Hematopoietic PBX-interacting protein is a substrate and an inhibitor of the APC/C-Cdc20 complex and regulates mitosis by stabilizing cyclin B1

KCNN1 promotes proliferation and metastasis of breast cancer via ERLIN2-mediated stabilization and K63-dependent ubiquitination of Cyclin B1

Potassium Calcium-Activated Channel Subfamily N1 (KCNN1), an integral membrane protein, is thought to regulate neuronal excitability by contributing to the slow component of synaptic after hyperpolarization. However, the role of KCNN1 in tumorigenesis has been rarely reported, and the underlying molecular mechanism remains unclear. Here, we report that KCNN1 functions as an oncogene in promoting breast cancer cell proliferation and metastasis. KCNN1 was overexpressed in breast cancer tissues and cells. The pro-proliferative and pro-metastatic effects of KCNN1 were demonstrated by CCK8, clone formation, Edu assay, wound healing assay and transwell experiments. Transcriptomic analysis using KCNN1 overexpressing cells revealed that KCNN1 could regulate key signaling pathways affecting the survival of breast cancer cells. KCNN1 interacts with ERLIN2 and enhances the effect of ERLIN2 on Cyclin B1 stability. Overexpression of KCNN1 promoted the protein expression of Cyclin B1, enhanced its stability and promoted its K63 dependent ubiquitination, while knockdown of KCNN1 had the opposite effects on Cyclin B1. Knockdown (or overexpression) ERLNI2 partially restored Cyclin B1 stability and K63 dependent ubiquitination induced by overexpression (or knockdown) of KCNN1. Knockdown (or overexpression) ERLIN2 also partially neutralizes the effects of overexpression (or knockdown) KCNN1-induced breast cancer cell proliferation, migration and invasion. In paired breast cancer clinical samples, we found a positive expression correlations between KCNN1 and ERLIN2, KCNN1 and Cyclin B1, as well as ERLIN2 and Cyclin B1. In conclusion, this study reveals, for the first time, the role of KCNN1 in tumorigenesis and emphasizes the importance of KCNN1/ERLIN2/Cyclin B1 axis in the development and metastasis of breast cancer.

HPIP and RUFY3 are noncanonical guanine nucleotide exchange factors of Rab5 to regulate endocytosis-coupled focal adhesion turnover

While the role of endocytosis in focal adhesion turnover-coupled cell migration has been established in addition to its conventional role in cellular functions, the molecular regulators and precise molecular mechanisms that underlie this process remain largely unknown. In this study, we report that proto-oncoprotein hematopoietic PBX-interacting protein (HPIP) localizes to focal adhesions as well as endosomal compartments along with RUN FYVE domain-containing protein 3 (RUFY3) and Rab5, an early endosomal protein. HPIP contains two coiled-coil domains (CC1 and CC2) that are necessary for its association with Rab5 and RUFY3 as CC domain double mutant, that is, mtHPIPΔCC1-2 failed to support it. Furthermore, we show that HPIP and RUFY3 activate Rab5 by serving as noncanonical guanine nucleotide exchange factors of Rab5. In support of this, either deletion of coiled-coil domains or silencing of HPIP or RUFY3 impairs Rab5 activation and Rab5-dependent cell migration. Mechanistic studies further revealed that loss of HPIP or RUFY3 expression severely impairs Rab5-mediated focal adhesion disassembly, FAK activation, fibronectin-associated-β1 integrin trafficking, and thus cell migration. Together, this study underscores the importance of HPIP and RUFY3 as noncanonical guanine nucleotide exchange factors of Rab5 and in integrin trafficking and focal adhesion turnover, which implicates in cell migration.

CDC20 inhibition alleviates fibrotic response of renal tubular epithelial cells and fibroblasts by regulating nuclear translocation of β-catenin

Fibrosis is a common pathological phenomenon in progressive kidney disease leading to eventual loss of kidney function. Previous studies demonstrated that CDC20 plays a role in cancers by regulating epithelial-mesenchymal transition (EMT) and the infiltration of fibroblasts, suggesting the potential of CDC20 in regulating fibrotic response. However, the role of CDC20 in renal fibrosis is yet unclear. Herein, we reported that renal CDC20 was remarkably upregulated in renal tubular epithelial cells and fibroblasts in chronic kidney disease (CKD) patients, which was in line with a positive correlation with the severity of kidney fibrosis. In mice with unilateral urinary obstruction, CDC20 was also strikingly enhanced, and treatment with Apcin, an inhibitor of CDC20, ameliorated kidney fibrosis. Consistently, the pharmacological inhibition of CDC20 in mouse proximal tubular epithelial cells and rat fibroblasts attenuated TGF-β1-induced fibrotic responses, while overexpression of CDC20 aggravated such responses. Additional studies revealed that CDC20 induces nuclear translocation of β-catenin, which in turn initiates and promotes the pathological process of fibrosis in CKD. Thus, enhanced CDC20 in renal tubular cells and fibroblasts promotes renal fibrosis by activating β-catenin, and CDC20 inhibition may serve as a promising strategy for the prevention and treatment of renal fibrosis.

