Levels of 4EBP1/eIF4E Activation in Renal Cell Carcinoma Could Differentially Predict Its Early and Late Recurrence

Tumor Necrosis Factor Receptor-2 Signals Clear-Cell Renal Carcinoma Proliferation via Phosphorylated 4E Binding Protein-1 and Mitochondrial Gene Translation

Clear-cell renal cell carcinoma (ccRCC), a tubular epithelial malignancy, secretes tumor necrosis factor (TNF), which signals ccRCC cells in an autocrine manner via two cell surface receptors, TNFR1 and TNFR2, to activate shared and distinct signaling pathways. Selective ligation of TNFR2 drives cell cycle entry of malignant cells via a signaling pathway involving epithelial tyrosine kinase, vascular endothelial cell growth factor receptor type 2, phosphatidylinositol-3-kinase, Akt, pSer727-Stat3, and mammalian target of rapamycin. In this study, phosphorylated 4E binding protein-1 (4EBP1) serine 65 (pSer65-4EBP1) was identified as a downstream target of this TNFR2 signaling pathway. pSer65-4EBP1 expression was significantly elevated relative to total 4EBP1 in ccRCC tissue compared with that in normal kidneys, with signal intensity increasing with malignant grade. Selective ligation of TNFR2 with the TNFR2-specific mutein increased pSer65-4EBP1 expression in organ cultures that co-localized with internalized TNFR2 in mitochondria and increased expression of mitochondrially encoded COX (cytochrome c oxidase subunit) Cox1, as well as nuclear-encoded Cox4/5b subunits. Pharmacologic inhibition of mammalian target of rapamycin reduced both TNFR2-specific mutein-mediated phosphorylation of 4EBP1 and cell cycle activation in tumor cells while increasing cell death. These results signify the importance of pSer65-4EBP1 in mediating TNFR2-driven cell-cycle entry in tumor cells in ccRCC and implicate a novel relationship between the TNFR2/pSer65-4EBP1/COX axis and mitochondrial function.

Tumoral EIF4EBP1 regulates the crosstalk between tumor-associated macrophages and tumor cells in MRTK

Malignant renal rhabdoid tumor (MRTK) is an aggressive and rare malignancy primarily affecting infants and young children. The intricate interactions within the Tumor Microenvironment (TME) are crucial in shaping MRTK's progression. This study elucidates the significance of tumor-associated macrophages(TAMs) within this milieu and their interplay with eukaryotic translation initiation factor 4E-binding protein 1 (EIF4EBP1) in tumor cells, collectively contributing to MRTK's malignant advancement. Through comprehensive analysis of clinical samples and the TARGET database, EIF4EBP1 emerges as a central macrophage-associated gene with robust prognostic implications. Elevated EIF4EBP1 expression correlates with poor prognosis and heightened infiltration of TAMs. Functional validation demonstrates that EIF4EBP1 knockdown in G401 cells significantly attenuates self-proliferation, migration, and invasion. Moreover, EIF4EBP1 regulates macrophage recruitment and M2 polarization through the ERK/P38 MAPK-MIF axis. Notably, M2 macrophages reciprocally foster the malignant behavior of MRTK tumor cells. This study unveils the pivotal role of EIF4EBP1 in propelling MRTK's malignant progression, unraveling a complex regulatory network involving EIF4EBP1 and TAMs. These findings underscore EIF4EBP1 as a promising biomarker and highlight its therapeutic potential in MRTK management.

Late recurrence of chromophobe renal cell carcinoma to unusual sites after 12 years of radical nephrectomy and radiotherapy: a rare case report from Syria

In 2020, renal cell carcinoma (RCC) had an incidence of 73 750 new cases. This cancer is well known for its ability to give early and late metastases to some usual and unusual sites. The term 'late recurrence' is widely used to indicate a period exceeding 10 years from curative nephrectomy. This not-understood behaviour is almost specific to RCC, and it happens in a range between 4.3 and 11% of cases of RCC.

Case Presentation

We report a case of a 67-year-old nonalcoholic smoker Syrian male presented with a 2-month painful mass located at the left upper posterolateral abdominal wall's region. He has had a history of left chromophobe cell RCC treated with radical nephrectomy with adjuvant radiotherapy for 12 years. In light of computed tomography's findings, a surgical biopsy was performed, and a pathological and immunohistochemical examination confirmed the diagnosis of chromophobe RCC.

Clinical Discussion

Malignant cells seeding the surgical cut path and staying dormant for 12 years is the best theory of many to explain our case.

Conclusion

We reported evidence for the potential of a relatively indolent histologic type of RCC (i.e. chromophobe cell carcinoma) to cause late recurrence after 12 years to a very rare site (i.e. abdominal wall's superficial muscles). Research should focus on addressing late recurrence to determine the best surveillance protocols; investigating malignant cells seeding during surgery to improve surgical oncology's outcomes; and studying late recurrence's genetics to boost our targeted therapy options.

