Invasive Adenocarcinoma Lesions Research Articles

Progressive changes in the protein expression profile of alveolar septa in early-stage lung adenocarcinoma.

Adenocarcinomas show a stepwise progression from atypical adenomatous hyperplasia (AAH) through adenocarcinoma in situ (AIS) to invasive adenocarcinoma (IA). Immunoglobulin superfamily containing leucine-rich repeat (ISLR) is a marker of tumor-restraining cancer-associated fibroblasts (CAFs), which are distinct from conventional, strongly α-smooth muscle actin (αSMA)-positive CAFs. Fibroblastactivation protein (FAP) has been focused on as a potential therapeutic and diagnostic target of CAFs. We investigated the changes in protein expression during adenocarcinoma progression in the pre-existing alveolar septa by assessing ISLR, αSMA, and FAP expression in normallung, AAH, AIS, and IA. Fourteen AAH, seventeen AIS, and twenty IA lesions were identified and randomly sampled. Immunohistochemical analysis was performed to evaluate cancer-associated changes and FAP expression in the pre-existing alveolar structures. Normal alveolar septa expressed ISLR. The ISLR level in the alveolar septa decreased in AAH and AIS tissues when compared with that in normal lung tissue. The αSMA-positive area gradually increased from the adjacent lung tissue (13.3% ± 15%) to AIS (87.7% ± 14%), through AAH (70.2% ± 21%). Moreover, the FAP-positive area gradually increased from AAH (1.69% ± 1.4%) to IA (11.8% ± 7.1%), through AIS (6.11% ± 5.3%). Protein expression changes are a feature of CAFs in the pre-existing alveolar septa that begin in AAH. These changes gradually progressed from AAH to IA through AIS. FAP-positive fibroblasts may contribute to tumor stroma formation in early-stage lung adenocarcinoma, and this could influence the development of therapeutic strategies targeting FAP-positive CAFs for disrupting extracellular matrix formation.

Predicting the pathological invasiveness of early lung adenocarcinoma prior to surgery using Deauville criteria: reliability and validity

PurposeThis retrospective study aimed to investigate the validity and reliability of FDG-PET/CT visual assessment using Deauville criteria to predict pathological invasiveness of early lung adenocarcinoma prior to surgery.Materials and methodsBetween April 2020 and January 2022, 51 patients who underwent surgery for pathological stage 0/I lung adenocarcinoma were enrolled. The pulmonary lesions were divided into two groups according to pathological invasiveness: less invasive (including adenocarcinoma in situ and minimally invasive adenocarcinoma and invasive adenocarcinoma. We compared CT size (total and solid size), SUVmax, and Deauville score between the two groups. Furthermore, we investigated inter-rater and intra-rater agreements regarding the Deauville score. Receiver operating characteristic (ROC) curve analysis was performed to identify the diagnostic performance of each method.ResultsBased on pathologic diagnoses, 51 lesions in the 51 patients were divided into 6 less invasive and 45 invasive adenocarcinoma lesions. According to quadratic-weighted Kappa statistics, inter-rater (k = 0.93) and intra-rater (k = 0.97) agreements among all five components of the Deauville score indicated high agreement. There was a statistically significant difference in CT solid size, SUVmax, and Deauville score between the two groups. There were no significant differences between CT solid size and FDG-PET/CT assessments (AUC = 0.93 for Deauville score and SUVmax, AUC = 0.84 for CT solid size).ConclusionFDG-PET/CT visual assessment using the Deauville score could assist in deciding upon minimally invasive surgery for early lung adenocarcinoma.

