Behavior Of Tumor Cells Research Articles

Integrins Can Act as Suppressors of Ras-Mediated Oncogenesis in the Drosophila Wing Disc Epithelium.

Cancer is the second leading cause of death worldwide. Key to cancer initiation and progression is the crosstalk between cancer cells and their microenvironment. The extracellular matrix (ECM) is a major component of the tumour microenvironment and integrins, main cell-ECM adhesion receptors, are involved in every step of cancer progression. However, accumulating evidence has shown that integrins can act as tumour promoters but also as tumour suppressor factors, revealing that the biological roles of integrins in cancer are complex. This incites a better understating of integrin function in cancer progression. To achieve this goal, simple model organisms, such as Drosophila, offer great potential to unravel underlying conceptual principles. Here, we find that in the Drosophila wing disc epithelium the βPS integrins act as suppressors of tumours induced by a gain of function of the oncogenic form of Ras, RasV12. We show that βPS integrin depletion enhances the growth, delamination and invasive behaviour of RasV12 tumour cells, as well as their ability to affect the tumour microenvironment. These results strongly suggest that integrin function as tumour suppressors might be evolutionarily conserved. Drosophila can be used to understand the complex tumour modulating activities conferred by integrins, thus facilitating drug development.

Cellular crosstalk of macrophages and therapeutic implications in non-small cell lung cancer revealed by integrative inference of single-cell transcriptomics.

Introduction: Non-small cell lung cancer (NSCLC) exhibits heterogeneity with diverse immune cell infiltration patterns that can influence tumor cell behavior and immunotherapy. A comprehensive characterization of the tumor microenvironment can guide precision medicine. Methods: Here, we generated a single-cell atlas of 398170 cells from 52 NSCLC patients, and investigated the imprinted genes and cellular crosstalk for macrophages. Subsequently, we evaluated the effect of tumor cells on macrophages and verified the expression of marker genes using co-culture experiments, flow cytometry and RT-qPCR assays. Results: Remarkable macrophage adaptability to NSCLC environment was observed, which contributed to generating tumor-associated macrophages (TAMs). We identified 5 distinct functional TAM subtypes, of which the majority were SELENOP-positive macrophages, with high levels of SLC40A1 and CCL13. The TAMs were also involved in mediating CD8+ T cell activity and form intercellular interaction with cancer cells, as indicated by receptor-ligand binding. Indirect coculture of tumor cells SPC-A1 and THP-1 monocytes, produced M2-like TAMs that highly expressed several markers of SELENOP-positive macrophages. The abundance of this type TAMs seemed to be associated with poorer overall survival rates [hazard ratio (HR) = 1.34, 95% confidence interval (CI) = 0.98-1.83, p = 0.068] based on deconvolution of TCGA-LUAD dataset. Discussion: In summary, we provided a high-resolution molecular resource of TAMs, and displayed the acquired properties in the tumor microenvironment. Dynamic crosstalk between TAMs and tumor cells via multiple ligand-receptor pairs were revealed, emphasizing its role in sustaining the pro-tumoral microenvironment and its implications for cancer therapy.

Formation of an invasion-permissive matrix requires TGFβ/SNAIL1-regulated alternative splicing of fibronectin

