Neuronal CFL1 upregulation in head and neck squamous cell carcinoma enhances tumor-nerve crosstalk and promotes tumor growth.

Head and neck squamous cell carcinoma (HNSCC) is a prevalent cancer type, marked by a pronounced nerve density within the tumor microenvironment and a high rate of perineural invasion (PNI). Growing evidence suggests that the nervous system plays a vital role in HNSCC progression. Yet, the mechanisms governing cancer-nerve interactions remain largely elusive. Our research revealed that cofilin-1 (CFL1) is significantly overexpressed in HNSCC and correlates with both PNI and unfavorable prognosis. Utilizing multiplex fluorescent immunohistochemistry, we have localized CFL1 chiefly to the nerves adjacent to tumor sites. Significantly, it is the elevated expression of CFL1 in neuronal structures, rather than in the tumor cells, that aligns with diminished patient survival rates. We observed that HNSCC cells induced the expression of neuronal CFL1 and that the conditional knockout of neuronal CFL1 impedes tumor-nerve interactions. Both Gene Ontology functional enrichment analyses and Gene Set Enrichment Analysis demonstrate that CFL1 expression in HNSCC is associated with specific biological processes, including "RIBOSOME," "PROTEASOME," and "cadherin binding." In summary, HNSCC promotes the expression of CFL1 in nerves, which is essential for cancer-nerve interactions. The neuronal CFL1 is associated with PNI and may be a potential molecular prognostic marker of poor survival in HNSCC.

CircMAT2B facilitates the progression of head and neck squamous cell carcinoma via sponging miR-491-5p to trigger ASCT2-mediated glutaminolysis.

Circular RNAs (circRNAs) are well-known to exert significant roles in regulating the pathological processes, including human carcinogenesis. Currently, less is known about their exact roles in head and neck squamous cell carcinoma (HNSCC). Herein, we aimed to investigate and validate the role of a novel circRNA, circMAT2B, as well as its potential molecular mechanism in HNSCC progression. A cohort of 41 paired of HNSCC tumor tissues and adjacent normal tissues from HNSCC patients were collected. Further, we characterized circMAT2B expression patterns in HNSCC tissues and cell lines, as well as exploring its association with the prognosis of HNSCC patients. Biological functions on cell proliferation, apoptosis, migration, and invasion were assessed using Cell Counting Kit-8, EdU incorporation, TUNEL, wound healing, and transwell assays. Glutaminolysis was evaluated by measuring glutamine, glutamate, and α-ketoglutarate (α-KG) levels. The regulatory network of circMAT2B/miR-491-5p/ASCT2 axis was verified by RNA immunoprecipitation and luciferase reporter assays. Western blot was conducted to detect the level of ASCT2 and GLS1. Remarkably overexpressed circMAT2B was observed in HNSCC tissues and cell lines, of which high abundance was positively correlated with patients' poor prognosis. Silencing of circMAT2B inhibited cell proliferation, migration, and invasion, as well as glutaminolysis. miR-491-5p, interacted with ASCT2, was identified to be a downstream target of circMAT2B, thereby involving in circMAT2B-mediated biological effects. In summary, we draw a conclusion that circMAT2B could modulate the processes of cell proliferation, migration, invasion, and glutaminolysis of HNSCC cells partly via the miR-491-5p/ASCT2 axis by a molecular mechanism of competing endogenous RNA (ceRNA), implying an underlying circRNA-targeted therapy for HNSCC treatment.

A Circular RNA, hsa_circ_0018180 (circPARD3), Triggers Glycolysis and Promotes Malignancy of Head and Neck Squamous Cell Carcinoma Through the miR-5194/ENO1 Axis.