Radiomics-based analysis of CT imaging for the preoperative prediction of invasiveness in pure ground-glass nodule lung adenocarcinomas

ObjectiveThe purpose of the study is to investigate the performance of radiomics-based analysis in prediction of pure ground-glass nodule (pGGN) lung adenocarcinomas invasiveness using thin-section computed tomography images.MethodsA total of 382 patients surgically resected single pGGN and pathologically confirmed were enrolled in the retrospective study. The pGGN cases were divided into two groups: the noninvasive group and the invasive adenocarcinoma (IAC) group. 330 patients were randomly assigned to the training and testing cohorts with a ratio of 7:3 (245 noninvasive lesions, 85 IAC lesions), while 52 patients (30 noninvasive lesions, 22 IAC lesions) were assigned to the external validation cohort. A model, radiomics model, and combined clinical-radiographic-radiomic model were built using the LASSO and multivariate backward stepwise regression analysis on the basis of the selected and radiomics features. The area under the curve (AUC) and decision curve analysis (DCA) were used to evaluate and compare the model performance for invasiveness discrimination among the three cohorts.ResultsThree clinical-radiographic features (including age, gender and the mean CT value) and three radiomics features were selected for model building. The combined model and radiomics model performed better than the clinical-radiographic model. The AUCs of the combined model in the training, testing, and validation cohorts were 0.856, 0.859, and 0.765, respectively. The DCA demonstrated the radiomics signatures incorporating clinical-radiographic feature was clinically useful in predicting pGGN invasiveness.ConclusionsThe proposed radiomics-based analysis incorporating the clinical-radiographic feature could accurately predict pGGN invasiveness, providing a noninvasive biomarker for the individualized and precise medical treatment of patients.

Clinical value of a differentiation prediction model for invasive lung adenocarcinoma

Objective: To investigate the value of predicting the degree of differentiation of pulmonary invasive adenocarcinoma (IAC) based on CT image radiomics model and the expression difference of immunohistochemical factors between different degrees of differentiation of lesions. Methods: The clinicopathological data of patients with pulmonary IAC confirmed by surgical pathology in the Affiliated Huai'an First People's Hospital to Nanjing Medical University from December 2017 to September 2018 were collected. High-throughput feature acquisition was performed for all outlined regions of interest, and prediction models were constructed after dimensionality reduction by the minimum absolute shrinkage operator. Receiver operating characteristic curve was used to assess the predictive efficacy of clinical characteristic model, radiomics model and individualized prediction model combined with both to identify the degree of pulmonary IAC differentiation, and immunohistochemical expressions of Ki-67, NapsinA and TTF-1 were compared between groups with different degrees of IAC differentiation using rank sum test. Results: A total of 396 high-throughput features were extracted from all IAC lesions, and 10 features with high generalization ability and correlation with the degree of IAC differentiation were screened. The mean radiomics score of poorly differentiated IAC in the training group (1.206) was higher than that of patients with high and medium differentiation (0.969, P=0.001), and the mean radiomics score of poorly differentiated IAC in the test group (1.545) was higher than that of patients with high and medium differentiation (-0.815, P<0.001). The differences in gender (P<0.001), pleural stretch sign (P=0.005), and burr sign (P=0.033) were statistically significant between patients in the well and poorly differentiated IAC groups. Multifactorial logistic regression analysis showed that gender and pleural stretch sign were related to the degree of IAC differentiation (P<0.05). The clinical feature model consisted of age, gender, pleural stretch sign, burr sign, tumor vessel sign, and vacuolar sign, and the individualized prediction model consisted of gender, pleural stretch sign, and radiomic score, and was represented by a nomogram. The Akaike information standard values of the radiomics model, clinical feature model and individualized prediction model were 54.756, 82.214 and 53.282, respectively. The individualized prediction model was most effective in identifying the degree of differentiation of pulmonary IAC, and the area under the curves (AUC) of the individualized prediction model in the training group and the test group were 0.92 (95% CI: 0.86-0.99) and 0.88 (95% CI: 0.74-1.00, respectively). The AUCs of the radiomics group model for predicting the degree of differentiation of pulmonary IAC in the training group and the test group were 0.91 (95% CI: 0.83-0.98) and 0.87 (95% CI: 0.72-1.00), respectively. The AUCs of the clinical characteristics model for predicting the degree of differentiation of pulmonary IACs in the training and test groups were 0.75 (95% CI: 0.63-0.86) and 0.76 (95% CI: 0.59-0.94), respectively. The expression level of Ki-67 in poorly differentiated IAC was higher than that in well-differentiated IAC (P<0.001). The expression levels of NapsinA, TTF-1 in poorly differentiated IAC were higher than those in well-differentiated IAC (P<0.05). Conclusions: Individualized prediction model consisted of gender, pleural stretch sign and radiomics score can discriminate the differentiation degree of IAC with the best performance in comparison with clinical feature model and radiomics model. Ki-67, NapsinA and TTF-1 express differently in different degrees of differentiation of IAC.

