Neuropilin-2 is an independent prognostic factor for shorter cancer-specific survival in patients with acinar adenocarcinoma of the prostate.

Neuropilin-2 (NRP2) is a member of the neuropilin receptor family and known to regulate autophagy and mTORC2 signaling in prostate cancer (PCa). Our study investigated the association of immunohistochemical NRP2 expression with clinicopathological data in PCa patients. For this purpose, we generated a tissue microarray with prostate tissue specimens from 400 PCa patients treated by radical prostatectomy. We focused on patients with high-risk factors such as extraprostatic extension (pT ≥ 3), Gleason score ≥8 and/or the presence of regional lymph node metastases (pN1). Protein levels of NRP2, the vascular endothelial growth factor C (VEGFC) and oncogenic v-ets avian erythroblastosis virus E26 oncogene homolog (ERG) gene as an indicator for TMPRSS2-ERG fusion was assessed in relation to the patients' outcome. NRP2 emerged as an independent prognostic factor for cancer-specific survival (CSS) (hazard ratio 2.360, 95% confidence interval = 1.2-4.8; p = 0.016). Moreover, the association between NRP2 expression and shorter CSS was also especially pronounced in patients at high risk for progression (log-rank test: p = 0.010). We evaluated the association between NRP2 and the TMPRSS2-ERG gene fusion status assessed by immunohistochemical nuclear ERG staining. However, ERG staining alone did not show any prognostic significance. NRP2 immunostaining is significantly associated with shorter CSS in ERG-negative tumors (log-rank test: p = 0.012). No prognostic impact of NRP2 expression on CSS was observed in ERG-positive tumors (log-rank test: p = 0.153). Our study identifies NRP2 as an important prognostic marker for a worse clinical outcome especially in patients with a high-risk PCa and in patients with ERG-negative PCa.

Cellular organization and histogenesis of adenosquamous carcinoma of the pancreas: evidence supporting the squamous metaplasia concept.

Adenosquamous carcinoma of the pancreas (ASCAP) is characterized by conventional pancreatic ductal adenocarcinoma (PDAC) and squamous carcinoma components with at least 30% of the tumour showing squamous differentiation. To get further insight into the histogenesis of these lesions, we analysed the cellular organization of ASCAP compared to PDACs. Using Immunohistochemistry and triple immunofluorescence labelling studies for keratins, p63, p40, MUC1, MUC2, MUC5AC, Ki67, and EGFR we demonstrate that many ASCAPs contain a transitional zone between the K8/18-positive adenocarcinomatous component and the p63+ /p40+ /K5/K14+ squamous component initiated by the expression of p63 in K8/18+ adenocarcinomatous cells and the appearance of basally located p63+ K5/14+ cells. p63+ K5/14+ cells give rise to fully developed squamous differentiation. Notably, 25% of conventional PDACs without histologically recognizable squamous component contain foci of p63+ p40+ and K5/14+ cells similar to the transitional zone. Our data provide evidence that the squamous carcinoma components of ASCAPs originate from pre-existing PDAC via transdifferentiation of keratin K8/18-positive glandular cells to p63-, p40-, and keratin K5/14-positive squamous carcinoma cells supporting the squamous metaplasia hypothesis. Thus our findings provide new evidence about the cellular process behind squamous differentiation in ASCAPs.

Protein Paucimannosylation Is an Enriched N-Glycosylation Signature of Human Cancers.

While aberrant protein glycosylation is a recognized characteristic of human cancers, advances in glycoanalytics continue to discover new associations between glycoproteins and tumorigenesis. This glycomics-centric study investigates a possible link between protein paucimannosylation, an under-studied class of human N-glycosylation [Man1-3 GlcNAc2 Fuc0-1 ], and cancer. The paucimannosidic glycans (PMGs) of 34 cancer cell lines and 133 tissue samples spanning 11 cancer types and matching non-cancerous specimens are profiled from 467 published and unpublished PGC-LC-MS/MS N-glycome datasets collected over a decade. PMGs, particularly Man2-3 GlcNAc2 Fuc1 , are prominent features of 29 cancer cell lines, but the PMG level varies dramatically across and within the cancer types (1.0-50.2%). Analyses of paired (tumor/non-tumor) and stage-stratified tissues demonstrate that PMGs are significantly enriched in tumor tissues from several cancer types including liver cancer (p = 0.0033) and colorectal cancer (p = 0.0017) and is elevated as a result of prostate cancer and chronic lymphocytic leukaemia progression (p < 0.05). Surface expression of paucimannosidic epitopes is demonstrated on human glioblastoma cells using immunofluorescence while biosynthetic involvement of N-acetyl-ß-hexosaminidase is indicated by quantitative proteomics. This intriguing association between protein paucimannosylation and human cancers warrants further exploration to detail the biosynthesis, cellular location(s), protein carriers, and functions of paucimannosylation in tumorigenesis and metastasis.

