Behavior Of Tumor Cells Research Articles

Long noncoding RNA DLEU2 regulates the progression of Wilm's tumor via miR-539-3p/HOXB2 axis

Wilm's tumor is the most common renal cancer in the pediatric age group. Long noncoding RNAs (lncRNAs) are a kind of RNA transcripts longer than ∼200 nucleotides, which have been revealed to be involved in the progression of Wilm's tumor. The purpose of this study was to investigate the function and molecular mechanism of deleted in lymphocytic leukemia 2 (DLEU2) lncRNA in Wilm's tumor progression. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression of DLEU2, miR-539-3p and HOXB2 mRNA in Wilm's tumor tissues and cells. Cell counting kit-8 assay, 5-ethynyl-2'-deoxyuridine (EdU) assay, colony formation assay, transwell assay, and flow cytometry were applied to explore the function of DLEU2 in Wilm's tumor cell malignant phenotypes and the regulatory mechanism among DLEU2, miR-539-3p and HOXB2 in Wilm's tumor cells. Western blot examined the protein levels of Bax, Bcl-2 and HOXB2. The relationship between miR-539-3p and DLEU2 or HOXB2 was verified by dual-luciferase reporter assay. Xenograft models of Wilm's tumor were established to study the role of DLEU2 invivo. DLEU2 and HOXB2 were significantly highly expressed in primary Wilm's tumor tissues and invitro cell lines. Silencing of DLEU2 reduced the proliferation, migration and invasion of Wilm's tumor cells, and promoted cell apoptosis. MiR-539-3p was confirmed to be a target of DLEU2. DLEU2 silencing inhibited the malignant behaviors of Wilm's tumor cells by releasing miR-539-3p. In addition, HOXB2 was a target of miR-539-3p. Overexpression of HOXB2 partially restored the inhibitory effects of miR-539-3p on Wilm's tumor cell malignant behaviors. Animal experiments also confirmed the anti-tumor effects of DLEU2 silencing invivo. DLEU2 up-regulates the expression of HOXB2 by targetedly repressing miR-539-3p, thereby at least partially promoting the development of Wilm's tumor, these findings provided novel therapeutic targets for Wilm's tumor.

Overexpression of NNMT in Glioma Aggravates Tumor Cell Progression: An Emerging Therapeutic Target

Simple SummaryGlioma is one of the most common intracranial malignancies and is incurable due to strong aggressiveness and resistance to radiotherapy and chemotherapy. The lack of effective therapeutic targets is a major problem in current treatment. In the present study, we found that nicotinamide N-methyltransferase (NNMT) is a key factor influencing the occurrence and development of glioma. High NNMT expression in glioma is a predictor of short overall survival and poor patient outcome. NNMT knockdown reduced the volume of mice xenograft glioma and the viability of glioma cells. Additionally, overexpression of NNMT epigenetically silenced GAP43 through DNA methylation, histone methylation, and deacetylation modification processes. GAP43 can inhibit the formation of microtubules in tumor and intertumor cell network connections and induce apoptosis through the SIRT1 signaling pathway. Therefore, NNMT could be a potential candidate for the clinical diagnosis and treatment of glioma.Purpose: Increasing evidence has revealed that nicotinamide N-methyltransferase (NNMT) is a key factor influencing the prognosis of tumors. The present study aimed to investigate the role of NNMT in glioma and to elucidate the associated functional mechanisms. Methods: Clinical samples were analyzed by immunohistochemical staining and Western blotting to evaluate NNMT expression in glioma and normal brain tissues. The correlation between NNMT expression and glioma was analyzed using the Cancer Genome Atlas (TCGA) database. Additionally, NNMT was knocked down in two types of glioma cells, U87 and U251, to evaluate the invasive ability of these cells. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to validate NNMT knockdown in the cells. Furthermore, ELISA was used to determine the balance between nicotinamide adenine dinucleotide and nicotinamide adenine dinucleotide hydrogen (NAD/NADH ratio), which verified the altered methylation patterns in the cells. The glioma xenograft mouse models were used to verify the regulatory role of NNMT, GAP43, and SIRT1. Results: Analysis based on our clinical glioma samples and TCGA database revealed that overexpression of NNMT was associated with poor prognosis of patients. Knockdown of NNMT reduced the invasive ability of glioma cells, and downregulation of its downstream protein GAP43 occurred due to altered cellular methylation caused by NNMT overexpression. Gene Set Enrichment Analysis confirmed that NNMT modulated the NAD-related signaling pathway and showed a negative association between NNMT and SIRT1. Moreover, the regulatory roles of NNMT, GAP43, and SIRT1 were confirmed in glioma xenograft mouse models. Conclusion: Overexpression of NNMT causes abnormal DNA methylation through regulation of the NAD/NADH ratio, which in turn leads to the downregulation of GAP43 and SIRT1, eventually altering the biological behavior of tumor cells.

