ONC201 in combination with paxalisib for the treatment of H3K27-altered diffuse midline glioma

Diffuse midline gliomas (DMG), including diffuse intrinsic pontine gliomas (DIPGs), are the most lethal of childhood cancers. Palliative radiotherapy is the only established treatment, with median patient survival of 9-11 months. ONC201 is a DRD2 antagonist and ClpP agonist that has shown preclinical and emerging clinical efficacy in DMG. However, further work is needed to identify the mechanisms of response of DIPGs to ONC201 treatment and to determine whether recurring genomic features influence response. Using a systems-biological approach, we showed that ONC201 elicits potent agonism of the mitochondrial protease ClpP to drive proteolysis of electron transport chain and tricarboxylic acid cycle proteins. DIPGs harboring PIK3CA-mutations showed increased sensitivity to ONC201, while those harboring TP53-mutations were more resistant. Metabolic adaptation and reduced sensitivity to ONC201 was promoted by redox-activated PI3K/Akt signaling, which could be counteracted using the brain penetrant PI3K/Akt inhibitor, paxalisib. Together, these discoveries coupled with the powerful anti-DIPG/DMG pharmacokinetic and pharmacodynamic properties of ONC201 and paxalisib have provided the rationale for the ongoing DIPG/DMG phase II combination clinical trial NCT05009992.

EXTH-12. PRECLINICAL AND CASE STUDY EXAMINATION OF THE COMBINATION OF THE CLPP AGONIST ONC201 WITH THE PI3K/AKT INHIBITOR PAXALISIB FOR THE TREATMENT OF DIFFUSE MIDLINE GLIOMA

Diffuse midline gliomas (DMGs), including those of the pons (diffuse intrinsic pontine glioma - DIPG), are pediatric CNS tumors recognized as the most lethal of all children’s cancers. Palliative radiotherapy remains the only approved treatment, with survival just 9-11 months post-diagnosis. The brain-penetrant small molecule therapy, ONC201, shows preclinical and emerging efficacy in early-stage clinical trials. However, patients invariably develop resistance, with some patients and models completely refractory to treatment. Using a powerful combination of pharmacology, proteomics, genomics, epigenetics, in vitro and in vivo modeling, across ten international laboratories, we have uncovered mechanisms underpinning resistance to ONC201. We find ONC201 elicits antagonism of the Dopamine receptor D2 (DRD2), whilst also causing mitochondrial degradation through potent agonism of the mitochondrial protease CLPP. This drives proteolysis of the electron transport chain (ETC) proteins including Succinate dehydrogenase A (SDHA) and the critical mitochondrial tricarboxylic acid (TCA) cycle regulator, Isocitrate dehydrogenase 3B (IDH3B). Loss of TCA activity reduces α-ketoglutarate and inhibits lysine demethylation, increasing methylation of H3K4me3 and H3K27me3, thus, altering the epigenome of DIPG. Mitochondrial disruption elicited redox-activated RAS-PI3K/AKT signaling, counteracted using the PI3K/AKT inhibitor paxalisib. The combination of ONC201 and paxalisib synergistically extended survival of two aggressive DIPG PDX models (SU-DIPG-VI vehicle=73 vs. combination=100-days, p=0.0027; SF8626 vehicle=36 vs. combination=43-days, p=0.0002). Compassionate access to this combination (n=2 patients; immediately post-RT and following re-RT) resulted in dramatic reductions in tumor volume, extending overall survival for the patient at diagnosis and the patient at progression (e.g., MR axial diagnosis scan = 1554 mm2, following twelve months on the combination, current tumor volume = 464 mm2 (~70% reduction), patient remains in progression free survival, 15 months since diagnosis). The clinical utility of our preclinical data is currently under investigation in the PNOC022 clinical trial (NCT05009992).

Tumor-Infiltrating Lymphocytes (TILs) in Epithelial Ovarian Cancer: Heterogeneity, Prognostic Impact, and Relationship with Immune Checkpoints

Epithelial ovarian cancers (EOC) are often diagnosed at an advanced stage with carcinomatosis and a poor prognosis. First-line treatment is based on a chemotherapy regimen combining a platinum-based drug and a taxane-based drug along with surgery. More than half of the patients will have concern about a recurrence. To improve the outcomes, new therapeutics are needed, and diverse strategies, such as immunotherapy, are currently being tested in EOC. To better understand the global immune contexture in EOC, several studies have been performed to decipher the landscape of tumor-infiltrating lymphocytes (TILs). CD8+ TILs are usually considered effective antitumor immune effectors that immune checkpoint inhibitors can potentially activate to reject tumor cells. To synthesize the knowledge of TILs in EOC, we conducted a review of studies published in MEDLINE or EMBASE in the last 10 years according to the PRISMA guidelines. The description and role of TILs in EOC prognosis are reviewed from the published data. The links between TILs, DNA repair deficiency, and ICs have been studied. Finally, this review describes the role of TILs in future immunotherapy for EOC.

A Bloody Conspiracy. Blood Vessels and Immune Cells in the Tumor Microenvironment

Simple Summary

The tumor microenvironment has risen over the last years as a significant contributor to the failure of antitumoral strategies due to its numerous pro-tumorigenic activities. In this review, we focused on two features of this microenvironment, namely angiogenesis and immunity, which have been the targets of therapies to tackle tumors via its microenvironmental part over the last decade. Increasing our knowledge of the complex interactions within this ecosystem is mandatory to optimize these therapeutic approaches. The development of innovative experimental models is of great help in reaching this goal.

Abstract

Cancer progression occurs in concomitance with a profound remodeling of the cellular microenvironment. Far from being a mere passive event, the re-orchestration of interactions between the various cell types surrounding tumors highly contributes to the progression of the latter. Tumors notably recruit and stimulate the sprouting of new blood vessels through a process called neo-angiogenesis. Beyond helping the tumor cope with an increased metabolic demand associated with rapid growth, this also controls the metastatic dissemination of cancer cells and the infiltration of immune cells in the tumor microenvironment. To decipher this critical interplay for the clinical progression of tumors, the research community has developed several valuable models in the last decades. This review offers an overview of the various instrumental solutions currently available, including microfluidic chips, co-culture models, and the recent rise of organoids. We highlight the advantages of each technique and the specific questions they can address to better understand the tumor immuno-angiogenic ecosystem. Finally, we discuss this development field’s fundamental and applied perspectives.

