Abstract P4-07-16: B-IMMUNE final analysis: a phase Ib/II study of durvalumab combined with dose-dense EC in a neoadjuvant setting for patients with locally advanced luminal B HER2(-) or triple negative breast cancers

Background: Neoadjuvant association of immune checkpoints inhibitors (ICI) and dose dense chemotherapy is promising for triple negative breast cancers (TNBC). However, response rates vary from one study to another. Timing, best chemotherapy partner and efficacy in less immunogenic breast cancer (BC), like luminal B tumors, should be further investigated. This study evaluates for TNBC and luminal B HER2(-) BC the neoadjuvant treatment with paclitaxel followed by a short combination of an anti-PD-L1 antibody with anthracyclines. Method B-IMMUNE (NCT03356860), a multicentric phase Ib/II prospective trial, included patients with stage I to III luminal B HER2(-) or TNBC treated with paclitaxel 80mg/m2 weekly from week 1 to 12 followed by 4 cycles of epirubicine 90mg/m2 and cyclophosphamide 600 mg/m2 (EC) Q2W in a neoadjuvant setting. Phase Ib evaluated a single infusion of durvalumab (anti-PD-L1) combined with the 3rd cycle of EC. Phase II evaluated infusions of durvalumab with the 1st and 3rd EC cycles. Surgery was planned 3 weeks after the last EC cycle. Primary objectives were safety and pathological complete response (pCR) rate compared to a historical control. Secondary endpoint was the overall response rate (ORR) based on breast MRI. Eleven patients were enrolled in a control arm without durvalumab, exclusively for translational research purposes. Based on a 2-stage Simon design with an α = 0.1 and β = 0.1, 22 TNBC patients were needed in the phase II to test a null hypothesis of 30% pCR rate against a one-side alternative of 60%, and 24 luminal B BC patients to test a null hypothesis of 15% pCR rate against a one-side alternative of 40% (including an additional accrual margin of 10% for eventual dropouts). At least 9 pCRs had to be observed among the first 20 evaluable TNBC patients and 6 among the first 22 evaluable luminal B patients to rule out the null hypothesis. Results This analysis concerns the 50 patients treated with the experimental treatment, 3 from the phase Ib and 47 from the phase II part. Median age was 51 y-old (31 to 72y), tumor subtypes were 24 TNBC, 25 Luminal B and one sarcoma excluded from the efficacy analysis. Seven (14%) patients had a stage I tumor, 17 (34%) a stage IIA, 13 (26%) a stage IIB, 8 (16%) a stage IIIA, 4 (8%) a stage IIIB and 1 (2%) a stage IIIC. Concerning safety, 232 AEs were reported on 39/50 patients and 34 (14,6%) were graded ≥ 3. The 5 most frequent all-grade AEs were fatigue (8,2%), diarrhea (5,6%), neutropenia (5,2%), anemia and nausea (4,3%). Most frequent grade 3 AEs were anemia and neutropenia (14,7%). Among 4 immune-related adverse events, all were thyroid disorders. One patient died 10 months after the end of treatment due to progressive disease in the liver. Forty-six of the 47 phase II patients were evaluable for efficacy. pCR was reported in 12/22 TNBC patients (55%) and 8/24 luminal B HER2(-) patients (33%). Subgroup analyses based on PD-L1 expression and TILs score are planned. Conclusions The B-IMMUNE study met its primary objective showing a significant improvement in pCR versus the historical control in both TNBC and in Luminal B HER2(-) BC cohorts with the addition of only 2 doses of durvalumab to the anthracyclines. The safety profile is comparable to those previously described with reported immune related adverse events limited to thyroid endocrine disorders.

Citation Format: Alix Devaux, Gabriela Beniuga, Claire Quaghebeur, Stéphanie Henry, Mieke Van Bockstal, Christine Galant, Paul Delrée, Jean-Luc Canon, Brigitte Honhon, Dominique Korman, Vincent Verschaeve, Christophe Lonchay, Sarah Lefevre, Lionel D’Hondt, Martine Berlière, Sophie Delmarcelle, Jean-Michel Mine, Timour Willems, Gebhard Müller, Nathalie Myant, Isabelle Bar, Sandy Haussy, Pierre G. Coulie, François P. Duhoux, Javier Carrasco. B-IMMUNE final analysis: a phase Ib/II study of durvalumab combined with dose-dense EC in a neoadjuvant setting for patients with locally advanced luminal B HER2(-) or triple negative breast cancers. [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-07-16.

Abstract P2-14-12: B-immune interim analysis: A phase Ib/II study of durvalumab combined with dose-dense EC in a neoadjuvant setting for patients with locally advanced luminal B HER2(-) or triple negative breast cancers

Background: The association of immune checkpoints inhibitors (ICI) and dose dense chemotherapy is a promising combination in a neoadjuvant setting for triple negative breast cancers (TNBC). However, response rates vary from one study to another and timing, best chemotherapy partner and efficacy in breast cancer subtypes considered as less immunogenic, like luminal B tumors, should be further investigated. The B-immune study evaluates a neoadjuvant treatment with paclitaxel followed by a short combination of an anti-PD-L1 antibody with anthracyclines for TNBC and luminal B breast cancers (BC). Method: B-immune (NCT03356860), a multicentric phase Ib/II prospective trial, includes patients with stage I to III luminal B or TNBC treated with paclitaxel 80mg/m2 weekly from week 1 to 12 followed by 4 cycles of epirubicine 90mg/m2 and cyclophosphamide 600 mg/m2 (EC) Q2W in a neoadjuvant setting. The phase Ib evaluated a single infusion of durvalumab (anti-PD-L1) combined with the 3rd cycle of EC. The phase II, in progress, evaluates 2 infusions of durvalumab with the 1st and 3rd cycle of EC respectively. Surgery is planned 3 weeks after the last preoperative treatment. Primary objectives are safety and efficacy based on pathological complete response (pCR) rate. Considering a 2-stage Simon design, 22 TNBC patients are needed in the phase II to detect a pCR rate increase from 30% to 60% and 24 luminal B BC patients are needed to detect a pCR rate increase from 15% to 40% (α = 0.1 and β = 0.1). At least 3 pCRs must be observed among 8 TNBC patients and 2 among 10 Luminal B patients treated in the 1st stage to move to the 2nd stage. Results: This analysis concerns 3 treated patients from phase Ib and 18 from phase II who received the experimental treatment (median age 55 y-old, 10 TNBC, 11 Luminal B, 14% stage I, 67% stage II, 19% stage III). Overall, 169 AEs were reported and 22 (13%) were graded > 2 on 10/21 patients, including 27% of neutropenia (6/22), 22% of anemia (5/22), 13% of severe asthenia (3/22) and 9% of diarrhea (2/22). Four patients (19%) developed thyroid immune endocrine disorders. Efficacy was evaluated on 18 patients included in the 1st stage of phase II (8 TNBC and 10 luminal B). Five among 8 TNBC patients (62%) and 2 among 10 luminal B patients (20%) had a pCR. Conclusions: The B-immune interim analysis reveals an acceptable global safety profile. Reported immune related adverse events were limited to thyroid endocrine disorders. Observed pCR rate after neoadjuvant paclitaxel followed by 2 durvalumab infusions combined to EC chemotherapy warrants pursuing the trial for the TNBC and luminal B cohorts.

