CDC28 protein kinase regulatory subunit 1B (CKS1B) expression and genetic status analysis in oral squamous cell carcinoma

Identification of Biomarkers Associated with Cancerous Change in Oral Leukoplakia Based on Integrated Transcriptome Analysis

Objective

Oral leukoplakia (OLK) is the most common precancerous lesion in the oral cavity. This study aimed to explore key biomarkers for monitoring OLK for early diagnosis of oral squamous cell carcinoma (OSCC) and screen small-molecule drugs for the prevention of OSCC.

Method

The Gene Expression Omnibus (GEO) database was explored to extract two microarray datasets, namely, GSE85195 and GSE25099. The data of the normal group, OLK group, and OSCC group were analyzed by weighted gene coexpression network analysis (WGCNA) to identify the most significant gene module and differentially expressed genes (DEGs). The intersection genes were extracted as the key genes of OLK carcinogenesis. Subsequently, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were analyzed in the module. Connectivity Map and molecular docking were used to screen small-molecule drugs. The diagnostic values of four key genes were identified and verified in the GSE26549 dataset.

Results

WGCNA obtained the red module (r = −0.91, p < 0.05) with the strongest correlation with cancerous phenotype. GO enrichment analysis showed 60 pathways, including 28 biological processes, 11 cell components, and 21 molecular functions, and KEGG enrichment analysis showed 4 pathways (p < 0.05). In the differential expression analysis, there was no intersection between the upregulated genes and the red module genes. However, the intersection of the downregulated genes and the red module genes yielded 4 key genes: dopachrome tautomerase (DCT), keratin 3 (KRT3), keratin 76 (KRT76), and FAM3 metabolic regulation signal molecule B (FAM3B). The area under the curve of the diagnostic model constructed by these four genes was 0.963 (CI = 0.913–1.000). The sensitivity was 0.933, and the specificity was 0.923. The diagnostic model was successfully verified in GSE26549 (AUC = 0.745, CI = 0.638–0.851). Compared with the diagnostic models of the previous studies, the diagnostic efficiency of this model was the highest. The small-molecule drugs, selumetinib and benidipine, were selected according to the gene expression profile and showed binding activity when docking with the above molecules.

Conclusions

This study provides new targets and drugs for OLK. These targets could be used as the key diagnostic molecules for long-term follow-up of OLK. The small-molecule drugs selumetinib and benidipine could be used for the prevention and treatment of OSCC.

CKS1B promotes cell proliferation and invasion by activating STAT3/PD-L1 and phosphorylation of Akt signaling in papillary thyroid carcinoma

Objective

To investigate role of GKS1B and its relationship between STAT3/PD‐L1 and p‐Akt in papillary thyroid carcinoma (PTC).

Methods

Expression of GKS1B and PD‐L1 was determined in PTC cell lines. GKS1B was overexpressed or knocked down by transfection with overexpression plasmids or si‐CKS1B. STAT3 inhibitor WP1066 was used to suppress STAT3, and PD‐L1 inhibitor Pembrolizumab was used to block PD‐L1. Cell viability and invasion were evaluated by MTT and transwell assay, respectively. The expression of STAT3, p‐STAT3, Akt, and p‐Akt was measured using Western blotting.

Results

Both protein levels and mRNA levels of CKS1B and PD‐L1 were remarkably up‐regulated in PTC cell lines. Knockdown of CKS1B significantly inhibited cell viability and invasion of PTC cells and suppressed STAT3/PD‐L1 signaling and Akt phosphorylation, while overexpression of CKS1B led to opposite results. Inhibition of STAT3 or PD‐L1 reversed the effects of overexpressed CKS1B on PTC cells.

Conclusion

The overexpression of CSK1B could promote cell viability and invasion of PTC cells through activation of STAT3/PD‐L1 signaling and Akt phosphorylation.

Downregulation of CKS1B restrains the proliferation, migration, invasion and angiogenesis of retinoblastoma cells through the MEK/ERK signaling pathway

