HSP90 inhibitor (NVP-AUY922) enhances the anti-cancer effect of BCL-2 inhibitor (ABT-737) in small cell lung cancer expressing BCL-2

Identification and validation of a glycosyltransferase gene signature as a novel prognostic model for lung adenocarcinoma

Background

The role of glycosyltransferase (GT) genes in lung adenocarcinoma (LUAD) needs further elucidation. Thus, our study aims to identify the prognostic gene signature of LUAD and explore its molecular functions.

Methods

We initially extracted GT gene sets from the database, and obtained mRNA expression levels and clinical data from The Cancer Genome Atlas (TCGA) database. For constructing a prognostic model for GT genes, we utilized univariate, least absolute shrinkage and selection operator (LASSO), and multivariate Cox regression analyses. Using the model, patients were categorized into high- and low-risk groups. Additionally, we evaluated differences in tumor immune infiltration between these groups and identified potential therapeutic drugs. Finally, we experimentally validated the expression levels of these crucial prognostic genes.

Results

We developed a risk score comprising nine GT genes (C1GALT1, FUT1, GALNT2, PLOD2, POMK, PYGB, ST3GAL6, UGT2B11, UGT3A1). Patients were then categorized into low- and high-risk groups based on this score. The low-risk group showed superior overall survival (OS) compared to the high-risk group. There were significantly distinct tumor immune microenvironment statuses observed between the two groups. We identified potential therapeutic drugs, including the MEK inhibitor (PD-184352). Finally, we verified the expression of these nine GT genes through immunohistochemistry (IHC) staining and quantitative real-time PCR (qPCR).

Conclusion

We identified a distinct LUAD GT gene signature, and these differentially expressed mRNAs could serve as valuable prognostic biomarkers and therapeutic targets. Furthermore, we experimentally validated their expression levels and identified potential therapeutic agents.

Targeted delivery of HSP90 inhibitors for efficient therapy of CD44-positive acute myeloid leukemia and solid tumor-colon cancer

Heat shock protein 90 (HSP90) is overexpressed in numerous cancers, promotes the maturation of numerous oncoproteins and facilitates cancer cell growth. Certain HSP90 inhibitors have entered clinical trials. Although less than satisfactory clinical effects or insurmountable toxicity have compelled these trials to be terminated or postponed, these results of preclinical and clinical studies demonstrated that the prospects of targeting therapeutic strategies involving HSP90 inhibitors deserve enough attention. Nanoparticulate-based drug delivery systems have been generally supposed as one of the most promising formulations especially for targeting strategies. However, so far, no active targeting nano-formulations have succeeded in clinical translation, mainly due to complicated preparation, complex formulations leading to difficult industrialization, incomplete biocompatibility or nontoxicity. In this study, HSP90 and CD44-targeted A6 peptide functionalized biomimetic nanoparticles (A6-NP) was designed and various degrees of A6-modification on nanoparticles were fabricated to evaluate targeting ability and anticancer efficiency. With no excipients, the hydrophobic HSP90 inhibitor G2111 and A6-conjugated human serum albumin could self-assemble into nanoparticles with a uniform particle size of approximately 200 nm, easy fabrication, well biocompatibility and avoidance of hepatotoxicity. Besides, G2111 encapsulated in A6-NP was only released less than 5% in 12 h, which may avoid off-target cell toxicity before entering into cancer cells. A6 peptide modification could significantly enhance uptake within a short time. Moreover, A6-NP continues to exert the broad anticancer spectrum of Hsp90 inhibitors and displays remarkable targeting ability and anticancer efficacy both in hematological malignancies and solid tumors (with colon tumors as the model cancer) both in vitro and in vivo. Overall, A6-NP, as a simple, biomimetic and active dual-targeting (CD44 and HSP90) nanomedicine, displays high potential for clinical translation.