A thermo-sensitive hydrogel composed of methylcellulose/hyaluronic acid/silk fibrin as a biomimetic extracellular matrix to simulate breast cancer malignancy

The development of three-dimensional (3D) culture models is promising for cancer biology studies and the discovery of new anticancer drugs because they mimic the in vivo situation better without the need for animal facilities. To reach a 3D culture matrix, we developed a temperature-sensitive hydrogel inspired by the native tumor biology approach. Hence, methylcellulose (MC), hyaluronic acid (HA), and silk fibroin (SF) were combined to mimic the native extracellular matrix. The obtained MCHASF hydrogel was physicochemically characterized and exhibited a similar stiffness to native breast tumors, showing in vitro stability for up to 6 weeks, a non-homogeneous surface, and high pore interconnectivity characters. Human breast cancer cells (MDA-MB-231) cultured in hydrogel were morphologically assessed and showed irregular cytoskeleton shapes and actin-based protrusions characteristic of their malignancy. In addition, the cells displayed a higher cell migration rate and up-regulated expression of vascular endothelial growth factor (VEGF) and matrix metalloproteinase (MMP2, MMP9) and resistance to chemotherapy than two-dimensional (2D) cultures, which demonstrates this 3D environment enhanced metastatic potential. Overall, this novel 3D in vitro model can offer an insight into investigating different features of tumor cell behavior, including metastasis and drug response.

Editor's Note: Identification of Src-Specific Phosphorylation Site on Focal Adhesion Kinase: Dissection of the Role of Src SH2 and Catalytic Functions and Their Consequences for Tumor Cell Behavior

The editors are publishing this note to alert readers to concerns about this article (1). We were informed by the authors that in Fig. 6A, the same image showing phospho-FAK tyr-925 staining was used in error in both Fig. 6M (Vector) and Fig. 6P (SrcMF).

TM4SF1 promotes esophageal squamous cell carcinoma metastasis by interacting with integrin α6

Transmembrane-4 L-six family member-1 (TM4SF1) is a member of the L6 family and functions as a signal transducer to regulate tumor cell behaviors. However, the function and mechanism of TM4SF1 in esophageal squamous cell carcinoma (ESCC) metastasis remains unclear. Here, we find that TM4SF1 expression is increased and positively correlated with clinical TNM stage, N classification, differentiation, tumor size, and poor prognosis in ESCC patients. Interestingly, we demonstrate that TM4SF1 promotes ESCC cell adhesion, spreading, migration, and invasion, but not cell proliferation, in a laminin-dependent manner by interacting with integrin α6. Mechanistically, the TM4SF1/integrin α6/FAK axis signal pathway mediates cell migration under laminin-coating condition. Inhibiting FAK or knocking down TM4SF1 can attenuate TM4SF1-mediated cell migration and lung metastasis. Clinically, the TM4SF1/integrin α6/FAK axis positively correlates with ESCC. Altogether, these findings reveal a new mechanism of TM4SF1 in promoting ESCC metastasis via binding to integrin α6 and suggest that the cross-talk between TM4SF1 and integrin α6 may serve as a therapeutic target for ESCC.

Optical Cellular Micromotion: A New Paradigm to Measure Tumor Cells Invasion within Gels Mimicking the 3D Tumor Environments.