Retinoblastoma (RB) is a common neoplasm that is exhibited in individuals globally. Increasing evidence demonstrated that cyclin‑dependent kinase regulatory subunit 1B (CKS1B) may be involved in the pathogenesis of various tumor types, including multiple myeloma and breast cancer. In the present study, the hypothesis that CKS1B downregulation would effectively inhibit the proliferation, invasion and angiogenesis of RB cells through the mitogen‑activated protein kinase kinase (MEK)/extracellular signal‑regulated kinase (ERK) signaling pathway was examined. Initial investigation of the expression profile of CKS1B in RB and adjacent retina tissues was performed using reverse transcription‑quantitative polymerase chain reaction and western blot analysis. A total of three RB cell lines, SO‑RB50, Y79 and HXO‑RB44, were examined for selection of the cell line with the highest expression of CKS1B, and human normal retinal vascular endothelial cells (ACBRI‑181) were also evaluated. CKS1B short hairpin RNA (shRNA) sequences (shRNA CKS1B‑1, shRNA CKS1B‑2 and shRNA CKS1B‑3) and negative control shRNA sequences were constructed and transfected into cells at the third generation to evaluate the role of shCKS1B and the MEK/ERK signaling pathway in RB. Furthermore, the effect of shCKS1B on cell proliferation, migration, invasion, apoptosis and angiogenesis was investigated. CKS1B was determined to be highly expressed in RB tissue, compared with adjacent retina tissue. SO‑RB50 and HXO‑RB44 cells treated with shRNA CKS1B‑1 and shRNA CKS1B‑2 were selected for the present experiments. Activation of the MEK/ERK signaling pathway increases the expression of MEK, ERK, B‑cell lymphoma 2, proliferating cell nuclear antigen, cyclin D1, vascular endothelia growth factor and basic fibroblast growth factor, enhances cell proliferation, migration, invasion and lumen formation, and decreases apoptosis. Following silencing CKS1B, the aforementioned conditions were reversed. The key observations of the present study demonstrated that shCKS1B can inhibit the proliferation, invasion and angiogenesis of RB cells by suppressing the MEK/ERK signaling pathway. Thus, CKS1B represents a potential research target in the development of therapeutics for RB.

Clinicopathologic implications of the miR-197/PD-L1 axis in oral squamous cell carcinoma

Immune escape of a tumor from tumor-infiltrating lymphocytes (TILs) is induced by PD-L1, which is suppressed by miR-197. We investigated the clinicopathologic implications of the miR-197/PD-L1 axis and its effects on TILs and the clinicopathologic features of oral squamous cell carcinoma (OSCC). We used RT-PCR and immunohistochemistry in 68 OSCC patients to analyze the correlations between tumoral expression of miR-197 and PD-L1 and the degree of tumoral invasion by TILs (CD3+, CD4+, CD8+, PD-1+, FoxP3+, and CD20+ lymphocytes). PD-L1 levels correlated inversely with miR-197 but correlated positively with TILs. The aggressive features of OSCC, including high stage, angiolymphatic invasion, perineural invasion, and death, were associated with TIL depletion. High T stage (T4) tumors also had low PD-L1 but had high miR-197 expression. In a univariate survival analysis of the full cohort, high miR-197 was associated with poor overall survival, whereas high PD-L1 expression (2+) associated with good overall survival. In a multivariate analysis stratified based on miR-197 (median), high PD-L1 expression (2+) was an independent favorable prognostic factor for overall survival (P = 0.040) in the miR-197^high subgroup but not the miR-197^low subgroup. These findings may have clinicopathologic implications for the miR-197/PD-L1 axis and TILs in OSCC.

Increased expression of Cks1 protein is associated with lymph node metastasis and poor prognosis in nasopharyngeal carcinoma

Background

The Cks1 protein is an essential factor in regulating cell cycle by mediating the ubiquitination of CDK inhibitor p27^kip1. It has been reported that aberrant expression of Cks1 and p27^kip1 proteins was found in various tumors and related to initiation and progression of carcinomas. However, the potential roles which Cks1 and p27^KIP1 proteins play in NPC remain unclear. This study aims to examine the expression status of Cks1 and p27^kip1 and their possible prognostic significance in NPC.

Methods

Paraffin-embedded specimens with NPC (n = 168) and non-tumor nasopharyngeal tissues (n = 49) were analyzed by IHC.

Results

Expression of Cks1 increased in NPC tissues compared with non-tumor nasopharyngeal tissues (P < 0.05), whereas p27^kip1 protein frequently expressed in non-tumor nasopharyngeal tissues compared with NPC tissues (P < 0.05). There was a significant reverse correlation between Cks1 and p27^kip1 protein expression in NPC (r = −0.189, P < 0.05).In addition, Kaplan-Meier survival curve showed that there was a significant tendency of shorter overall survival (OS) in NPC patients with Cks1 positive expression compared to negative ones, especially in patients with lymph node metastasis (P < 0.001, respectively). But there was no significance between p27^kip1 expression and survival viability of NPC patients. Multivariate Cox regression analysis further identified increased expression of Cks1 was the independent poor prognostic factor for NPC (p = 0.13).

Conclusion

Our research found expression of Cks1 increased and was inverse to the expression of p27^KIP1. High expression of Cks1 was significantly associated with lymph node metastasis and survival status in NPC. In addition, the abnormally high level of Cks1 protein was proved to be an independent poor prognostic factor in NPC. These results may provide novel clue for NPC therapy method.

