.58Cleaved caspase 3 (mean area) Experimental0.350.42TILs (mean percentage) Control9.3410.29TILs (mean percentage) Experimental8.2913.54TILs incrementControl p=0.68 vs. Experimental p=0.009

Citation Format: Andrea Vethencourt, Eva M Trinidad, Anna Petit, María T Soler-Monsó, Clara Gómez Aleza, Ander Urruticochea, Amparo García-Tejedor, Anna Gumà Martinez, Veronica Obadia, Silvia Vazquez, Rafael Villanueva, Adela Fernánez, Monica Cejuela, Sabela Recalde Penabad, Agostina Stradella, Miguel Gil-Gil, Sonia Pernas, Eva Gonzalez-Suarez, Catalina Falo. First results of the randomized window of opportunity clinical trial D-Biomark: Immunomodulatory effect of denosumab in early breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-08-10.

Inhibition of RANK signaling in breast cancer induces an anti-tumor immune response orchestrated by CD8+ T cells

Most breast cancers exhibit low immune infiltration and are unresponsive to immunotherapy. We hypothesized that inhibition of the receptor activator of nuclear factor-κB (RANK) signaling pathway may enhance immune activation. Here we report that loss of RANK signaling in mouse tumor cells increases leukocytes, lymphocytes, and CD8⁺ T cells, and reduces macrophage and neutrophil infiltration. CD8⁺ T cells mediate the attenuated tumor phenotype observed upon RANK loss, whereas neutrophils, supported by RANK-expressing tumor cells, induce immunosuppression. RANKL inhibition increases the anti-tumor effect of immunotherapies in breast cancer through a tumor cell mediated effect. Comparably, pre-operative single-agent denosumab in premenopausal early-stage breast cancer patients from the Phase-II D-BEYOND clinical trial (NCT01864798) is well tolerated, inhibits RANK pathway and increases tumor infiltrating lymphocytes and CD8⁺ T cells. Higher RANK signaling activation in tumors and serum RANKL levels at baseline predict these immune-modulatory effects. No changes in tumor cell proliferation (primary endpoint) or other secondary endpoints are observed. Overall, our preclinical and clinical findings reveal that tumor cells exploit RANK pathway as a mechanism to evade immune surveillance and support the use of RANK pathway inhibitors to prime luminal breast cancer for immunotherapy.

Receptor activator of nuclear factor-κB (RANK)/RANK-ligand (RANKL) signaling regulates the tumor-immune crosstalk. Here the authors show that systemic RANKL inhibition promotes CD8 + T cell infiltration in patients with early breast cancer and that loss of RANK signaling in tumor cells drives a T cell-dependent anti-tumor response in preclinical models.

Chromosome 12p Amplification in Triple-Negative/BRCA1-Mutated Breast Cancer Associates with Emergence of Docetaxel Resistance and Carboplatin Sensitivity

Taxanes are the mainstay of treatment in triple-negative breast cancer (TNBC), with de novo and acquired resistance limiting patient's survival. To investigate the genetic basis of docetaxel resistance in TNBC, exome sequencing was performed on matched TNBC patient-derived xenografts (PDX) sensitive to docetaxel and their counterparts that developed resistance in vivo upon continuous drug exposure. Most mutations, small insertions/deletions, and copy number alterations detected in the initial TNBC human metastatic samples were maintained after serial passages in mice and emergence of resistance. We identified a chromosomal amplification of chr12p in a human BRCA1-mutated metastatic sample and the derived chemoresistant PDX, but not in the matched docetaxel-sensitive PDX tumor. Chr12p amplification was validated in a second pair of docetaxel-sensitive/resistant BRCA1-mutated PDXs and after short-term docetaxel treatment in several TNBC/BRCA1-mutated PDXs and cell lines, as well as during metastatic recurrence in a patient with BRCA1-mutated breast cancer who had progressed on docetaxel treatment. Analysis of clinical data indicates an association between chr12p amplification and patients with TNBC/basal-like breast cancer, a BRCA1 mutational signature, and poor survival after chemotherapy. Detection of chr12p amplification in a cohort of TNBC PDX models was associated with an improved response to carboplatin. Our findings reveal tumor clonal dynamics during chemotherapy treatments and suggest that a preexisting population harboring chr12p amplification is associated with the emergence of docetaxel resistance and carboplatin responsiveness in TNBC/BRCA1-mutated tumors. SIGNIFICANCE: Chr12p copy number gains indicate rapid emergence of resistance to docetaxel and increased sensitivity to carboplatin, therefore sequential docetaxel/carboplatin treatment could improve survival in TNBC/BRCA1 patients. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/79/16/4258/F1.large.jpg.

