Hypoxia-induced p53 modulates both apoptosis and radiosensitivity via AKT

Myeloid Deficiency of Heparan Sulfate 6-O-Endosulfatases Impairs Bone Marrow Hematopoiesis

The heparan sulfate (HS) 6-O-endosulfatases or the Sulfs (Sulf1 and Sulf2) are the only known enzymes that can modify HS sulfation status extracellularly and have been shown to regulate diverse biological processes. The role of the Sulfs in bone marrow (BM) hematopoiesis is not known. In this study, we generated a novel mouse line with myeloid-specific deletion of the Sulfs by crossing Sulf1/2 double floxed mice with the LysM-cre line. The LysM-Sulf knockout (KO) male mice exhibited age-dependent expansion of hematopoietic stem cells and the granulocyte-monocyte lineages in the BM, whereas common lymphoid progenitors and B lymphocyte populations were significantly reduced. Although megakaryocytic and erythroid progenitors were not reduced in the BM, the LysM-Sulf KO males suffered age-dependent reduction of red blood cells (RBCs) and platelets in the peripheral blood, suggesting that the production of RBCs and platelets was arrested at later stages. In addition, LysM-Sulf KO males displayed progressive splenomegaly with extramedullary hematopoiesis. Compared to males, LysM-Sulf KO females exhibited a much-reduced phenotype, and ovariectomy had little effect. Mechanistically, reduced TGF-β/Smad2 but enhanced p53/p21 signaling were observed in male but not female LysM-Sulf KO mice. Finally, HS disaccharide analysis via LC-MS/MS revealed increased HS 6-O-sulfation in the BM from both male and female LysM-Sulf KO mice, however, the distribution of 6-O-sulfated motifs were different between the sexes with compensatory increase in Sulf1 expression observed only in LysM-Sulf KO females. In conclusion, our study reveals that myeloid deficiency of the Sulfs leads to multilineage abnormalities in BM hematopoiesis in an age- and sex-dependent manner.

Differential effect of plakoglobin in restoring the tumor suppressor activities of p53-R273H vs. p53-R175H mutants

The six most common missense mutations in the DNA binding domain of p53 are known as "hot spots" and include two of the most frequently occurring p53 mutations (p53-R175H and p53-R273H). p53 stability and function are regulated by various post-translational modifications such as phosphorylation, acetylation, sumoylation, methylation, and interactions with other proteins including plakoglobin. Previously, using various carcinoma cell lines we showed that plakoglobin interacted with wild-type and several endogenous p53 mutants (e.g., R280K, R273H, S241F, S215R, R175H) and restored their tumor suppressor activities in vitro. Since mutant p53 function is both mutant-specific and cell context-dependent, we sought herein, to determine if plakoglobin tumor suppressive effects on exogenously expressed p53-R273H and p53-R175H mutants are similarly maintained under the same genetic background using the p53-null and plakoglobin-deficient H1299 cell line. Functional assays were performed to assess colony formation, migration, and invasion while immunoblotting and qPCR were used to examine the subcellular distribution and expression of specific proteins and genes that are typically regulated by or regulate p53 function and are altered in mutant p53-expressing cell lines and tumors. We show that though, plakoglobin interacted with both p53-R273H and p53-R175H mutants, it had a differential effect on the transcription and subcellular distribution of their gene targets and their overall oncogenic properties in vitro. Notably, we found that plakoglobin's tumor suppressive effects were significantly stronger in p53-R175H expressing cells compared to p53-R273H cells. Together, our results indicate that exploring plakoglobin interactions with p53-R175H may be useful for the development of cancer therapeutics focused on the restoration of p53 function.

Hypoxia triggers cardiomyocyte apoptosis via regulating the m6A methylation-mediated LncMIAT/miR-708-5p/p53 axis

Long-time hypoxia induced cardiomyocyte apoptosis is an important mechanism of myocardial ischemia (MI) injury. Interestingly, long noncoding RNA myocardial infarction-associated transcript (LncMIAT) has been involved in the regulation of MI injury; however, the underlying mechanism by which LncMIAT affects the progression of hypoxia-induced cardiomyocyte apoptosis remains unclear. In the present study, hypoxia was found to promote cardiomyocyte apoptosis through an increased expression of LncMIAT in vitro. Biological investigations and dual-luciferase gene reporter assay further revealed that LncMIAT was able to bind with miR-708-5p to upregulate the p53-mediated cell death of the cardiomyocytes. Silencing of LncMIAT or overexpression of miR-708-5p led to a significant reduction in p53-mediated cardiomyocyte apoptosis. The methylated RNA immunoprecipitation (MeRIP)-qPCR results showed that hypoxia exerted its effects on LncMIAT through AKLBH5-N6-methyladenosine (m6A) methylation and therefore hypoxia was shown to trigger HL-1 cardiomyocyte apoptosis via the m6A methylation-mediated LncMIAT/miR-708-5p/p53 axis. Silencing of AKLBH5 significantly alleviated the m6A methylation-mediated LncMIAT upregulation and p53-mediated cardiomyocyte apoptosis, while promoted miR-708-5p expression. Taken together, the present study highlighted that LncMIAT could act as a key biological target during hypoxia-induced cardiomyocyte apoptosis. In addition, it was shown that hypoxia could promote cardiomyocyte apoptosis through regulation of the m6A methylation-mediated LncMIAT/miR-708-5p/p53 signaling axis.

Dichotomous transactivation domains contribute to growth inhibitory and promotion functions of TAp73

The transcription factor p73, a member of the p53 tumor-suppressor family, regulates cell death and also supports tumorigenesis, although the mechanistic basis for the dichotomous functions is poorly understood. We report here the identification of an alternate transactivation domain (TAD) located at the extreme carboxyl (C) terminus of TAp73β, a commonly expressed p73 isoform. Mutational disruption of this TAD significantly reduced TAp73β's transactivation activity, to a level observed when the amino (N)-TAD that is similar to p53's TAD, is mutated. Mutation of both TADs almost completely abolished TAp73β's transactivation activity. Expression profiling highlighted a unique set of targets involved in extracellular matrix-receptor interaction and focal adhesion regulated by the C-TAD, resulting in FAK phosphorylation, distinct from the N-TAD targets that are common to p53 and are involved in growth inhibition. Interestingly, the C-TAD targets are also regulated by the oncogenic, amino-terminal-deficient DNp73β isoform. Consistently, mutation of C-TAD reduces cellular migration and proliferation. Mechanistically, selective binding of TAp73β to DNAJA1 is required for the transactivation of C-TAD target genes, and silencing DNAJA1 expression abrogated all C-TAD-mediated effects. Taken together, our results provide a mechanistic basis for the dichotomous functions of TAp73 in the regulation of cellular growth through its distinct TADs.

Transcriptomic and proteomic study of cancer cell lines exposed to actinomycin D and nutlin-3a reveals numerous, novel candidates for p53-regulated genes

Transcriptomic analyses have revealed hundreds of p53-regulated genes; however, these studies used a limited number of cell lines and p53-activating agents. Therefore, we searched for candidate p53-target genes by employing stress factors and cell lines never before used in a high-throughput search for p53-regulated genes. We performed RNA-Seq on A549 cells exposed to camptothecin, actinomycin D, nutlin-3a, as well as a combination of actinomycin D and nutlin-3a (A + N). The latter two substances synergise upon the activation of selected p53-target genes. A similar analysis was performed on other cell lines (U-2 OS, NCI-H460, A375) exposed to A + N. To identify proteins in cell lysates or those secreted into a medium of A549 cells in control conditions or treated with A + N, we employed mass spectrometry. The expression of selected genes strongly upregulated by A + N or camptothecin was examined by RT-PCR in p53-deficient cells and their controls. We found that p53 participates in the upregulation of: ACP5, APOL3, CDH3, CIBAR2, CRABP2, CTHRC1, CTSH, FAM13C, FBXO2, FRMD8, FRZB, GAST, ICOSLG, KANK3, KCNK6, KLRG2, MAFB, MR1, NDRG4, PTAFR, RETSAT, TMEM52, TNFRSF14, TRANK1, TYSND1, WFDC2, WFDC5, WNT4 genes. Twelve of these proteins were detected in the secretome and/or proteome of treated cells. Our data generated new hypotheses concerning the functioning of p53. Many genes activated by A + N or camptothecin are also activated by interferons, indicating a noticeable overlap between transcriptional programs of p53 and these antiviral cytokines. Moreover, several identified genes code for antagonists of WNT/β-catenin signalling pathways, which suggests new connections between these two cancer-related signalling systems. One of these antagonists is DRAXIN. Previously, we found that its gene is activated by p53. In this study, using mass spectrometry and Western blotting, we detected expression of DRAXIN in a medium of A549 cells exposed to A + N. Thus, this protein functions not only in the development of the nervous system, but it may also have a new cancer-related function.

