S100A8/A9 predicts response to PIM kinase and PD-1/PD-L1 inhibition in triple-negative breast cancer mouse models

BACKGROUND

Understanding why some triple-negative breast cancer (TNBC) patients respond poorly to existing therapies while others respond well remains a challenge. This study aims to understand the potential underlying mechanisms distinguishing early-stage TNBC tumors that respond to clinical intervention from non-responders, as well as to identify clinically viable therapeutic strategies, specifically for TNBC patients who may not benefit from existing therapies.

METHODS

We conducted retrospective bioinformatics analysis of historical gene expression datasets to identify a group of genes whose expression levels in early-stage tumors predict poor clinical outcomes in TNBC. In vitro small-molecule screening, genetic manipulation, and drug treatment in syngeneic mouse models of TNBC were utilized to investigate potential therapeutic strategies and elucidate mechanisms of drug action.

RESULTS

Our bioinformatics analysis reveals a robust association between increased expression of immunosuppressive cytokine S100A8/A9 in early-stage tumors and subsequent disease progression in TNBC. A targeted small-molecule screen identifies PIM kinase inhibitors as capable of decreasing S100A8/A9 expression in multiple cell types, including TNBC and immunosuppressive myeloid cells. Combining PIM inhibition and immune checkpoint blockade induces significant antitumor responses, especially in otherwise resistant S100A8/A9-high PD-1/PD-L1-positive tumors. Notably, serum S100A8/A9 levels mirror those of tumor S100A8/A9 in a syngeneic mouse model of TNBC.

CONCLUSIONS

Our data propose S100A8/A9 as a potential predictive and pharmacodynamic biomarker in clinical trials evaluating combination therapy targeting PIM and immune checkpoints in TNBC. This work encourages the development of S100A8/A9-based liquid biopsy tests for treatment guidance.

S100A8/A9 predicts triple-negative breast cancer response to PIM kinase and PD-1/PD-L1 inhibition

It remains elusive why some triple-negative breast cancer (TNBC) patients respond poorly to existing therapies while others respond well. Our retrospective analysis of historical gene expression datasets reveals that increased expression of immunosuppressive cytokine S100A8/A9 in early-stage tumors is robustly associated with subsequent disease progression in TNBC. Although it has recently gained recognition as a potential anticancer target, S100A8/A9 has not been integrated into clinical study designs evaluating molecularly targeted therapies. Our small molecule screen has identified PIM kinase inhibitors as capable of decreasing S100A8/A9 expression in multiple cell types, including TNBC and immunosuppressive myeloid cells. Furthermore, combining PIM inhibition and immune checkpoint blockade induces significant antitumor responses, especially in otherwise resistant S100A8/A9-high PD-1/PD-L1-positive tumors. Importantly, serum S100A8/A9 levels mirror those of tumor S100A8/A9 in a syngeneic mouse model of TNBC. Thus, our data suggest that S100A8/A9 could be a predictive and pharmacodynamic biomarker in clinical trials evaluating combination therapy targeting PIM and immune checkpoints in TNBC and encourage the development of S100A8/A9-based liquid biopsy tests.

Oncogene-regulated release of extracellular vesicles

Oncogenes can alter metabolism by changing the balance between anabolic and catabolic processes. However, how oncogenes regulate tumor cell biomass remains poorly understood. Using isogenic MCF10A cells transformed with nine different oncogenes, we show that specific oncogenes reduce the biomass of cancer cells by promoting extracellular vesicle (EV) release. While MYC and AURKB elicited the highest number of EVs, each oncogene selectively altered the protein composition of released EVs. Likewise, oncogenes alter secreted miRNAs. MYC-overexpressing cells require ceramide, whereas AURKB requires ESCRT to release high levels of EVs. We identify an inverse relationship between MYC upregulation and activation of the RAS/MEK/ERK signaling pathway for regulating EV release in some tumor cells. Finally, lysosome genes and activity are downregulated in the context of MYC and AURKB, suggesting that cellular contents, instead of being degraded, were released via EVs. Thus, oncogene-mediated biomass regulation via differential EV release is a new metabolic phenotype.

A risk-associated Active transcriptome phenotype expressed by histologically normal human breast tissue and linked to a pro-tumorigenic adipocyte population

Background

Previous studies have identified and validated a risk-associated Active transcriptome phenotype commonly expressed in the cancer-adjacent and histologically normal epithelium, stroma, and adipose containing peritumor microenvironment of clinically established invasive breast cancers, conferring a 2.5- to 3-fold later risk of dying from recurrent breast cancer. Expression of this Active transcriptome phenotype has not yet been evaluated in normal breast tissue samples unassociated with any benign or malignant lesions; however, it has been associated with increased peritumor adipocyte composition.

Methods

Detailed histologic and transcriptomic (RNAseq) analyses were performed on normal breast biopsy samples from 151 healthy, parous, non-obese (mean BMI = 29.60 ± 7.92) women, ages 27–66 who donated core breast biopsy samples to the Komen Tissue Bank, and whose average breast cancer risk estimate (Gail score) at the time of biopsy (1.27 ± 1.34) would not qualify them for endocrine prevention therapy.

Results

Full genome RNA sequencing (RNAseq) identified 52% (78/151) of these normal breast samples as expressing the Active breast phenotype. While Active signature genes were found to be most variably expressed in mammary adipocytes, donors with the Active phenotype had no difference in BMI but significantly higher Gail scores (1.46 vs. 1.18; p = 0.007). Active breast samples possessed 1.6-fold more (~ 80%) adipocyte nuclei, larger cross-sectional adipocyte areas (p < 0.01), and 0.5-fold fewer stromal and epithelial cell nuclei (p < 1e−6). Infrequent low-level expression of cancer gene hotspot mutations was detected but not enriched in the Active breast samples. Active samples were enriched in gene sets associated with adipogenesis and fat metabolism (FDR q ≤ 10%), higher signature scores for cAMP-dependent lipolysis known to drive breast cancer progression, white adipose tissue browning (Wilcoxon p < 0.01), and genes associated with adipocyte activation (leptin, adiponectin) and remodeling (CAV1, BNIP3), adipokine growth factors (IGF-1, FGF2), and pro-inflammatory fat signaling (IKBKG, CCL13).

Conclusions

The risk-associated Active transcriptome phenotype first identified in cancer-adjacent breast tissues also occurs commonly in healthy women without breast disease who do not qualify for breast cancer chemoprevention, and independently of breast expressed cancer-associated mutations. The risk-associated Active phenotype appears driven by a pro-tumorigenic adipocyte microenvironment that can predate breast cancer development.

MYC Dysregulates Mitosis, Revealing Cancer Vulnerabilities

Tumors that overexpress the MYC oncogene are frequently aneuploid, a state associated with highly aggressive cancers and tumor evolution. However, how MYC causes aneuploidy is not well understood. Here, we show that MYC overexpression induces mitotic spindle assembly defects and chromosomal instability (CIN) through effects on microtubule nucleation and organization. Attenuating MYC expression reverses mitotic defects, even in established tumor cell lines, indicating an ongoing role for MYC in CIN. MYC reprograms mitotic gene expression, and we identify TPX2 to be permissive for spindle assembly in MYC-high cells. TPX2 depletion blocks mitotic progression, induces cell death, and prevents tumor growth. Further elevating TPX2 expression reduces mitotic defects in MYC-high cells. MYC and TPX2 expression may be useful biomarkers to stratify patients for anti-mitotic therapies. Our studies implicate MYC as a regulator of mitosis and suggest that blocking MYC activity can attenuate the emergence of CIN and tumor evolution.

