Clinicopathological and prognostic significance of mTOR and phosphorylated mTOR expression in patients with esophageal squamous cell carcinoma: a systematic review and meta-analysis

PHF5A promotes esophageal squamous cell carcinoma progression via stabilizing VEGFA

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is the main subtype of esophageal cancer. Current therapeutic effect is far from satisfaction. Hence, identifying susceptible genes and potential targets is necessary for therapy of ESCC patients.

METHODS

Plant homeodomain (PHD)-finger domain protein 5 A (PHF5A) expression in ESCC tissues was examined by immunohistochemistry. RNA interference was used for in vitro loss-of-function experiments. In vivo assay was performed using xenograft mice model by subcutaneous injection. Besides, microarray assay and co-immunoprecipitation experiments were used to study the potential downstream molecules of PHF5A in ESCC. The molecular mechanism between PHF5A and vascular endothelial growth factor A (VEGFA) was explored by a series of ubiquitination related assays.

RESULTS

We found that PHF5A was highly expressed in ESCC tissues compared to normal tissues and that was correlated with poor prognosis of ESCC. Loss-of-function experiments revealed that PHF5A silence remarkably inhibited cell proliferation, migration, and induced apoptosis as well as cell cycle arrest. Consistently, in vivo assay demonstrated that PHF5A deficiency was able to attenuate tumor growth. Furthermore, molecular studies showed that PHF5A silencing promoted VEGFA ubiquitination by interacting with MDM2, thereby regulating VEGFA protein expression. Subsequently, in rescue experiments, our data suggested that ESCC cell viability and migration promoted by PHF5A were dependent on intact VEGFA. Finally, PI3K/AKT signaling rescue was able to alleviate shPHF5A-mediated cell apoptosis and cell cycle arrest.

CONCLUSION

PHF5A is a tumor promoter in ESCC, which is dependent on VEGFA and PI3K/AKT signaling. PHF5A might serve as a potential therapeutic target for ESCC treatment.

The clinicopathological and prognostic significance of mTOR and p-mTOR expression in patients with non-small cell lung cancer: A meta-analysis

BACKGROUND

The mammalian target of rapamycin (mTOR) has a crucial role in carcinogenesis, angiogenesis, cellular proliferation, and metastasis; however, its significance in non-small cell lung cancer (NSCLC) remains contentious. Consequently, this study aims to assess the clinicopathological and prognostic importance of mTOR/p-mTOR expression in NSCLC.

METHODS

Literature retrieval was undertaken by searching English databases PubMed, EMBASE, Web of Science, and Cochrane Library as well as Chinese databases CNKI, Wan Fang, and VIP for full-text publications that satisfied our eligibility criteria up to November 2021. STATA 12.0 was used to conduct statistical analysis (STATA Corporation, College Station, TX).

RESULTS

This meta-analysis includes a total of 4683 patients from 28 primary publications. mTOR/p-mTOR expression was associated with sex (OR = 0.608, 95% CI: 0.442-0.836), lymph node metastasis (OR = 2.084, 95% CI: 1.437-3.182), and CEA (OR = 1.584, 95% CI: 1.135-2.209), but not with age, histological type, depth of tumor invasion, distant metastasis, TNM stage, differentiation degree, tumor size, or smoking. In addition, the expression of mTOR/p-mTOR is related to shorter overall survival in NSCLC patients (HR = 1.415, 95% CI: 1.051-1.905).

CONCLUSION

Positive mTOR/p-mTOR expression was substantially correlated with unfavorable conditions on the sex, lymph node metastases, and CEA levels. mTOR/p-mTOR may indicate a bad prognosis for NSCLC. The current findings must be confirmed and changed by other high-quality research employing a multivariate analysis on bigger sample size.

Overexpression of GNA13 correlates with poor prognosis in esophageal squamous cell carcinoma after esophagectomy

BACKGROUND

This study aimed to explore the expression and clinical implication of guanine nucleotide-binding protein alpha 13 (GNA13) in esophageal squamous cell carcinoma (ESCC).