Identification of hypoxic-related lncRNAs prognostic model for revealing clinical prognostic and immune infiltration characteristic of cutaneous melanoma

BACKGROUND

Cutaneous melanoma (CM) remains a significant threat to human health. There are clues to the potential role of hypoxia in CM progression. However, the role of hypoxia-related lncRNAs (HRLs) in CM has not been clarified.

METHODS

We obtained hypoxia related genes from MSigDB database and subsequently identified HRLs by applying TCGA database. LASSO-univariate and multivariate Cox analysis were used to comprehensively analyze the survival characteristics and HRLs expressions, and a novel HRLs-related prognostic risk model was subsequently established for comprehensive analysis.

RESULTS

The established risk model could evaluate the clinical outcome of CM accurately. The ability of the model-related risk score was also validated as an independent prognostic indicator of CM. Immune infiltration, TMB analysis, drug sensitivity analysis and immunotherapy evaluation were conducted to comprehensively assess the possible causes of the difference in prognosis. The reliability of bioinformatics results was partially verified by RT-qPCR.

CONCLUSION

We established a new HRLs related risk model and discussed the potential role of hypoxia in the development of CM, which provided a novel basis for CM risk stratification.

Antibody-Based Imaging of Bioreductive Prodrug Release in Hypoxia

Regions of hypoxia occur in most tumors and are a predictor of poor patient prognosis. Hypoxia-activated prodrugs (HAPs) provide an ideal strategy to target the aggressive, hypoxic, fraction of a tumor, while protecting the normal tissue from toxicity. A key challenge associated with the development of novel HAPs, however, is the ability to visualize the delivery of the prodrug to hypoxic regions and determine where it has been activated. Here, we report a modified version of the commonly used nitroimidazole bioreductive group that incorporates the fluoroethyl epitope of the antibody-based hypoxia imaging agent, EF5. Attachment of this group to the red fluorescent dye, dicyanomethylene (DCM), enabled us to correlate the release of the DCM dye with imaging of the reduced bioreductive group using the EF5 antibody. This study confirmed that the antibody was imaging reduction and fragmentation of the pro-fluorophore. We next employed the modified bioreductive group to synthesize a new prodrug of the KDAC inhibitor Panobinostat, EF5-Pano. Release of EF5-Pano in hypoxic multiple myeloma cells was imaged using the EF5 antibody, and the presence of an imaging signal correlated with apoptosis and a reduction in cell viability. Therefore, EF5-Pano is an imageable HAP with a proven cytotoxic effect in multiple myeloma, which could be utilized in future in vivo experiments.

Coordination-driven FBXW7 DNAzyme-Fe nanoassembly enables a binary switch of breast cancer cell cycle checkpoint responses for enhanced ferroptosis-radiotherapy

Radiotherapy is a mainstream modality for breast cancer treatment that employs ionizing radiation (IR) to damage tumor cell DNA and elevate ROS stress, which demonstrates multiple clinically-favorable advantages including localized treatment and low invasiveness. However, breast cancer cells may activate the p53-mediated cell cycle regulation in response to radiotherapy to repair IR-induced cellular damage and facilitate post-treatment survival. F-Box and WD Repeat Domain Containing 7 (FBXW7) is a promoter of p53 degradation and critical nexus of cell proliferation and survival events. Herein, we engineered a cooperative radio-ferroptosis-stimulatory nanomedicine through coordination-driven self-assembly between ferroptosis-inducing Fe2+ ions and FBXW7-inhibiting DNAzymes and further modification of tumor-targeting dopamine-modified hyaluronic acid (HA). The nanoassembly could be selectively internalized by breast cancer cells and disintegrated in lysosomes to release the therapeutic payload. DNAzyme readily abolishes FBXW7 expression and stabilizes phosphorylated p53 to cause irreversible G2 phase arrest for amplifying post-IR tumor cell apoptosis. Meanwhile, the p53 stabilization also inhibits the SLC7A11-cystine-GSH axis, which combines with the IR-upregulated ROS levels to amplify Fe2+-mediated ferroptotic damage. The DNAzyme-Fe-HA nanoassembly could thus systematically boost the tumor cell damaging effects of IR, presenting a simple and effective approach to augment the response of breast cancer to radiotherapy. STATEMENT OF SIGNIFICANCE: To overcome the intrinsic radioresistance in breast cancer, we prepared co-assembly of Fe2+ and FBXW7-targeted DNAzymes and modified surface with dopamine conjugated hyaluronic acid (HA), which enabled tumor-specific FBXW7-targeted gene therapy and ferroptosis therapy in IR-treated breast cancers. The nanoassembly could be activated in acidic condition to release the therapeutic contents. Specifically, the DNAzymes could selectively degrade FBXW7 mRNA in breast cancer cells to simultaneously induce accumulation of p53 and retardation of NHEJ repair, eventually inducing irreversible cell cycle arrest to promote apoptosis. The p53 stabilization would also inhibit the SLC7A11/GSH/GPX4 axis to enhance Fe2+ mediated ferroptosis. These merits could act in a cooperative manner to induce pronounced tumor inhibitory effect, offering new approaches for tumor radiosensitization in the clinics.

The potential mechanism of Choulingdan mixture in improving acute lung injury based on HPLC-Q-TOF-MS, network pharmacology and in vivo experiments

Choulingdan mixture (CLDM) is an empirical clinical prescription for the adjuvant treatment of acute lung injury (ALI). CLDM has been used for almost 30 years in the clinic. However, its mechanism for improving ALI still needs to be investigated. In this study, high-performance liquid chromatography-quadrupole/time-of-flight mass spectrometry (HPLC-Q-TOF-MS/MS) was applied to characterize the overall chemical composition of CLDM. A total of 93 ingredients were characterized, including 25 flavonoids, 20 organic acids, 11 saponins, nine terpenoids, seven tannins and 21 other compounds. Then network pharmacology was applied to predict the potential bioactive components, target genes and signaling pathways of CLDM in improving ALI. Additionally, molecular docking was performed to demonstrate the interaction between the active ingredients and the disease targets. Finally, animal experiments further confirmed that CLDM significantly inhibits pulmonary inflammation, pulmonary edema and oxidative stress in lipopolysaccharide-induced ALI mice by inhibiting the PI3K-AKT signaling pathway. This study enhanced the amount and accuracy of compounds of CLDM and provided new insights into CLDM preventing and treating ALI.

RUNX1-Regulated Signaling Pathways in Ovarian Cancer

Ovarian cancer is the leading cause of gynecological death worldwide, and its poor prognosis and high mortality seriously affect the life of ovarian cancer patients. Runt-related transcription factor 1 (RUNX1) has been widely studied in hematological diseases and plays an important role in the occurrence and development of hematological diseases. In recent years, studies have reported the roles of RUNX1 in solid tumors, including the significantly increased expression of RUNX1 in ovarian cancer. In ovarian cancer, the dysregulation of the RUNX1 signaling pathway has been implicated in tumor progression, metastasis, and response to therapy. At the same time, the decreased expression of RUNX1 in ovarian cancer can significantly improve the sensitivity of clinical chemotherapy and provide theoretical support for the subsequent diagnosis and treatment target of ovarian cancer, providing prognosis and treatment options to patients with ovarian cancer. However, the role of RUNX1 in ovarian cancer remains unclear. Therefore, this article reviews the relationship between RUNX1 and the occurrence and development of ovarian cancer, as well as the closely regulated signaling pathways, to provide some inspiration and theoretical support for future research on RUNX1 in ovarian cancer and other diseases.

Characterizing the role of Phlda3 in the development of acute toxicity and malignant transformation of hematopoietic cells induced by total-body irradiation in mice

The tumor suppressor p53 is a transcriptional factor that plays a crucial role in controlling acute toxicity and long-term malignant transformation of hematopoietic cells induced by genotoxic stress such as ionizing radiation. Among all transcriptional targets of p53, one gene that is robustly induced by radiation is the pleckstrin homology domain-only protein Phlda3. However, the role that Phlda3 plays in regulating the response of hematopoietic cells to radiation is unknown. Here, using isogenic cell lines and genetically engineered mouse models, we showed that radiation induces Phlda3 in human leukemia cells and mouse normal hematopoietic cells in a p53-dependent manner. However, deletion of the Phlda3 gene did not ameliorate radiation-induced acute hematologic toxicity. In addition, distinct from mice that lose p53, loss of Phlda3 did not alter the latency and incidence of radiation-induced thymic lymphoma in mice. Remarkably, whole-exome sequencing data showed that lymphomas in irradiated Phlda3+/+ mice harbor a significantly higher number of single nucleotide variants (SNVs) and indels compared to lymphomas in irradiated Phlda3+/- and Phlda3-/- littermates. Together, our results indicate that although deletion of Phlda3 does not accelerate the development of radiation-induced thymic lymphoma, fewer SNVs and indels are necessary to initiate lymphomagenesis after radiation exposure when Phlda3 is silenced.

