Glycogen synthase kinase-3β mediated regulation of matrix metalloproteinase-9 and its involvement in oral squamous cell carcinoma progression and invasion

Crosstalk between PD-L1 and Jak2-Stat3/ MAPK-AP1 signaling promotes oral cancer progression, invasion and therapy resistance

BACKGROUND

Programmed cell death ligand-1 (PD-L1)is an antitumor immunity molecule and a great target to cure oral cancer; nonetheless, the limited success can be attributed to many complex pathways and tumor-related interferences.

METHODS

In the present study, 150 human oral squamous cell carcinoma (OSCC) tissue samples, including 17 adjacent normals, 56 primary tumors, 47 invasive tumors, and 30 therapy-resistant (RT) samples, were included. The parental/cisplatin-resistant (CisR-SCC4/9) cells were utilized for overexpression (Jak1-3 wild type and catalytically inactive), knockdown (PD-L1 siRNA), targeting MAPK/PI3K/Jak-Stat pathways (SMIs) and checking microsomes. The expression of PD-L1, transcription factors (TFs), signaling pathways, survival/apoptosis, therapy resistance, and invasiveness-related molecules/their activity were determined by RT-PCR, Immunohistochemistry, Western blot, Gelatin Zymography, and MTT assay.

RESULTS

Advanced OSCC tumors (invasive and drug-resistance), CisR-SCC4/9 cells, and secretory exosomes (CisR-SCC4/9) were found with increased PD-L1 expression. PD-L1 mRNA/protein showed a positive correlation with different TFs (AP1 > Stat3 > c-myc > NFκB) in tumor samples. The PD-L1 expression was more influenced by Jak-Stat/ MAPK-AP1 pathways over PI3K. The ectopic expression of Jak1-3 suggests Jak2 inducted PD-L1 level over Jak1/Jak3. Finally, PD-L1 directly supports survival (Bcl-xL, Bax, cleaved caspase-3), invasion (MMP2/9), and drug-resistance (ALDH-1A1/-3A1) program in OSCC through its link with several molecules.

CONCLUSIONS

PD-L1 was regulated mainly by the Jak2-Stat3/ MAPK-AP1 pathway, and besides the routine immunological functions, it supports OSCC survival, invasion, and therapy resistance. PD-L1 can be used as an indicator of severity and can be targeted along with Jak2-Stat3/ MAPK-AP1 for a better outcome OSCC.

Therapeutic targeting of microtubule affinity-regulating kinase 4 in cancer and neurodegenerative diseases

Microtubule affinity-regulating kinase 4 (MARK4) is a member of the Ser/Thr protein kinase family, phosphorylates the microtubule-connected proteins and plays a vital role in causing cancers and neurodegenerative diseases. This kinase modulates multiple signaling pathways, including mammalian target of rapamycin, nuclear factor-κB, and Hippo-signaling, presumably responsible for cancer and Alzheimer's. MARK4 acts as a negative controller of the Hippo-kinase cassette for promoting YAP/TAZ action, and the loss of MARK4 detains the tumorigenic properties of cancer cells. MARK4 is involved in tau hyperphosphorylation that consequently affects neurodegeneration. MARK4 is a promising drug target for cancer, diabetes, and Alzheimer's. Developing the potent and selective inhibitors of MAKR4 are promising in the therapeutic management of associated diseases. Despite its great significance, a few reviews are available to discuss its structure, function and clinical significance. In the current review, we aimed to provide detailed information on the structural features of MARK4 targeted in drug development and its role in various signaling pathways related to cancer and neurodegenerative diseases. We further described the therapeutic potential of MARK4 inhibitors in preventing numerous diseases. Finally, the updated information on MARK4 will be helpful in the further development of effective therapeutic molecules.

Therapeutic Targeting of Regulated Signaling Pathways of Non-Small Cell Lung Carcinoma

Non-small cell lung carcinoma (NSCLC) is the most common cancer globally. Phytochemicals and small molecule inhibitors significantly prevent varying types of cancers, including NSCLC. These therapeutic molecules serve as important sources for new drugs that interfere with cellular proliferation, apoptosis, metastasis, and angiogenesis by regulating signaling pathways. These molecules affect several cellular signaling cascades, including p53, NF-κB, STAT3, RAS, MAPK/ERK, Wnt, and AKT/PI3K, and are thus implicated in the therapeutic management of cancers. This review aims to describe the bioactive compounds and small-molecule inhibitors, their anticancer action, and targeting cellular signaling cascades in NSCLC. We highlighted the therapeutic potential of Epigallocatechin gallate (EGCG), Perifosine, ABT-737, Thymoquinine, Quercetin, Venetoclax, Gefitinib, and Genistein. These compounds are implicated in the therapeutic management of NSCLC. This review further offers deeper mechanistic insights into different signaling pathways that could be targeted for NSCLC therapy by phytochemicals and small-molecule inhibitors.

Role and regulation of GLUT1/3 during oral cancer progression and therapy resistance

OBJECTIVE

This study aimed to determine whether glucose transporter-1/3 (GLUT1/3) increased expression could contribute to oral tumor severity. Furthermore, this study detected whether GLUT1/3 mRNA/protein was associated with oncogenic transcription factors (HIF1α, AP1 and NFκB) and whether by blocking GLUT1 along with cisplatin could sensitize drug-resistant OSCC cells.

DESIGN

We used 120 post-operated human tissue samples, including 35 primary tumors (PT), 43 invasive tumors (N1-3), 17 recurrent chemoradiation-resistant tumors (RCRT), and 25 PT-adjacent normal tissues (AN). The cisplatin-resistant (CisR-SCC4/9) cells were generated using a drug escalation strategy from parental SCC4/9 cells. The BAY-876 treatment blocked GLUT1 in OSCC cells. Western Blot, Immunohistochemistry, and reverse transcription polymerase chain reaction (RT-PCR) were used to detect various proteins and mRNA. Cell survival was determined by MTT assay.

RESULTS

GLUT1/3 expression was observed more in PT over AN tissue (PT > AN), N1-3 > PT, and .RCRT > PT. GLUT1 expression was maximum in the RCRT group and CisR-SCC4/9 cells over their parental counterpart, linked with tumor size (p=0.0037) and loco-regional invasiveness (p=0.0422). GLUT1/3 mRNA/protein was correlated (positively) with oncogenic transcription factors (TFs) like HIF1α, AP1 and NFκB. We found the degree of positive correlation of these TFs with GLUT1/3 was in the order c-Jun > HIF1α > Fra-2 > NFκB > c-Fos. Treatment of BAY-876 and cisplatin-induced cell death in both CisR-SCC4/9 cells, possibly by triggering apoptosis and autophagy.

CONCLUSION

Collectively, our results demonstrated increased GLUT1/3 overexpression linked with oral tumor severity like invasion and therapy resistance, and it was powered mainly by c-Jun (AP1). Blocking GLUT1 receptors and cisplatin application can sensitize CisR-OSCC cells.