Pulmonary Functional Imaging for Lung Adenocarcinoma: Combined MRI Assessment Based on IVIM-DWI and OE-UTE-MRI.

PurposeThe goal of current study was to introduce noninvasive and reproducible MRI methods for in vivo functional assessment of lung adenocarcinoma (LUAD).MethodsForty-four patients with pathologically confirmed LUAD were included in this study. All the lesions were classified as adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA), or invasive adenocarcinoma (IA). The IA lesions were further divided into five subtype patterns, including acinar, lepidic, papillary, micropapillary and solid. Tumors were grouped depending on predominant subtype: low grade (AIS, MIA or lepidic predominant), intermediate grade (papillary or acinar predominant) and high grade (micropapillary, or solid predominant). Spirometry was performed according to American Thoracic Society guidelines. For each patient, Intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI) analysis and oxygen-enhanced MRI (OE-MRI) analysis were performed. Spearman’s test was used to assess the relationship between a) whole lung mean percent signal enhancement (PSE) and pulmonary function tests (PFTs) parameters; b) IVIM-derived parameters and PFTs parameters; c) tumor mean PSE and IVIM-derived parameters. Kruskal -Wallis tests were applied to test the difference of tumor mean PSE and IVIM-derived parameters between different histological tumor grades. Receiver operating characteristics (ROC) analysis was used to evaluate the diagnostic performance.ResultsWhole lung mean PSE was significantly positively correlated with PFTs parameters (r = 0.40 ~ 0.44, P < 0.05). f value derived from IVIM-DWI was significantly negatively correlated with PFTs parameters (r = -0.38 ~ -0.47, P < 0.05). Both tumor mean PSE (P = 0.030 < 0.05) and f (P = 0.022 < 0.05) could differentiate different histological grades. f was negatively correlated with tumor mean PSE (r = -0.61, P < 0.001). For the diagnostic performance, the combination of tumor mean PSE and f outperformed than using tumor mean PSE or f alone in both sensitivity and area under the ROC curve.ConclusionsThe combined measurement of OE-MRI and IVIM-DWI may serve as a promising method for the noninvasive and non-radiation evaluation of pulmonary function. Quantitative analyses achieved by OE-MRI and IVIM-DWI offer an approach of the classification of LUAD subtypes.

Whole-Lesion Computed Tomography-Based Entropy Parameters for the Differentiation of Minimally Invasive and Invasive Adenocarcinomas Appearing as Pulmonary Subsolid Nodules.

The aim of this study was to investigate the differentiation of computed tomography (CT)-based entropy parameters between minimally invasive adenocarcinoma (MIA) and invasive adenocarcinoma (IAC) lesions appearing as pulmonary subsolid nodules (SSNs). This study was approved by the institutional review board in our hospital. From July 2015 to November 2018, 186 consecutive patients with solitary peripheral pulmonary SSNs that were pathologically confirmed as pulmonary adenocarcinomas (74 MIA and 112 IAC lesions) were included and subdivided into the training data set and the validation data set. Chest CT scans without contrast enhancement were performed in all patients preoperatively. The subjective CT features of the SSNs were reviewed and compared between the MIA and IAC groups. Each SSN was semisegmented with our in-house software, and entropy-related parameters were quantitatively extracted using another in-house software developed in the MATLAB platform. Logistic regression analysis and receiver operating characteristic analysis were performed to evaluate the diagnostic performances. Three diagnostic models including subjective model, entropy model, and combined model were built and analyzed using area under the curve (AUC) analysis. There were 119 nonsolid nodules and 67 part-solid nodules. Significant differences were found in the subjective CT features among nodule type, lesion size, lobulated shape, and irregular margin between the MIA and IAC groups. Multivariate analysis revealed that part-solid type and lobulated shape were significant independent factors for IAC (P < 0.0001 and P < 0.0001, respectively). Three entropy parameters including Entropy-0.8, Entropy-2.0-32, and Entropy-2.0-64 were identified as independent risk factors for the differentiation of MIA and IAC lesions. The median entropy model value of the MIA group was 0.266 (range, 0.174-0.590), which was significantly lower than the IAC group with value 0.815 (range, 0.623-0.901) (P < 0.0001). Multivariate analysis revealed that the combined model had an excellent diagnostic performance with sensitivity of 88.2%, specificity of 73.0%, and accuracy of 82.1%. The AUC value of the combined model was significantly higher (AUC, 0.869) than that of the subjective model (AUC, 0.809) or the entropy model alone (AUC, 0.836) (P < 0.0001). The CT-based entropy parameters could help assess the aggressiveness of pulmonary adenocarcinoma via quantitative analysis of intratumoral heterogeneity. The MIA can be differentiated from IAC accurately by using entropy-related parameters in peripheral pulmonary SSNs.