The mechanism and clinical application of DNA damage repair inhibitors combined with immune checkpoint inhibitors in the treatment of urologic cancer

Urologic cancers such as kidney, bladder, prostate, and uroepithelial cancers have recently become a considerable global health burden, and the response to immunotherapy is limited due to immune escape and immune resistance. Therefore, it is crucial to find appropriate and effective combination therapies to improve the sensitivity of patients to immunotherapy. DNA damage repair inhibitors can enhance the immunogenicity of tumor cells by increasing tumor mutational burden and neoantigen expression, activating immune-related signaling pathways, regulating PD-L1 expression, and reversing the immunosuppressive tumor microenvironment to activate the immune system and enhance the efficacy of immunotherapy. Based on promising experimental results from preclinical studies, many clinical trials combining DNA damage repair inhibitors (e.g., PARP inhibitors and ATR inhibitors) with immune checkpoint inhibitors (e.g., PD-1/PD-L1 inhibitors) are underway in patients with urologic cancers. Results from several clinical trials have shown that the combination of DNA damage repair inhibitors with immune checkpoint inhibitors can improve objective rates, progression-free survival, and overall survival (OS) in patients with urologic tumors, especially in patients with defective DNA damage repair genes or a high mutational load. In this review, we present the results of preclinical and clinical trials of different DNA damage repair inhibitors in combination with immune checkpoint inhibitors in urologic cancers and summarize the potential mechanism of action of the combination therapy. Finally, we also discuss the challenges of dose toxicity, biomarker selection, drug tolerance, drug interactions in the treatment of urologic tumors with this combination therapy and look into the future direction of this combination therapy.

PTBP1 controls intestinal epithelial regeneration through post-transcriptional regulation of gene expression

The intestinal epithelial regeneration is driven by intestinal stem cells under homeostatic conditions. Differentiated intestinal epithelial cells, such as Paneth cells, are capable of acquiring multipotency and contributing to regeneration upon the loss of intestinal stem cells. Paneth cells also support intestinal stem cell survival and regeneration. We report here that depletion of an RNA-binding protein named polypyrimidine tract binding protein 1 (PTBP1) in mouse intestinal epithelial cells causes intestinal stem cell death and epithelial regeneration failure. Mechanistically, we show that PTBP1 inhibits neuronal-like splicing programs in intestinal crypt cells, which is critical for maintaining intestinal stem cell stemness. This function is achieved at least in part through promoting the non-productive splicing of its paralog PTBP2. Moreover, PTBP1 inhibits the expression of an AKT inhibitor PHLDA3 in Paneth cells and permits AKT activation, which presumably maintains Paneth cell plasticity and function in supporting intestinal stem cell niche. We show that PTBP1 directly binds to a CU-rich region in the 3' UTR of Phlda3, which we demonstrate to be critical for downregulating the mRNA and protein levels of Phlda3. Our results thus reveal the multifaceted in vivo regulation of intestinal epithelial regeneration by PTBP1 at the post-transcriptional level.

Developmental diversity and unique sensitivity to injury of lung endothelial subtypes during postnatal growth

At birth, the lung is still immature, heightening susceptibility to injury but enhancing regenerative capacity. Angiogenesis drives postnatal lung development. Therefore, we profiled the transcriptional ontogeny and sensitivity to injury of pulmonary endothelial cells (EC) during early postnatal life. Although subtype speciation was evident at birth, immature lung EC exhibited transcriptomes distinct from mature counterparts, which progressed dynamically over time. Gradual, temporal changes in aerocyte capillary EC (CAP2) contrasted with more marked alterations in general capillary EC (CAP1) phenotype, including distinct CAP1 present only in the early alveolar lung expressing Peg3, a paternally imprinted transcription factor. Hyperoxia, an injury that impairs angiogenesis induced both common and unique endothelial gene signatures, dysregulated capillary EC crosstalk, and suppressed CAP1 proliferation while stimulating venous EC proliferation. These data highlight the diversity, transcriptomic evolution, and pleiotropic responses to injury of immature lung EC, possessing broad implications for lung development and injury across the lifespan.

Encoding and Decoding of p53 Dynamics in Cellular Response to Stresses

In the cellular response to stresses, the tumor suppressor p53 is activated to maintain genomic integrity and fidelity. As a transcription factor, p53 exhibits rich dynamics to allow for discrimination of the type and intensity of stresses and to direct the selective activation of target genes involved in different processes including cell cycle arrest and apoptosis. In this review, we focused on how stresses are encoded into p53 dynamics and how the dynamics are decoded into cellular outcomes. Theoretical modeling may provide a global view of signaling in the p53 network by coupling the encoding and decoding processes. We discussed the significance of modeling in revealing the mechanisms of the transition between p53 dynamic modes. Moreover, we shed light on the crosstalk between the p53 network and other signaling networks. This review may advance the understanding of operating principles of the p53 signaling network comprehensively and provide insights into p53 dynamics-based cancer therapy.

TNF Signaling Is Required for Castration-Induced Vascular Damage Preceding Prostate Cancer Regression

The mainstay treatment for locally advanced, recurrent, or metastatic prostate cancer (PrCa) is androgen deprivation therapy (ADT). ADT causes prostate cancers to shrink in volume, or regress, by inducing epithelial tumor cell apoptosis. In normal, non-neoplastic murine prostate, androgen deprivation via castration induces prostate gland regression that is dependent on TNF signaling. In addition to this direct mechanism of action, castration has also been implicated in an indirect mechanism of prostate epithelial cell death, which has been described as vascular regression. The initiating event is endothelial cell apoptosis and/or increased vascular permeability. This subsequently leads to reduced blood flow and perfusion, and then hypoxia, which may enhance epithelial cell apoptosis. Castration-induced vascular regression has been observed in both normal and neoplastic prostates. We used photoacoustic, power Doppler, and contrast-enhanced ultrasound imaging, and CD31 immunohistochemical staining of the microvasculature to assess vascular integrity in the period immediately following castration, enabling us to test the role of TNF signaling in vascular regression. In two mouse models of androgen-responsive prostate cancer, TNF signaling blockade using a soluble TNFR2 ligand trap reversed the functional aspects of vascular regression as well as structural changes in the microvasculature, including reduced vessel wall thickness, cross-sectional area, and vessel perimeter length. These results demonstrate that TNF signaling is required for vascular regression, most likely by inducing endothelial cell apoptosis and increasing vessel permeability. Since TNF is also the critical death receptor ligand for prostate epithelial cells, we propose that TNF is a multi-purpose, comprehensive signal within the prostate cancer microenvironment that mediates prostate cancer regression following androgen deprivation.

p53 Modulates Radiosensitivity in Head and Neck Cancers-From Classic to Future Horizons

p53, initially considered a tumor suppressor, has been the subject of research related to cancer treatment resistance in the last 30 years. The unfavorable response to multimodal therapy and the higher recurrence rate, despite an aggressive approach, make HNSCC a research topic of interest for improving therapeutic outcomes, even if it is only the sixth most common malignancy worldwide. New advances in molecular biology and genetics include the involvement of miRNA in the control of the p53 pathway, the understanding of mechanisms such as gain/loss of function, and the development of different methods to restore p53 function, especially for HPV-negative cases. The different ratio between mutant p53 status in the primary tumor and distant metastasis originating HNSCC may serve to select the best therapeutic target for activating an abscopal effect by radiotherapy as a "booster" of the immune system. P53 may also be a key player in choosing radiotherapy fractionation regimens. Targeting any pathway involving p53, including tumor metabolism, in particular the Warburg effect, could modulate the radiosensitivity and chemo-sensitivity of head and neck cancers.

A Novel m7G-Related Genes-Based Signature with Prognostic Value and Predictive Ability to Select Patients Responsive to Personalized Treatment Strategies in Bladder Cancer

Although N7-methylguanosine (m7G) modification serves as a tumor promoter in bladder cancer (BLCA), the comprehensive role of m7G-related characterization in BLCA remains unclear. In this study, we systematically evaluated the m7G-related clusters of 760 BLCA patients through consensus unsupervised clustering analysis. Next, we investigated the underlying m7G-related genes among these m7G-related clusters. Univariate Cox and LASSO regressions were used for screening out prognostic genes and for reducing the dimension, respectively. Finally, we developed a novel m7G-related scoring system via the GSVA algorithm. The correlation between tumor microenvironment, prediction of personalized therapies and this m7G-related signature was gradually revealed. We first identified three m7G-related clusters and 1108 differentially expressed genes relevant to the three clusters. Based on the profile of 1108 genes, we divided BLCA patients into two clusters, which were quantified by our established m7G-related scoring system. Patients with higher m7G-related scores tended to have a better OS and more chances to benefit from immunotherapy. A significantly negative connection between sensitivity to classic chemotherapeutic drugs and m7G-related signature was uncovered. In summary, our data show that m7G-related characterization of BLCA patients can be of value for prognostic stratification and for patient-oriented therapeutic options, designing personalized treatment strategies in the preclinical setting.