Mitochondrial PIWI-interacting RNAs are novel biomarkers for clear cell renal cell carcinoma.

PURPOSE: PIWI-interacting RNAs (piRNAs) have been suggested to serve as biomarkers in cancer. In this study, we validated the expression profile of two piRNAs derived from mitochondria, piR-34536 and piR-51810, in tissue and serum of a cohort of clear cell renal cell carcinoma (ccRCC) patients. METHODS: Tissue and serum samples of patients with ccRCC were collected prospectively in our biobank. Total RNA was isolated from 118 ccRCC tissues, 75 normal renal tissues as well as 30 serum samples from patients with ccRCC, and 15 serum samples from patients with non-malignant diseases. The expression of piRNAs was determined using quantitative real-time PCR. RESULTS: Both piR-34536 and piR-51810 were downregulated in ccRCC compared to non-malignant renal tissue. Decreased tissue piRNA levels were significant and independent predictors of shortened progression-free, cancer-specific and overall survival of ccRCC patients. The piRNA levels in serum did not differ in ccRCC patients and control subjects. CONCLUSIONS: The expression of piR-34536 and piR-51810 in ccRCC tissues may be used as prognostic biomarkers in ccRCC.

Sex-specific differences in age-dependent progression of aortic dysfunction and related cardiac remodeling in spontaneously hypertensive rats.

Evidence of sex-specific differences in renin-angiotensin-system (RAS) and arterial pressure has been shown in many mammals, including spontaneously hypertensive rats (SHRs). Although SHRs have been used extensively as a leading experimental model of hypertension, the effects of sex-specific differences in RAS on aortic function and related cardiac remodeling during aging and hypertension have not been documented in detail. We examined structural and functional changes in aorta and heart of female and male SHRs at the ages of 5, 14, 29, and 36 wk. SHRs of both sexes were hypertensive from 14 wk. Aortic endothelial dysfunction and fibrosis, left ventricular (LV) hypertrophy, and cardiac fibrosis were evident at the age of 29 wk in male SHRs but first appeared only at the age of 36 wk in female SHRs. There was a pronounced delay of matrix metalloproteinase-2 activity in the aorta and heart of female SHRs, which was associated with preservation of 40% more elastin and less extensive cardiac fibrosis than in males. At 5, 29, and 36 wk of age, female SHRs showed higher levels of aortic and myocardial AT2R and MasR mRNA and decreased ANG II-mediated aortic constriction. Although female SHRs had increased relaxation to AT2R stimulation at 5 and 29 wk compared with males, this difference disappeared at 36 wk of age. This study documents sex-specific differences in the temporal progression of aortic dysfunction and LV hypertrophy in SHRs, which are independent of arterial pressure and are apparently mediated by higher AT2R expression in the heart and aorta of female SHRs.

A role for cancer stem cells in therapy resistance: cellular and molecular mechanisms.

Similar to normal tissue, many tumors have a hierarchical organization where tumorigenic cancer stem cells (CSCs) differentiate into non-tumorigenic progenies. A host of studies have demonstrated that although CSCs and their non-tumorigenic progenies within the same clone can share common genotype, they display different epigenetic profiles that results in changes of multiple signaling pathways. Many of these pathways confer cell adaptation to the microenvironmental stresses including inflammation, hypoxia, low pH, shortage in nutrients and anti-cancer therapies. Treatment strategies based on combination of conventional therapies targeting bulk tumor cells and CSC-specific pathway inhibition bear a promise to improve cancer cure compared to monotherapies. In this review we describe the mechanisms of CSC-related therapy resistance including drug efflux by ABC transporters, activation of aldehyde dehydrogenase and developmental pathways, enhanced DNA damage response, autophagy and microenvironmental conditions, and discuss possible therapeutic strategies for improving cancer treatment.