Emerging evidence has demonstrated the pivotal roles of circular RNAs (circRNAs) in the modulation of malignancy and pathological progression among multiple human cancers. Glucose metabolism reprogramming is a widely identified characteristic for contributing to facilitate tumorigenesis. Nonetheless, their contributions to head and neck squamous cell carcinoma (HNSCC) cell glycolysis remain to be further elucidated. Herein, we aim to investigate the role of circRNA, hsa_circ_0018180 (also named as circPARD3) in HNSCC. Expression patterns of circPARD3 in HNSCC tissues and different cell lines were determined by qRT-PCR assay, as well as its correlation with the prognosis of survival. CCK-8, EdU incorporation, and transwell assays were carried out to assess the cell viability, proliferation, migration, and invasion, respectively. Glucose uptake and lactate production were evaluated by preforming glycolysis. Mechanistically, the circPARD3/miR-5194/ENO1 axis was verified by RNA immunoprecipitation (RIP) and luciferase reporter assays. Western blot analysis was employed to measure the epithelial-mesenchymal transition (EMT)-associated biomarkers. Upregulated circPARD3 observed in HNSCC tissues and cell lines indicated the poor prognosis of patients. Stable knockdown of circPARD3 dramatically exerted the suppressive effects on cell viability, proliferation, migration, and invasion, as well as glucose uptake and lactate production. Mechanistically, circPARD3 harbored miR-5194, serving as a miRNA sponge, thereby increasing ENO1 expression. Moreover, ENO1 evidently reversed miR-5194-mediated attenuated malignant behaviors. Collectively, our study identified an oncogenic role of circPARD3 in HNSCC through a novel machinery of circPARD3/miR-5194/ENO1 and provided a promising therapeutic target for HNSCC.

ASCT2 (SLC1A5)-dependent glutamine uptake is involved in the progression of head and neck squamous cell carcinoma.

BACKGROUND: Glutamine is an abundant and versatile nutrient in cancer cells. Head and neck squamous cell carcinoma (HNSCC) was reported to be dependent on mainly glucose, not glutamine, for producing the energy required for survival and proliferation. METHODS: The roles of ASCT2 (SLC1A5) and associated glutamine metabolism were determined by the MTT, colony formation, glutamine uptake, intracellular glutathione, ROS detection, immunofluorescence, immunohistochemistry, and apoptosis enzyme-linked immunosorbent assays as well as animal studies. RESULTS: We found that glutamine is also critical for HNSCC. In this study, ASCT2, an amino acid transporter responsible for glutamine transport, in addition to LAT1 and GLS, is overexpressed in HNSCC and associated with poor survival. Using both in vivo and in vitro models, we found that knocking down ASCT2 by shRNAs or miR-137 or the combination of silencing ASCT2 and pharmacologically inhibiting SNAT2 via a small-molecule antagonist called V-9302 significantly suppressed intracellular glutamine levels and downstream glutamine metabolism, including glutathione production; these effects attenuated growth and proliferation, increased apoptosis and autophagy, and increased oxidative stress and mTORC1 pathway suppression in HNSCC. Additionally, silencing ASCT2 improved the response to cetuximab in HNSCC. CONCLUSIONS: In summary, ASCT2-dependent glutamine uptake and subsequent glutamine metabolism are essential for HNSCC tumorigenesis, and the combination of glutamine uptake inhibitors and cetuximab presents a promising strategy for improving the outcomes of HNSCC patients.

An indispensable role of CPT-1a to survive cancer cells during energy stress through rewiring cancer metabolism.

Unlike normal cells, cancer cells are recently identified to rely on aerobic glycolysis for energy production called the Warburg effect. Several attempts are being made to target this metabolic reprogramming pathway in treating cancers; however, the successful rate is very limited. In this study, we investigated the functional roles of fatty acid oxidation key enzyme carnitine palmitoyl transferase 1a (CPT-1a), during the metabolic programming of pancreatic ductal adenocarcinoma (PDAC) cells induced by glucose deprivation. Knockdown of CPT-1a decreased the intracellular nicotinamide adenine dinucleotide phosphate (NADPH) and glutathione (GSH) generation, increased reactive oxygen species (ROS) production, and induced sensitivity to glucose deprivation, whereas upregulation of CPT-1a increased the intracellular ATP required for cell survival. Further investigation showed that CPT-1a inhibitor etomoxir (ETO) can restore the sensitivity of PDAC cells to gemcitabine and regress xenograft tumors in vivo. Finally, overexpression of CPT-1a expression is associated with chemoresistance in tumor specimens. Our data suggest that CPT-1a plays a key role in reprogramming cancer metabolism to escape from energy stress.

Attention switching through text dissimilarity: a cognition research on fragmented reading behavior.