Abstract P3-08-20: The normal breast Active transcriptome associated with future breast cancer risk is driven by a dysregulated adipocyte microenvironment

Background: Previous studies of breast samples from cosmetic surgeries, benign biopsies associated with abnormal mammograms or cancer-adjacent tissue have identified at least two different transcriptional phenotypes of “normal” human breast tissue (Troester, 2009; Haakensen, 2011), including an “Active” phenotype linked to increased risk of later breast cancer mortality (Roman-Perez, 2012; Troester, 2016). This study compares breast histology and transcriptional phenotypes from healthy parous women with no prior history of breast disease who donated breast core biopsies for research and supplied reproductive histories enabling breast cancer risk calculation. Since the Active transcriptome phenotype was recently associated with increased mammary adipocyte content, we focused on the possibility that adipocyte activation contributes to the Active transcriptome and drives breast cancer risk. Methods: RNA from paraffin-embedded tissue sections sufficient for RNAseq analysis (~100ng) was extracted from 151/200 core biopsies donated to the Komen Tissue Bank by healthy, parous white women (age range: 27-66, median = 45) with no history of breast cancer. Questionnaire data enabled breast cancer risk (Gail) score calculation; and digitized H&E images were used for histologic analyses. A previously validated classifying signature was used in unsupervised hierarchical clustering to identify samples with Active (78/151) vs. Inactive (73/151) transcriptome phenotypes for comparison with donor risk factors, breast tissue composition, and expression of candidate genes and gene signatures. Results: Mean (+/-SD) BMI and Gail score values were 29.60 (+/-7.92) and 1.27 (+/- 1.34), respectively; BMI scores were not significantly different by phenotype, but Gail scores were significantly higher for donors with an Active phenotype (1.46 vs. 1.18; p=0.007, Wilcoxon rank-sum). Active normal breast tissue samples possessed significantly more (%) adipocyte nuclei (p=3.9e-11) and greater adipocyte size (p&lt;0.01), with fewer (%) stromal (p=4.3e-7) and (%) epithelial (p=1.2e-10) nuclei. Differentially expressed genes between the Active and Inactive phenotypes were significantly enriched for gene sets (GSEA) involved in fat differentiation and metabolism (14% at FDR q≤10%). Signature scores for cAMP-dependent lipolysis (known to drive breast cancer progression), as well as white adipose tissue “browning,” were significantly higher (Wilcoxon p&lt;0.01) for the Active samples, as were specific genes reflecting adipocyte activation (leptin, adiponectin), remodeling (CAV1, BNIP3), adipokine growth factors (IGF-1, FGF2), and pro-inflammatory fat signaling (IKBKG, CCL13). Conclusion: In this cohort of predominantly non-obese women without breast disease, ~50% express an Active transcriptome phenotype previously linked to later-life breast cancer mortality. While &gt;80% of this donor cohort would not qualify for breast cancer chemoprevention, those with Active transcriptomes had significantly higher Gail scores supporting their increased future risk for breast cancer development. The Active breast transcriptome is strongly associated with increased adipocyte content, size, and overexpression of signatures and genes (including those previously linked to breast cancer progression) indicating a differentially activated adipocyte population. This dysregulated mammary adipocyte microenvironment not only appears to underlie the Active transcriptome phenotype but also precedes and potentially predicts the future histologic development of breast cancer.

Citation Format: Christopher C Benz, Taekyu Kang, Christina Yau, Chris Wong, Yulia Newton, Charlie Vaske, Stephen C Benz, Gregor Krings, Roman Camarda, Jill E Henry, Josh Stuart, Mark Powell. The normal breast Active transcriptome associated with future breast cancer risk is driven by a dysregulated adipocyte microenvironment [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-08-20.

Abstract 3314: Normal breast tissue at risk for cancer development: A breast cancer initiating role for mammary adipocytes

Adipocytes are the predominant cell population in the normal breast and while recent attention has pointed to adipocyte-tumor cell crosstalk as a driver of breast cancer biology there have been few reports on the potential role of adipocytes in driving breast cancer initiation. Because normal breast tissue studies have invariably used reduction mammoplasty, benign biopsy or cancer-adjacent tissues, we studied random breast core biopsy samples donated by 145 healthy, parous, non-obese, white women (median age = 45, range 27-66 y) without any history of breast cancer. Using questionnaire data to calculate future breast cancer risk (Gail scores), we compared digitized microscopic breast tissue (H&E) images with whole genome transcriptome profiling (RNAseq) from FFPE-extracted RNA. We used unsupervised hierarchical clustering of 1487 genes (normalized, median centered, log2-scaled RSEM values) to identify 32% of normal samples with an “Active” (vs. 68% “Inactive”) transcriptome phenotype previously associated with later-life risk of death from breast cancer. Despite slightly lower BMI values, donors with the Active transcriptome phenotype showed significantly higher Gail scores as well as higher mammary adipocyte nuclei counts (median 80% vs. 60%, p=2.3e-6). Tissue resident leukocytes were uncommon but Active transcriptome tissues expressed significantly altered immune modules enriched in TGFβ, interferon and macrophage gene signatures (including single gene increase in CD68) and depleted (relative to Inactive samples) of CD8+ T-cell and serum response/inflammation/wound healing signatures. Active samples were not enriched in cell senescence, SASP or DNA damage response gene signatures but were enriched in an autophagy-to-senescence-transition (AST) signature with increased CAV1 (caveolin-1, p=2.7e-12) and BNIP3 (Bcl2 interacting protein-3, p=4.7e-05) expression, genes that also regulate lipoprotein digestion/mobilization and adipocyte remodeling. Strongest among significant associations linking Active with adipocyte-enriched normal breast samples were increases in two adipokine growth factors, IGF-1 (p=2.2e-16) and FGF2 (p=3.0e-11), the adipokine (resistin) receptor CAP1 (p=0.04) recently linked to poor breast cancer outcomes, and a cAMP-dependent pro-lipolytic signature (p=0.01) known to drive breast cancer progression which, in these samples, correlated positively with average adipocyte area values. Altogether, the collective histologic and molecular features characterizing the normal breast tissue of &gt;30% of healthy parous and non-obese women with increased predicted breast cancer risk seem to implicate a dysregulated mammary adipocyte microenvironment similar to but distinct from that associated with established breast tumors, that precedes microscopic and clinical evidence of breast tumorigenesis.

Citation Format: Taekyu Kang, Christina Yau, Stephen Benz, Gregor Krings, Roman Camarda, Jill E. Henry, Mark Powell, Christopher C. Benz. Normal breast tissue at risk for cancer development: A breast cancer initiating role for mammary adipocytes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3314.

Abstract P3-09-01: MYC dysregulates mitotic spindle function in triple-negative breast cancer creating a dependency on TPX2

Tumors that overexpress the MYC oncogene, including most receptor triple-negative breast cancers, frequently demonstrate aneuploidy, numerical chromosome alterations associated with highly aggressive cancers. Aneuploidy is also associated with rapid tumor evolution and poor patient outcome. We identify that MYC overexpression induces reversible defects in microtubule nucleation and mitotic spindle assembly, in TNBCs and other epithelial cells, promoting chromosome segregation defects, micronuclei and chromosomal instability (CIN). High TPX2 expression is permissive for mitotic spindle assembly and chromosome segregation in cells with MYC overexpression; whereas TPX2 depletion blocks mitotic progression, induces cell death and prevents tumor growth. Attenuating MYC expression reverses mitotic defects, even in established breast tumor cell lines, implicating an ongoing role for high MYC in the persistence of CIN in cancers. Our studies implicate the MYC oncogene as a regulator of spindle assembly and identify a new MYC-TPX2 synthetic-lethal interaction in TNBC that could represent a future therapeutic strategy in MYC-overexpressing cancers. Moreover, our studies suggest that blocking MYC activity can attenuate the emergence of CIN and tumor evolution.

Citation Format: Goga A, Rohrberg J, Corella A, Taileb M, Kilinc S, Jokisch M-L, Camarda R, Zhou A, Balakrishnan S, Chang AN, Klein-Connolly H. MYC dysregulates mitotic spindle function in triple-negative breast cancer creating a dependency on TPX2 [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 P3-09-01.

