Control of nutrient stress-induced metabolic reprogramming by PKCζ in tumorigenesis.

Tumor cells have high-energetic and anabolic needs and are known to adapt their metabolism to be able to survive and keep proliferating under conditions of nutrient stress. We show that PKCζ deficiency promotes the plasticity necessary for cancer cells to reprogram their metabolism to utilize glutamine through the serine biosynthetic pathway in the absence of glucose. PKCζ represses the expression of two key enzymes of the pathway, PHGDH and PSAT1, and phosphorylates PHGDH at key residues to inhibit its enzymatic activity. Interestingly, the loss of PKCζ in mice results in enhanced intestinal tumorigenesis and increased levels of these two metabolic enzymes, whereas patients with low levels of PKCζ have a poor prognosis. Furthermore, PKCζ and caspase-3 activities are correlated with PHGDH levels in human intestinal tumors. Taken together, this demonstrates that PKCζ is a critical metabolic tumor suppressor in mouse and human cancer.

Simultaneous Loss of Both Atypical Protein Kinase C Genes in the Intestinal Epithelium Drives Serrated Intestinal Cancer by Impairing Immunosurveillance.

Serrated adenocarcinoma, an alternative pathway for colorectal cancer (CRC) development, accounts for 15%-30% of all CRCs and is aggressive and treatment resistant. We show that the expression of atypical protein kinase C ζ (PKCζ) and PKCλ/ι was reduced in human serrated tumors. Simultaneous inactivation of the encoding genes in the mouse intestinal epithelium resulted in spontaneous serrated tumorigenesis that progressed to advanced cancer with a strongly reactive and immunosuppressive stroma. Whereas epithelial PKCλ/ι deficiency led to immunogenic cell death and the infiltration of CD8+ T cells, which repressed tumor initiation, PKCζ loss impaired interferon and CD8+ T cell responses, which resulted in tumorigenesis. Combined treatment with a TGF-ß receptor inhibitor plus anti-PD-L1 checkpoint blockade showed synergistic curative activity. Analysis of human samples supported the relevance of these kinases in the immunosurveillance defects of human serrated CRC. These findings provide insight into avenues for the detection and treatment of this poor-prognosis subtype of CRC.

c-Myc phosphorylation by PKCζ represses prostate tumorigenesis.

Studies showing reduced PKCζ expression or enzymatic activity in different types of human cancers support the clinical relevance of PKCζ as a tumor suppressor. However, the in vivo role of PKCζ and its mechanisms of action in prostate cancer remain unclear. Here we demonstrate that the genetic inactivation of PKCζ in mice results in invasive prostate carcinoma in vivo in the context of phosphatase and tensin homolog deficiency. Bioinformatic analysis of human prostate cancer gene-expression sets revealed increased c-Myc transcriptional activity in PKCζ-inactive cells, which correlated with increased cell growth, invasion, and metastasis. Interestingly, PKCζ knockdown or the overexpression of a kinase-inactive mutant resulted in enhanced cell proliferation and invasion in vitro through increased c-Myc mRNA and protein levels and decreased Ser-373 phosphorylation of c-Myc. Analysis of prostate cancer samples demonstrated increased expression and decreased phosphorylation of c-Myc at Ser-373 in PKCζ knockout tumors. In vivo xenograft studies revealed that c-Myc phosphorylation by PKCζ is a critical event in the control of metastasis. Collectively, these results establish PKCζ as an important tumor suppressor and regulator of c-Myc function in prostate cancer.

Primary esophageal meningioma: first literature report.

We have described a primary esophageal meningioma (MG) clinical case diagnosed in a 62-year-old woman; also, we review the literature about extracranial MGs. To our knowledge, this is the first case report of an extracranial MG occurring primarily in the esophagus. These are benign neoplasms reported classically in the central nervous system (CNS). The extrancranial MGs have histopathologic and inmunohistochemical features identical to those observed in CNS MGs; thus, the main diagnostic hurdle is to keep it in the differential for lesions occurring outside the CNS.

Simultaneous inactivation of Par-4 and PTEN in vivo leads to synergistic NF-kappaB activation and invasive prostate carcinoma.

Prostate cancer is one of the most common neoplasias in men. The tumor suppressor Par-4 is an important negative regulator of the canonical NF-kappaB pathway and is highly expressed in prostate. Here we show that Par-4 expression is lost in a high percentage of human prostate carcinomas, and this occurs in association with phosphatase and tensin homolog deleted from chromosome 10 (PTEN) loss. Par-4 null mice, similar to PTEN-heterozygous mice, only develop benign prostate lesions, but, importantly, concomitant Par-4 ablation and PTEN-heterozygosity lead to invasive prostate carcinoma in mice. This strong tumorigenic cooperation is anticipated in the preneoplastic prostate epithelium by an additive increase in Akt activation and a synergistic stimulation of NF-kappaB. These results establish the cooperation between Par-4 and PTEN as relevant for the development of prostate cancer and implicate the NF-kappaB pathway as a critical event in prostate tumorigenesis.