BackgroundAs in most solid cancers, the emergence of cells with oncogenic mutations in the mammary epithelium alters the tissue homeostasis. Some soluble factors, such as TGFβ, potently modify the behavior of healthy stromal cells. A subpopulation of cancer-associated fibroblasts expressing a TGFβ target, the SNAIL1 transcription factor, display myofibroblastic abilities that rearrange the stromal architecture. Breast tumors with the presence of SNAIL1 in the stromal compartment, and with aligned extracellular fiber, are associated with poor survival prognoses.MethodsWe used deep RNA sequencing and biochemical techniques to study alternative splicing and human tumor databases to test for associations (correlation t-test) between SNAIL1 and fibronectin isoforms. Three-dimensional extracellular matrices generated from fibroblasts were used to study the mechanical properties and actions of the extracellular matrices on tumor cell and fibroblast behaviors. A metastatic mouse model of breast cancer was used to test the action of fibronectin isoforms on lung metastasis.ResultsIn silico studies showed that SNAIL1 correlates with the expression of the extra domain A (EDA)-containing (EDA+) fibronectin in advanced human breast cancer and other types of epithelial cancers. In TGFβ-activated fibroblasts, alternative splicing of fibronectin as well as of 500 other genes was modified by eliminating SNAIL1. Biochemical analyses demonstrated that SNAIL1 favors the inclusion of the EDA exon by modulating the activity of the SRSF1 splicing factor. Similar to Snai1 knockout fibroblasts, EDA- fibronectin fibroblasts produce an extracellular matrix that does not sustain TGFβ-induced fiber organization, rigidity, fibroblast activation, or tumor cell invasion. The presence of EDA+ fibronectin changes the action of metalloproteinases on fibronectin fibers. Critically, in an mouse orthotopic breast cancer model, the absence of the fibronectin EDA domain completely prevents lung metastasis.ConclusionsOur results support the requirement of EDA+ fibronectin in the generation of a metastasis permissive stromal architecture in breast cancers and its molecular control by SNAIL1. From a pharmacological point of view, specifically blocking EDA+ fibronectin deposition could be included in studies to reduce the formation of a pro-metastatic environment.

CNSC-32. SIMULTANEOUS INVESTIGATION OF TUMOR CELL BEHAVIOR AND CONNECTIVITY WITH CORRELATIVE IN VIVO TWO-PHOTON AND EX VIVO EXPANSION MICROSCOPY

Abstract Glioblastomas are the most aggressive primary brain tumors, characterized by whole-brain colonization, high therapeutic resistance, and inevitable recurrence. It has previously been shown that glioblastoma cells can form functionally gap-junction connected tumor cell networks with other tumor cells and/or astrocytes, which play a crucial role in tumor progression and treatment response. Furthermore, there is increasing evidence that synaptic neuron-glioma networks promote tumor growth. However, methodologies to investigate the direct link between synaptic, astrocytic and tumor cell connectivity together with tumor cell behavior including invasion, proliferation and therapeutic resistance are yet lacking. We aimed to characterize neuron-tumor and tumor-tumor/astrocyte cell interactions on a single cell level by using correlative in vivo two-photon and ex vivo expansion microscopy with near synaptic-resolution. We studied glioblastoma cells with intravital two-photon microscopy using patient-derived glioblastoma mouse models and the fluorescent functional imaging dye Sulforhodamine 101 allowing to investigate intratumoral and astrocytic connectivity over an extended period up to weeks. Subsequently, these functional tumor cell subpopulations could be directly correlated ex vivo to identify neuron-glioma synaptic connectivity. We utilized machine learning based segmentation and a semi-automated analysis pipeline to explore the connection of different glioblastoma morphological and behavioral subtypes to direct and indirect neuronal input in multiple xenograft models. With this new correlative method, we were able to simultaneously evaluate tumor cell behavior, synaptic and tumor-tumor/astrocyte connections on a single cell level. In addition, we demonstrated that this pipeline can be used for patient samples, revealing its clinical-translational potential for cancer neuroscience. In summary, we have established a new correlative technology that interlinks two key aspects of brain cancer neuroscience: cancer cell behavior and brain tumor network connectivity. This methodology promises a more thorough understanding of glioblastoma biology, facilitating the discovery of cancer biology, including the role of brain tumor networks in therapeutic resistance.

STEM-22. SINGLE-CELL LINEAGE TRACING IN PRIMARY GLIOBLASTOMA REVEALS DISTINCT PROGENITOR SUBTYPES DRIVING INTRATUMORAL HETEROGENEITY