Abstract 1462: The oncogene MYC induces chromosomal instability through dysregulating mitotic progression evoking a dependency on TPX2

More than 70% of common solid tumors are aneuploid. Aneuploidy has been implicated in tumorigenesis for decades. A direct cause of aneuploidy is chromosomal instability (CIN) that fuels tumor evolution by providing a heterogeneous subpopulation of cells that contributes to the lethal outcome of cancer, metastasis, therapeutic failure, and drug resistance. The oncogene c-MYC is overexpressed in many cancers and has been shown to induce structural and numerical chromosomal aberrations and aneuploidy. While the role of MYC in overcoming the G1/S checkpoint is well established, the role of MYC in altering mitotic dynamics and eliciting CIN remains poorly understood. Here, we identify a direct influence of increased MYC expression on mitotic progression and spindle assembly. We observe MYC-dependent microtubule nucleation and polymerization defects in mitosis. MYC overexpression induces altered spindle morphology promoting chromosome segregation defects resulting in micronuclei formation, CIN and aneuploidy. Importantly, attenuation of MYC expression reverses the mitotic defects observed, even in established tumor cell lines, implicating an ongoing role for MYC in the persistence of a CIN phenotype in tumors. Gene expression data reveal that MYC regulates numerous genes involved in mitosis, kinetochore function and microtubule behavior. We performed a screen to identify microtubule regulators required for the survival of MYC overexpressing cells. MYC overexpressing cells are reliant on high TPX2 expression, a master microtubule regulator. High TPX2 expression is permissive for mitotic spindle assembly and chromosome segregation in MYC high cells, while TPX2 depletion attenuates cell viability and tumor growth in vivo. Our data suggest that TPX2 is a transcriptional target of MYC. We postulate that high levels of TPX2 are required to tolerate mitotic stress induced by MYC. TPX2 compensates for impaired mitotic progression and prevents the development of physiologically intolerable levels of CIN. High levels of TPX2 might be required for tumors with oncogene-induced mitotic stress to faithfully proceed through mitosis providing an explanation for the abundant upregulation of TPX2 in cancer. Thus, we describe a conditional role for MYC in altering spindle assembly and dynamics, resulting in a dependency on TPX2 for tumor survival.

Citation Format: Julia Rohrberg, Alexandra Corella, Moufida Taileb, Marie-Lena Jokisch, Roman Camarda, Sanjeev Balakrishnan, Alicia Zhou, Andrei Goga. The oncogene MYC induces chromosomal instability through dysregulating mitotic progression evoking a dependency on TPX2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1462.

Abstract 2398: Tumor cell-adipocyte gap junctions activate lipolysis in breast cancer

During mammary tumorigenesis, a cell-cell interface exists between adipocytes and cancer cells. Several studies have demonstrated that breast tumor cells can secrete cytokines that induce lipolysis in adjacent adipocytes. However, evidence of tumor-adjacent lipolysis in clinical samples has been lacking. We therefore assayed for lipolysis in normal tissue adjacent to breast tumors (NAT) using (1) the three-component breast composition measure, a radiographic imaging method derived from dual-energy mammography that allows lipid content of a tissue to be quantified, on breast tumors and NAT from 46 patients, (2) a publically available dataset of gene expression in primary breast tumors and NAT from 9 patients, (3) laser capture microdissection and proteomics on primary breast tumors, stroma and NAT from 75 patients, and (4) immunoblot analysis of NAT from several patient-derived and transgenic mouse models of breast cancer. We found strong evidence in all cases that lipolysis is activated in breast cancer-adjacent adipose tissue. We next set out to model the breast cancer-adipocyte interface and determine the contribution of cell-cell contact to induced lipolysis. Gap junctions are cell-cell junctions formed by proteins called connexins, which are known to transport a variety of small molecules (&lt;1kD) including cAMP, a critical pro-lipolytic signaling molecule. Using established dye transfer assays, we determined that gap junctions form between breast cancer cells, and between breast cancer cells and adipocytes. Using biochemical assays, we demonstrated that cAMP is a substrate of breast cancer cell gap junctions, that transfer of cAMP from breast cancer cells to adipocytes occurs, and that breast cancer cells activate lipolytic signaling, all in a gap junction-dependent manner. Finally, we found that gap junction communication in this context is dependent upon connexin 31 (Cx31), and we establish the importance of Cx31 for breast tumor growth and activation of lipolysis in tumor-adjacent adipose tissue in vivo.

Citation Format: Roman Camarda, Jeremy Williams, Serghei Malkov, Lisa J. Zimmerman, Suzanne Manning, Dvir Aran, Andrew Beardsley, Daniel Van de Mark, Jeffrey van Haren, Yong Chen, Charles Berdan, Sharon Louie, Celine Mahieu, Juliane Winkler, Elizabeth Willey, John D. Gagnon, Kosaku Shinoda, K. Mark Ansel, Zena Werb, Daniel C. Nomura, Shingo Kajimura, Torsten Wittmann, Atul J. Butte, Melinda E. Sanders, Daniel C. Liebler, Gregor Krings, John A. Shepherd, Andrei Goga. Tumor cell-adipocyte gap junctions activate lipolysis in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2398.

In vivo Reprogramming of Cancer Metabolism by MYC

The past few decades have welcomed tremendous advancements toward understanding the functional significance of altered metabolism during tumorigenesis. However, many conclusions drawn from studies of cancer cells in a dish (i.e., in vitro) have been put into question as multiple lines of evidence have demonstrated that the metabolism of cells can differ significantly from that of primary tumors (in vivo). This realization, along with the need to identify tissue-specific vulnerabilities of driver oncogenes, has led to an increased focus on oncogene-dependent metabolic programming in vivo. The oncogene c-MYC (MYC) is overexpressed in a wide variety of human cancers, and while its ability to alter cellular metabolism is well-established, translating the metabolic requirements, and vulnerabilities of MYC-driven cancers to the clinic has been hindered by disparate findings from in vitro and in vivo models. This review will provide an overview of the in vivo strategies, mechanisms, and conclusions generated thus far by studying MYC's regulation of metabolism in various cancer models.

MYC-driven inhibition of the glutamate-cysteine ligase promotes glutathione depletion in liver cancer

How MYC reprograms metabolism in primary tumors remains poorly understood. Using integrated gene expression and metabolite profiling, we identify six pathways that are coordinately deregulated in primary MYC-driven liver tumors: glutathione metabolism; glycine, serine, and threonine metabolism; aminoacyl-tRNA biosynthesis; cysteine and methionine metabolism; ABC transporters; and mineral absorption. We then focus our attention on glutathione (GSH) and glutathione disulfide (GSSG), as they are markedly decreased in MYC-driven tumors. We find that fewer glutamine-derived carbons are incorporated into GSH in tumor tissue relative to non-tumor tissue. Expression of GCLC, the rate-limiting enzyme of GSH synthesis, is attenuated by the MYC-induced microRNA miR-18a. Inhibition of miR-18a in vivo leads to increased GCLC protein expression and GSH abundance in tumor tissue. Finally, MYC-driven liver tumors exhibit increased sensitivity to acute oxidative stress. In summary, MYC-dependent attenuation of GCLC by miR-18a contributes to GSH depletion in vivo, and low GSH corresponds with increased sensitivity to oxidative stress in tumors. Our results identify new metabolic pathways deregulated in primary MYC tumors and implicate a role for MYC in regulating a major antioxidant pathway downstream of glutamine.

Abstract 2673: Inhibition of fatty-acid oxidation as a therapy for MYC-overexpressing triple-negative breast cancer

Expression of the oncogenic transcription factor MYC is disproportionately elevated in triple-negative breast cancer (TNBC) compared to estrogen, progesterone and/or human epidermal growth factor 2 receptor-positive (RP) breast tumors. We and others have shown that MYC alters metabolism during tumorigenesis. However, the role of MYC in TNBC metabolism remains largely unexplored. We hypothesized that pharmacologic inhibition of MYC-driven metabolic pathways may serve as a therapeutic strategy for this clinically challenging subtype of breast cancer. Using a targeted metabolomics approach, we identified fatty-acid oxidation (FAO) intermediates as dramatically upregulated in a MYC-driven model of TNBC. A lipid metabolism gene signature was identified in patients with TNBC in the TCGA and multiple other clinical datasets, implicating FAO as a dysregulated pathway critical for TNBC metabolism. We find that MYC-overexpressing TNBC, including a transgenic model and patient-derived xenograft (PDX), display increased bioenergetic reliance upon FAO. Pharmacologic inhibition of FAO catastrophically decreases energy metabolism of MYC-overexpressing breast cancer, blocks growth of a MYC-driven transgenic TNBC model and MYC-overexpressing PDX. Our results demonstrate that inhibition of FAO is a novel therapeutic strategy against TNBCs that overexpress MYC.

Citation Format: Roman Camarda, Alicia Y. Zhou, Rebecca A. Kohnz, Sanjeev Balakrishnan, Celine Mahieu, Brittany Anderton, Henok Eyob, Shingo Kajimura, Aaron Tward, Gregor Krings, Daniel K. Nomura, Andrei Goga. Inhibition of fatty-acid oxidation as a therapy for MYC-overexpressing triple-negative breast cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2673.