CDC20: a novel therapeutic target in cancer

Cell division cycle protein 20 (Cdc20) is a member of the cell cyclin family. In the early stage of mitosis, it activates the anaphase-promoting complex (APC) and forms the E3 ubiquitin ligase complex APC^Cdc20, which destroys key regulators of the cell cycle and promotes mitosis. Cdc20 serves as a target for the spindle checkpoint, ensuring proper chromosome segregation. As an oncoprotein, Cdc20 is highly expressed in a variety of malignant tumors, and Cdc20 overexpression is associated with poor prognosis of these tumors. This review aims to dissect the tumorigenic role of Cdc20 in human malignancies and its targeting strategies.

Identification of biomarkers and key pathways in synovial sarcoma cells exposed to anlotinib by integrating bioinformatics analysis and experimental validation

OBJECTIVE

To identify potential biomarkers, key pathways and modules following the exposure of synovial sarcoma (SS) cells to anlotinib.

METHODS

In the current study, we integrated multiple bioinformatics methods to identify the hub genes and key pathways associated with the effects of anlotinib treatment in SS cells. In addition, we used reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR) to validate the expression levels of the identified hub genes in SS cells treated with anlotinib.

RESULTS

In total, 183 differentially expressed genes (DEGs) were identified, of which 47 were upregulated and 136 were downregulated. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses showed that the DEGs were predominantly involved in cell division and cell cycle progression. A total of two modules were identified from the protein-protein interaction network using the MCODE plugin in Cytoscape, where module 1 was the most significant. By combining the results of CytoHubba analysis based on the module 1 and The Cancer Genome Atlas database, six real hub genes, cyclin (CCN) A2, kinesin family member 2C, cell division cycle 20, CCNB2, aurora kinase B and CCNB1, were identified. Subsequent GO and KEGG pathway analysis revealed that these six real hub genes were significantly associated with the cell cycle and mitosis. Finally, RT-qPCR verified that the mRNA expression levels of these six real hub genes were significantly decreased in SS cells treated with anlotinib compared with those in the control group. Altogether, our study identified biomarkers and key pathways associated with the effects of anlotinib treatment in SS cells, which may provide novel insights into the underlying mechanism of anlotinib treatment in SS.

CDC20 in and out of mitosis: a prognostic factor and therapeutic target in hematological malignancies

Cell division cycle 20 homologue (CDC20) is a well-known regulator of cell cycle, as it controls the correct segregation of chromosomes during mitosis. Many studies have focused on the biological role of CDC20 in cancer development, as alterations of its functionality have been linked to genomic instability and evidence demonstrated that high CDC20 expression levels are associated with poor overall survival in solid cancers. More recently, novel CDC20 functions have been demonstrated or suggested, including the regulation of apoptosis and stemness properties and a correlation with immune cell infiltration. Here, we here summarize and discuss the role of CDC20 inside and outside mitosis, starting from its network of interacting proteins. In the last years, CDC20 has also attracted more interest in the blood cancer field, being overexpressed and showing an association with prognosis both in myeloid and lymphoid malignancies. Preclinical findings showed that selective CDC20 and APC/C^CDC20/APC/C^CDH1 inhibitors, namely Apcin and proTAME, are effective against lymphoma and multiple myeloma cells, resulting in mitotic arrest and apoptosis and synergizing with clinically-relevant drugs. The evidence and hypothesis presented in this review provide the input for further biological and chemical studies aiming to dissect novel potential CDC20 roles and targeting strategies in hematological malignancies.

Construction of miRNA-mRNA regulatory network and analysis of hub genes in oral squamous cell carcinoma

BACKGROUND

Oral squamous cell carcinoma (OSCC) severely affects the quality of life and the 5-year survival rate is low. Exploring the potential miRNA-mRNA regulatory network and analyzing hub genes and clinical data can provide a theoretical basis for further elucidating the pathogenesis of OSCC.

