Vei Mah

Global Levels of Histone Modifications Predict Prognosis in Different Cancers

Cancer cells exhibit alterations in histone modification patterns at individual genes and globally at the level of single nuclei in individual cells. We demonstrated previously that lower global/cellular levels of histone H3 lysine 4 dimethylation (H3K4me2) and H3K18 acetylation (ac) predict a higher risk of prostate cancer recurrence. Here we show that the cellular levels of both H3K4me2 and H3K18ac also predict clinical outcome in both lung and kidney cancer patients, with lower levels predicting significantly poorer survival probabilities in both cancer groups. We also show that lower cellular levels of H3K9me2, a modification associated with both gene activity and repression, is also prognostic of poorer outcome for individuals with either prostate or kidney cancers. The predictive power of these histone modifications was independent of tissue-specific clinicopathological variables, the proliferation marker Ki-67, or a p53 tumor suppressor mutation. Chromatin immunoprecipitation experiments indicated that the lower cellular levels of histone modifications in more aggressive cancer cell lines correlated with lower levels of modifications at DNA repetitive elements but not with gene promoters across the genome. Our results suggest that lower global levels of histone modifications are predictive of a more aggressive cancer phenotype, revealing a surprising commonality in prognostic epigenetic patterns of adenocarcinomas of different tissue origins.

Aromatase Expression Predicts Survival in Women with Early-Stage Non-Small Cell Lung Cancer

Estrogen signaling is critical in the progression of tumors that bear estrogen receptors. In most patients with breast cancer, inhibitors that block interactions of estrogen with its receptors or suppress the production of endogenous estrogens are important interventions in the clinic. Recent evidence now suggests that estrogen also contributes to the pathogenesis of non-small cell lung cancer (NSCLC). We used a human lung cancer xenograph model system to analyze the effect of aromatase or estradiol on tumor growth. We further examined the level of protein expression of aromatase in 422 patients with NSCLC using a high-density tissue microarray. Results were confirmed and validated on an independent patient cohort (n = 337). Lower levels of aromatase predicted a greater chance of survival in women 65 years and older. Within this population, the prognostic value of aromatase was greatest in earlier stage lung cancer (stage I/II). In addition, for women with no history of smoking, lower aromatase levels were a strong predictor of survival. Our findings implicate aromatase as an early-stage predictor of survival in some women with NSCLC. We predict that women whose lung cancers have higher levels of aromatase might be good candidates for targeted treatment with aromatase inhibitors.

Neuropathologic findings after bone marrow transplantation: An autopsy study

Clinicopathologic records and neuropathologic tissues of 109 patients who underwent necropsy after treatment with bone marrow transplantation (BMT) were examined. Underlying disorders included leukemia (70), aplastic anemia (25), solid tumors (7), lymphoma (5), Hodgkins disease (1) and Wiskott-Aldrich syndrome (1). There were 34 females and 75 males, ranging in age from 2 to 56 years. Survival after transplantation averaged 3.6 months. The most common findings were cerebrovascular lesions (29), including hematomas, hemorrhagic necrosis, and infarcts. Central nervous system infections comprised the next most common finding, including 10 fungal and four bacterial infections. A recurrence of underlying malignancy for which transplant had been performed occurred in five patients. Leukoencephalopathy of varying severity was found in eight patients, half of whom had received intrathecal chemotherapy and/or cranial radiation. Patients with systemic graft-versus-host disease had a variety of nonspecific neuropathologic findings in the nervous system; however, nearly half (44%) showed no detectable changes. Other nonspecific alterations included hypoxic/ischemic changes, vascular siderocalcinosis, and neuroaxonal spheroids (associated with hemorrhage or necrosis). These findings provide a guide as to likely causes of a neurologic syndrome in a patient who has undergone BMT, and can be compared with neuropathologic findings in other forms of immunosuppression.

Higher Levels of GATA3 Predict Better Survival in Women with Breast Cancer

The GATA family members are zinc finger transcription factors involved in cell differentiation and proliferation. GATA3 in particular is necessary for mammary gland maturation, and its loss has been implicated in breast cancer development. Our goal was to validate the ability of GATA3 expression to predict survival in breast cancer patients. Protein expression of GATA3 was analyzed on a high-density tissue microarray consisting of 242 cases of breast cancer. We associated GATA3 expression with patient outcomes and clinicopathologic variables. Expression of GATA3 was significantly increased in breast cancer, in situ lesions, and hyperplastic tissue compared with normal breast tissue. GATA3 expression decreased with increasing tumor grade. Low GATA3 expression was a significant predictor of disease-related death in all patients, as well as in subgroups of estrogen receptor-positive or low-grade patients. In addition, low GATA3 expression correlated with increased tumor size and estrogen and progesterone receptor negativity. GATA3 is an important predictor of disease outcome in breast cancer patients. This finding has been validated in a diverse set of populations. Thus, GATA3 expression has utility as a prognostic indicator in breast cancer.

