Integrin expression in squamous neoplasia of the cervix

The design of peptide-amphiphiles as functional ligands for liposomal anticancer drug and gene delivery

Liposomal nanomedicine has led to clinically useful cancer therapeutics like Doxil and DaunoXome. In addition, peptide-functionalized liposomes represent an effective drug and gene delivery vehicle with increased cancer cell specificity, enhanced tumor-penetrating ability and high tumor growth inhibition. The goal of this article is to review the recently published literature of the peptide-amphiphiles that were used to functionalize liposomes, to highlight successful designs that improved drug and gene delivery to cancer cells in vitro, and cancer tumors in vivo, and to discuss the current challenges of designing these peptide-decorated liposomes for effective cancer treatment.

Targeting HPV-infected cervical cancer cells with PEGylated liposomes encapsulating siRNA and the role of siRNA complexation with polyethylenimine

The greatest obstacle to clinical application of cancer gene therapy is lack of effective delivery tools. Gene delivery vehicles must protect against degradation, avoid immunogenic effects and prevent off target delivery which can cause harmful side effects. PEGylated liposomes have greatly improved tumor localization of small molecule drugs and are a promising tool for nucleic acid delivery as the polyethylene glycol (PEG) coating protects against immune recognition and blood clearance. In this study, small interfering RNA (siRNA) was fully encapsulated within PEGylated liposomes by complexing the siRNA with a cationic polymer, polyethyleneimine (PEI), before encapsulation. Formation methods and material compositions were then investigated for their effects on encapsulation. This technology was translated for protective delivery of siRNA designed for human papillomavirus (HPV) viral gene silencing and cervical cancer treatment. PEGylated liposomes encapsulating siRNA were functionalized with the AG86 targeting peptide-amphiphile which binds to the α6β4 integrin, a cervical cancer biomarker. It was found that both targeting and polymer complexation before encapsulation were critical components to effective transfection.

Integrative topological analysis of mass spectrometry data reveals molecular features with clinical relevance in esophageal squamous cell carcinoma

Combining MS-based proteomic data with network and topological features of such network would identify more clinically relevant molecules and meaningfully expand the repertoire of proteins derived from MS analysis. The integrative topological indexes representing 95.96% information of seven individual topological measures of node proteins were calculated within a protein-protein interaction (PPI) network, built using 244 differentially expressed proteins (DEPs) identified by iTRAQ 2D-LC-MS/MS. Compared with DEPs, differentially expressed genes (DEGs) and comprehensive features (CFs), structurally dominant nodes (SDNs) based on integrative topological index distribution produced comparable classification performance in three different clinical settings using five independent gene expression data sets. The signature molecules of SDN-based classifier for distinction of early from late clinical TNM stages were enriched in biological traits of protein synthesis, intracellular localization and ribosome biogenesis, which suggests that ribosome biogenesis represents a promising therapeutic target for treating ESCC. In addition, ITGB1 expression selected exclusively by integrative topological measures correlated with clinical stages and prognosis, which was further validated with two independent cohorts of ESCC samples. Thus the integrative topological analysis of PPI networks proposed in this study provides an alternative approach to identify potential biomarkers and therapeutic targets from MS/MS data with functional insights in ESCC.

T-Cadherin is an auxiliary negative regulator of EGFR pathway activity in cutaneous squamous cell carcinoma: impact on cell motility

Genetic and epigenetic studies in different cancers, including cutaneous carcinomas, have implicated T-cadherin (T-cad) as a tumor suppressor. Immunohistochemical and in vitro studies have suggested that T-cad loss promotes incipient invasiveness in cutaneous squamous cell carcinoma (SCC). Molecular mechanisms are unknown. This study found that the main consequence of T-cad silencing in SCC is facilitation of ligand-dependent EGFR activation, whereas T-cad overexpression impedes EGFR activation. Gain- and loss-of-function studies in A431 SCC cells demonstrate T-cad-controlled responsiveness to EGF with respect to pharmacological inhibition of EGFR and to diverse signaling and functional events of the EGFR activation cascade (EGFR phosphorylation, internalization, nuclear translocation, cell retraction/de-adhesion, motility, invasion, integrin β1, and Rho small GTPases such as RhoA, Rac1, and Cdc42 activation). Further, T-cad modulates the EGFR pathway activity by influencing membrane compartmentalization of EGFR; T-cad upregulation promotes retention of EGFR in lipid rafts, whereas T-cad silencing releases EGFR from this compartment, rendering EGFR more accessible to ligand stimulation. This study reveals a mechanism for fine-tuning of EGFR activity in SCC, whereby T-cad represents an auxiliary "negative" regulator of the EGFR pathway, which impacts invasion-associated behavioral responses of SCC to EGF. This action of T-cad in SCC may serve as a paradigm explaining other malignancies displaying concomitant T-cad loss and enhanced EGFR activity.