METHODS

The miRNA expression datasets of GSE113956 and GSE124566 and mRNA expression datasets of GSE31056, GSE37991 and GSE13601 were obtained from the Gene Expression Omnibus databases. The differentially expressed miRNAs (DEMs) and mRNAs (DEGs) were screened using GEO2R. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed by DAVID database. The PPI network was established through STRING database and the hub genes were preliminarily screened out by Cytoscape software. After identifying the hub genes in the TCGA database, we predicted the potential DEM transcription factors, constructed a miRNA-mRNA regulatory network, and analyzed the relationship between the hub genes and clinical data.

RESULTS

A total of 28 DEMs and 764 DEGs were screened out, which were composed of 285 up-regulated genes and 479 down-regulated genes. Enrichment analysis showed that up-regulation of DEGs were mainly enriched in extracellular matrix organization and cancer-related pathway, while down-regulation of DEGs were mainly enriched in muscular system process and adrenaline signal transduction. After preliminary screening by PPI network and identification in TCGA, the up-regulated FN1, COL1A1, COL1A2, AURKA, CCNB1, CCNA2, SPP1, CDC6, and down-regulated ACTN2, TTN, IGF1, CAV3, MYL2, DMD, LDB3, CSRP3, ACTA1, PPARG were identified as hub genes. The miRNA-mRNA regulation network showed that hsa-miR-513b was the DEM with the most regulation, and COL1A1 was the DEG with the most regulation. In addition, CDC6, AURKA, CCNB1 and CCNA2 were related to overall survival and tumor differentiation.

CONCLUSIONS

The regulatory relationship of hsa-miR-513b/ CDC6, CCNB1, CCNA2 and the regulatory relationship of hsa-miR-342-5p /AURKA were not only verified in the miRNA-mRNA regulatory network but also related to overall survival and tumor differentiation. These results indicated that they participated in the cellular regulatory process, and provided a molecular mechanism model for the study of pathogenesis.

Targeting mitochondria as a therapeutic anti-gastric cancer approach

Gastric cancer is regarded as the fifth most common cancer globally but the third most common cancer death. Although systemic chemotherapy is the primary treatment for advanced gastric cancer patients, the outcome of chemotherapy is unsatisfactory. Novel therapeutic strategies and potential alternative treatments are therefore needed to overcome the impact of this disease. At a cellular level, mitochondria play an important role in cell survival and apoptosis. A growing body of studies have shown that mitochondria play a central role in the regulation of cellular function, metabolism, and cell death during carcinogenesis. Interestingly, the impact of mitochondrial dynamics, including fission/fusion and mitophagy, on carcinogenesis and cancer progression has also been reported, suggesting the potential targeting of mitochondrial dynamics for the treatment of cancer. This review not only comprehensively summarizes the homeostasis of gastric cancer cells, but the potential therapeutic interventions for the targeting of mitochondria for gastric cancer therapy are also highlighted and discussed.

A reciprocal feedback loop between HIF-1α and HPIP controls phenotypic plasticity in breast cancer cells

While phenotypic plasticity is a critical factor contributing to tumor heterogeneity, molecular mechanisms underlying this process are largely unknown. Here we report that breast cancer cells display phenotypic diversity in response to hypoxia or normoxia microenvironments by operating a reciprocal positive feedback regulation of HPIP and HIF-1α. We show that under hypoxia, HIF-1α induces HPIP expression that establishes cell survival, and also promotes cell migration/invasion, EMT and metastatic phenotypes in breast cancer cells. Mechanistic studies revealed that HPIP interacts with SRP14, a component of signal recognition particle, and stimulates MMP9 synthesis under hypoxic stress. Whereas, in normoxia, HPIP stabilizes HIF-1α, causing the Warburg effect to support cell growth. Concurrently, mathematical modelling corroborates this reciprocal feedback loop in enabling cell-state transitions in cancer cells. Clinical data indicate that elevated levels of HPIP and HIF-1α correlate with unfavorable prognosis and shorter survival rates in breast cancer subjects. Together, this data shows a reciprocal positive feedback loop between HPIP and HIF-1α that was unknown hitherto. It unveils how the tumor microenvironment influences phenotypic plasticity that has an impact on tumor growth and metastasis and, further signifies considering this pathway as a potential therapeutic target in breast cancer.