Apoptotic vesicles activate autophagy in recipient cells to induce angiogenesis and dental pulp regeneration

Extracellular vesicles (EVs) derived from living cells play important roles in donor cell-induced recipient tissue regeneration. Although numerous studies have found that cells undergo apoptosis after implantation in an ischemic-hypoxic environment, the roles played by the EVs released by apoptotic cells are largely unknown. In this study, we obtained apoptotic vesicles (apoVs) derived from human deciduous pulp stem cells and explored their effects on the dental pulp regeneration process. Our work showed that apoVs were ingested by endothelial cells (ECs) and elevated the expression of angiogenesis-related genes, leading to pulp revascularization and tissue regeneration. Furthermore, we found that, at the molecular level, apoV-carried mitochondrial Tu translation elongation factor was transported and regulated the angiogenic activation of ECs via the transcription factor EB-autophagy pathway. In a beagle model of dental pulp regeneration in situ, apoVs recruited endogenous ECs and facilitated the formation of dental-pulp-like tissue rich in blood vessels. These findings revealed the significance of apoptosis in tissue regeneration and demonstrated the potential of using apoVs to promote angiogenesis in clinical applications.

Effects of TP53 Mutations and miRs on Immune Responses in the Tumor Microenvironment Important in Pancreatic Cancer Progression

Approximately 90% of pancreatic cancers are pancreatic ductal adenocarcinomas (PDAC). PDAC is the fourth leading cause of cancer death world-wide. Therapies for PDAC are largely ineffective due to the dense desmoplastic tumor microenvironment which prevents chemotherapeutic drugs and small molecule inhibitors from exerting effective anti-cancer effects. In this review, we will discuss the roles of TP53 and miRs on the PDAC tumor microenvironment and how loss of the normal functions of TP53 promote tumor progression. The TP53 gene is mutated in approximately 50% of pancreatic cancers. Often, these TP53 mutations are point mutations which confer additional functions for the TP53 proteins. These are called gain of function (GOF) mutations (mut). Another class of TP53 mutations are deletions which result in loss of the TP53 protein; these are referred to TP53-null mutations. We have organized this review into various components/properties of the PDAC microenvironment and how they may be altered in the presence of mutant TP53 and loss of certain miR expression.

A single-sample mRNA molecular classification of bladder cancer predicting prognosis and response to immunotherapy

Background

As an immunogenic cancer, crosstalk between cancer cells and immune cells has been gradually recognized in bladder cancer (BC). Several studies have emphasized the clinical significance of the molecular stratification of BC without highlighting the role of the immune microenvironment. Although immunotherapy acted as a prospective treatment, more precise molecular stratification should be established to select those sensitive to immunotherapy.

Methods

To select specific immune genes forming subtypes indicating disparate prognoses, we performed bioinformatic analysis using BC transcriptomic profiles from six published datasets, with 408 BC samples in The Cancer Genome Atlas (TCGA) database and 295 individuals in International Cancer Genome Consortium (ICGC) database. Survival analyses were conducted using Kaplan-Meier curves, while Kruskal-Wallis tests were applied to test the differences among groups. Except for unsupervised clustering based on the differential expression of genes, we additionally performed binomial logistic regression, focusing on the mRNA level of a single sample.

Results

Unsupervised clustering showed that 4 clusters captured the best segmentation. After validation with survival data and simplification using binomial logistic regression, we found that cluster B and cluster D showed worse survival outcomes (P=0.012). Considering the similar survival outcomes of these two clusters, we recombined and performed another survival analysis, which also showed significant survival differences (P=0.0041). Bonding with clinical data, a greater proportion of risk factors were assigned to the worse prognosis subtype, especially showing higher grades in the subtype (P<0.001). In addition, immune cell infiltration, single nucleotide polymorphism (SNP) and copy number variation (CNV) all showed differences between clusters, indicating changes in the immune microenvironment and mutation burden. Through phenotypical analysis, we found metabolism and proliferation phenotypes associated with the immune clusters and mutually exclusive in BC, of which proliferation contributed to worse outcomes. Using the tumor immune dysfunction and exclusion (TIDE) score, a worse immunotherapy benefit was predicted in clusters B&D, defined as the worse prognosis subtype.

Conclusions

With this novel clustering criterion based on immune-related genes, we provide a better understanding of the immune microenvironment, further guiding the use of immunotherapy.

Passiflora mollissima Seed Extract Induced Antiproliferative and Cytotoxic Effects on CAL 27 Spheroids

Multicellular tumor spheroids are used as models in drug development due to their characteristics simulating in vivo tumors. Likewise, antiproliferative properties of extracts derived from fruits have been widely described. Peels and seeds can be used as a matrix to obtain different compounds. Recently, a study demonstrated the antiproliferative activity from a P. mollissima extract (PME) on human colon cancer cells; however, its effect on oral spheroids is unknown. Objective. To evaluate the antiproliferative potential of an extract obtained from P. mollissima seeds on the spheroid-type-3D culture model of CAL 27. Methods. CAL 27-spheroids were treated with three concentrations of PME (10, 50, and 100 μg/ml). After 72 hr incubation, morphology and cellular changes, cytotoxic and proapoptotic effect, gene expression, and metastasis were determined. Additionally, changes in the cell cycle phases responded to the PME concentrations. Comparisons between groups were made through a U Mann-Whitney test. Results. It was shown that 100 μg/ml PE affects CAL 27 cells proliferation grown in spheroids through cell cycle arrest and gene regulation of p53, HIF 1α, and CDH1. However, none of the treatments employed induced MMP9 gene expression. Conclusion. Our study shows that PME inhibits the growth and proliferation of oral tumor cells cultured in spheroids through the positive regulation of cell death and metastasis genes.

The Regulatory Network and Role of the circRNA-miRNA-mRNA ceRNA Network in the Progression and the Immune Response of Wilms Tumor Based on RNA-Seq

Circular RNA (circRNA), which is a newly discovered non-coding RNA, has been documented to play important roles in miRNA sponges, and the dysregulation of which is involved in cancer development. However, circRNA expression profiles and their role in initiation and progression of Wilms tumor (WT) remain largely unclear at present. Here, we used paired WT samples and high-throughput RNA sequencing to identify differentially expressed circRNAs (DE-circRs) and mRNAs (DE-mRs). A total of 314 DE-circRs and 1612 DE-mRs were identified. The expression of a subset of differentially expressed genes was validated by qRT–PCR. A complete circRNA-miRNA-mRNA network was then constructed based on the common miRNA targets of DE-circRs and DE-mRs identified by miRanda prediction tool. The Gene set enrichment analysis (GSEA) indicated that several signaling pathways involving targeted DE-mRs within the ceRNA network were associated with cell cycle and immune response, which implies their participation in WT development to some extent. Subsequently, these targeted DE-mRs were subjected to implement PPI analysis and to identify 10 hub genes. Four hub genes were closely related to the survival of WT patients. We then filtered prognosis-related hub genes by Cox regression and least absolute shrinkage and selection operator (LASSO) regression analysis to construct a prognosis-related risk score system based on a three-gene signature, which showed good discrimination and predictive ability for WT patient survival. Additionally, we analyzed the mutational landscape of these genes and the associations between their expression levels and those of immune checkpoint molecules and further demonstrated their potential impact on the efficacy of immunotherapy. qRT–PCR and western blotting (WB) analysis were used to validate key differentially expressed molecules at the RNA and protein levels, respectively. Besides these, we selected a key circRNA, circEYA1, for function validation. Overall, the current study presents the full-scale expression profiles of circRNAs and the circRNA-related ceRNA network in WT for the first time, deepening our understanding of the roles and downstream regulatory mechanisms of circRNAs in WT development and progression. We further constructed a useful immune-related prognostic signature, which could improve clinical outcome prediction and guide individualized treatment.

E-cigarette and food flavoring diacetyl alters airway cell morphology, inflammatory and antiviral response, and susceptibility to SARS-CoV-2

Diacetyl (DA) is an α-diketone that is used to flavor microwave popcorn, coffee, and e-cigarettes. Occupational exposure to high levels of DA causes impaired lung function and obstructive airway disease. Additionally, lower levels of DA exposure dampen host defenses in vitro. Understanding DA’s impact on lung epithelium is important for delineating exposure risk on lung health. In this study, we assessed the impact of DA on normal human bronchial epithelial cell (NHBEC) morphology, transcriptional profiles, and susceptibility to SARS-CoV-2 infection. Transcriptomic analysis demonstrated cilia dysregulation, an increase in hypoxia and sterile inflammation associated pathways, and decreased expression of interferon-stimulated genes after DA exposure. Additionally, DA exposure resulted in cilia loss and increased hyaluronan production. After SARS-CoV-2 infection, both genomic and subgenomic SARS-CoV-2 RNA were increased in DA vapor- compared to vehicle-exposed NHBECs. This work suggests that transcriptomic and physiologic changes induced by DA vapor exposure damage cilia and increase host susceptibility to SARS-CoV-2.