Integrin beta1 is required for the invasive behaviour but not proliferation of squamous cell carcinoma cells in vivo

Integrin β1 is both overexpressed and in an ‘active’ conformation in vulval squamous cell carcinomas (VSCCs) compared to matched normal skin. To investigate the significance of integrin β1 deregulation we stably knocked-down integrin β1 expression in the VSCC cell line A431. In vitro analysis revealed that integrin β1 is required for cell adhesion, cell spreading and invasion. However, integrin β1 is not required for cell growth or activation of FAK and ERK signalling in vitro or in vivo. Strikingly, while control tumours were able to invade the dermis, integrin β1 knockdown tumours were significantly more encapsulated and less invasive.

Changes of cell adhesion and extracellular matrix (ECM) components in cervical intraepithelial neoplasia

Cell-cell and cell-extracellular matrix interaction is crucial in tumor progression. Tight junction (TJ) proteins as occludin and claudins (CLDNs) play important role in this process together with several extracellular matrix components, as syndecan. Our previous work suggested significant changes in the expression of claudins even in the early stages of cervical carcinogenesis. The aim of our present work was to study the expression of occludin and syndecan-1, as compared to CLDNs, in early phases of cervical carcinogenesis. Paraffin sections of 50 samples were studied by immunohistochemistry, including cervical intraepithelial neoplasias (CINI-II-III), in situ carcinomas (CIS) and normal cervical samples. Occludin and CLDN-2 were found colocalized in the basal layer, while syndecan-1 and CLDN-1, -4 and -7 were coexpressed in the parabasal and intermedier layers in normal epithelia. Intensity of occludin staining decreased in CIN/CIS lesions, although it was more extended towards the upper epithelial layers with inverse relation with grades, as seen in the case of CLDN-2 expression. CLDN-1, -2, -4 and -7 were detected in the entire epithelium in CIN, showing decrease in CIS. The progression of CIN was associated with reduced syndecan-1 expression, in contrast to CLDN-1, -4 and -7 which increased toward CIS. The obtained data suggest that significant changes occur in the composition of cell adhesion complexes even in early stages of cervical carcinogenesis. The pattern of expression is characteristic for the alteration, the changes in the different components, however, are not parallel with each other.

Evaluation of a selectively oncolytic adenovirus for local and systemic treatment of cervical cancer

Treatment options for disseminated cervical cancer remain inadequate. Here, we investigated a strategy featuring Ad5-Delta 24 RGD, an oncolytic adenovirus replication-competent selectively in cells defective in the Rb-p16 pathway, such as most cervical cancer cells. The viral fiber contains an alpha(v)beta(3) and alpha(v)beta(5) integrin-binding RGD-4C motif, allowing coxsackie-adenovirus receptor-independent infection. These integrins have been reported to be frequently upregulated in cervical cancer. Oncolysis of cervical cancer cells was similar to a wild-type control in vitro. In an animal model of cervical cancer, the therapeutic efficacy of Ad5-Delta 24 RGD could be demonstrated for both intratumoral and intravenous application routes. Biodistribution was determined following intravenous administration to mice. Further preclinical safety data were obtained by demonstrating lack of replication of the agent in human peripheral blood mononuclear cells. These results suggest that Ad5-Delta 24 RGD could be useful for local or systemic treatment of cervical cancer in patients with disease resistant to currently available modalities.