EphrinA4 plays a critical role in α4 and αL mediated survival of human CLL cells during extravasation

A role of endothelial cells in the survival of CLL cells during extravasation is presently unknown. Herein we show that CLL cells but not normal B cells can receive apoptotic signals through physical contact with TNF-α activated endothelium impairing survival in transendothelial migration (TEM) assays. In addition, the CLL cells of patients having lymphadenopathy (LApos) show a survival advantage during TEM that can be linked to increased expression of α4 and αL integrin chains. Within this context, ephrinA4 expressed on the surface of CLL cells sequestrates integrins and inactivates them resulting in reduced adhesion and inhibition of apoptotic/survival signals through them. In agreement, ephrinA4 silencing resulted in increased survival of CLL cells of LApos patients but not LA neg patients. Similarly was observed when a soluble ephrinA4 isoform was added to TEM assays strongly suggesting that accumulation of this isoform in the serum of LApos patients could contribute to CLL cells dissemination and survival in vivo. In supporting, CLL lymphadenopathies showed a preferential accumulation of apoptotic CLL cells around high endothelial venules lacking ephrinA4. Moreover, soluble ephrinA4 isolated from sera of patients increased the number and viability of CLL cells recovered from the lymph nodes of adoptively transferred mice. Finally, we present evidence suggesting that soluble ephrinA4 mediated survival during TEM could enhance a transcellular TEM route of the CLL cells. Together these findings point to an important role of ephrinA4 in the nodal dissemination of CLL cells governing extravasation and survival.

RANK Signaling Blockade Reduces Breast Cancer Recurrence by Inducing Tumor Cell Differentiation

RANK expression is associated with poor prognosis in breast cancer even though its therapeutic potential remains unknown. RANKL and its receptor RANK are downstream effectors of the progesterone signaling pathway. However, RANK expression is enriched in hormone receptor negative adenocarcinomas, suggesting additional roles for RANK signaling beyond its hormone-dependent function. Here, to explore the role of RANK signaling once tumors have developed, we use the mouse mammary tumor virus-Polyoma Middle T (MMTV-PyMT), which mimics RANK and RANKL expression patterns seen in human breast adenocarcinomas. Complementary genetic and pharmacologic approaches demonstrate that therapeutic inhibition of RANK signaling drastically reduces the cancer stem cell pool, decreases tumor and metastasis initiation, and enhances sensitivity to chemotherapy. Mechanistically, genome-wide expression analyses show that anti-RANKL therapy promotes lactogenic differentiation of tumor cells. Moreover, RANK signaling in tumor cells negatively regulates the expression of Ap2 transcription factors, and enhances the Wnt agonist Rspo1 and the Sca1-population, enriched in tumor-initiating cells. In addition, we found that expression of TFAP2B and the RANK inhibitor, OPG, in human breast cancer correlate and are associated with relapse-free tumors. These results support the use of RANKL inhibitors to reduce recurrence and metastasis in breast cancer patients based on its ability to induce tumor cell differentiation. Cancer Res; 76(19); 5857-69. ©2016 AACR.

Abstract 4389: Therapeutic opportunities of RANK pathway in breast cancer

RANK pathway, key in bone remodeling and metastasis, is essential for mammary gland development. Using genetic mouse models we have previously shown that RANKL is the main mediator of the protumorigenic role of progesterone in the mouse mammary gland. RANK overexpression in non-transformed human mammary cell lines induces epithelial to mesenchymal transition and stemness, and promotes tumorigenesis and metastasis in breast cancer lines. RANK is expressed in a subset of basal and luminal human adenocarcinomas.

Our goal is to determine a putative association of RANK and RANKL expression in breast adenocarcinomas with clinical parameters and to evaluate the functional role of RANK signaling using patient derived orthoxenografts of breast cancer. We have analyzed RANK and RANKL expression levels in an extensive collection of human breast adenocarcinomas collected from multiple centers, enriched in metastatic tumor samples. From the 318 patients with breast adenocarcinomas 138 developed metastasis. RANK expression is found on tumor cells but also on stromal cells, including tumor associated macrophages. RANKL is strongly expressed in some tumors, although the frequency is low. Analyses of RANK and RANKL mRNA and protein expression has been performed in multiple models of patient derived breast orthoxenografts. Several models with variable levels of RANK as well as RANKL expression have been identified and established in the laboratory. Functionality of the pathway was corroborated analyzing NF-kB activation upon in vitro and in vivo treatments with RANKL, in order to activate RANK signaling, or with RANK-Fc to inhibit it. We found that RANKL treatment induced NF-kB activation even in tumor cells with low levels of RANK expression.

Citation Format: Hector Perez Montoyo, Jorge Gomez Miragaya, Eva M. Trinidad, Antonio Martinez-Aranda, Maria Teresa Soler Monso, Anna Petit, Angels Sierra, Eva Gonzalez Suarez. Therapeutic opportunities of RANK pathway in breast cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4389.