Citation Format: Javier Carrasco, Claire Quaghebeur, Stephanie Henry, Christine Galant, Mieke Van Bockstal, Paul Delrée, Brigitte Honhon, Dominique Korman, Vincent Verschaeve, Christophe Lonchay, Sarah Levefre, Lionel D'hondt, Martine Berliere, Sophie Delmarcelle, Jean-Michel Mine, Timour Willems, Gebhard Müller, Nathalie Myant, Isabelle Bar, Manuel Constant, Sandy Haussy, Alix Devaux, Pierre Coulie, Jean-Luc Canon, François Duhoux. B-immune interim analysis: A phase Ib/II study of durvalumab combined with dose-dense EC in a neoadjuvant setting for patients with locally advanced luminal B HER2(-) or triple negative breast cancers [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 P2-14-12.

[2021 update of the GEFPICS' recommendations for HER2 status assessment in invasive breast cancer in France]

The last international guidelines on HER2 determination in breast cancer have been updated in 2018 by the American Society of Clinical Oncology and College of American Pathologists, on the basis of a twenty-year practice and results of numerous clinical trials. Moreover, the emerging HER2-low concept for 1+ and 2+ non amplified breast cancers lead to refine French practices for HER2 status assessment. The GEFPICS group, composed of expert pathologists, herein presents the latest French recommendations for HER2 status evaluation in breast cancer, taking into account the ASCO/CAP guidelines and introducing the HER2-low concept. In the era of personalized medicine, HER2 status assessment remains one of the most important biomarkers in breast cancer and its quality guaranties the optimal patients' care. French pathologists' commitment in theranostic biomarker quality is more than ever required to provide the most efficient cares in oncology.

Tumor sequencing is useful to refine the analysis of germline variants in unexplained high-risk breast cancer families

Background

Multigene panels are routinely used to assess for predisposing germline mutations in families at high breast cancer risk. The number of variants of unknown significance thereby identified increases with the number of sequenced genes. We aimed to determine whether tumor sequencing can help refine the analysis of germline variants based on second somatic genetic events in the same gene.

Methods

Whole-exome sequencing (WES) was performed on whole blood DNA from 70 unrelated breast cancer patients referred for genetic testing and without a BRCA1, BRCA2, TP53, or CHEK2 mutation. Rare variants were retained in a list of 735 genes. WES was performed on matched tumor DNA to identify somatic second hits (copy number alterations (CNAs) or mutations) in the same genes. Distinct methods (among which immunohistochemistry, mutational signatures, homologous recombination deficiency, and tumor mutation burden analyses) were used to further study the role of the variants in tumor development, as appropriate.

Results

Sixty-eight patients (97%) carried at least one germline variant (4.7 ± 2.0 variants per patient). Of the 329 variants, 55 (17%) presented a second hit in paired tumor tissue. Of these, 53 were CNAs, resulting in tumor enrichment (28 variants) or depletion (25 variants) of the germline variant. Eleven patients received variant disclosure, with clinical measures for five of them. Seven variants in breast cancer-predisposing genes were considered not implicated in oncogenesis. One patient presented significant tumor enrichment of a germline variant in the oncogene ERBB2, in vitro expression of which caused downstream signaling pathway activation.

Conclusion

Tumor sequencing is a powerful approach to refine variant interpretation in cancer-predisposing genes in high-risk breast cancer patients. In this series, the strategy provided clinically relevant information for 11 out of 70 patients (16%), adapted to the considered gene and the familial clinical phenotype.

MiR-210 Is Overexpressed in Tumor-infiltrating Plasma Cells in Triple-negative Breast Cancer

Triple-negative breast cancer (TNBC) is a heterogeneous group of breast cancer and is characterized by aggressiveness and poor prognosis. MicroRNA represents a new class of biomarkers, and accumulating evidence indicates that microRNAs contribute to tumorigenesis and cancer metastasis. It has been described that miR-210 is highly expressed in TNBC, and its overexpression had been linked to poor prognosis. In a previous work, we showed that in TNBC miR-210 is expressed in tumor cells and also in the tumor microenvironment (TME), particularly in inflammatory CD45-LCA positive cells. However, the exact identity of these cells remained unknown. In this study, we performed in situ hybridization and immunohistochemistry using validated antibodies for the different specific immune cell markers on adjacent sections of 23 TNBC infiltrated with immune cells. We found that miR-210 expressing cells in the TME were stained positive with CD79a, a B-cell lineage marker. These tumor-infiltrating cells were negative for CD20 and Ki-67 but positive for MUM1 and CD38 and also expressed immunoglobulins, indicating that they are immunoglobulin-producing plasma cells (PCs). To the best of our knowledge, this is the first study demonstrating miR-210 expression in tumor-infiltrating PCs.

Chromothripsis in an Early Recurrent Chordoid Meningioma

BACKGROUND

Chromothripsis is characterized by a multitude of chromosomal rearrangements during a unique cataclysmic event in a cell life. Disintegration of one or several chromosomes is followed by a chaotic rearrangement of generated fragments. It might play a role in oncogenesis and tumor progression. It is observed in 2%-3% of cancers and is rarely reported in benign tumors. We report a case of massive chromothripsis in a fast growing chordoid meningioma.

CASE DESCRIPTION

A 55-year-old woman was admitted for a meningeal mass developing in the right parietal parasagittal area. She underwent subtotal resection of the tumor. Histologic analysis revealed a chordoid meningioma (World Health Organization grade II). Six months later, magnetic resonance imaging showed a large bilateral tumor recurrence. After a second surgery, the patient received radiotherapy. Thereafter, the clinical course was uneventful. Comparative genomic hybridization showed only a monosomy X in the primary tumor. In the recurrent meningioma, this anomaly was associated with a massive chromothripsis including more than 370 chromosomal abnormalities affecting chromosomes 1-22.

CONCLUSIONS

Chromothripsis is rarely described in benign tumors and especially in meningiomas. In the presented case, the high number of chromosomal rearrangements and the onset of this phenomenon at a later stage of tumor progression are very unusual. The role of surgical stress on the emergence of chromothripsis and its relation with tumor aggressiveness are discussed.

Abstract P4-15-02: TILs variations, proliferative response and PEPI scores in patients with luminal breast cancer receiving neoadjuvant letrozole-palbociclib or chemotherapy: An extended analysis of the NEOPAL trial

Background

The role of chemotherapy in early luminal breast cancer remains challenged. The NEOPAL trial (NCT 02400567; Cottu et al, ESMO 2017 LBA09) compared sequential chemotherapy (CT) and letrozole-palbociclib (LP) as neoadjuvant treatment in PAM50 defined high-risk luminal breast cancer patients, showing that LP might be as efficient as CT with regard to breast conserving surgery and pathological response. We report here extended exploratory pathological results, focusing on tumor infiltrating lymphocytes (TILs), proliferative response and preoperative endocrine prognostic index (PEPI) scores.

Material and Methods

Tumor blocks from baseline biopsy and surgical specimens were available for centralized review from the 106 randomized patients (53 in each arm). TILs quantification, KI67 staining and counting, and ER quantification were performed according to standard methods. Residual proliferative cancer burden (RPCB) and PEPI scores were computed according to published algorithms. Wilcoxon rank sum test and Mann Whitney test were used to compare paired and unpaired data. The chi-square and Fisher exact tests were used for categorical variables.