Hematopoietic PBX-interacting protein is a novel regulator of mammary epithelial cell differentiation

Hematopoietic PBX-interacting protein (HPIP, also known as PBXIP1) is an estrogen receptor (ER) interacting protein that regulates estrogen-mediated breast cancer cell proliferation and tumorigenesis. However, its functional significance in the context of mammary gland development is unexplored. Here, we report that HPIP is required for prolactin (PRL)-induced lactogenic differentiation in vitro. Molecular analysis of HPIP expression in mice revealed its induced expression at pregnancy and lactation stages of mammary gland. Moreover, PRL is a lactogenic hormone that controls pregnancy as well as lactation and induces Hpip/Pbxip1 expression in a signal transducer and activator of transcription 5a-dependent manner. Using mammary epithelial and lactogenic-competent cell lines, we further show that HPIP plays a regulatory role in PRL-mediated mammary epithelial cell differentiation, which is measured by acini formation, β-casein synthesis, and lipid droplet formation. Further mechanistic studies using pharmacological inhibitors revealed that HPIP modulates PRL-induced β-casein synthesis via phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) activation. This study also identified HPIP as a critical regulator of autocrine PRL signaling as treatment with the PRL receptor antagonist Δ1-9-G129R-hPRL restrained HPIP-mediated PRL synthesis, AKT activation, and β-casein synthesis in cultured HC11 cells. Interestingly, we also uncovered that microRNA-148a (miR-148a) antagonizes HPIP-mediated mammary epithelial cell differentiation. Together, our study identified HPIP as a critical regulator of PRL signaling and revealed a novel molecular circuitry involving PRL, HPIP, PI3K/AKT, and miR-148a that controls mammary epithelial cell differentiation in vitro.

A novel chemical inhibitor suppresses breast cancer cell growth and metastasis through inhibiting HPIP oncoprotein

Increasing evidence suggests the pivotal role of hematopoietic pre-B-cell leukemia transcription factor (PBX)-interacting protein (HPIP/PBXIP1) in cancer development and progression, indicating that HPIP inhibition may be a promising target for cancer therapy. Here, we screened compounds inhibiting breast cancer cell proliferation with HPIP fused with green fluorescent protein as a reporter. A novel agent named TXX-1-10 derived from rimonabant, an antagonist of cannabinoid receptor 1 with anticancer effects, has been discovered to reduce HPIP expression and has greater inhibitory effects on breast cancer cell growth and metastasis in vitro and in vivo than rimonabant. TXX-1-10 regulates HPIP downstream targets, including several important kinases involved in cancer development and progression (e.g., AKT, ERK1/2, and FAK) as well as cell cycle-, apoptosis-, migration-, and epithelial-to-mesenchymal transition (EMT)-related genes. Consistent with the results of anticancer effects, genome-wide RNA sequencing indicated that TXX-1-10 has more significant effects on regulation of the expression of genes related to DNA replication, cell cycle, apoptosis, cell adhesion, cell migration, and invasion than rimonabant. In addition, TXX-1-10 significantly regulated genes associated with the cell growth and extracellular matrix organization, many of which were shown to be regulated by HPIP. Moreover, compared with rimonabant, TXX-1-10 greatly reduces blood-brain barrier penetrability to avoid adverse central depressive effects. These findings suggest that HPIP inhibition may be a useful strategy for cancer treatment and TXX-1-10 is a promising candidate drug for cancer therapy.

HPIP protooncogene differentially regulates metabolic adaptation and cell fate in breast cancer cells under glucose stress via AMPK and RNF2 dependent pathways

While cancer cells rewire metabolic pathways to sustain growth and survival under metabolic stress in solid tumors, the molecular mechanisms underlying these processes remain largely unknown. In this study, cancer cells switched from survival to death during the early to late phases of metabolic stress by employing a novel signaling switch from AMP activated protein kinase (AMPK)-Forkhead box O3 (FOXO3a)-hematopoietic PBX1-interacting protein (HPIP) to the ring finger protein 2 (RNF2)-HPIP-ubiquitin (Ub) pathway. Acute metabolic stress induced proto-oncogene HPIP expression in an AMPK-FOXO3a-dependent manner in breast cancer (BC) cells. HPIP depletion reduced cell survival and tumor formation in mouse xenografts, which was accompanied by diminished intracellular ATP levels and increased apoptosis in BC cells in response to metabolic (glucose) stress. Glutamine flux (¹³C-labeled) analysis further suggested that HPIP rewired glutamine metabolism by controlling the expression of the solute carrier family 1 member 5 (SLC1A5) and glutaminase (GLS) genes by acting as a coactivator of MYC to ensure cell survival upon glucose deprivation. However, in response to chronic glucose stress, HPIP was ubiquitinated by the E3-Ub ligase, RNF2, and was concomitantly degraded by the proteasome-mediated pathway, ensuring apoptosis. In support of these data, clinical analyses further indicated that elevated levels of HPIP correlated with AMPK activation in BC. Taken together, these data suggest that HPIP is a signal coordinator during metabolic stress and thus serves as a potential therapeutic target in BC.

