Tumor Sphere Research Articles

STEM-04. UNVEILING GLIOBLASTOMA ORIGIN-CELLS: ISOLATION AND CHARACTERIZATION FROM THE SUBVENTRICULAR ZONE

Abstract Glioblastoma (GBM) may originate from somatic mutations within the subventricular zone (SVZ). We investigated putative GBM origin-cells in the SVZ with somatic mutations implicated in GBM development. We hypothesized these origin-cells have unique properties compared to tumor-derived GBM tumorspheres (TSs). We isolated, characterized, and analyzed mouse transcriptomes of GBM origin-cells and GBM TSs, and sought to identify potential human GBM origin-cells within the SVZ. Using a mouse model with somatic mutations (Trp53/Pten/hEGFRvIII) induced within the SVZ, we demonstrated that mutated cells in the SVZ migrate to the cortex and form GBM. We isolated mouse GBM (mGBM) origin-cells from the SVZ and mGBM TSs from the tumors, comparing their characteristics, transcriptome, and tumorigenic potential upon orthotopic or SVZ injection. To identify potential human GBM origin-cells, single-nucleus RNA sequencing (snRNAseq) was performed on human GBM SVZ specimens. Our investigation revealed intriguing properties and distinct gene expression patterns in GBM origin-cells. mGBM origin-cells from the SVZ somatic mutation model demonstrated enhanced stemness and invasiveness compared to control SVZ cells. These cells exhibited site-specific tumorigenic capacity: cortical injection of mGBM origin-cells failed to induce tumor formation, while re-injection into the SVZ led to migration to the cortex and tumor development. RNA sequencing revealed significant gene expression differences between mGBM origin-cells and mGBM TSs despite similar mutation profiles, suggesting distinct identities. snRNAseq analysis of human GBM SVZ specimens (pathologically tumor-free) identified cells with chromosomal aberrations characteristic of early GBM development, including chromosome 7 gain / 10 loss. These findings suggest potential human GBM origin-cells within the SVZ. This study describes a distinct population of GBM origin-cells within the SVZ, different from tumor-derived cancer stem cells. These GBM origin-cells exhibit unique properties, including enhanced stemness and invasiveness, and display site-specific tumorigenic capacity, forming tumors only in the SVZ environment. Further research into the factors that cause GBM origin-cells in the SVZ to migrate and form tumors in the cortex is crucial.

IMMU-10. IDENTIFICATION OF A NEW THERAPEUTIC ANTIGEN FOR GLIOBLASTOMA USING A MONOCLONAL ANTIBODY LIBRARY FROM PATIENT-DERIVED TUMOR SPHERES

Abstract Glioblastoma (GBM) has a poor prognosis despite intensive treatment by surgery, radiation, and chemotherapy, thus new treatment strategies are urgently needed. Various innovative cancer therapies targeting cancer-specific cell surface antigens, such as chimeric antigen receptor T cell therapy, are developed and more cell surface antigens that is highly specific for GBM cells are needed. Although extensive transcriptome analyses or proteomic analysis of GBM cells were performed, few transcripts specific for GBM cells have been identified. However, GBM cell-specific antigen epitopes formed by post-translational modifications of proteins may have been missed by transcriptome or proteomic analysis, and could still be discovered by thoroughly searching for cancer-specific monoclonal antibodies. In this study, we aimed to identify GBM-specific antigens using a monoclonal antibody library from patient-derived tumor spheres, create CAR-T cells against the antigen, and check antitumor efficiency of the CAR-T cells. Approximately 25,000 monoclonal antibody-producing hybridomas were establishment using BALB/c mice and patient derived tumor spheres. Among them, a antibodies that bind to plural glioblastomas and not to plural normal brain cells were selected and we identified the antigen as Prostaglandin F2 receptor negative regulator (PTGFRN) by the expression cloning method. PTGFRN witch is expressed in several cancers regulate migration, angiogenesis, and cell polarity and decreases the radiosensitivity of GBM cells. We created CAR-T cells against the antigen and co-cultured it with GBM cells, which significantly increased the production of IL-2 and INF-γ. Furthermore, the CAR-T cells injected intracranial in an orthotopic xenograft model with patient-derived GBM cells, significantly reduced tumor growth. PTGFRN CAR-T-cell therapy may be a potential novel therapeutic target for GBM.

