Early Invasive Growth Research Articles

A novel Botrytis cinerea-specific gene BcHBF1 enhances virulence of the grey mould fungus via promoting host penetration and invasive hyphal development.

Summary Botrytis cinerea is the causative agent of grey mould on over 1000 plant species and annually causes enormous economic losses worldwide. However, the fungal factors that mediate pathogenesis of the pathogen remain largely unknown. Here, we demonstrate that a novel B. cinerea‐specific pathogenicity‐associated factor BcHBF1 (hyphal branching‐related factor 1), identified from virulence‐attenuated mutant M8008 from a B. cinerea T‐DNA insertion mutant library, plays an important role in hyphal branching, infection structure formation, sclerotial formation and full virulence of the pathogen. Deletion of BcHBF1 in B. cinerea did not impair radial growth of mycelia, conidiation, conidial germination, osmotic‐ and oxidative‐stress adaptation, as well as cell wall integrity of the ∆Bchbf1 mutant strains. However, loss of BcHBF1 impaired the capability of hyphal branching, appressorium and infection cushion formation, appressorium host penetration and virulence of the pathogen. Moreover, disruption of BcHBF1 altered conidial morphology and dramatically impaired sclerotial formation of the mutant strains. Complementation of BcHBF1 completely rescued all the phenotypic defects of the ∆Bchbf1 mutants. During young hyphal branching, host penetration and early invasive growth of the pathogen, BcHBF1 expression was up‐regulated, suggesting that BcHBF1 is required for these processes. Our findings provide novel insights into the fungal factor mediating pathogenesis of the grey mould fungus via regulation of its infection structure formation, host penetration and invasive hyphal branching and growth.

Invasion of white matter tracts by glioma stem cells is regulated by a NOTCH1-SOX2 positive-feedback loop.

Early invasive growth along specific anatomical structures, especially the white matter tract, is regarded as one of the main causes of poor therapeutic outcome of people with gliomas. We show that some glioma stem cells (GSCs) are preferentially located along white matter tracts, which exhibit a demyelinated phenotype, at the invasive frontier of glioma tissues. These GSCs are CD133+Notch1+, whereas the nerve fibers express the Notch ligand Jagged1. The Notch-induced transcription factor Sox9 promotes the transcription of SOX2 and the methylation level of the NOTCH1 promoter is attenuated by the upregulation of SOX2 to reinforce NOTCH1 expression in GSCs. This positive-feedback loop in a cohort of glioma subjects is correlated with a poor prognosis. Inhibition of Notch signaling attenuates the white-matter-tract tropism of GSCs. These findings provide evidence indicating that the NOTCH1-SOX2 positive-feedback loop controls GSC invasion along white matter tracts.

Extracellular matrix composition modulates PDAC parenchymal and stem cell plasticity and behavior through the secretome.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers. Its aggressiveness is driven by an intense fibrotic desmoplastic reaction in which the increasingly collagen I-rich extracellular matrix (ECM) and several cell types, including cancer stem cells (CSCs), create a tumor-supportive environment. However, how ECM composition regulates CSC dynamics and their relationship with the principle parenchymal tumor population to promote early invasive growth is not yet characterized. For this, we utilized a platform of 3D organotypic cultures composed of laminin-rich Matrigel, representative of an early tumor, plus increasing concentrations of collagen I to simulate malignant stroma progression. As ECM collagen I increases, CSCs progress from a rapidly growing, vascular phenotype to a slower growing, avascular phase, while maintaining their endothelial-like gene signatures. This transition is supported autocrinically by the CSCs and paracrinically by the parenchymal cells via their ECM-dependent secretomes. Indeed, when growing on an early tumor ECM, the CSCs are dedicated toward the preparation of a vascular niche by (a) activating their growth program, (b) secreting high levels of proangiogenic factors which stimulate both angiogenesis and vasculogenic mimicry, and (c) overexpressing VEGFR-2, which is activated by VEGF secreted by both the CSC and parenchymal cells. On Matrigel, the more differentiated parenchymal tumor cell population had reduced growth but a high invasive capacity. This concerted high local invasion of parenchymal cells into the CSC-derived vascular network suggests that a symbiotic relationship between the parenchymal cells and the CSCs underlies the initiation and maintenance of early PDAC infiltration and metastasis.