Measuring tumor cell invasiveness through 3D tissues, particularly at the single-cell level, can provide important mechanistic understanding and assist in identifying therapeutic targets of tumor invasion. However, current experimental approaches, including standard in vitro invasion assays, have limited physiological relevance and offer insufficient insight into the vast heterogeneity in tumor cell migration through tissues. To address these issues, here the concept of optical cellular micromotion is reported on, where digital holographic microscopy is used to map the optical nano- to submicrometer thickness fluctuations within single-cells. These fluctuations are driven by the dynamic movement of subcellular structures including the cytoskeleton and inherently associated with the biological processes involved in cell invasion within tissues. It is experimentally demonstrated that the optical cellular micromotion correlates with tumor cells motility and invasiveness both at the population and single-cell levels. In addition, the optical cellular micromotion significantly reduced upon treatment with migrastatic drugs that inhibit tumor cell invasion. These results demonstrate that micromotion measurements can rapidly and non-invasively determine the invasive behavior of single tumor cells within tissues, yielding a new and powerful tool to assess the efficacy of approaches targeting tumor cell invasiveness.

Small Molecule Inhibitors in Adult High-Grade Glioma: From the Past to the Future.

Glioblastoma is the most common primary malignant tumor in the brain and has a dismal prognosis despite patients accepting standard therapies. Alternation of genes and deregulation of proteins, such as receptor tyrosine kinase, PI3K/Akt, PKC, Ras/Raf/MEK, histone deacetylases, poly (ADP-ribose) polymerase (PARP), CDK4/6, branched-chain amino acid transaminase 1 (BCAT1), and Isocitrate dehydrogenase (IDH), play pivotal roles in the pathogenesis and progression of glioma. Simultaneously, the abnormalities change the cellular biological behavior and microenvironment of tumor cells. The differences between tumor cells and normal tissue become the vulnerability of tumor, which can be taken advantage of using targeted therapies. Small molecule inhibitors, as an important part of modern treatment for cancers, have shown significant efficacy in hematologic cancers and some solid tumors. To date, in glioblastoma, there have been more than 200 clinical trials completed or ongoing in which trial designers used small molecules as monotherapy or combination regimens to correct the abnormalities. In this review, we summarize the dysfunctional molecular mechanisms and highlight the outcomes of relevant clinical trials associated with small-molecule targeted therapies. Based on the outcomes, the main findings were that small-molecule inhibitors did not bring more benefit to newly diagnosed glioblastoma, but the clinical studies involving progressive glioblastoma usually claimed “noninferiority” compared with historical results. However, as to the clinical inferiority trial, similar dosing regimens should be avoided in future clinical trials.

Abstract 6289: Activated neutrophils induce robust mesenchymal migration of gastric cancer cells

Abstract Background: Activated neutrophils can produce multiple substances including various enzymes such as neutrophil elastase, myeloperoxidase, as well as many cytokines and reactive oxygen species (ROS). In addition, in some circumstances, they produce neutrophil extracellular traps (NETs), which is unfolded DNA fibers showing such a web-like structure containing histone and various proteins. However, recent studies have suggested NETs can promote tumor metastasis. In fact, many neutrophils are infiltrating in tumor tissues which are called tumor associated neutrophils (TAN) and high TANs are associated with poor prognosis. However, the detailed effects of TAN on tumor cell behavior are still not fully understood. Methods: Human peripheral polymorph neutrophils (PMN) collected from healthy donor were stimulated with 1μM PMA or 10μg/ml LPS for 15 min, washed extensively, and incubated for another 3 hours. Using trans-well system with culture inserts with 8μm pore membrane, we examined the migration of human gastric cancer cells NUGC-4 or MKN45 to 2% FBS placed in lower chamber with or without PMN. Random migration was also examined with time-lapsed analysis. Lamellipodia were detected with F-actin stained with phalloidin-488 and immunostaining to vinculin. Results: PMN stimulated with either PMA or LPS produced large amounts of NETs stained with SYTOX. NUGC-4 and MKN45 showed little migration to unstimulated PMN, while many cells did migrate when PMA-activated PMN were present in lower chamber. Although NET-depleted supernatants (SN) also induced significant migration, the number of migrated cells was reduced to about 50%. When catalase (800U/ml) catalase was added, the migrations of NUGC-4 was significantly reduced (37%). Random migration was markedly enhanced by NET-depleted SN. Addition of the SN induced many lamellipodia in NUGC-4 within 30 min. The migration of NUGC-4 was also increased by PMN stimulated by LPS, but not by their NET-depleted SN. Summary and Conclusion: PMA-stimulated neutrophils induce robust migration of cancer cells which is partly dependent on H2O2. LPS-stimulated neutrophils appear to produce less amounts of ROS, but can also enhance the NUGC-4 migration through NET dependent manner. Activated neutrophils in tumor microenvironment can stimulate migration of cancer cells through multiple mechanisms, and assist the initial step of metastatic process of primary tumor. Citation Format: Kazuya Takahashi, Hideyuki Ohzawa, Yuki Kaneko, Yurie Futoh, Kohei Tamura, Yuki Kimura, Akira Saito, Mineyuki Tojo, Rihito Kanamaru, Hideyo Miyato, Naohiro Sata, Joji Kitayama. Activated neutrophils induce robust mesenchymal migration of gastric cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6289.

