Expression of HNF-1α and HNF-1β in various histological differentiations of hepatocellular carcinoma

Hepatic nuclear factor 1 (HNF-1) regulates genes in a hepatocyte-specific manner. It has been previously reported that the ratio of HNF-1α and HNF-1β mRNA is related to histological differentiation hepatocellular carcinoma (HCC). In this study, the expression levels of the HNF-1α and HNF-1β proteins were analysed relatively and quantitatively in various histologically differentiated HCC and surrounding non-cancerous tissues, and HNF-1α binding activity for the AT element of the B domain of the human α-fetoprotein enhancer was examined. Western blot analysis demonstrated that HNF-1α protein was expressed at a higher level in well-differentiated HCC tissues than in the surrounding non-HCC tissues; on the other hand, the HNF-1α protein was expressed at lower levels in moderately and poorly differentiated HCCs than in the surrounding non-HCC tissues. The levels of HNF-1β expression in well-differentiated and poorly differentiated HCCs were similar to and higher than those found in the respective surrounding non-cancerous portions. In binding assays, HNF-1 binding activity was high in well-differentiated HCC and lower in moderately and poorly differentiated HCCs. Most well-differentiated HCC cases showed immunohistochemical expression of HNF-1α. These findings show that poor histological differentiation of HCC correlates with decreases in the level and activity of HNF-1α proteins. © 1998 John Wiley & Sons, Ltd.     

Emerging entities in NUTM1‐rearranged neoplasms

Structural alterations of NUTM1 were originally thought to be restricted to poorly differentiated carcinomas with variable squamous differentiation originating in the midline organs of children and adolescents. Termed NUT carcinomas (NCs), they were defined by a t(15;19) chromosomal rearrangement that was found to result in a BRD4‐NUTM1 gene fusion. However, the use of DNA and RNA‐based next‐generation sequencing has recently revealed a multitude of new NUTM1 fusion partners in a diverse array of neoplasms including sarcoma‐like tumors, poromas, and acute lymphoblastic leukemias (ALLs) that we propose to call NUTM1‐rearranged neoplasms (NRNs). Intriguingly, the nosology of NRNs often correlates with the functional classification of the fusion partner, suggesting different oncogenic mechanisms within each NRN division. Indeed, whereas NCs are characterized by their aggressiveness and intransigence to standard therapeutic measures, the more positive clinical outcomes seen in some sarcoma and ALL NRNs may reflect these mechanistic differences. Here we provide a broad overview of the molecular, nosological, and clinical features in these newly discovered neoplastic entities. We describe how aberrant expression of NUTM1 due to fusion with an N‐terminal DNA/chromatin‐binding protein can generate a potentially powerful chromatin modifier that can give rise to oncogenic transformation in numerous cellular contexts. We also conclude that classification, clinical behavior, and therapeutic options may be best defined by the NUTM1 fusion partner rather than by tumor morphology or immunohistochemical profile.     

Overexpression of PGC1α and accumulation of p62 in apocrine carcinoma of the breast

Apocrine carcinoma is categorized as a special type of breast carcinoma because of its specific morphological features. To clarify the characteristics of apocrine carcinoma from the point of view of the mitochondrial profile, we conducted a comparative study between apocrine and non‐apocrine carcinomas. The expressions of mitochondrial related factors (PGC1α, Nrf1, Nrf2, mtTFA and COX4) were examined in a testing set of breast cancer tissue. Apocrine carcinomas showed a clear tendency towards higher mRNA expression levels of PGC1α than non‐apocrine carcinomas. The expression of the selected factor, PGC1α, as well as that of p62 was further examined. The results revealed that apocrine carcinomas showed a higher immunohistochemical positivity rate for PGC1α (21.3% vs. 3.2%; P = 0.008), and that the mRNA expression level of PGC1α was significantly higher in apocrine carcinoma than in non‐apocrine carcinoma (P = 0.007). The immunohistochemical positivity rate for p62 protein was also higher in apocrine carcinomas (44.7% vs. 21.0%; P = 0.015), although no significant difference in the p62 mRNA expression level was detected between the two types of carcinoma (P = 0.633). In conclusion, this study revealed that apocrine carcinoma overexpressed PGC1α contributing to mitochondrial biogenesis, and also p62 protein accumulation.     