Results

Overall, median TILs count did not differ between LP and CT patients, both at baseline (p=0.37) and at the end of treatment (p=0.42). Median TILs count climbed from 5% (0-60) to 10% (1-60) in the LP arm (p=0.0026) and from 2% (0-30) to 10% (0-60) in the CT arm (p=0.0023). Median Ki67 dropped sharply in both arms, from 30% (1-80) to 1% (0-30) in the LP arm (p=1.10e-8) and from 30% (2-80) to 5% (0-30) in the CT arm (p=3.10e-9). Decrease in the Ki67 geometric mean was as sharp. Of note, while baseline Ki67 was similar in both arms (p=0.315), decrease in the LP arm was significantly more profound than in the CT arm (p=0.00075). Pathological response according to RPCB were as follows, in the LP and CT arm, respectively: class 0: 9.6%/10.2%; class I: 84.6%/73.5%; class II: 5.8%/16.3%. The relapse free survival PEPI scores were as follow in the LP and CT arm, respectively: class I: 13.5%/16.3%; class II: 59.6%/46.9%; class III: 28.9%/36.8% (p=0.504). Breast cancer specific survival PEPI scores were as follow in the LP and CT arm, respectively: class I: 18.9%/8.2%; class II: 54.7%/40.8%; class III: 26.4%/51%. These results were significantly better in the LP arm (p=0.027). There was no correlation between final TILs quantification and the RPCB or PEPI scores.

Conclusions

In this prospective multicenter study with centralized pathological review, neoadjuvant letrozole-palbociclib combination generates impressive proliferative and endocrine specific response features. It compared well with chemotherapy. The LP combination also significantly increased lymphocytic infiltration. Its clinical significance and utility remain to be elucidated, but it potentially adds new prognostic and theranostic information.

Citation Format: Vincent-Salomon A, Mathieu M-C, Bataillon G, Arnould L, Verrièle V, Ghnassia J-P, Haudebourg J, Penault-Llorca F, Lefebvre C, Maran-Gonzalez A, Guinebretière J-M, Duprez R, Berghian A, Blanc-Fournier C, Calès V, Galant C, Delrée P, Lemonnier J, Delaloge S, Cottu PH. TILs variations, proliferative response and PEPI scores in patients with luminal breast cancer receiving neoadjuvant letrozole-palbociclib or chemotherapy: An extended analysis of the NEOPAL trial [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-15-02.

Myeloperoxidase promotes tube formation, triggers ERK1/2 and Akt pathways and is expressed endogenously in endothelial cells

Myeloperoxidase is a member of the mammalian peroxidase family, mainly expressed in the myeloblastic cell lineage. It is considered a major bactericidal agent as it is released in the phagosome where it catalyzes the formation of reactive oxygen species. It is also released in the extracellular spaces including blood where it is absorbed on (lipo)proteins and endothelial cell surface, interfering with endothelial function. We performed RNA sequencing on MPO-treated endothelial cells, analyzed their transcriptome and validated the profile of gene expression by individual qRT-PCR. Some of the induced genes could be grouped in several functional networks, including tubulogenesis, angiogenesis, and blood vessel morphogenesis and development as well as signal transduction pathways associated to these mechanisms. MPO treatment mimicked the effects of VEGF on several signal transduction pathways, such as Akt, ERK or FAK involved in angiogenesis. Accordingly MPO, independently of its enzymatic activity, stimulated tube formation by endothelial cells. RNA interference also pointed at a role of endogenous MPO in tubulogenesis and endothelium wound repair in vitro. These data suggest that MPO, whether from endogenous or exogenous sources, could play a role in angiogenesis and vascular repair in vivo.

Analysis of T-cell repertoires in early-stage breast carcinomas to evaluate tumor immunogenicity

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Background: Breast carcinomas (BC) are often considered to be weakly immunogenic and thus poorly sensitive to immunotherapy. Methods: We analyzed the repertoire of tumor-infiltrating T cells (TILs) in 41 early BC by sequencing their T cell receptor β genes (TCRβ). Libraries were built using a digital sequencing approach, barcoding each sequenced molecule to improve accuracy and quantification. T cell repertoires were also obtained from paired blood samples allowing identification of T cell clones enriched in the tumors as compared to blood. For 5 patients, CD8+ TILs were cloned ex-vivo from a tumor sample and screened for recognition of autologous predicted neoepitopes. Results: T cell infiltration differed from one tumor to another. Its amount varied of more than 30 fold and its diversity ranged from < 100 to > 5000 different clonotypes. In 34% of the tumors, there was an important T cell infiltration and we detected several clonotypes with a ≥500 fold enrichment as compared to blood. In 22% of the tumors, an important T cell infiltration was observed but without significantly enriched clonotypes. In 43% of the tumors the T cell infiltration was very limited. For 5 tumors with a high T cell infiltration, we screened ex-vivo isolated CD8+ T cell clones for recognition of predicted neoepitopes. In 4 of these tumors, with no enriched clonotypes, no recognition was observed. In 1 of these tumors, with enriched clonotypes, 6 different CD8+ T cell clones recognized 4 predicted neoepitopes. Three of these clones were > 100 fold more frequent in the tumor as compared to blood. Conclusions: About 30% of early BC were infiltrated by T cell clonotypes significantly enriched relative to blood. In one of these tumors some of the most enriched clonotypes recognized neoepitopes, demonstrating that some primary BC are spontaneously immunogenic. About 20% of the tumors had an important T cell infiltration without enriched clonotypes. None of the TIL clones isolated from 4 such tumors recognized predicted neoepitopes. Our results suggest that the detection of intratumorally enriched T cell clonotypes could identify immunogenic tumors, which may be sensitive to treatment with immunostimulatory antibodies.

The MicroRNA miR-210 Is Expressed by Cancer Cells but Also by the Tumor Microenvironment in Triple-Negative Breast Cancer

The triple-negative breast cancer (TNBC) subtype occurs in about 15% of breast cancer and is an aggressive subtype of breast cancer with poor outcome. Furthermore, treatment of patients with TNBC is more challenging due to the heterogeneity of the disease and the absence of well-defined molecular targets. Microribonucleic acid (RNA) represents a new class of biomarkers that are frequently dysregulated in cancer. It has been described that the microRNA miR-210 is highly expressed in TNBC, and its overexpression had been linked to poor prognosis. TNBC are often infiltrated by immune cells that play a key role in cancer progression. The techniques traditionally used to analyze miR-210 expression such as next generation sequencing or quantitative real-time polymerase chain reaction (PCR) do not allow the precise identification of the cellular subtype expressing the microRNA. In this study, we have analyzed miR-210 expression by in situ hybridization in TNBC. The miR-210 signal was detected in tumor cells, but also in the tumor microenvironment, in a region positive for the pan-leucocyte marker CD45-LCA. Taken together, our results demonstrate that miR-210 is expressed in tumor cells but also in the tumor microenvironment. Our results also highlight the utility of using complementary approaches to take into account the cellular context of microRNA expression.