Echinacoside exhibits antidepressant-like effects through AMPAR-Akt/ERK-mTOR pathway stimulation and BDNF expression in mice

Background

Several natural products have been demonstrated to be effective in the treatment of depressive disorders. Echinacoside, a naturally occurring phenol extracted from Cistanche tubulosa, Echinacea angustifolia, and Cistanche spp, has a wide range of physiological effects, such as antioxidation, neuroprotection, anti-inflammatory, and immunoregulation, which are closely related to depression. In addition, echinacoside can activate protein kinase B (Akt), extracellular signal–regulated kinase (ERK), and brain-derived neurotrophic factor (BDNF) in the brain. A key downstream event of the Akt, ERK, and BDNF signaling pathways, namely mechanistic target of rapamycin (mTOR) signaling, plays a crucial role in generating an rapid antidepressant effect. Thus, echinacoside is a promising therapeutic agent for depression. However, research regarding the role of echinacoside in antidepressant effect and brain mTOR activation remains lacking.

Materials and methods

The forced swimming test and Western blot analysis in C57BL/6 mice was used to investigate the antidepressant-like activities of echinacoside and the underlying mechanism involved inα-amino3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR)–Akt/ERK–mTOR pathway.

Results

We confirmed the suggestions by previous reports that echinacoside activates Akt/ERK signaling and further demonstrated that echinacoside could provide antidepressant-like effects in mice via the activation of AMPAR–Akt/ERK–mTOR pathway in the hippocampus.

Conclusions

To the best of our knowledge, our study is the first to reveal that echinacoside is a potential treatment for depressive disorders. Moreover, the present study suggests a mechanism for the neuroprotective effect of echinacoside.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13020-021-00549-5.

Integrated Transcriptome Analysis Reveals the Impact of Photodynamic Therapy on Cerebrovascular Endothelial Cells

Blood vessels in the brain tissue form a compact vessel structure and play an essential role in maintaining the homeostasis of the neurovascular system. The low dosage of photodynamic intervention (PDT) significantly affects the expression of cellular biomarkers. To understand the impact of photodynamic interventions on cerebrovascular endothelial cells, we evaluated the dosage-dependent impact of porfimer sodium-mediated PDT on B.END3 cells using flow cytometer, comet assay, RNA sequencing, and bioinformatics analysis. To examine whether PDT can induce disorder of intracellular organelles, we did not observe any significance damage of DNA and cellular skeleton. Moreover, expression levels of cellular transporters-related genes were significantly altered, implying the drawbacks of PDT on cerebrovascular functions. To address the potential molecular mechanisms of these phenotypes, RNA sequencing and bioinformatics analysis were employed to identify critical genes and pathways among these processes. The gene ontology (GO) analysis and protein-protein interaction (PPI) identified 15 hub genes, highly associated with cellular mitosis process (CDK1, CDC20, MCM5, MCM7, MCM4, CCNA2, AURKB, KIF2C, ESPL1, BUB1B) and DNA replication (POLE2, PLOE, CDC45, CDC6). Gene set enrichment analysis (GSEA) reveals that TNF-α/NF-κB and KRAS pathways may play a critical role in regulating expression levels of transporter-related genes. To further perform qRT-PCR assays, we find that TNF-α/NF-κB and KRAS pathways were substantially up-regulated, consistent with GSEA analysis. The current findings suggested that a low dosage of PDT intervention may be detrimental to the homeostasis of blood-brain barrier (BBB) by inducing the inflammatory response and affecting the expression of surface biomarkers.

A novel role for apatinib in enhancing radiosensitivity in non-small cell lung cancer cells by suppressing the AKT and ERK pathways

Background

Radioresistance is still the major cause of radiotherapy failure and poor prognosis in patients with non-small cell lung cancer (NSCLC). Apatinib (AP) is a highly selective inhibitor of vascular endothelial growth factor receptor 2 (VEGFR2). Whether and how AP affects radiosensitivity in NSCLC remains unknown. The present study aimed to explore the radiosensitization effect of AP in NSCLC and its underlying mechanism as a radiosensitizer.

Methods

The NSCLC cell lines A549 and LK2 were treated with AP, ionizing radiation (IR), or both AP and IR. Expression of VEGFR2 was analyzed by western blot and RT-PCR. Cell proliferation was measured using CCK-8 and colony formation assays. Apoptosis and cell cycle distribution in NSCLC cells were analyzed by flow cytometry. Nuclear phosphorylated histone H2AX foci immunofluorescence staining was performed to evaluate the efficacy of the combination treatment. Western blot was used to explore the potential mechanisms of action.

Results

AP inhibited cell proliferation in a dose- and time-dependent manner. Flow cytometry analysis indicated that AP significantly increased radiation-induced apoptosis. Colony formation assays revealed that AP enhanced the radiosensitivity of NSCLC cells. AP strongly restored radiosensitivity by increasing IR-induced G2/M phase arrest. AP effectively inhibited repair of radiation-induced DNA double-strand breaks. Western blot analysis showed that AP enhanced radiosensitivity by downregulating AKT and extracellular signal-regulated kinase (ERK) signaling.

Conclusion

Our findings suggest that AP may enhance radiosensitivity in NSCLC cells by blocking AKT and ERK signaling. Therefore, AP may be a potential clinical radiotherapy synergist and a novel small-molecule radiosensitizer in NSCLC. Our study fills a gap in the field of anti-angiogenic drugs and radiosensitivity.

A Radioresponse-Related lncRNA Biomarker Signature for Risk Classification and Prognosis Prediction in Non-Small-Cell Lung Cancer

Purpose

Radiotherapy resistance is now recognized as the major obstacle to the effective therapeutic management of non-small-cell lung cancer (NSCLC). As a single biomarker has limited effect in stratifying NSCLC patients, this research aimed to identify long non-coding RNAs (lncRNAs) correlated with radiotherapy response to ameliorate forecast of NSCLC prognosis.

Methods

In a cohort of NSCLC patients with radiotherapy history (n = 96) from TCGA, genetic data of lncRNA expression profiling were performed. To identify radioresponse-related lncRNA sets which dysregulated significantly between radiosensitive (RS) and radioresistant (RR) groups, differential expression analysis was carried out. Cox relative regression was implemented to set up a radioresponse-related risk model. Moreover, we adopted survival analysis to measure the predictive potentiality of the prognosis model.

Results

Four radioresponse-related lncRNAs (CASC19, LINC01977, LINC02471, and MAGI2-AS3) were screened to create a prognostic signature. Then, we described a lncRNA signature-based regulatory network and explored the correlation of the immune microenvironment and the signature. Additionally, in vitro assays uncovered inhibition of LINC01977 weakened radioresistance of NSCLC cells.

Conclusion

We provided a novel radioresponse-related lncRNAs signature with excellent clinical potency for an effective prognostic forecast of patients.

WIP1 Inhibition by GSK2830371 Potentiates HDM201 through Enhanced p53 Phosphorylation and Activation in Liver Adenocarcinoma Cells

Simple Summary

Patients with advanced intrahepatic cholangiocarcinoma (iCCA) have a very poor prognosis, and no targeted therapy is approved for advanced iCCA. A therapeutic strategy for wild-type p53 cancers is the reactivation of p53 by inhibition of its the negative regulators, MDM2, and WIP1. In the present study, we used HDM201 (an MDM2-p53 binding antagonist) to increase p53 stabilization and upregulate the expression of downstream targets (p21 and MDM2) in RBE and SK-Hep-1 liver adenocarcinoma cell lines. The survival rate and clonogenicity decreased after HDM201 treatment in a dose-dependent manner. Combined treatment with HDM201 and GSK2830371 (WIP1 inhibitor) increased p53 phosphorylation, leading to sustained p53 activation. This combination treatment resulted in G2/M phase arrest and promoted cytotoxicity compared with MDM2 inhibitor monotherapy. Furthermore, increased expression of p53 signaling pathway target genes were identified following combination treatment with HDM201 and GSK2830371, suggesting potential roles for this combination strategy in iCCA therapy.

Abstract

Background: Intrahepatic cholangiocarcinoma (iCCA) is an adenocarcinoma arising from the intrahepatic bile duct. It is the second most common primary liver cancer and has a poor prognosis. Activation of p53 by targeting its negative regulators, MDM2 and WIP1, is a potential therapy for wild-type p53 cancers, but few reports for iCCA or liver adenocarcinoma exist. Methods: Both RBE and SK-Hep-1 liver adenocarcinoma cell lines were treated with the HDM201 (Siremadlin) MDM2-p53 binding antagonist alone or in combination with the GSK2830371 WIP1 phosphatase inhibitor. Cell proliferation, clonogenicity, protein and mRNA expression, cell cycle distribution, and RNA sequencing were performed to investigate the effect and mechanism of this combination. Results: GSK2830371 alone demonstrated minimal activity on proliferation and colony formation, but potentiated growth inhibition (two-fold decrease in GI₅₀) and cytotoxicity (four-fold decrease in IC₅₀) by HDM201 on RBE and SK-Hep-1 cells. HDM201 increased p53 protein expression, leading to transactivation of downstream targets (p21 and MDM2). Combination with GSK2830371 increased p53 phosphorylation, resulting in an increase in both p53 accumulation and p53-dependent trans-activation. G2/M arrest was observed by flow cytometry after this treatment combination. RNA sequencing identified 21 significantly up-regulated genes and five downregulated genes following p53 reactivation by HDM201 in combination with GSK2830371 at 6 h and 24 h time points compared with untreated controls. These genes were predominantly known transcriptional targets regulated by the p53 signaling pathway, indicating enhanced p53 activation as the predominant effect of this combination. Conclusion: The current study demonstrated that GSK2830371 enhanced the p53-dependent antiproliferative and cytotoxic effect of HDM201 on RBE and SK-Hep-1 cells, providing a novel strategy for potentiating the efficacy of targeting the p53 pathway in iCCA.

