Integrin alpha5 in human breast cancer is a mediator of bone metastasis and a therapeutic target for the treatment of osteolytic lesions

Bone metastasis remains a major cause of mortality and morbidity in breast cancer. Therefore, there is an urgent need to better select high-risk patients in order to adapt patient's treatment and prevent bone recurrence. Here, we found that integrin alpha5 (ITGA5) was highly expressed in bone metastases, compared to lung, liver, or brain metastases. High ITGA5 expression in primary tumors correlated with the presence of disseminated tumor cells in bone marrow aspirates from early stage breast cancer patients (n = 268; p = 0.039). ITGA5 was also predictive of poor bone metastasis-free survival in two separate clinical data sets (n = 855, HR = 1.36, p = 0.018 and n = 427, HR = 1.62, p = 0.024). This prognostic value remained significant in multivariate analysis (p = 0.028). Experimentally, ITGA5 silencing impaired tumor cell adhesion to fibronectin, migration, and survival. ITGA5 silencing also reduced tumor cell colonization of the bone marrow and formation of osteolytic lesions in vivo. Conversely, ITGA5 overexpression promoted bone metastasis. Pharmacological inhibition of ITGA5 with humanized monoclonal antibody M200 (volociximab) recapitulated inhibitory effects of ITGA5 silencing on tumor cell functions in vitro and tumor cell colonization of the bone marrow in vivo. M200 also markedly reduced tumor outgrowth in experimental models of bone metastasis or tumorigenesis, and blunted cancer-associated bone destruction. ITGA5 was not only expressed by tumor cells but also osteoclasts. In this respect, M200 decreased human osteoclast-mediated bone resorption in vitro. Overall, this study identifies ITGA5 as a mediator of breast-to-bone metastasis and raises the possibility that volociximab/M200 could be repurposed for the treatment of ITGA5-positive breast cancer patients with bone metastases.

Abstract 3182: Kindlin-1 expression is associated with EGFR/RAS/MAPK activation and response to MEK inhibitors in triple-negative breast cancer

Background: Triple-negative breast cancer (TNBC) accounts for ~15% of all invasive breast cancers. This heterogeneous group of tumors is the most aggressive and difficult-to-treat subtype of breast cancer. We previously demonstrated that Kindlin-1 is overexpressed in TNBC and patients with high Kindlin-1 have a worse prognosis. We determined that Kindlin-1 plays a major role in the epithelial to mesenchymal transition, tumor growth and breast cancer metastasis. TNBC have also been reported to express high levels of EGFR, in ~70% of the cases. Unfortunately, anti-EGFR therapy in TNBC fails to show a clinical benefit. In this study, we aimed to investigate a potential link between EGFR/RAS/MAPK pathway and Kindlin-1 in TNBC, and to propose new therapeutic strategies based on our findings.

Methods: First, a gene set enrichment analysis was performed in 58 breast cancer cell lines (CCLE dataset) to detect the signaling pathways differentially enriched in cells expressing high levels of Kindlin-1. We next evaluated whether Kindlin-1 expression could be associated to an increased MAPK signaling by testing the mutational status and phosphorylation of key effectors of the pathway. To determine whether Kindlin-1 could be a predictive biomarker for the response to MEK inhibitors, we assessed its expression in sensitive versus resistant cell lines. Finally, we examined in vivo the anti-tumor efficacy of Selumetinib in a series of 27 triple negative breast cancer patient derived xenografts (PDX), highly representative of the originating tumor in terms of biology and therapeutic sensitivity. These PDX models have been characterized for Kindlin-1 expression (at RNA and protein levels). The sensitivity to MEKi of the TNBC PDX models was examined with regard to their Kindlin-1 expression.

