Annulate Lamellae in a Large Cell Lung Carcinoma Cell Line with High Expression of Tyrosine Kinase Receptor and Proto-Oncogenes

c-MET as a potential therapeutic target and biomarker in cancer

The receptor tyrosine kinase c-MET and its ligand, hepatocyte growth factor (HGF), regulate multiple cellular processes that stimulate cell proliferation, invasion and angiogenesis. This review provides an overview of the evidence to support c-MET or the HGF/c-MET signaling pathway as relevant targets for personalized cancer treatment based on high frequencies of c-MET and/or HGF overexpression, activation, amplification in non-small cell lung carcinoma (NSCLC), gastric, ovarian, pancreatic, thyroid, breast, head and neck, colon and kidney carcinomas. Additionally, the current knowledge of small molecule inhibitors (tivantinib [ARQ 197]), c-MET/HGF antibodies (rilotumumab and MetMAb) and mechanisms of resistance to c-MET-targeted therapies are discussed.

Ultrastructural and antigenic properties of neural stem cells and their progeny in adult rat subventricular zone

Neural stem cells (NSCs) in the subventricular zone (SVZ) continuously generate olfactory bulb interneurons in the adult rodent brain. Based on their ultrastructural and antigenic properties, NSCs, transient amplifying precursor cells, and neuroblasts (B, C, and A cells, respectively) have been distinguished in mouse SVZ. Here, we aimed to identify these cell types in rat SVZ ultrastructurally and at the light microscopy level, and to determine the antigenic properties of each cell type using gold and fluorescence immunolabeling. We found astrocytes with single cilia (NSCs, correspond to B cells) and neuroblasts (A cells). We also observed mitotic cells, ependymal cells, displaced ependymal cells, and mature astrocytes. In contrast, transient amplifying precursor cells (C cells) were not detected. The NSCs and neuroblasts had epidermal growth factor receptor (EGFR) and platelet-derived growth factor receptor alpha (PDGFRalpha) expressed on the ciliary apparatus and were the only cell types incorporating the proliferation marker BrdU. Throughout mitosis, EGFR and PDGFRalpha were associated with the microtubule of the mitotic spindle. Ependymal and displaced ependymal cells also expressed EGFR and PDGFRalpha on their cilia but did not incorporate BrdU. Our findings indicate that the NSCs in adult rat SVZ give rise directly to neuroblasts. During mitosis, the NSCs disassemble the primary cilium and symmetrically distribute EGFR and PDGFRalpha among their progeny.

Suppression subtractive hybridization and expression profiling identifies a unique set of genes overexpressed in non-small-cell lung cancer

Expression array data for >3000 individual clones from two suppression subtractive hybridization libraries revealed 147 genes overexpressed in non-small-cell lung cancer (NSCLC) cell lines. Of these 147 genes, 30 genes have previously unknown cancer association and 65 genes have been associated with cancers other than NSCLC. The identification of 52 genes previously associated with NSCLC by different methodologies supports the validity of the strategy used here. Of the 147 genes, 19 have no prior named Unigene cluster designation, and are designated herein as L1 to L19. Quantitative real-time PCR and cancer profiling arrays were used as independent validation tools to confirm tumor overexpression for five of the 'L' genes in tumor cell lines and patient samples from NSCLC and other cancers. Follow-up studies for candidate NSCLC-associated genes can be useful in providing valuable insight into the etiology of lung cancer as well as providing potentially interesting diagnostic or therapeutic targets for further investigation.

Regulation of E-cadherin/catenin complex patterns by epidermal growth factor receptor modulation in human lung cancer cells

We previously demonstrated that a ligand-blocking monoclonal antibody (mAb) against the epidermal growth factor-receptor (EGF-R), LA1, induced morphological conversion from epithelial-like to epithelial of the human lung cancer cell line, H322. This was accompanied by an up-regulation of epithelial cadherin (E-cadherin) expression (Clin. Cancer Res. 5 (1999) 681). In the present paper, we show that mAb LA1 induces the epithelial-like to epithelial conversion of the human lung cancer cell line, A549. In A549 and H322 cells, which express a detectable amount of EGF-R (ErbB-1), ErbB-2, ErbB-3, and ErbB-4 receptors, the LA1 mAb induces up-regulation of the E-cadherin/catenin complex (alpha-, beta-, and gamma-catenins). This is associated with re-localization of E-cadherin, alpha-catenin, (and to a lesser extent beta-catenin), but not gamma-catenin. Additionally, we report that mAb LA1 inhibits cell motility. In contrast, epidermal growth factor (EGF) or heparin-binding EGF-like growth factor (HB-EGF) induces the epithelial-like to fibroblastoid conversion of A549 and H322 cell lines, slightly reduces the expression of E-cadherin and beta-catenin, but not alpha- and gamma-catenins, and stimulates cell motility. These studies demonstrate that EGF-R modulation regulates the E-cadherin/catenin complex and cell motility in human lung epithelial carcinoma cells. Our results may have important therapeutic implications for the treatment of invasive human lung carcinomas via the restoration of the cadherin/catenin complex using inhibitors of EGF-R.