Biochemical features and therapeutic potential of α-Mangostin: Mechanism of action, medicinal values, and health benefits

α-Mangostin (α-MG) is a natural xanthone obtained from the pericarps of mangosteen. It exhibits excellent potential, including anti-cancer, neuroprotective, antimicrobial, antioxidant, and anti-inflammatory properties, and induces apoptosis. α-MG controls cell proliferation by modulating signaling molecules, thus implicated in cancer therapy. It possesses incredible pharmacological features and modulates crucial cellular and molecular factors. Due to its lesser water solubility and pitiable target selectivity, α-MG has limited clinical application. As a known antioxidant, α-MG has gained significant attention from the scientific community, increasing interest in extensive technical and biomedical applications. Nanoparticle-based drug delivery systems were designed to improve the pharmacological features and efficiency of α-MG. This review is focused on recent developments on the therapeutic potential of α-MG in managing cancer and neurological diseases, with a special focus on its mechanism of action. In addition, we highlighted biochemical and pharmacological features, metabolism, functions, anti-inflammatory, antioxidant effects and pre-clinical applications of α-MG.

Investigating regulated signaling pathways in therapeutic targeting of non-small cell lung carcinoma

Non-small cell lung carcinoma (NSCLC) is the most common malignancy worldwide. The signaling cascades are stimulated via genetic modifications in upstream signaling molecules, which affect apoptotic, proliferative, and differentiation pathways. Dysregulation of these signaling cascades causes cancer-initiating cell proliferation, cancer development, and drug resistance. Numerous efforts in the treatment of NSCLC have been undertaken in the past few decades, enhancing our understanding of the mechanisms of cancer development and moving forward to develop effective therapeutic approaches. Modifications of transcription factors and connected pathways are utilized to develop new treatment options for NSCLC. Developing designed inhibitors targeting specific cellular signaling pathways in tumor progression has been recommended for the therapeutic management of NSCLC. This comprehensive review provided deeper mechanistic insights into the molecular mechanism of action of various signaling molecules and their targeting in the clinical management of NSCLC.

Screening and identification of miR-181a-5p in oral squamous cell carcinoma and functional verification in vivo and in vitro

BACKGROUND

Oral squamous cell carcinoma (OSCC) is a common malignant tumor associated with poor prognosis. MicroRNAs (miRNAs) play crucial regulatory roles in the cancer development. However, the role of miRNAs in OSCC development and progression is not well understood.

METHODS

We sought to establish a dynamic Chinese hamster OSCC animal model, construct miRNA differential expression profiles of its occurrence and development, predict its targets, and perform functional analysis and validation in vitro.

RESULTS

Using expression and functional analyses, the key candidate miRNA (miR-181a-5p) was selected for further functional research, and the expression of miR-181a-5p in OSCC tissues and cell lines was detected. Subsequently, transfection technology and a nude mouse tumorigenic model were used to explore potential molecular mechanisms. miR-181a-5p was significantly downregulated in human OSCC specimens and cell lines, and decreased miR-181a-5p expression was observed in multiple stages of the Chinese hamster OSCC animal model. Moreover, upregulated miR-181a-5p significantly inhibited OSCC cell proliferation, colony formation, invasion, and migration; blocked the cell cycle; and promoted apoptosis. BCL2 was identified as a target of miR-181a-5p. BCL2 may interact with apoptosis- (BAX), invasion- and migration- (TIMP1, MMP2, and MMP9), and cell cycle-related genes (KI67, E2F1, CYCLIND1, and CDK6) to further regulate biological behavior. Tumor xenograft analysis indicated that tumor growth was significantly inhibited in the high miR-181a-5p expression group.

CONCLUSION

Our findings indicate that miR-181a-5p can be used as a potential biomarker and provide a novel animal model for mechanistic research on oral cancer.

Polymorphisms and haplotypes of TLR-4/9 associated with bacterial infection, gingival inflammation/recession and oral cancer

BACKGROUND

The expression and SNPs of innate immunity genes TLR-4/9 for bacterial infection, gingival inflammation/gingival recession (GIGR), and oral squamous cell carcinoma (OSCC) are largely unknown.

PATIENTS AND METHOD

235 specimens (120 OSCC cases, among which 85 cases with either Porphyromonas gingivalis, Fusobacterium nucleatum or Treponema denticola infection and GIGR) and 115 healthy controls were used to know the expression and polymorphisms (TLR-4: N1:rs10759931, N2:rs11536889, N3:rs1927911, N4:rs4986790; TLR-9: N5:rs5743836, N6:rs352140, N7:rs187084 and N8:rs352139) of TLR-4/9 by western blot, RT-PCR, and allele-specific (AS)-PCR followed by sequencing.

RESULTS

Increased TLR-4/9 mRNA/protein expression, bacterial infection (BI) and GIGR were associated with OSCC incidence. One of the three BI and GIGR was observed in 70.83% of OSCC cases, whereas all the HC used were free from any of these three BI/GIGR. The N3: CT-genotype (Odds Ratio hereafter as O.R.=1.811, p = 0.0338), TT-genotype (O.R.=3.094, p = 0.0124), 'T'-allele (O.R.=1.821, p = 0.003), N4: AG-genotype (O.R.=2.015, p = 0.0222) and 'G'-allele (O.R.=1.86, p = 0.018) of TLR-4 as well as the N5: CC-genotype (O.R.=3.939, p = 0.0017), 'C'-allele (O.R.=1.839, p = 0.0042), N6: AA-genotype (O.R.=2.195, p = 0.0234), 'A'-allele (O.R.=1.569, p = 0.0163), N7: TC-genotype (O.R.=2.083, p = 0.0136), CC-genotype (O.R.=2.984, p = 0.003) and 'C'-allele (O.R.=1.885, p = 0.0008) of TLR-9 were associated with increased OSCC risk. Similarly, the N2:'C'-allele (O.R.=1.615, p = 0.0382), N3: TT-genotype (O.R.=2.829, p = 0.0336), 'T'-allele (O.R.=1.742, p = 0.0115), N4: AG-genotype (O.R.=2.221, p = 0.0147) and 'G'-allele (O.R.=1.890, p = 0.0238) of TLR-4 as well as the N5: CC-genotype (O.R.=2.830, p = 0.031), N6: AA-genotype (O.R.=2.6, p = 0.0122) and 'A'-allele (O.R.=1.746, p = 0.0064), N7:CC-genotype (O.R.2.706, p = 0.0111) and 'C'-allele (O.R. 1.774, p = 0.0055) of TLR-9 were correlated with GIGR and BI. TLR-4 (N1-N2-N3-N4: A-C-T-A (O.R.=2.1, p = 0.0069) and TLR-9 (N5-N6-N7-N8: T-A-C-A (O.R.=2.019, p = 0.0263); C-A-C-A (O.R.=6.0, p = 0.0084); C-A-C-G (O.R.=4.957, p = 0.0452) haplotypes were linked with OSCC vulnerability, while the TLR-4 (N1-N2-N3-N4: G-C-C-A (O.R.=0.5752, p = 0.0131) and TLR-9 (N5-N6-N7-N8: T-G-T-A (O.R.=0.5438, p = 0.0314); T-G-T-G (O.R.=0.5241, p = 0.036) haplotypes offered protection.