Value of TSCT Features for Differentiating Preinvasive and Minimally Invasive Adenocarcinoma From Invasive Adenocarcinoma Presenting as Subsolid Nodules Smaller Than 3 cm

To distinguish preinvasive (adenocarcinoma in situ/atypical adenomatous hyperplasia) and minimally invasive adenocarcinoma (MIA) from invasive adenocarcinoma (IA) appearing as solitary subsolid nodules (SSNs) less than 3 cm based on thin-section computed tomography (TSCT) features to guide therapeutic approaches. A total of 154 lesions that were histopathologically confirmed to have pre/minimally invasive adenocarcinoma (hereafter pre/MIA) and IA presenting as part-solid nodules (PSNs) or pure ground-glass nodules (pGGNs) were retrospectively reviewed. The TSCT features, including diameter, area, CT value, shape, air bronchogram, margins, and location, were compared and assessed. Receiver operating characteristic analyses were conducted to determine the cut-off values for the qualitative variables and their diagnostic performances. Of 154 nodules, 89 IA, 53 MIA, eight adenocarcinoma in situ, and four atypical adenomatous hyperplasia lesions were found. Univariate and multivariate logistic regression of the pre/MIA and IA lesions were compared and analyzed among PSNs and pGGNs. Among pGGNs, a significant difference was found in the area (p = 0.004, odds ratio [OR] = 0.124, 95% confidence interval [CI] = 0.300-0.515) between the pre/MIA and IA groups. In PSNs, significant differences were found in the diameter (p = 0.001, OR = 0.171, 95% CI = 0.063-0.467) and CT value (p = 0.001, OR = 0.996, 95% CI = 0.993-0.998) between the pre/MIA and IA groups. According to the corresponding receiver operating characteristic curves, the optimal cut-off tumor area in pGGNs to differentiate pre/MIA from IA was 0.595 cm2. A higher CT value of the lesion (≥ -298.500 HU) and a larger diameter (≥1.450 cm) in PSNs were significantly associated with IA. Imaging features from TSCT contribute to distinguishing pre/MIA from IA in solitary subsolid nodules and may contribute to guide the clinical management of these lesions.

Utility of Maximum Standard Uptake Value as a Predictor for Differentiating the Invasiveness of T1 Stage Pulmonary Adenocarcinoma

