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 (N1-3) 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-ß-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.

Glycogen synthase kinase-3ß 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 (CIN1-3 ), 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 CIN1-3 , 77.8% of the CSCC, and 89.7% of DRCT samples. Total and inactive GSK3ß 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 pGSK3ß expression (p = 0.013); E6 and CSCC progression (p < 0.0001)/drug resistance (p = 0.0001). CisR-HeLa/-SiHa was more dependent on pGSK3ß, 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 GSK3ß with nimbolide and iAkt can be exploited for therapeutic interventions of cervical cancer.

Glycogen synthase kinases: Moonlighting proteins with theranostic potential in cancer.

Glycogen synthase kinase-3 (GSK-3), a serine/threonine kinase is an archetypal multifunctional moonlighting protein involved in diverse cellular processes including metabolism, insulin signaling, proliferation, differentiation, apoptosis, neuronal function and embryonic development. The two known isoforms, GSK-3α and GSK-3ß that undergo activation/inactivation by post-translational, site-specific phosphorylation incorporate a vast number of substrates in their repertoire. Dysregulation of GSK-3 has been linked to diverse disease entities including cancer. The role of GSK-3 in cancer is paradoxical and enigmatic. The enzyme functions as a tumour promoter or suppressor based on the context, cell type and phosphorylation status. GSK-3 is the central hub that orchestrates signals from the Wnt/ß-catenin, PI3K/PTEN/Akt/mTOR, Ras/Raf/MEK/ERK, hedgehog, Notch and TP53 pathways to elicit regulatory influences on cancer initiation, epithelial-mesenchymal transition, and resistance to therapy. As a direct target of several microRNAs, GSK-3 influences hallmark attributes of cancer, cancer stemness and treatment resistance. There is overwhelming evidence to indicate that GSK-3 is aberrantly regulated in different cancer types. Consequently, GSK-3 has emerged as a potential therapeutic target in cancer. A plethora of natural and synthetic GSK-3 modulators have been discovered and the number of patents published for GSK-3 inhibitors has also been steadily increasing in recent years. This review focuses on the intricate interactions between GSK-3 and oncogenic signalling circuits as well as the feasibility of targeting GSK-3 for the treatment of cancer.

The elevated activation of NFκB and AP-1 is correlated with differential regulation of Bcl-2 and associated with oral squamous cell carcinoma progression and resistance.

OBJECTIVES: Oral cancer is the sixth most common cancer in the world. Failure of chemoradiation therapy is a major concern for treating oral cancer patients. The objective of this study is to determine the B cell lymphoma-2 (bcl-2) expression and its regulation by nuclear factor κB (NFκB) and activator protein 1 (AP-1) in oral cancer progression and chemoradiation resistance. MATERIALS AND METHODS: In the present study, a total of 123 (n = 123) human samples were included. Briefly, 64 fresh samples were from adjacent normal (AN), primary oral tumors without treatment (PT), and tumors with resistance to chemoradiation therapy with local recurrence (RCRT). Fifty-nine samples were human tongue cancers and normal samples (TMA). Messenger RNA (mRNA) expression levels of bcl-2 and protein levels of bcl-2, NFκB, AP-1, and inactive GSK3α/ß were measured by semiquantitative RT-PCR, immunohistochemistry, Western blot, and ChIP analysis. RESULTS: Increased bcl-2 expression was observed in PT compared to AN. The RCRT tumors showed maximum expression of bcl-2 mRNA and protein over the PT and AN groups. Bcl-2 protein and mRNA expression were positively correlated with NFκB and AP-1 expression. AP-1 expression was strongly correlated with bcl-2 in the RCRT group of tumors. Further, inactive GSK3α/ß showed a positive trend with bcl-2 expression in oral tongue cancer specimens. CONCLUSION: Collectively, our results demonstrated cumulative effect of AP-1 and NFĸB for bcl-2 gene regulation in overall PT progression and chemoradiation resistance. The study provides evidence of increased bcl-2 mRNA/protein fueled by NFĸB in PT and AP-1 in RCRT. These regulations of bcl-2 by NFκB and AP-1 are important in OSCC progression and chemoradiation resistance.