Abstract 1573: Paradoxical roles of peritumoral myofibroblasts in intrahepatic cholangiocarcinoma growth and metastasis

Abstract Background and Rationale: Intrahepatic cholangiocarcinoma (iCCA) is an aggressive type of primary liver cancer characterized by its highly desmoplastic stroma. Compared to the ample knowledge on the protumorigenic functions of iCCA intratumoral myofibroblasts (iMFs), little is known about the activation status of MFs in the tumor-surrounding liver (peritumoral myofibroblasts, pMFs) and their potential role in iCCA development. Results: We examined MF activation in both patient iCCA tumors and an iCCA orthotopic allograft mouse model. We found there was a significant, tumor-induced activation and accumulation of pMFs at the tumor border. Using an in vitro spheroid coculture system, we confirmed that iCCA-liver interaction induced rapid pMF activation at their interface. We found that MFs mixed within tumor spheroids as iMFs had a pro-proliferative effect on iCCA tumor cells similar to the previous reports. However, when the same MFs were seeded around iCCA spheroids as pMFs, they exerted a strong suppressive effect on tumor cells growth. Interestingly, prolonged iCCA-pMF coculture elicited marked tumor cell invasion and dissemination which did not occur in iCCA-iMF coculture. We found vascular cell adhesion protein 1 (Vcam1), a glycoprotein that has been implicated in solid tumor metastasis, was part of the dynamic regulation of tumor cell behaviors by iCCA-pMF interaction. Vcam1 was upregulated in the tumor cells at the early, growth-suppressing phase of iCCA-pMF interaction both in vitro and in vivo, and was then downregulated in tumor cells when they started to disseminate. Systemic blocking of Vcam1 activity in iCCA allograft mouse models using a Vcam1 neutralizing antibody slowed the primary tumor growth but promoted tumor cell dissemination. Conclusion: Our data suggest that pMFs are beyond simple pro- or anti-tumorigenic in iCCA development. iCCA development induces rapid activation and accumulation of pMFs at the tumor border which suppress tumor growth at early stage but eventually elicit tumor cell dissemination at late stage. Citation Format: Cheng Tian, Liyuan Li, Yizhen Li, Wentao Yang, Li Fan, Anthony Brown, Michelle Morrison, Jun J. Yang, Evan S. Glazer, Liqin Zhu. Paradoxical roles of peritumoral myofibroblasts in intrahepatic cholangiocarcinoma growth and metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1573.

Extracellular sialyltransferase st6gal1 in breast tumor cell growth and invasiveness

