Abstract P5-08-07: HER3, MET and immune pathways play important roles in the resistance of triple negative breast cancer (TNBC) after neoadjuvant anti-EGFR (panitumumab) combined with FEC 100

Background: Our group has previously reported (SABCS 2012, abstract 1081) a 2-fold higher pathologic complete response (pCR) rate in TNBC treated with panitumumab+FEC100 (47%) than with the standard therapy alone. However, in a half of the patients (pts) a residual tumor (RT) was detected. Having in mind the detrimental impact of resistant TNBC on patient outcome, we have investigated the tumor tissue factors that might have been important in development of resistance to this treatment.

Methods: 40 TNBC pts, treated with 8 cycles the anti-EGFR antibody panitumumab combined with FEC 100 for the first 4 and with docetaxel only for the last 4 cycles, were eligible. All pts underwent breast surgery after the neoadjuvant chemotherapy (NACT) completion. Formalin-fixed, paraffin-embedded tumor samples were collected before and after NACT for biomarker analysis. EGFR, HER3, IGF-1R, MET and the number of FOXP3+ or CD8+ tumor-infiltrating lymphocytes (TIL) were evaluated by immunohistochemistry (IHC). Expression of the kinases was graded semi-quantitatively (histoscores).

Results: Out of 40 treated pts, 21 demonstrated a RT (53%, according to the Chevallier classification, PMID 8338056). The IHC data were available for 17 pts. Since high EGFR expression was important for pCR achievement in this study (SABC 2012), we first investigated the expressions of EGFR, HER3 and MET in the RT. The results are presented in Table 1.

Table 1post-NACT RTn = 17EGFR down or flatEGFR up143HER3 upHER3 flatHER3 upHER3 flat8512MET upMET down or flatMET upMET down or flatMET upMET down or flatMET upMET down or flat17220120

Overall, among the 9 cases (cs) with increased post-NACT HER3 expression (HER3 up), only 1 had increased MET (MET up), while among the 7 cs with no change in HER3 post-CTNA (HER3 flat), 4 had MET expression increased.

Interestingly, although the pre-NACT IGF-1R expression was a strong predictor of pCR (p = 0.028, SABCS 2012), no significant changes in this kinase expression were observed in the RT, compared to the pre-NACT levels. Most RT had low IGF-1R scores (<100). The only 2 RT in which IGF-1R was increased post-CTNA were small groups of tumor cells either in breast or in the nodes, heavily surrounded by lymphocytes.

The density of TIL post-NACT correlated principally with the% of tumor mass (TM) reduction. Among the 7 pts with average reduction of 20%, there was only 1 cs with a good InSitu Immune Response (ISIR: dense TIL, with CD8+/FOXP3+ > 1.2). On the contrary, among the 9 pts with average TM reduction of 90%, 8 demonstrated a good ISIR.

Conclusion: The results indicate that HER3 and MET play significant roles in development of TNBC resistance to the anti-EGFR agents. Those molecules seem to drive 2 different resistance pathways in TNBC, as it has been shown in other malignancies. As several anti-HER3 or anti-MET drugs are nowadays available, we find very important investigating the expression of HER3 and MET in each TNBC pt pre- and post-NACT, in order to rapidly detect and combat the resistance. The ISIR-stimulating agents may bring an additional therapeutic benefit to those patients.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-08-07.

Altered neuropathic pain behaviour in a rat model of depression is associated with changes in inflammatory gene expression in the amygdala

The association between chronic pain and depression is widely recognized, the comorbidity of which leads to a heavier disease burden, increased disability and poor treatment response. This study examined nociceptive responding to mechanical and thermal stimuli prior to and following L5-L6 spinal nerve ligation (SNL), a model of neuropathic pain, in the olfactory bulbectomized (OB) rat model of depression. Associated changes in the expression of genes encoding for markers of glial activation and cytokines were subsequently examined in the amygdala, a key brain region for the modulation of emotion and pain. The OB rats exhibited mechanical and cold allodynia, but not heat hyperalgesia, when compared with sham-operated counterparts. Spinal nerve ligation induced characteristic mechanical and cold allodynia in the ipsilateral hindpaw of both sham and OB rats. The OB rats exhibited a reduced latency and number of responses to an innocuous cold stimulus following SNL, an effect positively correlated with interleukin (IL)-6 and IL-10 mRNA expression in the amygdala, respectively. Spinal nerve ligation reduced IL-6 and increased IL-10 expression in the amygdala of sham rats. The expression of CD11b (cluster of differentiation molecule 11b) and GFAP (glial fibrillary acidic protein), indicative of microglial and astrocyte activation, and IL-1β in the amygdala was enhanced in OB animals when compared with sham counterparts, an effect not observed following SNL. This study shows that neuropathic pain-related responding to an innocuous cold stimulus is altered in an animal model of depression, effects accompanied by changes in the expression of neuroinflammatory genes in the amygdala.