Reversion-inducing cysteine-rich protein with Kazal motifs and its regulation by glycogen synthase kinase 3 signaling in oral cancer.

The reversion-inducing cysteine-rich protein with Kazal motifs (RECK) and glycogen synthase kinase (GSK3) are novel tumor suppressors, and emerging evidence has suggested their active role in oral cancer pathogenesis. In the present study, 112 human samples, including 55 fresh samples of 14 adjacent normal tissues, 25 noninvasive oral tumors, and 18 invasive tumors, were included. The messenger RNA (mRNA) expression, protein expression, and promoter methylation of the RECK gene, as well as the expression of GSK3ß, phospho/total ß-catenin, and c-myc, were measured by RT-PCR, bisulphate modification-PCR, immunohistochemistry, and Western blot analysis. Additionally, ectopic expression of in/active GSK3ß was performed in cell culture experiments. This study provided information on the progressive silencing of RECK gene expression at the protein and mRNA levels paralleled with promoter hypermethylation at various stages of oral tumor invasion. RECK expression and the hypermethylation of the RECK gene promoter were negatively and positively correlated with pS9GSK3ß/c-myc expression, respectively. Further, a negative trend of RECK protein expression with nuclear ß-catenin expression was observed. Induced expression of active GSK3ß reversed the RECK silencing in SCC9 cells. Collectively, our results demonstrated that the silencing of the RECK gene, possibly regulated by the GSK3ß pathway, is an important event in oral cancer invasion and this pathway could be exploited for therapeutic interventions.

Expression and inactivation of glycogen synthase kinase 3 alpha/ beta and their association with the expression of cyclin D1 and p53 in oral squamous cell carcinoma progression.

BACKGROUND: The study aims to evaluate the expression and activity of glycogen synthase kinase 3 isoforms α/ß (GSK3α/ß) and to assess their oncogenic potential through a correlation with the expression of cyclin D1 and p53 in oral cancer. METHODS: The expression of total and phosphorylated GSK3α/ß as well as cyclin D1 and p53 together with their interaction were assessed in human oral cancer tissue samples, apparently normal adjacent tissues, benign tumor samples, premalignant lesions and healthy normal tissues (total 179) using various methods, such as immunohistochemistry, Western blot assays, immunoprecipitation and RT-PCR analysis. RESULTS: The expression of GSK3ß was significantly higher relative to GSK3α indicating the greater role of the ß isoform in oral cancer. Among various types of oral cancers, OSCC (of the lip and tongue) showed elevated expression of GSK3α/ß, and the expression was correlated with disease progression. The increased expression of pS(21)GSK3α and pS(9)GSK3ß not only correlated positively with cyclin D1 and p53 expression in tongue cancer progression but a gradual shift of their expression from the cytoplasmic to the nuclear compartment and overall disease severity was also observed. The interaction of GSK3ß-cyclin D1 and the positive correlation of pS(9)GSK3ß and the transcription of cyclin D1 were observed. CONCLUSIONS: These results demonstrate that the inactivation of GSK3ß is an important event in OSCC and can be used as a marker for assessing disease severity and may be exploited for therapeutic intervention.

Mixed-lineage kinase 3 phosphorylates prolyl-isomerase Pin1 to regulate its nuclear translocation and cellular function.

Nuclear protein peptidyl-prolyl isomerase Pin1-mediated prolyl isomerization is an essential and novel regulatory mechanism for protein phosphorylation. Therefore, tight regulation of Pin1 localization and catalytic activity is crucial for its normal nuclear functions. Pin1 is commonly dysregulated during oncogenesis and likely contributes to these pathologies; however, the mechanism(s) by which Pin1 catalytic activity and nuclear localization are increased is unknown. Here we demonstrate that mixed-lineage kinase 3 (MLK3), a MAP3K family member, phosphorylates Pin1 on a Ser138 site to increase its catalytic activity and nuclear translocation. This phosphorylation event drives the cell cycle and promotes cyclin D1 stability and centrosome amplification. Notably, Pin1 pSer138 is significantly up-regulated in breast tumors and is localized in the nucleus. These findings collectively suggest that the MLK3-Pin1 signaling cascade plays a critical role in regulating the cell cycle, centrosome numbers, and oncogenesis.