People tend to obtain information through fragmented reading. However, this behavior itself might lead to distraction and affect cognitive ability. To address it, it is necessary to understand how fragmented reading behavior influences readers' attention switching. In this study, the researchers first collected online news that had 6 theme words and 60 sentences to compose the experimental material, then defined the degree of text dissimilarity, used to measure the degree of attention switching based on the differences in text content, and conducted an EEG experiment based on P200. The results showed that even after reading the fragmented text content with the same overall content, people in subsequent cognitive tasks had more working memory capacity, lower working memory load, and less negative impact on cognitive ability with the text content with lower text dissimilarity. Additionally, attention switching caused by differences in concept or working memory representation of text content might be the key factor affecting cognitive ability in fragmented reading behavior. The findings disclosed the relation between cognitive ability and fragmented reading and attention switching, opening a new perspective on the method of text dissimilarity. This study provides some references on how to reduce the negative impact of fragmented reading on cognitive ability on new media platforms.

A review on the use of porcine in tendon research.

PURPOSE OF REVIEW: Large animals have been increasingly employed in tendon research; the objective of this review was to summarize the employment of porcine in tendon research. RECENT FINDINGS: Literature before 2022-03-31 was searched using the following strategy: (pig[MeSH Terms]) AND (tendon[MeSH Terms]); (pig[MeSH Terms]) AND (tendon[title]); (tendon[MeSH Terms]) AND (porcine[title]); (tendon[title]) AND (porcine[title]); (tendon[MeSH Terms]) AND (pig[title]); (tendon[title]) AND (pig[title]); (tendon[MeSH Terms]) AND (swine[title]); (tendon[title]) AND (swine[title]). 296 studies were included in this review. There were wide application areas of porcine tendon, including tissue engineering tendons, training of surgical skills. Porcine tendon was used both in in vitro studies, such as anatomy, biomechanics, cytology, and material science as well as in in vivo studies. The research techniques of porcine tendon are relatively common. SUMMARY: In conclusion, pigs have been widely used as a good animal model of tendon research. However, the limitations of porcine tendon research (the lack of anatomical research and in vivo studies) should be given more attention in future studies.

Anti-Anaplastic Thyroid Cancer (ATC) Effects and Mechanisms of PLX3397 (Pexidartinib), a Multi-Targeted Tyrosine Kinase Inhibitor (TKI).

Background Anaplastic thyroid cancer (ATC) is the greatest lethal thyroid neoplasm with a low incidence and lacks an effective treatment strategy and standardized treatment protocol. PLX3397 (Pexidartinib) is an FDA-approved multitarget tyrosine kinase inhibitor. The research is designed to explore the possible anti-proliferative activity of pexidartinib on ATC, as well as its related molecular mechanisms. Methods The cell viability was assessed by CCK-8, LDH release, colony formation, and EdU detection assays. Apoptosis and the alteration on cell cycle arrest were characterized by flow cytometry (FCM). ER stress was evaluated by immunofluorescence (IF). ROS levels were determined by flow cytometry. Western blot assays were conducted to evaluate changes in key molecules related to apoptosis and ER stress. The ATC xenografts model was established, and immunohistochemistry was performed to validate the anti-ATC effects of pexidartinib in vivo. Results Pexidartinib significantly inhibited ATC cell proliferation and induced apoptosis and cell cycle arrest. Moreover, pexidartinib potently induced ER stress and elevated ROS in ATC cells, and the apoptotic cells and ER stress in ATC after administration of pexidartinib could be reversed by an ER stress inhibitor and ROS scavenger, respectively. Furthermore, pexidartinib treatment induced Nrf2 accumulation in nuclei and reduced the interaction of Nrf2 with Keap-1, and knockdown of Nrf2 enhanced the anti-ATC effects of pexidartinib in vitro. In addition, pexidartinib significantly inhibited ATC xenograft growth and proliferation in vivo, and the combination of ML385, an Nrf2 inhibitor, potently enhanced the anti-ATC effects of pexidartinib in vivo. Conclusion Our findings suggest pexidartinib is a potential agent for treating ATC. Co-administration with an Nrf2 inhibitor is an effective synergistic strategy.

Phosphorylation of MICAL2 by ARG promotes head and neck cancer tumorigenesis by regulating skeletal rearrangement.

