Overexpression of HACE1 in gastric cancer inhibits tumor aggressiveness by impeding cell proliferation and migration

Unveiling the role of HACE1 in cervical cancer: implications for human papillomavirus infection and prognosis

Background

Cervical cancer, one of the prevalent malignancies among females, is closely associated with human papillomavirus (HPV) infection. Homologous to the E6-AP carboxyl terminus (HECT) domain and ankyrin repeat containing E3 ubiquitin-protein ligase 1 (HACE1) plays pivotal roles in various cancers. This study aimed to elucidate the expression of HACE1 in cervical cancer and its correlation with clinical features.

Methods

From The Cancer Genome Atlas Cervical Squamous Cell Carcinoma and Endocervical Adenocarcinoma (TCGA-CESC) and Gene Expression Omnibus (GEO, GSE6791) datasets, we obtained RNA-Seq profiles and associated clinical information. Differential gene analysis was conducted using the R "limma" package. Implications for HPV infection and the overall survival (OS) of cervical cancer were determined by performing differential expression analysis and the Cox proportional hazards regression model. Immunohistochemical analyses were used to validate the expression in cervical cancer and normal cervical tissue. Further, nomogram was constructed to predict OS in cervical cancer. Whether the model was credible was evaluated according to receiver operating characteristic (ROC) curves and concordance curves. To further evaluate the potential functions of HACE1, we conducted functional enrichment analysis. Finally, we assessed methylation levels in HPV+ and HPV- patients in the TCGA-CESC dataset.

Results

Utilizing TCGA and GSE6791 datasets, we observed significant upregulation of HACE1 in cervical cancer patients, particularly linked to HPV infection. Immunohistochemical staining revealed enhanced HACE1 expression in tumor tissues. Further analysis demonstrated a significant positive correlation between elevated HACE1 and HPV-associated proteins (E1, E6, and E7). Moreover, high HACE1 expression was associated with adverse prognosis in cervical cancer patients. Multivariate Cox analysis indicated that HACE1 could serve as an independent prognostic factor. We developed a prognostic model integrating HPV subtypes, the International Federation of Gynecology and Obstetrics (FIGO) staging, and HACE1, exhibiting strong predictive efficacy for cervical cancer prognosis. Gene enrichment analysis indicated HACE1's potential involvement in multiple signaling pathways during cervical cancer progression, while the demethylation of cg03002526 in HPV-positive patients might contribute to HACE1 upregulation.

Conclusions

Our study reveals that HACE1 upregulation is associated with cervical cancer, particularly in HPV-positive patients. HACE1 emerges as an independent prognostic factor, linked to unfavorable outcomes.

Inhibition of esophageal cancer progression through HACE1-TRIP12 interaction and associated RAC1 ubiquitination and degradation

Objective: This study investigated the significance of HECT domain and ankyrin repeat containing E3 ubiquitin protein ligase 1 (HACE1) in esophageal cancer (ESCA) and its underlying mechanism in ESCA regulation through the induction of RAC1 ubiquitination and degradation. Methods: Characterization studies of HACE1 in ESCA clinical tissues and cell lines were performed. Next, the effects of HACE1 on the biological behavior of ESCA cells were examined by silencing and overexpressing HACE1. Protein-protein interactions (PPIs) involving HACE1 were analyzed using data from the String website. The function of HACE1 in RAC1 protein ubiquitination was validated using the proteasome inhibitor MG132. The effects of HACE1 on ESCA cells through RAC1 were elucidated by applying the RAC1 inhibitor EHop-016 in a tumor-bearing nude mouse model. To establish the relationship between HACE1 and TRIP12, rescue experiments were conducted, mainly to evaluate the effect of TRIP12 silencing on HACE1-mediated RAC1 regulation in vitro and in vivo. The PPI between HACE1 and TRIP12 and their subcellular localization were further characterized through co-immunoprecipitation and immunofluorescence staining assays, respectively. Results: HACE1 protein expression was notably diminished in ESCA cells but upregulated in normal tissues. HACE1 overexpression inhibited the malignant biological behavior of ESCA cells, leading to restrained tumor growth in mice. This effect was coupled with the promotion of RAC1 protein ubiquitination and subsequent degradation. Conversely, silencing HACE1 exhibited contrasting results. PPI existed between HACE1 and TRIP12, compounded by their similar subcellular localization. Intriguingly, TRIP12 inhibition blocked HACE1-driven RAC1 ubiquitination and mitigated the inhibitory effects of HACE1 on ESCA cells, alleviating tumor growth in the tumor-bearing nude mouse model. Conclusion: HACE1 expression was downregulated in ESCA cells, suggesting that it curbs ESCA progression by inducing RAC1 protein degradation through TRIP12-mediated ubiquitination.