Oral tumor heterogeneity, its implications for patient monitoring and designing anti-cancer strategies.

Oral cancer tumors occur in the mouth and are mainly derived from oral mucosa linings. It is one of the most common and fatal malignant diseases worldwide. The intratumor heterogeneity (ITH) of oral cancerous tumor is vast, so it is challenging to study and interpret. Due to environmental selection pressures, ITH arises through diverse genetic, epigenetic, and metabolic alterations. The ITH also talks about peri-tumoral vascular/ lymphatic growth, perineural permeation, tumor necrosis, invasion, and clonal expansion/ the coexistence of multiple subclones in a single tumor. The heterogeneity offers tumors the adaptability to survive, induce growth/ metastasis, and, most importantly, escape antitumor therapy. Unfortunately, the ITH is prioritized less in determining disease pathology than the traditional TNM classifications or tumor grade. Understanding ITH is challenging, but with the advancement of technology, this ITH can be decoded. Tumor genomics, proteomics, metabolomics, and other modern analyses can provide vast information. This information in clinics can assist in understanding a tumor's severity and be used for diagnostic, prognostic, and therapeutic decision-making. Lastly, the oral tumor ITH can lead to individualized, targeted therapy strategies fighting against OC.

The Neem Limonoid Nimbolide Modulates Key Components of the DNA Damage Response Signalling in Cellular and Animal Models of Oral Squamous Cell Carcinoma

BACKGROUND: Deregulated DNA damage response (DDR) network is implicated in cancer progression and therapy resistance. OBJECTIVE: The present study was designed to investigate whether nimbolide, an anticancer neem limonoid, targets key components of the DDR signalling pathway in cellular and animal models of oral squamous cell carcinoma (OSCC). METHODS: OSCC cells (SCC-4 and SCC-9), 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch (HBP) carcinoma model, chemoresistant OSCC patient-derived xenograft (PDX) model established in athymic nude mice, and tissue sections from patients with oral premalignant/malignant disease were used for the study. Key molecules that orchestrate the DDR, including the MRN complex, ATM, DNA-PKcs, H2AX, and p53, were analysed by qRT-PCR, immunoblotting, immunofluorescence, and immunohistochemistry. Cell proliferation and apoptosis indices were evaluated. RESULTS: Nimbolide significantly reduced 8-oxodG levels, expression of MRN, ATMS1891, and γ-H2AX, with an increase in p-p53S15 in OSCC cells as well as in the HBP model. Nimbolide potentiated the effect of KU-55933 in ATM inhibition. In the PDX model, nimbolide suppressed tumor formation, stimulated DDR and apoptosis, inhibited cell proliferation, and enhanced sensitivity to cisplatin. Analysis of p-ATM expression revealed a significant increase during the sequential progression of hamster and human OSCC. CONCLUSIONS: This study provides compelling evidence that nimbolide functions as a DDR inhibitor in cellular and hamster OSCC models and as a DDR activator in the PDX model primarily by targeting ATM. Small molecules like nimbolide that modulate DDR are of immense benefit in cancer therapy. The study has also unveiled p-ATM as a promising biomarker of tumour progression in human OSCCs.

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.

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.

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.

Reciprocal regulation of AKT and MAP kinase dictates virus-host cell fusion.

