Glucose Hypometabolism Prompts RAN Translation and Exacerbates C9orf72-related ALS/FTD Phenotypes

The most prevalent genetic cause of both amyotrophic lateral sclerosis and frontotemporal dementia is a (GGGGCC)n nucleotide repeat expansion (NRE) occurring in the first intron of the C9orf72 gene (C9). Brain glucose hypometabolism is consistently observed in C9-NRE carriers, even at pre-symptomatic stages, although its potential role in disease pathogenesis is unknown. Here, we identified alterations in glucose metabolic pathways and ATP levels in the brain of asymptomatic C9-BAC mice. We found that, through activation of the GCN2 kinase, glucose hypometabolism drives the production of dipeptide repeat proteins (DPRs), impairs the survival of C9 patient-derived neurons, and triggers motor dysfunction in C9-BAC mice. We also found that one of the arginine-rich DPRs (PR) can directly contribute to glucose metabolism and metabolic stress. These findings provide a mechanistic link between energy imbalances and C9-ALS/FTD pathogenesis and support a feedforward loop model that opens several opportunities for therapeutic intervention.

C9orf72 poly(PR) mediated neurodegeneration is associated with nucleolar stress

The ALS/FTD-linked intronic hexanucleotide repeat expansion in the C9orf72 gene is translated into dipeptide repeat proteins, among which poly-proline-arginine (PR) displays the most aggressive neurotoxicity in-vitro and in-vivo . PR partitions to the nucleus when expressed in neurons and other cell types. Using drosophila and primary rat cortical neurons as model systems, we show that by lessening the nuclear accumulation of PR, we can drastically reduce its neurotoxicity. PR accumulates in the nucleolus, a site of ribosome biogenesis that regulates the cell stress response. We examined the effect of nucleolar PR accumulation and its impact on nucleolar function and determined that PR caused nucleolar stress and increased levels of the transcription factor p53. Downregulating p53 levels, either genetically or by increasing its degradation, also prevented PR-mediated neurotoxic phenotypes both in in-vitro and in-vivo models. We also investigated whether PR could cause the senescence phenotype in neurons but observed none. Instead, we found induction of apoptosis via caspase-3 activation. In summary, we uncovered the central role of nucleolar dysfunction upon PR expression in the context of C9-ALS/FTD.

TLX, an Orphan Nuclear Receptor With Emerging Roles in Physiology and Disease

TLX (NR2E1), an orphan member of the nuclear receptor superfamily, is a transcription factor that has been described to be generally repressive in nature. It has been implicated in several aspects of physiology and disease. TLX is best known for its ability to regulate the proliferation of neural stem cells and retinal progenitor cells. Dysregulation, overexpression, or loss of TLX expression has been characterized in numerous studies focused on a diverse range of pathological conditions, including abnormal brain development, psychiatric disorders, retinopathies, metabolic disease, and malignant neoplasm. Despite the lack of an identified endogenous ligand, several studies have described putative synthetic and natural TLX ligands, suggesting that this receptor may serve as a therapeutic target. Therefore, this article aims to briefly review what is known about TLX structure and function in normal physiology, and provide an overview of TLX in regard to pathological conditions. Particular emphasis is placed on TLX and cancer, and the potential utility of this receptor as a therapeutic target.

The Cholesterol Metabolite 27HC Increases Secretion of Extracellular Vesicles Which Promote Breast Cancer Progression