CONCLUSION

TLR-4/9 expression, polymorphisms, and BI-induced GIGR could increase OSCC risk. This may be used in pathogenesis and oral cancer prediction.

Therapeutic implications and clinical manifestations of thymoquinone

Thymoquinone (TQ), a natural phytochemical predominantly found in Nigella sativa, has been investigated for its numerous health benefits. TQ showed anti-cancer, anti-oxidant, and anti-inflammatory properties, validated in various disease models. The anti-cancer potential of TQ is goverened by anti-proliferation, cell cycle arrest, apoptosis induction, ROS production, anti-metastasis and anti-angiogenesis, inhibition of cell migration and invasion action. Additionally, TQ exhibited antitumor activity via the modulation of multiple pathways and molecular targets, including Akt, ERK1/2, STAT3, and NF-κB. The present review highlighted the anticancer potential of TQ . We summarize the anti-cancer, anti-oxidant, and anti-inflammatory properties of TQ, focusing on its molecular targets and its promising action in cancer therapy. We further described the molecular mechanisms by which TQ prevents signaling pathways that mediate cancer progression, invasion, and metastasis.

Structure-guided design and development of cyclin-dependent kinase 4/6 inhibitors: A review on therapeutic implications

Cyclin-dependent kinase 6 (EC 2.7.11.22) play significant roles in numerous biological processes and triggers cell cycle events. CDK6 controlled the transcriptional regulation. A dysregulated function of CDK6 is linked with the development of progression of multiple tumor types. Thus, it is considered as an effective drug target for cancer therapy. Based on the direct roles of CDK4/6 in tumor development, numerous inhibitors developed as promising anti-cancer agents. CDK4/6 inhibitors regulate the G1 to S transition by preventing Rb phosphorylation and E2F liberation, showing potent anti-cancer activity in several tumors, including HR+/HER2- breast cancer. CDK4/6 inhibitors such as abemaciclib, palbociclib, and ribociclib, control cell cycle, provoke cell senescence, and induces tumor cell disturbance in pre-clinical studies. Here, we discuss the roles of CDK6 in cancer along with the present status of CDK4/6 inhibitors in cancer therapy. We further discussed, how structural features of CDK4/6 could be implicated in the design and development of potential anti-cancer agents. In addition, the therapeutic potential and limitations of available CDK4/6 inhibitors are described in detail. Recent pre-clinical and clinical information for CDK4/6 inhibitors are highlighted. In addition, combination of CDK4/6 inhibitors with other drugs for the therapeutic management of cancer are discussed.

Therapeutic targeting of TANK-binding kinase signaling towards anticancer drug development: Challenges and opportunities

TANK-binding kinase 1 (TBK1) plays a fundamental role in regulating the cellular responses and controlling several signaling cascades. It regulates inflammatory, interferon, NF-κB, autophagy, and Akt pathways. Post-translational modifications (PTM) of TBK1 control its action and subsequent cellular signaling. The dysregulation of the TBK1 pathway is correlated to many pathophysiological conditions, including cancer, that implicates the promising therapeutic advantage for targeting TBK1. The present study summarizes current updates on the molecular mechanisms and cancer-inducing roles of TBK1. Designed inhibitors of TBK1 are considered a potential therapeutic agent for several diseases, including cancer. Data from pre-clinical tumor models recommend that the targeting of TBK1 could be an attractive strategy for anti-tumor therapy. This review further highlighted the therapeutic potential of potent and selective TBK1 inhibitors, including Amlexanox, Compound II, BX795, MRT67307, SR8185 AZ13102909, CYT387, GSK8612, BAY985, and Domainex. These inhibitors may be implicated to facilitate therapeutic management of cancer and TBK1-associated diseases in the future.

Bax/Bcl-2 Cascade Is Regulated by the EGFR Pathway: Therapeutic Targeting of Non-Small Cell Lung Cancer

Non-small cell lung carcinoma (NSCLC) comprises 80%-85% of lung cancer cases. EGFR is involved in several cancer developments, including NSCLC. The EGFR pathway regulates the Bax/Bcl-2 cascade in NSCLC. Increasing understanding of the molecular mechanisms of fundamental tumor progression has guided the development of numerous antitumor drugs. The development and improvement of rationally planned inhibitors and agents targeting particular cellular and biological pathways in cancer have been signified as a most important paradigm shift in the strategy to treat and manage lung cancer. Newer approaches and novel chemotherapeutic agents are required to accompany present cancer therapies for improving efficiency. Using natural products as a drug with an effective delivery system may benefit therapeutics. Naturally originated compounds such as phytochemicals provide crucial sources for novel agents/drugs and resources for tumor therapy. Applying the small-molecule inhibitors (SMIs)/phytochemicals has led to potent preclinical discoveries in various human tumor preclinical models, including lung cancer. In this review, we summarize recent information on the molecular mechanisms of the Bax/Bcl-2 cascade and EGFR pathway in NSCLC and target them for therapeutic implications. We further described the therapeutic potential of Bax/Bcl-2/EGFR SMIs, mainly those with more potent and selectivity, including gefitinib, EGCG, ABT-737, thymoquinone, quercetin, and venetoclax. In addition, we explained the targeting EGFR pathway and ongoing in vitro and in vivo and clinical investigations in NSCLC. Exploration of such inhibitors facilitates the future treatment and management of NSCLC.

Therapeutic Implications of Caffeic Acid in Cancer and Neurological Diseases

Caffeic acid (CA) is found abundantly in fruits, vegetables, tea, coffee, oils, and more. CA and its derivatives have been used for many centuries due to their natural healing and medicinal properties. CA possesses various biological and pharmacological activities, including antioxidant, anti-inflammatory, anticancer, and neuroprotective effects. The potential therapeutic effects of CA are mediated via repression and inhibition of transcription and growth factors. CA possesses potential anticancer and neuroprotective effects in human cell cultures and animal models. However, the biomolecular interactions and pathways of CA have been described highlighting the target binding proteins and signaling molecules. The current review focuses on CA’s chemical, physical, and pharmacological properties, including antioxidant, anti-inflammatory, anticancer, and neuroprotective effects. We further described CA’s characteristics and therapeutic potential and its future directions.

Potential Therapeutic Implications of Caffeic Acid in Cancer Signaling: Past, Present, and Future

Caffeic acid (CA) has been present in many herbs, vegetables, and fruits. CA is a bioactive compound and exhibits various health advantages that are linked with its anti-oxidant functions and implicated in the therapy and prevention of disease progression of inflammatory diseases and cancer. The anti-tumor action of CA is attributed to its pro-oxidant and anti-oxidant properties. CA’s mechanism of action involves preventing reactive oxygen species formation, diminishing the angiogenesis of cancer cells, enhancing the tumor cells’ DNA oxidation, and repressing MMP-2 and MMP-9. CA and its derivatives have been reported to exhibit anti-carcinogenic properties against many cancer types. CA has indicated low intestinal absorption, low oral bioavailability in rats, and pitiable permeability across Caco-2 cells. In the present review, we have illustrated CA’s therapeutic potential, pharmacokinetics, and characteristics. The pharmacological effects of CA, the emphasis on in vitro and in vivo studies, and the existing challenges and prospects of CA for cancer treatment and prevention are discussed in this review.