Targeted Inhibition of Hsp90 in Combination with Metformin Modulates Programmed Cell Death Pathways in A549 Lung Cancer Cells

The pathophysiology of lung cancer is dependent on the dysregulation in the apoptotic and autophagic pathways. The intricate link between apoptosis and autophagy through shared signaling pathways complicates our understanding of how lung cancer pathophysiology is regulated. As drug resistance is the primary reason behind treatment failure, it is crucial to understand how cancer cells may respond to different therapies and integrate crosstalk between apoptosis and autophagy in response to them, leading to cell death or survival. Thus, in this study, we have tried to evaluate the crosstalk between autophagy and apoptosis in A549 lung cancer cell line that could be modulated by employing a combination therapy of metformin (6 mM), an anti-diabetic drug, with gedunin (12 µM), an Hsp90 inhibitor, to provide insights into the development of new cancer therapeutics. Our results demonstrated that metformin and gedunin were cytotoxic to A549 lung cancer cells. Combination of metformin and gedunin generated ROS and promoted MMP loss and DNA damage. The combination further increased the expression of AMPKα1 and promoted the nuclear localization of AMPKα1/α2. The expression of Hsp90 was downregulated, further decreasing the expression of its clients, EGFR, PIK3CA, AKT1, and AKT3. Inhibition of the EGFR/PI3K/AKT pathway upregulated TP53 and inhibited autophagy. The combination was promoting nuclear localization of p53; however, some cytoplasmic signals were also detected. Further increase in the expression of caspase 9 and caspase 3 was observed. Thus, we concluded that the combination of metformin and gedunin upregulates apoptosis by inhibiting the EGFR/PI3K/AKT pathway and autophagy in A549 lung cancer cells.

SIRT1 and HSP90α feed-forward circuit safeguards chromosome segregation integrity in diffuse large B cell lymphomas

Diffuse large B-cell lymphoma (DLBCL) is the most common aggressive non-Hodgkin lymphoma in adults, exhibiting highly heterogenous clinical behavior and complex molecular background. In addition to the genetic complexity, different DLBCL subsets exhibit phenotypic features independent of the genetic background. For example, a subset of DLBCLs is distinguished by increased oxidative phosphorylation and unique transcriptional features, including overexpression of certain mitochondrial genes and a molecular chaperone, heat shock protein HSP90α (termed "OxPhos" DLBCLs). In this study, we identified a feed-forward pathogenetic circuit linking HSP90α and SIRT1 in OxPhos DLBCLs. The expression of the inducible HSP90α isoform remains under SIRT1-mediated regulation. SIRT1 knockdown or chemical inhibition reduced HSP90α expression in a mechanism involving HSF1 transcription factor, whereas HSP90 inhibition reduced SIRT1 protein stability, indicating that HSP90 chaperones SIRT1. SIRT1-HSP90α interaction in DLBCL cells was confirmed by co-immunoprecipitation and proximity ligation assay (PLA). The number of SIRT1-HSP90α complexes in PLA was significantly higher in OxPhos- dependent than -independent cells. Importantly, SIRT1-HSP90α interactions in OxPhos DLBCLs markedly increased in mitosis, suggesting a specific role of the complex during this cell cycle phase. RNAi-mediated and chemical inhibition of SIRT1 and/or HSP90 significantly increased the number of cells with chromosome segregation errors (multipolar spindle formation, anaphase bridges and lagging chromosomes). Finally, chemical SIRT1 inhibitors induced dose-dependent cytotoxicity in OxPhos-dependent DLBCL cell lines and synergized with the HSP90 inhibitor. Taken together, our findings define a new OxPhos-DLBCL-specific pathogenetic loop involving SIRT1 and HSP90α that regulates chromosome dynamics during mitosis and may be exploited therapeutically.

Small-molecule dual inhibitors targeting heat shock protein 90 for cancer targeted therapy

Heat shock protein 90, also known as Hsp90, is an extensively preserved molecular chaperone that performs a critical function in organizing various biological pathways and cellular operations. As a potential drug target, Hsp90 is closely linked to cancer. Hsp90 inhibitors are a class of drugs that have been extensively studied in preclinical models and have shown promise in a variety of diseases, especially cancer. However, Hsp90 inhibitors have encountered several challenges in clinical development, such as low efficacy, toxicity, or drug resistance, few Hsp90 small molecule inhibitors have been approved worldwide. Nonetheless, combining Hsp90 inhibitors with other tumor inhibitors, such as HDAC inhibitors, tubulin inhibitors, and Topo II inhibitors, has been shown to have synergistic antitumor effects. Consequently, the development of Hsp90 dual-target inhibitors is an effective strategy in cancer treatment, as it enhances potency while reducing drug resistance. This article provides an overview of Hsp90's domain structure and biological functions, as well as a discussion of the design, discovery, and structure-activity relationships of Hsp90 dual inhibitors, aiming to provide insights into clinical drug research from a medicinal chemistry perspective and discover novel Hsp90 dual inhibitors.