PHLDA3 exerts an antitumor function in prostate cancer by down-regulating Wnt/β-catenin pathway via inhibition of Akt

Pleckstrin homology-like domain family A, member 3 (PHLDA3) is a novel tumor-related protein that mediates carcinogenesis of multiple cancers. However, the relevance of PHLDA3 in prostate cancer has not been explored. The purpose of this work was to illustrate the possible roles and mechanisms of PHLDA3 in prostate cancer. Our data showed strikingly lower abundance of PHLDA3 in prostate cancer, and that low levels of PHLDA3 in prostate cancer patients was associated with reduced survival. PHLDA3 was also weakly expressed in prostate cancer cells, and demethylation treatment dramatically up-regulated the expression level of PHLDA3. Up-regulation of PHLDA3 restrained proliferation, induced G1 cell cycle arrest, suppressed epithelial-mesenchymal transition of prostate cancer cells. In addition, up-regulation of PHLDA3 increased the sensitivity of prostate cancer cells to docetaxel In-depth research into the mechanism elucidated that PHLDA3 overexpression decreased the phosphorylation of Akt and suppressed the activation of Wnt/β-catenin signaling. Overexpression of constitutively active Akt strikingly abolished PHLDA3-mediated inactivation of Wnt/β-catenin pathway. A xenograft assay revealed that prostate cancer cells with PHLDA3 overexpression displayed reduced tumorigenicity in vivo. Collectively, these data document that PHLDA3 exerts an outstanding cancer-inhibiting role in prostate cancer by down-regulating Wnt/β-catenin pathway via the inhibition of Akt. This work highlights PHLDA3 as a novel anticancer target for prostate cancer.

Replication catastrophe induced by cyclic hypoxia leads to increased APOBEC3B activity

Tumor heterogeneity includes variable and fluctuating oxygen concentrations, which result in the accumulation of hypoxic regions in most solid tumors. Tumor hypoxia leads to increased therapy resistance and has been linked to genomic instability. Here, we tested the hypothesis that exposure to levels of hypoxia that cause replication stress could increase APOBEC activity and the accumulation of APOBEC-mediated mutations. APOBEC-dependent mutational signatures have been well-characterized, although the physiological conditions which underpin them have not been described. We demonstrate that fluctuating/cyclic hypoxic conditions which lead to replication catastrophe induce the expression and activity of APOBEC3B. In contrast, stable/chronic hypoxic conditions which induce replication stress in the absence of DNA damage are not sufficient to induce APOBEC3B. Most importantly, the number of APOBEC-mediated mutations in patient tumors correlated with a hypoxia signature. Together, our data support the conclusion that hypoxia-induced replication catastrophe drives genomic instability in tumors, specifically through increasing the activity of APOBEC3B.

Hypoxia-induced SETX links replication stress with the unfolded protein response

Tumour hypoxia is associated with poor patient prognosis and therapy resistance. A unique transcriptional response is initiated by hypoxia which includes the rapid activation of numerous transcription factors in a background of reduced global transcription. Here, we show that the biological response to hypoxia includes the accumulation of R-loops and the induction of the RNA/DNA helicase SETX. In the absence of hypoxia-induced SETX, R-loop levels increase, DNA damage accumulates, and DNA replication rates decrease. Therefore, suggesting that, SETX plays a role in protecting cells from DNA damage induced during transcription in hypoxia. Importantly, we propose that the mechanism of SETX induction in hypoxia is reliant on the PERK/ATF4 arm of the unfolded protein response. These data not only highlight the unique cellular response to hypoxia, which includes both a replication stress-dependent DNA damage response and an unfolded protein response but uncover a novel link between these two distinct pathways.

Autophagy Modulators in Cancer Therapy

Autophagy is a process of self-degradation that plays an important role in removing damaged proteins, organelles or cellular fragments from the cell. Under stressful conditions such as hypoxia, nutrient deficiency or chemotherapy, this process can also become the strategy for cell survival. Autophagy can be nonselective or selective in removing specific organelles, ribosomes, and protein aggregates, although the complete mechanisms that regulate aspects of selective autophagy are not fully understood. This review summarizes the most recent research into understanding the different types and mechanisms of autophagy. The relationship between apoptosis and autophagy on the level of molecular regulation of the expression of selected proteins such as p53, Bcl-2/Beclin 1, p62, Atg proteins, and caspases was discussed. Intensive studies have revealed a whole range of novel compounds with an anticancer activity that inhibit or activate regulatory pathways involved in autophagy. We focused on the presentation of compounds strongly affecting the autophagy process, with particular emphasis on those that are undergoing clinical and preclinical cancer research. Moreover, the target points, adverse effects and therapeutic schemes of autophagy inhibitors and activators are presented.

Hypoxia and Extracellular Acidification as Drivers of Melanoma Progression and Drug Resistance

Hypoxia and elevated extracellular acidification are prevalent features of solid tumors and they are often shown to facilitate cancer progression and drug resistance. In this review, we have compiled recent and most relevant research pertaining to the role of hypoxia and acidification in melanoma growth, invasiveness, and response to therapy. Melanoma represents a highly aggressive and heterogeneous type of skin cancer. Currently employed treatments, including BRAF V600E inhibitors and immune therapy, often are not effective due to a rapidly developing drug resistance. A variety of intracellular mechanisms impeding the treatment were discovered. However, the tumor microenvironment encompassing stromal and immune cells, extracellular matrix, and physicochemical conditions such as oxygen level or acidity, may also influence the therapy effectiveness. Hypoxia and acidification are able to reprogram the metabolism of melanoma cells, enhance their survival and invasiveness, as well as promote the immunosuppressive environment. For this reason, these physicochemical features of the melanoma niche and signaling pathways related to them emerge as potential therapeutic targets.

Ginkgolide B Maintains Calcium Homeostasis in Hypoxic Hippocampal Neurons by Inhibiting Calcium Influx and Intracellular Calcium Release

Ginkgolide B (GB), a terpene lactone and active ingredient of Ginkgo biloba, shows protective effects in neuronal cells subjected to hypoxia. We investigated whether GB might protect neurons from hypoxic injury through regulation of neuronal Ca²⁺ homeostasis. Primary hippocampal neurons subjected to chemical hypoxia (0.7 mM CoCl₂) in vitro exhibited an increase in cytoplasmic Ca²⁺ (measured from the fluorescence of fluo-4), but this effect was significantly diminished by pre-treatment with 0.4 mM GB. Electrophysiological recordings from the brain slices of rats exposed to hypoxia in vivo revealed increases in spontaneous discharge frequency, action potential frequency and calcium current magnitude, and all these effects of hypoxia were suppressed by pre-treatment with 12 mg/kg GB. Western blot analysis demonstrated that hypoxia was associated with enhanced mRNA and protein expressions of Ca_v1.2 (a voltage-gated Ca²⁺ channel), STIM1 (a regulator of store-operated Ca²⁺ entry) and RyR2 (isoforms of Ryanodine Receptor which mediates sarcoplasmic reticulum Ca²⁺ release), and these actions of hypoxia were suppressed by GB. Taken together, our in vitro and in vivo data suggest that GB might protect neurons from hypoxia, in part, by regulating Ca²⁺ influx and intracellular Ca²⁺ release to maintain Ca²⁺ homeostasis.

KANK family proteins in cancer

The Kank (kidney or KN motif and ankyrin repeat domain-containing) family of proteins has been described as essential for crosstalk between actin and microtubules. Kank1, 2, 3 and 4 arose by gene duplication and diversification and share conserved structural domains. KANK proteins are localised mainly to the plasma membrane in focal adhesions, indirectly affecting RhoA and Rac1 thus regulating actin cytoskeleton. In addition, Kank proteins are part of the cortical microtubule stabilisation complex regulating microtubules. Most of the data have been collected for Kank1 protein whose expression promotes apoptosis and cell-cycle arrest while Kank3 was identified as hypoxia-inducible proapoptotic target of p53. A discrepancy in Kanks role in regulation of cell migration and sensitivity to antitumour drugs has been observed in different cell models. Since expression of Kank1 and 3 correlate positively with tumour progression and patient outcome, at least in some tumour types, they are candidates for tumour suppressors.