Potential Therapeutic Implications of Caffeic Acid in Cancer Signaling: Past, Present, and Future

Caffeic acid (CA) has been present in many herbs, vegetables, and fruits. CA is a bioactive compound and exhibits various health advantages that are linked with its anti-oxidant functions and implicated in the therapy and prevention of disease progression of inflammatory diseases and cancer. The anti-tumor action of CA is attributed to its pro-oxidant and anti-oxidant properties. CA’s mechanism of action involves preventing reactive oxygen species formation, diminishing the angiogenesis of cancer cells, enhancing the tumor cells’ DNA oxidation, and repressing MMP-2 and MMP-9. CA and its derivatives have been reported to exhibit anti-carcinogenic properties against many cancer types. CA has indicated low intestinal absorption, low oral bioavailability in rats, and pitiable permeability across Caco-2 cells. In the present review, we have illustrated CA’s therapeutic potential, pharmacokinetics, and characteristics. The pharmacological effects of CA, the emphasis onin vitro and in vivostudies, and the existing challenges and prospects of CA for cancer treatment and prevention are discussed in this review.

Epigallocatechin 3-gallate: From green tea to cancer therapeutics

Epigallocatechin 3-gallate (EGCG) possesses various biological functions, including anti-cancer and anti-inflammatory properties. EGCG is an abundant polyphenolic component originating from green tea extract that has exhibited versatile bioactivities in combating several cancers. This review highlights the pharmacological features of EGCG and its therapeutic implications in cancer and other metabolic diseases. It modulates numerous signaling pathways, regulating cells' undesired survival and proliferation, thus imparting strong tumor chemopreventive and therapeutic effects. EGCG initiates cell death through the intrinsic pathway and causes inhibition of EGFR, STAT3, and ERK pathways in several cancers. EGCG alters and inhibits ERK1/2, NF-κB, and Akt-mediated signaling, altering the Bcl-2 family proteins ratio and activating caspases in tumor cells. This review focuses on anti-cancer, anti-oxidant, anti-inflammatory, anti-angiogenesis, and apoptotic effects of EGCG. We further highlighted the potential of EGCG in different types of cancer, emphasizing clinical trials formulations that further improve our understanding of the therapeutic management of cancer and inflammatory diseases.

ERK-mediated upregulation of matrix metalloproteinase-2 promotes the invasiveness in human oral squamous cell carcinoma (OSCC)

BACKGROUND

Loco-regional invasion is commonly found in oral squamous cell carcinoma (OSCC) and is associated with its poor survival rate. Matrix metalloproteinase-2 (MMP-2) has been implicated in OSCC progression, but its regulation is poorly understood.

MATERIALS AND METHODS

Here, one hundred twenty-seven different post-operated human oral cancer tissue samples were analyzed. The messenger RNA (mRNA) expression, protein expression, and MMP-2 activity and MT1-MMP, TIMP-2, and TFs (NFκB, AP1, Sp1, and Twist) were observed semi-quantitative RT-PCR, western blotting, and gelatin zymography. In addition, OSCC derived Cal-27, SCC4/9 cells, photochemical ECGC, and MAPK-pathway inhibitor PD98059 were utilized for in vitro testing and wound healing assay.

RESULT

s: Increased protein and activity level of MMP-2 was detected in non-invasive (N₀) and invasive (N_1-3) oral tumors as compared to the control (adjacent normal) samples. MMP-2 protein and mRNA expression were positively associated with the TFs and MT1-MMP, negatively associated with TIMP-2 expression. Similarly, the MMP-2 expression/activity was related to several signal-transduction pathways like ERK1/2 and wnt-β-catenin pathways. Treatment of ECGC/MEK inhibitor (PD98059) diminished MMP-2 activity and invasion/migration potential in OSCC.

CONCLUSION

Our research suggests that the ERK1/2 driven overexpression/activation of MMP-2 was linked with the overall OSCC invasion and metastasis. Treatment of MEK inhibitor (PD98059) and ECGC diminished MMP-2 activity and thus could be exploited as a therapeutic strategy to control the invasive OSCC.

Infection by High-Risk Human Papillomaviruses, Epithelial-to-Mesenchymal Transition and Squamous Pre-Malignant or Malignant Lesions of the Uterine Cervix: A Series of Chained Events?

Wound healing requires static epithelial cells to gradually assume a mobile phenotype through a multi-step process termed epithelial-to-mesenchymal transition (EMT). Although it is inherently transient and reversible, EMT perdures and is abnormally activated when the epithelium is chronically exposed to pathogens: this event deeply alters the tissue and eventually contributes to the development of diseases. Among the many of them is uterine cervical squamous cell carcinoma (SCC), the most frequent malignancy of the female genital system. SCC, whose onset is associated with the persistent infection of the uterine cervix by high-risk human papillomaviruses (HR-HPVs), often relapses and/or metastasizes, being resistant to conventional chemo- or radiotherapy. Given that these fearsome clinical features may stem, at least in part, from the exacerbated and long-lasting EMT occurring in the HPV-infected cervix; here we have reviewed published studies concerning the impact that HPV oncoproteins, cellular tumor suppressors, regulators of gene expression, inflammatory cytokines or growth factors, and the interactions among these effectors have on EMT induction and cervical carcinogenesis. It is predictable and desirable that a broader comprehension of the role that EMT inducers play in SCC pathogenesis will provide indications to flourish new strategies directed against this aggressive tumor.

Glycogen synthase kinase-3β inactivation promotes cervical cancer progression, invasion, and drug resistance

Human papillomavirus (HPV) infection-dependent cervical cancer is one of the most common gynecological cancers and often becomes aggressive, with rapid proliferation, invasion/migration, and drug resistance. Here, 135 fresh human cervical squamous cell carcinoma (CSCC) tissue specimens, comprising 21 adjacent normal (AN), 30 cervical intraepithelial neoplasia (CIN_1-3 ), 45 CSCC, and 39 drugs (chemo-radiation)-resistant cervical tumor (DRCT) tissues were included. HPV-positive (HeLa, SiHa), HPV-negative (C33A), and cisplatin-resistant (CisR-HeLa/-SiHa/-C33A) cell lines were used for in vitro studies. HPV16/18 oncoproteins E6/E7, pERK1/2, and glycogen synthase kinase-3 (GSK3) and the matrix metalloproteinases (MMPs) MMP-9/-2 were assessed using immunohistochemistry, WB, and gelatin zymography. HPV16/18 infection was observed in 16.7% of the CIN_1-3 , 77.8% of the CSCC, and 89.7% of DRCT samples. Total and inactive GSK3β expressions were associated with overall CSCC progression (p = 0.039 and p = 0.024, respectively) and chemoresistance (p = 0.004 and p = 0.014, respectively). Positive correlations were observed, between the expression of E6 and pGSK3β expression (p = 0.013); E6 and CSCC progression (p < 0.0001)/drug resistance (p = 0.0001). CisR-HeLa/-SiHa was more dependent on pGSK3β, and activation of GSK3 by SMIs (iAkt), treatment with nimbolide, or knockdown of E6/E7 reduced cisplatin resistance and promoted apoptosis. Hence, the activation of GSK3β with nimbolide and iAkt can be exploited for therapeutic interventions of cervical cancer.

