Gene expression profile changes correlated with lymph node metastasis in oral squamous cell carcinoma

Integrated computational screening and liquid biopsy approach to uncover the role of biomarkers for oral cancer lymph node metastasis

Cancer is an abnormal, heterogeneous growth of cells with the ability to invade surrounding tissue and even distant organs. Worldwide, GLOBOCAN had an estimated 18.1 million new cases and 9.6 million death rates of cancer in 2018. Among all cancers, Oral cancer (OC) is the sixth most common cancer worldwide, and the third most common in India, the most frequent type, oral squamous cell carcinoma (OSCC), tends to spread to lymph nodes in advanced stages. Throughout the past few decades, the molecular landscape of OSCC biology has remained unknown despite breakthroughs in our understanding of the genome-scale gene expression pattern of oral cancer particularly in lymph node metastasis. Moreover, due to tissue variability in single-cohort studies, investigations on OSCC gene-expression profiles are scarce or inconsistent. The work provides a comprehensive analysis of changed expression and lays a major focus on employing a liquid biopsy base method to find new therapeutic targets and early prediction biomarkers for lymph node metastasis. Therefore, the current study combined the profile information from GSE9844, GSE30784, GSE3524, and GSE2280 cohorts to screen for differentially expressed genes, and then using gene enrichment analysis and protein-protein interaction network design, identified the possible candidate genes and pathways in lymph node metastatic patients. Additionally, the mRNA expression of discovered genes was assessed using real-time PCR, and the Human Protein Atlas database was utilized to determine the protein levels of hub genes in tumor and normal tissues. Angiogenesis was been investigated using the Chorioallentoic membrane (CAM) angiogenesis test. In a cohort of OSCC patients, fibronectin (FN1), C-X-C Motif Chemokine Ligand 8 (CXCL8), and matrix metallopeptidase 9 (MMP9) were significantly upregulated, corroborating these findings. Our identified significant gene signature showed greater serum exosome effectiveness in early detection and clinically linked with intracellular communication in the establishment of the premetastatic niche. Also, the results of the CAM test reveal that primary OC derived exosomes may have a function in angiogenesis. As a result, our study finds three potential genes that may be used as a possible biomarker for lymph node metastasis early detection and sheds light on the underlying processes of exosomes that cause a premetastatic condition.

Systematic analysis of genes involved in oral cancer metastasis to lymph nodes

Oral cancer remains a deadly disease worldwide. Lymph node metastasis and invasion is one of the causes of death from oral cancer. Elucidating the mechanism of oral cancer lymph node metastasis and identifying critical regulatory genes are important for the treatment of this disease. This study aimed to identify differentially expressed genes (gene signature) and pathways that contribute to oral cancer metastasis to lymph nodes. The GSE70604-associated study compared gene profiles in lymph nodes with metastasis of oral cancer to those of normal lymph nodes. The GSE2280-associated study compared gene profiles in primary tumor of oral cancer with lymph node metastasis to those in tumors without lymph node metastasis. There are 28 common differentially expressed genes (DEGs) showing consistent changes in both datasets in overlapping analysis. GO biological process and KEGG pathway analysis of these 28 DEGs identified the gene signature CCND1, JUN and SPP1, which are categorized as key regulatory genes involved in the focal adhesion pathway. Silencing expression of CCND1, JUN and SPP1 in the human oral cancer cell line OECM-1 confirmed that those genes play essential roles in oral cancer cell invasion. Analysis of clinical samples of oral cancer found a strong correlation of these genes with short survival, especially JUN expression associated with metastasis. Our study identified a unique gene signature - CCND1, JUN and SPP1 - which may be involved in oral cancer lymph node metastasis.

Insulin-like growth factor-independent insulin-like growth factor binding protein 3 promotes cell migration and lymph node metastasis of oral squamous cell carcinoma cells by requirement of integrin β1

Frequent metastasis to the cervical lymph nodes leads to poor survival of patients with oral squamous cell carcinoma (OSCC). To understand the underlying mechanisms of lymph node metastasis, two sublines were successfully isolated from cervical lymph nodes of nude mice through in vivo selection, and identified as originating from poorly metastatic parental cells. These two sublines specifically metastasized to cervical lymph nodes in 83% of mice, whereas OEC-M1 cells did not metastasize after injection into the oral cavity. After gene expression analysis, we identified insulin-like growth factor binding protein 3 (IGFBP3) as one of the significantly up-regulated genes in the sublines in comparison with their parental cells. Consistently, meta-analysis of the public microarray datasets and IGFBP3 immunohistochemical analysis revealed increased both levels of IGFBP3 mRNA and protein in human OSCC tissues when compared to normal oral or adjacent nontumorous tissues. Interestingly, the up-regulated IGFBP3 mRNA expression was significantly associated with OSCC patients with lymph node metastasis. IGFBP3 knockdown in the sublines impaired and ectopic IGFBP3 expression in the parental cells promoted migration, transendothelial migration and lymph node metastasis of orthotopic transplantation. Additionally, ectopic expression of IGFBP3 with an IGF-binding defect sustained the IGFBP3-enhanced biological functions. Results indicated that IGFBP3 regulates metastasis-related functions of OSCC cells through an IGF-independent mechanism. Furthermore, exogenous IGFBP3 was sufficient to induce cell motility and extracellular signal-regulated kinase (ERK) activation. The silencing of integrin β1 was able to impair exogenous IGFBP3-mediated migration and ERK phosphorylation, suggesting a critical role of integrin β1 in IGFBP3-enchanced functions.