Snail Promotes CXCR2 Ligand–Dependent Tumor Progression in Non–Small Cell Lung Carcinoma

Purpose: As a transcriptional repressor of E-cadherin, Snail has predominantly been associated with epithelial-mesenchymal transition, invasion, and metastasis. However, other important Snail-dependent malignant phenotypes have not been fully explored. Here, we investigate the contributions of Snail to the progression of nonsmall cell lung cancer (NSCLC). Experimental Design: Immunohistochemistry was done to quantify and localize Snail in human lung cancer tissues, and tissue microarray analysis was used to correlate these findings with survival. NSCLC cell lines gene-modified to stably overexpress Snail were evaluated in vivo in two severe combined immunodeficiency murine tumor models. Differential gene expression between Snail-overexpressing and control cell lines was evaluated using gene expression microarray analysis. Results: Snail is upregulated in human NSCLC tissue, and high levels of Snail expression correlate with decreased survival (P < 0.026). In a heterotopic model, mice bearing Snail-overexpressing tumors developed increased primary tumor burden (P = 0.008). In an orthotopic model, mice bearing Snail-overexpressing tumors also showed a trend toward increased metastases. In addition, Snail overexpression led to increased angiogenesis in primary tumors as measured by MECA-32 (P < 0.05) positivity and CXCL8 (P = 0.002) and CXCL5 (P = 0.0003) concentrations in tumor homogenates. Demonstrating the importance of these proangiogenic chemokines, the Snail-mediated increase in tumor burden was abrogated with CXCR2 blockade. Gene expression analysis also revealed Snail-associated differential gene expression with the potential to affect angiogenesis and diverse aspects of lung cancer progression. Conclusion: Snail upregulation plays a role in human NSCLC by promoting tumor progression mediated by CXCR2 ligands. (Clin Cancer Res 2009;15(22):68209)

Presence of a putative tumor-initiating progenitor cell population predicts poor prognosis in smokers with non-small cell lung cancer.

Smoking is the most important known risk factor for the development of lung cancer. Tobacco exposure results in chronic inflammation, tissue injury, and repair. A recent hypothesis argues for a stem/progenitor cell involved in airway epithelial repair that may be a tumor-initiating cell in lung cancer and which may be associated with recurrence and metastasis. We used immunostaining, quantitative real-time PCR, Western blots, and lung cancer tissue microarrays to identify subpopulations of airway epithelial stem/progenitor cells under steady-state conditions, normal repair, aberrant repair with premalignant lesions and lung cancer, and their correlation with injury and prognosis. We identified a population of keratin 14 (K14)-expressing progenitor epithelial cells that was involved in repair after injury. Dysregulated repair resulted in the persistence of K14+ cells in the airway epithelium in potentially premalignant lesions. The presence of K14+ progenitor airway epithelial cells in NSCLC predicted a poor prognosis, and this predictive value was strongest in smokers, in which it also correlated with metastasis. This suggests that reparative K14+ progenitor cells may be tumor-initiating cells in this subgroup of smokers with NSCLC.

Expression levels of estrogen receptor beta in conjunction with aromatase predict survival in non-small cell lung cancer

Estrogen signaling pathways may play a significant role in the pathogenesis of non-small cell lung cancers (NSCLC) as evidenced by the expression of aromatase and estrogen receptors (ERα and ERβ) in many of these tumors. Here we examine whether ERα and ERβ levels in conjunction with aromatase define patient groups with respect to survival outcomes and possible treatment regimens. Immunohistochemistry was performed on a high-density tissue microarray with resulting data and clinical information available for 377 patients. Patients were subdivided by gender, age and tumor histology, and survival data was determined using the Cox proportional hazards model and Kaplan-Meier curves. Neither ERα nor ERβ alone was predictor of survival in NSCLC. However, when coupled with aromatase expression, higher ERβ levels predicted worse survival in patients whose tumors expressed higher levels of aromatase. Although this finding was present in patients of both genders, it was especially pronounced in women ≥ 65 years old, where higher expression of both ERβ and aromatase indicated a markedly worse survival rate than that determined by aromatase alone. Expression of ERβ together with aromatase has predictive value for survival in different gender and age subgroups of NSCLC patients. This predictive value is stronger than each individual marker alone. Our results suggest treatment with aromatase inhibitors alone or combined with estrogen receptor modulators may be of benefit in some subpopulations of these patients.