Abstract 1671: Engineering new cellular models to decipher H3.3K27M mutation role in DIPGs' resistance to therapies

Among pediatric brain tumors, Diffuse Intrinsic Pontine Gliomas (DIPGs) display a particularly dismal prognosis, highlighted by their median survival lower than one year. Indeed, DIPGs’ location and infiltrative properties preclude their surgical resection. Moreover, DIPGs poorly respond to chemotherapeutic agents. In this context, the only treatment for these tumors remains palliative radiotherapy, systematically followed by tumor progression. In addition to their resistance to therapies, DIPGs are characterized by recurrent histone H3 mutations. The H3.3K27M mutation is the most frequent and results from a heterozygous single nucleotide variant in the H3F3A gene, inducing the lysine 27 substitution by a methionine. Although H3.3K27M’s driver role in DIPGs tumorigenesis is now established, its role in their chemo- and radioresistance remains unclear. Aiming to decipher the potential role of this mutation in pediatric gliomas’ resistance to therapies, we established isogenic cellular models of H3.3K27M induction and reversion.We first induced H3.3K27M mutation in three initially non-mutated supratentorial pediatric glioma cell lines. Thus, we generated models that stably expressed the dominant-negative H3.3K27M or the wild type H3.3 as controls. Complementarily, to study H3.3K27M roles in a DIPG cell context, we also developed H3.3K27M reversion models in two initially mutated DIPG cell lines by applying a gene-editing strategy based on the combinatorial use of the CRISPR/Cas9 technology and an insert.We showed that H3.3K27M induction in Res259 and KNS42 cells conferred a radioresistant phenotype to a fractionated radiotherapy schedule. Besides, we performed a screening of 80 anti-cancer drugs, which revealed a differential impact of the mutation on the drug sensitivity profiles of our three H3.3K27M-induced cell lines. These results indicate that H3.3K27M can control pediatric glioma cells’ resistance to therapies, but in a heterogeneous way depending on the cellular context. Along this line, we are currently characterizing the chemo- and radiotherapy response of our new DIPG H3.3K27M-reversed models. Altogether, our first results support a role for H3.3K27M in pediatric gliomas resistance to treatments, and our complementary models pave the way for identifying new H3.3K27M-dependent mechanisms and promising targets to sensitize DIPGs to therapies.

Citation Format: Andria Rakotomalala, Paul Lewandowski, Quentin Bailleul, Clara Savary, Mélanie Arcicasa, Christine Bal, Maud Hamadou, Paul Huchedé, Audrey Restouin, Remy Castellano, Yves Collette, Audrey Vincent, Pierre-Olivier Angrand, Eric Adriaenssens, Xuefen Le Bourhis, Pierre Leblond, Marie Castets, Eddy Pasquier, Alessandro Furlan, Samuel Meignan. Engineering new cellular models to decipher H3.3K27M mutation role in DIPGs' resistance to therapies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1671.

DIPG-07. Preclinical and case study results underpinning the phase II clinical trial testing the combination of ONC201 and paxalisib for the treatment of patients with diffuse midline glioma (NCT05009992)

Diffuse midline gliomas (DMG), including those of the brainstem (diffuse intrinsic pontine glioma - DIPG), are pediatric CNS tumors recognized as the most lethal of all children’s cancers. Palliative radiotherapy is the only approved treatment, with survival just 9-11–months post-diagnosis. ONC201 shows preclinical and emerging clinical efficacy in early-stage clinical trials, extending survival of DIPG patients by ~9-11–months compared to historic controls. However, patients invariably develop resistance, with some patients completely refractory to treatment. Using a multi-omics approach, including pharmacology, proteomics, genomics, epigenetics, in vitro and in vivo modeling, across ten international laboratories, we have uncovered the inherent mechanisms of resistance to ONC201. We find ONC201 elicits antagonism of the Dopamine receptor D2 (DRD2), whilst also causing mitochondrial degradation through potent agonism of the Mitochondrial protease CLPP, that drives proteolysis of the electron transport chain (ETC) protein Succinate dehydrogenase A (SDHA) and degradation of critical mitochondrial tricarboxylic acid (TCA) cycle regulator Isocitrate dehydrogenase 3B (IDH3B). Loss mitochondrial respiration increased hypoxia and reduced α-ketoglutarate, inhibiting lysine demethylation, increasing methylation of H3K4me3 and H3K27me3, thus altering the epigenome of primary DIPG cells. Loss of SDHA caused oxidation of succinate forming superoxide driving redox regulated PI3K/AKT signaling, counteracted using the PI3K/AKT inhibitor paxalisib. The combination of ONC201 and paxalisib synergically extended survival of two aggressive DIPG PDX models (SU-SIPG-VI vehicle=73 vs. combination=100-days, p=0.0027; SF8626 vehicle=36 vs. combination=43-days, p=0.0002). Compassionate access to this combination (n=2 patients; immediately post-RT and following re-RT) resulted in reductions in tumor volume and complete resolution of disease symptoms, extending overall survival (e.g., diagnosis patient MR axial scan=1554 mm2 , following eight months on the combination, current tumor volume=464 mm2 (<70%), patient remains on treatment). Our findings harness the powerful anti-DMG/DIPG pharmacokinetic/dynamic properties of ONC201 and paxalisib, a combination that is currently in clinical trials (NCT05009992).

[The art of war as applied to pediatric gliomas: Know your enemy]

Pediatric brain cancers represent the most frequent solid tumors and the leading cause of cancer-driven mortality in children. Pediatric High Grade Gliomas display a very poor prognosis. Among these, DIPG (Diffuse Intrinsic Pontine Gliomas), localized to the brain stem, cannot benefit from a total exeresis due to this critical location and to their highly infiltrating nature. Radiotherapy remains the standard treatment against these tumors for almost five decades, and attempts to improve the prognosis of patients with chemotherapy or targeted therapies have failed. Thanks to the rise of high throughput sequencing, the knowledge of molecular alterations in pediatric gliomas strongly progressed and allowed to highlight distinct biomolecular entities and to establish more accurate diagnoses. In this review, we summarize this new information and the perspectives that it brings for clinical strategies.

Hypoxia in Solid Tumors: How Low Oxygenation Impacts the "Six Rs" of Radiotherapy

Radiotherapy is an important component of cancer treatment, with approximately 50% of all cancer patients receiving radiation therapy during their course of illness. Nevertheless, solid tumors frequently exhibit hypoxic areas, which can hinder therapies efficacy, especially radiotherapy one. Indeed, hypoxia impacts the six parameters governing the radiotherapy response, called the « six Rs of radiation biology » (for Radiosensitivity, Repair, Repopulation, Redistribution, Reoxygenation, and Reactivation of anti-tumor immune response), by inducing pleiotropic cellular adaptions, such as cell metabolism rewiring, epigenetic landscape remodeling, and cell death weakening, with significant clinical repercussions. In this review, according to the six Rs, we detail how hypoxia, and associated mechanisms and pathways, impact the radiotherapy response of solid tumors and the resulting clinical implications. We finally illustrate it in hypoxic endocrine cancers through a focus on anaplastic thyroid carcinomas.