Cholesterol has been implicated in the clinical progression of breast cancer, a disease that continues to be the most commonly diagnosed cancer in women. Previous work has identified the cholesterol metabolite 27-hydroxycholesterol (27HC) as a major mediator of the effects of cholesterol on breast tumor growth and progression. 27HC can act as an estrogen receptor (ER) modulator to promote the growth of ERα+ tumors, and as a liver X receptor (LXR) ligand in myeloid immune cells to establish an immune-suppressive program. In fact, the metastatic properties of 27HC require the presence of myeloid cells with neutrophils (polymorphonuclear neutrophils; PMNs) being essential for the increase in lung metastasis in murine models. In an effort to further elucidate the mechanisms by which 27HC alters breast cancer progression, we made the striking finding that 27HC promoted the secretion of extracellular vesicles (EVs), a diverse assortment of membrane bound particles that includes exosomes. The resulting EVs had a size distribution that was skewed slightly larger than EVs generated by treating cells with vehicle. The increase in EV secretion and size was consistent across 3 different subtypes: primary murine PMNs, RAW264.7 monocytic cells, and 4T1 murine mammary cancer cells. Label-free analysis of 27HC-EVs indicated that they had a different metabolite composition to those from vehicle-treated cells. Importantly, 27HC-EVs from primary PMNs promoted tumor growth and metastasis in 2 different syngeneic models, demonstrating the potential role of 27HC-induced EVs in the progression of breast cancer. EVs from PMNs were taken up by cancer cells, macrophages, and PMNs, but not T cells. Since EVs did not alter proliferation of cancer cells, it is likely that their protumor effects are mediated through interactions with myeloid cells. Interestingly, RNA-seq analysis of tumors from 27HC-EV-treated mice do not display significantly altered transcriptomes, suggesting that the effects of 27HC-EVs occur early on in tumor establishment and growth. Future work will be required to elucidate the mechanisms by which 27HC increases EV secretion, and how these EVs promote breast cancer progression. Collectively, however, our data indicate that EV secretion and content can be regulated by a cholesterol metabolite, which may have detrimental effects in terms of disease progression, important findings given the prevalence of both breast cancer and hypercholesterolemia.

Abstract PR006: 27-Hydroxycholesterol acts on myeloid immune cells to induce T cell dysfunction, promoting breast cancer progression

Breast cancer remains one of the leading causes of cancer mortality in the US. Elevated cholesterol is a major risk factor for breast cancer onset and recurrence, while cholesterol-lowering drugs, such as statins, are associated with a good prognosis. Previous work in murine models showed that cholesterol increases breast cancer metastasis, and the pro-metastatic effects of cholesterol were due to its primary metabolite, 27HC. In our prior work, myeloid cells were found to be required for the pro-metastatic effects of 27HC, but their precise contribution remains unclear. Here we report that 27HC impairs T cell expansion and cytotoxic function through its actions on myeloid cells, including macrophages, in an LXR-dependent manner. Many oxysterols and LXR ligands had similar effects on T cell expansion. Moreover, their ability to induce the LXR target gene ABCA1 was associated with their effectiveness in impairing T cell expansion. Interestingly, the enzyme responsible for the synthesis of 27HC, CYP27A1, is highly expressed in myeloid cells, suggesting that 27HC may have important autocrine or paracrine functions in these cells, a hypothesis supported by our finding that breast cancer metastasis was reduced in mice with a myeloid specific knockout of CYP27A1. Pharmacologic inhibition of CYP27A1 reduced metastatic growth and improved the efficacy of checkpoint inhibitor, anti-PD-L1. RNA sequencing of 27HC-treated macrophages and GSEA analysis provide further mechanistic insight, revealing an enrichment of MYC and NOTCH signaling pathways, both of which are documented pathways involved in tumor-associated macrophages. Taken together, our work suggests that targeting the CYP27A1 axis in myeloid cells may present therapeutic benefits and improve the response rate to immune therapies in breast cancer. Delineating the link between LXR and the known mechanisms of tumor-associated macrophages is important to fully understand 27HC-driven cancer metastasis. This work was supported by grants to ERN from the National Cancer Institute of the National Institutes of Health (R01CA234025) and METAvivor.

This abstract is also being presented as PO050.

Citation Format: Liqian Ma, Lawrence Wang, Adam T. Nelson, Chaeyeon Han, Sisi He, Madeline A. Henn, Karan Menon, Joy J. Chen, Amy E. Baek, Anna Vardanyan, Sayyed Hamed Shahoei, Sunghee Park, David J. Shapiro, Som G. Nanjappa, Erik R. Nelson. 27-Hydroxycholesterol acts on myeloid immune cells to induce T cell dysfunction, promoting breast cancer progression [abstract]. In: Abstracts: AACR Virtual Special Conference: Tumor Immunology and Immunotherapy; 2020 Oct 19-20. Philadelphia (PA): AACR; Cancer Immunol Res 2021;9(2 Suppl):Abstract nr PR006.

