Relation between laminin-5 gamma 2 chain and cell surface metalloproteinase MT1-MMP in clear cell carcinoma of the ovary

The role of MMP-14 in ovarian cancer: a systematic review

AIM

In order to evaluate the role of MMP-14 in ovarian cancer, a systematic review was conducted.

METHODS

In March 2020, a search in Pubmed was performed with MMP-14 and ovarian cancer as search terms. After exclusion of the references not on MMP-14 or ovarian cancer or not in English, the studies found were classified into two categories: basic research and clinicopathological research.

RESULTS

In total, 94 references were found of which 33 were excluded. Two additional articles were found in the reference lists of the included studies. Based on the full texts, another 4 were excluded. Eventually, 59 studies were included in the review, 32 on basic research and 19 on clinicopathological research. 8 studies fell in both categories. The basic research studies show that MMP-14 plays an important role in ovarian cancer in the processes of proliferation, invasion, angiogenesis and metastasis. In clinocopathological research, MMP-14 expression is found in most tumours with characteristics of poor prognosis but this immunohistochemical MMP-14 determination does not seem to be an independent predictor of prognosis.

CONCLUSIONS

From this systematic review of the literature concerning MMP-14 in ovarian cancer it becomes clear that MMP-14 plays various important roles in the pathophysiology of ovarian cancer. The exact translation of these roles in the pathophysiology to the importance of MMP-14 in clinicopathological research in ovarian cancer and possible therapeutic role of anti-MMP-14 agents needs further elucidation.

Pathology of clear cell carcinoma of the ovary: A basic view based on cultured cells and modern view from comprehensive approaches

Clear cell carcinoma (CCC) is a distinct histologic type of ovarian carcinoma. CCC is more frequent in Japan than in the Western world. CCC is chemo-resistant and often associated with paraneoplastic thromboembolism. Histologically, CCC is characterized by both cancer cells and stromas, being concordant with the cytological features. Clear cells contain abundant glycogen. Hepatocyte nuclear factor-1β is a specific marker of CCC, and is likely to be involved in glucose metabolism. Extracellular matrix (ECM)-deposited stroma and plasma cell-rich inflammatory stroma are characteristic stromas of CCC. Studies using CCC cell lines showed that CCC cells produce ECMs and stimulate plasma cell differentiation in a paracrine manner. Most CCCs, as well as endometrioid carcinomas, originate from ovarian endometriosis. This is supported by molecular genetic data, although it remains unclear why different histologic types originate from the same precursor. CCC and endometrioid carcinoma are Lynch syndrome-associated ovarian carcinomas. Recent comprehensive studies indicate that CCC is distinct not only in terms of histology but also in genomics, epigenomics and transcriptomics. This review summarizes the pathology of ovarian CCC along with a basic view based on cultured cells, and refers to recent genetic and omic data.

LAMC2 regulated by microRNA-125a-5p accelerates the progression of ovarian cancer via activating p38 MAPK signalling

AIMS

Laminin γ2 (LAMC2) is over-expressed in ovarian cancer, and its high expression facilitates cell invasion. Nevertheless, the effects of LAMC2 on other ovarian cancer cell functions and its underlying mechanism remain largely unclear. Bioinformatics analysis shows that LAMC2 is a predicted target of miR-125a-5p and miR-193a-3p. Therefore, the present study aimed to investigate the effects of LAMC2 in ovarian cancer progression and determine whether LAMC2 expression is under the regulation of miR-125a-5p or miR-193a-3p in ovarian cancer.

MATERIALS AND METHODS

Immunohistochemistry staining, western blot and qPCR were used to detect LAMC2 expression profiles. CCK-8, flow cytometry and tumour formation assays were used to assess cell proliferation, apoptosis and tumorigenesis. The interaction between miR-125a-5p/miR-193a-3p and LAMC2 were determined by the luciferase gene reporter assay.

KEY FINDINGS

The results showed that LAMC2 was over-expressed in ovarian cancer tissues and cell lines. Over-expression of LAMC2 significantly promoted cell proliferation and repressed cell apoptosis, as well as increased the expression levels of p38, p-p38, c-myc and CREB, and translocated p38 protein to the nucleus. In addition, the promotion of cell proliferation and repression of cell apoptosis mediated by LAMC2 over-expression were all weakened when p38 was downregulated. Moreover, LAMC2 expression was negatively regulated by miR-125a-5p, which inhibited the nuclear accumulation of p38 protein. Upregulation of LAMC2 significantly abolished the effects of miR-125a-5p on cell proliferation inhibition and cell apoptosis promotion, as well as tumourigenesis repression.

SIGNIFICANCE

The present study clarified that LAMC2 functioned as an oncogene in ovarian cancer through upregulating p38 under the regulation of miR-125a-5p.

The role of the tumor stroma in ovarian cancer

The tumor microenvironment, consisting of stromal myofibroblasts, endothelial cells, and leukocytes, is growingly perceived to be a major contributor to the pathogenesis and disease progression in practically all cancer types. Stromal myofibroblasts produce angiogenic factors, proteases, growth factors, immune response-modulating proteins, anti-apoptotic proteins, and signaling molecules, and express surface receptors and respond to stimuli initiated in the tumor cells to establish a bi-directional communication network in the microenvironment to promote tumor cell invasion and metastasis. Many of these molecules are candidates for targeted therapy and the cancer stroma has been recently regarded as target for biological intervention. This review provides an overview of the biology and clinical role of the stroma in ovarian cancer.