The actin cytoskeletal architecture provides the structural underpinnings for crucial cellular behaviors. In cancer cells, changes in the actin cytoskeleton may serve as prerequisites for proliferation, invasion, and metastatic dissemination. However, the underlying mechanisms remain largely unknown. Here, we show that MICAL2, which is increased in head and neck squamous cell carcinoma (HNSCC) and inversely associated with patient survival, promotes HNSCC growth, invasion, and migration. MICAL2 serves as a flavoprotein monooxygenase and directly induces actin filament depolymerization by specifically oxidizing the methionine 44 and 47 residues of F-actin. The kinase ARG interacts with MICAL2 and augments MICAL2-mediated actin disassembly. Direct phosphorylation assay and mass spectrometry confirmed that ARG phosphorylates MICAL2 at Tyr445, Tyr463, and Tyr488. Substitution of the Tyr445 or Tyr463 residue of purified recombinant MICAL2-redox with phenylalanine (generating a non-phosphorylatable mutant) abolishes the enhanced MICAL2-mediated F-actin disassembly induced by ARG. Consistently, ectopic expression of non-phosphorylatable MICAL2 mutants (MICAL2Y445F and MICAL2Y463F, not MICAL2Y488F) failed to ameliorate HNSCC cell growth, whereas expression of wild-type MICAL2 or MICAL2Y488F rescued the impaired proliferation induced by MICAL2 knockdown. Moreover, CCG-1423, an inhibitor of MICAL2, was shown to inhibit HNSCC cell proliferation, invasion, and migration. Taken together, our findings indicate that phosphorylation of MICAL2 at Tyr445 and Tyr463 by ARG mediates F-actin disassembly and promotes HNSCC progression.

CAV2 promotes the invasion and metastasis of head and neck squamous cell carcinomas by regulating S100 proteins.

More than half of HNSCC patients are diagnosed with advanced disease. Locally advanced HNSCC is characterized by tumors with marked local invasion and evidence of metastasis to regional lymph nodes. CAV2 is a major coat protein of caveolins, important components of the plasma membrane. In this study, CAV2 was found to profoundly promote invasion and stimulate metastasis in vivo and in vitro. CAV2 was demonstrated to be a key regulator of S100 protein expression that upregulates the proteins levels of S100s, which promotes the invasion and migration and downregulates the expression of tumor suppressors. Mechanistically, CAV2 directly interacts with S100s in HNSCC cells, and CAV2 reduces S100A14 protein expression by promoting its ubiquitylation and subsequent degradation via the proteasome. Moreover, we discovered that CAV2 promotes the interaction between S100A14 and the E3 ubiquitin ligase TRIM29 and increases TRIM29 expression. Taken together, our findings indicate that CAV2 promotes HNSCC invasion and metastasis by regulating the expression of S100 proteins, presenting a novel potential target for anticancer therapy in HNSCC.

Correction: Prediction of survival prognosis of non-small cell lung cancer by APE1 through regulation of epithelial-mesenchymal transition.

[This corrects the article DOI: 10.18632/oncotarget.8660.].

BCAR3 promotes head and neck cancer growth and is associated with poor prognosis.

Breast cancer anti-estrogen resistance protein 3 (BCAR3) is involved in anti-estrogen resistance and other important aspects of breast cancer. However, the role of BCAR3 in other solid tumors remains unclear. The relationship between the clinicopathologic characteristics of head and neck squamous cell carcinoma (HNSCC) patients and BCAR3 was analyzed using the Wilcoxon's signed-rank test and logistic regression. The association between BCAR3 expression and clinicopathologic features and survival was analyzed using Cox regression and the Kaplan-Meier method. In vivo and in vitro assays were performed to validate the effect of BCAR3 on HNSCC growth. BCAR3-related mRNAs were determined by calculating the Pearson's correlation coefficient based on The Cancer Genome Atlas (TCGA). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses, and gene set enrichment analysis (GSEA) were used to predict the potential functions of BCAR3. BCAR3 expression is overexpressed in HNSCC and was shown to be associated with perineural invasion (PNI) and poor survival. BCAR3 silencing significantly attenuated the proliferation of HNSCC cells, whereas BCAR3 depletion inhibited tumor growth in vitro. GO and KEGG functional enrichment analyses, and GSEA showed that BCAR3 expression in HNSCC was associated with biological processes, such as cell adhesion, actin binding, cadherin binding, and angiogenesis. BCAR3, which promotes HNSCC growth, is associated with perineural invasion and may be a potential molecular prognostic marker of poor survival in HNSCC.

