A role for aberrantly expressed nuclear localized decorin in migration and invasion of dysplastic and malignant oral epithelial cells

A crossroad between placental and tumor biology: What have we learnt?

Placenta in certain species including the human has evolved as a highly invasive tumor-like organ invading the uterus aned its vasculature to derive oxygen and nutrients for the fetus and exchange waste products. While several excellent reviews have been written comparing hemochorial placentation with tumors, no comprehensive review is available dealing with mechanistic insights into what makes them different, and what tumor biologists can learn from placental biologists, and vice versa. In this review, we analyze the structure-function relationship of the human placenta, emphasizing the functional need of the spatio-temporally orchestrated trophoblast invasiveness for fetal development and growth, and pathological consequences of aberrant invasiveness for fetal and maternal health. We then analyze similarities and differences between the placenta and invasive tumors in terms of hallmarks of cancer, some key molecules regulating their invasive functions, and how placental cancers (choriocarcinomas) or other cancers become refractory or even addicted to these invasion-restraining molecules. We cite in vitro models of human trophoblast and choriocarcinoma cell lines utilized to study mechanisms in normal placental development as well as those responsible for tumor progression. We discuss the pathobiology of hyper-invasive placentas and show thattrophoblastic neoplasias are a unique and heterogeneous class of tumors. We delve into the questions as to why metastasis from other organs rarely occurs at the placental site and whether pregnancy makes the mother more or less vulnerable to cancer-related morbidity/mortality. We attempt to compare trophoblast stem cells and cancer stem cells. Finally, we leave the readers with some thoughts as foods of future investigations.

Differential in vitro sensitivity of oral precancerous and squamous cell carcinoma cell lines to 5-aminolevulinic acid-mediated photodynamic therapy

OBJECTIVES

The clinical effect of 5-aminolevulinic acid-mediated photodynamic therapy (ALA-PDT) may be correlated with the degree of dysplasia of cancer tissues, but much is still unknown regarding the differences in its effectiveness, especially in oral cancer and precancerous lesions. The aim of this study is to compare the effects of ALA-PDT on a human oral precancerous cell line (DOK) and an oral squamous cell carcinoma cell line (CAL-27).

METHODS

First, we explored the dose- and time-dependent responses of DOK and CAL-27 cells to ALA-PDT. DOK and CAL-27 cells were incubated with various concentrations of ALA (from 0.25 to 2 mM), followed by PDT using laser irradiation at 635 nm. The resulting photocytotoxicity was assessed in both cell lines using MTT assays. Further, apoptosis was assessed using flow cytometry, reactive oxygen species (ROS) generation was evaluated with 2,7-dichlorofluorescein diacetate (DCFH2-DA), and the response to treatment was examined via RT-qPCR and Western blotting to measure the mRNA and protein expression levels of matrix metallopeptidase 2 (MMP-2) and MMP-9.

RESULTS

ALA-PDT inhibited the proliferation of DOK and CAL-27 cells in a dose- and time-dependent manner. Dose-effect and inhibition-time relationships were also found. The rates of DOK and CAL-27 cell apoptosis when the ALA dose was 1 mM were 30.66 ± 3.10% and 75.40 ± 1.29%, respectively (P < 0.01). Following PDT, compared with DOK cells, the ROS level in CAL-27 cells was significantly increased and was correlated with an increase in the ALA concentration. Mechanistically, both the mRNA and protein expression levels of MMP-2 and MMP-9 were found to be regulated in both cell types after ALA-PDT.

CONCLUSION

ALA-PDT effectively killed DOK and CAL-27 cells in a dose- and time-dependent manner in vitro. However, under the same conditions, the susceptibilities of these cell lines to ALA-PDT were different. Further studies are necessary to confirm whether this difference is present in clinical oral cancer and precancerous lesions.

P-cadherin-induced decorin secretion is required for collagen fiber alignment and directional collective cell migration

Directional collective cell migration (DCCM) is crucial for morphogenesis and cancer metastasis. P-cadherin (also known as CDH3), which is a cell-cell adhesion protein expressed in carcinoma and aggressive sarcoma cells and associated with poor prognosis, is a major DCCM regulator. However, it is unclear how P-cadherin-mediated mechanical coupling between migrating cells influences force transmission to the extracellular matrix (ECM). Here, we found that decorin, a small proteoglycan that binds to and organizes collagen fibers, is specifically expressed and secreted upon P-cadherin, but not E- and R-cadherin (also known as CDH1 and CDH4, respectively) expression. Through cell biological and biophysical approaches, we demonstrated that decorin is required for P-cadherin-mediated DCCM and collagen fiber orientation in the migration direction in 2D and 3D matrices. Moreover, P-cadherin, through decorin-mediated collagen fiber reorientation, promotes the activation of β1 integrin and of the β-Pix (ARHGEF7)/CDC42 axis, which increases traction forces, allowing DCCM. Our results identify a novel P-cadherin-mediated mechanism to promote DCCM through ECM remodeling and ECM-guided cell migration.