Soy isoflavone exposure through all life stages accelerates 17ß-estradiol-induced mammary tumor onset and growth, yet reduces tumor burden, in ACI rats.

There is an ongoing debate whether the intake of soy-derived isoflavones (sISO) mediates beneficial or adverse effects with regard to breast cancer risk. Therefore, we investigated whether nutritional exposure to a sISO-enriched diet from conception until adulthood impacts on 17ß-estradiol (E2)-induced carcinogenesis in the rat mammary gland (MG). August-Copenhagen-Irish (ACI) rats were exposed to dietary sISO from conception until postnatal day 285. Silastic tubes containing E2 were used to induce MG tumorigenesis. Body weight, food intake, and tumor growth were recorded weekly. At necropsy, the number, position, size, and weight of each tumor were determined. Plasma samples underwent sISO analysis, and the morphology of MG was analyzed. Tumor incidence and multiplicity were reduced by 20 and 56 %, respectively, in the sISO-exposed rats compared to the control rats. Time-to-tumor onset was shortened from 25 to 20 weeks, and larger tumors developed in the sISO-exposed rats. The histological phenotype of the MG tumors was independent of the sISO diet received, and it included both comedo and cribriform phenotypes. Morphological analyses of the whole-mounted MGs also showed no diet-dependent differences. Lifelong exposure to sISO reduced the overall incidence of MG carcinomas in ACI rats, although the time-to-tumor was significantly shortened.

Dual role of B7 costimulation in obesity-related nonalcoholic steatohepatitis and metabolic dysregulation.

UNLABELLED: The low-grade inflammatory state present in obesity contributes to obesity-related metabolic dysregulation, including nonalcoholic steatohepatitis (NASH) and insulin resistance. Intercellular interactions between immune cells or between immune cells and hepatic parenchymal cells contribute to the exacerbation of liver inflammation and steatosis in obesity. The costimulatory molecules, B7.1 and B7.2, are important regulators of cell-cell interactions in several immune processes; however, the role of B7 costimulation in obesity-related liver inflammation is unknown. Here, diet-induced obesity (DIO) studies in mice with genetic inactivation of both B7.1 and B7.2 (double knockout; DKO) revealed aggravated obesity-related metabolic dysregulation, reduced insulin signalling in the liver and adipose tissue (AT), glucose intolerance, and enhanced progression to steatohepatitis resulting from B7.1/B7.2 double deficiency. The metabolic phenotype of B7.1/B7.2 double deficiency upon DIO was accompanied by increased hepatic and AT inflammation, associated with largely reduced numbers of regulatory T cells (Tregs) in these organs. In order to assess the role of B7 costimulation in DIO in a non-Treg-lacking environment, we performed antibody (Ab)-mediated inhibition of B7 molecules in wild-type mice in DIO. Antibody-blockade of both B7.1 and B7.2 improved the metabolic phenotype of DIO mice, which was linked to amelioration of hepatic steatosis and reduced inflammation in liver and AT. CONCLUSION: Our study demonstrates a dual role of B7 costimulation in the course of obesity-related sequelae, particularly NASH. The genetic inactivation of B7.1/B7.2 deteriorates obesity-related liver steatosis and metabolic dysregulation, likely a result of the intrinsic absence of Tregs in these mice, rendering DKO mice a novel murine model of NASH. In contrast, inhibition of B7 costimulation under conditions where Tregs are present may provide a novel therapeutic approach for obesity-related metabolic dysregulation and, especially, NASH.

The histone demethylase UTX regulates stem cell migration and hematopoiesis.

