A novel pVHL-independent but NEMO-driven pathway in renal cancer promotes HIF stabilization

Linear Ubiquitination Mediates EGFR-Induced NF-κB Pathway and Tumor Development

Epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase that instigates several signaling cascades, including the NF-κB signaling pathway, to induce cell differentiation and proliferation. Overexpression and mutations of EGFR are found in up to 30% of solid tumors and correlate with a poor prognosis. Although it is known that EGFR-mediated NF-κB activation is involved in tumor development, the signaling axis is not well elucidated. Here, we found that plakophilin 2 (PKP2) and the linear ubiquitin chain assembly complex (LUBAC) were required for EGFR-mediated NF-κB activation. Upon EGF stimulation, EGFR recruited PKP2 to the plasma membrane, and PKP2 bridged HOIP, the catalytic E3 ubiquitin ligase in the LUBAC, to the EGFR complex. The recruitment activated the LUBAC complex and the linear ubiquitination of NEMO, leading to IκB phosphorylation and subsequent NF-κB activation. Furthermore, EGF-induced linear ubiquitination was critical for tumor cell proliferation and tumor development. Knockout of HOIP impaired EGF-induced NF-κB activity and reduced cell proliferation. HOIP knockout also abrogated the growth of A431 epidermal xenograft tumors in nude mice by more than 70%. More importantly, the HOIP inhibitor, HOIPIN-8, inhibited EGFR-mediated NF-κB activation and cell proliferation of A431, MCF-7, and MDA-MB-231 cancer cells. Overall, our study reveals a novel linear ubiquitination signaling axis of EGFR and that perturbation of HOIP E3 ubiquitin ligase activity is potential targeted cancer therapy.

Identification of a Prognostic Risk Signature of Kidney Renal Clear Cell Carcinoma Based on Regulating the Immune Response Pathway Exploration

Purpose

To construct a survival model for predicting the prognosis of patients with kidney renal clear cell carcinoma (KIRC) based on gene expression related to immune response regulation.

Materials and Methods

KIRC mRNA sequencing data and patient clinical data were downloaded from the TCGA database. The pathways and genes involved in the regulation of the immune response were identified from the GSEA database. A single factor Cox analysis was used to determine the association of mRNA in relation to patient prognosis (P < 0.05). The prognostic risk model was further established using the LASSO regression curve. The survival prognosis model was constructed, and the sensitivity and specificity of the model were evaluated using the ROC curve.

Results

Compared with normal kidney tissues, there were 28 dysregulated mRNA expressions in KIRC tissues (P < 0.05). Univariate Cox regression analysis revealed that 12 mRNAs were related to the prognosis of patients with renal cell carcinoma. The LASSO regression curve drew a risk signature consisting of six genes: TRAF6, FYN, IKBKG, LAT2, C2, IL4, EREG, TRAF2, and IL12A. The five-year ROC area analysis (AUC) showed that the model has good sensitivity and specificity (AUC >0.712).

Conclusion

We constructed a risk prediction model based on the regulated immune response-related genes, which can effectively predict the survival of patients with KIRC.

Granular necrosis: a distinctive form of cell death in malignant tumours

Foci of necrosis are frequently seen in malignant tumours and may be due to a variety of causes. Different types of necrosis are given various names based upon their morphological features and presumed pathogenesis, such as coagulative, liquefactive and fibrinoid necrosis. Here, we propose the term 'granular necrosis' (GN) for a specific form of tumour necrosis characterised by the presence of well-defined necrotic foci being sharply demarcated from adjacent viable tumour. A constant feature is loss of architecture resulting in an amorphous necrotic mass containing granular nuclear and cytoplasmic debris, without an associated neutrophilic infiltrate. There is usually extensive karyorrhexis, which in larger tumours is more prominent at the periphery. These foci are often microscopic but may range up to several millimetres or larger in size. This distinctive form of necrosis has been erroneously given a variety of names in the literature including coagulative necrosis and microscopic necrosis, which on the basis of the aforementioned gross and microscopic findings is inappropriate. It is apparent that this is a specific form of necrosis, hence the descriptive term 'granular necrosis' that differentiates this form of necrosis from other types. The presence of GN is recognised as occurring in a variety of tumour types, being commonly seen in renal cell carcinoma, where it has been shown to have independent prognostic significance. In some epithelial and stromal tumours of the uterus, the presence of GN also has prognostic significance and is a defining feature for the differentiation of uterine leiomyoma and leiomyosarcoma. The pathogenesis of GN is unresolved. It does not show the features of apoptosis and in recent studies has been shown to have some of the molecular changes associated with necroptosis.