The HACE1 E3 ligase mediates RAC1-dependent control of mTOR signaling complexes

HACE1 is a HECT family E3 ubiquitin-protein ligase with broad but incompletely understood tumor suppressor activity. Here, we report a previously unrecognized link between HACE1 and signaling complexes containing mammalian target of rapamycin (mTOR). HACE1 blocks mTORC1 and mTORC2 activities by reducing mTOR stability in an E3 ligase-dependent manner. Mechanistically, HACE1 binds to and ubiquitylates Ras-related C3 botulinum toxin substrate 1 (RAC1) when RAC1 is associated with mTOR complexes, including at focal adhesions, leading to proteasomal degradation of RAC1. This in turn decreases the stability of mTOR to reduce mTORC1 and mTORC2 activity. HACE1 deficient cells show enhanced mTORC1/2 activity, which is reversed by chemical or genetic RAC1 inactivation but not in cells expressing the HACE1-insensitive mutant, RAC1K147R . In vivo, Rac1 deletion reverses enhanced mTOR expression in KRasG12D -driven lung tumors of Hace1-/- mice. HACE1 co-localizes with mTOR and RAC1, resulting in RAC1-dependent loss of mTOR protein stability. Together, our data demonstrate that HACE1 destabilizes mTOR by targeting RAC1 within mTOR-associated complexes, revealing a unique ubiquitin-dependent process to control the activity of mTOR signaling complexes.

UPS: Opportunities and challenges for gastric cancer treatment

Gastric cancer remains the fourth most frequently diagnosed malignancy and the fifth leading cause of cancer-related mortality worldwide owning to the lack of efficient drugs and targets for therapy. Accumulating evidence indicates that UPS, which consists of E1, E2, and E3 enzymes and proteasome, plays an important role in the GC tumorigenesis. The imbalance of UPS impairs the protein homeostasis network during development of GC. Therefore, modulating these enzymes and proteasome may be a promising strategy for GC target therapy. Besides, PROTAC, a strategy using UPS to degrade the target protein, is an emerging tool for drug development. Thus far, more and more PROTAC drugs enter clinical trials for cancer therapy. Here, we will analyze the abnormal expression enzymes in UPS and summarize the E3 enzymes which can be developed in PROTAC so that it can contribute to the development of UPS modulator and PROTAC technology for GC therapy.

Emerging roles of the HECT E3 ubiquitin ligases in gastric cancer

Gastric cancer (GC) is one of the most pernicious gastrointestinal tumors with extraordinarily high incidence and mortality. Ubiquitination modification of cellular signaling proteins has been shown to play important roles in GC tumorigenesis, progression, and prognosis. The E3 ubiquitin ligase is the crucial enzyme in the ubiquitination reaction and determines the specificity of ubiquitination substrates, and thus, the cellular effects. The HECT E3 ligases are the second largest E3 ubiquitin ligase family characterized by containing a HECT domain that has E3 ubiquitin ligase activity. The HECT E3 ubiquitin ligases have been found to engage in GC progression. However, whether HECT E3 ligases function as tumor promoters or tumor suppressors in GC remains controversial. In this review, we will focus on recent discoveries about the role of the HECT E3 ubiquitin ligases, especially members of the NEDD4 and other HECT E3 ligase subfamilies, in GC.