Enhanced metastatic potential in the MB49 urothelial carcinoma model

Recent data suggest that patients with a basal/stem-like bladder cancer (BC) subtype tend to have metastatic disease, but this is unconfirmed. Here we report the identification of murine MB49 cell line sub-clones with stem-like characteristics in culture. Subcutaneous implantation of S2 and S4 MB49 sub-clones into immunocompetent mice resulted in lung metastases in 50% and 80% of mice respectively, whereas none of the mice implanted with the parental cells developed metastasis. Gene profiling of cells cultured from S2 and S4 primary and metastatic tumors revealed that a panel of genes with basal/stem-like/EMT properties is amplified during metastatic progression. Among them, ITGB1, TWIST1 and KRT6B are consistently up-regulated in metastatic tumors of both MB49 sub-clones. To evaluate clinical relevance, we examined these genes in a human public dataset and found that ITGB1 and KRT6B expression in BC patient tumor samples are positively correlated with tumor grade. Likewise, the expression levels of these three genes are correlated with worse clinical outcomes. This MB49 BC metastatic pre-clinical model provides a unique opportunity to validate and recapitulate results discovered in patient studies and to pursue future mechanistic therapeutic interventions for BC metastasis.

Insider trading: Extracellular matrix proteins and their non-canonical intracellular roles

In metazoans, the extracellular matrix (ECM) provides a dynamic, heterogeneous microenvironment that has important supportive and instructive roles. Although the primary site of action of ECM proteins is extracellular, evidence is emerging for non-canonical intracellular roles. Examples include osteopontin, thrombospondins, IGF-binding protein 3 and biglycan, and relate to roles in transcription, cell-stress responses, autophagy and cancer. These findings pose conceptual problems on how proteins signalled for secretion can be routed to the cytosol or nucleus, or can function in environments with diverse redox, pH and ionic conditions. We review evidence for intracellular locations and functions of ECM proteins, and current knowledge of the mechanisms by which they may enter intracellular compartments. We evaluate the experimental methods that are appropriate to obtain rigorous evidence for intracellular localisation and function. Better insight into this under-researched topic is needed to decipher the complete spectrum of physiological and pathological roles of ECM proteins.

Deregulation of decorin and FHL1 are associated with esophageal squamous cell carcinoma progression and poor prognosis

To investigate the expression of FHL1 and Decorin in esophageal squamous cell carcinoma (ESCC) and its clinical significance. 82 ESCC tissues were evaluated by immunohistochemistry for the expression of FHL1 and Decorin. The role of the expression of FHL1 and Decorin in ESCC were statistically analyzed. The expression level of FHL1 and Decorin were reduced in malignant tissue samples in comparison to normal matched tissue (P < 0.05). It was also proved that the positive expressions of FHL1 and Decorin were associated with ESCC histological grade, lymph node metastasis, tumor stage and clinical stage (P < 0.05). In addition, the Kaplan-Meier survival curves revealed that the positive expressions of FHL1 and Decorin were associated with favorable prognosis in ESCC patients. Multivariate analysis showed that the positive expressions of FHL1 and Decorin were independent prognostic markers of overall survival of ESCC patients, respectively. The positive expressions of FHL1 and Decorin were associated with ESCC progression and good prognosis. Our results indicate that the positive expressions of FHL1 and Decorin were independent prognostic factors for patients with esophageal cancer, which might be potential valuable biomarkers for ESCC.