Targeting different domains of gap junction protein to control malignant glioma.

A rational treatment strategy for glioma, the most common primary central nervous system tumor, should focus on early invasive growth and resistance to current therapeutics. Connexin 43 (Cx43), a gap junction protein, plays important roles not only in the development of the central nervous system and but also in the progression of glioma. The different structural domains of Cx43, including extracellular loops, transmembrane domains, and an intracellular carboxyl terminal, have distinct functions in the invasion and proliferation of gliomas. Targeting these domains of Cx43, which is expressed in distinct patterns in the heterogeneous glioma cell population, can inhibit tumor cell invasion and new tumor formation. Thus, this review summarizes the structural characteristics of Cx43, the effects of regulating different Cx43 domains on the biological characteristics of glioma cells, intervention strategies targeting different domains of Cx43, and future research directions.

YB-1 expression promotes pancreatic cancer metastasis that is inhibited by microRNA-216a

Pancreatic cancer is one of the most aggressive cancers. The vast majority of patients are diagnosed with advanced, unresectable disease because of early invasive growth and metastatic spread. The aim of this study was to examine YB-1 expression in pancreatic cancer and determine its effects on cell invasion. YB-1 is overexpressed in pancreatic cancer cell lines and patient tissue samples. In patient tissues, high YB-1 levels correlated with perineural invasion. Silencing of YB-1 significantly reduced cell invasion with decreased expression of MMPs in vitro. Furthermore, we found that the expression of YB-1 was suppressed by miR-216a via direct binding to the YB-1 3’-untranslated region. MiR-216a and YB-1 expression levels were inversely correlated in pancreatic cancer cell lines. In addition, ectopic expression of miR-216a inhibited cell invasion in vitro. Taken together, our findings suggest that YB-1 may play an important role in mediating metastatic behaviour and that repression of YB-1 by miR-216a could have a promising therapeutic potential to inhibit tumor metastasis in pancreatic cancer.

MACC1 Is Related to Colorectal Cancer Initiation and Early-Stage Invasive Growth

To investigate metastasis associated in colon cancer 1 (MACC1) and MET expression in colorectal adenoma, Tis, early-stage invasive (T1 and T2), and advanced adenocarcinoma with liver metastasis using immunohistochemistry. Ninety-three paraffin-embedded colorectal tumor specimens were immunohistochemically analyzed for MACC1 and MET protein expression. MACC1 expression was upregulated in the transition from adenoma to Tis; its expression was further elevated during tumor progression from Tis to early invasive carcinoma. MET expression was constant from adenoma to Tis and to T1 but significantly increased as tumor progression to T2. Both MACC1 and MET expression were enhanced in advanced carcinoma with liver metastasis. Stepwise elevation of MACC1 expression in key points of colorectal cancer development suggests that MACC1 may contribute to cancer initiation and early invasive growth. High expression of both MACC1 and MET may relate to distant metastasis.

Nodular lymphocyte predominant Hodgkin lymphoma with non-invasive or early invasive growth pattern suggests an early step of the disease with a highly favorable outcome

Nodular lymphocyte predominant Hodgkin lymphoma with non-invasive or early invasive growth pattern suggests an early step of the disease with a highly favorable outcome

Loss of UDP‐ N ‐acetylglucosamine 2‐epimerase/ N ‐acetylmannosamine kinase (GNE) induces apoptotic processes in pancreatic carcinoma cells

Early invasive growth and metastasis are features of pancreatic cancer that rely on its resistance to anoikis, an apoptosis program activated on loss of matrix anchorage. How anoikis is regulated is unclear. UDP-N-acetylglucosamine-2-epimerase/N-acetylmannosamine-kinase (GNE) was silenced, or p16 was overexpressed, in human pancreatic carcinoma cells. Gene expression profiling, enzymatic assays, Western blotting, and cell cycle analysis were conducted. Silencing of GNE, the key enzyme of sialic acid biosynthesis, sensitizes pancreatic cancer cells to anoikis. Accordingly, we observed a loss of GNE enzyme activity in cells, which became anoikis susceptible after transfection with the tumor suppressor p16. Similarly, studies of another cell line with low GNE activity revealed strong anoikis susceptibility, confirming the association of low GNE activity and anoikis susceptibility. Gene expression profiling demonstrated that the loss of GNE triggered the transcriptional activation of the ATF4-ATF3-CHOP pathway, leading to apoptosis in the framework of the unfolded protein response. In silico analysis showed that GNE up-regulation occurred predominantly in pancreatic cancer but also in other malignancies. Delineation of GNE-dependent signaling pathways may provide targets that control anchorage dependence and/or restore drug efficacy, which is of utmost relevance for the treatment of pancreatic cancer.