Abstract Glioblastoma (GBM) is the most common type of adult primary brain tumor with nearly a 100% rate of recurrence. One of the key clinical challenges is the vast degree of inter- and intra-tumoral variation in cell types and cell states, which change throughout the course of disease. Single-cell RNA-sequencing (scRNA-seq) studies in GBM samples have illuminated the complex landscape of cell type composition in primary and recurrent GBM, however these studies do not address how this diverse array of cell types developed or which cell populations are principally responsible for generating the heterogeneity and treatment resistance in the tumor. In this study, we implement a scRNA-seq compatible lineage tracing strategy, CellTagging, to track the behavior of individual tumor cells over time. Human GBM samples are dissociated immediately upon resection and infected with the CellTag DNA barcode library. The labeled cells are transplanted onto human cortical organoids, which facilitate the crucial normal-tumor cell interactions that enable GBM growth and invasion. After a period of proliferation, tumor cells are dissociated from the organoid and a fraction are harvested for scRNA-seq for transcriptomic and DNA barcode analysis. The remaining tumor cells are re-transplanted onto new organoids and harvested for scRNA-seq at later timepoints. Clonal relationships are determined by identifying cells with the same DNA barcode profile, and cell type characterizations are assigned via transcriptomic analysis. Transcriptomic profiling demonstrates the existence of multiple subtypes of tumor progenitors across timepoints. Strikingly, clonal analysis indicates that each progenitor subtype gives rise to numerous mature tumor cell types, suggesting multiple distinct lineages that contribute to tumor heterogeneity. Through differential expression analysis, we can predict which progenitors are most likely to drive which cell states. By introducing a treatment paradigm into our lineage tracing protocol, we identify tumor progenitor populations that contribute to treatment resistance.

Microenvironmental stress drives tumor cell maladaptation and malignancy through regulation of mitochondrial and nuclear cytochrome c oxidase subunits.

After decades of focus on molecular genetics in cancer research, the role of metabolic and environmental factors is being reassessed. Here, we investigated the role of microenvironment in the promotion of malignant behavior in tumor cells with a different reliance on oxidative phosphorylation (OXPHOS) versus lactic acid fermentation/Warburg effect. To this end, we evaluated the effects of microenvironmental challenges (hypoxia, acidity, and high glucose) on the expression of mitochondrial-encoded cytochrome c oxidase 1 (COX I) and two nuclear-encoded isoforms 4 (COX IV-1 and COX IV-2). We have shown that tumor cells with an "OXPHOS phenotype" respond to hypoxia by upregulating COX IV-1, whereas cells that rely on lactic acid fermentation maximized COX IV-2 expression. Acidity upregulates COX IV-2 regardless of the metabolic state of the cell, whereas high glucose stimulates the expression of COX I and COX IV-1, with a stronger effect in fermenting cells. Our results uncover that "energy phenotype" of tumor cells drives their adaptive response to microenvironment stress.NEW & NOTEWORTHY How microenvironmental stress (hypoxia, acidity, and high glucose) supports tumor growth has not yet been fully elucidated. Here, we demonstrated that these stressors promote malignancy by controlling the expression of cytochrome c oxidase I (COX I), and COX IV-1 and COX IV-2 based on the "energy phenotype" of cancer cells (OXPHOS vs. fermentation). Our results uncover a novel process by which the "energy phenotype" of cancer cells drives the adaptive response to microenvironment stress.

Glycocalyx transduces membrane leak in brain tumor cells exposed to sharp magnetic pulsing

Mechanisms by which electric (E) or magnetic (B) fields might be harnessed to affect tumor cell behavior remain poorly defined, presenting a barrier to translation. We hypothesized in early studies that the glycocalyx of lung cancer cells might play a role in mediating plasma membrane leak by low-frequency pulsed magnetic fields (Lf-PMF) generated on a low-energy solenoid platform. In testing glioblastoma and neuroblastoma cells known to overexpress glycoproteins rich in modifications by the anionic glycan sialic acid (Sia), exposure of brain tumor cells on the same platform to a pulse train that included a 5 min 50Hz Lf-PMF (dB/dt ∼ 2 T/s at 10 ms pulse widths) induced a very modest but significant protease leak above that of control nonexposed cells (with modest but significant reductions in long-term tumor cell viability after the 5 min exposure). Using a markedly higher dB/dt system (80 T/s pulses, 70 μs pulse-width at 5.9 cm from a MagVenture coil source) induced markedly greater leak by the same cells, and eliminating Sia by treating cells with AUS sialidase immediately preexposure abrogated the effect entirely in SH-SY5Y neuroblastoma cells, and partially in T98G glioblastoma cells. The system demonstrated significant leak (including inward leak of propidium iodide), with reduced leak at lower dB/dt in a variety of tumor cells. The ability to abrogate Lf-PMF protease leak by pretreatment with sialidase in SH-SY5Y brain tumor cells or with heparin lyase in A549 lung tumor cells indicated the importance of heavy Sia or heparan sulfate glycosaminoglycan glycocalyx modifications as dominant glycan species mediating Lf-PMF membrane leak in respective tumor cells. This “first-physical” Lf-PMF tumor glycocalyx event, with downstream cell stress, may represent a critical and “tunable” transduction mechanism that depends on characteristic anionic glycans overexpressed by distinct malignant tumors.