Regulated migration of hematopoietic stem cells is fundamental for hematopoiesis. The molecular mechanisms underlying stem cell trafficking are poorly defined. Based on a short hairpin RNA library and stromal cell-derived factor-1 (SDF-1) migration screening assay, we identified the histone 3 lysine 27 demethylase UTX (Kdm6a) as a novel regulator for hematopoietic cell migration. Using hematopoietic stem and progenitor cells from our conditional UTX knockout (KO) mice, we were able to confirm the regulatory function of UTX on cell migration. Moreover, adult female conditional UTX KO mice displayed myelodysplasia and splenic erythropoiesis, whereas UTX KO males showed no phenotype. During development, all UTX KO female and a portion of UTX KO male embryos developed a cardiac defect, cranioschisis, and died in utero. Therefore, UTY, the male homolog of UTX, can compensate for UTX in adults and partially during development. Additionally, we found that UTX knockdown in zebrafish significantly impairs SDF-1/CXCR4-dependent migration of primordial germ cells. Our data suggest that UTX is a critical regulator for stem cell migration and hematopoiesis.

HIF-1α is a protective factor in conditional PHD2-deficient mice suffering from severe HIF-2α-induced excessive erythropoiesis.

Erythropoiesis must be tightly balanced to guarantee adequate oxygen delivery to all tissues in the body. This process relies predominantly on the hormone erythropoietin (EPO) and its transcription factor hypoxia inducible factor (HIF). Accumulating evidence suggests that oxygen-sensitive prolyl hydroxylases (PHDs) are important regulators of this entire system. Here, we describe a novel mouse line with conditional PHD2 inactivation (cKO P2) in renal EPO producing cells, neurons, and astrocytes that displayed excessive erythrocytosis because of severe overproduction of EPO, exclusively driven by HIF-2α. In contrast, HIF-1α served as a protective factor, ensuring survival of cKO P2 mice with HCT values up to 86%. Using different genetic approaches, we show that simultaneous inactivation of PHD2 and HIF-1α resulted in a drastic PHD3 reduction with consequent overexpression of HIF-2α-related genes, neurodegeneration, and lethality. Taken together, our results demonstrate for the first time that conditional loss of PHD2 in mice leads to HIF-2α-dependent erythrocytosis, whereas HIF-1α protects these mice, providing a platform for developing new treatments of EPO-related disorders, such as anemia.

Dickkopf-1 is regulated by the mevalonate pathway in breast cancer.

INTRODUCTION: Amino-bisphosphonates and statins inhibit the mevalonate pathway, and may exert anti-tumor effects. The Wnt inhibitor dickkopf-1 (DKK-1) promotes osteolytic bone lesions by inhibiting osteoblast functions and has been implicated as an adverse marker in multiple cancers. We assessed the effects of mevalonate pathway inhibition on DKK-1 expression in osteotropic breast cancer. METHODS: Regulation of DKK-1 by bisphosphonates and statins was assessed in human breast cancer cell lines, and the role of the mevalonate pathway and downstream targets was analyzed. Moreover, the potential of breast cancer cells to modulate osteoblastogenesis via DKK-1 was studied in mC2C12 cells. Clinical relevance was validated by analyzing DKK-1 expression in the tissue and serum of women with breast cancer exposed to bisphosphonates. RESULTS: DKK-1 was highly expressed in receptor-negative breast cancer cell lines. Patients with receptor-negative tumors displayed elevated levels of DKK-1 at the tissue and serum level compared to healthy controls. Zoledronic acid and atorvastatin potently suppressed DKK-1 in vitro by inhibiting geranylgeranylation of CDC42 and Rho. Regulation of DKK-1 was strongest in osteolytic breast cancer cell lines with abundant DKK-1 expression. Suppression of DKK-1 inhibited the ability of breast cancer cells to block WNT3A-induced production of alkaline phosphates and bone-protective osteoprotegerin in preosteoblastic C2C12 cells. In line with the in vitro data, treatment of breast cancer patients with zoledronic acid decreased DKK-1 levels by a mean of 60% after 12 months of treatment. CONCLUSION: DKK-1 is a novel target of the mevalonate pathway that is suppressed by zoledronic acid and atorvastatin in breast cancer.

High serum levels of Dickkopf-1 are associated with a poor prognosis in prostate cancer patients.