METHODS

We first employed western blot analysis to test the GNA13 protein expression level in ESCC tissues. Subsequently, we used immunohistochemistry assays to detect the GNA13 in ESCC specimens from 173 patients who underwent esophagectomy. Survival analysis was performed to define the impact of GNA13 expressions on the prognosis of the ESCC patients based on the clinical and follow-up data.

RESULTS

The GNA13 protein was shown to be considerably higher in ESCC tissues than in normal esophageal tissues. The level of expression was closely related to the tumor, node, TNM stage, and tumor size. More importantly, ESCC patients with high GNA13 expression carried an increased risk of tumor recurrence compared to those with low GNA13 expression. In addition, a high GNA13 expression level could independently predict worse overall survival and disease-free survival in ESCC.

CONCLUSIONS

GNA13 could be a novel prognostic biomarker for ESCC patients after esophagectomy.

Ethyl Ferulate Suppresses Esophageal Squamous Cell Carcinoma Tumor Growth Through Inhibiting the mTOR Signaling Pathway

Ethyl ferulate is a phenylpropanoid compound isolated from the medicinal herb Ferula. Although ethyl ferulate has anti-inflammatory, antioxidant, and neuroprotective activities with potential use in the nutraceutical and pharmaceutical industry, its anticancer effects and underlying molecular mechanisms against esophageal squamous cell carcinoma (ESCC) have not been investigated. This study investigates the anticancer activity and molecular mechanism of ethyl ferulate in ESCC. MTT, focus formation, soft agar, and cell cycle analysis were used to determine the effect of ethyl ferulate on cell proliferation and cell cycle. Potential candidate proteins were screened and verified via Western blotting, in vitro kinase assay, and in vitro pull-down assay. Mammalian target of rapamycin (mTOR) knockdown cell lines were established by lentiviral infection with shmTOR. The effect of ethyl ferulate on tumor growth was assessed using ESCC patient-derived xenograft models. Ethyl ferulate significantly inhibited cell growth and induced G1 phase cell cycle arrest in ESCC cells. Ethyl ferulate reduced the activity of mTOR in vitro. The inhibition of ESCC cell growth by ethyl ferulate is dependent on mTOR expression. In addition, ethyl ferulate strongly reduced ESCC patient-derived xenograft tumor growth in an in vivo mouse model. Ethyl ferulate is an mTOR inhibitor that can suppress ESCC progression and may be a novel candidate compound for esophageal cancer chemoprevention.

Comparison of efficacy and safety between pembrolizumab combined with chemotherapy and simple chemotherapy in neoadjuvant therapy for esophageal squamous cell carcinoma

BACKGROUND

Immunotherapy can activate the recognition of tumor antigen, build immune memory, and more and more clinical trials have taken the scheme of immunochemotherapy or immunoradiotherapy as a treatment strategy for esophageal squamous cell carcinoma (ESCC). Our objective was to compare the efficacy and safety between pembrolizumab combined with the chemotherapy group and simple chemotherapy in neoadjuvant therapy of ESCC.

METHODS

Fifty-four ESCC patients with stage II-IVa were enrolled at the Fifth Affiliated Hospital of Sun Yat-sen University between January 2018 and December 2020, including 23 in the pembrolizumab combined with chemotherapy group (combined group), and 31 in the simple chemotherapy group. All patients received radical surgical treatment after two cycles of neoadjuvant therapy.

RESULTS

The pathological complete response (pCR) and objective response rate (ORR) in the combined group were significantly higher than that of the simple chemotherapy group (30.4% vs. 9.7%, P=0.048; 86.9% vs. 95.7%, P=0.017) as well as the score of tumor regression ≥2 (80.7% vs. 50.0%, P=0.013). And the complete rate of esophagectomy and R0 /R1 resection rate in the two groups were not statistically significant. Otherwise, the incidence of adverse events in the combined group was similar compared with the simple chemotherapy group.

CONCLUSIONS

Pembrolizumab combined with chemotherapy showed promising activity with a manageable safety profile. And it could offer a potential new neoadjuvant treatment approach for patients with ESCC.