Treatment-prognostication-adjustment a new therapeutic idea by analyzing T cell immune checkpoint in tumor microenvironment by algorithm: A bibliometric analysis

ABSTRACT To evaluate the temporal and spatial distribution of the knowledge network about tumor microenvironment and prognoses and explore new research hot spots and trends. Articles and reviews on tumor microenvironment and prognoses in the Web of Science journal from January 1999 to April 2022 were included. We used the CiteSpace and VOSviewer software to analyze the knowledge network composed of journals, institutions, countries, authors, and keywords. Frontiers in Immunology, Cancers, and Frontiers in Oncology have published more than 10% of articles in this field. China and the United States have contributed the most articles. Fudan University and Sun Yat-Sen University are the most active institutions. The authors in this field work closely; Zhang Wei and Douglas have made outstanding contributions. The three main research areas of tumor microenvironment and prognoses are microenvironment, prognosis, and immunotherapy. Until 2020, the main keywords were endothelial growth factor and adhesion. In the past three years, survival analysis, immune cell infiltration, and prediction model have been used. It can be seen that the focus in this field has shifted from tumor cell behavior and directly related molecules to prognosis prediction and non-tumor cells in the microenvironment. The future research trend may be to study the changes in the tumor microenvironment to predict the prognosis and guide the treatment. VOSviewer, CiteSpace, and Microsoft Excel 2019 were used to conduct a comprehensive visual analysis of the research on tumor environment and prognoses and provide valuable reference materials for researchers.

Critical Roles of SRC-3 in the Development and Progression of Breast Cancer, Rendering It a Prospective Clinical Target

Breast cancer (BCa) is the most frequently diagnosed malignant tumor in women and is also one of the leading causes of cancer-related death. Most breast tumors are hormone-dependent and estrogen signaling plays a critical role in promoting the survival and malignant behaviors of these cells. Estrogen signaling involves ligand-activated cytoplasmic estrogen receptors that translocate to the nucleus with various co-regulators, such as steroid receptor co-activator (SRC) family members, and bind to the promoters of target genes and regulate their expression. SRC-3 is a member of this family that interacts with, and enhances, the transcriptional activity of the ligand activated estrogen receptor. Although SRC-3 has important roles in normal homeostasis and developmental processes, it has been shown to be amplified and overexpressed in breast cancer and to promote malignancy. The malignancy-promoting potential of SRC-3 is diverse and involves both promoting malignant behavior of tumor cells and creating a tumor microenvironment that has an immunosuppressive phenotype. SRC-3 also inhibits the recruitment of tumor-infiltrating lymphocytes with effector function and promotes stemness. Furthermore, SRC-3 is also involved in the development of resistance to hormone therapy and immunotherapy during breast cancer treatment. The versatility of SRC-3 in promoting breast cancer malignancy in this way makes it a good target, and methodical targeting of SRC-3 probably will be important for the success of breast cancer treatment.

In Vitro Tumor Mimetic Spheroid Model: Void Space within a Self-Detachable Cross-Linked Hydrogel.

The three-dimensional (3D) spheroid cell culture model is crucial in screening anticancer drugs in vitro and understanding tumor cell behavior. However, the current in vitro models require highly skilled techniques. Here, we present an in vitro, tumor-mimetic, self-detachable, cancer cell spheroid model that provides the confined space of a tumor microenvironment, convenient spheroid retrieval, immunostaining, treatment, and imaging. We formed a void space within alginate macrobeads by ionic disintegration at a specific region inside. The macrobeads were further destabilized with bovine serum albumin to retrieve the spheroid cultured within the void space. Quantitative analysis of the immunofluorescence images of the cultured spheroids showed enhanced expressions of the hypoxia-inducible factor-1α (HIF-1α) and carbonic anhydrase-9 (CA-9), like monolayer cultures of cancer cells under hypoxic conditions (0.2% oxygen). Furthermore, adding CoCl2 to the cell culture media induces even higher amounts of HIF-1α and CA-9 in the cultured spheroids. In conclusion, the present work highlighted the in vitro spheroid model, which is closer to the tumor microenvironment and has user-friendly cell seeding, spheroid retrieval, and immunostaining steps.