Cyclin C: A new responser for chemosensitivity in cancer

The resistance to cisplatin‐based chemotherapy is a common cause of poor prognosis in cancer patients. Cisplatin stimulation causes cyclin C translocating to mitochondria, and in turn induces mitochondrial fission. However, little is known about the role of cyclin C in mitochondrial dysfunction in cancer cells challenged with cisplatin. In the present commentary, we bring to the attention of readers the recent report by Jiang et al which revealed the importance of ubiquitylation and translocation of cyclin C in gastric cancer cells in response to cisplatin stimulation for mitochondrial stability. This finding provides new insights into exploring the novel mechanisms of chemoresistance and developing the new chemotherapy synergistic agents in the era of precision oncology.

Ubiquitylation of cyclin C by HACE1 regulates cisplatin-associated sensitivity in gastric cancer

BACKGROUND

Cyclin C (CCNC) was reported to take part in regulating mitochondria-derived oxidative stress under cisplatin stimulation. However, its effect in gastric cancer is unknown. This study aimed to investigate the role of cyclin C and its ubiquitylation in regulating cisplatin resistance in gastric cancer.

METHODS

The interaction between HECT domain and ankyrin repeat-containing E3 ubiquitin-protein ligase 1 (HACE1) and cyclin C was investigated by GST pull-down assay, co-immunoprecipitation and ubiquitylation assay. Mitochondria-derived oxidative stress was studied by MitoSOX Red assay, seahorse assay and mitochondrial membrane potential measurement. Cyclin C-associated cisplatin resistance was studied in vivo via xenograft.

RESULTS

HACE1 catalysed the ubiquitylation of cyclin C by adding Lys11-linked ubiquitin chains when cyclin C translocates to cytoplasm induced by cisplatin treatment. The ubiquitin-modified cyclin C then anchor at mitochondira, which induced mitochondrial fission and ROS synthesis. Depleting CCNC or mutation on the ubiquitylation sites decreased mitochondrial ROS production and reduced cell apoptosis under cisplatin treatment. Xenograft study showed that disrupting cyclin C ubiquitylation by HACE1 conferred impairing cell apoptosis response upon cisplatin administration.

CONCLUSIONS

Cyclin C is a newly identified substrate of HACE1 E3 ligase. HACE1-mediated ubiquitylation of cyclin C sheds light on a better understanding of cisplatin-associated resistance in gastric cancer patients. Ubiquitylation of cyclin C by HACE1 regulates cisplatin-associated sensitivity in gastric cancer. With cisplatin-induced nuclear-mitochondrial translocation of cyclin C, its ubiquitylation by HACE1 increased mitochondrial fission and mitochondrial-derived oxidative stress, leading to cell apoptosis.

A novel tumor doubling time-related immune gene signature for prognosis prediction in hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) has become a global health issue of wide concern due to its high prevalence and poor therapeutic efficacy. Both tumor doubling time (TDT) and immune status are closely related to the prognosis of HCC patients. However, the association between TDT-related genes (TDTRGs) and immune-related genes (IRGs) and the value of their combination in predicting the prognosis of HCC patients remains unclear. The current study aimed to discover reliable biomarkers for anticipating the future prognosis of HCC patients based on the relationship between TDTRGs and IRGs.

Methods

Tumor doubling time-related genes (TDTRGs) were acquired from GSE54236 by using Pearson correlation test and immune-related genes (IRGs) were available from ImmPort. Prognostic TDTRGs and IRGs in TCGA-LIHC dataset were determined to create a prognostic model by the LASSO-Cox regression and stepwise Cox regression analysis. International Cancer Genome Consortium (ICGC) and another cohort of individual clinical samples acted as external validations. Additionally, significant impacts of the signature on HCC immune microenvironment and reaction to immune checkpoint inhibitors were observed.

Results

Among the 68 overlapping genes identified as TDTRG and IRG, a total of 29 genes had significant prognostic relevance and were further selected by performing a LASSO-Cox regression model based on the minimum value of λ. Subsequently, a prognostic three-gene signature including HECT domain and ankyrin repeat containing E3 ubiquitin protein ligase 1 (HACE1), C-type lectin domain family 1 member B (CLEC1B), and Collectin sub-family member 12 (COLEC12) was finally identified by stepwise Cox proportional modeling. The signature exhibited superior accuracy in forecasting the survival outcomes of HCC patients in TCGA, ICGC and the independent clinical cohorts. Patients in high-risk subgroup had significantly increased levels of immune checkpoint molecules including PD-L1, CD276, CTLA4, CXCR4, IL1A, PD-L2, TGFB1, OX40 and CD137, and are therefore more sensitive to immune checkpoint inhibitors (ICIs) treatment. Finally, we first found that overexpression of CLEC1B inhibited the proliferation and migration ability of HuH7 cells.