Vascular endothelial growth factor and hepatocyte growth factor levels are differentially elevated in patients with advanced retinopathy of prematurity

Although the roles of vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) in angiogenesis are well described, the putative roles of these factors in retinopathy of prematurity (ROP) remain unknown. We evaluated VEGF and HGF protein levels in subretinal fluid of eyes with ROP, and expression of their corresponding receptors in retrolental membranes associated with stage 5 ROP. We examined subretinal fluid samples from eyes using rhegmatogenous retinal detachment as a control. VEGF and HGF were differentially elevated in eyes with ROP. In Stage 5 ROP (n = 22), the mean VEGF and HGF levels were 14.77 +/- 14.01 ng/ml and 16.56 +/- 9.62 ng/ml, respectively. Interestingly, in patients with active stage 4 ROP, mean VEGF levels were highly elevated (44.16 +/- 18.72 ng/ml), whereas mean HGF levels remained very low (4.77 +/- 2.50 ng/ml). Next, we investigated in vivo expression of VEGF receptor-2 and HGF receptor in retrolental membranes from 16 patients with stage 5 ROP. Both VEGF receptor-2 and HGF receptor proteins were detected mainly in posterior portions of the membrane as well as in vessel walls and along the retinal interface where angiogenesis was active. These findings together suggest that VEGF and HGF play important roles in the pathogenesis of ROP.

Fine structural changes in the ileum of mice fed on delta-endotoxin-treated potatoes and transgenic potatoes

The present work has been designed to study the effect of feeding on transgenic potatoes, which carry the CryI gene of Bacillus thuringiensis var. kurstaki strain HD1, on the light and electron microscopic structure of the mice ileum, in comparison with feeding on potatoes treated with the 'delta-endotoxin' isolated from the same bacterial strain. The microscopic architecture of the enterocytes of the ileum of both groups of mice revealed certain common features such as the appearance of mitochondria with signs of degeneration and disrupted short microvilli at the luminal surface. However, in the group of mice fed on the 'delta-endotoxin', several villi appeared with an abnormally large number of enterocytes (151.8 in control group versus 197 and 155.8 in endotoxin and transgenic-treated groups, respectively). Fifty percent of these cells were hypertrophied and multinucleated. The mean area of enterocyte was significantly increased (105.3 microm(2) in control group versus 165.4 microm(2) and 116.5 microm(2) in endotoxin and transgenic-treated groups, respectively). Several forms of secondary lysosomes or auotophagic vacuoles were recognized in these cells. These changes were confirmed with the scanning electron microscope which revealed a remarkable increase in the topographic contour of enterocytes (23 microm in control group versus 44 microm and 28 microm in endotoxin and transgenic-treated groups, respectively) at the divulged surface of the villi. The basal lamina along the base of the enterocytes was damaged at several foci. Several disrupted microvilli appeared in association with variable-shaped cytoplasmic fragments. Some of these fragments contained endoplasmic reticulum, as well as ring-shaped annulate lamellae. In addition, the Paneth cells were highly activated and contained a large number of secretory granules. These changes may suggest that delta-endotoxin-treated potatoes resulted in the development of hyperplastic cells in the mice ileum. Although mild changes are reported in the structural configuration of the ileum of mice fed on transgenic potatoes, nevertheless, thorough tests of these new types of genetically engineered crops must be made to avoid the risks before marketing.

Autotaxin expression in non-small-cell lung cancer

Autotaxin (ATX) is one of the newly discovered autocrine motility-stimulating factors with peptide sequences identical to those of the brain-type phosphodiesterase I (PD-Ialpha). Although ATX/PD-Ialpha is believed to play a role in tumor progression, its expression in various human cancers has not been extensively studied. We have studied the expression of ATX messenger RNA (mRNA) in normal human bronchial epithelial cell (HBEC) and non-small-cell lung cancer (NSCLC) cell lines, and in primary NSCLC with their corresponding normal lung tissues, using reverse transcription-polymerase chain reaction, Northern blot analysis, and in situ hybridization. ATX mRNA was commonly expressed in these cell lines and tissues. The predominantly expressed mRNA species corresponded to the ATX complementary DNA isolated from a human teratocarcinoma cell line. Overexpression of ATX mRNA was detected in seven of 12 (58%) tumor cell lines; however, there was no correlation between the levels of expression of ATX mRNA and the spontaneous motility of these cells. In situ hybridization localized ATX mRNA expression to the basal cells of normal bronchial epithelium, stromal B lymphocytes, and tumor cells. An overexpression of ATX mRNA as compared with its expression in normal bronchial epithelium was mainly found in poorly differentiated carcinomas. Our findings suggest that ATX may have roles additional to its motility-stimulating function in undifferentiated NSCLC.