When will RNA-based tests similar to Oncotype DX be used for oral cancer?

Methods for detection, diagnosis and predicting treatment outcomes for oral squamous cell carcinoma (OSCC) have not changed in decades. Information from studies about molecular changes that occur with these tumors are not useful in the clinic. This is in contrast to breast cancer where global gene expression analysis in the form of the Oncotype DX and Mammaprint tests are used routinely to determine ideal treatment for a large subset of breast tumors. While the first large scale studies of gene expression in both cancer types were done over a dozen years ago, research on OSCC has not led to gene expression profiles that are useful in the clinic. Global gene expression data for well over a thousand breast tumors linked to clinical outcomes has been available online for nearly ten years. This accelerated the development and validation of multiple RNA classifiers used to predict breast cancer treatment outcomes. Molecular characterization of oral and head and neck cancer research has been handicapped primarily due to low sample numbers. The recent release from The Cancer Genome Atlas of global gene expression analyses of over 500 head and neck tumors, including 308 oral tumor samples, obtained by standardized methods, along with linked clinical outcome data, should change this. It makes the vision of including gene expression analysis in OSCC treatment planning an obvious and attainable goal that could occur in the next five years.

Revisiting the transcriptional analysis of primary tumours and associated nodal metastases with enhanced biological and statistical controls: application to thyroid cancer

Background:

Transcriptome profiling has helped characterise nodal spread. The interpretation of these data, however, is not without ambiguities.

Methods:

We profiled the transcriptomes of papillary thyroid cancer nodal metastases, associated primary tumours and primary tumours from N0 patients. We also included patient-matched non-cancerous thyroid and lymph node samples as controls to address some limits of previous studies.

Results:

The transcriptomes of patient-matched primary tumours and metastases were more similar than those of unrelated metastases/primary pairs, as previously reported in other organ systems. This similarity partly reflected patient background. Lymphoid tissues in the metastases confounded the comparison of patient-matched primary tumours and metastases. We circumvented this with an original data adjustment, revealing a differential expression of stroma-related gene signatures also regulated in other organs. The comparison of N0 vs N+ primary tumours uncovered a signal irreproducible across independent data sets. This signal was also detectable when comparing the non-cancerous thyroid tissues adjacent to N0 and N+ tumours, suggesting a cohort-specific bias also likely present in previous similarly sized studies. Classification of N0 vs N+ yielded an accuracy of 63%, but additional statistical controls absent in previous studies revealed that this is explainable by chance alone. We used large data sets from The Cancer Genome Atlas: N0 vs N+ classification was not better than random for most cancers. Yet, it was significant, but of limited accuracy (<70%) for thyroid, breast and head and neck cancers.

Conclusions:

The clinical potential of gene expression to predict nodal metastases seems limited for most cancers.

Increased glucose metabolism by FDG-PET correlates with reduced tumor angiogenesis in oral squamous cell carcinoma

Hypoxia is known to have been related with angiogenesis and glycolysis, and may have an influence on tumor treatment effect. Because glucose utilization is higher in malignant cells than that in normal cells, dynamic glucose metabolism of tumor has been evaluated by means of [(18)F]-fluorodeoxyglucose positron emission tomography (FDG-PET). To investigate the significance of tumor vascularization in oral squamous cell carcinoma, we compared tumor angiogenesis with the FDG-PET findings. Twenty patients underwent FDG-PET. For the quantitative evaluation of FDG uptake in each tumor, the mean standardized uptake value (SUV) was calculated. Microvessel structures labeled with CD34 antigen were investigated in pretreatment biopsy specimens. Using an image analyzer, we calculated the following microvessel parameters: the ratio of the total number of microvessels (TN) to tumor area (TA), the ratio of the total microvessel perimeter (TP) to the TA, and the ratio of the tumor tissue area more than 150 μm distant from each microvessel (hypoxic ratio, %). The SUV was compared with the above parameters. Simple regression analysis revealed a statistical significance between the SUV and the TN:TA ratio (p = 0.046), as well as between the SUV and the TP:TA ratio (p = 0.0206). The SUV was found to be inversely related to the TN:TA and TP:TA ratios. Elevated glucose metabolism assessed by FDG-PET correlated with reduced vascularization. Higher glucose metabolism might therefore reflect a state of hypoxia.