The sialyltransferase ST6GAL1 that adds α2–6 linked sialic acids to N-glycans of cell surface and secreted glycoproteins is prominently associated with many human cancers. Tumor-native ST6GAL1 promotes tumor cell behaviors such as invasion and resistance to cell stress and chemo- and radio-treatments. Canonically, ST6GAL1 resides in the intracellular secretory apparatus and glycosylates nascent glycoproteins in biosynthetic transit. However, ST6GAL1 is also released into the extracellular milieu and extracellularly remodels cell surface and secreted glycans. The impact of this non-canonical extrinsic mechanism of ST6GAL1 on tumor cell pathobiology is not known. We hypothesize that ST6GAL1 action is the combined effect of natively expressed sialyltransferase acting cell-autonomously within the ER-Golgi complex and sialyltransferase from extracellular origins acting extrinsically to remodel cell-surface glycans. We found that shRNA knockdown of intrinsic ST6GAL1 expression resulted in decreased ST6GAL1 cargo in the exosome-like vesicles as well as decreased breast tumor cell growth and invasive behavior in 3D in vitro cultures. Extracellular ST6GAL1, present in cancer exosomes or the freely soluble recombinant sialyltransferase, compensates for insufficient intrinsic ST6GAL1 by boosting cancer cell proliferation and increasing invasiveness. Moreover, we present evidence supporting the existence novel but yet uncharacterized cofactors in the exosome-like particles that potently amplify extrinsic ST6GAL1 action, highlighting a previously unknown mechanism linking this enzyme and cancer pathobiology. Our data indicate that extracellular ST6GAL1 from remote sources can compensate for cellular ST6GAL1-mediated aggressive tumor cell proliferation and invasive behavior and has great clinical potential for extracellular ST6GAL1 as these molecules are in the extracellular space should be easily accessible targets.

FRA-1: A key factor regulating signal transduction of tumor cells and a potential target molecule for tumor therapy.

Fos-related antigen-1 (FRA-1) is a member of activator protein-1 (AP-1) transcription factor superfamily, and FRA-1 is highly expressed in colon cancer, breast cancer, gastric cancer, lung cancer, bladder cancer, and other tumors. The expression level of FRA-1 is closely related to the processes of tumor cell proliferation, apoptosis, transformation, migration, and invasion, which is a potential therapeutic target and prognostic factor for many tumors. Clarifying the detailed mechanism of action of FRA-1 could provide the theoretical basis for tumor diagnosis, treatment, and prognosis, and is of great significance for the study of tumor etiology and pathogenesis. In this paper, the expression levels and influencing factors of FRA-1 in various tumor tissues and cells are summarized, as well as the effect of FRA-1 expression level on the biological behavior of tumor cells and the signal transduction mechanism. At the same time, the signal transduction mechanism of FRA-1 in inflammation was expounded. In addition, the related metabolites, drugs and non-coding RNA that affect the expression and function of FRA-1 were summarized. Finally, it illustrates that FRA-1 may be taken as a key factor for tumor prognosis and a potential therapeutic target. This review provides a theoretical basis for the systematic understanding of the relationship between FRA-1 and tumors, its function, and possible mechanism.

Identifying biomarkers associated with tumor growth rate: a longitudinal preoperative magnetic resonance imaging follow-up of low-grade gliomas.

BackgroundAlthough the influence of molecular biomarkers on the biological behavior of tumor cells has been investigated, their quantitative influence on the velocity of tumor growth remains unclear. This study aimed to identify the molecular biomarkers associated with tumor growth rates in World Health Organization (WHO) grade II gliomas, or low-grade gliomas (LGGs).MethodsPreoperative magnetic resonance imaging (MRI) data of patients with LGGs were retrospectively reviewed. Patients with at least 2 preoperative MRIs taken more than 90 days apart were enrolled. Patients with isocitrate dehydrogenase (IDH) wild-type tumors or with no recorded IDH status were excluded. A linear mixed-effects model was used to assess the velocity of tumor diameter expansion. The effect of biomarker expression on tumor growth rate was assessed using a multivariate linear mixed-effects regression model.ResultsData from 56 patients were used in our study. The overall velocity of diameter expansion (VDE) for LGGs was 2.1 mm/year. Higher expression level of mutant p53 were significantly associated with a higher tumor growth rate (+1.9 mm/year, P<0.01), while higher expression level of alpha-thalassemia/mental retardation syndrome X-linked protein (ATRX) were significantly associated with a lower tumor growth rate (−1.3 mm/year, P<0.01). Tumors with O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation were found to grow significantly more slowly than those with no methylation (−3.1 mm/year, P<0.01). The telomerase reverse transcriptase (TERT) promoter type and expressions levels of Ki-67 and epidermal growth factor receptor (EGFR) showed no significant independent impact on tumor growth rates.ConclusionsThe status of biomarkers is significantly associated with the tumor growth rate in LGGs.