Alterations in the endocannabinoid system in the rat valproic acid model of autism

The endocannabinoid system plays a crucial role in regulating emotionality and social behaviour, however it is unknown whether this system plays a role in symptoms associated with autism spectrum disorders. The current study evaluated if alterations in the endocannabinoid system accompany behavioural changes in the valproic acid (VPA) rat model of autism. Adolescent rats prenatally exposed to VPA exhibited impaired social investigatory behaviour, hypoalgesia and reduced lococmotor activity on exposure to a novel aversive arena. Levels of the endocananbinoids, anandamide (AEA) and 2-arachidonylglycerol (2-AG) in the hippocampus, frontal cortex or cerebellum were not altered in VPA- versus saline-exposed animals. However, the expression of mRNA for diacylglycerol lipase α, the enzyme primarily responsible for the synthesis of 2-AG, was reduced in the cerebellum of VPA-exposed rats. Furthermore, while the expression of mRNA for the 2-AG-catabolising enzyme monoacylglycerol lipase was reduced, the activity of this enzyme was increased, in the hippocampus of VPA-exposed animals. CB1 or CB2 receptor expression was not altered in any of the regions examined, however VPA-exposed rats exhibited reduced PPARα and GPR55 expression in the frontal cortex and PPARγ and GPR55 expression in the hippocampus, additional receptor targets of the endocannabinoids. Furthermore, tissue levels of the fatty acid amide hydrolase substrates, AEA, oleoylethanolamide and palmitoylethanolamide, were higher in the hippocampus of VPA-exposed rats immediately following social exposure. These data indicate that prenatal VPA exposure is associated with alterations in the brain's endocannabinoid system and support the hypothesis that endocannabinoid dysfunction may underlie behavioural abnormalities observed in autism spectrum disorders.

The endocannabinoid system in the rat dorsolateral periaqueductal grey mediates fear-conditioned analgesia and controls fear expression in the presence of nociceptive tone

BACKGROUND AND PURPOSE

Endocannabinoids in the midbrain periaqueductal grey (PAG) modulate nociception and unconditioned stress-induced analgesia; however, their role in fear-conditioned analgesia (FCA) has not been examined. The present study examined the role of the endocannabinoid system in the dorsolateral (dl) PAG in formalin-evoked nociceptive behaviour, conditioned fear and FCA in rats.

EXPERIMENTAL APPROACH

Rats received intra-dlPAG administration of the CB(1) receptor antagonist/inverse agonist rimonabant, or vehicle, before re-exposure to a context paired 24 h previously with foot shock. Formalin-evoked nociceptive behaviour and fear-related behaviours (freezing and 22 kHz ultrasonic vocalization) were assessed. In a separate cohort, levels of endocannabinoids [2-arachidonoyl glycerol (2-AG) and N-arachidonoyl ethanolamide (anandamide; AEA)] and the related N-acylethanolamines (NAEs) [N-palmitoyl ethanolamide (PEA) and N-oleoyl ethanolamide (OEA)] were measured in dlPAG tissue following re-exposure to conditioned context in the presence or absence of formalin-evoked nociceptive tone.

KEY RESULTS

Re-exposure of rats to the context previously associated with foot shock resulted in FCA. Intra-dlPAG administration of rimonabant significantly attenuated FCA and fear-related behaviours expressed in the presence of nociceptive tone. Conditioned fear without formalin-evoked nociceptive tone was associated with increased levels of 2-AG, AEA, PEA and OEA in the dlPAG. FCA was specifically associated with an increase in AEA levels in the dlPAG.

CONCLUSIONS AND IMPLICATIONS

Conditioned fear to context mobilises endocannabinoids and NAEs in the dlPAG. These data support a role for endocannabinoids in the dlPAG in mediating the potent suppression of pain responding which occurs during exposure to conditioned aversive contexts.

LINKED ARTICLES

This article is part of a themed section on Cannabinoids in Biology and Medicine. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2012.165.issue-8. To view Part I of Cannabinoids in Biology and Medicine visit http://dx.doi.org/10.1111/bph.2011.163.issue-7.

Altered microRNA expression profile in human pituitary GH adenomas: down-regulation of miRNA targeting HMGA1, HMGA2, and E2F1

CONTEXT

MicroRNA (miRNA) are an important class of regulators of gene expression. Altered miRNA expression has been constantly found in human neoplasias and plays an important role in the process of carcinogenesis.

OBJECTIVE

The aim of this study was to identify specific miRNA whose expression is altered in GH-secreting pituitary adenomas.

DESIGN

Using a miRNACHIP microarray, we have analyzed the miRNA expression profile of human GH adenomas vs. normal pituitary gland.

RESULTS

We report the identification of a set of miRNA, including miR-34b, miR-326, miR-432, miR-548c-3p, miR-570, and miR-603, drastically and constantly down-regulated in GH adenomas. We demonstrate that these miRNA target genes such as high-mobility group A1 (HMGA1), HMGA2, and E2F1, whose overexpression and/or activation plays a critical role in pituitary tumorigenesis. We also show that the enforced expression of the down-regulated miRNA has a negative role on the growth regulation of pituitary adenoma cells. Finally, an inverse correlation is found between the expression of these miRNA and HMGA1 and HMGA2 protein levels in GH adenomas.