Abstract 5005: Impact of H3.3K27M mutation on diffuse intrinsic pontine glioma's resistance to treatment

Diffuse Intrinsic Pontine Glioma is one of the worst pediatric brain tumors regarding prognosis due notably to intrinsic cell resistance to radio and chemotherapy. One of the main characteristics of DIPG cells is the presence of a mono-allelic mutation on the lysine 27 of histone H3 (H3K27M). This mutation inhibits the trimethylation of this lysine that leads to strong modifications of gene expression. Until now, even though this mutation seems to be a driver event in tumorigenesis, its role in cell resistance to treatment has not been deciphered, due to a lack of relevant cellular models. This way, in order to evaluate the role of the mutation on resistance to treatment, we first induced the mutation in three H3K27-unmutated pediatric glioma cell lines. In parallel, using the CRISPR/Cas9 technology, we are establishing DIPG cellular models in which the mutation will be reversed. By gene trapping approach, we aim to restore an H3F3Awt/wt genotype. After validation, these models would result in original tools to study the impact of H3K27M mutation in DIPG cells resistance to treatment. For the model of induction, the transfected cell lines exhibit the mutation accompanied by a loss of H3K27me3 mark and H3.3 overexpression. For now, we showed an increased cell growth due to the mutation in two cell lines, under normoxia as well as under hypoxia. On contrary there was no impact on resistance to chemotherapy or ionizing radiation. In the third cell line, we didn't observe any impact on cell growth, but an increase of cell radioresistance. Concerning the mutation reversion, our preliminary results show homologous recombination at the right locus in the genome, and some clones present a loss of the mutation confirmed by sequencing. After the removal of resistance cassette by action of a recombinase protein, we will be able to evaluate the biological effects of mutation reversion. To sum up, these different models would allow us to decipher cellular and molecular mechanism induced by the H3.3K27M mutation in DIPG cells including resistance to treatment, and thus, to possibly identify putative therapeutic targets.

Citation Format: Quentin Bailleul, Mélanie Arcicasa, Audrey Hochart, Andria Rakotomalala, Marie Castets, Eddy Pasquier, Pierre-Olivier Angrand, Eric Adriaenssens, Xuefen Le Bourhis, Pierre Leblond, Samuel Meignan. Impact of H3.3K27M mutation on diffuse intrinsic pontine glioma's resistance to treatment [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 5005.

Enhancement of Breast Cancer Cell Aggressiveness by lncRNA H19 and its Mir-675 Derivative: Insight into Shared and Different Actions

Breast cancer is a major public health problem and the leading world cause of women death by cancer. Both the recurrence and mortality of breast cancer are mainly caused by the formation of metastasis. The long non-coding RNA H19, the precursor of miR-675, is involved in breast cancer development. The aim of this work was to determine the implication but, also, the relative contribution of H19 and miR-675 to the enhancement of breast cancer metastatic potential. We showed that both H19 and miR-675 increase the invasive capacities of breast cancer cells in xenografted transgenic zebrafish models. In vitro, H19 and miR-675 enhance the cell migration and invasion, as well as colony formation. H19 seems to induce the epithelial-to-mesenchymal transition (EMT), with a decreased expression of epithelial markers and an increased expression of mesenchymal markers. Interestingly, miR-675 simultaneously increases the expression of both epithelial and mesenchymal markers, suggesting the induction of a hybrid phenotype or mesenchymal-to-epithelial transition (MET). Finally, we demonstrated for the first time that miR-675, like its precursor H19, increases the stemness properties of breast cancer cells. Altogether, our data suggest that H19 and miR-675 could enhance the aggressiveness of breast cancer cells through both common and different mechanisms.

Development of a human in vitro blood-brain tumor barrier model of diffuse intrinsic pontine glioma to better understand the chemoresistance

Background

Pediatric diffuse intrinsic pontine glioma (DIPG) represents one of the most devastating and lethal brain tumors in children with a median survival of 12 months. The high mortality rate can be explained by the ineligibility of patients to surgical resection due to the diffuse growth pattern and midline localization of the tumor. While the therapeutic strategies are unfortunately palliative, the blood–brain barrier (BBB) is suspected to be responsible for the treatment inefficiency. Located at the brain capillary endothelial cells (ECs), the BBB has specific properties to tightly control and restrict the access of molecules to the brain parenchyma including chemotherapeutic compounds. However, these BBB specific properties can be modified in a pathological environment, thus modulating brain exposure to therapeutic drugs. Hence, this study aimed at developing a syngeneic human blood–brain tumor barrier model to understand how the presence of DIPG impacts the structure and function of brain capillary ECs.

Methods

A human syngeneic in vitro BBB model consisting of a triple culture of human (ECs) (differentiated from CD34⁺-stem cells), pericytes and astrocytes was developed. Once validated in terms of BBB phenotype, this model was adapted to develop a blood–brain tumor barrier (BBTB) model specific to pediatric DIPG by replacing the astrocytes by DIPG-007, -013 and -014 cells. The physical and metabolic properties of the BBTB ECs were analyzed and compared to the BBB ECs. The permeability of both models to chemotherapeutic compounds was evaluated.

Results

In line with clinical observation, the integrity of the BBTB ECs remained intact until 7 days of incubation. Both transcriptional expression and activity of efflux transporters were not strongly modified by the presence of DIPG. The permeability of ECs to the chemotherapeutic drugs temozolomide and panobinostat was not affected by the DIPG environment.

Conclusions

This original human BBTB model allows a better understanding of the influence of DIPG on the BBTB ECs phenotype. Our data reveal that the chemoresistance described for DIPG does not come from the development of a “super BBB”. These results, validated by the absence of modification of drug transport through the BBTB ECs, point out the importance of understanding the implication of the different protagonists in the pathology to have a chance to significantly improve treatment efficiency.

Transcriptomic Analysis of Breast Cancer Stem Cells and Development of a pALDH1A1:mNeptune Reporter System for Live Tracking

Many solid cancers are hierarchically organized with a small number of cancer stem cells (CSCs) able to regrow a tumor, while their progeny lacks this feature. Breast CSC is known to contribute to therapy resistance. The study of those cells is usually based on their cell-surface markers like CD44^high /CD24^low/neg or their aldehyde dehydrogenase (ALDH) activity. However, these markers cannot be used to track the dynamics of CSC. Here, a transcriptomic analysis is performed to identify segregating gene expression in CSCs and non-CSCs, sorted by Aldefluor assay. It is observed that among ALDH-associated genes, only ALDH1A1 isoform is increased in CSCs. A CSC reporter system is then developed by using a far red-fluorescent protein (mNeptune) under the control of ALDH1A1 promoter. mNeptune-positive cells exhibit higher sphere-forming capacity, tumor formation, and increased resistance to anticancer therapies. These results indicate that the reporter identifies cells with stemness characteristics. Moreover, live tracking of cells in a microfluidic system reveals a higher extravasation potential of CSCs. Live tracking of non-CSCs under irradiation treatment show, for the first time, live reprogramming of non-CSCs into CSCs. Therefore, the reporter will allow for cell tracking to better understand the implication of CSCs in breast cancer development and recurrence.