[Influencing factors for intrahepatic distant recurrence of liver cancer after radiofrequency ablation].

OBJECTIVE: To analyze the influencing factors affecting intrahepatic distant recurrence after radiofrequency ablation (RFA) for primary hepatic cancer. METHODS: Eighty patients with primary hepatic tumors underwent RFA treatment between January 2002 and June 2005 were retrospectively analyzed. There were 49 males and 31 females aged from 34 to 84 years old. The tumor size was less than 5 cm and no more than 3 nodules. Univariate analysis and multivariate analysis were used to evaluate the risk factors for intrahepatic distant recurrence after RFA. RESULTS: The cumulative rates of intrahepatic distant recurrence were 6.3%, 32.0%, and 67.3% at 1, 3, and 5 years, respectively. Univariate analysis revealed that pretreatment serum AFP level of >or= 50 microg/L (P = 0.029), decarboxy prothrombin (DCP) level of >or= 40 mAu/ml (P = 0.004), ablative margin of < 1 cm (P = 0.035), prothrombin time activity percent target of < 70% (P = 0.012), and poor Child-Pugh grade (P = 0.002) were related to intrahepatic distant recurrence. A multivariate analysis revealed that pretreatment serum AFP and DCP level, ablative margin and Child-Pugh grade were independent risk factors for intrahepatic distant recurrence. CONCLUSIONS: Primary liver cancer patients with high serum AFP, DCP and poor Child-Pugh grade before RFA should be carefully followed up to monitor any intrahepatic distant recurrence. A sufficient ablative margin in RFA for primary liver cancer is required to prevent recurrence.

Clinical characteristics and prognostic analysis of ipsilateral supraclavicular lymph node metastases in breast cancer patients: a retrospective study.

BACKGROUND: To investigate the clinical characteristics and prognosis of different subtype breast cancer patients with pathologically proven ipsilateral supraclavicular lymph node metastasis (ISCLM). METHODS: We performed a retrospective analysis of clinical data for total 156 patients who diagnosed with ISCLM, among 3,133 breast cancer patients. Breast cancer subtypes were classified as hormone receptor (HR) positive (+)/human epidermal growth factor receptor 2 (HER2) negative (-), HR+/HER2+, HR-/HER2+ and triple-negative breast cancer (TNBC) subtypes using immunohistochemical staining. We subsequently analyzed matched cohorts, evaluating clinical features and survival in different subtypes. RESULTS: The patients in this study accounted for 5% of all breast cancer patients treated during the same period. Breast cancer subtypes were confirmed in all 156 patients (39.7% with HR+/HER2-, 23.7% with HR+/HER2+, 14.7% with HR-/HER2+, and 21.8% with TNBC). The median overall survival after ISCLM was 47 months (95% confidence interval (CI), 3-94 months), and the overall 1-, 3- and 5-year survival rates were 92.3, 73.7 and 48.1%, respectively. We found that the survival rate is impacted by breast cancer subtypes (P = 0.001), and patients with TNBC had the shortest survival. Time to ISCLM less than 24 months and ISCLM size > 3 cm were independent predictors of poor survival in patients with ISCLM (P = 0.007 and 0.001, respectively). CONCLUSIONS: Clinical breast cancer subtypes were still independent prognostic predictors among breast cancer patients with ISCLM. ISCLM arising from TNBC has the worst prognosis. Multidisciplinary therapy is beneficial for breast cancer patients with ISCLM.

SEMA3C Promotes Cervical Cancer Growth and Is Associated With Poor Prognosis.