DDEL-09. AS1411 APTAMER-CONJUGATED NANOSPHERES FOR TARGETING GLIOBLASTOMA THERAPY

Abstract Postoperative chemotherapy remains essential for treating glioblastoma (GBM), with nanocarrier-based drug delivery emerging as the most efficient method. However, non-specific delivery across the blood-brain barrier (BBB) can limit drug accumulation in tumors and cause damage to nearby tissues. As cancer progresses, angiogenic processes lead to the formation of an irregular blood-tumor barrier (BTB), necessitating nanodrug platforms for precise targeting and efficient drug delivery to cancer cells. In this study, we aimed to demonstrate targeted cancer therapy by selectively identifying tumor cells overexpressing nucleolin (NCL) protein using Dox-loaded AS1411 aptamer-conjugated nanospheres. Drug nanocarriers were synthesized from small molecules with sizes ranging from 100 to 300 nm to facilitate drug delivery. Selective drug delivery and cellular uptake were demonstrated for NCL-positive GBM cells (U87 and U251) compared to NCL-negative normal human astrocyte (NHA) cells. Flow cytometric analysis using FAM dye-labeled AS1411 aptamer-conjugated nanospheres confirmed that drug delivery to GBM U87 and U251 cells was actively targeted by specific AS1411-NCL interactions. Confocal laser scanning microscopy and cytotoxicity analysis confirmed that inoculation of Dox-loaded AS1411 aptamer-conjugated nanospheres induced selective internalization in GBM U87 and U251 cells. Moreover, to evaluate cytotoxicity and anti-tumor effects after treatment with PBS, Apt-Nanospheres, Free Dox, and Dox-Apt-Nanospheres, the results were analyzed through cell counting kit (CCK-8) analysis, evaluation of differences in 3D tumor sphere radii, and an in vivo GBM xenograft tumor model. The AS1411 aptamer-conjugated nanosphere drug delivery system was developed for dual-target treatment of GBM. AS1411-mediated specific recognition and drug accumulation significantly enhanced binding to NCL-positive U87 and U251 cells and improved cytotoxicity efficiency compared to Free Dox. Additionally, this study demonstrated that the active targeting model using aptamer-mediated drug delivery was more effective in improving drug penetration and retention in tumor cells than non-specific enhanced permeability and retention (EPR)-mediated delivery and passive drug delivery.

ERO1A levels are a prognostic indicator in EGFR mutated non small cell lung cancer

We have identified endoplasmic reticulum oxidoreductase 1 alpha (ERO1A) as a poor prognostic indicator in epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer (EGFRMUT-NSCLC). In addition, comparison of high versus low ERO1A expression among cohorts of EGFRMUT-NSCLC primary samples revealed that ERO1A expression correlated with increased expression of proteins that regulate secretion. Using the CPTAC proteomic data set in lung adenocarcinoma we found that high ERO1A protein expression correlated with both extracellular matrix and matrix modifying enzymes. In this report, we found that ablating ERO1A expression was a determinant of clonogenicity, tumor sphere formation, spheroid growth and growth in vivo, as well as response to Osimertinib. We validated that ERO1A-knockout EGFRMUT-LUAD cell lines demonstrated a reduction in secretion of both laminin gamma 2 (LAMC2) and the collagen modifying enzyme lysyl oxidase-like 2 (LOXL2). Our work supports the role of ERO1A in modulating the tumor microenvironment that is likely to contribute to tumor progression.