Urokinase gene expression indicates early invasive growth in squamous cell lesions of the uterine cervix.

The plasminogen activating system plays a key role in the cascade of tumour-associated proteolysis leading to extracellular matrix degradation and stromal invasion. Changes in the expression of this system, consisting of urokinase- and tissue-type plasminogen activators (uPA and tPA, respectively), plasminogen activator inhibitors (PAI-1, PAI-2) and uPA receptor, have been associated with tumour aggressiveness in a variety of solid malignant tumours. This paper describes a study of squamous intraepithelial lesions (SILs, n=36), squamous cell carcinomas (SCCs, n=42), and normal mucosa (n=5) of the uterine cervix by in situ hybridization with (35)S-labelled RNA probes. uPA transcripts were absent from normal mucosa and non-invasive lesions, but present in atypical epithelial cells of all microinvasive carcinomas ( n=19) and in some of the more advanced invasive carcinomas (n=11). PAI-1 transcripts were found in stromal cells of most tissue samples with, however, significantly increased levels in invasive SCC compared with SIL, microinvasive SCC, and normal mucosa. uPA-positive invasive carcinomas often displayed additional PAI-1 expression by tumour cells. At variance with uPA, tPA transcripts were found in atypical epithelial cells of low- and high-grade SILs. In the majority of SCCs tested (27/29 cases), the HPV 16 E6/E7 oncogene and uPA transcription were correlated. uPA and PAI-1 expression indicates invasive growth when expressed by atypical epithelial cells of squamous cervical lesions. Moreover, the presence of uPA transcripts is indicative of early invasive growth. uPA and tPA seem to have different functions in the development of invasive properties in uterine cervical squamous epithelium.

Basement membrane patterns in borderline tumors of the ovary. An immunohistochemical study with antibodies to laminin and type IV collagen.

Using antibodies directed against the basement membrane (BM) components laminin and type IV collagen, basement membrane patterns were studied in borderline epithelial tumors of the ovary. To determine the potential use of BM immunohistochemistry in the histopathologic diagnosis of tumors of borderline category, BM patterns were compared with those in cystadenomas and cystadenocarcinomas. In cystadenomas, regular and intact BM were found at the interface between the epithelial cells of the cysts and the adjacent stroma. Cystadenocarcinomas displayed an irregular pattern, with areas of intact BM between tumor cells and stroma, as well as areas with irregular discontinuities. Tumors of borderline malignancy shared a continuous BM pattern with cystadenomas, However, 30% of the borderline malignant tumors contained small areas with BM interruptions resembling those of invasive carcinoma. From the results of this study we conclude that BM patterns in ovarian tumors of borderline malignancy are mostly similar to those of benign epithelial tumors. Focal defects possibly indicating early invasive growth, however, occur in 30% of the cases.

Is there a Carcinoma in Situ of Gastric Mucosa?

Carcinoma in situ, a precancerous lesion in the strict sense, was first recognized in stratified squamous epithelia. It is characterized by markedly atypical cells replacing the autochthonous epithelial cells without stromal invasion, the basement membrane being well preserved. Notwithstanding gradual transitions between carcinoma in situ on the one hand and dysplasias and invasive cancer on the other hand, its histological separation from the latter is feasible in the uterine portio. Its recognition has decisive therapeutic and prognostic implications, particularly in view of the frequently observed latent period between purely superficial spread and early invasive growth. In contrast difficulties are encountered in applying the concept of Carcinoma in situ to mucosal lesions of the stomach, though an analogous replacement stage has to be postulated, because the gastric and cervical mucous membranes differ fundamentally in their structural characteristics. The epithelial cells of the surface, pits and tubular glands do exhibit progressive atypia during cancerization. However, the single-layered epithelium offers far less distinctive criteria than the stratified squamous epithelium. Newly formed glandular complexes cannot be accepted as evidence for in situ growth. The latent period between purely superficial replacement by atypical cells and invasion appears to be considerably shorter in the stomach than in the portio, probably because the mechanical resistance of the loosely textured gastric lamina propria is small. In addition, stromal invasion may originate from any one epithelial cell in the gastric mucosa, whilst it is just the basal layer from which invasively growing cells may emanate in the uterine portio. The occurrence of dysplasia in the mucosa of the stomach does not justify a gastrectomy, according to our current experience, there being no intervention in gastric surgery equivalent to that of conization.