Histologic and immunophenotypic classification of cervical carcinomas by expression of the p53 homologue p63: a study of 250 cases

Recent studies of the p53 homologue p63 indicate that this gene is preferentially expressed in basal and immature cervical squamous epithelium. This study correlated p63 expression with morphologic phenotype and human papillomavirus (HPV) type in a wide range of cervical neoplasms. Two hundred fifty cases of cervical carcinoma, including squamous cell carcinoma (SCCA; n = 178), adenocarcinoma (ADCA; n = 28), adenosquamous carcinoma (ASCA; n = 8), neuroendocrine carcinoma (NECA; n = 15), and other variant or mixed types (n = 21) were studied. Ninety-seven percent of SCCA, 0% of ADCA, and 0% of SCUC showed strong (>75% v <30%) positivity for p63 (P<.001). p63 sharply distinguished SCCA (p63+) from ADCA (p63-), Large-cell, poorly differentiated carcinomas were distinguished as putative glandular (glassy cell) or squamous (lymphoepithelial-like or spindle cell) types based on p63 staining. Eight (73%) of 11 neuroendocrine tumors tested were chromogranin positive; all showed no or low (<30%) levels of p63 immunostaining. Absence of p63 was also associated with a subset of nonneuroendocrine undifferentiated carcinomas. Transitions from squamous to columnar or undifferentiated morphology coincided with loss of p63 expression. A strong association between HPV 16 and p63 positivity was identified because of the colocalization of both within tumors of squamous phenotype. p63 is a powerful marker for squamous differentiation and, when diffusely expressed, excludes a glandular or neuroendocrine differentiation. p63 may be useful for differentiating pure squamous or glandular from adenosquamous carcinomas, tracking shifts in differentiation within tumors, supporting (by its absence) the diagnosis of neuroendocrine carcinomas, and clarifying the spectrum of poorly differentiated carcinomas lacking either squamous or neuroendocrine differentiation.

Expression of the p53 homologue p63 in early cervical neoplasia

BACKGROUND

p63, a homologue of the tumor suppressor gene p53, is expressed in embryonic, adult murine, and human basal squamous epithelium and encodes both transactivating and dominant negative transcript isoforms. Mouse embryos functionally deficient in p63 fail to replenish basal squamous epithelial cells, resulting in multiple defects that include absent genital squamous epithelium. This study investigated the expression of p63 in the human cervical transformation zone and early cervical neoplasia.

METHODS

Tissue localization of p63 was determined by immunohistochemistry in a wide range of epithelia. A correlation was also made between p63 expression and squamous basal cell (keratin 14), endocervical columnar cell (mucicarmine), and cell-cycle specific (Ki-67) markers.

RESULTS

p63 expression by immunostaining delineated basal and parabasal cells of maturing ectocervical squamous mucosa, squamous metaplasia in the cervix, and basal and subcolumnar cells of the cervical transformation zone. In atrophic epithelia immunostaining for p63 was present in all cell strata. In early cervical neoplasia, p63 expression was inversely correlated with both squamous cell maturation and nonsquamous differentiation in CIN. This biomarker also identified basal cells in a subset of preinvasive cervical neoplasms with endocervical cell differentiation that were bcl-2 and keratin 14 negative.

CONCLUSIONS

In the lower female genital tract, p63 is preferentially expressed in immature cells of squamous lineage and is not linked to cell proliferation. The broader range of p63 expression relevant to keratin 14 and bcl-2 indicates that p63 may identify additional subsets of benign and neoplastic epithelial basal cells in the cervical transformation zone and may be useful in studying cell differentiation in the early stages of neoplastic change in this region.

Expression of beta1 integrin in relation to histological features in normal and neoplastic canine testicles

The expression of the beta1 common chain of the VLA integrin subfamily was evaluated immunohistochemically in a series of five normal and 30 neoplastic canine testicles. The tumours, consisting of seminomas or Sertoli cell tumours, were classified according to WHO criteria as intraductal without signs of invasion, intraductal with signs of invasion, or diffuse. Expression of beta1 integrin decreased progressively from intraductal tumours without signs of invasion, to the diffuse type, in which immunolabelling was generally absent. In a few cases of diffuse neoplasia, groups of neoplastic cells exhibited strong positivity that was not restricted to the basal pole of the cell membrane. These results suggest that the expression of beta1 integrin was related to the histological tumour type, possibly reflecting a specific requirement for a reduction in integrin by neoplastic cells with infiltrative and metastatic potential.