Two decades of a protooncogene HPIP/PBXIP1: Uncovering the tale from germ cell to cancer

Hematopoietic PBX interacting protein (HPIP or pre-B-cell leukemia transcription factor interacting protein (PBXIP1) was discovered two decades ago as a corepressor of pre-B-cell leukemia homeobox (PBX) 1 with a vital functional role in hematopoiesis. Later it emerged as a potential biomarker of poor prognosis and tumorigenesis for more than a dozen different cancers. It regulates aggressive cancer phenotypes, cell proliferation, metastasis, EMT, etc. The anomaly in the regulation of HPIP is linked with physiological disorders like renal fibrosis, chronic kidney disease and osteoarthritis. Scientists have unraveled more than twenty interacting proteins of HPIP and its functional role in various physiological and cellular processes that involves normal neuronal development, embryogenesis, endometrium decidualization, and germ cell proliferation. Over the past 20 years, we have witnessed the emerging role of HPIP and its association with a myriad of cellular activities ranging from germ cell proliferation to cancer aggressiveness, modulating multitude of signaling cascades like TGF-β1, PI3K/AKT, Wnt, mTOR, and Sonic hedgehog signaling pathways. This review will give the current understanding of HPIP, in terms of its diverse functions, theoretical ideas, and further explore cellular links and promising areas that need to be investigated. We also provide a comprehensive overview of the transcript variants of HPIP and distinct sets of transcription factors regulating their expression, which may help to understand the role of HPIP in various cellular or physiological conditions.

The Insulin Receptor Adaptor IRS2 is an APC/C Substrate That Promotes Cell Cycle Protein Expression and a Robust Spindle Assembly Checkpoint

Insulin receptor substrate 2 (IRS2) is an essential adaptor that mediates signaling downstream of the insulin receptor and other receptor tyrosine kinases. Transduction through IRS2-dependent pathways is important for coordinating metabolic homeostasis, and dysregulation of IRS2 causes systemic insulin signaling defects. Despite the importance of maintaining proper IRS2 abundance, little is known about what factors mediate its protein stability. We conducted an unbiased proteomic screen to uncover novel substrates of the Anaphase Promoting Complex/Cyclosome (APC/C), a ubiquitin ligase that controls the abundance of key cell cycle regulators. We found that IRS2 levels are regulated by APC/C activity and that IRS2 is a direct APC/C target in G1 Consistent with the APC/C's role in degrading cell cycle regulators, quantitative proteomic analysis of IRS2-null cells revealed a deficiency in proteins involved in cell cycle progression. We further show that cells lacking IRS2 display a weakened spindle assembly checkpoint in cells treated with microtubule inhibitors. Together, these findings reveal a new pathway for IRS2 turnover and indicate that IRS2 is a component of the cell cycle control system in addition to acting as an essential metabolic regulator.

Effective in vitro delivery of paclitaxel by nanocargo of mesoporous polycaprolactone against triple negative breast cancer cells by minimalizing drug dose

Among the breast cancers, triple negative breast cancer (TNBC) has relatively poor outcomes with a lower survival rate and personalised chemotherapy is the only option available for treatment. Currently in the biomedical domain, nanomaterials with porous morphology have revealed their tremendous possibilities to be used as a nanocarrier in treating cancer by offering void space to encapsulate/entrap biological agents. However, the development of nanocarrier-based targeted therapy with high therapeutic efficacy and fewer side effects to normal cells is always a challenge. Here, we have developed nanocargos based on biodegradable mesoporous PCL (polycaprolactone) of approx. diameter of 75 nm by template removal synthesis techniques. Succeeding the comparative analysis of the nanocarriers, the efficiencies of core shell PCL-mZnO (PZ) and mesoporous PCL (HPZ) to deliver paclitaxel (Taxol/T) into breast cancer cells, is investigated. We found that HPZ nanocapsules have less cytotoxicity and drug loading efficiency of about 600 μg mg⁻¹. The Taxol-loaded nanoparticles (T-HPZ) have exhibited more cytotoxicity than Taxol alone treated cancer cells. Furthermore, T-HPZ treated MDA-MB231 cells are accumulated at G2/M phase of the cell cycle and eventually undergo apoptosis. In support of this, anchorage independent growth of MDA-MB231 cells are significantly inhibited by T-HPZ treatment. Together, our findings suggest that T-HPZ-based paclitaxel (Taxol/T) loaded nanoparticles provide a novel therapeutic option in the treatment of TNBC.

Porous-PCL-nanocapsules-Taxol is an effective nanomedicine for the treatment of triple negative breast cancer which can reduce the extent of side effects also.