Shikonin Stimulates Mitochondria-Mediated Apoptosis by Enhancing Intracellular Reactive Oxygen Species Production and DNA Damage in Oral Cancer Cells.

Phytotherapy has rendered a new insight towards the treatment of various cancers, including oral cancer with fewer side effects, over the traditional chemotherapeutic drugs to overcome chemoresistance. Shikonin (Shk) is a natural biologically active alkaloid found in the Lithospermum erythrorhizon plant's root. It has potent cytotoxic activities against various cancers. Our study revealed the release time and anticancer potential of Shk on the SCC9 and H357 oral cancer cell lines. We investigated the antiproliferative, antimigratory, cell cycle arresting and apoptosis promoting activity of Shk in oral cancer cells by performing MTT and morphological assay, colony, and tumor sphere formation assay, AO/EtBr and DAPI staining, Annexin V-FITC/PI staining, assay for reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) measurement, comet assay, qRT-PCR, and western blot analysis. We also checked the interaction of DNA and Shk by docking and CD spectroscopy and EtBr displacement assay. As a result, we found that Shk reduced the viability, proliferation, and tumorigenicity of SCC9 and H357 cells in a time and concentration-dependent manner. We obtained half-maximal inhibitory concentration (IC50) at 0.5 µM for SCC9 and 1.25 µM for H357. It promotes apoptosis via overexpressing proapoptotic Bax and caspase 3 via enhancing ROS that leads to MMP depletion and DNA damage and arrests cells at the G2/M & G2/S phase. The antimigratory activity of Shk was performed by analyzing the expression of markers of epithelial-mesenchymal transition like E-cadherin, ZO-1, N-cadherin, and vimentin. These overall results recommended that Shk shows potent anticancer activity against oral cancer cell lines in both in vitro and ex vivo conditions. So, it could be an excellent agent for the treatment of oral cancer.

Suppressing Expression of SERPINE1/PAI1 Through Activation of GPER1 Reduces Progression of Vulvar Carcinoma.

The serine proteinase inhibitor 1 (SERPINE1) gene codes for the plasminogen activator inhibitor 1 (PAI1) protein and is thought to play a tumor supportive role in various cancers. In this work we aimed to uncover the role PAI1 plays in the proliferation, migration, and invasion of vulvar cancer (VC), and define the protein's function as an oncogene or tumor suppressor. Through treatment with an agonist (G1) and antagonist (G36) of G-coupled estrogen receptor 1 (GPER1), an upstream regulator of SERPINE1 expression, and a forward transfection knockdown protocol, the expression of SERPINE1/PAI1 in VC cells was altered. The effects these altered SERPINE1/PAI1 levels had on tumor cell functions were then examined. Proliferation was analyzed using the resazurin assay, while migration was studied via the gap closure assay. Through colony- and tumor sphere- formation assays clonogenicity was tested, and western blots showed protein expression. In A431 VC cells, when the levels of PAI1 were reduced via knockdown or treatment with G1, migration, proliferation, and colony growth was reduced. Treatment with G36 increased expression of PAI1 and increased migration and colony size in CAL39 cells. Based on the findings in this study, suppressing PAI1 expression in VC cells appears to reduce their progression and tumorigenic potential. Therefore, PAI1 could possibly function as an oncogene in VC. GPER1 appears to be a suitable target for suppressing PAI1 in VC.

Synergistic combination of perphenazine and temozolomide suppresses patient-derived glioblastoma tumorspheres.