27-Hydroxycholesterol acts on myeloid immune cells to induce T cell dysfunction, promoting breast cancer progression

Breast cancer remains one of the leading causes of cancer mortality in the US. Elevated cholesterol is a major risk factor for breast cancer onset and recurrence, while cholesterol-lowering drugs, such as statins, are associated with a good prognosis. Previous work in murine models showed that cholesterol increases breast cancer metastasis, and the pro-metastatic effects of cholesterol were due to its primary metabolite, 27-hydroxycholesterol (27HC). In our prior work, myeloid cells were found to be required for the pro-metastatic effects of 27HC, but their precise contribution remains unclear. Here we report that 27HC impairs T cell expansion and cytotoxic function through its actions on myeloid cells, including macrophages, in a Liver X receptor (LXR) dependent manner. Many oxysterols and LXR ligands had similar effects on T cell expansion. Moreover, their ability to induce the LXR target gene ABCA1 was associated with their effectiveness in impairing T cell expansion. Induction of T cell apoptosis was likely one mediator of this impairment. Interestingly, the enzyme responsible for the synthesis of 27HC, CYP27A1, is highly expressed in myeloid cells, suggesting that 27HC may have important autocrine or paracrine functions in these cells, a hypothesis supported by our finding that breast cancer metastasis was reduced in mice with a myeloid specific knockout of CYP27A1. Importantly, pharmacologic inhibition of CYP27A1 reduced metastatic growth and improved the efficacy of checkpoint inhibitor, anti-PD-L1. Taken together, our work suggests that targeting the CYP27A1 axis in myeloid cells may present therapeutic benefits and improve the response rate to immune therapies in breast cancer.

OR05-01 Small Heterodimer Partner Modulates Antigen Presenting Myeloid Cells to Impair Regulatory T Cell Expansion, Promoting Anti-Tumor Immunity in Models of Breast Cancer

Immune checkpoint blockade has had underwhelming responses in breast cancer, in part due to the highly immune suppressive microenvironment. As a result, breast cancer continues to be the second most common cancer-related mortality amongst women, providing strong rationale for the development of new therapeutic approaches. Elevated circulating cholesterol is a poor prognostic, while breast cancer patients taking cholesterol-lowering drugs display increased time to recurrence. We and others have previously demonstrated that cholesterol metabolites mediate these effects by promoting breast cancer growth and metastasis, in part by suppressing the immune system. Therefore, given the demonstrated importance of cholesterol and its metabolites in breast cancer pathophysiology and immunology, we hypothesized that proteins involved in the regulation of cholesterol homeostasis would influence cancer progression. Through informatics analysis of breast tumors, we found that elevated expression of Small Heterodimer Partner (SHP; NR0B2) was a favorable prognostic. Antigen presenting cells such as macrophages and dendritic cells were found to express SHP, and manipulation of SHP altered the expression of genes involved in cross-talk with T cells. Intriguingly, when activated T cells were co-cultured with macrophages overexpressing SHP, there was a decrease in the expansion of regulatory T cells (Tregs) and vice versa in the absence of SHP. Adoptive transfer studies confirmed that loss of SHP resulted in immune suppressive Tregs. We hypothesized that myeloid cell-expressed SHP would promote immune surveillance and tumor clearance. In support of this hypothesis, tumors in the MMTV-PyMT model of mammary cancer grew at an accelerated rate in SHP-knockout mice. Tumors from these mice had significantly more Tregs and fewer effector T cells. Furthermore, orthotopic mammary tumor grafts grew at an increased rate in mice lacking SHP expression in myeloid cells (SHPfl/fl;LysMCre), compared to controls. A small molecule agonist of SHP impaired primary and metastatic tumor growth, and significantly enhanced the efficacy of immune checkpoint blockade in murine models of mammary cancer. Therefore, SHP represents a potential target to decrease suppressive Tregs, thereby allowing for immune-clearance of tumors.

Abstract A93: Macrophage-expressed small heterodimer partner impairs expansion of regulatory T cells and enhances immune checkpoint inhibition