The tumour-promoting role of protein homeostasis: Implications for cancer immunotherapy

Protein homeostasis, an important aspect of cellular fitness that encompasses the balance of production, folding and degradation of proteins, has been linked to several diseases of the human body. Multiple interconnected pathways coordinate to maintain protein homeostasis within the cell. Recently, the role of the protein homeostasis network in tumorigenesis and tumour progression has gradually come to light. Here, we summarize the involvement of the most prominent components of the protein quality control mechanisms (HSR, UPS, autophagy, UPR and ERAD) in tumour development and cancer immunity. In addition, evidence for protein quality control mechanisms and targeted drugs is outlined, and attempts to combine these drugs with cancer immunotherapy are discussed. Altogether, combination therapy represents a promising direction for future investigations, and this exciting insight will be further illuminated by the development of drugs that can reach a balance between the benefits and hazards associated with protein homeostasis interference.

TRAIP serves as a potential prognostic biomarker and correlates with immune infiltrates in lung adenocarcinoma

BACKGROUND

Lung adenocarcinoma (LUAD) is one of the major types of lung cancer with high morbidity and mortality. The TRAF-interacting protein (TRAIP) is a ring-type E3 ubiquitin ligase which has been recently identified to play pivotal roles in various cancers. However, the expression and function of TRAIP in LUAD remain elusive.

METHODS

In this study, we used bioinformatic tools as well as molecular experiments to explore the exact role of TRAIP and the underlying mechanism.

RESULTS

Data mining across the UALCAN, GEPIA and GTEx, GEO and HPA databases revealed that TRAIP was significantly overexpressed in LUAD tissues than that in adjacent normal tissues. Kaplan-Meier curve showed that high TRAIP expression was associated with poor overall survival (OS) and relapse-free survival (RFS). Univariate and multivariate cox regression analysis revealed that TRAIP was an independent risk factor in LUAD. And the TRAIP-based nomogram further supported the prognostic role of TRAIP in LUAD. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis demonstrated that TRAIP-associated genes were mainly involved in DNA replication, cell cycle and other processes. The immune infiltration analysis indicated that TRAIP expression was tightly correlated with the infiltration of diverse immune cell types, including B cell, CD8 + T cell, neutrophil and dendritic cell. Moreover, TRAIP expression was observed to be significantly associated with tumor infiltrating lymphocytes (TILs) and immune checkpoint molecules. In vitro experiments further confirmed knockdown of TRAIP inhibited cell migration and invasion, as well as decreasing chemokine production and inhibiting M2-like macrophage recruitment. Lastly, CMap analysis identified 10 small molecule compounds that may target TRAIP, providing potential therapies for LUAD.

CONCLUSIONS

Collectively, our study found that TRAIP is an oncogenic gene in LUAD, which may be a potential prognostic biomarker and promising therapeutic target for LUAD.

A Coumarin-Imidazothiadiazole Derivative, SP11 Abrogates Tumor Growth by Targeting HSP90 and Its Client Proteins

Despite several treatment options for blood cancer, mortality remains high due to relapse and the disease's aggressive nature. Elevated levels of HSP90, a molecular chaperone essential for protein folding, are associated with poor prognosis in leukemia and lymphoma. HSP90 as a target for chemotherapy has been met with limited success due to toxicity and induction of heat shock. This study tested the activity of an HSP90 inhibitor, SP11, against leukemic cells, mouse lymphoma allograft, and xenograft models. SP11 induced cytotoxicity in vitro in leukemic cell lines and induced cell death via apoptosis, with minimal effect on normal cells. SP11 induced cell death by altering the status of HSP90 client proteins both in vitro and in vivo. SP11 reduced the tumor burden in allograft and xenograft mouse models without apparent toxicity. The half-life of SP11 in the plasma was approximately 2 h. SP11 binding was observed at both the N-terminal and C-terminal domains of HSP90. C-terminal binding was more potent than N-terminal binding of HSP90 in silico and in vitro using isothermal calorimetry. SP11 bioavailability and minimal toxicity in vivo make it a potential candidate to be developed as a novel anticancer agent.