CONCLUSION

Our study identifies a specific subset of miRNA, whose down-regulation might contribute to pituitary tumorigenesis.

A population-based study of prostate cancer chemotherapy

The use of chemotherapy in the treatment of prostate cancer is a relatively recent development, with no published data on the patterns of care in the UK. We carried out a population-based study to assess variation in the use of prostate cancer chemotherapy over time in a UK cancer network.

Mumps outbreaks in four universities in the North West of England: prevention, detection and response

Evidence suggests that primary and secondary vaccine failure have contributed to recent university-based mumps outbreaks. We describe the epidemiology and public health management of two such outbreaks that occurred simultaneously in two areas of the North West of England, affecting four universities, using data from routine surveillance, serology testing, and telephone interviews and electronic questionnaires. Vaccination status was obtained from GP records. Cases were predominantly first year students living in university halls of residence. Public health response involved active surveillance, isolation advice and targeted vaccination clinics. Many students lack natural immunity and mumps vaccination. Factors hindering the public health response include delayed notifications, inability to readily define the 'at risk' population, low vaccine uptake, and lack of an evidence-based, cost effective strategy.

Integrated genomic profiling identifies loss of chromosome 11p impacting transcriptomic activity in aggressive pituitary PRL tumors

Integrative genomics approaches associating DNA structure and transcriptomic analysis should allow the identification of cascades of events relating to tumor aggressiveness. While different genome alterations have been identified in pituitary tumors, none have ever been correlated with the aggressiveness. This study focused on one subtype of pituitary tumor, the prolactin (PRL) pituitary tumors, to identify molecular events associated with the aggressive and malignant phenotypes. We combined a comparative genomic hybridization and transcriptomic analysis of 13 PRL tumors classified as nonaggressive or aggressive. Allelic loss within the p arm region of chromosome 11 was detected in five of the aggressive tumors. Allelic loss in the 11q arm was observed in three of these five tumors, all three of which were considered as malignant based on the occurrence of metastases. Comparison of genomic and transcriptomic data showed that allelic loss impacted upon the expression of genes located in the imbalanced region. Data filtering allowed us to highlight five deregulated genes (DGKZ, CD44, TSG101, GTF2H1, HTATIP2), within the missing 11p region, potentially responsible for triggering the aggressive and malignant phenotypes of PRL tumors. Our combined genomic and transcriptomic analysis underlines the importance of chromosome allelic loss in determining the aggressiveness and malignancy of tumors.

[Sentinel node procedure in head and neck cutaneous melanoma]

INTRODUCTION

Sentinel lymph node (SLN) biopsy is frequently discussed in the management of cutaneous melanoma, especially in head and neck localizations where SLN biopsy is much more demanding. The benefits of SLN protocol are not proved yet. The aim of our study was to present our experience of SLN biopsy in head and neck cutaneous melanoma.

PATIENTS AND METHODS

This retrospective study included all patients managed for head and neck malignant melanoma from 2002 to 2006. We reviewed the technique, implementation and difficulties of the procedure, postoperative outcome, and complications.

RESULTS

Nineteen patients were included. An average of 2.2 lymph nodes were localized per patient using lymphoscintigraphy. Biopsy was impossible for one patient because the deep spinal node was not found. An average of 1.2 nodes was biopsied per patient. One patient presented with micrometastases. Another presented with lymphorrhea.

DISCUSSION

Sentinel node biopsy is widely performed in the management of cutaneous melanoma but remains an option for these indications in the last update of the French Society of Dermatology. SLN biopsy is difficult to implement because of the complexity of head and neck lymphatic system.

ARRDC3 suppresses breast cancer progression by negatively regulating integrin beta4

Large-scale genetic analyses of human tumor samples have been used to identify novel oncogenes, tumor suppressors and prognostic factors, but the functions and molecular interactions of many individual genes have not been determined. In this study we examined the cellular effects and molecular mechanism of the arrestin family member, ARRDC3, a gene preferentially lost in a subset of breast cancers. Oncomine data revealed that the expression of ARRDC3 decreases with tumor grade, metastases and recurrences. ARRDC3 overexpression represses cancer cell proliferation, migration, invasion, growth in soft agar and in vivo tumorigenicity, whereas downregulation of ARRCD3 has the opposite effects. Mechanistic studies showed that ARRDC3 functions in a novel regulatory pathway that controls the cell surface adhesion molecule, β-4 integrin (ITGβ4), a protein associated with aggressive tumor behavior. Our data indicates ARRDC3 directly binds to a phosphorylated form of ITGβ4 leading to its internalization, ubiquitination and ultimate degradation. The results identify the ARRCD3-ITGβ4 pathway as a new therapeutic target in breast cancer and show the importance of connecting genetic arrays with mechanistic studies in the search for new treatments.