Decreasing expression of Prohibitin-2 lowers the oncogenicity of renal cell carcinoma cells by suppressing eIF4E-mediated oncogene translation via MNK inhibition

Prohibitin-2 (PHB2) serves as a key signalling protein that is connected with diverse cellular functions. PHB2 overexpression frequently occurs in cancers and is closely related to tumorigenesis. So far, the connection between PHB2 and renal cell carcinoma (RCC) has not been discussed yet. The purpose of this study was to explore the expression and biological function of PHB2 in RCC and to uncover the underlying mechanisms. High level of PHB2 was found in RCC tissues, and this overexpression was linked to a worse overall survival rate for RCC patients. In RCC cell, the lowering of PHB2 generated tumour-inhibiting effects in RCC cells such as proliferation retardation, cell cycle arrest, suppression of the capacity for metastasis, and chemosensitivity enhancement. Mechanistically, PHB2 mediated the activation of eukaryotic initiation factor 4E (eIF4E) and the translation of oncogenic proteins via the regulation of MNK. The inhibition of MNK diminished the effects of PHB2 on eIF4E-medited oncogene translation. The overexpression of eIF4E reversed PHB2-reduction-evoked tumour-inhibiting effects. Moreover, RCC cells with decreasing PHB2 exhibited a weakened ability to form xenografts in vivo. In conclusion, these findings show that PHB2 is pivotal for RCC progression and suggest that inhibiting MNK/eIF4E by decreasing PHB2 is a potential pathway for the treatment of RCC.

Clinical Characteristics and Prognostic Factors of Early and Late Recurrence After Definitive Radiotherapy for Nasopharyngeal Carcinoma

We investigated the clinical characteristics, prognostic factors, and post-recurrence prognostic factors of early- and late-recurrence patients for nasopharyngeal carcinoma (NPC) after definitive intensity-modulated radiation therapy (IMRT). This was a single-center retrospective analysis of patients in China from January 2010 to December 2015. The prognostic factors for overall survival (OS) and post-recurrence OS of early- and late-recurrence patients were identified using univariate and multivariate Cox regression analyses. Of the 9,468 patients included, 409 (4.3%), 325 (3.4%), and 182(1.9%) developed purely local recurrence, purely regional recurrence, and locoregional recurrence during follow-up, respectively. In the purely local recurrence group, 192 patients (46.9%) developed early local recurrence (ETR), and 217 patients (53.1%) developed late local recurrence (LTR). Of the 192 ETR patients, multivariate Cox regression analysis revealed that age and gender were independent risk factors of OS, and post-recurrence best supportive treatment (PRBST) was associated with poorer post-recurrence OS. Of the 217 LTR patients, the results revealed that baseline value of EBV-DNA was an independent risk factor for OS, while PRBST was associated with poorer post-recurrence OS. In the purely regional recurrence group, 183 patients (56.3%) developed early regional recurrence (ENR), and 142 patients (43.7%) developed late regional recurrence (LNR). Of the 183 ENR patients, multivariate Cox regression analysis revealed that alcohol abuse and TNM stage were independent risk factors of OS, while alcohol drinkers and PRBST were associated with poorer post-recurrence OS. Of the 142 LNR patients, PRBST was associated with poorer post-recurrence OS. In the locoregional recurrence group, 87 patients (47.8%) developed early locoregional recurrence (ELR), and 95 patients (52.2%) developed late locoregional recurrence (LLR). Of the 87 ELR patients, multivariate Cox regression analysis revealed that N stage and TNM stage were independent risk factors of OS, and N2/3 stage and PRBST were associated with poorer post-recurrence OS. Of the 95 LLR patients, the results revealed that T stage was an independent risk factor for OS, while T3/4 stage and PRBST were associated with poorer post-recurrence OS. Patients with LTR/LNR/LLR demonstrate significantly better OS compared with patients with ETR/ENR/ELR, Nevertheless, post-recurrence OS between patients with ETR/ENR/ELR and LTR/LNR/LLR was not significantly different.

Integrative Radiogenomics Approach for Risk Assessment of Post-Operative Metastasis in Pathological T1 Renal Cell Carcinoma: A Pilot Retrospective Cohort Study

Despite the increasing incidence of pathological stage T1 renal cell carcinoma (pT1 RCC), postoperative distant metastases develop in many surgically treated patients, causing death in certain cases. Therefore, this study aimed to create a radiomics model using imaging features from multiphase computed tomography (CT) to more accurately predict the postoperative metastasis of pT1 RCC and further investigate the possible link between radiomics parameters and gene expression profiles generated by whole transcriptome sequencing (WTS). Four radiomic features, including the minimum value of a histogram feature from inner regions of interest (ROIs) (INNER_Min_hist), the histogram of the energy feature from outer ROIs (OUTER_Energy_Hist), the maximum probability of gray-level co-occurrence matrix (GLCM) feature from inner ROIs (INNER_MaxProb_GLCM), and the ratio of voxels under 80 Hounsfield units (Hus) in the nephrographic phase of postcontrast CT (Under80HURatio), were detected to predict the postsurgical metastasis of patients with pathological stage T1 RCC, and the clinical outcomes of patients could be successfully stratified based on their radiomic risk scores. Furthermore, we identified heterogenous-trait-associated gene signatures correlated with these four radiomic features, which captured clinically relevant molecular pathways, tumor immune microenvironment, and potential treatment strategies. Our results of accurate surrogates using radiogenomics could lead to additional benefit from adjuvant therapy or postsurgical metastases in pT1 RCC.