Artificial intelligence-based identification of octenidine as a Bcl-xL inhibitor

Apoptosis plays an essential role in maintaining cellular homeostasis and preventing cancer progression. Bcl-xL, an anti-apoptotic protein, is an important modulator of the mitochondrial apoptosis pathway and is a promising target for anticancer therapy. In this study, we identified octenidine as a novel Bcl-xL inhibitor through structural feature-based deep learning and molecular docking from a library of approved drugs. The NMR experiments demonstrated that octenidine binds to the Bcl-2 homology 3 (BH3) domain-binding hydrophobic region that consists of the BH1, BH2, and BH3 domains in Bcl-xL. A structural model of the Bcl-xL/octenidine complex revealed that octenidine binds to Bcl-xL in a similar manner to that of the well-known Bcl-2 family protein antagonist ABT-737. Using the NanoBiT protein-protein interaction system, we confirmed that the interaction between Bcl-xL and Bak-BH3 domains within cells was inhibited by octenidine. Furthermore, octenidine inhibited the proliferation of MCF-7 breast and H1299 lung cancer cells by promoting apoptosis. Taken together, our results shed light on a novel mechanism in which octenidine directly targets anti-apoptotic Bcl-xL to trigger mitochondrial apoptosis in cancer cells.

Effective synthesis of novel dihydrobenzisoxazoles bearing the 2-aminothiazole moiety and evaluation of the antiproliferative activity of their acylated derivatives

An effective method for the synthesis of 8-aryl-4,5-dihydrothiazolo[4',5':3,4]benzo[1,2-c]isoxazol-2-amines was developed. This method includes the α-keto bromination of 3-aryl-6,7-dihydrobenzo[c]isoxazol-4(5H)-ones followed by the condensation of the obtained bromo derivatives with thiourea in acetonitrile. Using virtual screening, a series of acylated derivatives of the obtained compounds were selected as potential HSP90 inhibitors. These compounds were prepared and evaluated as antiproliferative agents against three cancer cell lines (A431, 22Rv1, and MCF-7). Compounds 8b, 8c and 8q exhibiting high antiproliferative potency against MCF-7 breast cancer cells with IC₅₀ values ranging from 2.3 to 9.5 μM were chosen for in-depth evaluation. The selected compounds had remarkable effects on HSP90 client proteins, including steroid hormone receptors and the anti-apoptotic factor BCL2. The obtained compounds are of interest for anticancer drug development.

LAM-003, a new drug for treatment of tyrosine kinase inhibitor-resistant FLT3-ITD-positive AML

Acute myeloid leukemias (AML) harboring a constitutively active internal tandem duplication (ITD) mutation in the FMS-like kinase tyrosine kinase (FLT3) receptor are associated with poor patient prognosis. Despite initial clinical responses to FLT3 kinase inhibitors, patients eventually relapse. Mechanisms of resistance include the acquisition of secondary FLT3 mutations and protective stromal signaling within the bone marrow niche. Here we show that LAM-003, a prodrug of the heat shock protein 90 inhibitor LAM-003A, has cytotoxic activity against AML cell lines and primary samples harboring FLT3-ITD. LAM-003 regressed tumors in an MV-4-11 xenograft mouse model and extended survival in a MOLM-13 systemic model. LAM-003 displayed synergistic activity with chemotherapeutic drugs and FLT3 inhibitors, with the most robust synergy being obtained with venetoclax, a BCL-2 inhibitor. This finding was verified in a MOLM-13 systemic survival model in which the combination significantly prolonged survival compared with the single agents. Importantly, LAM-003 exhibited equipotent activity against FLT3 inhibitor-resistant mutants of FLT3, such as D835 or F691, in cytotoxic and FLT3 degradation assays. LAM-003 also retained potency in AML cells grown in stromal-conditioned media that were resistant to FLT3 inhibitors. Lastly, a genome-wide CRISPR screen revealed epigenetic regulators, including KDM6A, as determinants of LAM-003 sensitivity in AML cell lines, leading to the discovery of synergy with an EZH2 inhibitor. Collectively, these preclinical findings support the use of LAM-003 in FLT3-ITD patients with AML who no longer respond to FLT3 inhibitor therapy either as a single agent or in combination with drugs known to be active in AML.