Genotoxicity of 1‐methylpyrene and 1‐hydroxymethylpyrene in chinese hamster V79‐derived cells expressing both human CYP2E1 and SULT1A1

1‐Methylpyrene (1‐MP) is a widespread pollutant that is carcinogenic in animals following metabolic activation. Previous studies have shown that benzylic hydroxylation of 1‐MP, catalyzed by multiple CYP isoforms, gives rise to 1‐hydroxymethylpyrene (1‐HMP), which becomes bioreactive following further metabolism by various sulfotransferase (SULT) isoforms. However, the mutagenic and chromosome damaging effects of 1‐MP and 1‐HMP in mammalian cells have not been investigated. In this study a Chinese hamster V79‐derived cell line expressing both human CYP2E1 and human SULT1A1 was used to investigate the ability of 1‐MP and 1‐HMP to induce cytotoxicity (using the CCK‐8 assay), micronuclei and Hprt gene mutations. The role of each enzyme was investigated through co‐exposure in the presence of an enzyme inhibitor. We found that at concentrations of 0.5–4 μM and 5–20 μM, under conditions where no reduction in cell viability/growth occurred, 1‐HMP and 1‐MP induced micronuclei in V79‐hCYP2E1‐hSULT1A1 cells in a concentration‐dependent manner; however, both compounds were inactive in V79 cells. Similarly, they both caused an increase in Hprt mutant frequency in V79‐hCYP2E1‐hSULT1A1 cells in these concentration ranges, with 1‐MP impairing cell viability/growth at 10 μM and above in the mutagenicity assay. The compounds were again both inactive in V79 cells. The effects of 1‐HMP in V79‐hCYP2E1‐hSULT1A1 cells were blocked or reduced by addition of pentachlorophenol (PCP), a SULT1 inhibitor; the genotoxicity of 1‐MP was significantly reduced by either 1‐aminobenotrazole, a CYP2E1 inhibitor, or PCP. The results suggest that human CYP2E1 and SULT1A1 cooperate to activate 1‐MP and cause genotoxicity in mammalian cells. Environ. Mol. Mutagen. 56:404–411, 2015. © 2014 Wiley Periodicals, Inc.     

Activation of sterol regulatory element‐binding protein 1 (SREBP1)‐mediated lipogenesis by the Epstein–Barr virus‐encoded latent membrane protein 1 (LMP1) promotes cell proliferation and progression of nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is closely associated with Epstein–Barr virus (EBV) infection. The EBV‐encoded latent membrane protein 1 (LMP1), which is commonly expressed in NPC, engages multiple signaling pathways that promote cell growth, transformation, and metabolic reprogramming. Here, we report a novel function of LMP1 in promoting de novo lipogenesis. LMP1 increases the expression, maturation and activation of sterol regulatory element‐binding protein 1 (SREBP1), a master regulator of lipogenesis, and its downstream target fatty acid synthase (FASN). LMP1 also induces de novo lipid synthesis and lipid droplet formation. In contrast, small interfering RNA (siRNA) knockdown of LMP1 in EBV‐infected epithelial cells diminished SREBP1 activation and lipid biosynthesis. Furthermore, inhibition of the mammalian target of rapamycin (mTOR) pathway, through the use of either mTOR inhibitors or siRNAs, significantly reduced LMP1‐mediated SREBP1 activity and lipogenesis, indicating that LMP1 activation of the mTOR pathway is required for SREBP1‐mediated lipogenesis. In primary NPC tumors, FASN overexpression is common, with high levels correlating significantly with LMP1 expression. Moreover, elevated FASN expression was associated with aggressive disease and poor survival in NPC patients. Luteolin and fatostatin, two inhibitors of lipogenesis, suppressed lipogenesis and proliferation of nasopharyngeal epithelial cells, effects that were more profound in cells expressing LMP1. Luteolin and fatostatin also dramatically inhibited NPC tumor growth in vitro and in vivo. Our findings demonstrate that LMP1 activation of SREBP1‐mediated lipogenesis promotes tumor cell growth and is involved in EBV‐driven NPC pathogenesis. Our results also reveal the therapeutic potential of utilizing lipogenesis inhibitors in the treatment of locally advanced or metastatic NPC. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.     