Cell death-related molecules and biomarkers for renal cell carcinoma targeted therapy

Renal cell carcinoma (RCC) is not sensitive to conventional radio- and chemotherapies and is at least partially resistant to impairments in cell death-related signaling pathways. The hallmarks of RCC formation include diverse signaling pathways, such as maintenance of proliferation, cell death resistance, angiogenesis induction, immune destruction avoidance, and DNA repair. RCC diagnosed during the early stage has the possibility of cure with surgery. For metastatic RCC (mRCC), molecular targeted therapy, especially antiangiogenic therapy (e.g., tyrosine kinase inhibitors, TKIs, such as sunitinib), is one of the main partially effective therapeutics. Various forms of cell death that may be associated with the resistance to targeted therapy because of the crosstalk between targeted therapy and cell death resistance pathways were originally defined and differentiated into apoptosis, necroptosis, pyroptosis, ferroptosis and autophagic cell death based on cellular morphology. Particularly, as a new form of cell death, T cell-induced cell death by immune checkpoint inhibitors expands the treatment options beyond the current targeted therapy. Here, we provide an overview of cell death-related molecules and biomarkers for the progression, prognosis and treatment of mRCC by targeted therapy, with a focus on apoptosis and T cell-induced cell death, as well as other forms of cell death.

Cutaneous squamous cell carcinoma, thyroid cancer and Langerhans cell histiocytosis in a patient with X-linked recessive Mendelian susceptibility to mycobacterial diseases with a nuclear factor-κB essential modifier mutation

Nuclear factor (NF)-κB essential modifier (NEMO), also known as IκB kinase subunit-γ (IKKγ), is a pivotal molecule in the NF-κB signaling pathway. Mutations of NEMO cause incontinentia pigmenti and X-linked ectodermal dysplasia with immunodeficiency. Mendelian susceptibility to mycobacterial diseases (MSMD), which confers an almost selective predisposition to mycobacterial infection, is also caused by NEMO mutations. We herein report the first case of a patient with X-linked recessive (XR) MSMD who developed cutaneous squamous cell carcinoma, thyroid cancer and Langerhans cell histiocytosis. The relationship between NEMO mutation and oncogenesis is discussed.

NEMO Links Nuclear Factor-κB to Human Diseases

The nuclear factor (NF)-κB essential modulator (NEMO) is a key regulator in NF-κB-mediated signaling. By transmitting extracellular or intracellular signals, NEMO can control NF-κB-regulated genes. NEMO dysfunction is associated with inherited diseases such as incontinentia pigmenti (IP), ectodermal dysplasia, anhidrotic, with immunodeficiency (EDA-ID), and some cancers. We focus on molecular studies, human case reports, and mouse models emphasizing the significance of NEMO molecular interactions and modifications in health and diseases. This knowledge opens new opportunities to engineer suitable drugs that may putatively target precise NEMO functions attributable to various diseases, while leaving other functions intact, and eliminating cytotoxicity. Indeed, with the advent of novel gene editing tools such as clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas)9, treating some inherited diseases may in the long run, become a reality.

NF-κB Members Left Home: NF-κB-Independent Roles in Cancer

Nuclear factor-κB (NF-κB) has been long considered a master regulator of inflammation and immune responses. Additionally, aberrant NF-κB signaling has been linked with carcinogenesis in many types of cancer. In recent years, the study of NF-κB members in NF-κB unrelated pathways provided novel attractive targets for cancer therapy, specifically linked to particular pathologic responses. Here we review specific functions of IκB kinase complexes (IKKs) and IκBs, which have distinctly tumor promoting or suppressing activities in cancer. Understanding how these proteins are regulated in a tumor-related context will provide new opportunities for drug development.

A compendium of proteins that interact with HIF-1α

Hypoxia-inducible factor 1 (HIF-1) is the founding member of a family of transcription factors that function as master regulators of oxygen homeostasis. HIF-1 is composed of an O₂-regulated HIF-1α subunit and a constitutively expressed HIF-1β subunit. This review provides a compendium of proteins that interact with the HIF-1α subunit, many of which regulate HIF-1 activity in either an O₂-dependent or O₂-independent manner.