Expression of an oxysterol-metabolizing enzyme in colorectal cancer and its relation to tumor cell behavior and prognosis

Oxysterols and oxysterol-metabolizing enzymes have been implicated in the pathogenesis of various cancers. However, the distinct function of the oxysterol-metabolizing enzyme cytochrome P450 family 39 Subfamily A Member 1 (CYP39A1) in colorectal cancer (CRC) remains unclear. The aims of the current study were to evaluate whether CYP39A1 affects the oncogenic behaviors of CRC cells and to investigate the prognostic value of its expression in CRC. A CYP39A1 small-interfering RNA was used to block CYP39A1 gene expression in DLD1 and SW480 cells. The expression of CYP39A1 in CRC tissues was investigated by immunohistochemistry. Tumor angiogenesis and lymphangiogenesis were assessed by CD34 and D2–40 immunohistochemical staining, respectively. CYP39A1 knockdown inhibited tumor cell migration and invasion in DLD1 and SW480 cells. Angiogenesis was also inhibited through the decreased expression of vascular endothelial growth factor (VEGF)-A and hypoxia-inducible factor (HIF)−1α, and angiostatin and endostatin expression increased. In addition, CYP39A1 knockdown inhibited the lymphangiogenesis by decreasing the expression of VEGF-C. CYP39A1 expression was increased in CRC tissues compared with normal colorectal mucosa. CYP39A1 expression was associated with tumor stage, depth of invasion, lymph node metastasis, distant metastasis, and poor survival. The microvessel and lymphatic vessel density values of CYP39A1-positive tumors were significantly higher than those of CYP39A1-negative tumors. These results indicate that CYP39A1 is associated with tumor progression by influencing tumor cell angiogenesis and lymphangiogenesis in CRC.

MiRNA/epithelial-mesenchymal axis (EMT) axis as a key player in cancer progression and metastasis: A focus on gastric and bladder cancers

The metastasis a major hallmark of tumors that its significant is not only related to the basic research, but clinical investigations have revealed that majority of cancer deaths are due to the metastasis. The metastasis of tumor cells is significantly increased due to EMT mechanism and therefore, inhibition of EMT can reduce biological behaviors of tumor cells and improve the survival rate of patients. One of the gaps related to cancer metastasis is lack of specific focus on the EMT regulation in certain types of tumor cells. The gastric and bladder cancers are considered as two main reasons of death among patients in clinical level. Herein, the role of EMT in regulation of their progression is evaluated with a focus on the function of miRNAs. The inhibition/induction of EMT in these cancers and their ability in modulation of EMT-related factors including ZEB1/2 proteins, TGF-β, Snail and cadherin proteins are discussed. Moreover, lncRNAs and circRNAs in crosstalk of miRNA/EMT regulation in these tumors are discussed and final impact on cancer metastasis and response of tumor cells to the chemotherapy is evaluated. Moreover, the impact of miRNAs transferred by exosomes in regulation of EMT in these cancers are discussed.

The Dual Role of Mesenchymal Stem Cells in Cancer Pathophysiology: Pro-Tumorigenic Effects versus Therapeutic Potential.