Introduction: Aberrant activation of Semaphorin3C(SEMA3C) is widespread in human cancers. We aimed to analyze SEMA3C expression in cervical cancer and investigate the role of SEMA3C in cervical cancer and its underlying mechanism, which is important for exploring new therapeutic targets and prognostic factors. Materials and Methods: The expression of SEMA3C was examined in paraffin-embedded cervical cancer specimens. In vivo and in vitro assays were performed to validate the effect of SEMA3C on cervical cancer cell proliferation and p-ERK pathway activation. Gene Set Enrichment Analysis (GSEA) was performed using The Cancer Genome Atlas (TCGA) data set. Results: SEMA3C expression was associated with poor survival in both the TCGA cohort and our cohort. Silencing of SEMA3C suppressed cervical cancer cell proliferation, colony formation ability, and the activation of the p-ERK signaling pathway in vitro. SEMA3C depletion inhibited tumor growth in vitro. GSEA also showed that the epithelial mesenchymal transition (EMT), TGFß signaling pathway, angiogenesis, and extracellular matrix (ECM) receptor interactions are associated with a high SEMA3C expression phenotype. Conclusion: SEMA3C is correlated with poor prognosis of cervical cancer patients and promotes tumor growth via the activation of the p-ERK pathway.

Integrating Clinical and Genetic Analysis of Perineural Invasion in Head and Neck Squamous Cell Carcinoma.

Introduction: Perineural invasion (PNI), a key pathological feature of head and neck squamous cell carcinoma (HNSCC), predicts poor survival. However, the associated clinical characteristics remain uncertain, and the molecular mechanisms are largely unknown. Materials and methods: HNSCC gene expression and corresponding clinical data were downloaded from The Cancer Genome Atlas (TCGA). Prognostic subgroup analysis was performed, and potential PNI risk factors were assessed with logistic regression. PNI-associated gene coexpression modules were identified with weighted gene coexpression network analysis (WGCNA), and key module gene functions and the roles of non-malignant cells in PNI were evaluated with a single-cell transcriptomic dataset (GSE103322). Results: PNI was significantly inversely associated with overall survival (HR, 2.08; 95% CI, 1.27 to 3.40; P = 0.004), especially in advanced patients (HR, 2.62; 95% CI, 1.48 to 4.64; P < 0.001). Age, gender, smoking history, and alcohol history were not risk factors. HPV-positive cases were less likely than HPV-negative cases to develop PNI (OR, 0.28; 95% CI, 0.09 to 0.76; P = 0.017). WGCNA identified a unique significantly PNI-associated coexpression module containing 357 genes, with 12 hub genes (TIMP2, MIR198, LAMA4, FAM198B, MIR4649, COL5A1, COL1A2, OLFML2B, MMP2, FBN1, ADAM12, and PDGFRB). Single-cell transcriptomic data analysis revealed that the genes in the PNI-associated module correlated with the signatures "EMT," "metastasis," and "invasion." Among non-malignant cells, fibroblasts had relatively high expression of the key genes. Conclusion: At the molecular and omic levels, we verified that PNI in HNSCC is a process of invasion rather than simple diffusion. Fibroblasts probably play an important role in PNI. Novelty & Impact Statements  The study is a thorough analysis of PNI in HNSCC from the clinical level to the molecular level and presents the first description of cancer-related PNI from the omics perspective to date as far as we know. We verified that PNI in HNSCC is a process of invasion rather than simple diffusion, at the molecular and omic levels. Fibroblasts were found to probably play an important role in PNI by analyzing single-cell transcriptomic data.

Different but synergistic effects of bone marrow-derived VEGFR2+ and VEGFR2-CD45+ cells during hepatocellular carcinoma progression.

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-associated mortality worldwide in men. Bone marrow-derived cells (BMDCs), including circulating endothelial progenitor cells, have been reported to be involved in the progression of HCC. The complexity of BMDCs inspires further interest in the study of HCC. In the present study, highly metastatic HCC models with BM function deficiency/reconstruction were established by sublethal irradiation/BM transplantation. The effects of vascular endothelial growth factor receptor-2 (VEGFR2)+ or VEGFR2-/cluster of differentiation 45 (CD45)+ BMDCs on HCC growth were evaluated. VEGFR2+ and VEGFR2-CD45+ BMDCs facilitated the recovery of BM function and promoted tumor growth, while the enhancement of tumor growth by VEGFR2-CD45+ BMDCs was independent of VEGFR2+ BMDCs. BM-derived CD45+CD133+ and VEGFR2+CD133+ cells synergistically played a role in the different stages during HCC progression. In conclusion, different types of BMDCs exhibit effects on HCC tumor growth in a coordinated manner.

