Joan G. Jones

Progression to Malignancy in the Polyoma Middle T Oncoprotein Mouse Breast Cancer Model Provides a Reliable Model for Human Diseases

Animal models are powerful tools to analyze the mechanism of the induction of human breast cancer. Here we report a detailed analysis of mammary tumor progression in one mouse model of breast cancer caused by expression of the polyoma middle T oncoprotein (PyMT) in the mammary epithelium, and its comparison to human breast tumors. In PyMT mice, four distinctly identifiable stages of tumor progression from premalignant to malignant stages occur in a single primary tumor focus and this malignant transition is followed by a high frequency of distant metastasis. These stages are comparable to human breast diseases classified as benign or in situ proliferative lesions to invasive carcinomas. In addition to the morphological similarities with human breast cancer, the expression of biomarkers in PyMT-induced tumors is also consistent with those associated with poor outcome in humans. These include a loss of estrogen and progesterone receptors as well as integrin-beta1 expression and the persistent expression of ErbB2/Neu and cyclinD1 in PyMT-induced tumors as they progress to the malignant stage. An increased leukocytic infiltration was also closely associated with the malignant transition. This study demonstrates that the PyMT mouse model is an excellent one to understand the biology of tumor progression in humans.

Cyclin D1 Repression of Peroxisome Proliferator-Activated Receptor γ Expression and Transactivation

ABSTRACT The cyclin D1 gene is overexpressed in human breast cancers and is required for oncogene-induced tumorigenesis. Peroxisome proliferator-activated receptor γ (PPARγ) is a nuclear receptor selectively activated by ligands of the thiazolidinedione class. PPARγ induces hepatic steatosis, and liganded PPARγ promotes adipocyte differentiation. Herein, cyclin D1 inhibited ligand-induced PPARγ function, transactivation, expression, and promoter activity. PPARγ transactivation induced by the ligand BRL49653 was inhibited by cyclin D1 through a pRB- and cdk-independent mechanism, requiring a region predicted to form an helix-loop-helix (HLH) structure. The cyclin D1 HLH region was also required for repression of the PPARγ ligand-binding domain linked to a heterologous DNA binding domain. Adipocyte differentiation by PPARγ-specific ligands (BRL49653, troglitazone) was enhanced in cyclin D1−/− fibroblasts and reversed by retroviral expression of cyclin D1. Homozygous deletion of the cyclin D1 gene, enhanced expression by PPARγ ligands of PPARγ and PPARγ-responsive genes, and cyclin D1−/− mice exhibit hepatic steatosis. Finally, reduction of cyclin D1 abundance in vivo using ponasterone-inducible cyclin D1 antisense transgenic mice, increased expression of PPARγ in vivo. The inhibition of PPARγ function by cyclin D1 is a new mechanism of signal transduction cross talk between PPARγ ligands and mitogenic signals that induce cyclin D1.

EGF stimulates lamellipod extension in metastatic mammary adenocarcinoma cells by an actin-dependent mechanism

Changes in lamellipod extension and chemotaxis in response to EGF were analysed for MTLn3 cells (a metastatic cell line derived from the 13762NF rat mammary adenocarcinoma). Addition of EGF produced a cessation of ruffling followed by extension of hyaline lamellipods containing increased amounts of F-actin at the growing edge. A non-metastatic cell line (MTC) derived from the same tumor did not show such responses. Lamellipod extension was maximal within 5 min, followed by retraction and resumption of ruffling. Maximal area increases due to lamellipod extension occurred at about 5 nM EGF. Chemotactic and chemokinetic responses, measured using a microchemotaxis chamber, were also greatest at 5 nm. Cytochalasin D inhibited EGF-stimulated responses including lamellipod extension, increases in F-actin in lamellipods, and chemotaxis. Nocodazole affected chemotaxis at higher concentrations but not EGF-induced lamellipod extension. We conclude that polymerization of F-actin at the leading edges of lamellipods is necessary for extension of lamellipods and chemotaxis of MTLn3 cells in response to EGF. The motility and chemotaxis responses of this metastatic cell line have strong similarities to those seen in well-characterized chemotactic cells such as Dictyostelium and neutrophils.