Microenvironmental Modulation of Decorin and Lumican in Temozolomide-Resistant Glioblastoma and Neuroblastoma Cancer Stem-Like Cells

The presence of cancer stem cells (CSCs) or tumor-initiating cells can lead to cancer recurrence in a permissive cell–microenvironment interplay, promoting invasion in glioblastoma (GBM) and neuroblastoma (NB). Extracellular matrix (ECM) small leucine-rich proteoglycans (SLRPs) play multiple roles in tissue homeostasis by remodeling the extracellular matrix (ECM) components and modulating intracellular signaling pathways. Due to their pan-inhibitory properties against receptor tyrosine kinases (RTKs), SLRPs are reported to exert anticancer effects in vitro and in vivo. However, their roles seem to be tissue-specific and they are also involved in cancer cell migration and drug resistance, paving the way to complex different scenarios. The aim of this study was to determine whether the SLRPs decorin (DCN) and lumican (LUM) are recruited in cell plasticity and microenvironmental adaptation of differentiated cancer cells induced towards stem-like phenotype. Floating neurospheres were generated by applying CSC enrichment medium (neural stem cell serum-free medium, NSC SFM) to the established SF-268 and SK-N-SH cancer cell lines, cellular models of GBM and NB, respectively. In both models, the time-dependent synergistic activation of DCN and LUM was observed. The highest DCN and LUM mRNA/protein expression was detected after cell exposure to NSC SFM for 8/12 days, considering these cells as SLRP-expressing (SLRP⁺) CSC-like. Ultrastructural imaging showed the cellular heterogeneity of both the GBM and NB neurospheres and identified the inner living cells. Parental cell lines of both GBM and NB grew only in soft agar + NSC SFM, whereas the secondary neurospheres (originated from SLRP⁺ t₈ CSC-like) showed lower proliferation rates than primary neurospheres. Interestingly, the SLRP⁺ CSC-like from the GBM and NB neurospheres were resistant to temozolomide (TMZ) at concentrations >750 μM. Our results suggest that GBM and NB CSC-like promote the activation of huge quantities of SLRP in response to CSC enrichment, simultaneously acquiring TMZ resistance, cellular heterogeneity, and a quiescent phenotype, suggesting a novel pivotal role for SLRP in drug resistance and cell plasticity of CSC-like, allowing cell survival and ECM/niche modulation potential.

Decorin is responsible for progression of non-small-cell lung cancer by promoting cell proliferation and metastasis

Decorin, a member of the small leucine-rich proteoglycans family, exists and plays multifunctional roles in stromal and epithelial cells. Emerging evidences showed that decorin is dysregulated expression in a wide variety of human tumors and affects a broad biology process of cancer cells, including growth, metastasis, and angiogenesis. Recent studies demonstrated that decorin could affect A549 proliferation though decreasing TGF-β1, cycling D1 expression and increasing P53 and P21 expression. However, limited data are available on the effect of decorin on metastasis of non-small-cell lung cancer (NSCLC) cell lines and how decorin impacts metastasis is still unknown. In this study, we identified decorin mRNA expression through Oncomine database and verified the expression of decorin mRNA and protein in 50 patients who underwent primary surgical resection of a NSCLC in the Department of Thoracic Surgery, Jinling Hospital, Nanjing University School of Medicine, China, between September 2013 and March 2014 by quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) and Western blot. Also, the correlationship between decorin and the NSCLC patients' clinical characteristics or survival ( www.kmplot.com ) was analyzed. Via ectopic expression analyses and Western blot, the roles of decorin in proliferation, metastasis, and the underline mechanism for decorin expression were further explored. We found that decorin was downregulated in NSCLC tissues compared with the adjacent normal lung tissues or normal tissues. Additionally, the expression of decorin was correlated with tumor size, lymph node metastasis, tumor stage, and prognosis. We also showed that overexpression of decorin could inhibit NSCLC cell lines proliferation and metastasis. Through Western blot analysis, we identified that E-cadherin and vascular endothelial growth factor (VEGF) are two key factors responsible for the growth arrest and metastasis inhibition induced by decorin in NSCLC. Our results indicated that decorin plays crucial roles in NSCLC against carcinogenesis and progression. Decorin might be a predictive factor and an attractive therapeutic target for NSCLC patients.

An essential role for decorin in bladder cancer invasiveness

Muscle-invasive forms of urothelial carcinomas are responsible for most mortality in bladder cancer. Finding new treatments for invasive bladder tumours requires adequate animal models to decipher the mechanisms of progression, in particular the way tumours interact with their microenvironment. Herein, using the murine bladder tumour cell line MB49 and its more aggressive variant MB49-I, we demonstrate that the adaptive immune system efficiently limits progression of MB49, whereas MB49-I has lost tumour antigens and is insensitive to adaptive immune responses. Furthermore, we unravel a parallel mechanism developed by MB49-I to subvert its environment: de novo secretion of the proteoglycan decorin. We show that decorin overexpression in the MB49/MB49-I model is required for efficient progression, by promoting angiogenesis and tumour cell invasiveness. Finally, we show that these results are relevant to muscle-invasive human bladder carcinomas, which overexpress decorin together with angiogenesis- and adhesion/migration-related genes, and that decorin overexpression in the human bladder carcinoma cell line TCCSUP is required for efficient invasiveness in vitro. We thus propose decorin as a new therapeutic target for these aggressive tumours.