The metabolic waste ammonium regulates mTORC2 and mTORC1 signaling

Two structurally and functionally distinct mammalian TOR complexes control cell growth and metabolism in physiological and pathological contexts including cancer. Upregulated glutaminolysis is part of the metabolic reprogramming occurring in cancer, providing fuels for growth but also liberating ammonium, a potent neurotoxic waste product. Here, we identify ammonium as a novel dose-dependent signal mediating rapid mTORC2 activation and further regulating mTORC1. We show that ammonium induces rapid RICTOR-dependent phosphorylation of AKT-S473, a process requiring the PI3K pathway and further involving the Src-family kinase YES1, the FAK kinase and the ITGβ1 integrin. Release of calcium from the endoplasmic reticulum store triggers rapid mTORC2 activation, similar to ammonium-induced activation, the latter being conversely prevented by calcium chelation.Moreover, in analogy to growth factors, ammonium triggers the AKT-dependent phosphoinhibition of the TSC complex and of PRAS40, two negative regulators of mTORC1. Consistent with mTORC1 stimulation, ammonium induces the inhibitory phosphorylation of 4EBP1, a negative regulator of protein biogenesis. Ammonium however dually impacts on the phosphorylation of p70S6K1 triggering a transient AKT-independent decrease in the phosphorylation of this second mTORC1 readout. Finally, we reveal ammonium as a dose-dependent stimulator of proliferation. This study underscores an mTORC2 and mTORC1 response to the so-called ammonium waste.

Nuclear localization of glutamate-cysteine ligase is associated with proliferation in head and neck squamous cell carcinoma

Glutathione (GSH) is the keystone of the cellular response toward oxidative stress. Elevated GSH content correlates with increased resistance to chemotherapy and radiotherapy of head and neck (HN) tumors. The purpose of the present cross-sectional study was to evaluate whether the expression of glutamate-cysteine ligase (GCL) accounts for the increased GSH availability observed in HN squamous cell carcinoma (SCC). For that purpose, the messenger (m)RNA levels of the modifier (M) and catalytic (C) subunits of GCL and its putative regulators (namely, nuclear factor erythroid 2-related factor 2, heme oxygenase-1 and nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha) were monitored in 35 surgical resections of untreated HNSCC. The localization of GCLM was evaluated using in situ hybridization and immunohistochemistry. GCLM expression was significantly increased in tumor samples, compared with normal mucosa, both at the mRNA and protein level (P=0.029), but the pathway of GCLM activation remains to be elucidated. Protein expression of GCLM was detected in the cytoplasm and nucleus. GCLM and the proliferation marker Ki-67 displayed a similar distribution, being both mainly expressed at the periphery of tumor lobules. The present study reported increased expression of GCL and the rate-limiting enzyme of GSH synthesis, within HNSCC. The nuclear localization of GCLM and the concomitant expression of Ki-67 suggested that the localization of GSH synthesis contributes to the protection against oxidative stress within hotspots of cell proliferation.

Abstract P4-04-10: Early-stage breast carcinomas are infiltrated by oligoclonal T cell populations highly enriched relative to the blood

BACKGROUD: The immunogenicity of some human tumors towards T lymphocytes is well established. Recently, encouraging results have been obtained with immunotherapies inhibiting immune checkpoints in cancers such as melanoma, NSCLC and bladder cancer. Fewer studies explored these treatments in breast cancer (BC) as these tumors are often considered to be poorly immunogenic.

METHODS: We analysed the T cell receptor β-chains variable genes (TCRBV) repertoires of tumor-infiltrating T cells in 17 early BC. We looked for clonally amplified T cells as their presence is an expected consequence of tumor immunogenicity. RNA was extracted and reverse-transcribed from formalin-fixed, paraffin-embedded tumor tissues. A short random sequence was added to the cDNA and used as a unique molecular identifier (UMI) for each cDNA molecule. cDNA encoding TCRBV genes was then amplified and sequenced using high throughput sequencing. Usage of UMIs during this procedure strongly improved the accuracy of the analysis by avoiding amplification biases inherent to the construction of the TCRBV library and by allowing an absolute quantification of TCRBV mRNA molecules normalized with the RPP30 housekeeping gene. TCRBV sequences were aligned using IMGT/HighV-QUEST. The Simpson's index was used to evaluate TCRBV repertoires diversity (ranging from 0 = infinite diversity to 1 = no diversity). For 3 patients, the same procedure was applied on blood T cells collected a few days before tumor resection and the analysis was also carried out on 3 normal tissues obtained from breast reduction surgery.

RESULTS: T cell infiltration varied strongly from one tumor to another ranging from 5 to 2498 TCRBV/103 RPP30 mRNA molecules. TCRBV repertoires analysis indicated that infiltrated T cells corresponded to oligoclonal populations. We observed 3 clonotypes in the smaller repertoire and 74 in the largest one and the Simpson's index ranged from 0.01 to 0.65. Most tumors (16/17) contained at least one clonotype that made up ≥10% of the infiltrating T cells, with the highest observed proportions reaching 80%. Normal breast samples were infiltrated by a more diverse repertoire: 130 to 368 clonotypes were identified in those tissues and Simpson's index ranged from 0.002 to 0.008. Highest observed frequency among those clonotypes was 2%. For 3 BC patients, the frequencies of the most prevalent clonotypes in the tumor were compared to those of the same clonotypes in blood prior to surgery. These T cell clones were 250 to &gt;34000 times more frequent in the tumor than in the blood.

CONCLUSIONS: Some early BC are infiltrated by oligoclonal T cell populations that are highly enriched relative to the blood. Quantitative T cell repertoire analysis allows to distinguish 3 types of BC: (1) tumors without T cell infiltration, (2) tumors with a high T cell infiltration and a small T cell repertoire, and (3) tumors with a high T cell infiltration and a large repertoire. Our observations suggest that anti-tumor T cell responses are ongoing in some early BC and this warrants boosting such responses with immune checkpoint inhibitors in selected patients. T cell repertoire evaluation could be used as a predictive biomarker to identify patients who will benefit from this treatment.

Citation Format: Carrasco J, Schröder D, Coulie PG, Godelaine D, Berlière M, Theate I, Delrée P, Vannuffel P, Galant C, Duhoux FP, Machiels J-P, Canon J-L. Early-stage breast carcinomas are infiltrated by oligoclonal T cell populations highly enriched relative to the blood. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-04-10.

Intestinal immunopathology is associated with decreased CD73-generated adenosine during lethal infection

The ectonucleotidases CD39 and CD73 sequentially degrade the extracellular ATP pool and release immunosuppressive adenosine, thereby regulating inflammatory responses. This control is likely to be critical in the gastrointestinal tract where high levels of ATP are released in particular by commensal bacteria. The aim of this study was therefore to evaluate the involvement of the adenosinergic regulation in the intestine of mice in steady-state conditions and on acute infection with Toxoplasma gondii. We show that both conventional (Tconv) and regulatory (Treg) CD4(+) T lymphocytes express CD39 and CD73 in the intestine of naive mice. CD73 expression was downregulated during acute infection with T. gondii, leading to impaired capacity to produce adenosine. Interestingly, the expression of adenosine receptors was maintained and treatment with receptor agonists limited immunopathology and dysbiosis, suggesting that the activation of adenosine receptors may constitute an efficient approach to control intestinal inflammation associated with decreased ectonucleotidase expression.