Inhibition of the LKB1–AMPK pathway by the Epstein–Barr virus‐encoded LMP1 promotes proliferation and transformation of human nasopharyngeal epithelial cells

The association of Epstein–Barr virus (EBV) infection with the development of nasopharyngeal carcinoma (NPC) is well established. Latent membrane protein 1 (LMP1), the major oncogene encoded by EBV, is believed to play a crucial role in NPC pathogenesis by virtue of its ability to constitutively activate multiple cell signalling pathways. The LKB1–AMPK pathway is a master regulator of cellular metabolism that, via modulation of energy metabolism, has tumour suppressor activity. In this study we identify a novel ability of LMP1 to inhibit the LKB1–AMPK pathway through phosphorylation of LKB1 at serine 428 with subsequent suppression of the phosphorylation of AMPK and its substrates, ACC and Raptor. We show that MEK/ERK–MAPK signalling, activated by the CTAR1 domain of LMP1, is responsible for LKB1–AMPK inactivation. In addition, reactivation of AMPK signalling by AMPK activator, AICAR, abolished LMP1‐induced cellular transformation (proliferation and anchorage‐independent growth) in nasopharyngeal epithelial cells. Immunohistochemical staining revealed that a low level of phosphorylated AMPK is common in primary NPC specimens, and that this correlated significantly with the expression of LMP1. AICAR treatment inhibited the proliferation and anchorage‐independent growth of NPC cells as well as potentiating the cytotoxic effect of the chemotherapeutic drug 5‐fluorouracil. The current findings demonstrate that LMP1‐mediated AMPK inactivation contributes to the proliferation and transformation of epithelial cells, thereby implicating the LKB1–AMPK pathway in the EBV‐driven pathogenesis of NPC. Our findings also suggest that AMPK activators could be used to enhance the efficacy of conventional chemotherapeutic agents in the treatment of local and metastatic NPC. Copyright © 2013 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Pannexin‐1‐dependent caspase‐1 activation and secretion of IL‐1β is regulated by zinc

Inflammatory processes induced by IL‐1β are critical for host defence responses, but are also implicated in disease. Zinc deficiency is a common consequence of, or contributor to, human inflammatory disease. However, the molecular mechanisms through which zinc contributes to inflammatory disease remain largely unknown. We report here that zinc metabolism regulates caspase‐1 activation and IL‐1β secretion. One of the endogenous mediators of IL‐1β secretion is adenosine triphosphate, acting via the P2X7‐receptor and caspase‐1 activation in cells primed with an inflammatory stimulus such as LPS. We show that this process is selectively abolished by a brief pre‐treatment with the zinc chelator N,N,N′,N′‐tetrakis‐(2‐pyridylmethyl) ethylene diamine (TPEN). These effects on IL‐1β secretion were independent of rapid changes in free zinc within the cell, not a direct effect on caspase‐1 activity, and upstream of caspase‐1 activation. TPEN did however inhibit the activity of pannexin‐1, a hemi‐channel critical for adenosine triphosphate and nigericin‐induced IL‐1β release. These data provide new insights into the mechanisms of caspase‐1 activation and how zinc metabolism contributes to inflammatory mechanisms.     