Assessment of PI3K/mTOR/AKT Pathway Elements to Serve as Biomarkers and Therapeutic Targets in Penile Cancer

The PI3K/mTOR/AKT pathway might represent an intriguing option for treatment of penile cancer (PeCa). We aimed to assess whether members of this pathway might serve as biomarkers and targets for systemic therapy. Tissue of primary cancer from treatment-naïve PeCa patients was used for tissue microarray analysis. Immunohistochemical staining was performed with antibodies against AKT, pAKT, mTOR, pmTOR, pS6, pPRAS, p4EBP1, S6K1 and pp70S6K. Protein expression was correlated with clinicopathological characteristics as well as overall survival (OS), disease-specific survival (DSS), recurrence-free survival (RFS) and metastasis-free survival (MFS). AKT inhibition was tested in two primarily established, treatment-naïve PeCa cell lines by treatment with capivasertib and analysis of cell viability and chemotaxis. A total of 76 patients surgically treated for invasive PeCa were included. Higher expression of AKT was significantly more prevalent in high-grade tumors and predictive of DSS and OS in the Kaplan-Meier analysis, and an independent predictor of worse OS and DSS in the multivariate regression analysis. Treatment with pan-AKT inhibitor capivasertib in PeCa cell lines induced a significant downregulation of both total AKT and pAKT as well as decreased cell viability and chemotaxis. Selected protein candidates of the mTOR/AKT signaling pathway demonstrate association with histological and survival parameters of PeCa patients, whereas AKT appears to be the most promising one.

Knockdown of GTF2E2 inhibits the growth and progression of lung adenocarcinoma via RPS4X in vitro and in vivo

Background

Lung adenocarcinoma (LUAD) is one of the most common malignancies worldwide. However, the molecular mechanism of LUAD tumorigenesis and development remains unclear. The purpose of this study was to comprehensively illustrate the role of GTF2E2 in the growth and progression of LUAD.

Methods and materials

We obtained the mRNA expression data from The Cancer Genome Atlas, Gene Expression Omnibus database, and our institution. Systematic bioinformatical analyses were performed to investigate the expression and prognostic value of GTF2E2 in LUAD. The results were validated by immunohistochemistry and qPCR. The effect of knocking down GTF2E2 using two short hairpin RNAs was investigated by in vitro and in vivo assays. Subsequently, shotgun liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS) analyses were applied to identified potential GTF2E2 interacting proteins, and the downstream molecular mechanisms of GTF2E2-signaling were further explored by a series of cellular functional assays.

Results

We found that GTF2E2 expression was significantly increased in LUAD tissue compared with adjacent normal tissue and was negatively associated with patients’ overall survival. Besides, we demonstrated that GTF2E2 knockdown inhibited LUAD cell proliferation, migration, invasion, and promote apoptosis in vitro, as well as attenuated tumor growth in vivo. Results from LC–MS/MS suggested that RPS4X might physically interact with GTF2E2 and mediated GTF2E2’s regulatory effect on LUAD development through the mTOR pathway.

Conclusion

Our findings indicate that GTF2E2 promotes LUAD development by activating RPS4X. Therefore, GTF2E2 might serve as a promising biomarker for the diagnosis and prognosis of LUAD patients, thus shedding light on the precise and personalized therapy for LUAD in the future.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-01878-z.

The Role of mTOR Signaling as a Therapeutic Target in Cancer

The aim of this review was to summarize current available information about the role of phosphatidylinositol-3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling in cancer as a potential target for new therapy options. The mTOR and PI3K/AKT/mTORC1 (mTOR complex 1) signaling are critical for the regulation of many fundamental cell processes including protein synthesis, cell growth, metabolism, survival, catabolism, and autophagy, and deregulated mTOR signaling is implicated in cancer, metabolic dysregulation, and the aging process. In this review, we summarize the information about the structure and function of the mTOR pathway and discuss the mechanisms of its deregulation in human cancers including genetic alterations of PI3K/AKT/mTOR pathway components. We also present recent data regarding the PI3K/AKT/mTOR inhibitors in clinical studies and the treatment of cancer, as well the attendant problems of resistance and adverse effects.