Real-Time Imaging Reveals Local, Transient Vascular Permeability, and Tumor Cell Intravasation Stimulated by TIE2hi Macrophage–Derived VEGFA

UNLABELLED Dissemination of tumor cells is an essential step in metastasis. Direct contact between a macrophage, mammalian-enabled (MENA)-overexpressing tumor cell, and endothelial cell [Tumor MicroEnvironment of Metastasis (TMEM)] correlates with metastasis in breast cancer patients. Here we show, using intravital high-resolution two-photon microscopy, that transient vascular permeability and tumor cell intravasation occur simultaneously and exclusively at TMEM. The hyperpermeable nature of tumor vasculature is described as spatially and temporally heterogeneous. Using real-time imaging, we observed that vascular permeability is transient, restricted to the TMEM, and required for tumor cell dissemination. VEGFA signaling from TIE2(hi) TMEM macrophages causes local loss of vascular junctions, transient vascular permeability, and tumor cell intravasation, demonstrating a role for the TMEM within the primary mammary tumor. These data provide insight into the mechanism of tumor cell intravasation and vascular permeability in breast cancer, explaining the value of TMEM density as a predictor of distant metastatic recurrence in patients. SIGNIFICANCE Tumor vasculature is abnormal with increased permeability. Here, we show that VEGFA signaling from TIE2(hi) TMEM macrophages results in local, transient vascular permeability and tumor cell intravasation. These data provide evidence for the mechanism underlying the association of TMEM with distant metastatic recurrence, offering a rationale for therapies targeting TMEM.

Tumor Microenvironment of Metastasis and Risk of Distant Metastasis of Breast Cancer

BACKGROUND Tumor microenvironment of metastasis (TMEM), consisting of direct contact between a macrophage, an endothelial cell, and a tumor cell, has been associated with metastasis in both rodent mammary tumors and human breast cancer. We prospectively examined the association between TMEM score and risk of distant metastasis and compared risk associated with TMEM score with that associated with IHC4. METHODS We conducted a case-control study nested within a cohort of 3760 patients with invasive ductal breast carcinoma diagnosed between 1980 and 2000 and followed through 2010. Case patients were women who developed a subsequent distant metastasis; control subjects were matched (1:1) on age at and calendar year of primary diagnosis. TMEM was assessed by triple immunostain and IHC4 by standard methods; slides were read by pathologists blinded to outcome. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression, adjusted for clinical variables. A Receiver Operating Characteristic analysis was performed, and the area under the curve was estimated. All statistical tests were two-sided. RESULTS TMEM score was associated with increased risk of distant metastasis in estrogen receptor (ER)(+)/human epidermal growth factor receptor (HER2)(-) tumors (multivariable OR high vs low tertile = 2.70; 95% CI = 1.39 to 5.26; P trend = .004), whereas IHC4 score had a borderline positive association (OR10 unit increase = 1.06; 95% CI = 1.00 to 1.13); the association for TMEM score persisted after adjustment for IHC4 score. The area under the curve for TMEM, adjusted for clinical variables, was 0.78. Neither TMEM score nor IHC4 score was independently associated with metastatic risk overall or in the triple negative or HER2(+) subgroups. CONCLUSIONS TMEM score predicted risk of distant metastasis in ER(+)/HER2(-) breast cancer independently of IHC4 score and classical clinicopathologic features.

Expression of COX-2, Ki-67, cyclin D1, and P21 in endometrial endometrioid carcinomas.

COX-2, the isoform of cyclooxygenase inducible by cytokines, mitogens, and growth factors, appears to play an important role in inflammation and carcinogenesis. In the colon, COX-2 overexpression results in cell cycle alterations, and NSAIDs have proven effective in cancer chemoprevention. HNPCC (hereditary nonpolyposis colon cancer) is a clinically defined cancer susceptibility syndrome in which women are also at significantly increased risk for the development of endometrial carcinoma. The purpose of this study was to evaluate expression of COX-2 in benign and malignant endometrium in the context of other cell cycle and proliferation markers, including Ki-67, cyclin D1, and the cyclin-dependent kinase inhibitor, p21. Immunostains with COX-2, Ki-67, cyclin D1, and p21 antibodies were performed on formalin-fixed and paraffin-embedded tissue sections from 40 cases: 10 benign (5 atrophic and 5 proliferative) endometria, 6 hyperplasias (complex without atypia), and 24 endometrioid carcinomas (9 well, 4 moderately, and 11 poorly differentiated). Ki-67 was positive in all proliferative and neoplastic endometria. Cyclin D1 and p21 were both overexpressed in endometrial hyperplasia and endometrioid carcinomas. COX-2 was negative in the nonneoplastic endometrium, stained minimally in the well-differentiated endometrioid carcinomas, and stained most strongly in the moderately and poorly differentiated endometrioid carcinomas. Because cyclin D1 may function as an oncogene, its effects may dominate the usual inhibitory effect of a rising p21. Alternatively, it has been shown that p21 can promote cell cycle function by stabilizing cell cycle complexes. The overexpression of COX-2 in poorly differentiated endometrioid carcinoma and lack of expression in hyperplasia and well-differentiated carcinoma suggests that in this form of cancer, COX-2 may play a role in tumor progression rather than tumor initiation.