BackgroundThe present study was performed to investigate the maximum standardized uptake value (SUVmax) in 2-[fluorine-18]-fluoro-2-deoxy-d-glucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) to preoperatively distinguish invasive from less-invasive pulmonary adenocarcinoma. Patients and MethodsA total of 106 patients with resectable pulmonary adenocarcinoma (≤ 3 cm) who had undergone whole-body 18F-FDG PET/CT were enrolled. The SUVmax, diameter, and consolidation/tumor (C/T) ratio of the lung tumors were measured with 18F-FDG PET/CT and regional thin-section CT. ResultsOf the 106 patients, 32 had adenocarcinoma in situ (AIS), 13 had minimally invasive adenocarcinoma (MIA), and 61 had invasive adenocarcinoma (IAC). IAC lesions showed greater uptake of 18F-FDG, a larger tumor diameter, and greater C/T ratios than AIS and MIA (P < .001 for all). A multivariate analysis revealed that only the SUVmax, tumor diameter, and C/T ratio were independent risk factors for tumor invasiveness (P < .05 for all). The best cutoff values for the prediction of invasiveness were 2.15 for the SUVmax, 1.36 cm for the tumor diameter, and 0.36 for the C/T ratio. The SUVmax, tumor diameter, and C/T ratio showed similar predictive sensitivity (83.6%, 82.0%, and 88.5%, respectively). However, the SUVmax showed a greater predictive specificity than the C/T ratio (93.3% vs. 73.3%, respectively; P = .011) but similar to that of the tumor diameter. The predictive sensitivity and specificity were not improved using the 3 combined parameters compared with SUVmax alone. ConclusionThe present study has demonstrated that the SUVmax is a good preoperative predictor for the invasiveness of pulmonary adenocarcinoma (≤ 3 cm). It will help surgeons plan low invasive treatment of preinvasive tumors.

Novel Assay to Detect RNA Polymerase I Activity In Vivo.

This report develops an analytically validated chromogenic in situ hybridization (CISH) assay using branched DNA signal amplification (RNAscope) for detecting the expression of the 5' external transcribed spacer (ETS) of the 45S ribosomal (r) RNA precursor in formalin-fixed and paraffin-embedded (FFPE) human tissues. 5'ETS/45S CISH was performed on standard clinical specimens and tissue microarrays (TMA) from untreated prostate carcinomas, high-grade prostatic intraepithelial neoplasia (PIN), and matched benign prostatic tissues. Signals were quantified using image analysis software. The 5'ETS rRNA signal was restricted to the nucleolus. The signal was markedly attenuated in cell lines and in prostate tissue slices after pharmacologic inhibition of RNA polymerase I (Pol I) using BMH-21 or actinomycin D, and by RNAi depletion of Pol I, demonstrating validity as a measure of Pol I activity. Clinical human prostate FFPE tissue sections and TMAs showed a marked increase in the signal in the presumptive precursor lesion (high-grade PIN) and invasive adenocarcinoma lesions (P = 0.0001 and P = 0.0001, respectively) compared with non-neoplastic luminal epithelium. The increase in 5'ETS rRNA signal was present throughout all Gleason scores and pathologic stages at radical prostatectomy, with no marked difference among these. This precursor rRNA assay has potential utility for detection of increased rRNA production in various tumor types and as a novel companion diagnostic for clinical trials involving Pol I inhibition.Implications: Increased rRNA production, a possible therapeutic target for multiple cancers, can be detected with a new, validated assay that also serves as a pharmacodynamic marker for Pol I inhibitors. Mol Cancer Res; 15(5); 577-84. ©2017 AACR.

Abstract LB-186: Development and validation of a novel RNA in situ hybridization assay to detect RNA polymerase I activity in vivo