Can alterations in integrin and laminin-5 expression be used as markers of malignancy?

Development of squamous cell carcinomas (SCCs) involves alterations in the adhesive interactions in the epithelium and invasion through the basement membrane. Therefore, changes in the expression of receptors and ligands involved in cell-cell and cell-matrix adhesion may be essential for the transformation of a premalignant into a malignant lesion. The aim of this study was to examine if expression of specific cell adhesion molecules can be used as markers of malignant development. By immunohistochemistry, we examined the expression pattern of integrins alpha2beta1, alpha3beta1, alpha6beta4 and laminin-5 in biopsies from SCCs (n=18), premalignant lesions (leukoplakias, n=21) and non-premalignant tissue with chronic inflammation (n=11). In poorly differentiated SCCs, patchy loss of alpha3beta1, alpha6beta4 and laminin-5 expression was pronounced at the invasion front, whereas there was a tendency to increased expression of alpha2beta1. Analogous to the SCCs, biopsies from the leukoplakias and the non-premalignant inflammatory tissue showed alterations of the expression of alpha3beta1 and alpha6beta4 in the basal cell layers and of laminin-5. However, a characteristic finding in biopsies from leukoplakias was loss of alpha2beta1 and alpha3beta1 in the suprabasal cells. There was no unequivocal expression of the adhesion molecules distinguishing between inflammatory tissue, premalignant, and malignant lesions.

Aetiology, pathogenesis, and pathology of cervical neoplasia

Early epidemiological studies of cervical neoplasia suggested a causal relation with sexual activity and human papillomaviruses (HPVs) have emerged as prime suspects as venerally transmitted carcinogens. HPVs fall into two broad camps: low risk types, associated with cervical condylomas and CIN 1; and high risk types (mostly 16 and 18), found in 50-80% of CIN 2 and CIN 3 lesions, and 90% of cancers. This association with cancer is very strong, with odds ratios of > 15 (often much higher) in case-control studies that are methodologically sound. An infrequently detected third group of intermediate risk type HPVs is associated with all grades of CIN and occasionally with cancers. HPVs have also been detected in a wide range of asymptomatic controls, indicating that other events are required for development of neoplasia such as viral persistence and/or altered expression of viral genes, often following integration of the viral genome. This leaves the two major viral oncogenes, E6 and E7, directly coupled to viral enhancers and promoters, allowing their continued expression after integration. High risk HPV E7 proteins bind and inactivate the Rb protein, whereas E6 proteins bind p53 and direct its rapid degradation. A range of putative cofactors has been implicated in progression: HLA type, immunosuppression, sex steroid hormones, and smoking; most of these cofactors appear to influence progression to CIN 3. The natural history includes progression to CIN 3 in 10% of CIN 1 and 20% of CIN 2 cases, whereas at least 12% of CIN 3 cases progress to invasive carcinoma. Cervical glandular intraepithelial neoplasia (CGIN) often coexists with squamous CIN, and the premalignant potential of high grade CGIN is not in doubt, but the natural history of low grade CGIN remains uncertain. A high proportion of CGIN lesions and adenocarcinomas are HPV positive, and HPV18 has been implicated more in glandular than in squamous lesions. A strong clinical case for the application of HPV typing of cells recovered from cervical scrapes can be made; however, a rigorous cost-benefit analysis of introducing HPV typing into the cervical screening programme is required. Prophylactic and therapeutic HPV vaccines are under development. This article reviews the aetiology, pathogenesis, and pathology of cervical neoplasia, emphasising the role of HPVs.