Identification by array comparative genomic hybridization of a new amplicon on chromosome 17q highly recurrent in BRCA1 mutated triple negative breast cancer

INTRODUCTION

Triple Negative Breast Cancers (TNBC) represent about 12% to 20% of all breast cancers (BC) and have a worse outcome compared to other BC subtypes. TNBC often show a deficiency in DNA double-strand break repair mechanisms. This is generally related to the inactivation of a repair enzymatic complex involving BRCA1 caused either by genetic mutations, epigenetic modifications or by post-transcriptional regulations. The identification of new molecular biomarkers that would allow the rapid identification of BC presenting a BRCA1 deficiency could be useful to select patients who could benefit from PARP inhibitors, alkylating agents or platinum-based chemotherapy.

METHODS

Genomic DNA from 131 formalin-fixed paraffin-embedded (FFPE) tumors (luminal A and B, HER2+ and triple negative BC) with known BRCA1 mutation status or unscreened for BRCA1 mutation were analysed by array Comparative Genomic Hybridization (array CGH). One highly significant and recurrent gain in the 17q25.3 genomic region was analysed by fluorescent in situ hybridization (FISH). Expression of the genes of the 17q25.3 amplicon was studied using customized Taqman low density arrays and single Taqman assays (Applied Biosystems).

RESULTS

We identified by array CGH and confirmed by FISH a gain in the 17q25.3 genomic region in 90% of the BRCA1 mutated tumors. This chromosomal gain was present in only 28.6% of the BRCA1 non-mutated TNBC, 26.7% of the unscreened TNBC, 13.6% of the luminal B, 19.0% of the HER2+ and 0% of the luminal A breast cancers. The 17q25.3 gain was also detected in 50% of the TNBC with BRCA1 promoter methylation. Interestingly, BRCA1 promoter methylation was never detected in BRCA1 mutated BC. Gene expression analyses of the 17q25.3 sub-region showed a significant over-expression of 17 genes in BRCA1 mutated TNBC (n = 15) as compared to the BRCA1 non mutated TNBC (n = 13).

CONCLUSIONS

In this study, we have identified by array CGH and confirmed by FISH a recurrent gain in 17q25.3 significantly associated to BRCA1 mutated TNBC. Up-regulated genes in the 17q25.3 amplicon might represent potential therapeutic targets and warrant further investigation.

Abstract 392: Helicase-like transcription factor (HLTF) expression and gene methylation in FFPE colon tumors

Background : HLTF, beside its roles in DNA binding, transcriptional and chromatin remodeling, is involved in post-replication DNA repair through its translocase and E3 ubiquitin ligase activities. HLTF is a tumor suppressor, and hypermethylation of its promoter was observed in 30-50% of gastrointestinal cancers. Moreover, HLTF inactivation in Apc-/+ mice induced the transition from colon adenocarcinoma to a carcinoma with high chromosomal instability. The epigenetic heterogeneity of the HLTF promoter could be related to the CpG island methylator phenotype of tumor suppressor genes in colorectal cancers. In the present study we started to investigate HLTF expression in colon cancer progression in relation to the epigenetic status of its gene promoter by using pyrosequencing.

Methods : The HLTF promoter contains a 653 bp CpG island with 59 CpG sites (UCSC) among which 11 CpG sites were selected for this study. Genomic DNA was extracted from (a) HeLa (cervix adenocarcinoma) and RKO (colon carcinoma) cells and (b) from formalin-fixed paraffin-embedded (FFPE) colon tumors. DNA was treated with bisulfite and amplified by PCR the HLTF promoter fragment containing the 11 CpG sites. Pyrosequencing was performed to determine the relative methylation frequency at each site (HLTF PyroMark CpG Assay, Qiagen). HLTF expression was evaluated by immunohistochemistry (IHC) on tissue sections, and by RT-PCR and immunodetection on Western blot for the cell lines.

Results : There was a negative correlation between promoter methylation and HLTF expression at the RNA and protein levels in RKO and HeLa cells. The average methylation rates were 92% for RKO and 25% for HeLa cells which presented HLTF repression and expression, respectively. IHC staining for HLTF was performed in 14 FFPE colon tumors and good pyrosequencing signals was obtained for DNA extracted from 6/14 samples. Three tumor groups were defined, based on the average methylation rate in the HLTF promoter : (a) &lt; 30% ; (b) = 50% ; and (c) &gt; 60%. In groups (a) and (b), the tissue was still well organized and HTLF protein expression was detected by IHC in the glandular epitelium. However, in group (c), the tumors were disorganized and HLTF protein expression was low or undetectable. These preliminary results suggest a correlation between 3 criteria : HLTF immunodetection, tissue organization and low methylation of the HLTF promoter. Two colon tumors did not express HLTF and presented a hypermethylated promoter.

Conclusion : We could optimize pyrosequencing methylation analysis of genomic DNA extracted from 6 FFPE colon tumors, and confirmed that higher HLTF promoter methylation was associated with its repression in correlation with worse tumor phenotypes. This sensitive technique will now be applied to larger number of samples and additional CpG sites will be assessed.

Citation Format: Ludovic Dhont, Alisson Di Stefano, Angela Szucs, Fadi Abdulsater, Isabelle Bar, Paul Delrée, Alexandra Belayew. Helicase-like transcription factor (HLTF) expression and gene methylation in FFPE colon tumors. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 392. doi:10.1158/1538-7445.AM2014-392

Genomic Grade Index (GGI): feasibility in routine practice and impact on treatment decisions in early breast cancer

Purpose

Genomic Grade Index (GGI) is a 97-gene signature that improves histologic grade (HG) classification in invasive breast carcinoma. In this prospective study we sought to evaluate the feasibility of performing GGI in routine clinical practice and its impact on treatment recommendations.

Methods

Patients with pT1pT2 or operable pT3, N0-3 invasive breast carcinoma were recruited from 8 centers in Belgium. Fresh surgical samples were sent at room temperature in the MapQuant Dx™ PathKit for centralized genomic analysis. Genomic profiles were determined using Affymetrix U133 Plus 2.0 and GGI calculated using the MapQuant Dx® protocol, which defines tumors as low or high Genomic Grade (GG-1 and GG-3 respectively).

Results

180 pts were recruited and 155 were eligible. The MapQuant test was performed in 142 cases and GGI was obtained in 78% of cases (n=111). Reasons for failures were 15 samples with <30% of invasive tumor cells (11%), 15 with insufficient RNA quality (10%), and 1 failed hybridization (<1%). For tumors with an available representative sample (≥ 30% inv. tumor cells) (n=127), the success rate was 87.5%. GGI reclassified 69% of the 54 HG2 tumors as GG-1 (54%) or GG-3 (46%). Changes in treatment recommendations occurred mainly in the subset of HG2 tumors reclassified into GG-3, with increased use of chemotherapy in this subset.

Conclusion

The use of GGI is feasible in routine clinical practice and impacts treatment decisions in early-stage breast cancer.