Adipocyte p62/SQSTM1 Suppresses Tumorigenesis through Opposite Regulations of Metabolism in Adipose Tissue and Tumor.

Obesity is a leading risk factor for cancer. However, understanding the crosstalk between adipocytes and tumor cells in vivo, independently of dietary contributions, is a major gap in the field. Here we used a prostate cancer (PCa) mouse model in which the signaling adaptor p62/Sqstm1 is selectively inactivated in adipocytes. p62 loss in adipocytes results in increased osteopontin secretion, which mediates tumor fatty acid oxidation and invasion, leading to aggressive metastatic PCa in vivo. Furthermore, p62 deficiency triggers in adipocytes a general shutdown of energy-utilizing pathways through mTORC1 inhibition, which supports nutrient availability for cancer cells. This reveals a central role of adipocyte's p62 in the symbiotic adipose tissue-tumor collaboration that enables cancer metabolic fitness.

ATF4-Induced Metabolic Reprograming Is a Synthetic Vulnerability of the p62-Deficient Tumor Stroma.

Tumors undergo nutrient stress and need to reprogram their metabolism to survive. The stroma may play a critical role in this process by providing nutrients to support the epithelial compartment of the tumor. Here we show that p62 deficiency in stromal fibroblasts promotes resistance to glutamine deprivation by the direct control of ATF4 stability through its p62-mediated polyubiquitination. ATF4 upregulation by p62 deficiency in the stroma activates glucose carbon flux through a pyruvate carboxylase-asparagine synthase cascade that results in asparagine generation as a source of nitrogen for stroma and tumor epithelial proliferation. Thus, p62 directly targets nuclear transcription factors to control metabolic reprogramming in the microenvironment and repress tumorigenesis, and identifies ATF4 as a synthetic vulnerability in p62-deficient tumor stroma.

The impact of genotype on outcome in oligodendroglioma: validation of the loss of chromosome arm 1p as an important factor in clinical decision making.

OBJECT: Oligodendrogliomas are rare primary brain tumors. They comprise approximately 5 to 33% of all glial tumors but differ from astrocytomas by being associated with a more favorable prognosis, making their correct identification important. Allelic loss of chromosome arms 1p and 19q is found in a substantial subpopulation of tumors with an oligodendroglioma phenotype. Anaplastic oligodendrogliomas with allelic loss of 1p have been associated with chemosensitivity and a longer patient survival period. METHODS: Oligodendroglial neoplasms were studied using fluorescence in situ hybridization of formalin-fixed, paraffin-embedded tissue specimens; reference and target probe sets were used to map the telomeric regions of 1p and 19q. The results were correlated with the clinical characteristics of patients treated at our institution between 1993 and 2003. Data obtained in 96 patients were analyzed. This included 63 patients (65.6%) with World Health Organization (WHO) Grade II oligodendroglioma, 22 (23%) with Grade III oligodendroglioma, and 11 (11.4%) with mixed oligoastrocytoma. Analysis of 1p in patients with pure oligodendroglioma revealed a loss of 1p in 42 patients (49.4%). In 46 of these patients 19q was lost and in 70 (82.3%) there was concordance for combined loss or retention of both 1p and 19q (p < 0.0001). Patients with oligodendroglioma in whom a loss of 1p was present fared significantly better, and this outcome was unrelated to the treatment modality or WHO grade, compared with patients in whom 1p was intact (p < 0.05). CONCLUSIONS: To the authors' knowledge, this study includes the largest published series of WHO Grade II oligodendroglioma and 1p analysis. The results suggest that the association between long-term survival and 1p loss in oligodendroglioma is unrelated to treatment. The authors of further prospective studies may better determine the true value of the allelic loss of 1p and its implication for clinical decision making.

p62/SQSTM1 by Binding to Vitamin D Receptor Inhibits Hepatic Stellate Cell Activity, Fibrosis, and Liver Cancer.

Hepatic stellate cells (HSCs) play critical roles in liver fibrosis and hepatocellular carcinoma (HCC). Vitamin D receptor (VDR) activation in HSCs inhibits liver inflammation and fibrosis. We found that p62/SQSTM1, a protein upregulated in liver parenchymal cells but downregulated in HCC-associated HSCs, negatively controls HSC activation. Total body or HSC-specific p62 ablation potentiates HSCs and enhances inflammation, fibrosis, and HCC progression. p62 directly interacts with VDR and RXR promoting their heterodimerization, which is critical for VDR:RXR target gene recruitment. Loss of p62 in HSCs impairs the repression of fibrosis and inflammation by VDR agonists. This demonstrates that p62 is a negative regulator of liver inflammation and fibrosis through its ability to promote VDR signaling in HSCs, whose activation supports HCC.