Enzymatically Activated Glyco-Prodrugs of Doxorubicin Synthesized by a Catalysis-Free Diels-Alder Reaction

The severe side effects associated with the use of anthracycline anticancer agents continues to limit their use. Herein we describe the synthesis and preliminary biological evaluation of three enzymatically activatable doxorubicin-oligosaccharide prodrugs. The synthetic protocol allows late stage variation of the carbohydrate and is compatible with the use of disaccharides such as lactose as well as more complex oligosaccharides such as xyloglucan oligomers. The enzymatic release of doxorubicin from the prodrugs by both protease (plasmin) and human carboxylesterases (hCE1 and 2) was demonstrated in vitro and the cytotoxic effect of the prodrugs was assayed on MCF-7 breast cancer cells.

Developing a MEMS Device with Built-in Microfluidics for Biophysical Single Cell Characterization

This study combines the high-throughput capabilities of microfluidics with the sensitive measurements of microelectromechanical systems (MEMS) technology to perform biophysical characterization of circulating cells for diagnostic purposes. The proposed device includes a built-in microchannel that is probed by two opposing tips performing compression and sensing separately. Mechanical displacement of the compressing tip (up to a maximum of 14 µm) and the sensing tip (with a quality factor of 8.9) are provided by two separate comb-drive actuators, and sensing is performed with a capacitive displacement sensor. The device is designed and developed for simultaneous electrical and mechanical measurements. As the device is capable of exchanging the liquid inside the channel, different solutions were tested consecutively. The performance of the device was evaluated by introducing varying concentrations of glucose (from 0.55 mM (0.1%) to 55.5 mM (10%)) and NaCl (from 0.1 mM to 10 mM) solutions in the microchannel and by monitoring changes in the mechanical and electrical properties. Moreover, we demonstrated biological sample handling by capturing single cancer cells. These results show three important capabilities of the proposed device: mechanical measurements, electrical measurements, and biological sample handling. Combined in one device, these features allow for high-throughput multi-parameter characterization of single cells.

Abstract 2881: CXCL1 and CCL5, induced by ionizing radiation, reprogram nontumorigenic cancer cells into cancer stem cells in breast cancer

Identification of cancer stem cells (CSC) in solid tumors - with self-renewal, multipotency, tumorigenesis, and therapy resistance capacities - has opened path to new targeting therapeutic approaches. However, CSC targeting alone might not be sufficient to eradicate a tumor. Indeed, recent studies showed that cancer cells are plastic, and conventional therapies, such as radiotherapy, can lead to cancer cells (non-CSC) reprogramming into iCSC (induced-CSC). The goal of our work is to identify the molecular mechanisms responsible for treatment-induced CSC emergence. First, we have shown that conditioned media from irradiated non-CSC is sufficient to induce iCSC reprogramming. These results suggest that cell plasticity might be actively regulated by diffusible factors secreted by irradiated cells. By using proteins arrays and ELISA, we demonstrated that the secretion of a specific cocktail of chemokines is induced by ionizing radiation, such as CXCL1 and CCL5. Interestingly, recombinant CXCL1 and CCL5 treatments increase the sphere forming capacity (SFC) of isolated non-CSC treated population. Concomitantly, treatment with neutralizing antibodies targeting CXCL1 and CCL5 leads to a decreased CSC number (ALDH+ cells). We also studied the expression of the corresponding chemokines receptors, by flow cytometry. First, we saw that reprogrammable ALDH- cells are enriched for CXCL1 and CCL5 receptors expressing cells compare to unsorted population or ALDH+ population (CSC). We analysed the reprogramming potential of isolated ALDH-/receptor-positive cells versus ALDH-/receptor-negative cells. The ALDH-/receptor-positive-derived cell population is more able to form spheres and overcomes the receptor-negative-derived population when the two populations are mixed and tested for their sphere forming capacity. The use of pharmacological inhibitors against the receptors induce a slight decrease of CSC. Taken together, our results indicate the involvement of chemokines, in particular CXCL1 and CCL5, in the reprogramming mechanism. To validate the implication of CXCL1 and CCL5 and in a pre-clinical perspective, we are currently beginning an in vivo experiment to study the effects of CXCL1 and CCL5 inhibition on tumor development and on CSC enrichment in vivo.

Citation Format: Justine Bailleul-Dubois, Nadège Bidan, Raphaëlle Mouttet-Audouard, Mélanie Arcicasa, Karine Hannebicque, Yuki Takayama, Samuel Meignan, Xuefen Le Bourhis, Chann Lagadec. CXCL1 and CCL5, induced by ionizing radiation, reprogram nontumorigenic cancer cells into cancer stem cells 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 2881. doi:10.1158/1538-7445.AM2017-2881

[MET receptor inhibition: Hope against resistance to targeted therapies?]

Overcoming the drug resistance remains a crucial issue in cancer treatment. For refractory patients, the use of MET receptor tyrosine kinase inhibitors seems to be hopeful. Indeed, important mechanisms underlying drug resistance argue for association of MET inhibitors with targeted therapies, both on first-line to prevent a primary resistance and on the second line to overcoming acquired resistance. Indeed, met gene amplification is the second most common alteration involved in acquired resistance to anti-epidermal growth factor receptor (EGFR) therapies in non-small cells lung cancer (NSCLC). Hypoxia, for its part, can activate MET transcription and amplifies HGF signaling resulting in MET activation, which could be involved in vascular endothelial growth factor (VEGF) inhibitors escape. In HER2 positive breast cancers, MET amplification may also induce tumor cells a hatch escape, resulting in secondary resistance. Finally, some patients with BRAF mutated melanoma exhibit primary resistance to BRAF inhibition by stromal HGF (ligand of MET) secretion resulting in MET receptor activation. Experimental data highlight the role of MET in primary and secondary resistance and encourage combined treatments including MET inhibitors. In this context, several promising clinical trials are in progress in numerous cancers (NSCLC, melanoma, breast cancer, glioblastoma…) using combination of anti-MET and other specific therapies targeting EGFR, BRAF, VEGF or HER2. This review summarizes the potential benefits that MET inhibition should provide to patients with cancer refractory to targeted therapies.

Human epidermal growth factor receptor 3 in head and neck squamous cell carcinomas

Human epidermal growth factor receptor 3 (HER3) is a member of the human epidermal growth factor receptor (HER) family. The main characteristic of HER3 is that it does not possess tyrosine kinase activity, unlike other HERs. The role of HER3 in tumorigenesis has now been recognized, particularly in head and neck squamous cell carcinomas (HNSCCs). Despite conflicting studies, HER3 was found to be overexpressed in HNSCC samples, and correlates with disease progression and poor survival, especially when it is coexpressed with other HERs. HER3 is a significant factor in HNSCC treatment resistance. Indeed, HER3 is a major mechanism described for cetuximab resistance because of modification of epidermal growth factor receptor (EGFR) internalization and by phosphotidylinositol-3-kinase (PI3K)/AKT signaling pathway activation. HER3 also affects resistance to tyrosine kinase inhibitors (TKIs) and thereby promotes treatment escape and radiotherapy resistance by activation of the survival signaling pathway. To counteract this, pharmacologic inhibitors of HER3 are currently in development and could significantly improve HNSCC treatment. © 2016 Wiley Periodicals, Inc. Head Neck 38: E2412-E2418, 2016.

