Expression and Clinical Significance of Matrix Metalloproteinase-2 and Its Inhibitor TIMP-2 in Oral Squamous Cell Carcinoma

Combined Evaluation of Matrix Metalloproteinases and their Inhibitors has Better Clinical Utility in Oral Cancer

Background

Oral cancer is a major health hazard worldwide with increasing incidence and mortality. Cervical lymph node metastasis is a major determinant of outcome in oral cancer. The matrix metalloproteinase (MMP) system is critically involved in invasion and metastasis. Assessment of MMPs and tissue inhibitors of MMPs (TIMPs) in certain combinations might have better clinical efficacy given their potential role in the metastatic process.

Aim

Plasma concentrations of MMP-2, MMP-9, TIMP-1 and TIMP-2 in 50 controls and 75 oral cancer patients (nonmetastatic, n=54; metastatic, n=21) were evaluated to assess their investigative value and role in predicting the behavior of this malignancy.

Methods

The plasma concentrations of MMP-2, MMP-9, TIMP-1 and TIMP-2 were quantified by ELISA. The best 2- and 3-marker combinations were calculated using the statistical software mROC. The diagnostic values for all the biomolecules as single markers and their combinations were estimated using the measures of diagnostic accuracy, i.e. the area under the ROC curve and the sensitivity and specificity at cutoff limits with the highest diagnostic accuracy and at the 95% limits of sensitivity and specificity, respectively.

Results

MMP-9, TIMP-1 and TIMP-2 were significantly elevated (p=0.000, p=0.013 and p=0.005, respectively) in oral cancer patients. MMP-9 emerged as the best single statistically significant marker in plasma for oral cancer detection. It showed an increase in diagnostic performance when tested in combination with MMP-2 and TIMP-2. The median plasma MMP-9 levels were elevated in both the metastatic and nonmetastatic groups compared with controls (p<0.004 and p<0.007, respectively).

Conclusion

The results indicated that plasma MMP and TIMP levels in relevant combinations may facilitate clinical decision-making for improved management of oral cancer patients and may provide important data for selecting patients for treatment with drugs that interfere with MMP and TIMP activities.

MMP-1/2 and TIMP-1/2 expression levels, and the levels of collagenous and elastic fibers correlate with disease progression in a hamster model of tongue cancer

In the present study, the presence of extracellular matrix components, including collagenous and elastic fibers, and the expression of their key regulating enzymes, were investigated in different stages of hamster tongue carcinoma development. Immunohistochemical and computer-assisted morphological analyses were performed to quantify the staining intensity and area (integral optical density) of matrix metalloproteinase (MMP)-1 and -2, tissue inhibitors of metalloproteinase (TIMP)-1 and -2, and the extent of elastic and collagenous fibers in histological sections. MMP-1, MMP-2, TIMP-1 and TIMP-2 expression levels gradually increased with tongue cancer progression, and were associated with disease pathology staging (r=0.705, 0.633, 0.759 and 0.751, respectively). By contrast, elastic fiber levels gradually decreased with cancer progression and were negatively correlated with disease staging (r=-0.881). The levels of collagenous fibers gradually increased with cancer progression and showed a positive correlation (r=0.619). In summary, the study demonstrated that MMP1/2 and TIMP1/2 expression levels, and collagenous and elastic fiber levels were significantly correlated with disease progression in a hamster model of tongue cancer.

The role of MMP-2 and MMP-9 as prognostic markers in the early stages of tongue squamous cell carcinoma

BACKGROUND

Tongue cancer is the most common intra-oral malignancy with a high rate of morbidity and mortality owing to its increased propensity for tumor invasion and metastasis. These processes require a controlled degradation of the extracellular matrix. Matrix Metalloproteinase-2 (MMP-2) and Matrix Metalloproteinase-9 (MMP-9) are known to be important regulators of matrix lysis and play a significant role in the metastasis of malignancies.