Trial Registration

ClinicalTrials.gov NCT01916837, http://clinicaltrials.gov/ct2/show/NCT01916837

Clinical utility of an epigenetic assay to detect occult prostate cancer in histopathologically negative biopsies: results of the MATLOC study

PURPOSE

Concern about possible false-negative prostate biopsy histopathology findings often leads to rebiopsy. A quantitative methylation specific polymerase chain reaction assay panel, including GSTP1, APC and RASSF1, could increase the sensitivity of detecting cancer over that of pathological review alone, leading to a high negative predictive value and a decrease in unnecessary repeat biopsies.

MATERIALS AND METHODS

The MATLOC study blindly tested archived prostate biopsy needle core tissue samples of 498 subjects from the United Kingdom and Belgium with histopathologically negative prostate biopsies, followed by positive (cases) or negative (controls) repeat biopsy within 30 months. Clinical performance of the epigenetic marker panel, emphasizing negative predictive value, was assessed and cross-validated. Multivariate logistic regression was used to evaluate all risk factors.

RESULTS

The epigenetic assay performed on the first negative biopsies of this retrospective review cohort resulted in a negative predictive value of 90% (95% CI 87-93). In a multivariate model correcting for patient age, prostate specific antigen, digital rectal examination and first biopsy histopathological characteristics the epigenetic assay was a significant independent predictor of patient outcome (OR 3.17, 95% CI 1.81-5.53).

CONCLUSIONS

A multiplex quantitative methylation specific polymerase chain reaction assay determining the methylation status of GSTP1, APC and RASSF1 was strongly associated with repeat biopsy outcome up to 30 months after initial negative biopsy in men with suspicion of prostate cancer. Adding this epigenetic assay could improve the prostate cancer diagnostic process and decrease unnecessary repeat biopsies.

A tissue biopsy-based epigenetic multiplex PCR assay for prostate cancer detection

Background

PSA-directed prostate cancer screening leads to a high rate of false positive identifications and an unnecessary biopsy burden. Epigenetic biomarkers have proven useful, exhibiting frequent and abundant inactivation of tumor suppressor genes through such mechanisms. An epigenetic, multiplex PCR test for prostate cancer diagnosis could provide physicians with better tools to help their patients. Biomarkers like GSTP1, APC and RASSF1 have demonstrated involvement with prostate cancer, with the latter two genes playing prominent roles in the field effect. The epigenetic states of these genes can be used to assess the likelihood of cancer presence or absence.

Results

An initial test cohort of 30 prostate cancer-positive samples and 12 cancer-negative samples was used as basis for the development and optimization of an epigenetic multiplex assay based on the GSTP1, APC and RASSF1 genes, using methylation specific PCR (MSP). The effect of prostate needle core biopsy sample volume and age of formalin-fixed paraffin-embedded (FFPE) samples was evaluated on an independent follow-up cohort of 51 cancer-positive patients. Multiplexing affects copy number calculations in a consistent way per assay. Methylation ratios are therefore altered compared to the respective singleplex assays, but the correlation with patient outcome remains equivalent. In addition, tissue-biopsy samples as small as 20 μm can be used to detect methylation in a reliable manner. The age of FFPE-samples does have a negative impact on DNA quality and quantity.

Conclusions

The developed multiplex assay appears functionally similar to individual singleplex assays, with the benefit of lower tissue requirements, lower cost and decreased signal variation. This assay can be applied to small biopsy specimens, down to 20 microns, widening clinical applicability. Increasing the sample volume can compensate the loss of DNA quality and quantity in older samples.

[Malignant solitary fibrous tumor of the abdominal wall in a man]

We report the first case of malignant solitary fibrous tumor of the abdominal wall in a man. Immunohistochemical staining for CD34 and bcl-2 were positive. Surprisingly, estrogen and progesterone receptors were focally positive. Expression of steroid hormone receptor in solitary fibrous tumor was rarely reported in the literature. In a few series, these receptors were identified as a risk factor of recurrences after surgical excision. Six months after complete surgical resection of the mass, our patient has been quite well without any evidence of recurrence.

[Malignant peripheral nerve sheath tumor in the posterior mediastinum]

We report the case of a 52-year-old male patient who developed a malignant peripheral nerve sheath tumor (MPNST) localized in the posterior mediastinum. The diagnosis of this rare tumor is difficult because the clinical presentation of the benign or malignant types is often similar, i.e. elective pain and bone erosions. Similarly, radiological procedures do not always allow distinction between the two types. MNR and CT-scan are the first line procedures: they localize and characterize the lesions, and CT-scan can also be a guide for biopsies. Histological diagnosis is required, but diagnosis can be compromised by the heterogeneous nature of the tumor. Surgical treatment should be undertaken whenever possible. Survival was unusually long in our patient, more than 5 years after discovery of the MPNST. This type of sarcoma is often very aggressive with frequent development of local recurrences and metastases.

Fibrinolysis and cardiovascular risk factors: association with fibrinogen, lipids, and monocyte count

BACKGROUND

Numerous risk factors for cardiovascular disease (CVD) have been determined by clinical epidemiological observations. The missing link could be related to endothelial dysfunction and the resulting hypofibrinolysis.

METHODS

In this cross-sectional study, we evaluated 160 subjects (134 in primary prevention) characterized by their clinical cardiovascular risk factors (CVRF), i.e., age, gender, diabetes, hypertension, smoking habit, and history of coronary event or stroke, and by their blood parameters, i.e., C-reactive protein (CRP), fibrinogen, leukocyte count (WBC), monocyte count (MC), total cholesterol, HDL cholesterol (HDL-c), LDL cholesterol (LDL-c), and triglycerides. We assessed their fibrinolytic capacity with a new method, Euglobulin Clot Lysis Time (ECLT). The effects of these clinical and biological parameters were evaluated in multivariate analysis (backward stepwise regression).

RESULTS

ECLT was correlated with the Framingham risk score and was significantly influenced by the number of clinical CVRF. MC was confirmed to be an important predictive factor influencing ECLT. In subjects without clinical CVRF (n=46), 67% of the variability of ECLT was explained by a combination of MC, LDL-c, and fibrinogen.

CONCLUSION

ECLT is related to the number of epidemiologically defined clinical CVRF and to MC. Because it integrates many risk factors, we suggest that fibrinolytic function could be a biological test useful for physicians in the cardiovascular risk assessment of their patients.

Monoclonal antibodies against LDL progressively oxidized by myeloperoxidase react with ApoB-100 protein moiety and human atherosclerotic lesions

Oxidized-LDL are involved in atherosclerosis pathogenesis, while the production of anti-ox-LDL monoclonal antibodies is critical for the development of diagnostic tools. This work reports the production of four monoclonal antibodies raised against human LDL, oxidized at different levels by the myeloperoxidase system. Characterization of these monoclonal antibodies showed that they do not cross-react with neither native LDL, VLDL nor hydrogen peroxide or Cu(2+)-oxidized LDL. Three of these antibodies recognize an epitope restricted to the protein moiety of mildly oxidized LDL, whereas the fourth antibody was partly dependent on the lipid presence of strongly oxidized LDL. All the antibodies were shown to react with human atherosclerotic lesions.