Abstract Increased ribosome biogenesis is a critical process requisite for the cancer cell phenotype as it is required to doulbe protein levels for cell replication. Ribosome synthesis is a complex process that is stimulated by a number of well-studied oncogenic pathways (MYC, mTOR, RAS-RAF-ERK) and repressed by tumor suppressors (pRb, p53, PTEN, p14/ARF). A key first step in ribosome biogenesis is the increased synthesis by RNA Polymerase I (Pol I) of the precursor rRNA, referred to as 45S rRNA, that is later processed into the 28S, 5.8S and 18S mature rRNA forms. This process is compartmentalized into the nucleolus. As such, the pharmacological inhibition of RNA Pol I is becoming a potentially important therapeutic strategy in cancer (PMIDs 20055700, 23953479, 24434211). A validated assay that can reflect relative levels of Pol I activity in routinely obtained tissue specimens would be a useful tool. For example it would allow the pretreatment screening (as a predictive biomarker) for those tumors likely to respond to Pol I inhibition, and, could also serve as a pharmacodynamic biomarker of Pol I inhibition. The 5’ external transcribed spacer (5’ETS) of the nascent precursor 45S transcript is rapidly removed and degraded; thus, its levels can be used as a surrogate for new rRNA transcription. We employed branched DNA amplified RNA in situ hybridization using probes developed with Advanced Cellular Diagnostics (ACD RNAscope 2.0). The 5’ ETS/45S CISH signal was restricted to nucleoli. The signal was markedly attenuated in cell lines and in formalin fixed paraffin embedded (FFPE) prostate tissue slices after pharmacological inhibition of RNA Pol I using BMH-21 or actinomycin D, demonstrating validity as a measure of RNA Pol I transcriptional activity. In clinical human prostate FFPE tissue sections and TMAs there was a marked increase in the signal in the presumptive precursor lesion (high grade prostatic intraepithelial neoplasia/HGPIN, n = 25) and in invasive adenocarcinoma lesions (n = 72, Kruskal-Wallis, p = 0.0001 and p = 0.0001, respectively) compared with normal luminal epithelium. These results are consistent with prior work using RT-PCR showing an increase in 5’ ETS/45S rRNA levels in prostate cancer tissues. In adenocarcinomas, the increase in 5’ ETS/45S signal was present throughout all Gleason scores and pathological stages at radical prostatectomy, with no marked difference among these. We developed and analytically validated a chromogenic in situ hybridization (CISH) protocol using RNAscope for detecting the 5’ external transcribed spacer (ETS) of the precursor 45S ribosomal RNA in FFPE human tissues. This novel assay was used to show increased rRNA transcription in human clinical samples of PIN and carcinoma, and should prove useful for detection of increased rRNA production in various tumor types and as a novel pharmacodynamic biomarker in clinical trials of RNA Pol I inhibitors. Citation Format: Gunes Guner, Paul Sirajuddin, Qizhi Zheng, Hester Liu, Ibrahim Kulac, Marikki K. Laiho, Angelo M. De Marzo. Development and validation of a novel RNA in situ hybridization assay to detect RNA polymerase I activity in vivo. [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 LB-186.

Abstract 1086: MYC overexpression combined with Pten loss generates genomic instability and rapid metastasis in a new mouse model of lethal prostate adenocarcinoma.

Abstract There is a pressing need for animal models that recapitulate key pathological features of lethal human prostate adenocarcinoma. The availability of these models would facilitate studies to elucidate the molecular events underlying disease progression, and would be invaluable for evaluating new treatment efficacy. Within extant mouse models, metastasis is rare and typically occurs at an advanced age. Using a bacterial artificial chromosome-based transgenic approach, we generated mice in which Hoxb13 regulatory elements drive expression of human MYC (Hoxb13MYC+) or Cre recombinase (Hoxb13Cre+). Hoxb13Cre+ mice were bred to mice carrying floxed Pten (Ptenfl) alleles to generate focal loss of Pten in the prostate epithelium. We then generated mice carrying both the Hoxb13MYC+ and Hoxb13Cre+ transgenes that also harbored two Ptenfl alleles. Phenotypic analyses of Hoxb13MYC+|Hoxb13Cre+| Ptenfl/fl males revealed pervasive low-grade mouse-PIN (mPIN) in all prostate lobes emerging at two weeks of age that became pervasive that progressed to high-grade mPINby four weeks. The lesions bore hallmarks of human PIN including increased nuclear and nucleolar size and dispersed chromatin. Immunostaining revealed MYC and androgen receptor expression and focal Pten loss within the epithelial compartment. mPIN incidence high-gradewas higher in ventral and anterior lobes. By twelve weeks, lesions progressed to cribriform mPIN/intraductal carcinoma was widespread and scattered intraductal carcinoma lesions were observed. At sixteen weeks, in all animals, large frank invasive adenocarcinoma lesions involving multiple prostate lobes were was present as well as, and histological analyses confirmed the presence of invasive poorly differentiated adenocarcinoma. Interestingly, by 16 weeks, metastasis to pelvic and peritoneal lymph nodes occurred with 100% penetrance. In survival analyses, all Hoxb13MYC+|Hoxb13Cre+| Ptenfl/fl mice (N=12) reached criteria for euthanasia within 28 weeks. Liver and lung metastases were observed with high penetrance (&amp;gt;80%). In one case, metastatic spread to a thoracic vertebra was observed, which may represent the first hematogenous metastasis to bone in a mouse prostate cancer model. Copy number analyses using array-based comparative genomic hybridization revealed clonal gene gains and losses in primary prostate cancers and matched metastatic lesions, indicative of genomic instability. The incidence of aggressive cancer and the reproducible chronology of events will enable this model to serve as a robust platform to test strategies to interfere with disease initiation and progression. The lethal phenotype will permit analyses of potentially life extending therapies. In addition, these features will enable studies to dissect the pivotal molecular events that drive the stepwise progression/evolution of this disease. Citation Format: Gretchen K. Hubbard, Laura N. Mutton, May Khalili, Ryan P. McMullin, Jessica Hicks, Daniella Bianchi-Frias, Peter S. Nelson, Srinivasan Yegnasubramanian, Angelo M. De Marzo, Charles J. Bieberich. MYC overexpression combined with Pten loss generates genomic instability and rapid metastasis in a new mouse model of lethal prostate adenocarcinoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1086. doi:10.1158/1538-7445.AM2013-1086