Cancer stem cell markers CD44v9+/CD133- are associated with low apoptosis in both sporadic and ulcerative colitis-associated colorectal cancers.

To elucidate tumor cell behavior associated with cancer stem cell (CSC) marker expression, the expression of CD133, CD44v9, and ALDH1A1, which are considered markers of CSCs, was examined in sporadic and ulcerative colitis (UC)-associated colorectal tumors. A total of 23 cases of sporadic colorectal cancer and 44 cases of adenoma were collected. Additionally, 22 cancer lesions and 38 dysplasia lesions were selected from 28 colectomy cases of UC with neoplastic lesions. Lesions were examined by immunohistochemistry using primary antibodies against CD133, CD44v9, ALDH1A1, Ki-67, cleaved-Caspase 3, and p53. CD133, CD44v9, and ALDH1A1 showed higher expression in both sporadic and UC-associated tumors than in the normal mucosa. ALDH1A1 expression in sporadic cancer was higher in the right colon than in the left colon (p=0.0089). ALDH1A1 expression in UC-associated cancer was higher in those with longer disease duration than in those with shorter disease duration (p=0.019). The CD44v9+/CD133- region had fewer cleaved-Caspase 3 positive cells in both sporadic and UC-associated cancers. In sporadic cancer, CD133+/ALDH1A1+ regions had fewer apoptotic cells than CD133+/ALDH1A1- regions, while CD133+/ALDH1A1- regions were less proliferative than CD133+/ALDH1A1+ regions in UC-associated cancer. CD44+/CD133- regions were commonly associated with low apoptosis in sporadic and UC-associated cancers; thus, these were considered target areas for CSCs. Additionally, the combination of markers comprising CSCs may differ between sporadic and UC-associated cancers.

Astaxanthin Inhibits Helicobacter pylori-Induced MMPs Expression and Cell Invasion by Suppressing PI3K-AKT-mTOR Pathways in AGS Cells

ObjectivesMatrix metalloproteinases (MMPs) are members of the metzincin group of proteases which can degrade various components of extracellular matrix components (ECM). ECM degradation by MMPs not only enhances tumor invasion but also affects tumor cell behavior and leads to cancer progression. Resent reports demonstrated that PI3K-AKT-mTOR signaling pathways are involved in expression of MMPs. Especially when it comes to gastric cancer, H. pylori infection promotes the invasion and metastasis of tumor cells by reactive oxygen species (ROS). Astaxanthin, a xanthophyll carotenoid, has been well known for its strong antioxidant and anticancer properties. Thus, the present study was aimed to investigate the inhibitory effects and mechanisms of astaxanthin on H. pylori-induced MMPs expression and cell invasion in human gastric epithelial cells.MethodsHuman gastric epithelial cell lines, AGS were used. AGS cells were pre-treated with astaxanthin for 3 hours prior to H. pylori (cag A positive NCTC 11,637 strains) infection at bacterium/cell ratio of 50:1 and cultured for 24 hours in the presence of H. pylori. mRNA expression and protein levels of MMP-7 and 10 was measured by real time PCR and Western blot analysis, respectively. Intracellular ROS levels were determined using DCF-DA. Invasive cell phenotype was measured using invasion assay.ResultsAstaxanthin inhibited expression of MMP-7&10. Intracellular ROS production and cell invasion induced by H. pylori was inhibited by astaxanthin. In addition, H. pylori-induced activation of PI3K-AKT-mTOR was inhibited by astaxanthin.ConclusionsAstaxanthin exerts an inhibitory effect on H. pylori-induced MMPs expression and cell invasion by suppression of ROS production and PI3K-AKT-mTOR signaling pathway in gastric epithelial cells. Thus astaxanthin may hold promise for clinical cancer therapy.Funding SourcesNo funding sources.