Electronic supplementary material

The online version of this article (doi:10.1186/s13000-016-0589-9) contains supplementary material, which is available to authorized users.

Regulation of Transient Site-specific Copy Gain by MicroRNA

Intra-tumor copy number heterogeneity is commonly observed in cancer; however, the molecular mechanisms that contribute to heterogeneity remain poorly understood. Up-regulation of the histone demethylase KDM4A promotes transient site-specific copy gain (TSSG) in cells; therefore, uncovering how KDM4A levels are controlled is important for understanding the regulation of copy number heterogeneity. Here, we demonstrate that KDM4A is regulated by hsa-mir-23a-3p, hsa-mir-23b-3p, and hsa-mir-137. Altering expression of these microRNAs (miRNAs) regulates KDM4A-dependent TSSG. miRNA inhibition promoted copy gains and increased expression of the drug-resistant oncogene CKS1B, which was further substantiated in primary breast tumors. Consistent with increased CKS1B expression, miRNA inhibition reduced breast cancer cell sensitivity to cisplatin. Our data identify these miRNAs as regulators of TSSG and copy gains of a drug resistance gene.

Different Facets of Copy Number Changes: Permanent, Transient, and Adaptive

Chromosomal copy number changes are frequently associated with harmful consequences and are thought of as an underlying mechanism for the development of diseases. However, changes in copy number are observed during development and occur during normal biological processes. In this review, we highlight the causes and consequences of copy number changes in normal physiologic processes as well as cover their associations with cancer and acquired drug resistance. We discuss the permanent and transient nature of copy number gains and relate these observations to a new mechanism driving transient site-specific copy gains (TSSGs). Finally, we discuss implications of TSSGs in generating intratumoral heterogeneity and tumor evolution and how TSSGs can influence the therapeutic response in cancer.

p27Kip1 expression as a prognostic marker for squamous cell carcinoma of the head and neck

Regulation of the cell cycle is essential for carcinogenesis. The cell cycle is controlled by cyclin-dependent kinases (CDKs), which are upregulated by cyclins and downregulated by CDK inhibitors (CDKIs). Decreased p27^Kip1 expression has been associated with survival rate, tumor size, histological differentiation and the presence of lymph node metastasis in patients with various types of cancer. The aim of the current study is to provide a literature review on the association between p27^Kip1 expression and the clinical and pathological aspects of head and neck squamous cell carcinoma (HNSCC), and the expression of other CDKIs of the Cip/Kip family and cyclins. Throughout the literature, different methodologies were used to determine the immunohistochemical expression of p27^Kip1; thus, results concerning p27^Kip1 expression in HNSCC vary widely. However, it has now been confirmed that p27^Kip1 is underexpressed in SCC cells. p27 may be a promising marker for determining the prognosis of HNSCC, despite the marked variability of the results obtained. An association between p27 expression and survival rate, time to recurrence and tumor stage has been observed. Based on the information currently available, it is premature to recommend the analysis of p27^Kip1 expression in guiding HNSCC treatment planning. However, although relatively unstudied, the correlation between p27^Kip1 expression and other tumor suppressor genes may turn out to be important in determining the prognosis of HNSCC. Further prospective studies utilizing standardized laboratory methodologies and statistics that facilitate meta-analyses are required to confirm this proposal.

Hypoxia drives transient site-specific copy gain and drug-resistant gene expression. Genes Dev. 2015;29:1018-1031. [PMID: 25995187 PMCID: PMC4441050 DOI: 10.1101/gad.259796.115]

Black et al. demonstrate that hypoxia induces transient, site-specific copy gains in primary, nontransformed, and transformed human cells. Hypoxia-driven copy gains are dependent on the KDM4A histone demethylase and are blocked by inhibition of KDM4A with a small molecule or the natural metabolite succinate.

Copy number heterogeneity is a prominent feature within tumors. The molecular basis for this heterogeneity remains poorly characterized. Here, we demonstrate that hypoxia induces transient site-specific copy gains (TSSGs) in primary, nontransformed, and transformed human cells. Hypoxia-driven copy gains are not dependent on HIF1α or HIF2α; however, they are dependent on the KDM4A histone demethylase and are blocked by inhibition of KDM4A with a small molecule or the natural metabolite succinate. Furthermore, this response is conserved at a syntenic region in zebrafish cells. Regions with site-specific copy gain are also enriched for amplifications in hypoxic primary tumors. These tumors exhibited amplification and overexpression of the drug resistance gene CKS1B, which we recapitulated in hypoxic breast cancer cells. Our results demonstrate that hypoxia provides a biological stimulus to create transient site-specific copy alterations that could result in heterogeneity within tumors and cell populations. These findings have major implications in our understanding of copy number heterogeneity and the emergence of drug resistance genes in cancer.