Interictal Executive Dysfunction in Migraineurs Without Aura: Relationship With Duration and Intensity of Attacks

Subjects with migraine are at increased risk of subcortical white matter lesions (WML). Reports of cognitive testing in adults with migraine have yielded inconsistent results. We performed a cross-sectional study to assess whether migraine without aura (MwA) is associated with impairment in executive functioning, a typical cognitive correlate of subcortical WML. Forty-five subjects with MwA and 90 controls, matched for age and education, underwent a cognitive battery of tests evaluating executive functions. The following migraine characteristics were collected: age at onset and length of migraine history, and frequency, duration and intensity of attacks. Subjects with MwA performed significantly lower than controls in tests evaluating complex, multifactorial executive functions. After multiple adjustments, the duration and intensity of migraine attacks significantly predicted cognitive disturbances. In the interictal phase of MwA there is evidence of mild executive dysfunction. The cumulative effects of repeated migraine attacks on prefronto-cerebellar loop probably account for our results.

GSTP1 Is a Driver of Triple-Negative Breast Cancer Cell Metabolism and Pathogenicity

Breast cancers possess fundamentally altered metabolism that fuels their pathogenicity. While many metabolic drivers of breast cancers have been identified, the metabolic pathways that mediate breast cancer malignancy and poor prognosis are less well understood. Here, we used a reactivity-based chemoproteomic platform to profile metabolic enzymes that are enriched in breast cancer cell types linked to poor prognosis, including triple-negative breast cancer (TNBC) cells and breast cancer cells that have undergone an epithelial-mesenchymal transition-like state of heightened malignancy. We identified glutathione S-transferase Pi 1 (GSTP1) as a novel TNBC target that controls cancer pathogenicity by regulating glycolytic and lipid metabolism, energetics, and oncogenic signaling pathways through a protein interaction that activates glyceraldehyde-3-phosphate dehydrogenase activity. We show that genetic or pharmacological inactivation of GSTP1 impairs cell survival and tumorigenesis in TNBC cells. We put forth GSTP1 inhibitors as a novel therapeutic strategy for combatting TNBCs through impairing key cancer metabolism and signaling pathways.

Abstract PD3-05: Inhibition of fatty-acid oxidation as a therapy for triple-negative breast cancer

Expression of the oncogenic transcription factor MYC is disproportionately elevated in triple-negative breast cancer (TNBC) compared to estrogen, progesterone and/or human epidermal growth factor 2 receptor-positive (RP) breast tumors. We and others have shown that MYC alters metabolism during tumorigenesis. However, the role of MYC in TNBC metabolism remains largely unexplored. We hypothesized that pharmacologic inhibition of MYC-driven metabolic pathways may serve as a therapeutic strategy for this clinically challenging subtype of breast cancer. Using an unbiased metabolomics approach, we identified fatty acid oxidation intermediates as dramatically up-regulated in MYC-driven models of TNBC. A lipid metabolism gene signature was identified in patients with TNBC in the TCGA and multiple other clinical datasets, implicating fatty acid oxidation as a deregulated pathway critical for TNBC metabolism. We find that MYC-overexpressing TNBC, including transgenic models and patient-derived xenografts (PDX), display increased bioenergetic reliance upon fatty-acid oxidation (FAO). Pharmacologic inhibition of FAO catastrophically decreases energy metabolism of MYC over-expressing breast cancer, blocks growth of a MYC-driven transgenic TNBC model and MYC-overexpressing patient-derived xenografts. In vivo inhibition of FAO induced proliferation arrest and increased cell death in PDX models of TNBC. Our results demonstrate that inhibition of FAO is a novel therapeutic strategy against TNBCs that over-express MYC.

Citation Format: Goga A, Camarda R, Zhou AY, Kohnz RA, Balakrishnan S, Anderton B, Mahieu C, Eyob H, Krings G, Nomura DK. Inhibition of fatty-acid oxidation as a therapy for triple-negative breast cancer. [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 PD3-05.

Abstract B34: PIM kinase as a novel therapeutic target for triple-negative breast cancer

The greatest clinical challenge in treating breast cancer occurs in those patients whose tumors lack expression of the estrogen and progesterone receptors and that of the HER2 oncoprotein. No targeted therapeutic strategies currently exist against this aggressive type of “triple negative” breast cancer (TNBC) due to lack of validated targets. We previously found that MYC mRNA, protein, and its signaling were disproportionally elevated in TN compared to receptor positive (RP) breast cancer. We sought to take advantage of the unique molecular feature found in this tumor type to identify potent and effective treatment strategies. Since MYC is an oncogenic transcription factor, rationally designed small molecule inhibitors that can directly inhibit its activity are not available for clinical use. An alternative approach to selectively kill MYC-driven tumors is to inhibit those proteins that are indispensable for the viability of such tumors, but are not essential in non-tumorigenic cells. This form of “indirect” treatment strategy has become known as the “synthetic-lethal” approach. To identify novel targets that are readily druggable for treating MYC-driven TNBC, we conducted a kinome MYC synthetic lethal shRNA screen in non-immortalized human mammary epithelial cells expressing a 4-hydroxytamoxifen (TAM)-activatable MycER transgene (HMEC-MycER). Of 600 human kinases targeted by 2,000 individual shRNA clones, 9 kinases were identified as hits as they were essential specifically for the MYC-activated HMEC cells. Among these hits, we focused on PIM1, a non-essential kinase, the knock-down of which had the greatest efficacy in causing cell death in the MYC-activated cells and had minimum inhibitory effect on the growth of the control cells. We determined that PIM1 expression was elevated in TN tumors and was associated with poor prognosis specifically in patients with hormone receptor-negative tumors. Small molecule PIM kinase inhibitors halted the growth of human TN tumors with elevated MYC expression in a patient-derived tumor xenograft (PDX) mouse model by inhibiting oncogenic transcriptional activity of MYC while simultaneously restoring the function of the endogenous cell cycle inhibitor p27. Thus, our findings warrant clinical evaluation of small molecule PIM kinase inhibitors in patients with TN tumors that exhibit elevated MYC expression.

Note: This abstract was not presented at the conference.

Citation Format: Dai Horiuchi, Alicia Y. Zhou, Alexandra N. Corella, Christina Yau, Sanjeev Balakrishnan, Kai Kessenbrock, Devon A. Lawson, Roman Camarda, Brittany N. Anderton, Alexey V. Bazarov, Henok Eyob, Julia Rohrberg, Paul Yaswen, Michael T. McManus, Hope S. Rugo, Zena Werb, Andrei Goga. PIM kinase as a novel therapeutic target for triple-negative breast cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research; Oct 17-20, 2015; Bellevue, WA. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(2_Suppl):Abstract nr B34.

Multiple breast cancer risk variants are associated with differential transcript isoform expression in tumors

Genome-wide association studies have identified over 70 single-nucleotide polymorphisms (SNPs) associated with breast cancer. A subset of these SNPs are associated with quantitative expression of nearby genes, but the functional effects of the majority remain unknown. We hypothesized that some risk SNPs may regulate alternative splicing. Using RNA-sequencing data from breast tumors and germline genotypes from The Cancer Genome Atlas, we tested the association between each risk SNP genotype and exon-, exon–exon junction- or transcript-specific expression of nearby genes. Six SNPs were associated with differential transcript expression of seven nearby genes at FDR < 0.05 (BABAM1, DCLRE1B/PHTF1, PEX14, RAD51L1, SRGAP2D and STXBP4). We next developed a Bayesian approach to evaluate, for each SNP, the overlap between the signal of association with breast cancer and the signal of association with alternative splicing. At one locus (SRGAP2D), this method eliminated the possibility that the breast cancer risk and the alternate splicing event were due to the same causal SNP. Lastly, at two loci, we identified the likely causal SNP for the alternative splicing event, and at one, functionally validated the effect of that SNP on alternative splicing using a minigene reporter assay. Our results suggest that the regulation of differential transcript isoform expression is the functional mechanism of some breast cancer risk SNPs and that we can use these associations to identify causal SNPs, target genes and the specific transcripts that may mediate breast cancer risk.