Glioblastoma (GBM), a primary malignant brain tumor, has a poor prognosis, even with standard treatments such as radiotherapy and chemotherapy. In this study, we explored the anticancer effects of the synergistic combination of perphenazine (PER), a dopamine receptor D2/3 (DRD2/3) antagonist, and temozolomide (TMZ), a standard treatment for GBM, in patient-derived human GBM tumorspheres (TSs). The biological effects of the combination of PER and TMZ in GBM TSs were assessed by measuring cell viability, ATP, stemness, invasiveness, and apoptosis. Changes in protein and mRNA expression were analyzed using western blotting and RNA sequencing. Co-administration of PER and TMZ was evaluated in vivo using a mouse orthotopic xenograft model. The Severance dataset showed that DRD2 and DRD3 expression was higher in tumor tissues than in the tumor-free cortex of patients with GBM. DRD2/3 knockout by CRISPR/Cas9 in patient-derived human GBM TSs inhibited cell growth and ATP production. The combined treatment with PER and TMZ resulted in superior effects on cell viability and ATP assays compared to those in single treatment groups. Flow cytometry, western blotting, and RNA sequencing confirmed elevated apoptosis in GBM TSs following combination treatment. Additionally, the combination of PER and TMZ downregulated the expression of protein and mRNA associated with stemness and invasiveness. In vivo evaluation showed that combining PER and TMZ extended the survival period of the mouse orthotopic xenograft model. The synergistic combination of PER and TMZ has potential as a novel combination treatment strategy for GBM.

CHAC1 blockade suppresses progression of lung adenocarcinoma by interfering with glucose metabolism via hijacking PKM2 nuclear translocation.

Patients with lung adenocarcinoma (LUAD) generally have poor prognosis. Abnormal cellular energy metabolism is a hallmark of LUAD. Glutathione-specific gamma-glutamylcyclotransferase 1 (CHAC1) is a member of the γ-glutamylcyclotransferase family and an unfolded protein response pathway regulatory gene. Its biological function and molecular regulatory mechanism, especially regarding energy metabolism underlying LUAD, remain unclear. By utilizing tissue microarray and data from The Cancer Genome Atlas and Gene Expression Omnibus, we found that CHAC1 expression was markedly higher in LUAD tissues than in non-tumor tissues, and was positively correlated with poor prognosis. Phenotypically, CHAC1 overexpression enhanced the proliferation, migration, invasion, tumor sphere formation, and glycolysis ability of LUAD cells, resulting in tumor growth both in vitro and in vivo. Mechanistically, through a shotgun mass spectrometry-based proteomic approach and high-throughput RNA sequencing, we found that CHAC1 acted as a bridge connecting UBA2 and PKM2, enhancing the SUMOylation of PKM2. The SUMOylated PKM2 then transferred from the cytoplasm to the nucleus, activating the expression of glycolysis-related genes and enhancing the Warburg effect. Lastly, E2F Transcription Factor 1 potently activated CHAC1 transcription by directly binding to the CHAC1 promoter in LUAD cells. The results of this study implied that CHAC1 regulates energy metabolism and promotes glycolysis in LUAD progression.

Investigating SNHG3 as a potential therapeutic approach for HCC stem cells

IntroductionHepatocellular Carcinoma (HCC) is a common malignant tumor worldwide. Long Non-Coding RNA (lncRNA) has gained attention in tumor biology, and this study aims to investigate the role of lncRNA SNHG3 in HCC, specifically in the self-renewal and maintenance of liver cancer stem cells. MethodsThe expression of lncRNA SNHG3 was analyzed in HCC and adjacent normal tissue using the TCGA database. The expression levels of SNHG3 in HCC cell lines (Hep3B, HepG2, Huh7) were detected using qRT-PCR and Western blot techniques. Functional assays, including CCK-8, soft agar colony formation, and tumor sphere formation, were performed to evaluate the impact of SNHG3 on HCC stem cell functionality. MeRIP-qPCR was also used to investigate the regulatory role of SNHG3 in m6A modification of ITGA6 mRNA mediated by METTL3. ResultsThe study found that SNHG3 was significantly upregulated in HCC tissue and cell lines compared to normal liver tissue. SNHG3 expression correlated with the pathological stage, metastasis status, and tumor size of liver cancer. Inhibiting SNHG3 reduced proliferation, colony formation, and tumor sphere formation ability in HCC stem cells. SNHG3 also played a role in regulating the m6A modification and expression of ITGA6 through METTL3. ConclusionThis study emphasizes the upregulation of lncRNA SNHG3 and its role in HCC stem cell self-renewal. SNHG3 may regulate the m6A modification of ITGA6 mRNA through its interaction with METTL3, impacting the function of liver cancer stem cells. These findings support the potential of targeting SNHG3 as a therapeutic approach for HCC.