Global Levels of H3K27me3 Track with Differentiation in Vivo and Are Deregulated by MYC in Prostate Cancer

Cancer cells and stem cells share a number of biological characteristics including abundant amounts of decondensed chromatin. However, the molecular correlates and the factors involved in altering chromatin structure in cancer cells are not well known. Here, we report that less differentiated stem-like cells in the basal compartment of human and mouse prostate contain lower levels of the polycomb heterochromatin marker H3K27me3 than more differentiated luminal cells. This link to differentiated normal cells is also found in a number of other human and rodent tissues characterized by hierarchical differentiation. In addition to MYC's traditional role as a gene-specific transcription factor, recent studies indicate that MYC also affects global chromatin structure where it is required to maintain "open" or active chromatin. We now demonstrate that in both MYC-driven prostate cancers in mice and human prostate cancers, global levels of H3K27me3 are reduced in prostatic intraepithelial neoplasia and invasive adenocarcinoma lesions. Moreover, decreased levels of H3K27me3 correlate with increased markers of disease aggressiveness (eg, Gleason score and pathological stage). In vitro, experimentally forced reductions in MYC levels result in increased global levels of H3K27me3. These findings suggest that increased levels of decondensed chromatin in both normal progenitor cells and cancer cells are associated with global loss of H3K27me3, which is linked to MYC overexpression.

Abstract 2210: Global levels of H3K27me3 track with differentiation in vivo and are deregulated by MYC in prostate cancer

Abstract Both embryonic stem cells and various cancer cell types contain abundant amounts of decondensed chromatin. However, the molecular mechanisms responsible for altering chromatin states in stem cells and cancer cells are not well understood. One factor may be the oncogenic transcription factor, MYC. MYC is overexpressed in many tumor types and affects a wide array of essential cellular processes including ribosome and mitochondrial biogenesis, metabolism, and cell cycle progression. MYC is also a key factor in reprogramming of somatic adult cells into induced pluripotent stem cells. Less well known is that MYC also affects global chromatin structure where it is required to maintain open or active chromatin. We hypothesize that in prostate cancer, MYC affects global chromatin structure keeping it in a more open conformation thus maintaining the cells in a less differentiated state resembling that of stem cells. We show by immunohistochemistry that compared to the more differentiated luminal cells, less differentiated stem-like cells in the basal compartment of the human and mouse prostate contain lower levels of the polycomb heterochromatin mark, H3K27me3. This link to the differentiated state of normal cells is also found in a number of other human and rodent tissues characterized by hierarchical differentiation and rapid turnover of stem cell compartments. Further, in MYC-driven prostate cancers in mice, global levels of H3K27me3 are reduced in both prostatic intraepithelial neoplasia (PIN) and invasive adenocarcinoma lesions. This pattern of global H3K27me3 reduction in PIN and invasive prostate cancers is also observed in humans, correlates with global chromatin decondensation, and correlates with increased markers of disease aggressiveness (e.g. Gleason score and pathological stage). In prostate and breast cancer cells, experimentally forced reductions in MYC levels result in increased global levels of H3K27me3. These findings suggest that increased levels of decondensed chromatin in normal stem/progenitor cells and in cancer cells are associated with global loss of the H3K27me3 polycomb mark, and furthermore, MYC overexpression could be one mechanism for this H3K27me3 deregulation. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2210. doi:1538-7445.AM2012-2210