Development of chemotherapeutics for unresectable advanced esophageal cancer

INTRODUCTION

The prognosis of unresectable advanced esophageal squamous cell carcinoma (ESCC) has gradually improved due to efforts for the development of systemic chemotherapy or concurrent chemoradiotherapy.

AREAS COVERED

Chemotherapeutic agents such as cytotoxic agents, molecular-targeted agents, and immune checkpoint inhibitors, sometimes used with irradiation, lead in the treatment of unresectable advanced ESCC. Here, we review the latest treatment strategies for unresectable advanced ESCC and discuss future perspectives.

EXPERT OPINION

Immunotherapeutic agents will be part of the treatment of unresectable advanced ESCC in the near future. However, definitive predictive biomarkers to determine good patient candidates remain unclear for immunotherapy in patients with ESCC. Further research is warranted to identify those biomarkers working individually and in combination. Moreover, genome-based therapeutics enable individualized and patient-specific treatment. The development of molecular-targeted drugs against actionable or druggable genes is in progress.

Prognostic role of aberrant mTOR activation in patients with stage II and III colorectal cancer

Aim: This study aimed to develop an effective risk predictor for patients with stage II and III colorectal cancer (CRC). Materials & methods: The prognostic value of p-mTOR (Ser2448) levels was analyzed using Kaplan-Meier survival analysis and Cox regression analysis. Results: The levels of p-mTOR were increased in CRC specimens and significantly correlated with poor prognosis in patients with stage II and III CRC. Notably, the p-mTOR level was an independent poor prognostic factor for disease-free survival and overall survival in stage II CRC. Conclusion: Aberrant mTOR activation was significantly associated with the risk of recurrence or death in patients with stage II and III CRC, thus this activated proteins that may serve as a potential biomarker for high-risk CRC.

Metabolic Fitness and Plasticity in Cancer Progression

Cancer cells have enhanced metabolic needs due to their rapid proliferation. Moreover, throughout their progression from tumor precursors to metastases, cancer cells face challenging physiological conditions, including hypoxia, low nutrient availability, and exposure to therapeutic drugs. The ability of cancer cells to tailor their metabolic activities to support their energy demand and biosynthetic needs throughout disease progression is key for their survival. Here, we review the metabolic adaptations of cancer cells, from primary tumors to therapy resistant cancers, and the mechanisms underpinning their metabolic plasticity. We also discuss the metabolic coupling that can develop between tumors and the tumor microenvironment. Finally, we consider potential metabolic interventions that could be used in combination with standard therapeutic approaches to improve clinical outcome.

Intratumoral Heterogeneity Determines the Expression of mTOR-pathway Proteins in Prostate Cancer

The aim of this study was to evaluate the expression of mammalian target of rapamycin (mTOR), phosphorylated-mTOR (p-mTOR), and eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) in prostate cancer (PCa) in order to assess intratumoral heterogeneity and correlation with clinicopathological parameters. Tissue samples from 115 patients undergoing radical prostatectomy were included in a tissue microarray comprising (A) tissue from the tumor center, (B) malignant border of the tumor, (C) tumor-adjacent benign tissue, and (D) tumor-distant benign prostatic tissue. Immune reactive scores 0-12 were correlated with clinical data in reference to localization. A meta-analysis of studies investigating the association between biochemical recurrence (BCR) and parameters of the mTOR pathway was conducted. Regardless of the location within the tumor, cancer tissue showed higher expression of mTOR, p-mTOR, and 4EB-P1 compared to benign tissue (p < 0.01). Significant differences in expression between tissue samples from groups C and D were observed for mTOR and p-mTOR. When considering expression according to the pathological stage, we observed lower p-mTOR expression in pT3 vs. pT2 (7.9 and 6.3; p = 0.01). After a median follow-up of 74.5 months (IQR 65.0-84.0), 27 patients (23.47%) developed BCR. Weak staining of mTOR was associated with shorter time to BCR (HR: 2.0; p = 0.049) after correcting for PSA and T stage. However, a significant association of mTOR expression with BCR was found for specimens from the malignant border of the tumor (B) but not the tumor center (A) (p = 0.0034 log rank). In a meta-analysis, we found that the expressions of mTOR ((RR) = 0.70; 95% CI 0.43-1.12; p = 0.13) and 4E-BP1 ((RR) = 0.86; p = 0.53) were not statistically associated with BCR, while strong staining of p-mTOR was associated with a lower risk of BCR ((RR) = 0.57; p = 0.002). All 3 markers showed stronger expression in PCa and exhibited local gradients in relation to the border of tumor and healthy tissue. Our results suggest an important role of intratumor heterogeneity for the use of mTOR parameters as biomarkers in PCa.