GSK-3 Inhibition Modulates Metalloproteases in a Model of Lung Inflammation and Fibrosis

Idiopathic pulmonary fibrosis (IPF) is mainly characterized by aberrant extracellular matrix deposition, consequent to epithelial lung injury and myofibroblast activation, and inflammatory response. Glycogen synthase kinase 3 (GSK-3) is a serine-threonine kinase involved in several pathways, and its inhibition has been already suggested as a therapeutic strategy for IPF patients. There is evidence that GSK-3 is able to induce matrix metalloproteinase (MMP) expression and that its inhibition modulates MMP expression in the tissues. The aim of our study was to investigate the role of GSK-3 and its inhibition in the modulation of MMP-9 and -2 in an in vivo mouse model of lung fibrosis and in vitro using different cell lines exposed to pro-inflammatory or pro-fibrotic stimuli. We found that GSK-3 inhibition down-modulates gene expression and protein levels of MMP-9, MMP-2, and their inhibitors TIMP-1 and TIMP-2 in inflammatory cells harvested from bronchoalveolar lavage fluid (BALF) of mice treated with bleomycin as well as in interstitial alveolar macrophages and cuboidalized epithelial alveolar cells. To the same extent, GSK-3 inhibition blunted the increased MMP-9 and MMP-2 activity induced by pro-fibrotic stimuli in a human lung fibroblast cell line. Moreover, the αSMA protein level, a marker of fibroblast-to-myofibroblast transition involved in fibrosis, was decreased in primary fibroblasts treated with TGFβ following GSK-3 inhibition. Our results confirm the implication of GSK-3 in lung inflammation and fibrosis, suggesting that it might play its role by modulating MMP expression and activity but also pushing fibroblasts toward a myofibroblast phenotype and therefore enhancing extracellular matrix deposition. Thus, its inhibition could represent a possible therapeutic strategy.

Bcl-xL expression and regulation in the progression, recurrence, and cisplatin resistance of oral cancer

BACKGROUND

Bcl-xL is an anti-apoptotic molecule, but its role in the progression and recurrent/ drug-resistant oral squamous cell carcinoma (OSCC) is poorly understood.

MATERIALS AND METHODS

A total of one hundred twenty-five human OSCC tissue specimens including twenty-nine adjacent normals (AN), sixty-nine primary tumors (PT), twenty-seven recurrent chemoradiation resistance (RCRT) samples, and oral tongue SCC derived cisplatin-resistant (CisR SCC-4/-9) cells were used, for this study. Protein/mRNA expression levels of Bcl-xL and its regulation by ERK1/2, Stat-3, p53, NFκB, AP-1 (components: c-Jun, c-Fos, and Fra-2) molecules, and cell viability were measured by immunohistochemistry, Western blot, RT-PCR, and MTT analysis. Further, the individual and synergistic effects of Fra-2 (siRNA) and nimbolide were tested in CisR SCC-4/-9 cells.

RESULTS

Progressive increase of Bcl-xL expression and its transcriptional-deregulation was observed with OSCC progression and resistance. Among all the possible upstream regulators of Bcl-xL, such as ERK1/2, Stat-3, p53, AP-1, and NFκB, the TF AP-1 (r = 0.644, p = 0.0001) showed maximum association with Bcl-xL mRNA expression. Though differential expression of AP-1 components were detected in OSCC specimens, with more striking positive-correction of c-Jun (r = 0.381, p = 0.049), c-Fos (r = 0.139, p = 0.488, ns) and Fra-2 (r = 0.664, p = 0.0001) with Bcl-xL expression observed stronger in RCRT tumor subgroup. Further, knockdown of Fra-2 and the application of plant-based phytochemical nimbolide decreased Bcl-xL expression and induced apoptosis in CisR SCC-4/-9 cells.

CONCLUSION

Collectively, we have demonstrated the role of Bcl-xL and AP-1 (Fra-2), causing OSCC progression and cisplatin resistance. Targeting Bcl-xL upstream pathway along with the application of nimbolide might be beneficial in eliminating drug-resistant OSCC.

Circular RNA Circ_0008450 Regulates the Invasion, Migration, and Proliferation of Oral Squamous Carcinoma Human Oral Squamous Cell 3 Cells by Targeting miR-1294

To determine the role of the circ_0008450/miR-1294 molecular axis in the proliferation, migration, and invasion of oral squamous cell carcinoma (OSCC) cells, the expression levels of circ_0008450 and miR-1294 in OSCC and neighboring non-cancerous tissues were detected by real-time quantitative polymerase chain reaction. Human OSCC HSC3 cells were transfected with negative control (NC) small interfering (Si) RNA (Si-NC), Si-circ_0008450, micro RNA (miR)-NC, miR-1294 mimics, anti-miR-1294, anti-Si-circ_0008450, or anti-miR-NC. The activity of HSC3 cells was detected with the CCK-8 assay. The transwell assay was used to assess the invasion and migration of HSC3 cells. The targeted relationship between miR-1294 and CIRc_0008450 was detected with the dualluciferase report assay. Western blot analysis was performed to measure the protein expression levels of matrix metalloproteinase (MMP)-2, MMP-9, and Ki-67 (also known as MKI67). As compared to neighboring non-cancerous tissues, the expression levels of circ_0008450 in OSCC tissues were significantly increased (P < 0.05), while miR-1294 levels were significantly decreased (P < 0.05). As compared to the Si-NC group, cell activity was significantly decreased (P < 0.05), the numbers of migrating and invading cells were significantly decreased (P < 0.05), and the protein levels of Ki-67, MMP-2, and MMP-9 were significantly decreased (P < 0.05) in the Si-circ_0008450 group. The results of the double luciferase assay confirmed targeted binding of circ_0008450 to miR-1294. As compared to the miR-NC group, cell activity was significantly decreased (P < 0.05) in the miR-1294 group, as were the numbers of migrating and invading cells (P < 0.05), and the protein levels of Ki-67, MMP-2, and MMP-9 (P < 0.05). As compared to the Si-circ_0008450+anti-miR-NC group, cell activity was significantly increased (P < 0.05) in the Si-circ_0008450+anti-miR-1294 group, as were the numbers of migrating and invading cells (P < 0.05), and the protein levels (P < 0.05) of Ki-67, MMP-2, and MMP-9. Interference with circ_0008450 reduced the invasion, migration, and proliferation of OSCC cells on account of upregulation via binding with miR-1294.