Opportunities and obstacles of targeted therapy and immunotherapy in small cell lung cancer

Small cell lung cancer (SCLC) is an aggressive malignant tumour which accounts for approximately 13-15% of all newly diagnosed lung cancer cases. To date, platinum-based chemotherapy are still the first-line treatments for SCLC. However, chemotherapy resistance and systemic toxicity limit the long-term clinical outcome of first-line treatment in SCLC. Recent years, targeted therapy and immunotherapy have made great breakthrough in cancer therapy, and researchers aim to exploit both as a single agent or in combination with chemotherapy to improve the survival of SCLC patients, but limited effectiveness and the adverse events remain the major obstacles in the treatment of SCLC. To overcome these challenges for SCLC therapies, prevention and early diagnosis for this refractory disease is very important. At the same time, we should reveal more information about the pathogenesis of SCLC and the mechanism of drug resistance. Finally, new treatment strategies should also be taken into considerations, such as repurposing drug, optimising of targets, combination therapy strategies or prognostic biomarkers to enhance therapeutic effects and decrease the adverse events rates in SCLC patients. This article will review the molecular biology characteristics of SCLC and discuss the opportunities and obstacles of the current therapy for SCLC patients.

The HSP90 inhibitor Onalespib exerts synergistic anti-cancer effects when combined with radiotherapy: an in vitro and in vivo approach

Oncogenic client-proteins of the chaperone Heat shock protein 90 (HSP90) insure unlimited tumor growth and are involved in resistance to chemo- and radiotherapy. The HSP90 inhibitor Onalespib initiates the degradation of oncoproteins, and might also act as a radiosensitizer. The aim of this study was therefore to evaluate the efficacy of Onalespib in combination with external beam radiotherapy in an in vitro and in vivo approach. Onalespib downregulated client proteins, lead to increased apoptosis and caused DNA-double-strands. Monotherapy and combination with radiotherapy reduced colony formation, proliferation and migration assessed in radiosensitive HCT116 and radioresistant A431 cells. In vivo, a minimal treatment regimen for 3 consecutive days of Onalespib (3 × 10 mg/kg) doubled survival, whereas Onalespib with radiotherapy (3 × 2 Gy) caused a substantial delay in tumor growth and prolonged the survival by a factor of 3 compared to the HCT116 xenografted control group. Our results demonstrate that Onalespib exerts synergistic anti-cancer effects when combined with radiotherapy, most prominent in the radiosensitive cell models. We speculate that the depletion and downregulation of client proteins involved in signalling, migration and DNA repair mechanisms is the cause. Thus, individually, or in combination with radiotherapy Onalespib inhibits tumor growth and has the potential to improve radiotherapy outcomes, prolonging the overall survival of cancer patients.

CpG Oligodeoxynucleotide Promotes Apoptosis of Human Bladder Cancer T24 Cells Via Inhibition of the Antiapoptotic Factors

Objective:

Unmethylated cytosine-phosphorothioate-guanine oligodeoxynucleotide, a synthetic oligodeoxynucleotide, has been used as an adjuvant in clinic and in the antitumor activity. However, the antitumor mechanism of cytosine-phosphorothioate-guanine oligodeoxynucleotide against human bladder cancer is unknown. The purpose of this study is to evaluate the cytotoxicity and molecular mechanism of anticancer effect of cytosine-phosphorothioate-guanine oligodeoxynucleotide on T24 cells (a human bladder cancer cell line).

Methods:

The cytotoxic activity of cytosine-phosphorothioate-guanine oligodeoxynucleotide was examined by cell viability assay in the presence and absence of 5-fluorouracil, respectively. Apoptosis and cell-cycle phase distribution were detected by flow cytometry analysis. To investigate the molecular mechanisms of cytosine-phosphorothioate-guanine oligodeoxynucleotide cytotoxicity, the expression of antiapoptotic factors (B-cell lymphoma-2 and Survivin, β-actin as control) in RNA, and protein level was assayed by quantitative real-time polymerase chain reaction and automated capillary Western blot.