Cks overexpression enhances chemotherapeutic efficacy by overriding DNA damage checkpoints

Cks1 and Cks2 are adaptor-like proteins that bind many cyclin-dependent kinases (Cdks). A wealth of clinical data has shown that Cks proteins are overexpressed in many types of human cancers and this often correlates with increased tumor aggressiveness. Previously, we showed that Cks overexpression abrogates the intra-S phase checkpoint, a major barrier to oncogene-mediated transformation. Interestingly, the intra-S phase checkpoint is crucial for the cellular response to replication stress, a major pathway of apoptosis induction by many chemotherapeutic agents. Here, we demonstrate cancer cells that overexpress Cks1 or Cks2 override the intra-S phase checkpoint in the presence of replication stress-inducing chemotherapies such as 5-Fluorourocil (5-FU) and methotrexate (MTX) leading to enhanced sensitivity in vitro and in vivo. Furthermore, enforced expression of Cks1 in a MTX-resistant breast cancer cell line was found to restore drug sensitivity. Our results suggest that Cks proteins are important determinants of apoptosis induction of replication stress-inducing chemotherapies such as 5-FU.

Genome wide analysis of chromosomal alterations in oral squamous cell carcinomas revealed over expression of MGAM and ADAM9

Despite the advances in diagnosis and treatment of oral squamous cell carcinoma (OSCC), mortality and morbidity rates have not improved over the past decade. A major drawback in diagnosis and treatment of OSCC is the lack of knowledge relating to how genetic instability in oral cancer genomes affects oral carcinogenesis. Hence, the key aim of this study was to identify copy number alterations (CNAs) that may be cancer associated in OSCC using high-resolution array comparative genomic hybridization (aCGH). To our knowledge this is the first study to use ultra-high density aCGH microarrays to profile a large number of OSCC genomes (n = 46). The most frequently amplified CNAs were located on chromosome 11q11(52%), 2p22.3(52%), 1q21.3-q22(54%), 6p21.32(59%), 20p13(61%), 7q34(52% and 72%),8p11.23-p11.22(80%), 8q11.1-q24.4(54%), 9q13-q34.3(54%), 11q23.3-q25(57%); 14q21.3-q31.1(54%); 14q31.3-q32.33(57%), 20p13-p12.3(54%) and 20q11.21-q13.33(52%). The most frequently deleted chromosome region was located on 3q26.1 (54%). In order to verify the CNAs from aCGH using quantitative polymerase chain reaction (qPCR), the three top most amplified regions and their associated genes, namely ADAM5P (8p11.23-p11.22), MGAM (7q34) and SIRPB1 (20p13.1), were selected in this study. The ADAM5P locus was found to be amplified in 39 samples and deleted in one; MGAM (24 amplifications and 3 deletions); and SIRPB1 (12 amplifications, others undetermined). On the basis of putative cancer-related annotations, two genes, namely ADAM metallopeptidase domain 9 (ADAM9) and maltase-glucoamylase alpha-glucosidase (MGAM), that mapped to CNA regions were selected for further evaluation of their mRNA expression using reverse transcriptase qPCR. The over-expression of MGAM was confirmed with a 6.6 fold increase in expression at the mRNA level whereas the fold change in ADAM9 demonstrated a 1.6 fold increase. This study has identified significant regions in the OSCC genome that were amplified and resulted in consequent over-expression of the MGAM and ADAM9 genes that may be utilized as biological markers for OSCC.

Cks1: Structure, Emerging Roles and Implications in Multiple Cancers

Deregulation of the cell cycle results in loss of normal control mechanisms that prevent aberrant cell proliferation and cancer progression. Regulation of the cell cycle is a highly complex process with many layers of control. One of these mechanisms involves timely degradation of CDK inhibitors (CKIs) like p27^Kip1 by the ubiquitin proteasomal system (UPS). Cks1 is a 9 kDa protein which is frequently overexpressed in different tumor subtypes, and has pleiotropic roles in cell cycle progression, many of which remain to be fully characterized. One well characterized molecular role of Cks1 is that of an essential adaptor that regulates p27^Kip1 abundance by facilitating its interaction with the SCF-Skp2 E3 ligase which appends ubiquitin to p27^Kip1 and targets it for degradation through the UPS. In addition, emerging research has uncovered p27^Kip1-independent roles of Cks1 which have provided crucial insights into how it may be involved in cancer progression. We review here the structural features of Cks1 and their functional implications, and also some recently identified Cks1 roles and their involvement in breast and other cancers.