F14512, a polyamine-vectorized inhibitor of topoisomerase II, exhibits a marked anti-tumor activity in ovarian cancer

Epithelial ovarian cancer is the fourth cause of death among cancer-bearing women and frequently associated with carboplatin resistance, underlining the need for more efficient and targeted therapies. F14512 is an epipodophylotoxin-core linked to a spermine chain which enters cells via the polyamine transport system (PTS). Here, we investigate this novel concept of vectorization in ovarian cancer. We compared the effects of etoposide and F14512 on a panel of five carboplatin-sensitive or resistant ovarian cancer models. We assessed the incorporation of F17073, a spermine-linked fluorescent probe, in these cells and in 18 clinical samples. We then showed that F14512 exhibits a high anti-proliferative and pro-apoptotic activity, particularly in cells with high levels of F17073 incorporation. Consistently, F14512 significantly inhibited tumor growth compared to etoposide, in a cisplatin-resistant A2780R subcutaneous model, at a dose of 1.25 mg/kg. In addition, ex vivo analysis indicated that 15 out of 18 patients presented a higher F17073 incorporation into tumor cells compared to normal cells. Overall, our data suggest that F14512, a targeted drug with a potent anti-tumor efficacy, constitutes a potential new therapy for highly PTS-positive and platinum-resistant ovarian cancer-bearing patients.

Nerve growth factor and proNGF simultaneously promote symmetric self-renewal, quiescence, and epithelial to mesenchymal transition to enlarge the breast cancer stem cell compartment

The discovery of cancer stem cells (CSCs) fundamentally advanced our understanding of the mechanisms governing breast cancer development. However, the stimuli that control breast CSC self-renewal and differentiation have still not been fully detailed. We previously showed that nerve growth factor (NGF) and its precursor proNGF can stimulate breast cancer cell growth and invasion in an autocrine manner. In this study, we investigated the effects of NGF and proNGF on the breast CSC compartment and found that NGF or proNGF enrich for CSCs in several breast cancer cell lines. This enrichment appeared to be achieved by increasing the number of symmetric divisions of quiescent/slow-proliferating CSCs. Interestingly, in vitro NGF pretreatment of MCF-7 luminal breast cancer cells promoted epithelial to mesenchymal transition in tumors of severe combined immunodeficient mice. Furthermore, p75(NTR), the common receptor for both neurotrophins and proneurotrophins, mediated breast CSC self-renewal by regulating the expression of pluripotency transcription factors. Our data indicate, for the first time, that the NGF/proNGF/p75(NTR) axis plays a critical role in regulating breast CSC self-renewal and plasticity.

Abstract 2428: Translational study of F14512, a novel vectorised epipodophyllotoxin, which demonstrates a marked activity on ovarian cancer models from patients

Epithelial ovarian cancer is the fourth cause of death among cancer-bearing women, frequently associated with carboplatin resistance, underlining the need of more efficient and targeted therapies. F14512 is a novel concept of drug vectorization that we propose here to investigate in ovarian cancer models. F14512 is an epipodophyllotoxin-core linked to a spermine chain, which enters selectively tumor cells via the polyamine transport system (PTS), currently in clinical phase II evaluation in AML. We compared the effects of F14512 versus etoposide against OVCAR-3, IGROV-1, SKOV-3, A2780S and A2780R cancer cell lines. Using the F17073 PTS fluorescent probe, we determined the PTS activity of these cells and of 18 clinical samples. As results, F14512 displayed strong anti-proliferative and pro-apoptotic activities in carboplatin-resistant models, being increased in cell lines with high levels of PTS. Consistently, at a dose of 1.25 mg/kg, F14512 significantly inhibited tumor growth in cisplatin-resistant SKOV-3 xenograft model. Interestingly, ex vivo analysis indicated that 15 patients sample out of 18 presented a higher F17073 fluorescent probe incorporation into CD326-positive tumor cells as compared to normal cells, even in the case of 2 platinum-refractory patients. Therefore, F14512 is a targeted drug with a potent anti-tumor efficacy regardless the status of cisplatin resistance. The high PTS activity detected in fresh clinical samples highlights the potential of F14512 as a new therapy for PTS-positive and platinum resistant ovarian cancer patients.

Citation Format: Benoît Thibault, Gregoire Zorza, Samuel Meignan, Nicolas Guilbaud, Christian Bailly, Jean-Pierre Delord, Bettina Couderc, Anna Kruczynski, Pierre Ferre, Jean-Philippe Annereau. Translational study of F14512, a novel vectorised epipodophyllotoxin, which demonstrates a marked activity on ovarian cancer models from patients. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2428. doi:10.1158/1538-7445.AM2015-2428

Anticancer activity of koningic acid and semisynthetic derivatives

A screening program aimed at discovering novel anticancer agents based on natural products led to the selection of koningic acid (KA), known as a potent inhibitor of glycolysis. A method was set up to produce this fungal sesquiterpene lactone in large quantities by fermentation, thus allowing (i) an extensive analysis of its anticancer potential in vitro and in vivo and (ii) the semi-synthesis of analogues to delineate structure-activity relationships. KA was characterized as a potent, but non-selective cytotoxic agent, active under both normoxic and hypoxic conditions and inactive in the A549 lung cancer xenograft model. According to our SAR, the acidic group could be replaced to keep bioactivity but an intact epoxide is essential.

Long survival in a child with a mutated K27M-H3.3 pilocytic astrocytoma

We report the first case of a child with a H3F3A K27M mutated pilocytic astrocytoma, who presented with a 10 years survival, and underwent spontaneous malignant transformation. The complex tumoral chromosomal rearrangements were consistent for genomic instability and for the histopathological features of malignant transformation into glioblastoma. H3F3A K27M mutations are rarely observed in benign neoplasms and may be associated with an adverse outcome. This mutation might not be the major driver that led to the onset of tumorigenesis, and we could consider that the associated TP53 mutation, would be required for malignant transformation.