Viruses of the Paramyxoviridae family bind to their host cells by using hemagglutinin-neuraminidase (HN), which enhances fusion protein (F)-mediated membrane fusion. Although respiratory syncytial virus and parainfluenza virus 5 of this family are suggested to trigger host cell signaling during infection, the virus-induced intracellular signals dictating virus-cell fusion await elucidation. Using an F- or HN-F-containing reconstituted envelope of Sendai virus, another paramyxovirus, we revealed the role and regulation of AKT1 and Raf/MEK/ERK cascades during viral fusion with liver cells. Our observation that extracellular signal-regulated kinase (ERK) activation promotes viral fusion via ezrin-mediated cytoskeletal rearrangements, whereas AKT1 attenuates fusion by promoting phosphorylation of F protein, indicates a counteractive regulation of viral fusion by reciprocal activation of AKT1 and mitogen-activated protein kinase (MAPK) cascades, establishing a novel conceptual framework for a 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.

Nimbolide, a Neem Limonoid, Is a Promising Candidate for the Anticancer Drug Arsenal.

Nimbolide, a major limonoid constituent of Azadirachta indica, commonly known as neem, has attracted increasing research attention owing to its wide spectrum of pharmacological properties, predominantly anticancer activity. Nimbolide is reported to exert potent antiproliferative effects on a myriad cancer cell lines and chemotherapeutic efficacy in preclinical animal tumor models. The potentiality of nimbolide to circumvent multidrug resistance and aid in targeted protein degradation broaden its utility in enhancing therapeutic modalities and outcome. Accumulating evidence indicates that nimbolide prevents the acquisition of cancer hallmarks such as sustained proliferation, apoptosis evasion, invasion, angiogenesis, metastasis, and inflammation by modulating kinase-driven oncogenic signaling networks. Nimbolide has been demonstrated to abrogate aberrant activation of cellular signaling by influencing the subcellular localization of transcription factors and phosphorylation of kinases in addition to influencing the epigenome. Nimbolide, with its ever-expanding repertoire of molecular targets, is a valuable addition to the anticancer drug arsenal.

Glycogen synthase kinase 3 beta: can it be a target for oral cancer.

Despite progress in treatment approaches for oral cancer, there has been only modest improvement in patient outcomes in the past three decades. The frequent treatment failure is due to the failure to control tumor recurrence and metastasis. These failures suggest that new targets should be identified to reverse oral epithelial dysplastic lesions. Recent developments suggest an active role of glycogen synthase kinase 3 beta (GSK3 beta) in various human cancers either as a tumor suppressor or as a tumor promoter. GSK3beta is a Ser/Thr protein kinase, and there is emerging evidence that it is a tumor suppressor in oral cancer. The evidence suggests a link between key players in oral cancer that control transcription, accelerated cell cycle progression, activation of invasion/metastasis and anti-apoptosis, and regulation of these factors by GSK3beta. Moreover, the major upstream kinases of GSK3beta and their oncogenic activation by several etiological agents of oral cancer support this hypothesis. In spite of all this evidence, a detailed analysis of the role of GSK3beta in oral cancer and of its therapeutic potential has yet to be conducted by the scientific community. The focus of this review is to discuss the multitude of roles of GSK3beta, its possible role in controlling different oncogenic events and how it can be targeted in oral cancer.

Polymorphisms and haplotypes of TLR4, TLR9 and CYP1A1 genes possibly interfere with high-risk human papillomavirus infection and cervical cancer susceptibility in Jharkhand, India.