Mesenchymal stem/stromal cells (MSCs) are multipotent cells involved in numerous physiological events, including organogenesis, the maintenance of tissue homeostasis, regeneration, or tissue repair. MSCs are increasingly recognized as playing a major, dual, and complex role in cancer pathophysiology through their ability to limit or promote tumor progression. Indeed, these cells are known to interact with the tumor microenvironment, modulate the behavior of tumor cells, influence their functions, and promote distant metastasis formation through the secretion of mediators, the regulation of cell-cell interactions, and the modulation of the immune response. This dynamic network can lead to the establishment of immunoprivileged tissue niches or the formation of new tumors through the proliferation/differentiation of MSCs into cancer-associated fibroblasts as well as cancer stem cells. However, MSCs exhibit also therapeutic effects including anti-tumor, anti-proliferative, anti-inflammatory, or anti-oxidative effects. The therapeutic interest in MSCs is currently growing, mainly due to their ability to selectively migrate and penetrate tumor sites, which would make them relevant as vectors for advanced therapies. Therefore, this review aims to provide an overview of the double-edged sword implications of MSCs in tumor processes. The therapeutic potential of MSCs will be reviewed in melanoma and lung cancers.

Circ-PRMT5 stimulates the proliferative ability in Wilms' tumor through the miR-7-5p/KLF4 axis.

CircRNAs are extensively discovered in mammals and they are closely linked to tumor cell behaviors. This study aims to detect the expression pattern of circ-PRMT5 in Wilms' tumor and its ability in influencing tumor development. Circ-PRMT5 levels in Wilms' tumor samples were detected. The regulatory effect of circ-PRMT5 on proliferative ability in Wilms' tumor cells was assessed by cell counting kit-8 (CCK-8), colony formation and 5-Ethynyl-2'- deoxyuridine (EdU) assay. The interaction in the circ-PRMT5/miR-7-5p/KLF4 axis was determined by luciferase assay. Rescue experiments were conducted to reveal the role of the circ-PRMT5/miR-7-5p/KLF4 axis in Wilms' tumor development. Circ-PRMT5 was highly expressed in Wilms' tumor samples. High levels of circ-PRMT5 predicted advanced tumor staging in patients with Wilms' tumor. Knockdown of circ-PRMT5 markedly suppressed proliferative ability in Wilms' tumor cells. Luciferase assay confirmed the interaction in the circ-PRMT5/miR-7-5p/KLF4 axis. Rescue experiments finally identified that circ-PRMT5 stimulated the malignant development of Wilms' tumor by activating the miR-7-5p/KLF4 axis. Circ-PRMT5 is upregulated in Wilms' tumor samples, which is closely linked to its tumor staging. It stimulates proliferative ability in Wilms' tumor cells by activating the miR-7-5p/KLF4 axis.

GLIS3, a novel prognostic indicator of gastric adenocarcinoma, contributes to the malignant biological behaviors of tumor cells via modulating TGF-β1/TGFβR1/Smad1/5 signaling pathway

GLIS3 is highly expressed in multiple cancers, but it has not been studied in gastric adenocarcinoma (GAC). Based on bioinformatics analysis, the prognostic significance of GLIS3 in GAC was analyzed. GAC cells were transfected with small interfering (si)-GLIS3 and GLIS3 overexpression plasmid as well as treated with SB505124 [an inhibitor for transforming growth factor beta receptor 1 (TGFβR1)] and dorsomorphin [an inhibitor for bone morphogenetic protein receptor 1 (BMPR1)]. The GLIS3 expression was detected using qRT-PCR. The impacts of GLIS3 on the proliferation, invasion and migration of GAC cells were measured using cell function assays. The activation of phosphor (p)-Smad1/5 was tested by immunofluorescence. Western blot was utilized to measure the level of transforming growth factor (TGF)-β1/Smad1/5 signaling pathway-related proteins (TGF-β1, p-Smad1, Smad1, p-Smad5, Smad5). GLIS3 was expressed at high levels in GAC tissues and cell lines and its high expression could indicate the poor prognosis of GAC patients. GLIS3 inhibition declined the proliferative, invasive and migratory capabilities as well as TGF-β1 expression and phosphorylation of Smad1/5 in GAC cells. Overexpressed GLIS3 promoted proliferation, migration, invasion, TGF-β1 expression and Smad1/5 phosphorylation in GAC cells, with SB505124 reversing the effects of overexpressed GLIS3 on proliferation, migration, invasion and Smad1/5 phosphorylation whereas dorsomorphin exhibiting no influence on GLIS3-induced effects. GLIS3 facilitated the malignant phenotype of GAC cells via regulating TGF-β1/TGFβR1/Smad1/5 pathway, which may be a novel prognostic indicator of GAC and provided a target for GAC treatment.