BACKGROUND: The Wnt inhibitor Dickkopf-1 (DKK-1) has been linked to the progression of malignant bone disease by impairing osteoblast activity. In addition, there is increasing data to suggest direct tumor promoting effects of DKK-1. The prognostic role of DKK-1 expression in prostate cancer remains unclear. METHODS: A prostate cancer tissue microarray (n = 400) was stained for DKK-1 and DKK-1 serum levels were measured in 80 patients with prostate cancer. The independent prognostic value of DKK-1 expression was assessed using multivariate analyses. RESULTS: DKK-1 tissue expression was significantly increased in prostate cancer compared to benign disease, but was not correlated with survival. However, high DKK-1 serum levels at the time of the diagnosis were associated with a significantly shorter overall and disease-specific survival. Multivariate analyses defined high serum levels of DKK-1 as an independent prognostic marker in prostate cancer (HR 3.73; 95%CI 1.44-9.66, p = 0.007). CONCLUSION: High DKK-1 serum levels are associated with a poor survival in patients with prostate cancer. In light of current clinical trials evaluating the efficacy of anti-DKK-1 antibody therapies in multiple myeloma and solid malignancies, the measurement of DKK-1 in prostate cancer may gain clinical relevance.

Understanding the molecular regulators of neuroendocrine prostate cancer.

Worldwide, prostate cancer (PCa) remains a leading cause of death in men. Histologically, the majority of PCa cases are classified as adenocarcinomas, which are mainly composed of androgen receptor-positive luminal cells. PCa is initially driven by the androgen receptor axis, where androgen-mediated activation of the receptor is one of the primary culprits for disease progression. Therefore, in advanced stage PCa, patients are generally treated with androgen deprivation therapies alone or in combination with androgen receptor pathway inhibitors. However, after an initial decrease, the cancer recurs for majority patients. At this stage, cancer is known as castration-resistant prostate cancer (CRPC). Majority of CRPC tumors still depend on androgen receptor axis for its progression to metastasis. However, in around 20-30% of cases, CRPC progresses via an androgen receptor-independent pathway and is often presented as neuroendocrine cancer (NE). This NE phenotype is highly aggressive with poor overall survival as compared to CRPC adenocarcinoma. NE cancers are resistant to standard taxane chemotherapies, which are often used to treat metastatic disease. Pathologically and morphologically, NE cancers are highly diverse and often co-exist with adenocarcinoma. Due to the lack of proper biomarkers, it is often difficult to make an early diagnosis of this lethal disease. Moreover, increased tumor heterogeneity and admixtures of adeno and NE subtypes in the same tumor make early detection of NE tumors very difficult. With the advancement of our knowledge and sequencing technology, we are now able to better understand the molecular mediators of this transformation pathway. This current study will give an update on how various molecular regulators are involved in these lineage transformation processes and what challenges we are still facing to detect and treat this cancer.

Neuropilin2 in Mesenchymal Stromal Cells as a Potential Novel Therapeutic Target in Myelofibrosis.

Bone marrow fibrosis in myeloproliferative neoplasm (MPN), myelodysplastic syndromes (MDS), MPN/MDS overlap syndromes and acute myeloid leukemia (AML) is associated with poor prognosis and early treatment failure. Myelofibrosis (MF) is accompanied by reprogramming of multipotent bone marrow mesenchymal stromal cells (MSC) into osteoid and fiber-producing stromal cells. We demonstrate NRP2 and osteolineage marker NCAM1 (neural cell adhesion molecule 1) expression within the endosteal niche in normal bone marrow and aberrantly in MPN, MDS MPN/MDS overlap syndromes and AML (n = 99), as assessed by immunohistochemistry. Increased and diffuse expression in mesenchymal stromal cells and osteoblasts correlates with high MF grade in MPN (p < 0.05 for NRP2 and NCAM1). Single cell RNA sequencing (scRNAseq) re-analysis demonstrated NRP2 expression in endothelial cells and partial co-expression of NRP2 and NCAM1 in normal MSC and osteoblasts. Potential ligands included transforming growth factor ß1 (TGFB1) from osteoblasts and megakaryocytes. Murine ThPO and JAK2V617F myelofibrosis models showed co-expression of Nrp2 and Ncam1 in osteolineage cells, while fibrosis-promoting MSC only express Nrp2. In vitro experiments with MC3T3-E1 pre-osteoblasts and analysis of Nrp2-/- mouse femurs suggest that Nrp2 is functionally involved in osteogenesis. In summary, NRP2 represents a potential novel druggable target in patients with myelofibrosis.