Epigenetics Regulates Antitumor Immunity in Melanoma

Melanoma is the most malignant skin cancer, which originates from epidermal melanocytes, with increasing worldwide incidence. The escape of immune surveillance is a hallmark of the tumor, which is manifested by the imbalance between the enhanced immune evasion of tumor cells and the impaired antitumor capacity of infiltrating immune cells. According to this notion, the invigoration of the exhausted immune cells by immune checkpoint blockades has gained encouraging outcomes in eliminating tumor cells and significantly prolonged the survival of patients, particularly in melanoma. Epigenetics is a pivotal non-genomic modulatory paradigm referring to heritable changes in gene expression without altering genome sequence, including DNA methylation, histone modification, non-coding RNAs, and m6A RNA methylation. Accumulating evidence has demonstrated how the dysregulation of epigenetics regulates multiple biological behaviors of tumor cells and contributes to carcinogenesis and tumor progression in melanoma. Nevertheless, the linkage between epigenetics and antitumor immunity, as well as its implication in melanoma immunotherapy, remains elusive. In this review, we first introduce the epidemiology, clinical characteristics, and therapeutic innovations of melanoma. Then, the tumor microenvironment and the functions of different types of infiltrating immune cells are discussed, with an emphasis on their involvement in antitumor immunity in melanoma. Subsequently, we systemically summarize the linkage between epigenetics and antitumor immunity in melanoma, from the perspective of distinct paradigms of epigenetics. Ultimately, the progression of the clinical trials regarding epigenetics-based melanoma immunotherapy is introduced.

P53 wild-type colorectal cancer cells that express a fetal gene signature are associated with metastasis and poor prognosis

Current therapy against colorectal cancer (CRC) is based on DNA-damaging agents that remain ineffective in a proportion of patients. Whether and how non-curative DNA damage-based treatment affects tumor cell behavior and patient outcome is primarily unstudied. Using CRC patient-derived organoids (PDO)s, we show that sublethal doses of chemotherapy (CT) does not select previously resistant tumor populations but induces a quiescent state specifically to TP53 wildtype (WT) cancer cells, which is linked to the acquisition of a YAP1-dependent fetal phenotype. Cells displaying this phenotype exhibit high tumor-initiating and metastatic activity. Nuclear YAP1 and fetal traits are present in a proportion of tumors at diagnosis and predict poor prognosis in patients carrying TP53 WT CRC tumors. We provide data indicating the higher efficacy of CT together with YAP1 inhibitors for eradication of therapy resistant TP53 WT cancer cells. Together these results identify fetal conversion as a useful biomarker for patient prognosis and therapy prescription.

47P Immune tumor microenvironment and markers of apoptosis in breast cancer in carriers of hereditary mutations in the BRCA1 gene

Tumor immune microenvironment is currently recognized as an important participant in carcinogenesis, influencing the behavior of tumor cells and treatment efficacy. It is suggested that defects in BRCA1/2 genes contribute to a high mutation load and high immunogenicity, which modulates immune microenvironment. At the same time, it was shown that BRCA1/2-associated breast cancer tumors do not belong to the category of immunoactive ones. In addition, there is evidence of the additional evaluation of TP53 mutation in these tumors and disruption of the cell death process, which can also be a factor of resistance to therapy. 40 patients with breast cancer with BRCA1 mutations 185delAG, 4153delA, 5382insC, 3819DELGTAA, 3875delGTCT, 300T>G, 2080delA and BRCA2 (6174delT)) determined by real-time polymerase chain reaction (PCR) were included. Immunohistochemical study was performed using monoclonal antibodies to Ki67, p53, CD8, CD4, CD68, CD163, BCL2. In the presented study patients with BRCA1-associated breast cancer, had high low tumor CD4/CD8 ratio in 50% of cases, which characterizes an immunosuppressive microenvironment. Mutation BRCA1 5382insC is associated with high level of CD4+ T-lymphocytes (p˂0.05), G3 is associated with a low CD4/CD8 ratio (p=0.056) and a low levels of CD68+M1, CD163+M2-macrophages (p=0,022, p=0.002); T1 correlates with high levels of CD8+ TILs (p=0.038) and high levels of CD163 (p=0.033). High Ki-67 is associated with a lack of BCL2 expression (p=0.04). Negative expression of BCL2 occurred in 52.5% of cases. A high level of p53 expression is described as the main type of expression in these tumors, suggesting a combination of TB53 and BRCA1 mutations and a violation of the mechanism of cell death in these patients. The immunosuppressive type of microenvironment prevails in the tumors of breast cancer patients with hereditary mutations in the BRCA1 gene, where a violation of the mechanism of cell death in BRCA1-deficient breast cancer was revealed. The main directions of future therapy of these tumors may be modification of the immune microenvironment and activation of the mechanisms of cell death.