Immune responses of six-transmembrane epithelial antigen of the prostate 4 functions as a novel biomarker in gastric cancer.

Immune cells play an important role in regulating the behavior of tumor cells. According to emerging evidence, six-transmembrane epithelial antigen of the prostate 4 (STEAP4) performs a crucial part in tumor microenvironmental immune response and tumorigenesis, and serves as the potential target for cellular and antibody immunotherapy. However, the immunotherapeutic role of STEAP4 in gastric cancer (GC) remains unclear. To investigate the expression of STEAP4 in GC and its relationship with immune infiltrating cells, and explore the potential value of STEAP4 as an immune prognostic indicator in GC. The expression level of STEAP4 was characterized by immunohistochemistry in tumors and adjacent non-cancerous samples in 96 GC patients. Tumor Immune Estimation Resource was used to study the correlation between STEAP4 and tumor immune infiltration level and immune infiltration gene signature. R package was used to analyze the relationship between STEAP4 expression and immune and stromal scores in GC (GSE62254) by the ESTIMATE algorithm, and Kaplan-Meier Plotter and Gene Expression Profiling Interactive Analysis were applied to analyze the effect of STEAP4 on clinical prognosis. Immunohistochemistry analysis showed that STEAP4 expression was higher in GC tissues than in adjacent tissues, and STEAP4 expression was positively correlated with the clinical stage of GC. In GC, the expression of STEAP4 was positively correlated with the infiltration levels of B cells, CD4+ T cells, macrophages, neutrophils, and dendritic cells. The expression level of STEAP4 was strongly correlated with most of the immune markers. In addition, STEAP4 expression was inversely correlated with tumor purity, but correlated with stromal score (r = 0.43, P < 0.001), immune score (r = 0.29, P < 0.001) and estimate score (r = 0.39, P < 0.001). Moreover, stromal, immune, and estimate scores were higher in the STEAP4 high expression group, whereas tumor purity was higher in the STEAP4 Low expression group. The relationship between STEAP4 expression and prognosis of patients with GC was further investigated, and the results showed that high STEAP4 expression was associated with poor overall survival and disease-free survival. In addition, Kaplan-Meier Plotter showed that high expression of STEAP4 was significantly correlated with poor survival of patients with GC. The current findings suggest an oncogenic role for STEAP4 in GC, with significantly high levels being associated with poor prognosis. Investigation of the GC tumor microenvironment suggests the potential function of STEAP4 is connected with the infiltration of diverse immune cells, which may contribute to the regulation of the tumor microenvironment. In conclusion, STEAP4 may serve as a potential therapeutic target for GC to improve the immune infiltration, as well as serve as a prognostic biomarker for judging the prognosis and immune infiltration status of GC.

The stress sensor GCN2 differentially controls ribosome biogenesis in colon cancer according to the nutritional context.

Nutrient availability is a key determinant of tumor cell behavior. While nutrient-rich conditions favor proliferation and tumor growth, scarcity, and particularly glutamine starvation, promotes cell dedifferentiation and chemoresistance. Here, linking ribosome biogenesis plasticity with tumor cell fate, we uncover that the amino acid sensor general control non-derepressible 2 (GCN2; also known as eIF-2-alpha kinase 4) represses the expression of the precursor of ribosomal RNA (rRNA), 47S, under metabolic stress. We show that blockade of GCN2 triggers cell death by an irremediable nucleolar stress and subsequent TP53-mediated apoptosis in patient-derived models of colon adenocarcinoma (COAD). In nutrient-rich conditions, a cell-autonomous GCN2 activity supports cell proliferation by stimulating 47S rRNA transcription, independently of the canonical integrated stress response (ISR) axis. Impairment of GCN2 activity prevents nuclear translocation of methionyl-tRNA synthetase (MetRS), resulting in nucleolar stress, mTORC1 inhibition and, ultimately, autophagy induction. Inhibition of the GCN2-MetRS axis drastically improves the cytotoxicity of RNA polymerase I (RNA pol I) inhibitors, including the first-line chemotherapy oxaliplatin, on patient-derived COAD tumoroids. Our data thus reveal that GCN2 differentially controls ribosome biogenesis according to the nutritional context. Furthermore, pharmacological co-inhibition of the two GCN2 branches and RNA pol I activity may represent a valuable strategy for elimination of proliferative and metabolically stressed COAD cells.