Immunohistochemical Expression of MMP-9, TIMP-1, and Vimentin and its Correlation With Inflammatory Reaction and Clinical Parameters in Oral Epithelial Dysplasia

The aim of this study was to investigate the immunoexpression of matrix metalloproteinase 9 (MMP-9), tissue inhibitor of metalloproteinase 1 (TIMP-1), and vimentin (VIM) and its association with the inflammatory reaction (IR) and clinical parameters in oral epithelial dysplasia (ED). The sample was composed of 66 cases of ED, 27 oral squamous cell carcinoma (OSCC), and 28 non-neoplastic epithelium (NNE). ED was graded according to the binary system as low-risk ED (n=42) and high-risk epithelial dysplasia (HRED: n=24). The IR was defined as the median number of inflammatory cells present on the connective tissue in 5 consecutive fields. Tissue sections of paraffin-embedded samples were immunohistochemically stained; MMP-9 and TIMP-1 expression was analyzed separately in the epithelium and the connective tissue; VIM was analyzed in the epithelium. Clinical parameters such as age, sex, lesion site and clinical presentation, alcohol/tobacco use, and malignant transformation of ED were retrospectively obtained from medical records. Nonhomogeneous leukoplakia presented higher odds (3.857; 95% confidence interval: 1.16-12.85) of being graded as HRED than did homogeneous lesions. The IR was higher in OSCC and ED than in NNE, and correlated with the epithelial expression of VIM. HRED and nonhomogeneous leukoplakias presented higher IR than did low-risk ED and homogeneous leukoplakias. Alcohol users had higher IR than nonalcohol users. Smokers had higher epithelial expression of MMP-9 and VIM. High IR in OSCC and HRED, and its positive correlation with VIM expression suggest a contribution of the IR in the progression of OSCC. Moreover, the high expression of MMP-9 and VIM in smokers implies its involvement in tobacco carcinogenesis.

Proteolytic Processing of CD44 and Its Implications in Cancer

CD44 is a transmembrane glycoprotein expressed in several healthy and tumor tissues. Modifications in its structure contribute differently to the activity of this molecule. One modification that has provoked interest is the consecutive cleavage of the CD44 extracellular ectodomain by enzymes that belong mainly to the family of metalloproteases. This process releases biologically active substrates, via alternative splice forms of CD44, that generate CD44v3 or v6 isoforms which participate in the transcriptional regulation of genes and proteins associated to signaling pathways involved in the development of cancer. These include the protooncogene tyrosine-protein kinase Src (c-Src)/signal transducer and activator of transcription 3 (STAT3), the epithelial growth factor receptor, the estrogen receptor, Wnt/βcatenin, or Hippo signaling pathways all of which are associated to cell proliferation, differentiation, or cancer progression. Whereas CD44 still remains as a very useful prognostic cell marker in different pathologies, the main topic is that the generation of CD44 intracellular fragments assists the regulation of transcriptional proteins involved in the cell cycle, cell metabolism, and most importantly, the regulation of some stem cell-associated markers.

Animal model and bioinformatics analyses suggest the TIMP1/MMP9 axis as a potential biomarker in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a common malignant tumor of the head and neck. However, the molecular mechanism underlying its development and progression is yet unclear. Genes that are differentially expressed, that is, differentially expressed genes (DEGs), between normal and diseased tissues are believed to be involved in disease development and progression. To identify the DEGs in OSCC and explore their role in occurrence and progression, we established a Chinese hamster OSCC model, determined the DEG, screened the identified DEGs, and performed Gene Ontology (GO) and KEGG enrichment analyses. A protein-protein interaction (PPI) network was generated to screen potential candidate genes. We then analyzed the expression, tumor stage and prognosis of candidate genes using the Gene Expression Profiling Interactive Analysis (GEPIA) database. Finally, we verified the candidate DEGs by quantitative real-time PCR and Gene Expression Omnibus analysis. The results showed 194 significantly DEGs, 140 enriched GO terms, and 8 KEGG pathways, which suggested that OSCC was closely related to the immune system, cell migration, and extracellular matrix. GEPIA and PPI network analysis revealed that SPP1, TNC, and ACTA1 were significantly related to tumor staging; SPP1, tissue inhibitors of matrix metallopeptidases (MMPs) 1 (TIMP1), and ACTA1 were closely related to prognosis. The scores for the top five highest degree genes were close, and the TIMP1/MMP9 axis appeared to be at the center of the PPI network, indicating that expression changes in the TIMP1/MMP9 axis and related genes may be involved in tumor invasion and metastasis. These findings provide novel insights into the mechanism of oral cancer.

The Landscape of Glycogen Synthase Kinase-3 Beta Genomic Alterations in Cancer

Glycogen synthase kinase-3β (GSK-3β), a serine/threonine kinase, has been implicated in the pathogenesis of many cancers, with involvement in cell-cycle regulation, apoptosis, and immune response. Small-molecule GSK-3β inhibitors are currently undergoing clinical investigation. Tumor sequencing has revealed genomic alterations in GSK-3β, yet an assessment of the genomic landscape in malignancies is lacking. This study assessed >100,000 tumors from two databases to analyze GSK-3β alterations. GSK-3β expression and immune cell infiltrate data were analyzed across cancer types, and programmed death-ligand 1 (PD-L1) expression was compared between GSK-3β-mutated and wild-type tumors. GSK-3β was mutated at a rate of 1%. The majority of mutated residues were in the kinase domain, with frequent mutations occurring in a GSK-3β substrate binding pocket. Uterine endometrioid carcinoma was the most commonly mutated (4%) tumor, and copy-number variations were most commonly observed in squamous histologies. Significant differences across cancer types for GSK-3β-mutated tumors were observed for B cells (P = 0.018), monocytes (P = 0.002), dendritic cells (P = 0.005), neutrophils (P = 0.0003), and endothelial cells (P = 0.014). GSK-3β mRNA expression was highest in melanoma. The frequency of PD-L1 expression was higher among GSK-3β-mutated tumors compared with wild type in colorectal cancer (P = 0.03), endometrial cancer (P = 0.05), melanoma (P = 0.02), ovarian carcinoma (P = 0.0001), and uterine sarcoma (P = 0.002). Overall, GSK-3β molecular alterations were detected in approximately 1% of solid tumors, tumors with GSK-3β mutations displayed a microenvironment with increased infiltration of B cells, and GSK-3β mutations were associated with increased PD-L1 expression in selected histologies. These results advance the understanding of GSK-3β complex signaling network interfacing with key pathways involved in carcinogenesis and immune response.