Abstract LB-51: Pten null prostate tumorigenesis and prostate stem cell activity are inhibited by targeted knockout of the Survivin gene

Abstract Survivin, a member of the inhibitor of apoptosis family, is highly expressed in various cancers including prostate cancer. In the conditional Pten deletion mouse model, we showed a correlation between increased levels of survivin with the growth of the prostate tumor (Cancer Res. 66: 4285–90, 2006), and more recently described that high levels of survivin might also be associated with the cancer stem cells of this model (Cancer Res. 70: 7294–303, 2010). Here we report that homozygous deletion of the Survivin gene specifically in mouse prostate epithelium suppresses prostate tumorigenesis without affecting postnatal prostate development and growth. Mouse prostates with double conditional knockout of Survivin and Pten that were collected at 8.5 weeks of age appear to exhibit normal gross morphology, histology and cytology, in contrast to the detection of hyperplasia, dysplasia and prostatic intraepithelial neoplasia (PIN) lesions in mouse prostates with bi-allelic Pten inactivation. While the mice with Pten deletion alone uniformly develop numerous invasive adenocarcinoma lesions in all of the prostate lobes by 17–20 weeks of age, our analysis to date of a single double knockout animal at 17 weeks reveals mostly PIN lesions in the anterior and the ventral prostate lobes with the dorsolateral lobe exhibiting detectable foci of adenocarcinoma. As the animals age, increased number of animals at this age and other advancing age groups remain to be evaluated for the significance of this observation and the possibility that the isolated lesions detected in the double knockout might be related to incomplete recombination in Survivin alleles in the target cells remains to be tested. In general, we observe a dramatic reduction in the proliferation index, as assessed by Ki67 staining, in the prostate tissue with the double deletion of Pten and Survivin compared to Pten deletion alone. We propose that survival of the proliferating abnormal cells is compromised by the intracellular loss of survivin. We used adenovirus-Cre to knock-out Survivin in stem cell fractions isolated from the prostate of the normal mouse with floxed Survivin alleles. It is very interesting to find that loss of survivin significantly lowers in vitro proliferation, spheroid-forming capability and survival potential of these cells, implicating a strong cytoprotective role of survivin for the prostate stem cells. Thus, it would now be important to extend the study for evaluation of the function of survivin in the prostate cancer stem cells, a compartment that may indeed be critical to the process of prostate tumorigenesis. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-51. doi:10.1158/1538-7445.AM2011-LB-51

Alterations of HLA class I and II antigen expression in preinvasive, invasive and metastatic cervical cancers.

HLA expression is altered in a large variety of human cancers. We performed immunohistochemical staining on tissues from normal, preinvasive, invasive and metastatic cervical cancer tissues using anti-HLA class I or class II antibody. In tissues from normal squamous epithelium, carcinoma in situ (CIS) and microinvasive carcinoma (MIC), the expressions of HLA-B, C heavy chains and class II heavy chain were significantly decreased as disease progressed. When the expression patterns were compared between primary and metastatic squamous cell carcinoma (SCC) lesions, statistically significant down-regulation of HLA class I and class II antigen in metastatic lesions was observed. The rates of HLA-B, C heavy chains and class II heavy chain expressions were all significantly down-regulated compared to the down-regulation rate of class I beta2-microglobulin (beta2m) in invasive squamous lesions, and the expressions of class II heavy chain in metastatic lesions was decreased further than that in primary lesions. Unlike SCC, the degree of HLA class I and class II loss was not evident as disease progressed in early stage of adenocarcinoma. In invasive adenocarcinoma lesions, only the expression of HLA-B, C heavy chains was decreased and no differences were seen in HLA-B, C heavy chain expression patterns between primary and metastatic lesions. These results suggest that alterations of HLA class I and II expressions seem to occur at a particular step in cervical cancer development and depend on tissue types: when the tumor becomes invasive and starts to metastasize.