Activity of the polyamine-vectorized anti-cancer drug F14512 against pediatric glioma and neuroblastoma cell lines

The poor prognosis of children with high-grade glioma (HGG) and high-risk neuroblastoma, despite multidisciplinary therapeutic approaches, demands new treatments for these indications. F14512 is a topoisomerase II inhibitor containing a spermine moiety that facilitates selective uptake by tumor cells via the Polyamine Transport System (PTS) and increases topoisomerase II poisoning. Here, F14512 was evaluated in pediatric HGG and neuroblastoma cell lines. PTS activity and specificity were evaluated using a fluorescent spermine-coupled probe. The cytotoxicity of F14512, alone or in combination with ionizing radiation and chemotherapeutic agents, was investigated in vitro. The antitumor activity of F14512 was assessed in vivo using a liver-metastatic model of neuroblastoma. An active PTS was evidenced in all tested cell lines, providing a specific and rapid transfer of spermine-coupled compounds into cell nuclei. Competition experiments confirmed the essential role of PTS in the cell uptake and cytotoxicity of F14512. This cytotoxicity appeared greater in neuroblastoma cells compared with HGG cells but appeared independent of PTS activity levels. In vivo evaluation confirmed a marked and prolonged antitumoral effect in neuroblastoma cells. The combinations of F14512 with cisplatin and carboplatin were often found to be synergistic, and we demonstrated the significant radiosensitizing potential of F14512 in the MYCN-amplified Kelly cell line. Thus, F14512 appears more effective than etoposide in pediatric tumor cell lines, with greater efficacy in neuroblastoma cells compared with HGG cells. The synergistic effects observed with platinum compounds and the radiosensitizing effect could lead to a clinical development of the drug in pediatric oncology.

New selective carbonic anhydrase IX inhibitors: synthesis and pharmacological evaluation of diarylpyrazole-benzenesulfonamides

Carbonic anhydrase (CA) IX expression is increased upon hypoxia and has been proposed as a therapeutic target since it has been associated with poor prognosis, tumor progression and pH regulation. We report the synthesis and the pharmacological evaluation of a new class of human carbonic anhydrase (hCA) inhibitors, 4-(5-aryl-2-hydroxymethyl-pyrazol-1-yl)-benzenesulfonamides. A molecular modeling study was conducted in order to simulate the binding mode of this new family of enzyme inhibitors within the active site of hCA IX. Pharmacological studies revealed high hCA IX inhibitory potency in the parameters nanomolar range. This study showed that the position of sulfonamide group in meta of the 1-phenylpyrazole increase a selectivity hCA IX versus hCA II of our compounds. An in vitro antiproliferative screening has been performed on the breast cancer MDA-MB-231 cell using doxorubicin as cytotoxic agent and in presence of selected CA IX inhibitor. The results shown that the cytotoxic efficiency of doxorubicin in an hypoxic environment, expressed in IC50 value, is restored at 20% level with 1μM CA IX inhibitor.

Abstract 3799: Polyamine Transport System (PTS) activity and hijacking in cancer cells: New option in Head and Neck tumors treatment with the polyamine-containing drug candidate F14512

The Polyamine Transport System, although not clearly identified at the molecular level in eukaryotic organisms, was found over activated in many types of cancer cells, such as leukemia, prostate, melanoma and NSCLC. Polyamines are implicated in many biological functions, and the need for polyamines in tumor cells, conveyed by the PTS, is crucial. New therapeutic strategies consist to use this transport system to deliver a cytotoxic agent specifically into cancer cells. Head and neck cancer remains the 6th common cancer with a very poor survival rate indicating the crucial need for new targeted strategies. For this study, we used 4 Head and Neck (H & N) cancer cell lines representative of various localizations: CAL 33 and CAL 27 from base of the tongue, Fadu from the pharynx and SQ20B from the larynx. Here, using a polyamine-coupled fluorescent probe, we show that the PTS is active in all head and neck cancer cell lines regardless the tumor localization. In these models, flow cytometry demonstrated that the PTS incorporates quickly, massively and specifically the probe into cancer cells. Confocal microscopy observations revealed that the spermine probe accumulates into the cell nuclei, the site of action of F14512 which is a potent topoisomerase II inhibitor. Considering this property, we evaluated the potential of the F14512 (Pierre Fabre laboratories, France) in these H & N cancer cell lines. F14512 contains a PTS-recognized spermine side chain attached to an epipodophyllotoxin moiety targeting topoisomerase II. We found that F14512 presents a much higher cytotoxicity than etoposide in the 4 cell lines. Competition assays showed that this effect is dependent of the PTS activity and confirmed the targeted action of F14512 against cells with active PTS. The high efficiency of F14512 in the head and neck cancer cell lines is reported here for the first time and may be of interest for the future development of this novel drug candidate, currently in phase 1 clinical trial in leukemia. Studies are in progress, using fresh tumor biopsies from patients with head and neck cancer, to analyze the PTS status of the tumors using the specific spermine-containing fluorescent probe and to evaluate the activity of F14512.

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 3799. doi:1538-7445.AM2012-3799

Abstract 3266: Cilengitide targets more efficiently pediatric than adult glioma cells in vitro through cell detachment and anoikis induction

Despite the development of numerous clinical trials in pediatric cancers, the prognosis for children with high grade gliomas (HGG) remains poor, indicating a critical need for new treatments. Cilengitide (EMD 121974, Merck KgaA, Germany), a new compound in early phase clinical trial, is a selective antagonist of αvβ3 and αvβ5 integrins, known to be involved in tumor growth, angiogenesis and metastasis development. A previous hopeful study shown that Cilengitide is able to control the growth of tumor from adult glioblastoma U87MG xenografts through blood vessel growth inhibition [1]. The aim of our study was to evaluate, the direct efficiency of Cilengitide on pediatric glioma cell lines and to determine its mechanism of action in these specific glioma cells.

For this study, we used a wide tumor cell panel including three high grade (SF188, KNS42, UW479) and two low grade (Res259, Res186) pediatric glioma cell lines compared to the prototypic adult HGG cell line U87MG. Flow cytometry analysis revealed various αVβ3 expression levels but no correlation with the tumor grade. As expected, the pediatric cell line UW479, which doesn't express αVβ3, presents no sensitivity to Cilengitide. All other pediatric cell lines, expressing αVβ3, are sensitive to Cilengitide. Interestingly, U87MG adult cells, which express a high αVβ3 protein level, are very slightly altered by Cilengitide. Thus we have demonstrated a higher cytotoxicity of Cilengitide in pediatric than in adult glioma cells. In addition, the presence of the target appears necessary but not sufficient for Cilengitide action. Cilengitide is a selective antagonist of integrins implicated in cell adhesion. Cell detachment assay have shown a rapid and dose dependant Cilengitide action in pediatric cell lines expressing αVβ3 as well as in adult cells which detach from their matrix after only 2h of treatment. However, this detachment is translated in a Cilengitide cytotoxicity in pediatric cell lines but not in adult cells that are able to growth in spite of the strong cell detachment induced by Cilengitide. Interestingly, growth kinetics in non adherent conditions, revealed that pediatric glioma cells were sensitive to anoikis and so died after Cilengitide-induced cell detachment. In contrast, adult glioma cells are able to form cells clusters and to resist to anoikis and thus to Cilengitide-induced detachment.

In conclusion, Cilengitide action on glioma cells appears dependent of αVβ3 expression and sensitivity to anoikis, two properties found in the majority of pediatric cell lines. Thus Cilengitide is able to target directly and efficiently pediatric glioma cells in vitro. Future in vivo experiments should confirm these promising results in pediatric glioma orthotopic xenografts models.