Efzofitimod: a novel anti-inflammatory agent for sarcoidosis.

Efzofitimod is a first-in-class biologic based on a naturally occurring splice variant of histidyl-tRNA synthetase (HARS) that downregulates immune responses via selective modulation of neuropilin-2 (NRP2). Preclinical data found high expression of NRP2 in sarcoidosis granulomas. Treatment with efzofitimod reduced the granulomatous inflammation induced by P. acnes in an animal model of sarcoidosis. A dose escalating trial of efzofitimod in sarcoidosis with chronic symptomatic pulmonary disease found that treatment with efzofitimod was associated with improved quality of life with a trend towards reduced glucocorticoid use and stable to improved pulmonary function. These studies have led to a large Phase 3 trial of efzofitimod in symptomatic pulmonary sarcoidosis.

Development and Characterization of a Novel Neuropilin-2 Antibody for Immunohistochemical Staining of Cancer and Sarcoidosis Tissue Samples.

Neuropilin-2 (NRP2) is a cell surface receptor that plays key roles in lymphangiogenesis, but also in pathophysiological conditions such as cancer and inflammation. NRP2 targeting by efzofitimod, a novel immunomodulatory molecule, is currently being tested for the treatment of pulmonary sarcoidosis. To date, no anti-NRP2 antibodies are available for companion diagnostics. Here we describe the development and characterization of a novel NRP2 antibody. Using a variety of research techniques, that is, enzyme-linked immunoassay, Western blot, biolayer interferometry, and immunohistochemistry, we demonstrate that our antibody detects all major NRP2 isoforms and does not cross-react with NRP1. Using this antibody, we show high NRP2 expression in granulomas from sarcoidosis patient skin and lung biopsies. Our novel anti-NRP2 antibody could prove to be a useful clinical tool for sarcoidosis and other indications where NRP2 has been implicated. Clinical Trial Registration: clinicaltrials.gov NCT05415137.

Understanding the role of Pax5 in development of taxane-resistant neuroendocrine like prostate cancers.

Resistance to the current Androgen Receptor Signaling Inhibitor (ARSI) therapies has led to higher incidences of therapy-induced neuroendocrine-like prostate cancer (t-NEPC). This highly aggressive subtype with predominant small cell-like characteristics is resistant to taxane chemotherapies and has a dismal overall survival. t-NEPCs are mostly treated with platinum-based drugs with a combination of etoposide or taxane and have less selectivity and high systemic toxicity, which often limit their clinical potential. During t-NEPC transformation, adenocarcinomas lose their luminal features and adopt neuro-basal characteristics. Whether the adaptive neuronal characteristics of t-NEPC are responsible for such taxane resistance remains unknown. Pathway analysis from patient gene-expression databases indicates that t-NEPC upregulates various neuronal pathways associated with enhanced cellular networks. To identify transcription factor(s) (TF) that could be important for promoting the gene expression for neuronal characters in t-NEPC, we performed ATAC-Seq, acetylated-histone ChIP-seq, and RNA-seq in our NE-like cell line models and analyzed the promoters of transcriptionally active and significantly enriched neuroendocrine-like (NE-like) cancer-specific genes. Our results indicate that Pax5 could be an important transcription factor for neuronal gene expression and specific to t-NEPC. Pathway analysis revealed that Pax5 expression is involved in axonal guidance, neurotransmitter regulation, and neuronal adhesion, which are critical for strong cellular communications. Further results suggest that depletion of Pax5 disrupts cellular interaction in NE-like cells and reduces surface growth factor receptor activation, thereby, sensitizing them to taxane therapies. Moreover, t-NEPC specific hydroxymethylation of Pax5 promoter CpG islands favors Pbx1 binding to induce Pax5 expression. Based on our study, we concluded that continuous exposure to ARSI therapies leads to epigenetic modifications and Pax5 activation in t-NEPC, which promotes the expression of genes necessary to adopt taxane-resistant NE-like cancer. Thus, targeting the Pax5 axis can be beneficial for reverting their taxane sensitivity.