mTOR: Role in cancer, metastasis and drug resistance

Mammalian target of rapamycin (mTOR) is a serine/threonine kinase that gets inputs from the amino acids, nutrients, growth factor, and environmental cues to regulate varieties of fundamental cellular processes which include protein synthesis, growth, metabolism, aging, regeneration, autophagy, etc. The mTOR is frequently deregulated in human cancer and activating somatic mutations of mTOR were recently identified in several types of human cancer and hence mTOR is therapeutically targeted. mTOR inhibitors were commonly used as immunosuppressors and currently, it is approved for the treatment of human malignancies. This review briefly focuses on the structure and biological functions of mTOR. It extensively discusses the genetic deregulation of mTOR including amplifications and somatic mutations, mTOR-mediated cell growth promoting signaling, therapeutic targeting of mTOR and the mechanisms of resistance, the role of mTOR in precision medicine and other recent advances in further understanding the role of mTOR in cancer.

Impact of eIF4E phosphorylation at Ser209 via MNK2a on tumour recurrence after curative surgery in localized clear cell renal cell carcinoma

Background: We investigated the roles of eIF4E phosphorylation (Ser209) in tumour recurrence after curative nephrectomy for localized clear cell renal cell carcinoma (ccRCC).

Methods: Expression of eIF4E, p eIF4E and MNKs (MAPK interacting kinases), was evaluated in surgical specimens obtained from consecutive non metastatic ccRCC patients (n = 290) by immunohistochemistry (IHC), immunoblotting, and qRT PCR at the protein and mRNA levels. In human RCC cell lines, the effects of eIF4E phosphorylation were examined using immunoblotting, proliferation, migration and invasion assays with pharmacological inhibitors (CGP57380 or ETP45835) and specific small interfering (si) RNAs against MNK1/2(a/b).

Results: In postoperative follow-up (median, 7.9 y), 40 patients experienced metastatic recurrence. In multivariate Cox analyses, higher IHC expression of p eIF4E in ccRCC significantly predicted a longer recurrence-free interval. eIF4E is phosphorylated mainly by MNK2a in tumour specimens and cell lines. In 786-O and A-498 cell lines, pharmacological inhibition of MNKs decreased p-eIF4E and increased vimentin and N cadherin but did not influence proliferation. Similarly, MNK2 or MNK2a inhibition with siRNA reduced p-eIF4E and enhanced vimentin translation, cell migration and invasion in the cell lines.

Conclusions: MNK2a-induced eIF4E phosphorylation may suppress metastatic recurrence of ccRCC, partially due to vimentin downregulation at the translational level, consequently leading to inhibition of epithelial–mesenchymal transition.

Expression of total and phospho 4EBP1 in metastatic and non-metastatic renal cell carcinoma

Eukaryotic translation initiation factor 4E-binding protein 1 (4EBP1) is phosphorylated and activated by mammalian target of rapamycin complex 1, which serves as a regulator of cell growth, cell survival, metastasis and angiogenesis in many types of cancer. The aim of this study was to evaluate the role of phosphorylated 4EBP1 (p4EBP1) in primary renal cell carcinoma (RCC) as a biomarker in metastatic RCC (mRCC) and non-mRCC cohorts. Primary tumor tissue from 254 non-mRCC and 60 mRCC patients were immunohistochemically stained for t4EBP1 and p4EBP1. The disease-free interval (DFI) categorized by the expressions and clinical parameters were assessed by univariate and multivariate analysis in the non-mRCC cohort. Then, the cause-specific survival (CSS) was assessed in the mRCC cohort by the same methods as used in the non-mRCC cohort. In the non-mRCC cohort, patients with t4EBP1 expression had no RCC recurrence. Patients with p4EBP1 expression had the shorter DFI in univariate analysis (P=0.037). p4EBP1 and pT1b-4 expression levels were independent predictors for de novo metastasis. In the mRCC cohort, intermediate/poor MSKCC risk, non-clear cell RCC, and no p4EBP1 expression were correlated with poor CSS on multivariate analysis. Expression of p4EBP1 could be a predictive biomarker for de novo metastasis in non-mRCC patient cohort. By contrast, mRCC patients showing no p4EBP1 expression had shorter CSS than patients with p4EBP1 expression.