Oleanolic acid inhibits aldo-keto reductase family 1 member B10-induced cancer stemness and avoids cisplatin-based chemotherapy resistance via the Snail signaling pathway in oral squamous cell carcinoma cell lines

Background/purposeOral squamous cell carcinoma (OSCC) is a common malignancy often associated with poor prognosis due to chemoresistance. In this study, we investigated whether arecoline, a major alkaloid in betel nuts, can stimulate aldo-keto reductase family 1 member B10 (AKR1B10) levels in OSCC, promoting cancer stemness and leading to resistance to cisplatin (CDDP)-based chemotherapy. Materials and methodsGain- and Loss- of AKR1B10 functions were analyzed using WB and q-PCR of OSCC cells. Stemness, epithelial mesenchymal transition (EMT) markers, and CDDP drug resistance in overexpressed AKR1B10 were also identified. ResultsUpregulated AKR1B10 in OSCC significantly increased cell motility and aggregation. The results also showed that the canonical TGF-β1-Smad3 pathway was involved in arecoline-induced AKR1B10 expression, further increasing cancer stemness with CDDP resistance via the Snail-dependent EMT pathway. Moreover, oleanolic acid (OA) and ROS/RNS (reactive oxygen/nitrogen species) inhibitors effectively reversed AKR1B10-induced CDDP-resistance. ConclusionArecoline-induced ROS/RNS to hyper-activate AKR1B10 in tumor sphere cells via the TGF-β1-Smad3 pathway. Furthermore, AKR1B10 enhanced CDDP resistance in OSCC cells via EMT-inducing markers. Finally, Finally, OA may efficiently target CDDP resistance, reverse stemness in OSCC cells, and have the potential as a novel anticancer drug.

Patient-derived xenografts and single-cell sequencing identifies three subtypes of tumor-reactive lymphocytes in uveal melanoma metastases

Uveal melanoma (UM) is a rare melanoma originating in the eye’s uvea, with 50% of patients experiencing metastasis predominantly in the liver. In contrast to cutaneous melanoma, there is only a limited effectiveness of combined immune checkpoint therapies, and half of patients with uveal melanoma metastases succumb to disease within 2 years. This study aimed to provide a path toward enhancing immunotherapy efficacy by identifying and functionally validating tumor-reactive T cells in liver metastases of patients with UM. We employed single-cell RNA-seq of biopsies and tumor-infiltrating lymphocytes (TILs) to identify potential tumor-reactive T cells. Patient-derived xenograft (PDX) models of UM metastases were created from patients, and tumor sphere cultures were generated from these models for co-culture with autologous or MART1-specific HLA-matched allogenic TILs. Activated T cells were subjected to TCR-seq, and the TCRs were matched to those found in single-cell sequencing data from biopsies, expanded TILs, and in livers or spleens of PDX models injected with TILs. Our findings revealed that tumor-reactive T cells resided not only among activated and exhausted subsets of T cells, but also in a subset of cytotoxic effector cells. In conclusion, combining single-cell sequencing and functional analysis provides valuable insights into which T cells in UM may be useful for cell therapy amplification and marker selection.

Patient-derived xenografts and single-cell sequencing identifies three subtypes of tumor-reactive lymphocytes in uveal melanoma metastases.