[1] Yamada et al., Effect of the angiogenesis inhibitor Cilengitide (EMD 121974) on glioblastoma growth in nude mice.

Neurosurgery, 2006.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3266. doi:10.1158/1538-7445.AM2011-3266

Brain-derived neurotrophic factor and neurotrophin-4/5 are expressed in breast cancer and can be targeted to inhibit tumor cell survival

PURPOSE

Given that nerve growth factor has previously been shown to be involved in breast cancer progression, we have tested here the hypothesis that the other neurotrophins (NT) are expressed and have an influence in breast tumor growth.

EXPERIMENTAL DESIGN

The expression of brain-derived neurotrophic factor (BDNF), NT-3 and NT-4/5, as well as the neurotrophin receptor p75(NTR), TrkB, and TrkC, was studied by RT-PCR, Western blotting, and immunohistochemistry in cell lines and tumor biopsies. The biological impacts of neurotrophins, and associated mechanisms, were analyzed in cell cultures and xenografted mice.

RESULTS

BDNF and NT-4/5 were expressed and secreted by breast cancer cells, and the use of blocking antibodies suggested an autocrine loop mediating cell resistance to apoptosis. The corresponding tyrosine kinase receptor TrkB was only rarely observed at full length, whereas the expression of TrkB-T1, lacking the kinase domain, as well as p75(NTR), were detected in all tested breast cancer cell lines and tumor biopsies. In contrast, NT-3 and TrkC were not detected. SiRNA against p75(NTR) and TrkB-T1 abolished the antiapoptotic effect of BDNF and NT-4/5, whereas the pharmacological inhibitors K252a and PD98059 had no effect, suggesting the involvement of p75(NTR) and TrkB-T1, but not kinase activities from Trks and MAPK. In xenografted mice, anti-BDNF, anti-NT-4/5, anti-p75(NTR), or anti-TrkB-T1 treatments resulted in tumor growth inhibition, characterized by an increase in cell apoptosis, but with no change in proliferation.

CONCLUSION

BDNF and NT-4/5 contribute to breast cancer cell survival and can serve as prospective targets in attempts to inhibit tumor growth.

Overexpression of p75(NTR) increases survival of breast cancer cells through p21(waf1)

The p75 neurotrophin receptor (p75(NTR)) plays a critical role in various neuronal and non-neuronal cell types by regulating cell survival, differentiation and proliferation. To evaluate the influence of p75(NTR) in breast cancer development, we have established and characterized breast cancer cells which stably overexpress p75(NTR). We showed that p75(NTR) overexpression per se promoted cell survival to apoptogens with a concomitant slowdown of cell growth. The pro-survival effect is associated with an increased expression of the inhibitor of apoptosis protein-1 (c-IAP1), a decrease of TRAIL-induced cleavage of PARP, procaspase 9 and procaspase 3, and a decrease of cytochrome C release from the mitochondria. The anti-proliferative effect is due to a cell accumulation in G0/G1, associated with a decrease of Rb phosphorylation and an increase of p21(waf1). Interestingly, inhibition of p21(waf1) with siRNA not only restores proliferation but also abolishes the pro-survival effect of p75(NTR), indicating the key role of p21(waf1) in the biological functions of p75(NTR). Finally, using a SCID mice xenograft model, we showed that p75(NTR) overexpression favors tumor growth and strongly increases tumor resistance to anti-tumoral treatment. Together, our findings suggest that p75(NTR) overexpression in breast tumor cells could favor tumor survival and contribute to tumor resistance to drugs. This provides a rationale to consider p75(NTR) as a potential target for the future design of innovative therapeutic strategies.

Ku86 is important for TrkA overexpression-induced breast cancer cell invasion

PURPOSE

We have recently shown that breast tumors express high levels of TrkA compared with normal breast tissues, with TrkA overexpression enhancing breast cancer cell invasion in vitro and metastasis in animal models. In this study, we tried to identify molecules involved in TrkA overexpression-mediated biological effects in breast cancer cells.

EXPERIMENTAL DESIGN

We used a proteomic-based approach to identify proteins involved in TrkA overexpression-stimulated invasion of MDA-MB-231 breast cancer cells. Proteins from control and TrkA overexpressing cells were separated using a cup-loading two-dimensional electrophoresis system before MALDI and LC-MS/MS mass spectrometry analysis.

RESULTS

Among several putative regulated proteins, Ku86 was found increased in TrkA overexpressing cells. Moreover, Ku86 was co-immunoprecipitated with TrkA, suggesting the interaction of these two proteins in TrkA overexpressing cells. Interestingly, inhibition with small-interfering RNA and neutralizing antibodies showed that Ku86 was required for TrkA-stimulated cell invasion.

CONCLUSIONS AND CLINICAL RELEVANCE

These data allowed the identification of Ku86 as a new player involved in metastasis in breast cancer cells. Our findings suggest that TrkA and its down stream signaling pathways should be regarded as potential new targets for the development of future breast cancer therapy.

TrkA Overexpression Enhances Growth and Metastasis of Breast Cancer Cells, and Ku86 Is Crucial for TrkA Overexpression-Induced Breast Cancer Cell Invasion

The Trk family of neurotrophin tyrosine kinase receptors is emerging as an important player in carcinogenic progression in non-neuronal tissues. Here, we show that breast tumors present high levels of TrkA and phospho-TrkA compared to normal breast tissues. To further evaluate the precise functions of TrkA overexpression in breast cancer development, we have performed a series of biological tests using breast cancer cells that stably overexpress TrkA. We show that (1) TrkA overexpression promoted cell growth, migration and invasion in vitro; (2) overexpression of TrkA per se conferred constitutive activation of its tyrosine kinase activity; (3) signal pathways including PI3K-Akt and ERK/p38 MAP kinases were activated by TrkA overexpression and were required for the maintenance of a more aggressive cellular phenotype; and (4) TrkA overexpression enhanced tumor growth, angiogenesis and metastasis of xenografted breast cancer cells in immunodeficient mice. Moreover, recovered metastatic cells from the lungs exhibited enhanced anoikis resistance that was abolished by the pharmacological inhibitor K252a, suggesting that TrkA-promoted breast tumor metastasis could be mediated at least in part by enhancing anoikis resistance. Together, these results provide the first direct evidence that TrkA overexpression enhances the tumorigenic properties of breast cancer cells and point to TrkA as a potential target in breast cancer therapy.In a second step, we used a proteomic-based approach to identify proteins involved in TrkA overexpression-stimulated invasion of MDA-MB-231 breast cancer cells. Proteins from control and TrkA overexpressing cells were separated using a cup-loading two-dimensional electrophoresis system before MALDI and LC-MS/MS mass spectrometry analysis. Among several putative modified proteins, Ku86 was found to be the major protein which was increased in TrkA overexpressing cells. Moreover, Ku86 was co-immunoprecipitated with TrkA and its level at the cell surface was increased in TrkA overexpressing cells. Interestingly, inhibition with small-interfering RNA and neutralizing antibodies showed that Ku86 was required for TrkA-stimulated cell invasion. Together, these data allowed the identification of Ku86 as a new player involved in metastasis of breast cancer cells.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4169.