Three‐dimensional ultrashort echo time cones T1ρ (3D UTE‐cones‐T1ρ) imaging

We report a novel three‐dimensional (3D) ultrashort echo time (UTE) sequence employing Cones trajectory and T_1ρ preparation (UTE‐Cones‐T_1ρ) for quantitative T_1ρ assessment of short T₂ tissues in the musculoskeletal system. A basic 3D UTE‐Cones sequence was combined with a spin‐locking preparation pulse for T_1ρ contrast. A relatively short TR was used to decrease the scan time, which required T₁ measurement and compensation using 3D UTE‐Cones data acquisitions with variable TRs. Another strategy to reduce the total scan time was to acquire multiple Cones spokes (N_sp) after each T_1ρ preparation and fat saturation. Four spin‐locking times (TSL = 0–20 ms) were acquired over 12 min, plus another 7 min for T₁ measurement. The 3D UTE‐Cones‐T_1ρ sequence was compared with a two‐dimensional (2D) spiral‐T_1ρ sequence for the imaging of a spherical CuSO₄ phantom and ex vivo meniscus and tendon specimens, as well as the knee and ankle joints of healthy volunteers, using a clinical 3‐T scanner. The CuSO₄ phantom showed a T_1ρ value of 76.5 ± 1.6 ms with the 2D spiral‐T_1ρ sequence, as well as 85.7 ± 3.6 and 89.2 ± 1.4 ms for the 3D UTE‐Cones‐T_1ρ sequences with N_sp of 1 and 5, respectively. The 3D UTE‐Cones‐T_1ρ sequence provided shorter T_1ρ values for the bovine meniscus sample relative to the 2D spiral‐T_1ρ sequence (10–12 ms versus 16 ms, respectively). The cadaveric human Achilles tendon sample could only be imaged with the 3D UTE‐Cones‐T_1ρ sequence (T_1ρ = 4.0 ± 0.9 ms), with the 2D spiral‐T_1ρ sequence demonstrating near‐zero signal intensity. Human studies yielded T_1ρ values of 36.1 ± 2.9, 18.3 ± 3.9 and 3.1 ± 0.4 ms for articular cartilage, meniscus and the Achilles tendon, respectively. The 3D UTE‐Cones‐T_1ρ sequence allows volumetric T_1ρ measurement of short T₂ tissues in vivo.     

α-Fetoprotein producing gastric carcinomas: A comparative study of three different subtypes

Nine cases of gastric carcinoma with excessive production of α-fetoprotein (AFP) were analyzed morphologically, histochemically and biochemically. Consequently, it was proposed that AFP-producing gastric carcinomas should be divided into three subtypes: (i) hepatoid type; (ii) yolk sac tumor-like type; and (iii) fetal gastrointestinal type. The data from the study suggested that the hepatoid type and the yolk sac tumor-like type are derived from liver cell metaplasia and yolk sac cell metaplasia of common poorly differentiated medullary adenocarcinoma, respectively. The fetal gastrointestinal type seemed to be a result of the imitation of fetal gastrointestinal epithelium by common tubular adenocarcinoma. The hepatoid type was also the most common in the file of AFP-producing gastric carcinoma. Unfortunately, most of the hepatoid types seemed to be highly malignant.     

Vitexin alleviates interleukin‐1β‐induced inflammatory responses in chondrocytes from osteoarthritis patients: Involvement of HIF‐1α pathway

It has been reported that vitexin has anti‐inflammatory effects in osteoarthritis (OA) rats. However, the effects of vitexin on interleukins‐1β (IL‐1β)‐stimulated OA patient‐derived chondrocytes have not been reported. The purpose of this study was to investigate the anti‐inflammatory effects of vitexin on IL‐1β‐stimulated human osteoarthritis chondrocytes and to reveal the involvement of hypoxia‐inducible factor 1α (HIF‐1α) pathway. Enzyme‐linked immunosorbent assay, quantitative real‐time PCR and Western blotting assays were employed. ELISA results demonstrated that the proinflammatory cytokine levels of interleukins‐6 (IL‐6) and tumour necrosis factor α (TNF‐α) in the serum and synovial fluid and HIF‐1α level in the synovial fluid were significantly elevated in OA patients compared to normal healthy subjects. Moreover, the Western blotting results indicated that the protein expression of HIF‐1α was significantly higher in the cartilage tissues of OA patients. OA patient‐derived chondrocytes were stimulated by IL‐1β and treated with different concentration of vitexin for 24 hours. Vitexin showed no cytotoxicity and increased the survival of chondrocytes under IL‐1β stimulation. Vitexin suppressed IL‐1β‐induced production of NO and prostaglandin E2 (PGE₂) in chondrocytes culture. The treatment of vitexin significantly inhibited IL‐1β‐induced expressions of proinflammatory cytokine levels of IL‐6, TNF‐α, matrix metalloproteinase (MMP)‐1, MMP‐3 and MMP‐13. Furthermore, Western blotting results demonstrated that HIF‐1α is involved in vitexin's protective effects on IL‐1β‐stimulated injuries in OA patient‐derived chondrocytes. Our study demonstrates that vitexin alleviates IL‐1β‐induced inflammatory responses in chondrocytes from osteoarthritis patients, which may be attributed partly to the inhibition of HIF‐1α pathway.     