Abstract A03: Integrative analyses reveal distinct metabolic dysregulation in MYC-driven, basal breast cancer

Dysregulated metabolism is a hallmark of all human cancers. The observation that tumors display unique changes in metabolism led to the hypothesis that tumors may be dependent upon an altered metabolic state. c-MYC (MYC) is a proto-oncogene and transcription factor activated in many cancers that regulates multiple metabolic pathways. Our lab and others have shown that MYC is activated in a large proportion of basal-like breast cancer, the most aggressive subtype of human breast cancer. However, the role of MYC in basal breast cancer metabolism is largely unknown. No efficacious MYC inhibitor is available for clinical use, however, an alternative treatment strategy is to target cellular pathways required in the context of MYC activation. We hypothesize that basal-like breast cancer harbors distinct, MYC-driven metabolic dysregulation, and that this dysregulation can be targeted therapeutically to induce MYC-dependent synthetic lethality. Utilizing in vitro and in vivo models of MYC-driven and basal breast cancer, including patient-derived cell lines and patient-derived xenograft mouse tumor models, we have performed metabolomic and transcriptomic analyses. We investigate MYC-dependent metabolic dysregulation via integrated analyses of these datasets, and find distinct changes that could reveal essential metabolic pathways for MYC-driven, basal tumorigenesis.

Citation Format: Roman Camarda, Sanjeev Balakrishnan, Alicia Y. Zhou, Brittany Anderton, Henok Eyob, Rebecca Kohnz, Daniel K. Nomura, Andrei Goga. Integrative analyses reveal distinct metabolic dysregulation in MYC-driven, basal breast cancer. [abstract]. In: Proceedings of the AACR Special Conference on Myc: From Biology to Therapy; Jan 7-10, 2015; La Jolla, CA. Philadelphia (PA): AACR; Mol Cancer Res 2015;13(10 Suppl):Abstract nr A03.

Global metabolic profiling of infection by an oncogenic virus: KSHV induces and requires lipogenesis for survival of latent infection

Like cancer cells, virally infected cells have dramatically altered metabolic requirements. We analyzed global metabolic changes induced by latent infection with an oncogenic virus, Kaposi's Sarcoma-associated herpesvirus (KSHV). KSHV is the etiologic agent of Kaposi's Sarcoma (KS), the most common tumor of AIDS patients. Approximately one-third of the nearly 200 measured metabolites were altered following latent infection of endothelial cells by KSHV, including many metabolites of anabolic pathways common to most cancer cells. KSHV induced pathways that are commonly altered in cancer cells including glycolysis, the pentose phosphate pathway, amino acid production and fatty acid synthesis. Interestingly, over half of the detectable long chain fatty acids detected in our screen were significantly increased by latent KSHV infection. KSHV infection leads to the elevation of metabolites involved in the synthesis of fatty acids, not degradation from phospholipids, and leads to increased lipid droplet organelle formation in the infected cells. Fatty acid synthesis is required for the survival of latently infected endothelial cells, as inhibition of key enzymes in this pathway led to apoptosis of infected cells. Addition of palmitic acid to latently infected cells treated with a fatty acid synthesis inhibitor protected the cells from death indicating that the products of this pathway are essential. Our metabolomic analysis of KSHV-infected cells provides insight as to how oncogenic viruses can induce metabolic alterations common to cancer cells. Furthermore, this analysis raises the possibility that metabolic pathways may provide novel therapeutic targets for the inhibition of latent KSHV infection and ultimately KS tumors.

In recent years there has been a resurgence in the study of metabolic changes in tumor cells. To determine if an oncogenic virus alters similar metabolic pathways as cancer cells, we measured the levels of a large number of metabolites in endothelial cells infected with Kaposi?s Sarcoma-associated herpesvirus (KSHV). KSHV is the etiologic agent of Kaposi's Sarcoma (KS), the most common tumor of AIDS patients world wide. Latent KSHV infection of endothelial cells altered a significant proportion of the host cell metabolites. Many metabolic pathways that are altered in most tumor cells were also altered by KSHV. In particular, KSHV upregulated fatty acid synthesis, a pathway that provides membrane material and metabolites critical for cell proliferation. Inhibitors of fatty acid synthesis kill many types of tumor cells and we found that these inhibitors led to death of cells latently infected with KSHV. In summary, we found that a directly oncogenic virus alters the same host metabolic pathways that are dysregulated in many cancer cells and that inhibition of these pathways can be used to kill off infected cells, thereby providing novel therapeutic targets for KSHV and ultimately KS tumors.

Neuropsychiatric symptoms in 921 elderly subjects with dementia: a comparison between vascular and neurodegenerative types

OBJECTIVE

i) to describe the neuropsychiatric profile of elderly subjects with dementia by comparing vascular (VaD) and degenerative dementias, i.e. dementia with Lewy bodies (DLB) and Alzheimer's disease (AD); ii) to assess whether the severity and type of dementia are associated with clinically relevant neuropsychiatric symptoms (CR-NPS).

METHOD

One hundred and thirty-one out-patients with VaD, 100 with DLB and 690 with AD were studied. NPS were evaluated by the neuropsychiatric inventory (NPI).

RESULTS

Vascular dementia had lower total and domain-specific NPI scores and a lower frequency of CR-NPS than AD and DLB, for which frequency of CR-NPS increased significantly with disease severity, particularly in AD. Logistic regression analysis showed that a higher CDR score and a diagnosis of degenerative dementia were independently associated with CR-NPS.

CONCLUSION

Vascular dementia is associated less with CR-NPS than AD and DLB. Frequency of CR-NPS increases with disease severity in AD and, to a lesser extent, in DLB.

Association between apolipoprotein E epsilon4 allele and apathy in probable Alzheimer's disease

OBJECTIVE

There have been inconclusive results to date on the association between the Apolipoprotein E (ApoE) genotype and neuropsychiatric symptoms (NPS) in Alzheimer's disease (AD). We investigated whether ApoE epsilon4 allele is associated with NPS in probable AD.

METHOD

Data for 197 subjects with probable AD were analysed. The Neuropsychiatric Inventory was used to evaluate the frequency and severity of NPS. Multiple logistic regression models were used to test the association between ApoE genotype and NPS in AD.

RESULTS

The ApoE epsilon3/3 genotype was present in 52.3%, epsilon3/4 in 44.1%, and epsilon4/4 in 3.6% of patients. ApoE epsilon4 carriers showed a higher frequency of apathy than non-carriers. After multiple adjustments, the ApoE epsilon4 allele was significantly associated with apathy.

CONCLUSION

Our results suggest a relationship between the ApoE epsilon4 allele and apathy in patients with AD.

A novel mutation of the extracellular matrix protein 1 gene (ECM1) in a patient with lipoid proteinosis (Urbach-Wiethe disease) from Sicily

BACKGROUND

Lipoid proteinosis (LP), also known as Urbach-Wiethe disease, is a rare autosomal recessive disorder characterized by a hoarse voice, warty skin infiltration and scarring. Mutations within the extracellular matrix protein 1 (ECM1) gene cause LP.

OBJECTIVES

We report the molecular analysis of the ECM1 gene in a Sicilian patient with LP in order to extend the mutation spectrum of this genodermatosis.

METHODS

We studied a 32-year-old female born from consanguineous parents who was diagnosed at the age of 11 years as having LP. She has a clinical phenotype corresponding to Urbach-Wiethe disease characterized by papules/nodules, indurated plaques and sometimes ulcerated lesions primarily involving the skin and mucous membranes, and extracutaneous features such as epilepsy, hoarseness of the voice and neuropsychiatric abnormalities. Samples of clinically affected skin obtained by biopsies were analysed after staining with haematoxylin and eosin, periodic acid-Schiff (PAS), and PAS-diastase. The whole ECM1 gene was analysed by direct sequencing.

RESULTS

We identified a homozygous nonsense mutation in exon 6 of the ECM1 gene, C589T (Q197Ter).

CONCLUSIONS

Over 60% of mutations occur in exons 6 and 7. Exon 7 is alternatively spliced and frameshift mutations in exon 7 lead to ablation of the ECM1a transcript, but not the shorter ECM1b transcript that normally lacks this exon. Homozygous nonsense or frameshift mutations in exon 6 are predicted to affect both full-length ECM1a and ECM1b transcripts, whereas ECM1b should be unaffected for similar types of mutation in exon 7. It has been suggested that individuals with mutations in exon 7 have a slightly milder phenotype than those with exon 6 mutations. This is the first report with respect to a novel mutation of the ECM1 gene responsible for recessive LP in Sicily.