Hypothesis validation of rosiglitazone a potential inhibitor against glycogen synthase kinase-3β, for the management of multifaceted pathophysiology of the diabetic wound: An insilico study

Diabetic wound (DW) is a major complication of diabetes mellitus that often ends up with amputation of the concerned organ. The current therapies for DW include glucose regulation, wound debridement, pressure off-loading, surgeries, hyperbaric oxygen therapy, maggot therapy, and so on. However, the majority are not meeting all the prerequisites of DW because of extensive pathology and cost associated with the strategies. So, to overcome the problems related to the existing conventional therapies, we hypothesized to repurpose the current drugs, which can target a receptor having a considerable role in the progression of DW might be beneficial. One major challenge of DW is multifaceted pathophysiology includes prolonged inflammation, increased infections, decreased cell proliferation, and migration. Many shreds of evidence disclosed that inhibition of GSK-3β could result in reduced inflammation and infection, followed by increased cell proliferation and migration. Thus, we selected the GSK-3β receptor as a ubiquitous target for the treatment of multifactorial pathophysiology of DW. In the current hypothetical study, we investigated the use of rosiglitazone as a therapeutic modulator against the GSK-3β receptor. To validate our hypothesis, computational studies such as molecular docking and MMGBSA were performed. From the in silico methods, it is evident that rosiglitazone established a higher binding affinity against the selected receptor. Further, the Molecular Dynamic simulation study has revealed stable interaction of rosiglitazone against GSK-3β complex. Thus, rosiglitazone might be a drug of choice in the therapeutic management of DW.

Alterations and molecular targeting of the GSK-3 regulator, PI3K, in head and neck cancer

Head and neck squamous cell carcinoma (HNSCC) is a highly morbid, genetically unstable disease derived from the mucoepithelium of the upper aerodigestive tract. Recent characterization of this disease has implicated the PI3K-Akt-mTOR pathway as one of the most frequently dysregulated pathways. As such, there are several classes of PI3K inhibitors currently undergoing clinical trials. In this article, we review the PI3K pathway, mutations of this pathway in HNSCC, drugs that target PI3K, the impact of these agents on the PI3K and GSK-3 signaling axes, ongoing clinical trials evaluating PI3K inhibitors, and the challenges of using these drugs in the clinic. This article is part of a Special Issue entitled: GSK-3 and related kinases in cancer, neurological and other disorders edited by James McCubrey, Agnieszka Gizak and Dariusz Rakus.

Discovery of suppressors of CRMP2 phosphorylation reveals compounds that mimic the behavioral effects of lithium on amphetamine-induced hyperlocomotion

The effective treatment of bipolar disorder (BD) represents a significant unmet medical need. Although lithium remains a mainstay of treatment for BD, limited knowledge regarding how it modulates affective behavior has proven an obstacle to discovering more effective mood stabilizers with fewer adverse side effects. One potential mechanism of action of lithium is through inhibition of the serine/threonine protein kinase GSK3β, however, relevant substrates whose change in phosphorylation may mediate downstream changes in neuroplasticity remain poorly understood. Here, we used human induced pluripotent stem cell (hiPSC)-derived neuronal cells and stable isotope labeling by amino acids in cell culture (SILAC) along with quantitative mass spectrometry to identify global changes in the phosphoproteome upon inhibition of GSK3α/β with the highly selective, ATP-competitive inhibitor CHIR-99021. Comparison of phosphorylation changes to those induced by therapeutically relevant doses of lithium treatment led to the identification of collapsin response mediator protein 2 (CRMP2) as being highly sensitive to both treatments as well as an extended panel of structurally distinct GSK3α/β inhibitors. On this basis, a high-content image-based assay in hiPSC-derived neurons was developed to screen diverse compounds, including FDA-approved drugs, for their ability to mimic lithium's suppression of CRMP2 phosphorylation without directly inhibiting GSK3β kinase activity. Systemic administration of a subset of these CRMP2-phosphorylation suppressors were found to mimic lithium's attenuation of amphetamine-induced hyperlocomotion in mice. Taken together, these studies not only provide insights into the neural substrates regulated by lithium, but also provide novel human neuronal assays for supporting the development of mechanism-based therapeutics for BD and related neuropsychiatric disorders.

Association between immunohistochemical expression of matrix metalloproteinases and metastasis in oral squamous cell carcinoma: Systematic review and meta-analysis

BACKGROUND

The aim of this systematic review (SR) was to summarize and critically appraise available evidence on the association of the immunohistochemical expression of matrix metalloproteinases (MMPs) with the occurrence of lymph node/distant metastasis of oral squamous cell carcinoma (OSCC).

METHODS

Searches were conducted in five main electronic and three gray literature databases.

RESULTS

From 2128 records identified, 50 were included for qualitative analysis. A total of 12 MMPs were identified (-1, -2, -3, -7, -8, -9, -10, -11, -13, -25, -26, and MT1-MMP). Most included studies reported a positive association of MMP-1, -2, -3, -7, -9, and MT1-MMP with lymph node metastasis. MMP-8, -25, and -26 were not associated with lymph node metastasis.

CONCLUSIONS

According to this SR, MMP-1, -2, -3, -7, -9, and MT1-MMP seem to play an important role in lymph node metastasis of OSCC.

Identification of Candidate Biomarkers and Analysis of Prognostic Values in Oral Squamous Cell Carcinoma

Objectives: Oral squamous cell carcinoma (OSCC) is the most common oral cancer with a poor prognosis owing to limited understanding of the disease mechanisms. The aim of this study was to explore and identify the potential biomarkers in OSCC by integrated bioinformatics analysis.

Materials and Methods: Expression profiles of long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and messenger RNAs (mRNAs) were downloaded from The Cancer Genome Atlas (TCGA) and differentially expressed RNAs (DERNAs) were subsequently identified in OSCC by bioinformatics analysis. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were used to analyze DERNAs. Then, the competing endogenous RNA (ceRNA) network was constructed in Cytoscape and the protein -protein interaction (PPI) network was established in the STRING database. We established a risk model to predict the overall survival of OSCC on the basis of DElncRNAs with Kaplan–Meier analysis and combined with logrank p test. Furthermore, we identified potential biomarkers by combining univariate Cox regression with overall survival rate, which were then validated in Gene Expression Omnibus (GEO), OSCC cell lines and OSCC specimens.

Results: A total of 1,919 DEmRNAs, 286 DElncRNAs and 111 DEmiRNAs were found to be dysregulated in OSCC. A ceRNA network included 46 DElncRNAs,7 DEmiRNAs and 10 DEmRNAs, and the PPI network included 712 DEmRNAs including 31 hub genes. Moreover, a 7 lncRNAs risk model was established and four genes (CMA1, GNA14, HCG22, HOTTIP) were identified as biomarkers on overall survival in patients with OSCC.

Conclusions: This study successfully constructed a ceRNA network and a PPI network which play a crucial role in OSCC. A risk model was established to predict the prognosis, and four DERNAs are revealed with overall survival in patients with OSCC, suggesting that they may be potential biomarkers in tumor diagnosis and treatment.