An immunohistochemical examination of the expression of E-cadherin, α- and β/γ-catenins,and α2- and β1-integrins in invasive breast cancer

This study examines the expression of the cell–cell adhesion molecules E-cadherin and its associated proteins, the catenins and the matrix–cell adhesion molecules β1- and α2-integrins, in primary invasive breast carcinoma. Expression was assessed immunohistochemically on frozen sections by semi-quantitative scoring of the intensity and proportion of immunoreactivity in 55 cases. Associations with each other and with other histological and prognostic features and survival were sought. There was a significant association between loss of E-cadherin expression and loss of α- and β/γ-catenin immunostaining. In 20 per cent of cases, membranous immunoreactivity with E-cadherin antibody was absent. Absent cytoplasmic expression of α- and β/γ-catenins was seen in 24 and 22 per cent of breast cancers, respectively. The intensity of reactivity with E-cadherin showed a significant association with histological grade (p = 0·002) and tumour type (p < 0·001). Lobular carcinomas frequently showed loss of expression of E-cadherin, as reported elsewhere; loss of catenin expression was also found in these tumours. α-Catenin intensity also showed a relationship with grade (p = 0·008) and with oestrogen receptor (ER) status (p = 0·006). β/γ-Catenin expression was not associated with other known prognostic factors. Forty-nine per cent and 42 per cent of cases showed no membrane immunostaining with β1- and α2-integrin, respectively, and co-ordinated loss of β1- and α2-integrin expression was found. Both β1- and α2-integrin expression were associated with histological grade (p = 0·003 and p = 0·031, respectively) and β1 immunoreactivity with tumour type (p = 0·010). None of the variables examined showed a statistically significant association with tumour size or lymph node stage, or with overall survival, although a trend was seen (p = 0·087) towards poorer survival of patients with tumours with absent or weak expression of β1-integrin. The expression of these markers is of biological interest, but appears to be of little additional use in predicting clinical behaviour. Copyright © 1999 John Wiley & Sons, Ltd.     

Functional analysis of α1β1 integrin in human natural killer cells

Upon activation with interleukin (IL)-2 human natural killer (NK) cells acquire on their surface the α1β1 and α2β1 integrins and down-regulate the expression of α6β1. By employing α1β1-specific monoclonal antibody (mAb) HP-2B6, characterized in our laboratory, we examined the functional role of the α1β1 integrin in NK cells. Treatment with HP-2B6 mAb partially interfered with attachment of cultured NK cells to type I collagen, and combined with an anti-α2β1 (TEA 1/41) mAb, it completely abrogated cell adhesion to this extracelular matrix protein. In contrast, NK cell attachment to laminin was completely blocked by the anti-β1 LIA 1/2 mAb, but was unaffected by α1 and α2-specific mAb; as α3β1 and α6β1 were undetectable, the data indicate that the α1β1 integrin binding sites for type I collagen and laminin are different. Incubation with anti-α1 HP-2B6 or its F(ab')₂ fragments specifically induced a rapid homotypic aggregation of NK cells that was dependent on active metabolism, an intact cytoskeleton and the presence of divalent cations (Ca²⁺ and Mg²⁺); homotypic cell adhesion was selectively blocked by anti-CD18, CD11a or CD54 mAb. In addition, stimulation of cultured NK cells with the anti-α1 HP-2B6 enhanced TNF-α production and induced tyrosine phosphorylation of a 110-kDa protein. Pretreatment with specific inhibitors of protein tyrosine kinase (PTK) activity (tyrphostin 25 and herbimycin A) completely abrogated the functional effects induced by the anti-α1 HP-2B6 mAb. Our data show that ligation of the α1β1 integrin positively modulates IL-2-activated NK cell function via a PTK-dependent pathway.