Oxygen regulation of TET enzymes

Hypoxia has a significant impact on many physiological and pathological processes. Over the recent years, its role in modulation of epigenetic remodelling has also become clearer. In cancer, low oxygen environments and aberrant epigenomes often go hand in hand, and changes in DNA methylation are now commonly recognised as potential outcome indicators. TET (ten-eleven translocation) family enzymes are alpha-ketoglutarate-, iron- and oxygen-dependent DNA demethylases and are key players in these processes. Although TETs have historically been considered tumour suppressors, recent studies suggest that their functions in cancer might not be straightforward. Recently, inhibition of TETs has been reported to have positive impact in cancer immunotherapy and vaccination studies. This underlines the current interest in developing targeted pharmaceutical inhibitors of these enzymes. Here, we will survey the complexity of TET roles in cancer, and its hypoxic modulation, as well as highlight the potential of these enzymes as therapeutic targets.

Metabolome-Driven Regulation of Adenovirus-Induced Cell Death

A viral infection that involves virus invasion, protein synthesis, and virion assembly is typically accompanied by sharp fluctuations in the intracellular levels of metabolites. Under certain conditions, dramatic metabolic shifts can result in various types of cell death. Here, we review different types of adenovirus-induced cell death associated with changes in metabolic profiles of the infected cells. As evidenced by experimental data, in most cases changes in the metabolome precede cell death rather than represent its consequence. In our previous study, the induction of autophagic cell death was observed following adenovirus-mediated lactate production, acetyl-CoA accumulation, and ATP release, while apoptosis was demonstrated to be modulated by alterations in acetate and asparagine metabolism. On the other hand, adenovirus-induced ROS production and ATP depletion were demonstrated to play a significant role in the process of necrotic cell death. Interestingly, the accumulation of ceramide compounds was found to contribute to the induction of all the three types of cell death mentioned above. Eventually, the characterization of metabolite analysis could help in uncovering the molecular mechanism of adenovirus-mediated cell death induction and contribute to the development of efficacious oncolytic adenoviral vectors.

Proliferation, migration and invasion of triple negative breast cancer cells are suppressed by berbamine via the PI3K/Akt/MDM2/p53 and PI3K/Akt/mTOR signaling pathways

Breast cancer is the second most common cause of cancer-associated mortality among women worldwide, and triple negative breast cancer (TNBC) is the most aggressive subtype of breast cancer. Berbamine (BBM) is a traditional Chinese medicine used for the treatment of leukopenia without any obvious side effects. Recent reports found that BBM has anti-cancer effects. The present study aimed to investigate the effects of BBM on TNBC cell lines and the underlying molecular mechanism. MDA-MB-231 cells and MCF-7 cells, two TNBC cell lines, were treated with various concentrations of BBM. A series of bioassays including MTT, colony formation, EdU staining, apoptosis, trypan blue dye, wound healing, transwell, ELISA and western blotting assays were performed. The results showed that BBM significantly inhibited cell proliferation of MDA-MB-231 cells (P<0.05; IC₅₀=22.72 µM) and MCF-7 cells (P<0.05; IC₅₀=20.92 µM). BBM (20 µM) decreased the apoptosis ratio (percentage of absorbance compared with the control group) by 28.4±3.3% (P<0.05) in MDA-MB-231 cells, and 62.4±24.6% (P<0.05) in MCF-7 cells. In addition, BBM inhibited cell migration and invasion of TNBC cells. Furthermore, the expression levels of PI3K, phosphorylated-Akt/Akt, COX-2, LOX, MDM2 and mTOR were downregulated by BBM, and the expression of p53 was upregulated by BBM. These results indicated that BBM may suppress the development of TNBC via regulation of the PI3K/Akt/MDM2/p53 and PI3K/Akt/mTOR signal pathways. Therefore, BBM might be used as a drug candidate for the treatment of TNBC in the future.

The role of cell signaling in the crosstalk between autophagy and apoptosis in the regulation of tumor cell survival in response to sorafenib and neratinib

The molecular mechanisms by which tumor cells survive or die following therapeutic interventions are complex. There are three broadly defined categories of cell death processes: apoptosis (Type I), autophagic cell death (Type II), and necrosis (Type III). In hematopoietic tumor cells, the majority of toxic stimuli cause these cells to undergo a death process called apoptosis; apoptosis specifically involves the cleavage of DNA into large defined pieces and their subsequent localization in vesicles. Thus, 'pure' apoptosis largely lacks inflammatory potential. In carcinomas, however, the mechanisms by which tumor cells ultimately die are considerably more complex. Although the machinery of apoptosis is engaged by toxic stimuli, other processes such as autophagy ("self-eating") and replicative cell death can lead to observations that do not simplistically correspond to any of the individual Type I-III formalized death categories. The 'hybrid' forms of cell death observed in carcinoma cells result in cellular materials being released into the extracellular space without packaging, which promotes inflammation, potentially leading to the accelerated re-growth of surviving tumor cells by macrophages. Drugs as single agents or in combinations can simultaneously initiate signaling via both apoptotic and autophagic pathways. Based on the tumor type and its oncogene drivers, as well as the drug(s) being used and the duration and intensity of the autophagosome signal, apoptosis and autophagy have the potential to act in concert to kill or alternatively that the actions of either pathway can act to suppress signaling by the other pathway. And, there also is evidence that autophagic flux, by causing lysosomal protease activation, with their subsequent release into the cytosol, can directly mediate killing. This review will discuss the interactive biology between apoptosis and autophagy in carcinoma cells. Finally, the molecular actions of the FDA-approved drugs neratinib and sorafenib, and how they enhance both apoptotic and toxic autophagic processes, alone or in combination with other agents, is discussed in a bench-to-bedside manner.

Three dimensional engineered models to study hypoxia biology in breast cancer

Breast cancer is the second leading cause of mortality among women worldwide. Despite the available therapeutic regimes, variable treatment response is reported among different breast cancer subtypes. Recently, the effects of the tumor microenvironment on tumor progression as well as treatment responses have been widely recognized. Hypoxia and hypoxia inducible factors in the tumor microenvironment have long been known as major players in tumor progression and survival. However, the majority of our understanding of hypoxia biology has been derived from two dimensional (2D) models. Although many hypoxia-targeted therapies have elicited promising results in vitro and in vivo, these results have not been successfully translated into clinical trials. These limitations of 2D models underscore the need to develop and integrate three dimensional (3D) models that recapitulate the complex tumor-stroma interactions in vivo. This review summarizes role of hypoxia in various hallmarks of cancer progression. We then compare traditional 2D experimental systems with novel 3D tissue-engineered models giving accounts of different bioengineering platforms available to develop 3D models and how these 3D models are being exploited to understand the role of hypoxia in breast cancer progression.

Protein acetylation and deacetylation: An important regulatory modification in gene transcription (Review)

Cells primarily rely on proteins to perform the majority of their physiological functions, and the function of proteins is regulated by post-translational modifications (PTMs). The acetylation of proteins is a dynamic and highly specific PTM, which has an important influence on the functions of proteins, such as gene transcription and signal transduction. The acetylation of proteins is primarily dependent on lysine acetyltransferases and lysine deacetylases. In recent years, due to the widespread use of mass spectrometry and the emergence of new technologies, such as protein chips, studies on protein acetylation have been further developed. Compared with histone acetylation, acetylation of non-histone proteins has gradually become the focus of research due to its important regulatory mechanisms and wide range of applications. The discovery of specific protein acetylation sites using bioinformatic tools can greatly aid the understanding of the underlying mechanisms of protein acetylation involved in related physiological and pathological processes.

Icariside II protects cardiomyocytes from hypoxia‑induced injury by upregulating the miR‑7‑5p/BTG2 axis and activating the PI3K/Akt signaling pathway

Icariside II (ICS II) has been reported to have protective effects against oxidative stress. However, whether ICS II protects cardiomyocytes from myocardial infarction (MI), and the associated underlying mechanisms, remain to be elucidated. Therefore, the current study investigated the effects of ICS II on hypoxia‑injured H9c2 cells, as well as the associated molecular mechanisms. A hypoxic injury model was established to emulate the effects of MI. The effects of ICS II on the proliferation of rat cardiomyocyte H9c2 cells were assessed with cell counting kit‑8 assays. The apoptotic status of the cells was assessed by flow cytometry, and the expression of apoptosis‑related proteins was analyzed by western blotting. A microRNA (miRNA/miR) microarray was used to quantify the differential expression of miRNAs after ICS II treatment, and the levels of miR‑7‑5p were further quantified by reverse transcription‑quantitative PCR. Whether ICS II affected hypoxia‑injured cells via miR‑7‑5p was subsequently examined, and the target of miR‑7‑5p was also investigated by bioinformatics analysis and luciferase reporter assays. The effects of ICS II on the PI3K/Akt pathway were then evaluated by western blot analysis. Hypoxia treatment decreased viability and the migration and invasion abilities of H9c2 cells, and also induced apoptosis. ICS II significantly increased viability and reduced hypoxia‑associated apoptosis. Moreover, ICS II treatment led to the upregulation of miR‑7‑5p, and the protective effects of ICS II were found to rely on miR‑7‑5p. Moreover, BTG anti‑proliferation factor (BTG2) was identified as a direct target of miR‑7‑5p, and overexpression of BTG2 inhibited the protective effects of miR‑7‑5p. Finally, ICS II treatment resulted in the activation of the PI3K/Akt signaling pathway, which is essential for the survival of H9c2 cells under hypoxic conditions. In summary, ICS II reduces hypoxic injury in H9c2 cells via the miR‑7‑5p/BTG2 axis and activation of the PI3K/Akt signaling pathway.