Secreted amphiregulin promotes vincristine resistance in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is the most common type of oral cancer. Despite advances in surgery, radiotherapy and chemotherapy, the overall 5‑year survival rate of patients with OSCC has not significantly improved. In addition, the prognosis of patients with advanced‑stage OSCC remains poor. Therefore, it is necessary to develop novel therapeutic modalities. Vincristine (VCR), a naturally occurring vinca alkaloid, is a classical microtubule‑destabilizing agent and is widely used in the treatment of a number of cancers. Despite the proven antitumor benefits of VCR treatment, one of the major reasons for the failure of treatment is drug resistance. Changes in the tumor microenvironment are responsible for cross‑talk between cells, which may facilitate drug resistance in cancers; secreted proteins may promote communication between cancer cells to induce the development of resistance. To identify the secreted proteins involved in VCR resistance, conditioned media was obtained, and an antibody array was conducted to screen a comprehensive secretion profile between VCR‑resistant (SAS‑VCR) and parental (SAS) OSCC cell lines. The results showed that amphiregulin (AREG) was highly expressed and secreted in SAS‑VCR cells. Pretreatment with exogenous recombinant AREG markedly increased drug resistance against VCR in OSCC cells, as assessed by an MTT assay. Colony formation, MTT and western blot assays were performed to investigate the effects of AREG knockdown on VCR sensitivity. The results indicated that AREG expression can regulate VCR resistance in OSCC cells; overexpression of AREG increased VCR resistance in parental cells, whereas AREG knockdown decreased the VCR resistance of resistant cells. In addition, it was also demonstrated that the glycogen synthase kinase‑3β pathway may be involved in AREG‑induced VCR resistance. These findings may provide rationale to combine VCR with blockade of AREG‑related pathways for the effective treatment of OSCC.

ZO-2 Suppresses Cell Migration Mediated by a Reduction in Matrix Metalloproteinase 2 in Claudin-18-Expressing Lung Adenocarcinoma A549 Cells

Abnormal expression of the tight junctional components claudins (CLDNs) is observed in various malignant tissues. We reported recently that CLDN18 expression is down-regulated in human lung adenocarcinoma tissues. In the present study, we investigated the biological functions of CLDN18 using lung adenocarcinoma A549 cells. Microarray analysis showed that CLDN18 increases zonula occludens (ZO)-2 expression in A549 cells. The ectopic expression of CLDN18 increased nuclear ZO-2 levels, which were inhibited by N-[2-[[3-(4-bromophenyl)-2-propen-1-yl]amino]ethyl]5-isoquinolinesulfonamide (H-89), a nonspecific protein kinase A (PKA) inhibitor, but not by a PKA inhibitor 14-22 amide. In addition, dibutyryl cyclic adenosine monophosphate, an analogue of PKA, did not increase ZO-2 levels. These results suggest that H-89 sensitive factors without PKA are involved in the CLDN18-induced elevation of ZO-2. The cell cycle was affected by neither ZO-2 knockdown in CLDN18-expresssing A549 (CLDN18/A549) cells nor ZO-2 overexpression in A549 cells, suggesting that ZO-2 does not play an important role in the regulation of cell proliferation. The introduction of ZO-2 small interfering RNA (siRNA) into CLDN18/A549 cells increased migration, the expression and activity of matrix metalloproteinase 2 (MMP2), and the reporter activity of an MMP2 promoter construct. Furthermore, H-89 enhanced both mRNA levels and reporter activity of MMP2 in CLDN18/A549 cells. These results suggested that a reduction in CLDN18-dependent ZO-2 expression enhances MMP2 expression in lung adenocarcinoma cells, resulting in the promotion of the cell migration. CLDN18 may be a novel marker for metastasis in lung adenocarcinoma.

HSPD1 repressed E-cadherin expression to promote cell invasion and migration for poor prognosis in oral squamous cell carcinoma

Buccal mucosa squamous cell carcinoma (BMSCC) is one of major subsites of oral cancer and is associated with a high rate of metastasis and poor prognosis. Heat shock proteins (HSPs) act as potential prognostic biomarkers in many cancer types. However, the role of HSPD1 in oral cancer, especially in BMSCC, is still unknown. Through data analysis with The Cancer Genome Atlas (TCGA), we found the association of HSPD1 gene expression with tumorigenesis and poor prognosis in oral cancer patients. Our cohort study showed that higher HSPD1 protein level was associated with tumorigenesis and poor prognosis in BMSCC patients with lymph node invasion, suggesting that HSPD1 may be involved in tumor metastasis. Moreover, knockdown of HSPD1 induced E-cadherin expression and decreased the migration and invasion of BMSCC cells. In contrast, ectopic expression of HSPD1 diminished E-cadherin expression and promoted the migration/invasion of BMSCC cells. Further, HSPD1 regulated RelA activation to repress E-cadherin expression, enhancing the migration and invasion of BMSCC cells. Furthermore, HSPD1 protein level was inversely correlated with E-cadherin protein level in tumor tissues and co-expression of high HSPD1/low E-cadherin showed a significant association with poor prognosis in BMSCC patients. Taken together, HSPD1 might repress E-cadherin expression and promote metastatic characters of BMSCC cells for poor prognosis of BMSCC patients.

Crosstalk between Raf-MEK-ERK and PI3K-Akt-GSK3β signaling networks promotes chemoresistance, invasion/migration and stemness via expression of CD44 variants (v4 and v6) in oral cancer

BACKGROUND

The cell-surface glycoprotein CD44 is an important oral cancer stem cell (OCSC) marker and plays significant role in oral squamous cell carcinoma (OSCC) aggressiveness, however, the regulation of CD44 is incompletely understood.

METHODS

In the present study, 145 fresh human OSCC tissue specimens, including 18 adjacent normal, 42 noninvasive (N0), 53 invasive tumor samples (N_1-3) and 32 chemo-radiation resistant samples (RCRT), were included. The expression of CD44 standard (CD44s) and variants (CD44v4, CD44v6); the activation of pERK1/2, GSK3β, NICD (Notch) pathways; the cell viability; and the MMP-9/-2 activity were assessed using RT-PCR, immunohistochemistry, Western blotting, MTT assay and gelatin zymography. OSCC cell lines, including parental (SCC9/SCC4) and Cisplatin-resistant (CisR-SCC9/-SCC4) cells, were used. Knock down of CD44v4/CD44v6 (by siRNA) or inactivation of MAPK/PI3K pathways using specific PD98059/LY294002 was achieved for in vitro analysis of chemoresistance and invasion/migration.

RESULTS

Elevated CD44 variants were associated with overall OSCC progression, chemoresistance and invasion. Positive correlations were observed, mainly between the expression of CD44v4 and the activation of ERK1/2 causing chemoresistance, whereas CD44v6 expression and inactivation of GSK3β caused invasiveness of OSCC. Cisplatin resistant, CisR-SCC9/SCC4 cell lines showed OCSC properties. Inhibition of MEK/ERK1/2 by SMI or knock down (KD) of CD44v4 by siRNA reversed cisplatin-resistance, whereas blocking the PI3K/Akt/GSK3β pathway by SMI or KD of CD44v6 isoforms by respective siRNA diminished invasion/metastasis potential.

CONCLUSION

Collectively, our results demonstrated that CD44v4 expression is more linked with ERK1/2 activation and promote cisplatin resistance, whereas CD44v6 expression is associated primarily with PI3K/Akt/GSK3β activation and driving tumor invasion/migration.