TrkA overexpression enhances growth and metastasis of breast cancer cells

The Trk family of neurotrophin tyrosine kinase receptors is emerging as an important player in carcinogenic progression in non-neuronal tissues. Here, we show that breast tumors present high levels of TrkA and phospho-TrkA compared to normal breast tissues. To further evaluate the precise functions of TrkA overexpression in breast cancer development, we have performed a series of biological tests using breast cancer cells that stably overexpress TrkA. We show that (1) TrkA overexpression promoted cell growth, migration and invasion in vitro; (2) overexpression of TrkA per se conferred constitutive activation of its tyrosine kinase activity; (3) signal pathways including PI3K-Akt and ERK/p38 MAP kinases were activated by TrkA overexpression and were required for the maintenance of a more aggressive cellular phenotype; and (4) TrkA overexpression enhanced tumor growth, angiogenesis and metastasis of xenografted breast cancer cells in immunodeficient mice. Moreover, recovered metastatic cells from the lungs exhibited enhanced anoikis resistance that was abolished by the pharmacological inhibitor K252a, suggesting that TrkA-promoted breast tumor metastasis could be mediated at least in part by enhancing anoikis resistance. Together, these results provide the first direct evidence that TrkA overexpression enhances the tumorigenic properties of breast cancer cells and point to TrkA as a potential target in breast cancer therapy.

[Secondary hyperparathyroidism and articular chondrocalcinosis in the aged]

The incidence of articular chondrocalcinosis (ACC) in elderly patients hospitalised in geriatric departments is approximately 30%. Routine studies including a 2 hour calcium/phosphorus balance, parathormone assay and radiological investigations enabled the selection of 73 patients with secondary hyperparathyroidism. ACC was present in 38 of these individuals (52%). They were slightly older (87 +/- 5) than cases of secondary hyperparathyroidism without radiological ACC (84 +/- 8). Among patients with secondary hyperparathyroidism with ACC, there were 90% women and 10% men, while the sex ratio in the department was 77% women and 23% men. Results of calcium/phosphorus balance and parathormone levels were similar, in the presence or absence of ACC.

Pharmacokinetics of nalbuphine in infants, young healthy volunteers, and elderly patients

Nalbuphine is a new agonist and antagonist opioid analgesic agent that undergoes an important hepatic metabolism. In this study, we compared the pharmacokinetics of intravenous and oral nalbuphine in three groups of subjects: group I consisted of 14 children from 1 1/2 to 5 years of age (group IA) and from 5 through 8 1/2 years of age (group IB), group II consisted of 9 healthy male volunteers from 23 to 32 years of age, and group III consisted of 9 elderly patients from 65 to 90 years of age. All subjects and patients had normal hepatic and renal functions. The children received an intravenous injection of nalbuphine (0.2 mg/kg), and the subjects and patients in groups II and III received, at random, 10 mg intravenous injections and 30 mg oral doses of nalbuphine on two separate occasions. The distribution of nalbuphine was not modified with age. Elimination half-life (t1/2) was significantly shorter in group I (0.9 hour) than it was in group II (1.9 hours) and in group III (2.3 hours). Systemic clearance of nalbuphine decreased significantly with age. Absolute bioavailability of nalbuphine increased from F = 12% in group II to 46.3% in group III (p less than 0.01). These findings suggest that doses and rates of administration of nalbuphine should be adapted in younger patients and in elderly patients.

[Serotype 5 pneumococcus in epidemiology and vaccine]

The Streptococcus pneumoniae serotype 5 is commonly isolated in human pathology. In France, it is the fourth pneumococcal serotype for acute pneumonia (9.1%) and bacteremia (6.9%). It appears to be more frequently encountered in Africa: in Dakar, this serotype is the third pneumococcal agent and is one of the more often isolated in meningitis; moreover, its is the third serotype isolated in Nigeria. In the intention of its incorporation in the yet available 14-valent pneumococcal vaccine, we have compared serological response and tolerance among four groups of adults: 1) the first group (23 persons) was only immunized by serotype 5 pneumococcal polysaccharide (50 micrograms); 2) the second group (23 persons) by the 15-valent pneumococcal vaccine (14-valent + serotype 5); 3) the third and the fourth groups (21 and 97 persons) were immunized by the 14-valent pneumococcal vaccine. By comparing the multiplying factors of geometrical means of antibodies levels measured by RIA, it appears that the pneumococcal polysaccharide serotype 5 is immunogenic, dispensed alone (first group) or associated with 14-valent pneumococcal vaccine (second group). No reciprocal interference can be detected between this polysaccharide and the other 14 polysaccharides. The tolerance of the serotype 5 polysaccharide is as good as that of these 14 antigens.

[Comparison of treatment with griseofulvin, beta blockers and calcitonin in 55 cases of post-traumatic algoneurodystrophies]

A comparative study of three treatments of reflex sympathetic dystrophy (selected at random) was carried out on 55 cases : 20 patients were treated with calcitonin, 19 with beta-blocking agents, and 16 with griseofulvin. The delay in drug effect seems similar for the 3 drugs but griseofulvin is associated with a greater failure rate. The beta-blocking agents and calcitonin gave comparable results. beta-Blocking agents appear to obtain better results than other 2 treatments in patients with a psychological component to their disease.

[Polyradiculoneuritis associated with plasmocytoma. Recovery following radiotherapy (author's transl)]

A new case of extensive subacute polyradiculoneuritis associated with a costal plasmocytoma secreting IgG lambda is reported. Radiotherapy of the rib, resulted in remarkable neurological improvement and haematological cure, which have now persisted for more than 5 years, though treatment was discontinued 3 years ago. By its distinctive haematological features, this case illustrates the lack of clear-cut distinction between "solitary" plasmocytoma and multiple myeloma. It also emphasizes the need for systematic testing for plasma cell proliferation when confronted with a subacute or chronic neuropathy of obscure origin.

[The cardiovascular manifestations of Paget's disease]

After reviewing the old ideas (peripheral syndrome and cardiac insufficiency at high outputs) and more recent ideas (arterial and intracardiac vascular calcification), the authors report their experiences based on the study of the histories of 150 patients suffering from Paget's disease followed for several years. First they emphasize the frequent latency of cardiac manifestations looked for systematically by means of the electrocardiogram particularly during evolutive stages of the disease. Electrocardiographic disturbances were observed 91 times and included 43 cases of conduction disorders and 48 of repolarization disorders; their distribution was studied as a function of various inherent parameters, of the patient (age and sex) and of the disease (its evolutive character and its degree of diffusion). On the basis of the anti-arythmic power of calcitonin found during experiments and obtained excellent results three times. Finally the place of cardiovascular manifestations in the pathogenic hypotheses and nosology of Paget's disease is discussed.