Fiber Microarchitecture in Interpenetrating Collagen-Alginate Hydrogel with Tunable Mechanical Plasticity Regulates Tumor Cell Migration.

The fiber structures of tumor microenvironment (TME) are well-known in regulating tumor cell behaviors, and the plastic remolding of TME has recently been suggested to enhance tumor metastasis as well. However, the interrelationship between the fiber microarchitecture and matrix plasticity is inextricable by existing in vitro models. The individual roles of fiber microarchitecture and matrix plasticity in tuning tumor cell behaviors remain elusive. This study develops an interpenetrating collagen-alginate hydrogel platform with independently tunable matrix plasticity and fiber microarchitecture through an interpenetrating strategy of alginate networks and collagen I networks. With this hydrogel platform, it is demonstrated that tumor cells in high plasticity hydrogels are more extensive and aggressive than in low plasticity hydrogels and fiber structures only have influence in high plasticity hydrogels. The study further elucidates the underlying mechanisms through analyzing the distribution of forces within the matrix and tracking the focal adhesions (FAs) and finds that highly plastic hydrogels can activate the FAs formation, whereas the maturation and stability of FAs are dominated by fiber dispersion. This study not only establishes new ideas on how cells interact with TME cues but also would help to further finely tailor engineered hydrogel platforms for studying tumor behaviors in vitro.

ABCA3, a tumor suppressor gene, inhibits the proliferation, migration and invasion of lung adenocarcinoma by regulating the epithelial‑mesenchymal transition process.

Lung adenocarcinoma (LUAD) is one of the most common types of lung cancer, which affects the life and health of patients. The role of ATP-binding cassette subfamily A member 3 (ABCA3) in the occurrence and development of LUAD is unclear; therefore, ABCA3 expression in LUAD and other tumors was analyzed in the present study. In addition, ABCA3 expression in patients with LUAD and their survival were analyzed using a public database. ABCA3 co-expressed genes were identified and their enriched pathways were analyzed. Furthermore, ABCA3 expression was knocked down in LUAD cell lines. The proliferation, invasion and migration of cells, and the process of epithelial-mesenchymal transition (EMT), were studied through cytological and molecular biology experiments. Compared with that in normal lung tissues, ABCA3 expression was significantly reduced in tumor tissues. Patients with low ABCA3 expression had a markedly worse overall survival compared with those with high ABCA3 expression. Notably, abnormal ABCA3 expression has been observed in a variety of tumors. Subsequently, multiple pathophysiological pathways enriched by ABCA3 and its co-expressed genes were explored. Furthermore, the malignant behavior of tumor cells was enhanced when ABCA3 expression was knocked down, and the EMT process was activated after ABCA3 expression was knocked down. In conclusion, as a tumor suppressor gene, ABCA3 serves a protective role in the development of tumors, and may have a potential role in clinical applications, and thus, is worthy of further study.

On-chip modeling of tumor evolution: Advances, challenges and opportunities.

Tumor evolution is the accumulation of various tumor cell behaviors from tumorigenesis to tumor metastasis and is regulated by the tumor microenvironment (TME). However, the mechanism of solid tumor progression has not been completely elucidated, and thus, the development of tumor therapy is still limited. Recently, Tumor chips constructed by culturing tumor cells and stromal cells on microfluidic chips have demonstrated great potential in modeling solid tumors and visualizing tumor cell behaviors to exploit tumor progression. Herein, we review the methods of developing engineered solid tumors on microfluidic chips in terms of tumor types, cell resources and patterns, the extracellular matrix and the components of the TME, and summarize the recent advances of microfluidic chips in demonstrating tumor cell behaviors, including proliferation, epithelial-to-mesenchymal transition, migration, intravasation, extravasation and immune escape of tumor cells. We also outline the combination of tumor organoids and microfluidic chips to elaborate tumor organoid-on-a-chip platforms, as well as the practical limitations that must be overcome.