Effects of levodopa oral bolus on the kinematics of the pointing movements in Parkinson's disease patients

We studied the time-course of a levodopa oral bolus effects on the kinematics of patients affected by a mild akinetic-rigid form of idiopathic Parkinson's disease (PD). Eleven PD patients were evaluated: a) in OFF-state, that is before their first medication or after its withdrawal, b) in ON-state, that is at 1/2, 1, 2, 3, 4, 5, 6, 24, 30 and 48 hours after the administration of 250 mg of levodopa plus 25mg of carbidopa. The main kinematics (i. e.movement time, peak of velocity, peak of acceleration and peak of deceleration) of pointing movements to six target-stimuli placed on the horizontal plane of a table were recorded. Clinical conditions were assessed according to the Motor Examination section of the Unified Parkinson's Disease Rating Scale. The levopoda bolus had stable clinical effects only within the first six hours from its administration. The decline of the clinical response was marked by the changes of peak acceleration whereas other kinematics (i. e. movement time and the peak of velocity) changed also in the late observations (24, 30 and 48 hours after drug intake). The dissociation between the persistent improvement on movement time on peak velocity and the rapid deterioration of levodopa effects on early kinematics (i. e. peak acceleration) could be accounted for by a progressive decline in movement programming.

Prevalence of primary headaches in Italian elderly: preliminary data from the Zabút Aging Project

We describe preliminary 1-year prevalence data of recurrent migraine headache (MH), tension-type headache (TTH), and other headaches (OH) in a rural elderly population. A door-to-door two-phase survey was conducted on all elderly (>or=65 years) residents of a rural village in southern Italy. Participants underwent a two-phase screening including a validated semi-structured questionnaire for headaches based on the International Headache Society criteria, and a neurological evaluation. Recurrent headache was defined as 3 or more attacks within the past 12 months. Out of 1031 participants evaluated, 225 (21.8%) suffered from recurrent headaches. One-year prevalence rates for headaches were respectively 4.6% for MH, 16% for TTH, and 1.3% for OH. For MH and TTH, but not for OH, prevalence rates were significantly higher for women than for men. Only MH prevalence rates significantly decrease with increasing age. In our population, about one-fifth of elderly subjects suffered from recurrent primary headaches. Prevalence rates were higher in women, and tended to decline with increasing age.

Prevalence of headache in patients with Behçet's disease without overt neurological involvement

The aims of the present study were to evaluate the prevalence of headache and the frequency of different headache syndromes in patients with Behçet's Disease (BD) without neurological involvement and to investigate the relationship with other clinical, and behavioural variables. Twenty-seven BD patients and 27 control subjects underwent a validated semistructured questionnaire based on the International Headache Society criteria. Levels of anxiety and depression, disease activity, and current medication were collected. Headache occurred in 88.9% of BD patients. There was no difference in the prevalence of the different headache syndromes between BD patients and controls. Only migraine without aura (MwA) was significantly more frequent in BD patients than controls (44.4% vs. 11.1%, respectively, P= 0.013). No relationship was found between MwA and clinical, and behavioural variables. Among headache syndromes, MwA showed the highest frequency in BD. A vascular or neuronal subclinical dysfunction could justify this association. A careful interview for migraine might be included in the diagnostic work-up of BD.

Prevalence and pattern of cognitive impairment in systemic lupus erythematosus patients with and without overt neuropsychiatric manifestations

The prevalence and pattern of cognitive impairment in systemic lupus erythematosus (SLE) patients with (NPSLE) and without (nSLE) overt neuropsychiatric manifestations were investigated. Fifty-two nSLE patients, 23 NPSLE patients and 27 healthy controls were evaluated with a battery of standardized neuropsychological and psychological tests. Disease duration, disease activity index, and current corticosteroid therapy were collected. Cognitive impairment was identified in 14 (26.9%) and in 12 (52.2%) of subjects with nSLE and NPSLE, respectively. Both SLE groups showed a significant impairment compared with controls on tasks assessing verbal and non-verbal long-term memory, and visuoconstructional abilities. In addition, NPSLE patients reported worse performances than both nSLE patients and controls on task evaluating short-term visuospatial memory. NPSLE subjects were significantly more anxious and depressed compared to both nSLE subjects and controls. By multivariate analysis, only depression levels, among clinical variables, significantly predicted cognitive performance. This study shows that cognitive impairment occurs frequently in both nSLE and NPSLE subjects. The higher frequency in NPSLE may be related to coexisting depressive disturbances.

Cognitive deficits in beta-thalassemia major

OBJECTIVES

To assess cognitive functioning in patients affected by beta-thalassemia major (beta-th) by using a neuropsychological battery, and to identify clinical correlates.

MATERIAL AND METHODS

Forty-six beta-th patients and 46 controls similar for age, sex, and education participated in the study. All subjects performed a comprehensive neuropsychological battery including tests of abstract reasoning, attention, executive functions, language, constructional/visuospatial skills, and memory.

RESULTS

Compared to controls beta-th patients, in particular those showing signs of hemosiderosis, were significantly impaired on all neuropsychological tests. There was no relationship between cognitive performances and signs of deferoxamine toxicity, deferoxamine dosage, and levels of hemoglobin and ferritin, while duration of transfusional therapy and time interval between onset of blood transfusions and onset of chelating treatment correlated with performances of tests assessing abstract reasoning, attention, constructional/visuospatial skills, memory and with the scores of the Mini Mental State Examination.

CONCLUSION

Our findings suggest that beta-th is associated with neuropsychological impairment involving multiple cognitive domains and argue for a potential role of hemosiderosis on cognitive functioning.

The IHS classification criteria for migraine headaches in adolescents need minor modifications

The operational and diagnostic criteria for migraine and all other headache disorders released in 1988 by the International Headache Society are universally considered reliable and exhaustive. These criteria, however, cannot be considered as satisfactory for population-based studies on migraine prevalence, especially if adolescents are the subjects of the study. Using these diagnostic criteria, we conducted an epidemiological study in order to assess the prevalence of migraine headache in a student population aged 11 to 14 years. Our survey made it possible to code IHS 1.1 (migraine without aura) in 2.35%, IHS 1.2 (migraine with aura) in 0.62%, IHS 1.7 (migrainous disorders not fulfilling migraine criteria) in 1.52%, and IHS 13 (headache not classifiable) in 1.38% of the examined pupils. In adolescents, the low prevalence estimates of migraine headache coded IHS 1.1 and the relatively high prevalence estimates of headaches coded IHS 1.7 and IHS 13 have appeared to be a consequence of the rigidity of some operational diagnostic criteria of the recent IHS classification rather than of the geographical, environmental, or socioeconomical peculiarities of the cohort. Therefore, in order to improve the reliability and the exhaustiveness of the IHS classification by increasing its sensitivity, we believe that minor modifications of the diagnostic criteria are necessary. Within these revised criteria, the subitem "moderate or severe intensity" of pain headache should become mandatory, whereas the lower limit of the criterion "duration of pain" should be reduced to 1 hour.

Transient topographical amnesia and cingulate cortex damage: a case report

Transient topographical amnesia (TTA) is the temporary inability to find one's way in familiar or unfamiliar surroundings due to the inability to use well known environmental landmarks for route finding. The syndrome has not been described as having any obvious aetiology and has been thought to be caused by a vascular deficit in right hemispheric structures which are crucial for topographic recognition, i.e. parietal association and parahippocampal cortex. The patient described in the present study complained of several critical episodes of TTA and tonic rigidity of the left limbs. Neuropsychological assessment was normal except for a deficit in spatial memory tasks. Magnetic resonance (MR) imaging of the brain showed an angioma at the border of areas 24d and 23 of the right cingulate cortex. Because area 23 is strategically located in a network that links the parietal associative (area 7a) and parahippocampal cortices, and because these cortical areas are involved in topographical orienting processes, we suggest that a transient functional inactivation of the network caused by epileptic discharges spreading from the damaged cingulate cortex towards the parahippocampal and parietal association cortex could account for the spatial disorder. Similar discharges spreading from area 24d towards the primary motor cortex and/or the spinal cord could account for the episodes of tonic rigidity of the left limbs.