Breast cancer continues to be the second most common cancer-related mortality among women, providing strong rationale for the development of new therapeutic approaches. Cholesterol and its metabolism have been implicated in the progression of breast cancer. Specifically, elevated circulating cholesterol is a poor prognostic, while patients taking cholesterol-lowering drugs such as statins display increased recurrence-free survival time. In addition to cholesterol, various downstream metabolites play direct roles in promoting breast cancer growth and metastasis. Given the demonstrated importance of cholesterol and its metabolites in breast cancer pathophysiology, we hypothesized that proteins involved in the regulation of cholesterol homeostasis would play a role in cancer progression. A bioinformatics-based screen identified small heterodimer partner (SHP; NR0B2) as being associated with an increased time to recurrence. However, manipulation of this negative regulator of cholesterol metabolism within breast cancer cells did not alter proliferation or migration, suggesting that its protective role is likely conveyed through the tumor microenvironment. Macrophages were found to express SHP, and manipulation of SHP within macrophages resulted in altered expression of molecules associated with antigen presentation. Considering the clinical data indicating a protective role for SHP, it was somewhat paradoxical that its loss within macrophages resulted in an increased expansion of T cells. Upon further investigation, we found that this expansion was skewed towards regulatory T cells (Tregs). While immune therapies have revolutionized the treatment of certain cancers, their utility in breast cancer has been limited, especially outside of triple-negative disease. It has been postulated that this may be due to the highly immune-suppressive activities of certain myeloid and T-cell populations. Thus, reducing Treg infiltration or activity likely represents a rational way to enhance immune therapies. In this regard, SHP-knockout mice bred with the MMTV-PyMT model of mammary cancer displayed significantly enhanced tumor growth compared to SHP-replete mice. Likewise, orthotopic mammary tumor grafts grew at an increased rate in mice where SHP was selectively knocked out in cells of the myeloid lineage (SHPfl/fl;LysMCre), compared to controls. Importantly, treatment with a small-molecule agonist of SHP significantly enhanced the efficacy of anti-PD-L1 therapy in blocking the growth of an orthotopically grafted tumor, as well as in a model of metastatic mammary cancer. Collectively, our data highlight SHP as a modulator of Tregs, a cell population that has thus far been therapeutically intractable. By limiting Treg expansion and thus facilitating an anticancer immune response, SHP may represent a unique way to enhance the efficacy of immune checkpoint blockade. Funding: DOD BCRP BC171214 and NCI R01CA234025 (ERN), Lipstic Labex ANR-11-LABX-0021 (LA), Chateaubriand Fellowship (SHS).

Citation Format: Sayyed Hamed Shahoei, Adam T. Nelson, Madeline A. Henn, Ashley E. Mathews, Joy J. Chen, Varsha Vembar, Liqian Ma, Lionel Apetoh, Erik R. Nelson. Macrophage-expressed small heterodimer partner impairs expansion of regulatory T cells and enhances immune checkpoint inhibition [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2019 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(3 Suppl):Abstract nr A93.

Abstract P6-05-01: The small heterodimer partner in macrophages reduces expansion of regulatory T cells and enhances immune checkpoint inhibition in breast cancer

It has become clear that cholesterol metabolism and homeostasis play significant roles in the progression of breast cancer. Specifically, elevated circulating cholesterol is a poor prognostic, while patients taking cholesterol-lowering drugs such as statins display increased recurrence-free survival time. Preclinical and clinical work has established that in addition to cholesterol, various downstream metabolites play direct roles in promoting breast cancer growth and metastasis. Given the demonstrated importance of cholesterol and its metabolites in breast cancer pathophysiology, we hypothesized that proteins involved in the regulation of cholesterol homeostasis would play a role in cancer progression. Therefore, we performed an informatics screen to identify those regulatory proteins associated with breast cancer progression. We focused on nuclear receptors due to their well-defined ligand-binding pocket and thus their proclivity to drug intervention. Our screen revealed that increased expression of Small Heterodimer Partner (SHP; NR0B2) was associated with an increased time to recurrence. However, manipulation of SHP within breast cancer cells did not alter proliferation or migration, suggesting that its protective role is likely conveyed through the tumor microenvironment. Macrophages were found to express SHP, and manipulation of SHP within macrophages resulted in altered expression of molecules associated with antigen presentation. Considering the clinical data indicating a protective role for SHP, it was somewhat paradoxical that its loss within macrophages resulted in an increased expansion of T cells. Upon further investigation, we found that this expansion was skewed towards regulatory T cells (Tregs). On the other hand, overexpression of SHP resulted in decreased expansion of Tregs. The immune-suppressive activity of the resulting Tregs was confirmed in subsequent assays. While immune therapies have revolutionized the treatment of certain cancers, their utility in breast cancer has been limited, especially outside of triple-negative disease. It has been speculated that this may be due to the highly immune-suppressive activities of certain myeloid and T cell populations. Thus, reducing Treg infiltration or activity likely represents a rational way to enhance immune therapies. In this regard, SHP-knockout mice bred with the MMTV-PyMT model of mammary cancer displayed significantly enhanced tumor growth compared to SHP-replete mice. Likewise, orthotopic mammary tumor grafts grew at an increased rate in mice where SHP was selectively knocked out in cells of the myeloid lineage (SHPfl/fl;LysMCre), compared to controls. Importantly, treatment with a small molecule agonist of SHP significantly enhanced the efficacy of anti-PD-L1 therapy in blocking the growth of an orthotopically grafted tumor, as well as in a model of metastatic mammary cancer. Collectively, our data strongly support a role for SHP in reducing the progression of breast cancer by limiting Treg expansion, thereby facilitating an anti-cancer immune response. As this nuclear receptor is amenable to small molecule intervention, SHP may represent a unique way to enhance the efficacy of immune checkpoint blockade.