Systemic treatment of advanced esophageal squamous cell carcinoma: chemotherapy, molecular-targeting therapy and immunotherapy

Systemic treatment of advanced esophageal squamous cell carcinoma (ESCC) mainly consists of cytotoxic agents, aiming to palliate symptoms and prolong survival. Cisplatin and 5-fluorouracil have been considered standard treatment for several decades. Efforts to develop more effective treatment have led to clinical trials testing triplet, irinotecan-based, oxaliplatin-based and paclitaxel-based regimens. Molecular-targeting agents, mainly anti-EGFR inhibitors including gefitinib, panitumumab and nimotuzumab, have been investigated; however, no molecular-targeting agents demonstrate the clinical utility in Phase 3 trials so far. Negative results from Phase 3 trials testing gefitinib and panitumumab suggest the importance of identifying predictive biomarkers of responses to molecular-targeting agents. On the basis of results from Phase 3 trials testing PD-1 inhibitors, nivolumab and pembrolizumab, are anticipated to be the standard treatment for patients with ESCC. Dual immune checkpoint inhibition and immunotherapy in combination with cytotoxic agents are under study. Recent advances in next-generation sequencing technologies provide comprehensive catalogues of genetic alterations in ESCC which may lead to therapeutic breakthroughs in a personalized manner. Here, we review the existing clinical data and discuss future perspectives with a focus on the systemic treatment of advanced ESCC.

hsa_circ_0006168 sponges miR-100 and regulates mTOR to promote the proliferation, migration and invasion of esophageal squamous cell carcinoma

Circle RNAs (circRNAs) are the novel noncoding RNAs with the covalent closed-loop structure, which play a crucial role in a variety of pathological processes, including cancer. Nevertheless, the expression profiles and functions of circRNAs in esophageal squamous cell cancer (ESCC) remain largely unknown. In this paper, 10 pairs of ESCC tissues were utilized to screen the circRNA expression profiles by means of microarray assay; further, a novel circular RNA named hsa_circ_0006168 was investigated. Meanwhile, the expression of hsa_circ_0006168 was measured in 52 ESCC tissues and in cell lines. Our results suggested that, hsa_circ_0006168 was remarkably increased not only in ESCC tissues but also in cell lines compared with those in normal cases. Besides, high hsa_circ_0006168 expression was positively connected with lymph node metastasis and TNM stage of ESCC patients. In vitro, the proliferation, invasion and migration capacities of ESCC cells were suppressed through down-regulating hsa_circ_0006168 expression. Besides, RNase R digestion assay confirmed that hsa_circ_0006168 was more stable than its linear CNOT6L mRNA form. Moreover, nuclear and cytoplasmic fraction assay indicated that hsa_circ_0006168 was mainly distributed in the cytoplasm of Kyse450 and TE13 cells. Mechanically, it was discovered in this study that hsa_circ_0006168 might regulate the expression of Mammalian Target of Rapamycin (mTOR) by sponging microRNA-100 (miR-100). Taken together, hsa_circ_0006168 can promote ESCC proliferation, migration and invasion through the competing endogenous RNA (ceRNA) mechanism, which has been first confirmed in our results. In ESCC, hsa_circ_0006168 can serve as a potential diagnostic biomarker and therapeutic target.