Cavitary mass lesion and recurrent pneumothoraces due to Paragonimus kellicotti infection: North American paragonimiasis.

North American paragonimiasis is well described in omnivorous and carnivorous animals on this continent. Humans are rarely infected, largely because of dietary customs, but are at risk for infection if raw or undercooked crayfish are consumed. We describe a patient with a pleuropulmonary infection due to Paragonimus kellicotti that presented as recurrent pneumothoraces and a cavitary lesion. This is the first case of North American paragonimiasis in which the diagnosis was based on the morphology of the eggs present in histologic sections.

Chromosome 1p allelic loss by fluorescence in situ hybridization is not observed in dysembryoplastic neuroepithelial tumors.

Differentiation of dysembryoplastic neuroepithelial tumor (DNT) from cystic low-grade oligodendroglioma, particularly in a limited biopsy orfragmented specimen, may be impossible. Research has shown that allelic loss of chromosome 1p is a relatively common finding in oligodendrogliomas. Little is known about chromosome 1p status in DNT. We retrospectively evaluated 14 DNTs for loss of heterozygosity (LOH) on chromosome 1p by fluorescence in situ hybridization (FISH) and compared the results with 1p FISH analysis in 57 low-grade oligodendrogliomas (World Health Organization grade II). The 14 DNTs arose in 8 females and 6 males (mean age, 20.9 years at the time of surgery). All 14 DNTs were 1p intact by FISH analysis. The 57 low-grade oligodendrogliomas arose in 31 males and 26 females (mean age, 43.2 years). LOH on chromosome 1p was present in 31 (54%) of 57 tumors; the remaining 26 tumors were 1p intact. LOH on chromosome 1p is not a feature of DNTs. LOH on chromosome 1p may be a useful differential diagnostic feature (favoring oligodendroglioma) in a subset of cases in which specimen fragmentation or size raises the differential diagnosis of DNT vs oligodendroglioma.

Immunohistochemical expression of cathepsin D in meningiomas.

We retrospectively studied the expression of cathepsin D by immunohistochemical analysis in 86 meningiomas (World Health Organization [WHO] grade I, n = 44; WHO grade II, n = 21; WHO grade III, n = 21) and correlated the results with tumor grade and outcome. Staining was scored semiquantitatively based on distribution among neoplastic cells as follows: 0, no staining; 1+, 5% or less of the cells; 2+, 6% to 20%; 3+, 21% to 50%; and 4+, more than 50% of the cells. Cathepsin D expression was observed as follows: 0, 10 cases (12%); 1+, 25 cases (29%); 2+, 15 cases (17%); 3+, 12 cases (14%); and 4+, 24 cases (28%). A higher degree of cathepsin D immunostaining was associated with low tumor grade (P = .0014), low mitotic count (P < .0001), low apoptotic count (P < .0001), and the development of recurrence (P = .035). There was no correlation with outcome or MIB-1 proliferation index. Cathepsin D expression by immunohistochemical analysis was identified in the majority (88% [76/86]) of meningiomas studied. A greater degree of immunoreactivity was observed in the WHO grade I group.

Adult xanthogranuloma of the vulva: case report and review.

We report a case of adult xanthogranuloma arising on the labia majora of a 48-year-old female. Although histologically similar to juvenile xanthogranuloma, the clinical presentation and natural history are unique. To our knowledge this is the first case described of this rare histiocytic lesion arising in the vulva.

Brain-invasive solitary fibrous tumor of the meninges: report of a case.

Solitary fibrous tumor is a mesenchymal neoplasm that most commonly arises in the pleura, but also in multiple extrapleural sites including, rarely, the meninges. Immunohistochemical findings facilitate its differentiation from other spindle cell lesions such as fibrous meningioma. Although the great majority of extrapleural solitary fibrous tumors behave in a benign fashion, only rare examples of brain-invasive tumors have been documented. We present a case of a brain-invasive solitary fibrous tumor arising in the meninges of a 40-year-old woman. The tumor was marked by focally prominent hypercellularity, moderate nuclear pleomorphism, and increased mitotic activity. Focal infiltration into the underlying brain parenchyma was observed. The tumor was CD34 positive and EMA negative.

Metabolic reprogramming of stromal fibroblasts through p62-mTORC1 signaling promotes inflammation and tumorigenesis.

The tumor microenvironment plays a critical role in cancer progression, but the precise mechanisms by which stromal cells influence the epithelium are poorly understood. Here we show that p62 levels were reduced in the stroma of several tumors and that its loss in the tumor microenvironment or stromal fibroblasts resulted in increased tumorigenesis of epithelial prostate cancer cells. The mechanism involves the regulation of cellular redox through an mTORC1/c-Myc pathway of stromal glucose and amino acid metabolism, resulting in increased stromal IL-6 production, which is required for tumor promotion in the epithelial compartment. Thus, p62 is an anti-inflammatory tumor suppressor that acts through the modulation of metabolism in the tumor stroma.