Broad coverage identification of multiple proteolytic cleavage site sequences in complex high molecular weight proteins using quantitative proteomics as a complement to edman sequencing

Proteolytic processing modifies the pleiotropic functions of many large, complex, and modular proteins and can generate cleavage products with new biological activity. The identification of exact proteolytic cleavage sites in the extracellular matrix laminins, fibronectin, and other extracellular matrix proteins is not only important for understanding protein turnover but is needed for the identification of new bioactive cleavage products. Several such products have recently been recognized that are suggested to play important cellular regulatory roles in processes, including angiogenesis. However, identifying multiple cleavage sites in extracellular matrix proteins and other large proteins is challenging as N-terminal Edman sequencing of multiple and often closely spaced cleavage fragments on SDS-PAGE gels is difficult, thus limiting throughput and coverage. We developed a new liquid chromatography-mass spectrometry approach we call amino-terminal oriented mass spectrometry of substrates (ATOMS) for the N-terminal identification of protein cleavage fragments in solution. ATOMS utilizes efficient and low cost dimethylation isotopic labeling of original N-terminal and proteolytically generated N termini of protein cleavage fragments followed by quantitative tandem mass spectrometry analysis. Being a peptide-centric approach, ATOMS is not dependent on the SDS-PAGE resolution limits for protein fragments of similar mass. We demonstrate that ATOMS reliably identifies multiple proteolytic sites per reaction in complex proteins. Fifty-five neutrophil elastase cleavage sites were identified in laminin-1 and fibronectin-1 with 34 more identified by matrix metalloproteinase cleavage. Hence, our degradomics approach offers a complimentary alternative to Edman sequencing with broad applicability in identifying N termini such as cleavage sites in complex high molecular weight extracellular matrix proteins after in vitro cleavage assays. ATOMS can therefore be useful in identifying new cleavage products of extracellular matrix proteins cleaved by proteases in pathology for bioactivity screening.

Alternate mucoid and hyalinized stroma in clear cell carcinoma of the ovary: manifestation of serial stromal remodeling

The stroma in ovarian clear cell carcinoma often shows alternate mucoid and hyalinized change. The hyalinized stroma is recognized to be an aberrant deposition of basement membrane material produced by tumor cells. The mucoid stroma, however, has drawn far less attention, and its significance remains unclear. We examined 60 ovarian clear cell carcinomas for the distribution and nature of the mucoid stroma. For comparison, 125 other surface epithelial ovarian tumors were examined. Twenty-nine of 60 (48%) clear cell carcinomas showed a mucoid stroma, either focally (21 cases) or diffusely (8 cases). The mucoid stroma in clear cell carcinomas was distinct from that in other surface epithelial tumors as follows: it showed a compact spherule-like appearance, commonly occupying the cores of small papillae. It also exhibited a cribriform pattern, resembling that of adenoid cystic carcinoma. It was rarely associated with stromal cells, despite the presence of abundant glycosaminoglycan including hyaluronan. Alternatively, it was strongly associated with hyalinized stroma. Among 40 clear cell carcinomas that had at least one type of stroma, 26 (65%) had both, either concomitantly or separately. The mucoid stroma tended to attenuate if the hyalinized stroma developed. In vitro, a clear cell carcinoma cell line, HAC-2, formed a spherule-like structure containing hyaluronan in the center, and a significant amount of hyaluronan was detected by latex agglutination immunoturbidimetry, indicating that HAC-2 itself has the potential to produce hyaluronan. All of these facts indicate that the spherule-like mucoid stroma and hyalinized stroma represent different phases of the stromal remodeling process, which is promoted by the deposition of different extracellular matrices produced by clear cell carcinoma cells. The spherule-like mucoid stroma and hyalinized stroma are considered complementary diagnostic signatures of ovarian clear cell carcinoma.

Neurotrophin NT3 promotes ovarian primordial to primary follicle transition

Neurotrophins are growth factors that are known to have a role in promoting cell survival and differentiation. The focus of the current study is to examine the role of neurotrophins in regulating ovarian primordial follicle development. Ovaries from 4-day old rats were placed into organ culture and cultured for 10 days in the absence or presence of neurotrophin-3 (NT3), brain-derived neurotrophic factor (BDNF), or nerve growth factor (NGF). Treatment of ovaries with NT3 resulted in a significant (P<0.01) increase in primordial follicle development (i.e. primordial to primary follicle transition). Treatment with BDNF at high doses of 100-250 ng/ml also significantly (P<0.01) increased primordial follicle development, but NGF had no effect. Immunohistochemical studies determined that NT3 was present in granulosa cells, interstitial tissue, and in the oocytes of primordial and primary follicles. The NT3 receptor NTRK3 was present in oocytes at all stages of development. Analysis of ovaries that contain predominantly primordial follicles demonstrated the transcripts for NT3, NTRK3, NGF, and the BDNF/neurotrophin-4 (NT4) receptor NTRK2 are expressed, while BDNF, NT4, and the NGF receptor NTRK1 are not detectable. Inhibition of the NTRK3 receptor with the tyrphostin AG 879 resulted in oocyte death and a significant (P<0.01) reduction in follicle pool size. Inhibition of the NTRK receptors with K252a slowed primordial to primary follicle transition. A microarray analysis demonstrated that a small number of genes were differentially expressed after NT3 treatment. Observations indicate that the neurotrophin NT3, acting through the NTRK3 receptor in oocytes, promotes the primordial to primary follicle transition.