[Multiple cholesterol emboli syndrome: beneficial effects of early heparin therapy. A case report]

The multiple cholesterol emboli syndrome (MCES) is a rare, multi-organ disease than can occur spontaneously or after arterial or cardiac catheterization, arteriography, angioplasty, cardiovascular surgery, oral or intravenous anticoagulation, systemic fibrinolysis and cardiorespiratory resuscitation, predominantly in male subjects with disseminated atherosclerosis over the age of 60 years. Clinical signs of MCES vary considerably depending on the organs involved, but the signs most frequently encountered are renal failure, skin lesions (livedo reticularis, purple toc, ulcers, etc) and transient eosinophilia. Optimal treatment of this syndrome is controversial and is often symptomatic. However, the most effective measure remains prevention based on identification of high-risk patients, treatment with platelet antiaggregants and careful handling of catheters. This syndrome has a serious prognosis in the majority of cases. In this article, the authors describe a case of MCES. After thoracic aortography, this 73-years-old patient presented typical clinical sign of MCES (angina, cerebrovascular accident, bilateral blindness, transient renal failure and splenic infarction). The clinical course was favourable in response to heparin therapy and splenectomy and caudal pancreatectomy. Histology confirmed the presence of cholesterol emboli in the lumen of splenic arterioles. Except in the case of severe bleeding diathesis, the authors recommend early heparin therapy for MCES caused by catheterization, angioplasty or cardiovascular surgery. However, complementary studies must be performed to more clearly define the effects of heparin on MCES.

Effects of Schwann cell transplantation in a contusion model of rat spinal cord injury

Cultured Schwann cells were transplanted at various delays into a spinal cord contusion injury performed at low thoracic level in adult female rats. The Schwann cells were purified from the dorsal root ganglia of adult syngeneic animals. the transplants were well tolerated, and the transplanted Schwann cells invaded the injured spinal cord. As quantified using video image analysis, the survival and growth of the transplanted cells were poor when the grafting procedure was performed 3-4 days after injury and very good when performed immediately or 10 days after injury, in which cases post-traumatic micro- and macrocavitation were strongly reduced. In animals grafted immediately after injury but not in animals grafted after 10 days, post-traumatic astrogliosis was much reduced. The Schwann cells transplanted area was invaded by numerous regenerating axons, the vast majority of which were, based on the neurotransmitter (CGRP and SP) profile, originating from dorsal root ganglion. No regeneration of the corticospinal tract as assessed after anterograde tracing or of descending aminergic fibers could be demonstrated.

Image analysis of neuritic regeneration by adult rat dorsal root ganglion neurons in culture: quantification of the neurotoxicity of anticancer agents and of its prevention by nerve growth factor or basic fibroblast growth factor but not brain-derived neurotrophic factor or neurotrophin-3

Peripheral neuropathies are a common side effect of chemotherapeutic agents, particularly antineoplastic drugs such as taxol, cisplatin, or vinca-alkaloids (vincristine, vinblastine, vindesine). Using dissociated cultures of adult rat dorsal root ganglion (DRG) neurons and video image analysis after neurofilament immunostaining, we have designed a system that allows: (i) rapid screening of potential neurotoxic agents, with the establishment of dose-response curves and the calculation of IC50; (ii) quantification of neurotrophic effects; and (iii) demonstration of neuroprotection by trophic factors. In particular, we show that nerve growth factor (NGF) and basic fibroblast growth factor (bFGF) stimulate in vitro neuritic regeneration by adult rat DRG neurons, while brain-derived neurotrophic factor and neurotrophin-3 lack such effects. Furthermore, 24 h of pretreatment by NGF or bFGF drastically decreases the neurotoxic effect of vincristine and cisplatin.

Transforming growth factor beta as a neuronoglial signal during peripheral nervous system response to injury

In contrast to the central nervous system (CNS), the peripheral nervous system (PNS) displays an important regenerative ability which is dependent, at least in part, on Schwann cell properties. The mechanisms which stimulate Schwann cells to adapt their behavior after a lesion to generate adequate conditions for PNS regeneration remain unknown. In this work, we report that adult rat dorsal root ganglion (DRG) neurons are able, after a lesion performed in vivo or when they are dissociated and cultured in vitro, to synthesize transforming growth factor beta (TGF beta), a pleiotropic growth factor implicated in wound healing processes and in carcinogenesis. This TGF beta is tentatively identified as the beta-1 isoform. Adult rat DRG neurons release a biologically active form of TGF beta which is able to elicit multiple Schwann cell responses including a stimulation to proliferate. Moreover, purified TGF beta-1 produces a Schwann cell morphology alteration and decreases the secretion of tissue-type plasminogen activator (tPA) and enhances the secretion of plasminogen activator inhibitor (PAI) by Schwann cells. This generates conditions which are thought to favor a successful neuritic regrowth. Furthermore, purified TGF beta-1 stimulates type IV collagen mRNA expression in Schwann cells. This subtype of collagen is associated with the process of myelinization. Finally, TGF beta-1 decreases nerve growth factor (NGF) mRNA expression by Schwann cells, an effect which could participate in the maintenance of a distoproximal NGF gradient during nerve regeneration. We propose that neuronal TGF beta plays an essential role as a neuronoglial signal that modulates the response of Schwann cells to injury and participates in the successful regeneration processes observed in the PNS.

Plasticity of developing and adult dorsal root ganglion neurons as revealed in vitro

We review recent data on the plasticity of dorsal root ganglion (DRG) neurons as revealed during cultivation in vitro. Some experiments on cultured developing DRG neurons and on adult DRG neurons in vivo are also mentioned. Cultured developing and adult DRG neurons can be switched from an apolar to a multipolar phenotype by fetal calf serum or fibronectin. The effect is concentration dependent and occurs through an early modification of cell-substratum interaction. Adult DRG neurons synthesize and release within hours after injury TGF beta-1, which is a mitogen and a differentiation factor for Schwann cells. Finally, adult DRG neurons express in vitro neurotransmitters that are not expressed in vivo. This neurotransmitter plasticity can be modulated in vitro by some growth factors and in vivo by distal or proximal axotomy.

Experimental acute traumatic injury of the adult rat spinal cord by a subdural inflatable balloon: methodology, behavioral analysis, and histopathology

We describe an experimental model to produce closed traumatic injuries to the spinal cord of adult rats. This model uses an inflatable balloon that is introduced in the dorsal subdural space and moved to a location rostral to the laminectomy site. The spinal cord trauma can be graded by varying either the duration of compression or the volume of saline used to inflate the balloon. The locomotor deficit of animals with various degrees of injury has been assessed at increasing delays after trauma. The parameters generating transient or definitive deficits of varying intensity were defined. Some injured animals underwent nuclear magnetic resonance imaging. Detailed histopathological studies demonstrated that the extent of the spinal lesion was significantly correlated with the physical parameters of compression and with the severity of the behavioral deficit.