Identification of Epigenetically Regulated Genes Distinguishing Intracranial from Extracranial Melanoma Metastases.

Despite remarkable advances in treating patients with metastatic melanoma, the management of melanoma brain metastases remains challenging. Recent evidence suggests that epigenetic reprogramming is an important mechanism for the adaptation of melanoma cells to the brain environment. In this study, the methylomes and transcriptomes of a cohort of matched melanoma metastases were evaluated by integrated omics data analysis. The identified 38 candidate genes displayed distinct promoter methylation and corresponding gene expression changes in intracranial compared with extracranial metastases. The 11 most promising genes were validated on protein level in both tumor and surrounding normal tissue using immunohistochemistry. In accordance with the underlying promoter methylation and gene expression changes, a significantly different protein expression was confirmed for STK10, PDXK, WDR24, CSSP1, NMB, RASL11B, phosphorylated PRKCZ, PRKCZ, and phosphorylated GRB10 in the intracranial metastases. The observed changes imply a distinct intracranial phenotype with increased protein kinase B phosphorylation and a higher frequency of proliferating cells. Knockdown of PRKCZ or GRB10 altered the expression of phosphorylated protein kinase B and decreased the viability of a brain-specific melanoma cell line. In summary, epigenetically regulated cancer-relevant alterations were identified that provide insights into the molecular mechanisms that discriminate brain metastases from other organ metastases, which could be exploited by targeting the affected signaling pathways.

Inactivation of Brca2 promotes Trp53-associated but inhibits KrasG12D-dependent pancreatic cancer development in mice.

BACKGROUND & AIMS: Inherited mutations in the BRCA2 tumor suppressor have been associated with an increased risk of pancreatic cancer. To establish the contribution of Brca2 to pancreatic cancer we developed a mouse model of pancreas-specific Brca2 inactivation. Because BRCA2-inactivating mutations cause defects in repair of DNA double-strand breaks that result in chromosomal instability, we evaluated whether Brca2 inactivation induced instability in pancreatic tissue from these mice and whether associated pancreatic tumors were hypersensitive to DNA damaging agents. METHODS: We developed mouse models that combined pancreas-specific Kras activation and Trp53 deletion with Brca2 inactivation. Development of pancreatic cancer was assessed; tumors and nonmalignant tissues were analyzed for chromosomal instability and apoptosis. Cancer cell lines were evaluated for sensitivity to DNA damaging agents. RESULTS: In the presence of disrupted Trp53, Brca2 inactivation promoted the development of premalignant lesions and pancreatic tumors that reflected the histology of human disease. Cancer cell lines derived from these tumors were hypersensitive to specific DNA damaging agents. In contrast, in the presence of KrasG12D, Brca2 inactivation promoted chromosomal instability and apoptosis and unexpectedly inhibited growth of premalignant lesions and tumors. CONCLUSIONS: Trp53 signaling must be modified before inactivation of the Brca2 wild-type allele, irrespective of Kras status, for Brca2-deficient cells to form tumors.

The Role of Perineural Invasion in Prostate Cancer and Its Prognostic Significance.

Perineural invasion (PNI) is a common indication of tumor metastasis that can be detected in multiple malignancies, including prostate cancer. In the development of PNI, tumor cells closely interact with the nerve components in the tumor microenvironment and create the perineural niche, which provides a supportive surrounding for their survival and invasion and benefits the nerve cells. Various transcription factors, cytokines, chemokines, and their related signaling pathways have been reported to be important in the progress of PNI. Nevertheless, the current understanding of the molecular mechanism of PNI is still very limited. Clinically, PNI is commonly associated with adverse clinicopathological parameters and poor outcomes for prostate cancer patients. However, whether PNI could act as an independent prognostic predictor remains controversial among studies due to inconsistent research aim and endpoint, sample type, statistical methods, and, most importantly, the definition and inclusion criteria. In this review, we provide a summary and comparison of the prognostic significance of PNI in prostate cancer based on existing literature and propose that a more standardized description of PNI would be helpful for a better understanding of its clinical relevance.