Results: Gene set enrichment analysis put in evidence that EGFR/RAS/MAPK pathway is upregulated in breast cancer cells with high Kindlin-1 expression. Although mutations are infrequent in breast cancer, an increased Kindlin-1 expression was observed in a subset of EGFR/RAS-activated cell lines (mutated or amplified). Moreover, TNBC expressing high levels of Kindlin-1 showed an increased phosphorylation of key effectors (ERK, MEK). We also demonstrated that Kindlin-1 mRNA expression was significantly increased in sensitive cell lines to different MEK inhibitors such as Trametinib (p=0.007) or Selumetinib (p=0.005) compared with resistant cells. In addition, in preclinical TNBC PDX models treated with Selumetinib there was a correlation between tumor growth inhibition and Kindlin-1 protein expression (r=0.57; p=0.017).

Conclusion: Our findings indicate that Kindlin-1 expression may be a promising predictive biomarker of MEK inhibitors response in TNBC and may offer new therapeutic opportunities for patients with limited treatment options and refractory cancer types to current treatments.

Citation Format: Paula Azorin, Florian Bonin, Zakia Tariq, Florence Coussy, Elisabetta Marangoni, Rosette Lidereau, Keltouma Driouch. Kindlin-1 expression is associated with EGFR/RAS/MAPK activation and response to MEK inhibitors in triple-negative breast cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3182.

[Biology of metastases and molecular mechanisms of their formation]

Metastasis in cancer patients is often associated with a poor prognosis. However, we still have limited knowledge of the underlying molecular mechanisms, due to the great complexity of the biological processes involved in the formation of metastases. During tumor progression, the metastatic cells acquire genetic and epigenetic modifications allowing them to adapt to the various environments they will encounter (in the circulation and the host microenvironment) and to resist to the antitumor therapeutic agents. In this review, we expose the current knowledge on the biology of metastases. We summarize the different signaling pathways involved in the successive steps of the metastatic cascade, highlighting recent advances in the field to better understand the molecular mechanisms leading to metastasis formation. In addition, our understanding of metastatic progression has made great progress with the recent advances in high throughput sequencing techniques. We expose data from genomic analyzes of metastases. These studies allowed the identification of alterations acquired exclusively in distant metastases. They highlight the emergence of alterations offering new targeted therapeutic options for cancer patients and they provide new insight into the mechanisms of treatment resistance at the origin of metastatic relapses. Finally, we present latest clinical trials based on the genomic profiles of metastases, initiated in recent years, and we discuss their potential impact in personalized medicine.

VOPP1 promotes breast tumorigenesis by interacting with the tumor suppressor WWOX

Background

The WW domain-containing oxidoreductase (WWOX) gene, frequently altered in breast cancer, encodes a tumor suppressor whose function is mediated through its interactions with cancer-related proteins, such as the pro-apoptotic protein p73α.

Results

To better understand the involvement of WWOX in breast tumorigenesis, we performed a yeast two-hybrid screen and co-immunoprecipitation assays to identify novel partners of this protein. We characterized the vesicular overexpressed in cancer pro-survival protein 1 (VOPP1) as a new regulator of WWOX. In breast cancer cells, VOPP1 sequestrates WWOX in lysosomes, impairs its ability to associate with p73α, and inhibits WWOX-dependent apoptosis. Overexpressed VOPP1 potentiates cellular transformation and enhances the growth of transplanted tumors in vivo. VOPP1 is overexpressed in breast tumors, especially in tumors that retain WWOX. Moreover, increased expression of VOPP1 is associated with reduced survival of patients with WWOX-positive, but not with WWOX-negative, tumors.

Conclusions

These findings emphasize the importance of the sequestration of WWOX by VOPP1 in addition to WWOX loss in breast tumors and define VOPP1 as a novel oncogene promoting breast carcinogenesis by inhibiting the anti-tumoral effect of WWOX.

Electronic supplementary material

The online version of this article (10.1186/s12915-018-0576-6) contains supplementary material, which is available to authorized users.