Distribution of immunoreactive T-kininogen in rat nervous tissues

The distribution in the nervous system of T-kininogen, the third kallikrein-resistant kininogen of the rat, was determined using bioassays and a radioimmunoassay system. In rat brain homogenates, trypsin released large amounts of a kinin-like myostimulating activity while urinary kallikrein released small amounts. The kinins released by trypsin were identified by HPLC as mostly T-kinin. Radioimmunoassays showed that a T-kininogen-like immunoreactive factor was uniformly distributed throughout the central nervous system. Higher levels were found in female rats than in male rats. Maximum levels were observed in newborn animals. A slight increase of T-kininogen content of the brain was observed after turpentine injection while T-kininogen level in liver was dramatically increased. T-kininogen plasma contamination to the nervous tissues was estimated by injecting 125I-labelled T-kininogen. The T-kininogen content of rat cultured cells and neurons was also examined. Highest levels were found in dorsal root ganglia neurons, lower levels in Schwann cells, phaeochromocytoma cells, mixed cells from spinal ganglion and in astrocytes. Immunocytochemistry showed the presence of T-kininogen in the cytoplasm of cultured dorsal root ganglia neurons and embryonic hippocampal neurons. The distribution of T-kininogen throughout the central and peripheral nervous system of the rat, the variations of its level during the life span suggest that T-kininogen would play the role of a cysteine proteinase inhibitor and not that of a T-kinin-releasing substrate in nervous tissues.

Modulation of proteolytic activity during neuritogenesis in the PC12 nerve cell: differential control of plasminogen activator and plasminogen activator inhibitor activities by nerve growth factor and dibutyryl-cyclic AMP

Extracellular proteolysis is considered to be required during neuritic outgrowth to control the adhesiveness between the growing neurite membrane and extracellular matrix proteins. In this work, PC12 nerve cells were used to study the modulation of proteolytic activity during neuronal differentiation. PC12 cells were found to contain and release a 70-75-kDa tissue-type plasminogen activator (tPA) and a much less abundant 48-kDa urokinase-type plasminogen activator. A plasminogen activator inhibitor (PAI) activity with molecular sizes of 54 and 58 kDa was also detected in PC12 cell conditioned medium and formed high-molecular-mass complexes with released tPA. Release of PAI activity was dependent on treatment with nerve growth factor (NGF), whereas tPA synthesis and release were under control of a cyclic AMP-dependent mechanism and increased on treatment with dibutyryl-cyclic AMP [(But)2cAMP] or cholera toxin. Simultaneous treatment with NGF and (But)2cAMP resulted in increases of both tPA and PAI release and enhancement of tPA-PAI complex formation. The resulting plasminogen activator activity in conditioned medium was high in (But)2cAMP-treated cultures with short neuritic outgrowth but remained low in NGF- or NGF plus (But)2cAMP-treated cultures, where neurite extension was, respectively, large and very large. These results suggest that excess proteolytic activity may be detrimental to neuritic outgrowth and that not only PAI release but also tPA-PAI complex formation is associated with production of large and stable neuritic outgrowth. This can be understood as an involvement of PAI in the protection against neurite-destabilizing proteolytic activity.

Kainate and NMDA toxicity for cultured developing and adult rat spiral ganglion neurons: further evidence for a glutamatergic excitatory neurotransmission at the inner hair cell synapse

In the inner ear, the excitatory amino acid glutamate is a proposed neurotransmitter acting at the synapse between hair cells and afferent auditory neurons. Using cultures of 5-day-old rat auditory neurons, we show that the afferent auditory neuronal population can be divided, on the basis of its sensitivity to the neuronotoxic effect of glutamate and its analogs, in at least 3 subpopulations, one responding to N-methyl-D-aspartate (NMDA), one responding to kainate and a third minor one unresponsive to NMDA, kainic acid and glutamate. No toxic effect of quisqualate is observed. The use of specific antagonists (kynurenate and 2-amino-5-phosphonovalerate (DAP-5) demonstrates the specificity of the receptors to the excitatory amino acids on the afferent auditory neurons. Afferent auditory neurons from adult rats can also be cultured and in these preparations only the large neurons are sensitive to glutamate, kainate and NMDA while the small neurons are not responsive, suggesting that a glutamatergic neurotransmission occurs only at this synapse between the inner hair cells and the large radial afferent auditory neurons. We also show that, in vitro, the organ of Corti releases, in response to an increased potassium concentration and in the presence of calcium, a toxic activity for the afferent auditory neurons that is antagonized by kynurenate and DAP-5. Pathophysiological implications are discussed.

Grafts of syngenic cultured, adult dorsal root ganglion-derived Schwann cells to the injured spinal cord of adult rats: preliminary morphological studies

Highly enriched cultures of Schwann cells were obtained from adult rat dorsal root ganglia and implanted (5 x 10(5) -9 x 10(5) cells) in the spinal cord of syngenic adult rats at the site of an acute compression lesion produced by a subdural inflatable microballoon. These autografts survived and invaded the host tissue, reducing central cavitation and astrocytic gliosis. They dramatically promoted ingrowth of axons, the majority of which appeared to come from the dorsal roots as judged by their neuropeptide content. Invasion of the transplants by descending, e.g. aminergic fibers, was negligible at survival times of up to 4 months. Nonetheless, autologous Schwann cells, which are readily available in the host, represent a promising material for grafts into the injured spinal cord.

An in vivo model of varicella-zoster virus latent infection of dorsal root ganglia

We describe here the first in vivo model of varicella-zoster virus (VZV) latent infection in the adult rat peripheral nervous system. Infected Mewo cells were injected subcutaneously along the spine of healthy adult rats. No clinical sign of infection was observed even 9 months after inoculation. Humoral immune response to VZV was detected in all infected animals throughout the study (9 months). The presence of viral material in dissociated and cultured dorsal root ganglia (DRG) from inoculated animals was studied by immunoperoxidase and in situ hybridization. When DRGs from infected animals were plated in culture from 1 month and up to 9 months after inoculation, viral nucleic acids and proteins were detected in neurons. Furthermore, trypsinization and subcultivation of infected neurons in culture is needed to reactivate infectious virus at least in some of the neurons. This model provides a useful tool for studying 1) the molecular mechanisms leading to an in vivo latency, 2) the role of the immune system, in particular cellular immunity, on the establishment, maintenance, and reactivation of latency, 3) the neurotropism of mutant viruses, and 4) the effects of antiviral agents.

Acute and persistent varicella-zoster virus infection of human and murine neuroblastoma cell lines

Human and murine neuroblastoma cell lines were infected in vitro with varicella-zoster virus (VZV). Infected human neuroblastoma cells (IMR-32) supported the synthesis of abundant viral antigens as detected by indirect immunoperoxidase labeling using human serum rich in anti-VZV antibodies and did not survive the infection. In situ hybridization (ISH) with VZV-cloned probes revealed a strong hybridization signal in these infected cells. During cultivation, the virus was released in the culture medium, and viral polypeptides were revealed by Western blotting of infected cells, using either a monoclonal anti-gpI antibody or a rabbit antiserum. All these findings indicate that IMR-32 cells support a productive and lytic infection by VZV, whether infected by cell-free virus or by cocultivation with infected cells. Murine neuroblastoma cells (neuro-2A) survived VZV infection and did not produce any infectious virus. No VZV-specific proteins were detected in infected cells either by immunolabeling or by Western blotting. However, viral nucleic acids could be detected by ISH, indicating that mouse neuroblastoma cells displayed a nonproductive, nonlytic infection. Infected neuro-2A cells have been examined by ISH using probes corresponding to immediate early (IE) genes 4, 62, and 63 and late (L) gene 31 encoding gpII. A strong hybridization signal was detected when infected cells were probed with a fragment containing the IE genes 62 and 63. Lower levels of hybridization were detected with the other probes, corresponding to IE or L genes. These systems allow comparative molecular analysis of persistent and acute infection of nerve cells by VZV.