Prediction of adenocarcinoma in esophagectomy specimens based upon analysis of preresection biopsies of Barrett esophagus with at least high-grade dysplasia: a comparison of 2 systems.

Distinguishing Barrett esophagus with high-grade dysplasia (BE-HGD) from intramucosal and submucosal adenocarcinomas on biopsies is challenging, yet important, in the choice of therapy. The current study evaluates preresection biopsies from patients who underwent esophagectomy for at least BE-HGD, to compare the recently published histologic categories by the University of Michigan (UM) and Cleveland Clinic (CC), correlate preresection and final resection diagnosis, and identify histologic features in biopsies that might be predictive of adenocarcinoma on esophagectomy. A total of 112 cases with a consensus biopsy diagnosis (agreement by ≥4 of 7 gastrointestinal pathologists) were statistically analyzed to identify histologic features that predicted adenocarcinoma on resection. Applying the UM criteria to the biopsy series showed excellent agreement with the CC system (κ=0.86) and significant correlation between preoperative and esophagectomy diagnoses (P<0.001). The likelihood of finding carcinoma on resection was significantly higher with the category of HGD with marked glandular distortion cannot exclude intramucosal adenocarcinoma [CC; odd ratio (OR), 2.8; P=0.046] or HGD suspicious for adenocarcinoma (UM; OR, 4.3; P=0.008), compared to HGD alone. The presence of "never-ending" glands (OR, 3.7; P=0.008), sheet-like growth (P<0.001), angulated glands (OR, 8.5; P<0.001), ≥3 dilated glands with intraluminal debris (OR, 2.6; P=0.05), and >1 focus of single-cell infiltration into the lamina propria (OR, 8.9; P<0.001) increased the odds of finding carcinoma on resection. The latter 2 variables remained independent predictors of adenocarcinoma in multivariable analysis. In conclusion, the CC and UM systems show excellent agreement and define histologic categories that can improve prediction of adenocarcinoma on resection.

Protein kinase Czeta represses the interleukin-6 promoter and impairs tumorigenesis in vivo.

Gene alterations in tumor cells that confer the ability to grow under nutrient- and mitogen-deficient conditions constitute a competitive advantage that leads to more-aggressive forms of cancer. The atypical protein kinase C (PKC) isoform, PKCzeta, has been shown to interact with the signaling adapter p62, which is important for Ras-induced lung carcinogenesis. Here we show that PKCzeta-deficient mice display increased Ras-induced lung carcinogenesis, suggesting a new role for this kinase as a tumor suppressor in vivo. We also show that Ras-transformed PKCzeta-deficient lungs and embryo fibroblasts produced more interleukin-6 (IL-6), which we demonstrate here plays an essential role in the ability of Ras-transformed cells to grow under nutrient-deprived conditions in vitro and in a mouse xenograft system in vivo. We also show that PKCzeta represses histone acetylation at the C/EBPbeta element in the IL-6 promoter. Therefore, PKCzeta, by controlling the production of IL-6, is a critical signaling molecule in tumorigenesis.

Cyclooxygenase-2 (COX-2) expression by immunohistochemistry in glioblastoma multiforme.

Cyclooxygenase-2 (COX-2) (an enzyme responsible for the conversion of arachidonic acid to prostaglandin) upregulation has been described in association with a variety of tumors including gliomas. This study reviews the immunohistochemical profile of 47 glioblastoma multiforme using COX-2 antibody and correlates the results with MIB-1 (marker of cell proliferation) immunostaining. Positive staining with COX-2 was observed in 35 tumors (74.5%); more than 10% tumor cell positivity was seen in 10 tumors (21.3%). Immunostaining results were as follows: no staining, N = 12 (25.5%); 0% to 5% of tumor cells, N = 20 (42.6%); 5% to 10%, N = 5 (10.6%); 10% to 20%, N = 4 (8.5%); 20% to 50%, N = 4 (8.5%); and greater than 50%, N = 2 (4.3%). The mean MIB-1 labeling index for all tumors ranged from 3.0 to 76.4 (mean, 19.6). Mean MIB-1 labeling indices were higher in tumors with greater than 5% COX-2 immunostaining (mean MIB-1 labeling index, 23.5) versus tumors with 0% to 5% COX-2 immunostaining (mean MIB-1 labeling index, 17.7). There is evidence of COX-2 expression by immunohistochemistry in the majority of glioblastoma multiforme. As a group, tumors with a higher rate of cell proliferation tended to have increased expression of COX-2. These findings are significant in that therapeutic agents, which inhibit COX-2, are currently available and may play a role in the management of glioblastoma multiforme.