MICROINVASIVE CARCINOMA OF THE UTERINE CERVIX

MICA is the transition stage from intraepithelial growth to clinical invasive cancer. The early invasive growth must be accepted as an indication that the lesion is significant; it may be self-healing but it is objective evidence of progression and invasion remains the most significant indication of malignancy. The subjective changes of CIS, nuclear enlargement, pleomorphism of nuclei, altered nuclear-cytoplasmic ratio, etc., are transcended and the recognition and diagnosis of MICA should be facilitated for the pathologist. Treatment which tends to be conservative is more widely accepted, but the disease can be lethal and the most serious complication appears to be, like CIS, vaginal recurrence.

An electron microscopic study of early invasive growth in human skin tumours and laryngeal carcinoma

Electron microscopic studies of the morphogenesis of squamous cell carcinoma revealed the loosening up of cell contacts in the course of carcinogenesis. Cell degeneration plays a part in the development of the loss of cell cohesion and in commencement of invasive growth. In the preneoplastic phase, before any massive destruction of the basement membrane takes place, cytoplasmic processes originating from epithelial cells, penetrate into the connective tissue through gaps in the basement membrane. This phenomenon is referred to as micro-invasion at the electron microscopic level. The fine structure of cell particles containing nucleo-proteins, i.e. chromatin particles and also interchromatinic granules, undergoes considerable modification in the course of carcinogenesis.

The diagnosis of very early carcinoma of the uterine cervix during pregnancy

W E BELIEVE that pregnant women offer favorable opportunity for detection of incipient cancer of the cervix uteri and will present material in support of such opinion. This is based on discovery of one very early malignancy by random biopsies of friable or bleeding cervical erosions among 2,000 pregnanciesl; and one early invasive growth, plus one quest,ionable carcinoma in situ from 1,600 cytological screenings2 previously reported. To this we now add a small new series of 500 Papanicolaou cervical smears showing 3 highly suspicious cervical lesions but no cancer. There are certain difficulties in the search for early cancer of the cervix during pregnancy which are responsible for. much skepticism concerning the value of such effort. The most important criticisms are: (1) infrequency of cervical cancer in relatively young age groups; (2) gross and microscopic changes in the cervix during pregnancy frequently simulate early malignancy; (3) limitations of cytologic cervical smears and unreliability of single smear tests for screening purposes; (4) inability to secure safely really adequate biopsy material such as complete sharp or cold cervical conization, due to risk of hrmorrhagc. These four questions will be discussed in order. Our two cervical malignancies, one questionable carcinoma in situ, and three suspicious cases were all in multigravidas averaging 31 years of age and parity iv. However, there is ample evidence to indicate variable prolonged dormant stages of both preinvasive and invasive cervical cancer. Nearly one-half of all of our patients showed gross cervical lesions, mostly simple, elevated, papillary or polypoid “erosion,” generally friable, including many polyps and some condylomas, all of which were biopsied and a few found to be decidual. If we add to the above features, bleeding from threatened abortion, cervical discharge, and vaginal exudate due to frequent Trichomonns ,uaginnlis or mycotic vaginitis, it is obvious that neither subjective symptoms nor simple inspection provides reliable basis for suspecting cancer. Microscopic diagnosis of preinvasive cervical cancer during pregnancy can be positive after multiple expert opinions or prolonged post,natal observations or both, but early invasive cancer can be det,ermined immediatcl$. Biopsy diagnosis of carcinoma in situ from the nonpregnant cervix is difficult, as shown by Novak and Galvin,3 who reported 25 cases not confirmed after operation. Error in these cases was attributed to misinterpretation of varying degrees of basal-ccl1 hyper.I__ *Rear1 at a meeting of the Philadelphia Obstetrical Society. March 6. 1950.