This study was funded in part by awards to ERN from the DOD BCRP (BC171214) and NCI (R01CA234025), to LA from the French National Research Agency Lipstic Labex (ANR-11-LABX-0021), and a STEM Chateaubriand Fellowship to SHS from the Embassy of France in the United States.

Citation Format: Erik R. Nelson, Sayyed Hamed Shahoei, Adam T Nelson, Madeline A Henn, Ashley E Mathews, Joy J Chen, Varsha Vembar, Liqian Ma, Lionel Apetoh. The small heterodimer partner in macrophages reduces expansion of regulatory T cells and enhances immune checkpoint inhibition in breast cancer [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 P6-05-01.

Host CYP27A1 expression is essential for ovarian cancer progression

There is an urgent need for more effective strategies to treat ovarian cancer. Elevated cholesterol levels are associated with a decreased progression-free survival time (PFS) while statins are protective. 27-Hydroxycholesterol (27HC), a primary metabolite of cholesterol, has been shown to modulate the activities of the estrogen receptors (ERs) and liver x receptors (LXRs) providing a potential mechanistic link between cholesterol and ovarian cancer progression. We found that high expression of CYP27A1, the enzyme responsible for the synthesis of 27HC, was associated with decreased PFS, while high expression of CYP7B1, responsible for 27HC catabolism, was associated with increased PFS. However, 27HC decreased the cellular proliferation of various ovarian cancer cell lines in an LXR-dependent manner. Intriguingly, ID8 grafts were unable to effectively establish in CYP27A1-/- mice, indicating involvement of the host environment. Tumors from mice treated with 27HC had altered myeloid cell composition, and cells from the marrow stem cell lineage were found to be responsible for the effects in CYP27A1-/- mice. While inhibition of CYP27A1 or immune checkpoint did not significantly alter tumor size, their combination did, thereby highlighting this axis as a therapeutic target.

Sagittal plane analysis of head, neck, and trunk kinematics and electromyographic activity during locomotion

STUDY DESIGN

Descriptive study examining kinematic and electromyographic (EMG) patterns of the upper body during walking.

OBJECTIVE

To examine trunk, neck, and head movements to determine a mechanism for upper body stabilization during walking.

BACKGROUND

Dynamic balance of the upper body during walking provides a stable base for function of sensory systems. Prior investigations of upper body motion during walking were limited to examination of isolated segments, or examination of the upper body as a single unit. In our study, the upper body is examined as 3 segments: the trunk, neck, and head.

METHODS AND MEASURES

Sagittal plane walking patterns were examined in 8 unimpaired young adults. Markers placed on the trunk, neck, and head segments were recorded on videotape. Angles were calculated with respect to an external horizontal reference to determine segment position relative to space. EMG measures were obtained from erector spinae, rectus abdominus, semispinalis capitis, and sternocleidomastoid muscles.

RESULTS

Results showed dynamic stability was accomplished through maintenance of a posture where the trunk was flexed, the neck was extended and the head was flexed. The trunk segment demonstrated greatest stability with the neck being the least stable of the 3 segments. Movements of upper body segments showed a tendency for the head and neck to move opposite to the trunk. EMG data demonstrated erector spinae muscle activity occurring near heel contact of each limb followed by trunk extension. The remaining muscles exhibited variable patterns of activity.

CONCLUSIONS

These data indicate that movements of the upper body help to maintain a posture that promotes stability of these segments during walking. The trunk was the most stable of the three segments thereby, providing a stable platform for head and neck movement. Erector spinae muscle activity contributed to upper body movements by extending the trunk to maintain balance at heel contact. These results provide a basis for studying changes in dynamic stability that occur with age.

Lymphoid markers, activation markers, and adhesion molecules in cutaneous biopsy specimens from HIV+ patients with disease progression. The Military Medical Consortium for the Advancement of Retroviral Research

BACKGROUND

One important factor in understanding the pathogenesis of human immune deficiency virus (HIV) disease is documenting the patterns of immune dysregulation present in HIV-positive patients. The cells which home to skin are mainly certain subsets of T cells and, as opposed to the peripheral blood, where circulating factors may inhibit terminal phenotypic differentiation, the cutaneous environment potentiates differentiation during cutaneous eruptions.