Virulence of papillary endometrial carcinoma

While uterine papillary serous carcinoma (UPSC) has been well described as a virulent subtype of endometrial adenocarcinoma (AC), with behavior similar to that of papillary serous ovarian carcinoma, the papillary endometrial (PE) variant has not been well characterized. We studied 117 patients with endometrial carcinoma identified by our tumor registry, pathology files, and practice records from March 1981 to February 1989: 76 with AC, 26 with PE, and 15 with UPSC. Age and demographic data were similar for all three groups. All of the AC patients, 84% of PE patients, and 87% of UPSC patients had early-stage disease by clinical exam; however, 10% of AC patients, 23% of PE patients, and 87% of UPSC patients had extrauterine disease at surgery (P less than 0.05). Deep myometrial invasion occurred in 29% of AC patients, 36% of PE patients, and 60% of UPSC patients (P less than 0.05). Comparative analysis of the PE and UPSC groups revealed more marked nuclear anaplasia (P less than 0.05) and more frequent vascular space involvement (nonsignificant) in the UPSC group. At 3 years, 75% of the AC group was alive without disease. In contrast, the median progression-free interval for the PE group was 33 months, and for the UPSC group, 9 months (P less than 0.05). These data suggest a transition of increasing virulence corresponding with increasing papillary features, from AC to PE to UPSC. The papillary feature may be a new, significant risk factor in endometrial carcinoma.

Differential expression of WT1 and p53 in serous and endometrioid carcinomas of the endometrium

Summary:Wilms’ tumor antibody (WT1) has recently been reported to be reactive in most ovarian and peritoneal serous carcinomas, but few studies have looked at WT1 reactivity in endometrial carcinomas. p53, like WT1, is a tumor suppressor gene and in its mutated form is frequently present in endometrial serous carcinoma. Routine immunohistochemical staining for p53 and WT1 was performed in 70 endometrial carcinomas (39 endometrioid and 31 serous) of varying differentiation using tissue microarrays. Only 2 (7.5%) serous carcinomas and none of the endometrioid carcinomas (0%) were reactive for WT1. p53 immunoreactivity was found in 26 (83.9%) serous carcinomas and in 2 (5.1%) endometrioid carcinomas. We conclude that WT1 and p53 expression are not related and that WT1 expression in endometrial serous carcinoma differs from that of its extrauterine counterparts.

Mena invasive (MenaINV) and Mena11a isoforms play distinct roles in breast cancer cell cohesion and association with TMEM

Mena, an actin regulatory protein, functions at the convergence of motility pathways that drive breast cancer cell invasion and migration in vivo. The tumor microenvironment spontaneously induces both increased expression of the Mena invasive (MenaINV) and decreased expression of Mena11a isoforms in invasive and migratory tumor cells. Tumor cells with this Mena expression pattern participate with macrophages in migration and intravasation in mouse mammary tumors in vivo. Consistent with these findings, anatomical sites containing tumor cells with high levels of Mena expression associated with perivascular macrophages were identified in human invasive ductal breast carcinomas and called TMEM. The number of TMEM sites positively correlated with the development of distant metastasis in humans. Here we demonstrate that mouse mammary tumors generated from EGFP-MenaINV expressing tumor cells are significantly less cohesive and have discontinuous cell–cell contacts compared to Mena11a xenografts. Using the mouse PyMT model we show that metastatic mammary tumors express 8.7 fold more total Mena and 7.5 fold more MenaINV mRNA than early non-metastatic ones. Furthermore, MenaINV expression in fine needle aspiration biopsy (FNA) samples of human invasive ductal carcinomas correlate with TMEM score while Mena11a does not. These results suggest that MenaINV is the isoform associated with breast cancer cell discohesion, invasion and intravasation in mice and in humans. They also imply that MenaINV expression and TMEM score measure related aspects of a common tumor cell dissemination mechanism and provide new insight into metastatic risk.

Adjuvant therapy for neuroendocrine small cell carcinoma of the cervix: Review of the literature

Neuroendocrine cell carcinoma of the cervix is a virulent tumor associated with an extremely poor prognosis. Even in clinical Stage I disease, there may be subclinical hematogenous and lymphatic metastases with frequent recurrences. Adjuvant postoperative external pelvic radiotherapy has been reported to offer some degree of local control; however, most patients succumb to distant disease. Following radical abdominal hysterectomy and pelvic lymphadenectomy, with confirmation of the neuroendocrine tumor by electron microscopy and immunohistochemical staining, two patients were given adjuvant systemic chemotherapy with concurrent pelvic radiotherapy, employing regimens with documented activity against small cell carcinoma of the lung of neuroendocrine origin. Despite severe myelotoxicity and persistent neuropathy, both patients are alive without clinical evidence of disease at 28+ and 47+ months.