The iron chelator deferasirox synergises with chemotherapy to treat triple-negative breast cancers

To ensure their high proliferation rate, tumor cells have an iron metabolic disorder causing them to have increased iron needs, making them more susceptible to iron deprivation. This vulnerability could be a therapeutic target. In breast cancers, the development of new therapeutic approaches is urgently needed for patients with triple-negative tumors, which frequently relapse after chemotherapy and suffer from a lack of targeted therapies. In this study, we demonstrated that deferasirox (DFX) synergises with standard chemotherapeutic agents such as doxorubicin, cisplatin and carboplatin to inhibit cell proliferation and induce apoptosis and autophagy in triple-negative breast cancer (TNBC) cells. Moreover, the combination of DFX with doxorubicin and cyclophosphamide delayed recurrences in breast cancer patient-derived xenografts without increasing the side-effects of chemotherapies alone or altering the global iron storage of mice. Antitumor synergy of DFX and doxorubicin seems to involve downregulation of the phosphoinositide 3-kinase and nuclear factor-κB pathways. Iron deprivation in combination with chemotherapy could thus help to improve the effectiveness of chemotherapy in TNBC patients without increasing toxicity. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Abstract 4303: Vopp1 physically interacts with Wwox and inhibits its apoptotic function in breast cancer

WWOX is a tumor suppressor gene spanning the fragile site FRA16D and targeted by loss of heterozygosity or homozygous deletion in several tumor types. Wwox protein consists of two N-terminal WW domains that mediate protein-protein interactions and a C-terminal short-chain Dehydrogenase/Reductase domain (SDR). The WW1 module acts as a versatile platform linking WWOX with numerous multiprotein complexes. Thus, Wwox suppressor activity relies on its binding capacities to various partners. Wwox has been shown to interact with known proto-oncogenes such as p73, deltaNp63, AP2γ, c-jun, Erbb4, c-Met, Runx2 and Dvl-2. At the cellular level, Wwox has been shown to be a pro-apoptotic protein that induces cell death by acting in both the nucleus and cytoplasm. More recently, emerging evidence also suggest an important role of WWOX in DNA damage response. By using a yeast two-hybrid system and co-immunoprecipitation assays, we characterized Vopp1 (Vesicular Over-expressed in cancer Pro-survival Protein 1) as a new molecular partner of the tumor suppressor Wwox. VOPP1 gene localizes at the frequently amplified 7p11.2 locus and is often co-amplified with EGFR. It is overexpressed in multiple malignancies such as glioblastoma, gastric, head and neck and lung cancers. In this study, we demonstrate that VOPP1 physically interacts with Wwox in breast cancer cells. Upon binding, Wwox is recruited to the Vopp1-containing lysosomal compartment. This recruitment inhibits Wwox-mediated apoptosis at least in part by preventing Wwox-p73 interaction. In addition, Vopp1 acts as an oncogene as shown by its capacity to potentiate cellular transformation. Moreover, in breast cancer clinical samples, VOPP1 overexpression was detected predominantly in tumors retaining Wwox expression. Vopp1 overexpression is associated to a reduced survival of breast cancer patients, especially patients with luminal B tumor types. Remarkably, the VOPP1/WWOX expression ratio showed a significantly worst prognosis outperforming either gene alone. These findings highlight the importance of Wwox compartimentation in addition to Wwox loss in human cancer pathogenesis and define Vopp1 as a novel negative regulator of Wwox whose overexpression induces breast carcinogenesis by affecting the tumor suppressive activity of Wwox.

Citation Format: François Lallemand, Florian Bonin, Rosette Lidereau, Keltouma Driouch. Vopp1 physically interacts with Wwox and inhibits its apoptotic function in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4303. doi:10.1158/1538-7445.AM2017-4303

A patient with severe respiratory failure caused by novel human coronavirus

We report a case of a 45-year-old patient who developed severe acute respiratory distress syndrome accompanied by renal failure. An infection with a novel human coronavirus was confirmed and found to be the reason for rapidly progressive respiratory failure of our patient.