Results:

The inhibition ratio of T24 cells treated with both cytosine-phosphorothioate-guanine oligodeoxynucleotide and 5-fluorouracil was higher than those treated with either cytosine-phosphorothioate-guanine oligodeoxynucleotide or 5-fluorouracil alone. In the combination group (cytosine-phosphorothioate-guanine oligodeoxynucleotide and 5-fluorouracil), the apoptosis rate was significantly increased, and more cells were arrested at “S” and “G2/M” phases compared to those in cytosine-phosphorothioate-guanine oligodeoxynucleotide or 5-fluorouracil alone. Furthermore, the expression of antiapoptotic factors was decreased by cytosine-phosphorothioate-guanine oligodeoxynucleotide alone or combined with 5-fluorouracil.

Conclusion:

Cytosine-phosphorothioate-guanine oligodeoxynucleotide promoted apoptosis and enhanced the chemosensitivity of 5-fluorouracil in T24 cells. Cytosine-phosphorothioate-guanine oligodeoxynucleotide downregulated the expression of antiapoptotic factors and inhibited cell-cycle phase by arresting more cells at “S” and “G2/M” phases. This study indicated the potential ability of cytosine-phosphorothioate-guanine oligodeoxynucleotide as a candidate drug for human bladder cancer.

Heat Shock Proteins: Agents of Cancer Development and Therapeutic Targets in Anti-Cancer Therapy

Heat shock proteins (HSPs) constitute a large family of molecular chaperones classified by their molecular weights, and they include HSP27, HSP40, HSP60, HSP70, and HSP90. HSPs function in diverse physiological and protective processes to assist in maintaining cellular homeostasis. In particular, HSPs participate in protein folding and maturation processes under diverse stressors such as heat shock, hypoxia, and degradation. Notably, HSPs also play essential roles across cancers as they are implicated in a variety of cancer-related activities such as cell proliferation, metastasis, and anti-cancer drug resistance. In this review, we comprehensively discuss the functions of HSPs in association with cancer initiation, progression, and metastasis and anti-cancer therapy resistance. Moreover, the potential utilization of HSPs to enhance the effects of chemo-, radio-, and immunotherapy is explored. Taken together, HSPs have multiple clinical usages as biomarkers for cancer diagnosis and prognosis as well as the potential therapeutic targets for anti-cancer treatment.

Chaperoning STAT3/5 by Heat Shock Proteins: Interest of Their Targeting in Cancer Therapy

While cells from multicellular organisms are dependent upon exogenous signals for their survival, growth, and proliferation, commitment to a specific cell fate requires the correct folding and maturation of proteins, as well as the degradation of misfolded or aggregated proteins within the cell. This general control of protein quality involves the expression and the activity of molecular chaperones such as heat shock proteins (HSPs). HSPs, through their interaction with the STAT3/STAT5 transcription factor pathway, can be crucial both for the tumorigenic properties of cancer cells (cell proliferation, survival) and for the microenvironmental immune cell compartment (differentiation, activation, cytokine secretion) that contributes to immunosuppression, which, in turn, potentially promotes tumor progression. Understanding the contribution of chaperones such as HSP27, HSP70, HSP90, and HSP110 to the STAT3/5 signaling pathway has raised the possibility of targeting such HSPs to specifically restrain STAT3/5 oncogenic functions. In this review, we present how HSPs control STAT3 and STAT5 activation, and vice versa, how the STAT signaling pathways modulate HSP expression. We also discuss whether targeting HSPs is a valid therapeutic option and which HSP would be the best candidate for such a strategy.

PADI3 plays an antitumor role via the Hsp90/CKS1 pathway in colon cancer

BACKGROUND

CKS1 is highly expressed in colon cancer tissues, and is essential for cancer cell proliferation. The downstream molecular mechanism of CKS1 has been fully studied, but the upstream regulatory mechanism of it is still unclear. Earlier research found that PADI3 plays its anti-tumor roles via suppress cell proliferation, in this study, we found that the expression pattern of PADI3 and CKS1 are negatively correlated in colon cancer tissues, and overexpression of PADI3 can partly reverse CKS1 induced cancer cell proliferation. However, the regulatory mechanism of PADI3 and CKS1 in the tumorigenesis of colon cancer is still unclear and need to do further research.