OBJECTIVE

The authors' aim was to characterize the inflammatory dermatoses in biopsy specimens from HIV-positive patients with immunohistochemical stains for lymphoid markers, activation markers, and adhesion molecules and to determine if there was any correlation with the type of dermatosis and the HIV-disease stage.

METHODS

Lymphoid and activation markers as well as adhesion molecules were studied on cutaneous biopsy specimens from 96 inflammatory dermatoses in HIV-positive patients. The dermatoses included psoriasiform dermatoses with and without a lichenoid component, perivascular lymphoid dermatoses, perivascular and periadnexal inflammatory dermatoses, spongiotic dermatoses, granulomatous dermatoses, and neutrophilic dermatoses with and without vasculitis.

RESULTS

Although there was a decrease in CD4/CD8 ratios in the cutaneous inflammatory dermatoses with progression of the disease, the ratios of CD4/CD8 cells were far higher than those in the peripheral blood. There were also increasing numbers of CD23+ cells and increased E-Selectin expression on endothelial cells from the early stages of disease, with no consistent pattern of ICAM-1 expression on epithelial cells with disease progression.

CONCLUSIONS

The expression of lymphoid markers, activation markers, and adhesion molecules in the skin with progression of HIV disease, is consistent with a T helper (Th)1 to Th0/Th2 cytokine pattern of immune dysregulation. This cytokine pattern may be modified by the cytopathic effects of HIV on lymphoid and dendritic populations and by effects of other concurrent infections. Significant numbers of CD4+ T cells in skin infiltrates, with low peripheral CD4 T-cell counts, suggest that the cutaneous T-cell populations may be distinctive.

Percentage of reversibly and irreversibly sickled cells are altered by the method of blood drawing and storage conditions

We previously reported that the percentage of reversibly and irreversibly sickled cells (RSC and ISC, respectively) in the blood of patients with sickle cell disease is strongly influenced by the method of blood drawing (PNAS 91:12589, 1994). We now document the effect of blood storage conditions on the percentage of RSC and ISC. The percentage of RSC was lowest when blood was stored at 0 degree C, while the percentage of RSC was highest in specimens kept at 37 degrees C. At room temperature, the percentage of RSC increased slightly over 8 hours. The percentage of ISC was also temperature dependent and was reduced significantly upon cooling. Our results showed that many ISC reverted to a discoidal shape after 3 hrs of cooling after treatment of blood with oxygen or carbon monoxide. Since no Hb S polymers were detected in ISC treated with oxygen or carbon monoxide, the time required for shape restoration may be attributed to the membrane. We measured ISC levels of 10 patients with consideration of storage temperature and compared the values with those determined by the conventional method and also with those published previously.

Mitogen-activated lymphocytes of normals and glioma patients produce factors with anti-glioblastoma activity in vitro

Human glioblastoma cell lines showed profound suppression of both DNA and RNA synthesis when exposed to supernatants (SNs) of mitogen-activated blood mononuclear cells. Cloning efficiency of these glioma cells also decreased 10- to 500-fold. In monolayer cultures, growth inhibition was evident within 12 h of adding SN and peaked at 24 h. A decrease in absolute cell number was evident by 72 h. The inhibitory effect of SNs, however, was not permanent as more cells entered S-phase when SN-treated cultures were refed with fresh medium (without SN). The factor(s) responsible for this inhibitory activity was a product of lymphocytes and was produced in comparable amounts by cells of normal blood donors and patients with glioma. The compromised immunological status of glioblastoma patients did not influence their capacity to produce cytostatic lymphokines.

Residual anterior pituitary function following transsphenoidal resection of pituitary macroadenomas

A series of 84 patients with pituitary adenomas greater than 1 cm in diameter is presented. Full preoperative and postoperative endocrine evaluations were carried out, and the effects of transsphenoidal surgery on remaining anterior pituitary function were analyzed. Of the patients who had normal anterior pituitary function before surgery, 78% retained normal function after surgery. Thirty-three percent of those patients with pituitary deficits who did not have panhypopituitarism before surgery had improved function after surgery; 33% had worsened function after surgery. None of the patients with panhypopituitarism before surgery regained function after surgery. Transsphenoidal surgery carries an acceptable risk for sacrificing anterior pituitary function, but the risk is greater in patients with larger tumors and preoperatively compromised pituitary function.