Contact investigation of a case of human novel coronavirus infection treated in a German hospital, October-November 2012

On 24 October 2012, a patient with acute respiratory distress syndrome of unknown origin and symptom onset on 5 October was transferred from Qatar to a specialist lung clinic in Germany. Late diagnosis on 20 November of an infection with the novel Coronavirus (NCoV) resulted in potential exposure of a considerable number of healthcare workers. Using a questionnaire we asked 123 identified contacts (120 hospital and three out-of-hospital contacts) about exposure to the patient. Eighty-five contacts provided blood for a serological test using a two-stage approach with an initial immunofluorescence assay as screening test, followed by recombinant immunofluorescence assays and a NCoV-specific serum neutralisation test. Of 123 identified contacts nine had performed aerosol-generating procedures within the third or fourth week of illness, using personal protective equipment rarely or never, and two of these developed acute respiratory illness. Serology was negative for all nine. Further 76 hospital contacts also tested negative, including two sera initially reactive in the screening test. The contact investigation ruled out transmission to contacts after illness day 20. Our two-stage approach for serological testing may be used as a template for similar situations.

Contact investigation of a case of human novel coronavirus infection treated in a German hospital, October-November 2012

On 24 October 2012, a patient with acute respiratory distress syndrome of unknown origin and symptom onset on 5 October was transferred from Qatar to a specialist lung clinic in Germany. Late diagnosis on 20 November of an infection with the novel Coronavirus (NCoV) resulted in potential exposure of a considerable number of healthcare workers. Using a questionnaire we asked 123 identified contacts (120 hospital and three out-of-hospital contacts) about exposure to the patient. Eighty-five contacts provided blood for a serological test using a two-stage approach with an initial immunofluorescence assay as screening test, followed by recombinant immunofluorescence assays and a NCoV-specific serum neutralisation test. Of 123 identified contacts nine had performed aerosol-generating procedures within the third or fourth week of illness, using personal protective equipment rarely or never, and two of these developed acute respiratory illness. Serology was negative for all nine. Further 76 hospital contacts also tested negative, including two sera initially reactive in the screening test. The contact investigation ruled out transmission to contacts after illness day 20. Our two-stage approach for serological testing may be used as a template for similar situations.

Assays for laboratory confirmation of novel human coronavirus (hCoV-EMC) infections

We present a rigorously validated and highly sensitive confirmatory real-time RT-PCR assay (1A assay) that can be used in combination with the previously reported upE assay. Two additional RT-PCR assays for sequencing are described, targeting the RdRp gene (RdRpSeq assay) and N gene (NSeq assay), where an insertion/deletion polymorphism might exist among different hCoV-EMC strains. Finally, a simplified and biologically safe protocol for detection of antibody response by immunofluorescence microscopy was developed using convalescent patient serum.

A methodological approach to unravel organ-specific breast cancer metastasis

Breast cancer is the most commonly diagnosed and the second highest cause of cancer-related mortality. Although major breakthroughs have emerged during the past decades concerning the characterization of major malignant tumors hallmarks, little is known about the molecular process that sustains the most deadly feature of cancer: metastasis to distant organs. In fact, this colonization of tumor cells to secondary sites is not random but rather orientated, and depends on several signalling events that are not fully elucidated yet. Understanding the precise molecular and cellular mechanisms accountable for the specific invasion of tissues by breast cancer cells is likely to be important for developing new therapeutic strategies to effectively prevent metastasis in patients diagnosed with early cancer lesions. Here, we briefly describe a multidisciplinary approach based on the molecular profiling of breast cancer metastases, the elaboration of prognostic gene signatures, the clinical validation and the experimental confirmation using cell and animal models to better address breast cancer metastasis. This methodology can be considered as a useful workflow to identify and validate the genes that trigger and support organ tropism of breast cancer cells during metastasis.