Conclusions

In summary, the prognostic signature based on TDTRGs and IRGs could effectively help clinicians classify HCC patients for prognosis prediction and individualized immunotherapies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02227-w.

Knockdown of CENPK inhibits cell growth and facilitates apoptosis via PTEN-PI3K-AKT signalling pathway in gastric cancer

Previous studies have indicated that centromere protein K (CENPK) is upregulated in several cancers and related to tumorigenesis. Nevertheless, the potential function of CENPK in gastric cancer (GC) remains unknown. Here, we investigated the function of CENPK on oncogenicity and explored its underlying mechanisms in GC. Our results showed that CENPK was dramatically overexpressed in GC and was associated with poor prognosis through bioinformatics analysis. We demonstrated that CENPK is upregulated in GC tissues and cell lines. Moreover, knockdown of CENPK significantly inhibited proliferation in vitro and attenuated the growth of implanted GCs in vivo. In addition, CENPK silencing induced G1 phase cell cycle arrest and facilitated apoptosis of GC cells. KEGG pathway analysis indicated that the PI3K-AKT signalling pathway was considerably enriched. Knockdown of CENPK decreased the expression of PI3K, p-Akt (Ser437) and p-GSK3β (Ser9) in GC cells, and increased the expression of PTEN. In conclusion, this study indicated that CENPK was overexpressed in GC and may promote gastric carcinogenesis through the PTEN-PI3K-AKT signalling pathway. Thus, CENPK may be a potential target for cancer therapeutics in GC.

Manifold role of ubiquitin in Helicobacter pylori infection and gastric cancer

Infection with H. pylori induces a strong host cellular response represented by induction of a set of molecular signaling pathways, expression of proinflammatory cytokines and changes in proliferation. Chronic infection and inflammation accompanied by secretory dysfunction can result in the development of gastric metaplasia and gastric cancer. Currently, it has been determined that the regulation of many cellular processes involves ubiquitinylation of molecular effectors. The binding of ubiquitin allows the substrate to undergo a change in function, to interact within multimolecular signaling complexes and/or to be degraded. Dysregulation of the ubiquitinylation machinery contributes to several pathologies, including cancer. It is not understood in detail how H. pylori impacts the ubiquitinylation of host substrate proteins. The aim of this review is to summarize the existing literature in this field, with an emphasis on the role of E3 ubiquitin ligases in host cell homeodynamics, gastric pathophysiology and gastric cancer.

Hormone-Dependent Prostate Cancers are Dependent on Rac Signaling for Growth and Survival

Prostate cancer remains a common cause of cancer mortality in men. Initially, cancers are dependent of androgens for growth and survival. First line therapies reduce levels of circulating androgens or target the androgen receptor (AR) directly. Although most patients show durable responses, many patients eventually progress to castration-resistant prostate cancer (CRPC) creating a need for alternative treatment options. The Rac1 signaling pathway has previously been implicated as a driver of cancer initiation and disease progression. We investigated the role of HACE1, the E3 ubiquitin ligase for Rac1, in prostate cancer and found that HACE1 is commonly lost resulting in hyperactive Rac signaling leading to enhanced cellular proliferation, motility and viability. Importantly, we show that a Rac inhibitor can attenuate the growth and survival of prostate cancer cells. Rac signaling was also found to be critical in prostate cancers that express the AR. Rac inhibition in androgen dependent cells resulted in reduction of AR target gene expression suggesting that targeting Rac1 may be an alternative method for blocking the AR signaling axis. Finally, when used in combination with AR antagonists, Rac inhibition enhanced the suppression of AR target gene expression. Therefore, targeting Rac in prostate cancer has the potential to enhance the efficacy of approved AR therapies.