METHODS

Western blot and real-time PCR were used to detect the expression levels of genes. CCK-8 and colony formation assays were used to examine cell proliferation and colony formation ability. Overexpression and rescue experiments were used to study the molecular mechanism of CKS1 in colon cancer cells, BALB/c nude mice were used to study the function of CKS1 in vivo.

RESULTS

CKS1 is highly expressed in colon cancer tissues, and the overexpression of CKS1 promotes cell proliferation and colony formation in both HCT116 (originating from primary colon cancer) and SW620 (originating from metastatic tumor nodules of colon cancer) cells. CKS1-expressing HCT116 cells produced larger tumors than the control cells. The expression pattern of PADI3 and CKS1 are negatively correlation in clinical samples of colon cancer, further study indicates that PADI3 can significantly decrease Hsp90 and CKS1 expression, and Hsp90 is essential for PADI3 to downregulate CKS1expression in colon cancer cells.

CONCLUSIONS

PADI3 exerts its antitumor activity by inhibiting Hsp90 and CKS1 expression, and Hsp90 is essential for PADI3 to suppress CKS1 expression.

Transcriptional regulation of Bcl-2 gene by the PR/SET domain family member PRDM10

Bcl-2 (B-cell lymphoma 2) protein is localized in the outer membrane of mitochondria, where it plays an important role in promoting cellular survival and inhibiting the actions of pro-apoptotic proteins. PRDM10 is a member of the PR/SET family of epigenetic regulators and may play a role in development and cell differentiation. Here we show that human PRDM10 contributes to the transcriptional regulation of human Bcl-2 gene. We found that PRDM10-depletion in human cells reduced the expression of Bcl-2 protein and over-expression of PRDM10 promoted Bcl-2 protein expression. Furthermore, luciferase reporter activity of Bcl-2 gene P1 promoter was significantly increased in cells co-transfected with PRDM10, and PRDM10 was able to bind to the Bcl-2 P1 promoter in vivo. Using The Cancer Genome Atlas (TCGA) data set, we found weak positive correlation between PRDM10 and Bcl-2 in several cancer types including cancers of the breast, colon, and lung tissues. These data identify a novel function for PRDM10 protein and provide insights on the transcriptional control of Bcl-2 expression.

Ell3 functions as a critical decision maker at the crossroad between stem cell senescence and apoptosis

Background

Ell3 is a RNA polymerase II elongation factor that has various cell type-dependent functions, such as regulating the differentiation efficiency of embryonic stem cells and sensitizing cancer cells to anticancer drugs. However, there has been little research on the role of Ell3 on the regulation of senescence and apoptosis of stem cells.

Methods

We analyzed the senescence of Ell3-suppressed stem cells by mitochondrial activity, β-gal (+) cells, and lineage differentiation efficiency. The apoptosis of Ell3-overexpressing stem cells was analyzed by Annexin V staining, Immunoblot, and Live&dead assay. In addition, chromatin immunoprecipitation and luciferase assays were used to demonstrate p53 functions as a direct transcriptional activator of Ell3.

Results

Suppression of Ell3 expression induced senescence in stem cells by increasing Bcl-2 expression. Unlike the effect of Ell3 suppression, the ectopic expression of Ell3 induces apoptosis of stem cells and induces apoptosis of adjacent cells. In addition, p53 functions as a direct transcriptional activator of Ell3 during the stem cell apoptosis.

Conclusions

We suggest that the function of Ell3 is associated with the p53-Bcl2 axis in both senescent and apoptotic ADSCs.

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1137-9) contains supplementary material, which is available to authorized users.