E-cadherin and integrin cell adhesion molecule expression in invasive and in situ carcinoma of the cervix

Integrin and E-cadherin cell adhesion molecules are important in the maintenance of normal epithelial structures, and altered expression of these molecules may be important in epithelial tumors, particularly in the processes of invasion and metastasis. This study examines the immunohistochemical expression of the alpha2beta1, alpha3beta1, alpha6, and beta4 integrins and of E-cadherin in high-grade cervical intraepithelial neoplasia (CIN) and in invasive carcinoma of the cervix. Abnormal expression of E-cadherin and of all of the integrin subunits examined was detected in the dysplastic epithelium in CIN in the majority of cases, but in a minority of cases this expression was lost in the superficial layers of the dysplastic epithelium. Diffuse expression of E-cadherin and of all of the integrins was seen in the majority of cases of invasive cervical carcinoma. Abnormal expression of integrin cell adhesion molecules occurs in the majority of cases of high-grade CIN, and E-cadherin expression is retained in the dysplastic epithelium. Diffuse expression of integrins and of E-cadherin also occurs in invasive carcinoma, but as the expression pattern was similar in all cases of carcinoma, no correlation with outcome is possible and the significance of this expression is unclear.

Correlation of alpha 2 beta 1 integrin expression with histological type and hormonal receptor status in breast carcinomas

Interactions between cells and extracellular matrix are mediated in part by a family of alpha beta heterodimeric molecules known as integrins. Immunohistochemical studies have shown that benign hyperplastic/neoplastic mammary epithelium expressed high levels of alpha 2 beta 1 collagen/laminin receptor. In contrast, malignant cells of breast carcinoma exhibited marked diminuition or loss of the alpha 2 beta 1 integrin. A correlation has been suggested between the loss of the alpha 2 beta 1 expression and the increased invasiveness of neoplastic cells. This study investigated the expression of alpha 2 beta 1 integrin and its extracellular ligand collagen TV by using monoclonal antibodies on the cryostat section of 124 invasive mammary carcinomas. Two patterns of alpha 2 beta 1 immunoreactivity, i.e. pericellular and basolateral, were identified in breast carcinomas and correlated with their histological type. In most invasive ductal carcinomas of no special type (NOS), integrin staining tended to decrease in both pericellular and basolateral aspects. Loss of basolateral staining for alpha 2 beta 1 integrin corresponded closely to the loss of immunoreactivity for collagen IV. Mucinous and medullary carcinomas showed strongly alpha 2 beta 1 pericellular staining, but no basolateral reactivity or collagen IV expression. Only two of the infiltrating lobular carcinomas expressed strong pericellular reactivity. In 82 ductal carcinomas NOS, the abnormally low expression/absence of alpha 2 beta 1 integrin correlated with estrogen and progesterone receptor negativity (p < 0.04 and p < 0.002, respectively). No correlation between integrin expression, histological grade, nodal involvement and proliferative activity was found. The results of the present study suggest that changes in alpha 2 beta 1 expression correlate with the histological type and hormonal receptor status in breast carcinomas. The clinical implications of these findings remain to be elucidated.

Abnormal expression of integrin alpha 6 beta 4 in cervical intraepithelial neoplasia

We have used subunit-specific monoclonal antibodies (MAbs) and immunohistochemistry to examine the distribution of integrin alpha 6 beta 4 in normal ectocervical epithelium and various grades of cervical intraepithelial neoplasia (CIN). Antibodies were first characterised by immunoprecipitation from two surface-labelled tumour cell lines. Monoclonal antibody G71 was found to precipitate integrin beta 4 from BeWo but not T47D cells, while other anti-beta 4 antibodies precipitated beta 4 from both cell lines. Both G71 and an antiserum to the C-terminal peptide of beta 4 precipitated free beta 4 from surface-iodinated BeWo cells. Neither antibody recognised truncated beta 4 chains observed at approximately 160 kDa. These data suggest that different isoforms of beta 4 are expressed in different tumour cell lines, and that there may be a pool of beta 4 at the cell surface that is not complexed to alpha 6. In normal cervix, both the alpha 6 and beta 4 subunits occur at the basal surface of the basal cell layer. In CIN, the distribution is markedly altered, with strong expression of alpha 6 and beta 4 in the upper cell layers of the ectocervical epithelium. All 40 cases of CIN that were studied exhibited this alteration. Furthermore, the extent of extrabasal staining appeared to correspond with the grade of CIN. The form of integrin beta 4 recognised by antibody G71 also appears in the upper cell layers in CIN, but it shows a more restricted distribution than the normal isoform.