Prognostic significance and tumor biology of regional lymph node disease in patients with rhabdomyosarcoma: a report from the Children's Oncology Group

PURPOSE

Regional lymph node disease (RLND) is a component of the risk-based treatment stratification in rhabdomyosarcoma (RMS). The purpose of this study was to determine the contribution of RLND to prognosis for patients with RMS.

PATIENTS AND METHODS

Patient characteristics and survival outcomes for patients enrolled onto Intergroup Rhabdomyosarcoma Study IV (N = 898, 1991 to 1997) were evaluated among the following three patient groups: nonmetastatic patients with clinical or pathologic negative nodes (N0, 696 patients); patients with clinical or pathologic positive nodes (N1, 125 patients); and patients with a single site of metastatic disease (77 patients).

RESULTS

Outcomes for patients with nonmetastatic alveolar N0 RMS were significantly better than for patients with N1 RMS (5-year failure-free survival [FFS], 73% v 43%, respectively; 5-year overall survival [OS], 80% v 46%, respectively; P < .001). Patients with a single site of alveolar metastasis had even worse FFS and OS (23% FFS and OS, P = .01) when compared with patients with N1 RMS; however, the differences was not as large as the differences between patients with N0 RMS and N1 RMS. For embryonal RMS, there was no statistically significant difference in FFS or OS (P = .41 and P = .77, respectively) for patients with N1 versus N0 RMS. Gene array analysis of primary tumor specimens identified that genes associated with the immune system and antigen presentation were significantly increased in N1 versus N0 alveolar RMS.

CONCLUSION

RLND alters prognosis for alveolar but not embryonal RMS. For patients with N1 disease and alveolar histology, outcomes were more similar to distant metastatic disease rather than local disease. Current data suggest that more aggressive therapy for patients with alveolar N1 RMS may be warranted.

Screen and analysis of key disease genes for precancerous lesions of oral buccal mucosa induced by DMBA in golden hamsters

7,12-Dimethylbenz(a)-anthracene (DMBA)-induced oral buccal mucosa squamous cell carcinoma in Syrian golden hamsters was used to establish precancerous lesions. Agilent rat whole-genome microarray and biological information analysis were used to screen for genes related to key diseases during the transformation of normal buccal mucosa to precancerous lesions in golden hamsters. DMBA acetone solution (0.5%) was used to establish a model of precancerous lesions in oral buccal mucosa in golden hamsters. The results showed that a total of 1331 genes were differentially expressed, including 1278 known, 53 unknown, 747 up-regulated and 584 down-regulated genes. Analysis revealed a total of 14 gene interaction pathways that significantly associated with the 1278 known differentially expressed genes (P<0.05). In conclusion, the occurrence of precancerous lesions in the oral buccal mucosa of golden hamsters was caused by a number of genetic changes that resulted in changes to their respective pathways. Key candidate genes for the formation of precancerous lesions in oral buccal mucosa included Cyp2b13, Orc1L, casp8, CCL5, CXCL12, CCL20, Serping1, P518/Qrfp, F5, TFPI, Vcam1, Fn1, Angpt2, Lcp2, Cxadr, Lyn, Hck, Btk, RGD1564385/fes, Vav1 and IL5ra.

Gene Expression Signatures of Lymph Node Metastasis in Oral Cancer: Molecular Characteristics and Clinical Significances

Even though lymph node metastasis accounts for the vast majority of cancer death in patients with oral cancer (OC), the molecular mechanisms of lymph node metastasis remain elusive. Genome-wide microarray analyses and functional studies in vitro and in vivo, along with detailed clinical observations, have identified a number of molecules that may contribute to lymph node metastasis. These include lymphangionenic cytokines, cell adhesion molecules, basement membrane-interacting molecules, matrix enzymes and relevant downstream signaling pathways. However, defined gene signatures from different studies are highly variable, which hinders their translation to clinically relevant applications. To date, none of the identified signatures or molecular biomarkers has been successfully implemented as a diagnostic or prognostic tool applicable to routine clinical practice. In this review, we will first introduce the significance of lymph node metastasis in OC, and clinical/experimental evidences that support the underlying molecular mechanisms. We will then provide a comprehensive review and integrative analysis of the existing gene expression studies that aim to identify the metastasis-related signatures in OC. Finally, the remaining challenges will be discussed and our insights on future directions will be provided.