Migraine headaches in adolescents: a student population-based study in Monreale

We assessed the prevalence of migraine headaches in an epidemiological survey of an 11 to 14-year-old student population. Migraine headaches were classified on the basis of questionnaires and neurological examination using the operational diagnostic criteria of the International Headache Society. Prevalence of migraine without aura (IHS code 1.1) was 2.35%; that of migraine with aura (IHS code 1.2) was 0.62%. Migraine without aura was equally distributed among males and females, whereas migraine with aura was preponderant in the female cohort. The prevalence of migraine headaches in males was constant through the ages studied, whereas the prevalence of migraine headaches in females reached a peak at age 12 and plateaued over the following two years. Although the new IHS classification criteria of migraines are reliable and exhaustive, some subcriteria may not be valid in a juvenile population. For instance, the duration of the pain in young migraineurs is often briefer than in adults, and the intensity of pain was almost always described as moderate or severe. Therefore, in order to increase the reliability and comprehensiveness of the IHS classification, minor modifications should be made.

Corticospinal projections from mesial frontal and cingulate areas in the monkey

We injected neural tracers into the lateral funiculus of the spinal cord in order to relate the sites of origin of the spinal projections from the mesial cortical surface with the cytoarchitectonic organization of this region. We found a close correlation between the origin sites and density of corticospinal projections and the areal organization. The areas most densely labelled were F3 (SMA-proper) and area 24d, whereas F6 (pre-SMA) and area 24c showed a low density of labelling. The segmental topography of the corticospinal projections fitted well with the somatotopy of the mesial cortical areas. We conclude that in the agranular mesial cortex there are four independent motor representations: F3 and 24d where the whole body is represented, and F6 and 24c which are mostly related to arm movements.

Monosymptomatic presentation of type I Arnold-Chiari malformation: report of two cases

Two cases of type I ACM are described, one of which presented with dizziness in late childhood (case 1), the other with mild intention tremor in adulthood (case 2). Cerebellar ectopia should be considered in monosymptomatic patients even in the absence of other symptoms and signs of C.N.S. dysfunction. Magnetic resonance imaging of the craniocervical junction should be performed because it may be diagnostic for type I ACM.

Corticocortical connections of area F3 (SMA-proper) and area F6 (pre-SMA) in the macaque monkey

The monkey mesial area 6 comprises two distinct cytoarchitectonic areas: F3 [supplementary motor area properly defined (SMA-proper)], located caudally, and F6 (pre-SMA), located rostrally. The aim of the present study was to describe the corticocortical connections of these two areas. To this purpose restricted injections of neuronal tracers (wheat germ-agglutinin conjugated to horseradish peroxidase, fluorescent tracers) were made in different somatotopic fields of F3, F6, and F1 (area 4) and their transport plotted. The results showed that F3 and F6 differ markedly in their cortical connections. F3 is richly linked with F1 and the posterior premotor and cingulate areas (F2, F4, 24d). Connections with the anterior premotor and cingulate areas (F6, F7, F5, 24c) although present, are relatively modest. There is no input from the prefrontal lobe. F3 is also connected with several postrolandic cortical areas. These connections are with areas PC, PE, and PEa in the superior parietal lobule, cingulate areas 23 and PEci, the opercular parietal areas (PFop, PGop, SII) and the granular insula. F6 receives a rich input from the anterior premotor areas (especially F5) and cingulate area 24c, whereas its input from the posterior premotor and cingulate areas is very weak. A strong input originates from area 46. There are no connections with F1. The connections with the postrolandic areas are extremely meagre. They are with areas PG and PFG in the inferior parietal lobule, the disgranular insula, and the superior temporal sulcus. A further result was the demonstration of a differential connectivity pattern of the cingulate areas 24d and 24c. Area 24d is strongly linked with F1 and F3, whereas area 24c is connected mostly with F6. The present data support the notion that the classical SMA comprises two functionally distinct areas. They suggest that F6 (the rostral area) is responsible for the "SMA" so-called high level motor functions, whereas F3 (the caudal area) is more closely related to movement execution.

Somatotopic representation in inferior area 6 of the macaque monkey

On the basis of its cytoarchitectonic and enzymatic properties area 6 of the macaque monkey can be subdivided into two large sectors: a superior sector lying medial to the spur of the arcuate sulcus (superior area 6 or F2) and an inferior sector lying lateral to it (inferior area 6). Inferior area 6 is constituted by two enzymatic areas: F4 and F5. In this study we investigated the somatotopic organization of inferior area 6 and the adjacent area 4 combining single-neuron recording and intracortical electrical microstimulation. We found that two separate movement representations exist in this region. The caudal one corresponds to area F1 (primary motor cortex), the rostral one to inferior area 6. The two representations are mirror images one of the other with the axioproximal movements being adjacently located. In the rostral map the proximal movements are mostly located in F4, the distal movements in F5. Neuronal properties indicate that the rostral map has characteristics that are more complex than the caudal map. We propose that the rostral map is involved in transforming visual information in motor commands. F4 should be involved in the control of arm movements based on the location of the objects in respect to the body, whereas F5 should play a role in the control of grasping movements on the basis of the size of the stimuli.

Functional organization of inferior area 6 in the macaque monkey. I. Somatotopy and the control of proximal movements

Two series of experiments are reported in this paper. The first concerns the movement representation in the macaque inferior area 6, the second the functional properties of neurons located in the caudal part of this area (histochemical area F4). By combining single neuron recording and intracortical microstimulation, we found that inferior area 6 is somatotopically organized. The axio-proximal movements are represented caudally, the distal movements are represented near the arcuate sulcus. The mouth field is located laterally, the hand field medially. There is no leg field. A comparison between neuron properties and histochemical characteristics of inferior area 6 showed that the proximal movements representation includes most of area F4, whereas the distal movements representation corresponds to area F5 and to the rostral part of F4. Neurons located in that part of F4 where proximal movements are represented respond very well to tactile stimuli. They have large receptive fields mostly located on the face and on the upper part of the body. A large number of these neurons respond to visual stimuli. Objects approaching the animal are particularly effective. The tactile and the visual receptive fields are in register. The most represented movements are reaching movements, movements bringing the hand to the mouth or to the body and facial movements. There is a congruence between location of visual fields and preferred arm movements. It is argued that the receptive field arrangement and the response properties are more complex in area F4 than in the primary motor cortex and that area F4 neurons are involved in the control of arm movements towards different space sectors.

Functional organization of inferior area 6 in the macaque monkey. II. Area F5 and the control of distal movements

The functional properties of neurons located in the rostral part of inferior area 6 were studied in awake, partially restrained macaque monkeys. The most interesting property of these neurons was that their firing correlated with specific goal-related motor acts rather than with single movements made by the animal. Using the motor acts as the classification criterion we subdivided the neurons into six classes, four related to distal motor acts and two related to proximal motor acts. The distal classes are: "Grasping-with-the-hand-and-the-mouth neurons", "Grasping-with-the-hand neurons", "Holding neurons" and "Tearing neurons". The proximal classes are: "Reaching neurons" and "Bringing-to-the-mouth-or-to-the-body neurons". The vast majority of the cells belonged to the distal classes. A particularly interesting aspect of distal class neurons was that the discharge of many of them depended on the way in which the hand was shaped during the motor act. Three main groups of neurons were distinguished: "Precision grip neurons", "Finger prehension neurons", "Whole hand prehension neurons". Almost the totality of neurons fired during motor acts performed with either hand. About 50% of the recorded neurons responded to somatosensory stimuli and about 20% to visual stimuli. Visual neurons were more difficult to trigger than the corresponding neurons located in the caudal part of inferior area 6 (area F4). They required motivationally meaningful stimuli and for some of them the size of the stimulus was also critical. In the case of distal neurons there was a relationship between the type of prehension coded by the cells and the size of the stimulus effective in triggering the neurons. It is proposed that the different classes of neurons form a vocabulary of motor acts and that this vocabulary can be assessed by somatosensory and visual stimuli.