Differential expression of Met/hepatocyte growth factor receptor in subtypes of non-small cell lung cancers

Hepatocyte growth factor (HGF)/scatter factor (SF) is a multifunctional factor that stimulates epithelial cell motility, invasion and morphogenesis. Its receptor is a transmembrane tyrosine kinase encoded by the Met proto-oncogene. Several studies have suggested a possible role for HGF/Met in tumor development and progression. To investigate the potential roles of Met in human lung cancer biology, we have studied the mRNA and protein expression of Met in normal lung tissue, primary non-small cell lung carcinoma (NSCLC), and NSCLC cell lines. The results indicated a differential pattern of Met expression among various subtypes of NSCLC. The majority of squamous cell carcinoma (SQCC), either in vivo or in vitro, expressed Met mRNA and its protein product at levels much lower than or similar to normal lung tissue or bronchial epithelium. Moreover, SQCC characteristically over-expressed a variant Met mRNA which corresponds to a 5' partially deleted transcript produced by alternative splicing. In contrast, the expression of Met mRNA and its protein product in adenocarcinoma (ADC) and large cell undifferentiated carcinoma were more heterogeneous. Overexpression was demonstrated in approximately 35% and 20% of these subtypes of NSCLC, respectively. Among ADC, intermediate to high levels of Met immunoreactivity correlated with greater degree of tumor differentiation. Furthermore, an accentuation of Met immunoreactivity was often noted in cancer cells at the advancing edge of tumors. These findings support a role for Met in lung cancer cell invasion and differentiation in vivo, but its expression and functions may be modified by the differentiation phenotype of the tumor cells.

In vitro synergy of paclitaxel (Taxol) and vinorelbine (navelbine) against human melanoma cell lines

Paclitaxel (PTXL) (Taxol), a taxane, and vinorelbine (VRB), a semisynthetic vinca alkaloid drug, have tubulin as their common intracellular target, but inhibit growth by binding to different sites. We evaluated in vitro the antiproliferative activity of these two drugs as single agents and in combination, against two human melanoma cell lines, G361 and StM111a. The SRB (sulphorhodamine B) assay was used to determine growth inhibition. Possible drug-drug interaction at the cellular level was assessed by constructing Isoboles (Isobologram analysis) and applying the concept of an 'envelope of additivity'. Both agents were active in the nanomolar range at clinically achievable concentrations. The mean IC50 for G361 was 46.6 nM (PTXL) and 19.9 nM (VRB) after a 1 h drug exposure. Mean IC50 (1 h) for StM111a was 9.7 nM (PTXL) and 26.9 nM (VRB). Isobole analysis at the isoeffect levels of 25%, 50% and 75% indicated that drug interaction was predominantly synergistic (supra-additive) when paclitaxel and VRB were added concurrently for 1 h to cultures of StM11 1a or G361. In some experiments, this synergy was observed with particularly low concentrations of paclitaxel (3 nM) and VRB (0.01 nM). A new points were located within the envelope of additivity or in the subadditive (antagonism) region of the isobole. An overall synergy was also found if the data were analysed by the median effect analysis. The effect of these agents on the cytoskeleton and ultrastructure were studied with immunofluorescence and electron microscopy, respectively. These results confirm the in vitro inhibitory activity of paclitaxel and VRB against malignant melanoma, but more importantly the two drugs appear to act synergistically at relatively low concentrations.

Electron microscopic studies of peripheral blood mononuclear cells in chronic type C hepatitis treated with interferon-alpha

Electron microscopic studies of peripheral blood mononuclear cells (PBMC) in chronic type C hepatitis revealed several interesting structures after interferon-alpha (IFN-alpha) therapy. Fifteen of 20 patients were treated with IFN-alpha. Tubuloreticular inclusions (TRI) were observed in only one patient who did not receive therapy. In contrast, TRI were observed in 10 of 15 (66.7%) patients who underwent the therapy for 2 weeks to 6 months. Cylindric confronting cisternae (CCC) were identified in the cytoplasm of PBMC in 4 of 16 (25%) patients who underwent the therapy. CCC were found only after IFN-alpha therapy. The appearance of both TRI and CCC in the PBMC was significantly correlated to IFN-alpha therapy. Although there is little evidence about the morphogenesis of TRI and CCC, these structures may be a host response to IFN-alpha induced by hepatitis C virus infection.

Maxillary adenoid cystic carcinoma with annulate lamellae

Of 29 reviewed ultrastructural studies of adenoid cystic carcinoma, only 1 mentions the presence of annulate lamellae. The present report describes a 65-year-old woman who presented with an adenoid cystic carcinoma in her left maxillary sinus. At the light microscopic level, most of the connective tissue was loose and myxomatous and contained fine strands, cords, and islands of epithelium that in places had a cribriform pattern. The ultrastructural appearance was similar to that described by others. Two epithelial cell types predominated. The cytoplasm of one type contained mainly ribosomes, and that of the other type also had peripheral microfilaments. Also present were pseudocysts, lumina with microvilli, and replicated basal lamina. In addition, a number of both types of cells contained parallel arrays of cisternae that had regular small pores. These were annulate lamellae.