MCT1 Modulates Cancer Cell Pyruvate Export and Growth of Tumors that Co-express MCT1 and MCT4

Monocarboxylate transporter 1 (MCT1) inhibition is thought to block tumor growth through disruption of lactate transport and glycolysis. Here, we show MCT1 inhibition impairs proliferation of glycolytic breast cancer cells co-expressing MCT1 and MCT4 via disruption of pyruvate rather than lactate export. MCT1 expression is elevated in glycolytic breast tumors, and high MCT1 expression predicts poor prognosis in breast and lung cancer patients. Acute MCT1 inhibition reduces pyruvate export but does not consistently alter lactate transport or glycolytic flux in breast cancer cells that co-express MCT1 and MCT4. Despite the lack of glycolysis impairment, MCT1 loss-of-function decreases breast cancer cell proliferation and blocks growth of mammary fat pad xenograft tumors. Our data suggest MCT1 expression is elevated in glycolytic cancers to promote pyruvate export that when inhibited, enhances oxidative metabolism and reduces proliferation. This study presents an alternative molecular consequence of MCT1 inhibitors, further supporting their use as anti-cancer therapeutics.

Progesterone and estrogen receptor expression and activity in human non-small cell lung cancer.

Lung cancer is the most common cause of cancer mortality in male and female patients in the US. Although it is clear that tobacco smoking is a major cause of lung cancer, about half of all women with lung cancer worldwide are never-smokers. Despite a declining smoking population, the incidence of non-small cell lung cancer (NSCLC), the predominant form of lung cancer, has reached epidemic proportions particularly in women. Emerging data suggest that factors other than tobacco, namely endogenous and exogenous female sex hormones, have a role in stimulating NSCLC progression. Aromatase, a key enzyme for estrogen biosynthesis, is expressed in NSCLC. Clinical data show that women with high levels of tumor aromatase (and high intratumoral estrogen) have worse survival than those with low aromatase. The present and previous studies also reveal significant expression and activity of estrogen receptors (ERα, ERβ) in both extranuclear and nuclear sites in most NSCLC. We now report further on the expression of progesterone receptor (PR) transcripts and protein in NSCLC. PR transcripts were significantly lower in cancerous as compared to non-malignant tissue. Using immunohistochemistry, expression of PR was observed in the nucleus and/or extranuclear compartments in the majority of human tumor specimens examined. Combinations of estrogen and progestins administered in vitro cooperate in promoting tumor secretion of vascular endothelial growth factor and, consequently, support tumor-associated angiogenesis. Further, dual treatment with estradiol and progestin increased the numbers of putative tumor stem/progenitor cells. Thus, ER- and/or PR-targeted therapies may offer new approaches to manage NSCLC.

Differential expression of anterior gradient gene AGR2 in prostate cancer

BackgroundThe protein AGR2 is a putative member of the protein disulfide isomerase family and was first identified as a homolog of the Xenopus laevis gene XAG-2. AGR2 has been implicated in a number of human cancers. In particular, AGR2 has previously been found to be one of several genes that encode secreted proteins showing increased expression in prostate cancer cells compared to normal prostatic epithelium.MethodsGene expression levels of AGR2 were examined in prostate cancer cells by microarray analysis. We further examined the relationship of AGR2 protein expression to histopathology and prostate cancer outcome on a population basis using tissue microarray technology.ResultsAt the RNA and protein level, there was an increase in AGR2 expression in adenocarcinoma of the prostate compared to morphologically normal prostatic glandular epithelium. Using a tissue microarray, this enhanced AGR2 expression was seen as early as premalignant PIN lesions. Interestingly, within adenocarcinoma samples, there was a slight trend toward lower levels of AGR2 with increasing Gleason score. Consistent with this, relatively lower levels of AGR2 were highly predictive of disease recurrence in patients who had originally presented with high-stage primary prostate cancer (P = 0.009).ConclusionsWe have shown for the first time that despite an increase in AGR2 expression in prostate cancer compared to non-malignant cells, relatively lower levels of AGR2 are highly predictive of disease recurrence following radical prostatectomy.