Afferent and efferent projections of the inferior area 6 in the macaque monkey

The rostral part of the agranular frontal cortex (area 6) can be subdivided on the basis of its cytoarchitecture, enzymatic properties, and connections into two large sectors: a superior region, lying medial to the spur of the arcuate sulcus, and an inferior region, lying lateral to it. In this study we traced the afferent and efferent connections of the inferior region of area 6 by injecting small amounts of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) and fluorescent tracers (fast blue and diamidino yellow) into restricted parts of inferior area 6 and in physiologically determined fields of area 4. There is an ordered topographic pattern of connections between inferior area 6 and area 4. The region near the spur of the arcuate sulcus (hand field) projects to the area 4 hand field while the lateral part of inferior area 6 (mouth field) is connected with the corresponding field in area 4. The organization of the connections between the two fields is, however, different. The hand fields in area 6 and 4 have direct reciprocal projections, whereas the mouth field in the postarcuate cortex relays information to area 4 via a zone intermediate between the arcuate and the central sulcus. This zone corresponds to the cytochrome oxidase area F4 (Matelli, Luppino, and Rizzolatti: Behav. Brain Res. 18: 125-137, '85). The inferior area 6 also has topographically organized connections with the supplementary motor area. The inferior area 6 receives and sends fibers to a series of discrete cortical areas located in the lower cortical moiety (Sanides: The Structure and Function of the Nervous Tissue, Vol. 5. New York: Academic Press, pp 329-453, '72). These areas that form a broad ring around the central sulcus are the ventral bank of the principal sulcus and the adjacent area 46, the precentral operculum (PrOC), area SII (Jones and Burton: J. Comp. Neurol. 168:197-248, '76), the parietal operculum, and the rostral part of the inferior parietal lobule including the lower bank of the intraparietal sulcus. Finally, the inferior area 6 has sparse but consistent connections with insular and cingulate cortices. The functional significance of this complex pattern of connections is discussed.

Interconnections within the postarcuate cortex (area 6) of the macaque monkey

Small amounts of horseradish peroxidase conjugated with wheat germ were injected in restricted parts of the postarcuate premotor area of the macaque monkey. It was found that regions of this area having different somatotopic representations are richly interconnected among them. This pattern of intra-areal connectivity was not observed in the precentral motor area. It appears therefore that the postarcuate area is organized according to anatomical principles which are different from those of the primary motor cortex.

[Intrinsic and extrinsic connections of the postarcuate premotor area of the monkey]

Horseradish peroxidase conjugated with wheat germ agglutinine was injected in restricted parts of the postarcuate cortex in the macaque monkey. Anterograde and retrograde transport was found in the parietal and frontal lobes. In the parietal lobe two areas were marked: the antero-lateral part of area 7 and the superior bank of the sylvian fissure. In the frontal lobe the marked areas were the precentral motor cortex, the supplementary motor area and the gyrus cinguli. The intrinsic connections within the postarcuate cortex were rich and widespread. The hand representation was connected anterogradely and retrogradely with the mouth representation and anterogradely with the leg representation; the mouth representation was connected both ways with the hand representation but not with the leg area. The richness of intrinsic connections in the postarcuate cortex supports the suggestion that this area is involved in the organization of sequential motor acts.

[Functional organization of the intermediate and deep layers of the superior colliculus of the monkey]

Single neurons and polispike activity were recorded from the superior colliculus of anesthetized, behaving monkeys. In agreement with previous findings neurons of the superficial layers responded exclusively to visual stimuli. In the intermediate layers most neurons were oculomotor, although some of them showed also a visual receptive field. No neurons responding to tactile or auditory stimuli were found. Occasionally the discharge of an oculomotor neuron increased if the ocular movement was triggered by a visual or an acoustical stimulus. Rare tacticle and auditory neurons were recorded in deep layers. However their receptive fields were difficult to map and their responses lacked the precision of the responses of the specific acoustic and tactile areas. Electrical stimulation of the SC produced contralateral eye and head movements, the threshold being high in the superficial layers and low in the intermediate and deep ones. In the deep layers complex limb and trunk movements could be also elicited. In conclusion, in contrast with carnivores and other mammals, the primate superior colliculus appears to be dominated by the visual modality.

Inferior cortical altitudinal hemianopia: report of a case

A case of bilateral inferior altitudinal hemianopia of cortical origin is reported. Although bilateral altitudinal hemianopias can be caused by more or less symmetrical involvement of visual pathways, it is shown how only three sites of these pathways are likely to be responsible for altitudinal hemianopias in human pathology.

Refsum disease. Clinical and morphological report on a case

An atypical case of Refsum disease is reported together with the peripheral nerve morphological data. The body fluids must be assayed for phytanic acid whenever an atypical chronic peripheral neuropathy is observed.

Response properties and behavioral modulation of "mouth" neurons of the postarcuate cortex (area 6) in macaque monkeys

Single neurons were recorded from the "mouth area" of the postarcuate cortex in macaque monkeys. According to their responses to somatosensory stimuli and their activity during the animal's movements, the neurons were subdivided into three classes: (1) neurons activated only by external stimuli; (2) neurons showing an enhancement of their response when a specific motor act followed the external stimulation; (3) neurons responding reliably to external stimuli only if the stimulation triggered a specific, related motor act. Of the recorded neurons, 50% also responded to visual stimuli.

Neurons with complex visual properties in the superior colliculus of the macaque monkey

Single neurons were recorded from the superficial layers of the superior colliculus of immobilized monkeys (Macaca mulatta and Macaca irus). Two main functional types of neurons were found. The neurons of the first type (Type I neurons) responded well to simple stationary and moving stimuli such as spots, bars or slits of light. The latency of their response was 41 +/- 6 ms. They were not directionally selective and responded to a large range of velocities. The neurons of the second type (Type II neurons) responded very poorly to simple visual stimuli and their activation required real objects or certain two-dimensional patterns. The mean latency of response of these units was 66 +/- 26 ms. Habituation was always present. Type II neurons were located in the lower part of the superficial layers. The characteristics of Type II neurons suggest that in the primate superior colliculus there is a mechanism that allows the recognition of the complexity and the novelty of a stimulus and guides orienting responses to those stimuli that are worth analyzing in detail.

The effect of hemidecortication on the inhibitory interactions in the superior colliculus of the cat

Single neurons were recorded extracellularly from the superficial layers of the superior colliculus (SC) in 21 curarized cats. Four animals were normal unoperated cats, 17 were animals in which all cortical visual areas were ablated on one side from 7 to 69 days before the electrophysiological experiments. After cortical ablation all animals were blind in the visual field contralateral to the ablated side. In both normal and hemianopsic cats the effect of a visual stimulus located very far from the excitatory part of the unit receptive field, on the neuron responses to visual stimuli was studied. The remote stimulus (extra-field stimulus) was a hand moved black spot 10 degrees in diameter. In normal animals the introduction of the extra-field stimulus in the hemifield contralateral or ipsilateral to the recorded SC produced a marked reduction of unit responses to visual stimuli presented in their receptive field. This effect was particularly strong when the extra-field stimuli were introduced in the hemifield contralateral to the recorded side. In the hemianopsic animals the neurons of the SC ipsilateral to the lesion (receptive fields in the behaviorally blind hemifield) responded well to visual stimuli, but were only weakly inhibited by the extra-field stimuli presented in the blind hemifield. The neurons of this colliculus with the exception of those in the upper part of stratum griseum superficiale were normally inhibited by stimuli presented in the normal hemifield. The neurons of the SC contralateral to the lesion responded well to visual stimuli and were normally inhibited by stimuli presented in the normal hemifield; they were virtually not affected by stimuli presented in the blind hemifield. Mechanisms responsible for the abnormal inhibitory interactions between and within colliculi after cortical lesions and the possible behavioral implications of the findings are discussed.

Influence of the presentation of remote visual stimuli on visual responses of cat area 17 and lateral suprasylvian area

Single units were recorded extracellularly from area 17 and lateral suprasylvian area (LSSA) in curarized cats. Visual stimuli, usually a 10 degree black spot, were introduced abruptly in the visual field remote from the discharge area of a neuron's receptive field and moved at a speed of about 30 degrees/sec. The effect of these remote stimuli (S2) on the reponse to a restricted visual stimulus (S1) crossing the discharge area was studied. It was found that most units in area 17 were not affected by the presentation of remote stimuli, the remainder being either slightly facilitated or slightly inhibited. In contrast the LSSA neurons were usually inhibited by the presentation of S2: this effect was strong, was present in all classes of LSSA neurons and was independent of the relative directions of movement of S1 and S2. On the basis of these data and those previously obtained from the superior colliculus it is concluded that the way the extrageniculate centres respond to a stimulus abruptly introduced in the visual field is substantially different from that of the striate cortex. Only in the extrageniculate centres a new stimulus, besides exciting the neurons which correspond to the position of the stimulus in the field, concomitantly decreases the responses of neurons located in positions of the visual field remote from that stimulus. Possible behavioral implications of the findings are discussed.