Rankl Impairs Lactogenic Differentiation Through Inhibition of the Prolactin/Stat5 Pathway at Midgestation

Prolactin and progesterone both orchestrate the proliferation and differentiation of the mammary gland during gestation. Differentiation of milk secreting alveoli depends on the presence of prolactin receptor, the downstream Jak2-Stat5 pathway and the transcription factor Elf5. A strict regulation of Rank signaling is essential for the differentiation of the mammary gland and in particular for alveolar commitment. Impaired alveologenesis and lactation failure are observed in both, knockout and Rank overexpressing mice; however, the underlying molecular mechanism responsible for these phenotypes remains largely unknown. Using genome-wide expression analyses and functional studies, we show here that Rankl (RL) exposure leads to impaired secretory differentiation of alveolar cells not only in MMTV-RANK but also in wild-type (WT) mammary acini. Conversely, pharmacological blockage of Rank signaling at midgestation in WT mice leads to precocious and exacerbated lactogenesis. Mechanistically, RL negatively regulates Stat5 phosphorylation and Elf5 expression at the onset of lactogenesis. Continuous RL exposure leads to the expansion of basal and bipotent cells in WT and MMTV-RANK acini. Overall, we demonstrate that enhanced Rank signaling impairs secretory differentiation during pregnancy by inhibition of the prolactin/p-Stat5 pathway.

Eph-ephrin bidirectional signaling comes into the context of lymphocyte transendothelial migration

A better knowledge of the molecular mechanisms that govern leukocyte trafficking is of major relevance for the clinics. Both normal and pathologic extravasation of lymphocytes are a fine-tuned spatio-temporal event of migratory path-finding likely regulated by molecular guidance cues underlying cell movements in other systems. We have recently reported that members of the Eph family of receptor tyrosine kinases, namely EphA2 and one of its ligands, ephrin-A4 (EFNA4) can mediate in the traffic of chronic lymphocytic leukemia (CLL) cells and presumably of normal B cells between the blood and the tissues. The importance of EphA2-EFNA4 interactions at the endothelium-lymphocyte interface during TEM could rely on their attractive/repulsive properties. In the present work, we expand on those results by including additional insights and new suggestions for future studies that discuss the relevance of these molecules in overall cell adhesion dynamic events.

Chiari I malformation redefined: clinical and radiographic findings for 364 symptomatic patients

OBJECTIVE

Chiari malformations are regarded as a pathological continuum of hindbrain maldevelopments characterized by downward herniation of the cerebellar tonsils. The Chiari I malformation (CMI) is defined as tonsillar herniation of at least 3 to 5 mm below the foramen magnum. Increased detection of CMI has emphasized the need for more information regarding the clinical features of the disorder.

METHODS

We examined a prospective cohort of 364 symptomatic patients. All patients underwent magnetic resonance imaging of the head and spine, and some were evaluated using CINE-magnetic resonance imaging and other neurodiagnostic tests. For 50 patients and 50 age- and gender-matched control subjects, the volume of the posterior cranial fossa was calculated by the Cavalieri method. The families of 21 patients participated in a study of familial aggregation.

RESULTS

There were 275 female and 89 male patients. The age of onset was 24.9+/-15.8 years (mean +/- standard deviation), and 89 patients (24%) cited trauma as the precipitating event. Common associated problems included syringomyelia (65%), scoliosis (42%), and basilar invagination (12%). Forty-three patients (12%) reported positive family histories of CMI or syringomyelia. Pedigrees for 21 families showed patterns consistent with autosomal dominant or recessive inheritance. The clinical syndrome of CMI was found to consist of the following: 1) headaches, 2) pseudotumor-like episodes, 3) a Meniere's disease-like syndrome, 4) lower cranial nerve signs, and 5) spinal cord disturbances in the absence of syringomyelia. The most consistent magnetic resonance imaging findings were obliteration of the retrocerebellar cerebrospinal fluid spaces (364 patients), tonsillar herniation of at least 5 mm (332 patients), and varying degrees of cranial base dysplasia. Volumetric calculations for the posterior cranial fossa revealed a significant reduction of total volume (mean, 13.4 ml) and a 40% reduction of cerebrospinal fluid volume (mean, 10.8 ml), with normal brain volume.

CONCLUSION

These data support accumulating evidence that CMI is a disorder of the para-axial mesoderm that is characterized by underdevelopment of the posterior cranial fossa and overcrowding of the normally developed hindbrain. Tonsillar herniation of less than 5 mm does not exclude the diagnosis. Clinical manifestations of CMI seem to be related to cerebrospinal fluid disturbances (which are responsible for headaches, pseudotumor-like episodes, endolymphatic hydrops, syringomyelia, and hydrocephalus) and direct compression of nervous tissue. The demonstration of familial aggregation suggests a genetic component of transmission.