Acetyl-CoA carboxylase rewires cancer metabolism to allow cancer cells to survive inhibition of the Warburg effect by cetuximab.

Cetuximab inhibits HIF-1-regulated glycolysis in cancer cells, thereby reversing the Warburg effect and leading to inhibition of cancer cell metabolism. AMP-activated protein kinase (AMPK) is activated after cetuximab treatment, and a sustained AMPK activity is a mechanism contributing to cetuximab resistance. Here, we investigated how acetyl-CoA carboxylase (ACC), a downstream target of AMPK, rewires cancer metabolism in response to cetuximab treatment. We found that introduction of experimental ACC mutants lacking the AMPK phosphorylation sites (ACC1_S79A and ACC2_S212A) into head and neck squamous cell carcinoma (HNSCC) cells protected HNSCC cells from cetuximab-induced growth inhibition. HNSCC cells with acquired cetuximab resistance contained not only high levels of T172-phosphorylated AMPK and S79-phosphorylated ACC1 but also an increased level of total ACC. These findings were corroborated in tumor specimens of HNSCC patients treated with cetuximab. Cetuximab plus TOFA (an allosteric inhibitor of ACC) achieved remarkable growth inhibition of cetuximab-resistant HNSCC xenografts. Our data suggest a novel paradigm in which cetuximab-mediated activation of AMPK and subsequent phosphorylation and inhibition of ACC is followed by a compensatory increase in total ACC, which rewires cancer metabolism from glycolysis-dependent to lipogenesis-dependent.

Prediction of survival prognosis of non-small cell lung cancer by APE1 through regulation of Epithelial-Mesenchymal Transition.

The DNA base excision repair gene APE1 involves in DNA damage repair pathway and overexpression in a variety of human cancers. Analyses of patients with non-small cell lung cancer (NSCLC) suggested that multiple factors associated with prognosis of NSCLC patients. Further investigation showed that APE1 expression was able to predict the progression-free survival and overall survival in patients with NSCLC and correlated with lymph node metastasis. Intriguingly, as a stratification of APE1-141 SNPs in APE1 positive expression, we also found APE1-141 GT/GG was identified as a marker for prediction of poor survival in NSCLC patients. In the in vitro experiments, the results showed that when APE1 expression was inhibited by siRNA or AT101 (an APE1 inhibitor), the migration and invasion of NSCLC cells were suppressed. Furthermore, Epithelial-Mesenchymal Transition (EMT) markers was tested to provide evidence that APE1 promoted NSCLC EMT through interaction with SirT1. Using NSCLC xenograft models, we confirmed that AT101 shrank tumor volumes and inhibited lymph node metastasis. In conclusion, APE1 could be a potential target for patients with NSCLC metastasis and AT101 is a potent inhibitor in further treatment of NSCLC patients.

AMPK-mediated energy homeostasis and associated metabolic effects on cancer cell response and resistance to cetuximab.

We previously reported that cetuximab, an EGFR-blocking antibody, inhibits cancer metabolism via downregulation of HIF-1α and reverses the Warburg effect in cancer cells. Here, we report that inhibition of HIF-1 transcriptional activity by cetuximab does not necessarily lead to successful inhibition of cell proliferation. In several head and neck squamous cell carcinoma (HNSCC) cell lines, we observed a pattern of oscillating decrease and increase of intracellular ATP level after cetuximab treatment, and the magnitude and kinetics of which varied by cell line and appeared to be linked to the extent of cellular response to cetuximab. In HNSCC cells with low basal level of AMPK activity and that responded to cetuximab-induced growth inhibition, there was a transient, LKB1-dependent activation of AMPK. In contrast, HNSCC cells that had a high basal level of AMPK activity were less sensitive to cetuximab-induced growth inhibition despite effective inhibition of EGFR downstream signaling by cetuximab. Knockdown or inhibition of AMPK markedly enhanced response to cetuximab via induction of apoptosis. These findings indicate that a transient activation of AMPK is an early metabolic marker of cellular response to cetuximab and that high and sustained AMPK activity is an important mechanism by which cancer cells survive cetuximab treatment.