Loss of the Tumor Suppressor HACE1 Contributes to Cancer Progression

HACE1 belongs to the family of HECT domain-containing E3 ligases, which plays an important role in the occurrence, invasion and metastatic process in many human malignancies. HACE1 is a tumor suppressor gene that is reduced in most cancer tissues compared to adjacent normal tissue. The loss or knocking out of HACE1 leads to enhanced tumor growth, invasion, and metastasis; in contrast, the overexpression of HACE1 can inhibit the development of tumors. Hypermethylation reduces the expression of HACE1, thereby promoting tumor development. HACE1 can inhibit the development of inflammation or tumors via the ubiquitination pathway. Therefore, HACE1 may be a potential therapeutic target, providing new strategies for disease prevention and treatment.

HECT E3 ubiquitin ligases - emerging insights into their biological roles and disease relevance

Homologous to E6AP C-terminus (HECT) E3 ubiquitin ligases play a critical role in various cellular pathways, including but not limited to protein trafficking, subcellular localization, innate immune response, viral infections, DNA damage responses and apoptosis. To date, 28 HECT E3 ubiquitin ligases have been identified in humans, and recent studies have begun to reveal how these enzymes control various cellular pathways by catalyzing the post-translational attachment of ubiquitin to their respective substrates. New studies have identified substrates and/or interactors with different members of the HECT E3 ubiquitin ligase family, particularly for E6AP and members of the neuronal precursor cell-expressed developmentally downregulated 4 (NEDD4) family. However, there still remains many unanswered questions about the specific roles that each of the HECT E3 ubiquitin ligases have in maintaining cellular homeostasis. The present Review discusses our current understanding on the biological roles of the HECT E3 ubiquitin ligases in the cell and how they contribute to disease development. Expanded investigations on the molecular basis for how and why the HECT E3 ubiquitin ligases recognize and regulate their intracellular substrates will help to clarify the biochemical mechanisms employed by these important enzymes in ubiquitin biology.

An age-based, RNA expression paradigm for survival biomarker identification for pediatric neuroblastoma and acute lymphoblastic leukemia

Background

Pediatric cancer survival rates overall have been improving, but neuroblastoma (NBL) and acute lymphoblastic leukemia (ALL), two of the more prevalent pediatric cancers, remain particularly challenging. One issue not yet fully addressed is distinctions attributable to age of diagnosis.

Methods

In this report, we verified a survival difference based on diagnostic age for both pediatric NBL and pediatric ALL datasets, with younger patients surviving longer for both diseases. We identified several gene expression markers that correlated with age, along a continuum, and then used a series of age-independent survival metrics to filter these initial correlations.

Results

For pediatric NBL, we identified 2 genes that are expressed at a higher level in lower surviving patients with an older diagnostic age; and 4 genes that are expressed at a higher level in longer surviving patients with a younger diagnostic age. For pediatric ALL, we identified 3 genes expressed at a higher level in lower surviving patients with an older diagnostic age; and 17 genes expressed at a higher level in longer surviving patients with a younger diagnostic age.

Conclusions

This process implicated pan-chromosome effects for chromosomes 11 and 17 in NBL; and for the X chromosome in ALL.

Electronic supplementary material

The online version of this article (10.1186/s12935-019-0790-5) contains supplementary material, which is available to authorized users.

Demethylation of the HACE1 gene promoter inhibits the proliferation of human liver cancer cells

HECT domain and ankyrin repeat containing E3 ubiquitin protein ligase 1 (HACE1) is frequently downregulated or lost in numerous types of cancer, including liver cancer. The aim of the present study was to examine whether demethylation of the HACE1 gene could inhibit tumour progression. The expression of HACE1 was detected in liver cancer cell lines. Clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated (Cas)-based demethylation single guide RNAs for the HACE1 gene promoter were designed and transfected into liver cancer cells. Subsequently, proliferation was detected by MTT and colony formation assays, and optineurin (OPTN) ubiquitination and microtubule-associated proteins 1A/1B light chain 3B protein levels were detected by immunoblotting. The levels of HACE1 were significantly reduced in liver cancer cell lines compared with in a normal liver cell line. Demethylation of the HACE1 gene promoter increased HACE1 expression, inhibited the proliferation of liver cancer cells, and promoted OPTN ubiquitination and autophagy activity in liver cancer cells. In conclusion, activation of HACE1 expression by promoter demethylation may provide a suitable approach for anticancer therapy.