Confounding effects in "a six-gene signature predicting breast cancer lung metastasis": reply

Molecular signatures have begun to elucidate the biological and molecular mechanisms underlying the phenotypic diversity of breast tumors. Breast tumors are characterized by five different molecular subtypes that are associated with distinct clinical outcomes in terms of prognosis, treatment response, and site of relapse. In particular, the basal-like and luminal B subtypes of tumors are more aggressive and have a higher tendency to metastasize to the lung than do the other subtypes. Given this difference in metastatic profiles of breast tumors, the six-gene signature (6GS) that we showed to be predictive of lung relapse was reexamined in the context of the tumor subtypes. This first analysis suggested that the 6GS is a surrogate for molecular subtype, discriminating basal-like tumors rather than tumors that metastasize to the lung. Here, we show that the 6GS discriminates the two overlapping features, the basal-like subtype and the tendency to metastasize to the lung. Nevertheless, the 6GS predicts lung metastases of breast tumors independent of the molecular subtypes.

GATA3 is a master regulator of the transcriptional response to low-dose ionizing radiation in human keratinocytes

BACKGROUND

The general population is constantly exposed to low levels of radiation through natural, occupational or medical irradiation. Even if the biological effects of low-level radiation have been intensely debated and investigated, the molecular mechanisms underlying the cellular response to low doses remain largely unknown.

RESULTS

The present study investigated the role of GATA3 protein in the control of the cellular and molecular response of human keratinocytes exposed to a 1 cGy dose of X-rays. Chromatin immunoprecipitation showed GATA3 to be able to bind the promoter of 4 genes responding to a 1 cGy exposure. To go further into the role of GATA3 after ionizing radiation exposure, we studied the cellular and molecular consequences of radiation in GATA3 knock-down cells. Knock-down was obtained by lentiviral-mediated expression of an shRNA targeting the GATA3 transcript in differentiated keratinocytes. First, radiosensitivity was assessed: the toxicity, in terms of immediate survival (with XTT test), associated with 1 cGy radiation was found to be increased in GATA3 knock-down cells. The impact of GATA3 knock-down on the transcriptome of X-ray irradiated cells was also investigated, using oligonucleotide microarrays to assess changes between 3 h and 72 h post-irradiation in normal vs GATA3 knock-down backgrounds; transcriptome response was found to be completely altered in GATA3 knock-down cells, with a strong induction/repression peak 48 h after irradiation. Functional annotation revealed enrichment in genes known to be involved in chaperone activity, TGFbeta signalling and stress response.

CONCLUSION

Taken together, these data indicate that GATA3 is an important regulator of the cellular and molecular response of epidermal cells to very low doses of radiation.

[Pure coronary spasm: autonomic disease or form of onset of atheroma? Contribution of repeat coronarography in 23 patients]

Coronary spasm has often been blamed for facilitating the development of atheroma, but some authors regard it as a separate disease. In order to form an opinion on these two theories, we performed repeat coronary arteriography at an interval of 4 years on average in 23 patients: 19 men and 4 women aged from 38 to 62 years (mean: 49,4 years). At the initial examination the coronary vessels were normal in 11 patients and showed irregular arterial walls without significant stenosis in 12 patients. Coronary spasm was demonstrated directly in 17 cases (6 spontaneous spasms during arteriography and 11 induced spasms) and indirectly in 6 cases (ECG signs of ischaemia during the anginal attack). At the second coronary arteriography we found that the spasms persisted, with positive response to a challenge test in 17 out of the 19 patients tested. The challenge test was not performed in 4 patients who had developed significant lesions. The vessels themselves were altered in 6 patients, with images of occlusion (2 cases), stenosis (2 cases), parietal irregularities (1 case) and aneurysm (1 case) appearing on spastic arteries, and images of stenosis in 2 patients with apparently non-spastic arteries. There was no difference in age, sex, risk factors, initial coronary status and time interval between arteriographies between these 6 patients and the 17 patients whose coronary arteries had remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)