mTOR Signalling in Head and Neck Cancer: Heads Up

The mammalian target of rapamycin (mTOR) signalling pathway is a central regulator of metabolism in all cells. It senses intracellular and extracellular signals and nutrient levels, and coordinates the metabolic requirements for cell growth, survival, and proliferation. Genetic alterations that deregulate mTOR signalling lead to metabolic reprogramming, resulting in the development of several cancers including those of the head and neck. Gain-of-function mutations in EGFR, PIK3CA, and HRAS, or loss-of-function in p53 and PTEN are often associated with mTOR hyperactivation, whereas mutations identified from The Cancer Genome Atlas (TCGA) dataset that potentially lead to aberrant mTOR signalling are found in the EIF4G1, PLD1, RAC1, and SZT2 genes. In this review, we discuss how these mutant genes could affect mTOR signalling and highlight their impact on metabolic processes, as well as suggest potential targets for therapeutic intervention, primarily in head and neck cancer.

TRIM59 is a novel potential prognostic biomarker in patients with non-small cell lung cancer: A research based on bioinformatics analysis

Lung cancer is the leading cause of cancer-associated mortality worldwide and its prognosis is poor. Few effective biomarkers for non-small cell lung cancer (NSCLC) have been translated into the clinical practice aiming to assist in the treatment plan design and prognosis evaluation. The aim of the present study was to identify novel potential prognostic biomarkers for NSCLC. Tripartite motif 59 (TRIM59) was identified from a microarray dataset of matched-samples and was verified as an aberrantly upregulated gene in NSCLC tissue. The expression level of TRIM59 in NSCLC subtypes was observed to be significantly increased in large cell lung carcinoma and squamous cell carcinoma as compared with that in adenocarcinoma. Its expression correlated with several clinicopathological features, including gender, smoking habits, and unfavorable tumor node and pathological stages. Notably, TRIM59 demonstrated a negative correlation with survival time and its overexpression indicated a poor prognosis in NSCLC. Furthermore, univariate and multivariate Cox's regression analyses indicated that TRIM59 was an independent prognostic factor in tumor tissue as compared with age, gender, tumor stage, node stage, and metastasis. Gene set enrichment analysis and protein-protein interaction network construction revealed that TRIM59 was associated with oncogenic mammalian target of rapamycin (MTOR) and eukaryotic initiation factor 4E (EIF4E) signaling through ubiquitin C binding. In conclusion, it was revealed that TRIM59 is a novel prognostic biomarker modulating oncogenic MTOR and EIF4E signaling pathways in NSCLC. These findings provided a novel insight into the clinical application of TRIM59. Therefore, TRIM59 may serve as an independent predictor for prognosis and a potential therapeutic target for NSCLC.

Diabetes mellitus and risk of anastomotic leakage after esophagectomy: a systematic review and meta-analysis

Diabetes mellitus has the probability to impair the anastomotic healing and cause postesophagectomy anastomotic leakages but previous studies showed controversial results. This review aims to summary the impact of diabetes mellitus on the risk of anastomotic leakage after esophagectomy. We searched the PubMed and EMBASE databases to recognize English articles that met our eligibility criteria. Odds ratio with 95% confidence interval serves as the appropriate summarized statistic. Sensitivity analysis, meta-regression analysis, and publication bias tests were also performed to perceive potential bias risks. Finally, 16 observational studies with 12359 surgical patients were included. An overall analysis identified that diabetes mellitus was significantly associated with the risk of anastomotic leakage after esophagectomy (odds ratio = 1.63; 95% confidence interval = 1.25-2.12; P < 0.001). Further subgroup analysis showed a significant impact of diabetes mellitus in surgical populations from the Europe and America (odds ratio = 1.42; 95% confidence interval = 1.22-1.65; P < 0.001) but not in the Asian populations (odds ratio = 2.27; 95% confidence interval = 0.86-6.05; P = 0.1). The robustness of these estimates was confirmed by meta-regression analysis and sensitivity analysis. No significant publication bias exists between studies. In conclusion, this systematic review demonstrates that diabetes mellitus can be a significant risk factor of anastomotic leakage for patients undergoing esophagectomy. Our findings need to be further confirmed and modified by more well-designed worldwide multivariable analyses in the future.