BACKGROUND: Expression and single nucleotide polymorphisms (SNPs) of TLR4/9 and CYP1A1 genes are vital for cervical squamous cell carcinoma (CSCC) but considerably vary in different populations. METHODS: A total of 255-subjects from Jharkhand (130-cases, 125-controls) were utilized to obtain the expression/SNP status of TLR4/9, CYP1A1, and E6 (HPV16/18) by RT-PCR, WB, and allele-specific-PCR followed by sequencing. RESULTS: Over-expression of TLR4/9 and high infection of HPV16/18(78.5%) were found to be associated with CSCC. Among the seven SNPs(p1-p7) tested, the CT-genotype (p3:rs1927911; OR = 2.142; p = 0.004) and 'T'-allele (p3; OR = 1.694; p = 0.0061) of TLR4; CC-genotype (p4:rs5743836; OR = 3.307; p = 0.0018), 'C'-allele (p4; OR = 1.895; p = 0.0009), GA-genotype (p5:rs352140; OR = 2.064; p = 0.0172), AA-genotype (p5; OR = 2.602; p = 0.0021) and 'A'-allele (p5; OR = 1.939; p = 0.0002) of TLR9; and the TC-genotype (p6:rs4646903; OR = 1.967; p = 0.0452) and GG-genotype (p7:rs1048943; OR = 2.336; p = 0.0287) and 'G'-allele (p7; OR = 1.685; p = 0.0082) of CYP1A1 were associated with an increased-risk of CSCC. Similarly, the p3:CT-genotype (OR = 1.993; p = 0.0134); p4:CC-genotype (OR = 3.071; p = 0.0057) and 'C'-allele (OR = 1.838; p = 0.0029); p5:AA-genotype (OR = 2.231; p = 0.0147) and 'A'-allele (OR = 1.756; p = 0.0032); p6:TC-genotype (OR = 2.370; p = 0.02); and the p7:GG-genotype (OR = 2.255; p = 0.0488) and 'G'-allele (OR = 1.691; p = 0.0118) showed an association with HPV16/18 infection. Conversely, TLR4 (p1-p2-p3:A-G-T; OR = 3.361; p = 0.029), TLR9 (p4-p5:C-A; OR = 1.786; p = 0.032) and CYP1A1 (p6-p7:C-G; OR = 1.783; p = 0.033) haplotypes with CSCC susceptibility was observed, whereas the TLR4 (p1-p2-p3:A-C-C; OR = 0.4675; p = 8.E-3) and TLR9 (p4-p5:T-G; OR = 0.3937; p = 0.00) haplotypes showed protection against the development of CSCC. Further, though p1:rs10759931 and p2:rs11536889 were found to be insignificant, the p3:CT-genotype, p5:GA/AA-genotype, and p7:GG-genotype were associated with elevated protein; the p4:CC-genotype and p6:TC-genotype were associated with increased mRNA compared to their respective-wild-type-groups. CONCLUSION: The present study revealed an association between TLR4/9 and CYP1A1 polymorphisms with increased HPV16/18 infection susceptibility and CSCC risk among the women of Jharkhand state.

Pluripotency transcription factor Nanog and its association with overall oral squamous cell carcinoma progression, cisplatin-resistance, invasion and stemness acquisition.

BACKGROUND: Cisplatin-resistant oral squamous cell carcinoma (OSCC) cells acquire stem-like characteristics and are difficult to treat. Nanog is a transcription factor and needed for maintenance of pluripotency, but its transcription-promoting role in OSCC progression and cisplatin resistance is poorly understood. METHODS: Here, 110 fresh human tissue specimens of various stages, including invasive (N1-3 )/chemoradiation-resistant OSCC samples, cisplatin-resistant (CisR-SCC-4/-9) OSCC cells/parental cells, photochemical ECGC, and siRNA (Nanog) were used. RESULTS: Nanog overexpression was associated with overall progression, chemoresistance, and invasion of OSCC. Nanog recruitment to c-Myc, Slug, E-cadherin, and Oct-4 gene promoter was observed. Positive correlation of Nanog protein expression with c-Myc, Slug, cyclin D1, MMP-2/-9, and Oct-4 and negative correlation with E-cadherin gene expression were found. Knockdown of Nanog and treatment of epicatechin-3-gallate reversed cisplatin resistance and diminished invasion/migration potential. CONCLUSION: Nanog directly participated in the regulation of Slug, E-cadherin, Oct-4, and c-Myc genes, causing cisplatin resistance/recurrence of OSCC.

Correction: Mixed lineage kinase 3 promotes breast tumorigenesis via phosphorylation and activation of p21-activated kinase 1.

The original version of this Article did not acknowledge Pradeep Sathyanarayana as an author. His affiliation is Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine, USA.