Dynamical analysis of tumor model with obesity and immunosuppression

In this paper, we have studied a three-dimensional model to describe the behavior of tumor cells in the absence of the immune response, which is composed of tumor, normal and fat cells (TNF) under time delay effect. The center manifold theory has been used to study the bifurcation behavior. It is proven that TNF model undergoes codimension-1 bifurcation, while Hopf bifurcation does not occur in the non-delay model. For delayed TNF, we take into the late response of fat cells to tumor cells. Consequently, the delay factor is a considerable parameter in TNF model. Hence, we presented a formula of the time delay value for the occurrence of periodic solutions. Additionally, the stability of Hopf bifurcation was analysed. Numerical simulations are provided to illustrate and extend the theoretical results, we provide our study with numerical simulations inclusive families of periodic solutions.

RIG-I acts as a tumor suppressor in melanoma via regulating the activation of the MKK/p38MAPK signaling pathway

Studies have indicated that RIG-I may act as a tumor suppressor and participate in the tumorigenesis of some malignant diseases. However, RIG-I induces distinct cellular responses via different downstream signaling pathways depending on the cell type. To investigate the biological function and underlying molecular mechanism of RIG-I in the tumorigenesis of melanoma, we constructed RIG-I knockout, RIG-I-overexpressing B16-F10 and RIG-I knockdown A375 melanoma cell lines, and analyzed the RIG-I-mediated change in the biological behavior of tumor cells in spontaneous and poly (I:C)-induced RIG-I activation. Cell proliferation, cell cycling, apoptosis and migration were detected by CCK-8 assay, BrdU incorporation assay, Annexin V–PI staining assay and Transwell assay, respectively. In vivo tumorigenicity was evaluated by tumor xenograft growth in nude mice and subsequently by Ki67 staining and TUNEL assays. Furthermore, Western blotting was utilized to explore the underlying mechanism of RIG-I in melanoma cells. Our data showed that RIG-I promotes apoptosis and inhibits proliferation by G1 phase cell cycle arrest in the melanoma cell lines. Mechanistically, RIG-I induced the phosphorylation of p38 MAPK and MAPK kinases MKK3 and MKK4. In conclusion, the current study demonstrated that RIG-I suppressed the development of melanoma by regulating the activity of the MKK/p38 MAPK signaling pathway, which is relevant to research on novel therapeutic targets for this malignant disease.

Prolonged exposure to simulated microgravity promotes stemness impairing morphological, metabolic and migratory profile of pancreatic cancer cells: a comprehensive proteomic, lipidomic and transcriptomic analysis

BackgroundThe impact of the absence of gravity on cancer cells is of great interest, especially today that space is more accessible than ever. Despite advances, few and contradictory data are available mainly due to different setup, experimental design and time point analyzed.MethodsExploiting a Random Positioning Machine, we dissected the effects of long-term exposure to simulated microgravity (SMG) on pancreatic cancer cells performing proteomic, lipidomic and transcriptomic analysis at 1, 7 and 9 days.ResultsOur results indicated that SMG affects cellular morphology through a time-dependent activation of Actin-based motility via Rho and Cdc42 pathways leading to actin rearrangement, formation of 3D spheroids and enhancement of epithelial-to-mesenchymal transition. Bioinformatic analysis reveals that SMG may activates ERK5/NF-κB/IL-8 axis that triggers the expansion of cancer stem cells with an increased migratory capability. These cells, to remediate energy stress and apoptosis activation, undergo a metabolic reprogramming orchestrated by HIF-1α and PI3K/Akt pathways that upregulate glycolysis and impair β-oxidation, suggesting a de novo synthesis of triglycerides for the membrane lipid bilayer formation.ConclusionsSMG revolutionizes tumor cell behavior and metabolism leading to the acquisition of an aggressive and metastatic stem cell-like phenotype. These results dissect the time-dependent cellular alterations induced by SMG and pave the base for altered gravity conditions as new anti-cancer technology.