Opticin, a small leucine-rich proteoglycan, is uniquely expressed and translocated to the nucleus of chronic lymphocytic leukemia cells

Background

Opticin (OPTC) is a member of the small leucine-rich proteoglycan (SLRP) family and is localized particularly in certain extracellular matrices. We have previously reported the unique expression of another SLRP, fibromodulin (FMOD) in the leukemic cells of patients with chronic lymphocytic leukemia (CLL). OPTC is located in the same region as FMOD on chromosome 1 (1q32.1). Cluster up-regulation of genes may be observed in malignancies and the aim of the present study was to analyze the expression of OPTC in CLL cells.

Methods

The expression of OPTC was tested by RT-PCR and realtime qPCR in PBMC from CLL patients, other hematological malignancies and healthy controls. The presence of OPTC protein, and its subcellular localization, was investigated using fractionation methods where the obtained lysate fractions were analyzed by Western blotting. Deglycosylation experiments were performed to investigate the glycosylation status of the CLL OPTC.

Results

OPTC was expressed at the gene level in all patients with CLL (n = 90) and in 2/8 patients with mantle cell lymphoma (MCL) but not in blood mononuclear cells of healthy control donors (n = 20) or in tumor samples from nine other types of hematological malignancies. OPTC was detected by Western blot in all CLL samples analyzed (n = 30) but not in normal leukocytes (n = 10). Further analysis revealed a CLL-unique unglycosylated 37 kDa core protein that was found to be located preferentially in the cell nucleus and endoplasmic reticulum (ER) of the CLL cells.

Conclusions

A 37 kDa unglycosylated OPTC protein was detected in ER and in the nucleus of CLL cells and not in healthy control donors. The function of this OPTC core protein remains unclear but its CLL-specific expression and subcellular localization warrants further investigations in the pathobiology of CLL.

Knockdown of aberrantly expressed nuclear localized decorin attenuates tumour angiogenesis related mediators in oral cancer progression model in vitro

Background

Oral cancer accounts for roughly 3% of cancer cases in the world with about 350,000 newly reported cases annually and a 5-year survival rate of only 50%. Majority of oral cancers are squamous cell carcinomas that originate in the oral mucosal epithelial linings. We have previously shown that in human malignant squamous cells carcinoma (SCC-25) as well as in dysplastic oral keratinocytes (DOK), a small leucine-rich multifunctional proteoglycan decorin is aberrantly expressed and localized in the nucleus where it interacts with nuclear epidermal growth factor receptor (EGFR). Post-transcriptional silencing of nuclear decorin significantly reduced IL-8 and IL8-dependent migration and invasion in these dysplastic and malignant oral epithelia. The objective of this study was to further examine the effects of nuclear decorin silencing on angiogenesis and angiogenesis related mediators in this oral cancer progression cell line model.

Methods

We have used multiplex PCR, western blotting, and in vitro endothelial tube formation assay to study angiogenesis and related pathways in nuclear decorin silenced (stable knockdown) DOK and SCC-25 cells.

Results

Nuclear decorin knockdown resulted in significant down regulation of IL-8 expression, however IL-10, and TGF-β expression was not affected in either DOK or SCC25 cells as measured by multiplex RT PCR. IL-8 receptor CXCR 1 and 2 expression was slightly lower in nuclear decorin silenced cells indicating a contributing mechanism in previously shown reduced IL-8 mediated migration and invasion phenotype in these cells. IL-8 is known to induce Matrix metalloproteinase 9 (MMP9) which not only plays a role in tumour migration and invasion but also induces angiogenic switch. We found MMP9 to be significantly reduced in nuclear decorin silenced dysplastic and malignant oral epithelia. Other potent angiogenic mediators, VEGF₁₈₉ and ANG-1 were either significantly reduced or completely abrogated in these cells. Angiogenesis as measured by endothelial tube-like formations of HUVEC cells was reduced by almost 50 percent when HUVECs were incubated in the presence of conditioned medium form nuclear decorin silenced dysplastic and malignant cell lines as compared to respective controls.

Conclusions

Together these results indicate that aberrantly expressed nuclear localized decorin strongly influences angiogenic potential of dysplastic and malignant oral epithelial cells.