ABHD4-dependent developmental anoikis safeguards the embryonic brain

A specialized neurogenic niche along the ventricles accumulates millions of progenitor cells in the developing brain. After mitosis, fate-committed daughter cells delaminate from this germinative zone. Considering the high number of cell divisions and delaminations taking place during embryonic development, brain malformations caused by ectopic proliferation of misplaced progenitor cells are relatively rare. Here, we report that a process we term developmental anoikis distinguishes the pathological detachment of progenitor cells from the normal delamination of daughter neuroblasts in the developing mouse neocortex. We identify the endocannabinoid-metabolizing enzyme abhydrolase domain containing 4 (ABHD4) as an essential mediator for the elimination of pathologically detached cells. Consequently, rapid ABHD4 downregulation is necessary for delaminated daughter neuroblasts to escape from anoikis. Moreover, ABHD4 is required for fetal alcohol-induced apoptosis, but not for the well-established form of developmentally controlled programmed cell death. These results suggest that ABHD4-mediated developmental anoikis specifically protects the embryonic brain from the consequences of sporadic delamination errors and teratogenic insults.

AKT inhibition as a strategy for targeting hypoxic HPV-positive HNSCC

BACKGROUND AND PURPOSE

Hypoxia negatively affects treatment outcome in both Human papillomavirus (HPV)-positive and -negative head and neck squamous cell carcinomas (HNSCC). Despite HPV-positive patients having a relatively good prognosis, hypoxic HPV-positive tumours are associated with poor treatment outcome, and do not respond to hypoxia modification. Earlier, we showed that hypoxia induces the pro-survival AKT pathway. In this study, we aim to investigate whether AKT inhibition affects the response to radiotherapy under hypoxia, and determine whether this is a viable treatment strategy for HNSCC patients with hypoxic HPV-positive tumours.

MATERIALS AND METHODS

Nine HPV-negative and 4 HPV-positive HNSCC cell lines were characterized. AKT activation was assessed by western blot. Survival in response to hypoxic incubation, AKT inhibition and/or irradiation was assessed using CCK8 assays and colony forming assays.

RESULTS

AKT was activated under hypoxia in both HPV-negative and -positive cell lines, which could be abrogated by the AKT inhibitor MK2206. HPV-positive cell lines were highly sensitive to MK2206 at normoxia. In all HNSCC cell lines, AKT inhibition was significantly more effective in inhibiting cell growth during hypoxic conditions than under normoxia. Hypoxia significantly reduced radiosensitivity irrespective of HPV-status, yet specifically in HPV-positive cells this could be efficiently reversed by AKT inhibition.

CONCLUSIONS

These data suggest that HNSCC tumours are dependent on AKT to survive hypoxia, and that AKT inhibition is specifically effective in radioresistant hypoxic HPV-positive cells. Targeting AKT may thus be a potential way to overcome hypoxia induced radioresistance, particularly in HPV-positive HNSCC tumours.

Characteristics of Circular RNA Expression Profiles of Porcine Granulosa Cells in Healthy and Atretic Antral Follicles

Circular RNAs (circRNAs) are thought to play essential roles in multiple biological processes, including apoptosis, an important process in antral follicle atresia. We aimed to investigate the potential involvement of circRNAs in granulosa cell apoptosis and thus antral follicle atresia. CircRNA expression profiles were generated from porcine granulosa cells isolated from healthy antral (HA) and atretic antral (AA) follicles. Over 9632 circRNAs were identified, of which 62 circRNAs were differentially expressed (DE-circRNAs). Back-splicing, RNase R resistance, and stability of DE-circRNAs were validated, and miRNA binding sites and related target genes were predicted. Two exonic circRNAs with low false discovery rate (FDR) high fold change, miRNA binding sites, and relevant biological functions—circ_CBFA2T2 and circ_KIF16B—were selected for further characterization. qRT-PCR and linear regression analysis confirmed expression and correlation of the targeted genes—the antioxidant gene GCLC (potential target of circ_CBFA2T2) and the apoptotic gene TP53 (potential target of circ_KIF16B). Increased mRNA content of TP53 in granulosa cells of AA follicles was further confirmed by strong immunostaining of both p53 and its downstream target pleckstrin homology like domain family a member 3 (PHLDA3) in AA follicles compared to negligible staining in granulosa cells of HA follicles. Therefore, we concluded that aberrantly expressed circRNAs presumably play a potential role in antral follicular atresia.

Tanshinone IIA Ameliorates Progression of CAD Through Regulating Cardiac H9c2 Cells Proliferation and Apoptosis by miR-133a-3p/EGFR Axis

Background

Coronary artery disease (CAD) leads to the highest mortality worldwide, seriously threatening human health. Tanshinone IIA (Tan IIA), which could be extracted from Danshen, is applied in the treatment of cardiovascular and cerebrovascular diseases. MicroRNAs (miRNAs, miRs) play pivotal roles in cell proliferation and cell apoptosis of the cardiovascular system. The aim of the present study was to explore the role of Tan IIA in CAD in vitro and the underlying molecular mechanism.

Methods

Real-time polymerase chain reaction (RT-PCR) and Western blot were used for the detection of miRNA/mRNA and protein, respectively. Target genes of miR-133a-3p were searched in TargetScan, and the targeting relationship was verified by dual-luciferase reporter assay. Cell proliferation was determined using a Cell Counting Kit-8 (CCK-8) and EdU labeling. Cell apoptosis was detected by flow cytometry and TUNEL staining.

Results

In the present study, lower miR-133a-3p level and higher epidermal growth factor receptor (EGFR; the target of miR-133a-3p) level were found in H₂O₂-induced H9c2 cells. In addition, Tan IIA upregulated miR-133a-3p and downregulated EGFR expression. Moreover, Tan IIA promoted cell proliferation and suppressed apoptosis and enhanced G0/G1, which was reversed by miR-133a-3p inhibitor, while siRNA-EGFR abolished the effects induced by miR-133a-3p in H₂O₂-induced H9c2 cells.

Conclusion

Tan IIA reversed H₂O₂-induced cell proliferation reduction, cell apoptosis induction, and G0/G1 arrest reduction in H9c2 cells by miR-133a-3p/EGFR axis. The findings suggested a potential molecular basis of Tan IIA in treating patients with CAD.

Oxygen-releasing manganese clay hybrid complex triggers p53-mediated cancer cell death in hypoxia

Hypoxia in tumor microenvironment is responsible for resistance to conventional modes of cancer therapeutics. A manganese-clay hybrid compound MHC was shown to generate molecular oxygen in aqueous solution. In this study we have shown that MHC, in hypoxia, causes cancer cell death, through release of molecular oxygen and via p53-dependent apoptosis. MHC treatment of cells results in depletion of mitochondrial membrane potential and inhibition of ROS production, in a cell-specific manner. In hypoxia, the oxygen from MHC releases cells from S-phase arrest thus causing p53-dependent apoptosis. The induction of apoptosis by MHC is higher in p53 Wt/Wt cells when it is compared with p53 Mt/Mt cells. The released oxygen from MHC triggers apoptosis via p53 activation through its enhanced homo-oligomerization, post-translational modifications and nuclear localization. Thus MHC as a cellular oxygen-releasing compound has high potential as a drug for hypoxic tumor regression.

The effect of ibrutinib on radiosensitivity in pancreatic cancer cells by targeting EGFR/AKT/mTOR signaling pathway

Radiotherapy is an effective treatment for pancreatic cancer. However, radio-resistance often resulted in poor prognostic. Ibrutinib is an orally small molecule drug in B cell malignancies. Here, we investigated for the first time the effect of ibrutinib on radio-sensitivity of human pancreatic cancer cells in vitro and the potential mechanism involved in it. Human BXPC3 and Capan2 cell lines were treated with ibrutinib, and cell viability was conducted with CCK-8 assay. Cell clone formation was observed after treated with ibrutinib and (or) radiation by clone formation assay. The cell cycle and cell apoptosis were measured by flow cytometry. Protein levels was analyzed by western blot. The results revealed that ibrutinib inhibited the proliferation of pancreatic cancer cells. Ibrutinib enhanced the effect of radiation with a sensitization enhancement ratio (SER) of 1.34, 1.68 in BXPC3 and Capan2 cells respectively. Ibrutinib combined with radiation induced G2/M arrest and cell apoptosis. Further investigations revealed that ibrutinib decreased the phosphorylation of EGFR, then reversed the upregulation of p-AKT and downstream genes by radiation. In conclusion, these results suggested that ibrutinib might be an excellent radiosensitizer in pancreatic cancer.