AIM AND OBJECTIVES

To study the expression of MMP-2 and MMP-9 in the early stages of tongue squamous cell carcinoma and find the association between their expression and local recurrence, metastasis, and survival rates of the subjects.

MATERIALS AND METHODS

Fifty-nine tumor biopsy samples of tongue squamous cell carcinoma in T1 N0 M0 and T2 N0 M0 stages were immunostained with MMP-2 and MMP-9 antibodies. The immunohistochemical expression was compared with the patient characteristics and outcome.

RESULTS

Cytoplasmic expression of MMP-2 correlated with that of MMP-9 (r = 0.716, P < 0.001). Greater expression of MMP-2 and MMP-9 was observed in patients who subsequently developed local recurrence (P = 0.044 and P < 0.001, respectively), regional and/or distant metastasis (P < 0.001 and P = 0.001, respectively) of the tumor. Further, a higher expression of these biomarkers was associated with shorter survival. MMP-9 was found to have better specificity for local recurrence, metastasis and survival.

CONCLUSION

Our results showed that these biomarkers may serve as indicators of a patient's risk potential for poor prognosis and presage the need for more aggressive treatment measures.

Oral cancer secretome: identification of cancer-associated proteins

This study aims to identify cancer-associated proteins in the secretome of oral cancer cell lines. We have successfully established four primary cell cultures of normal cells with a limited lifespan without human telomerase reverse transcriptase (hTERT) immortalization. The secretome of these primary cell cultures were compared with that of oral cancer cell lines using 2DE. Thirty five protein spots were found to have changed in abundance. Unambiguous identification of these proteins was achieved by MALDI TOF/TOF. In silico analysis predicted that 24 of these proteins were secreted via classical or nonclassical mechanisms. The mRNA expression of six genes was found to correlate with the corresponding protein abundance. Ingenuity Pathway Analysis (IPA) core analysis revealed that the identified proteins were relevant in, and related to, cancer development with likely involvements in tumor growth, metastasis, hyperproliferation, tumorigenesis, neoplasia, hyperplasia, and cell transformation. In conclusion, we have demonstrated that a comparative study of the secretome of cancer versus normal cell lines can be used to identify cancer-associated proteins.

Matrix metalloproteinases and their inhibitors: correlation with invasion and metastasis in oral cancer

Matrix metalloproteinases (MMPs) have been implicated in invasion and metastasis of various malignancies. The study evaluated a comprehensive profile of MMP-2 and MMP-9 and their inhibitors, tissue inhibitor of metalloproteinases-2 (TIMP-2) and tissue inhibitor of metalloproteinases-1 (TIMP-1), respectively in 50 controls and 75 patients with oral squamous cell carcinoma (OSCC). Blood samples from controls and patients as well as malignant and adjacent normal tissues from the patients were collected. The study examined pro, active and total forms of MMP-2 and MMP-9 using zymography. Enzyme-linked immunoassay (ELISA) and reverse transcription polymerase chain reaction were carried out to evaluate protein levels and mRNA expression; respectively, for the MMPs and TIMPs. Plasma pro, active and total MMP-2, MMP-9 as well as TIMP-1 and TIMP-2 levels were significantly higher in oral cancer patients as compared to the controls. mRNA expression of the MMPs and TIMPs was significantly higher in malignant tissues as compared to adjacent normal tissues. A significant positive correlation was observed between levels of proMMP-9 and active MMP-9 with differentiation, stage and infiltration. ProMMP-2 and active MMP-2 exhibited significant positive correlation with differentiation and lymph node involvement. The multivariate analysis of ELISA results revealed a significant positive correlation between MMP-2, TIMP-1 and TIMP-2 levels with lymph node involvement, stage and differentiation. The receiver operating characteristic curve (ROC) analysis showed that the levels of MMPs and TIMPs have significant discriminatory efficacy to differentiate between controls and patients. The results indicate that MMP-2, MMP-9, TIMP-1 and TIMP-2 have significant clinical usefulness for oral cancer patients. Zymographic analysis is a simple, cost effective, rapid and sensitive alternative assay.