Developmental Exposure to Di-(2-ethylhexyl) Phthalate Induces Cerebellar Granule Cell Apoptosis via the PI3K/AKT Signaling Pathway

Di-(2-ethylhexyl) phthalate (DEHP) is an ubiquitous environmental contaminant because of its extensive use in plastics and its persistence. As an environmental endocrine disruptor, it is suspected to interfere with neurodevelopment in people. However, evidence of the effects of maternal DEHP exposure on cerebellar development in offspring is scarce. The objective of this study was to investigate maternal exposure to DEHP and its effect on apoptosis of cerebellar granule cells (CGCs) and related mechanisms. Pregnant Wistar rats were administrated DEHP (0, 30, 300 and 750 mg/kg/d) by gavage from gestational day (GD) 0 to postnatal day (PN) 21. Primary CGCs were also exposed to mono-(2-ethylhexyl) phthalate (MEHP), the main metabolite of DEHP, for 24 h with concentrations of 0, 25, 100 and 250 µM. The CGCs of male offspring from 300 and 750 mg/kg/d DEHP exposure groups showed significantly increased apoptosis. In addition, the PI3K/AKT signaling pathway was inhibited in the male offspring of the 300 and 750 mg/kg/d DEHP exposure groups. However, effects on female pups were not obvious. Apoptosis was also elevated and the PI3K/AKT signaling pathway was inhibited after primary CGCs were exposed to MEHP. Furthermore, apoptosis was reduced after treatment with the PI3K/AKT signaling pathway activator, insulin-like growth factor (IGF) 1, and increased after treatment with LY294002, an inhibitor of the PI3K/AKT signaling pathway. These results suggested that maternal DEHP exposure induced apoptosis in the CGCs of male pups via the PI3K/AKT signaling pathway, and the apoptosis could be rescued by IGF1 and aggravated by LY294002.

KCNQ1OT1 facilitates progression of non-small-cell lung carcinoma via modulating miRNA-27b-3p/HSP90AA1 axis

Long noncoding RNA KCNQ1OT1 participates in the regulation of imprinted genes within the kcnq1 domain. But its roles in carcinogenesis and metastasis remain largely elusive. Herein, we evaluated its potential in non-small-cell lung cancer (NSCLC) progression. We demonstrated that the KCNQ1OT1 level was upregulated in NSCLC tissues and cell lines. High KCNQ1OT1 level correlated with poor overall and progression-free survival in NSCLC patients. KCNQ1OT1 facilitated proliferation, migration, and invasion in H460 cells. Furthermore, knockdown of KCNQ1OT1 reduced the expression of HSP90AA1. KCNQ1OT1 presented a positive correlation with HSP90AA1 which predicted the tumor progression in NSCLC from The Cancer Genome Atlas database. Intriguingly, KCNQ1OT1 modulated HSP90AA1 expression by sponging miR-27b-3p. MiR-27b-3p counteracted the effect of KCNQ1OT1 on HSP90AA1 expression, H460 cell migration, and invasion. These data revealed a role for KCNQ1OT1 as an oncogene through miR-27b-3p/HSP90AA1 axis during NSCLC progression.

Secreted Heat Shock Protein 90α Attenuated the Effect of Anticancer Drugs in Small-Cell Lung Cancer Cells Through AKT/GSK3β/β-Catenin Signaling

Small-cell lung cancer (SCLC) represents the progressive form of lung cancer. Patients with SCLC have poor prognosis, partially due to drug resistance. Therefore, understanding the underlying mechanism for drug resistance in SCLC is needed to improve clinical outcomes. The concentrations of heat shock protein 90α (HSP90α) in medium were detected by enzyme-linked immunosorbent assay. The protein levels were detected by Western blot. Cell apoptosis was detected by propidium iodide staining in cell lines or terminal deoxynucleotidyl transferase dUTP nick end labeling staining in tumor sections. Doxorubicin (DOX) was administered into cultured cell lines or intraperitoneally injected into xenograft mouse to induce apoptosis. In SCLC cell lines, either DOX or ABT-737 increased extracellular HSP90α levels, which attenuated the percentage of apoptotic cells. Extracellular HSP90α activated Ak strain transforming (AKT) and β-catenin signaling and inhibited glycogen synthase kinase 3β (GSK3β) signaling. In the xenograft mouse model, extracellular HSP90α promoted tumor development and inhibited apoptosis of tumor cells. Heat shock protein 90α attenuates the efficacy of anticancer drugs in SCLC cells through AKT/GSK3β/β-catenin signaling.