Uveal melanoma (UM) is a rare melanoma originating in the eye's uvea, with 50% of patients experiencing metastasis predominantly in the liver. In contrast to cutaneous melanoma, there is only a limited effectiveness of combined immune checkpoint therapies, and half of patients with uveal melanoma metastases succumb to disease within 2 years. This study aimed to provide a path toward enhancing immunotherapy efficacy by identifying and functionally validating tumor-reactive T cells in liver metastases of patients with UM. We employed single-cell RNA-seq of biopsies and tumor-infiltrating lymphocytes (TILs) to identify potential tumor-reactive T cells. Patient-derived xenograft (PDX) models of UM metastases were created from patients, and tumor sphere cultures were generated from these models for co-culture with autologous or MART1-specific HLA-matched allogenic TILs. Activated T cells were subjected to TCR-seq, and the TCRs were matched to those found in single-cell sequencing data from biopsies, expanded TILs, and in livers or spleens of PDX models injected with TILs. Our findings revealed that tumor-reactive T cells resided not only among activated and exhausted subsets of T cells, but also in a subset of cytotoxic effector cells. In conclusion, combining single-cell sequencing and functional analysis provides valuable insights into which T cells in UM may be useful for cell therapy amplification and marker selection.

Abstract A077: The role of RhoV in basal-like pancreatic cancer

Abstract Background Pancreatic ductal adenocarcinoma is a devastating disease lacking targeted therapy. Basal-like pancreatic cancer is a tumor subtype with a worse clinical outcome than other subtypes. These cancers are characterized by the expression of basal keratins and mesenchymal markers. However, the genes that drive the basal-like phenotype are poorly understood. Ras homolog family member V (RhoV) is one of the Rho GTPases, and it has been demonstrated to drive the progression of lung and breast cancers. The current study aims to reveal the role of RhoV in basal-like pancreatic cancer. Design RhoV, p63, and CK5/6 were stained in sequential sections by immunohistochemistry. Expression of RhoV in pancreatic cancer and cell lines was reanalyzed based on the data from ProteinAtlas and Broad Insitute DepMap Portal. Basal cell line, BxPC3, and non-basal cell line, Panc1 were selected for functional evaluation based on their differentiated RhoV expression. RhoV gene was overexpressed and knocked down using the CRISPR/gRNA-based Lentiviral system, followed by sphere formation, colony formation, migration, and invasion assays. Results RhoV, p63, and CK5/6 were expressed in the same histologic location of basal pancreatic cancer. The gene expression level of RhoV was co-expressed with p63 (a classic basal marker) in four pancreatic cancer cell lines (broadinstitute.org). Knockout of RhoV by three runs of gRNAs in BxPC3 cells all significantly attenuated tumor sphere formation with less colony formation as compared to mock knockout. Overexpression of RhoV in non-basal-like cells, Panc 1, significantly increased the size of sphere formation, numbers of colony formation, and p38 activation compared to EV control. Cell migration and invasion assays showed the same RhoV-dependent migration and invasion in corresponding cells. Panc1 cells with RhoV knockout significantly generated smaller tumor xenografts in immunodeficient mice and RhoV overexpression led to larger tumor sizes. Conclusion Finding the driver of the basal-like phenotype helps to reveal the pathophysiology of the basal-like subtype of pancreatic cancer and facilitates the identification of new targets for therapeutic purposes. Our preliminary results indicated that RhoV, a small G protein from the Rho family of GTPases, played essential roles in tumor proliferation and progression, by activating the p38 signaling pathway. Further study will be focused on revealing Rhov's downstream pathways and exploring the role of RhoV in apoptosis/cell cycle, cell metabolism, autophagy, etc. in basel-like pancreatic cancer. Citation Format: Shang Wu, Jia Feng, Selina Gao, Ting Wang, Zebang Li, Yifei Liu, Chiung-Kuei Huang, Shaolei Lu. The role of RhoV in basal-like pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A077.

Integrated machine learning algorithms identify KIF15 as a potential prognostic biomarker and correlated with stemness in triple-negative breast cancer

Cancer stem cells (CSCs) have the potential to self-renew and induce cancer, which may contribute to a poor prognosis by enabling metastasis, recurrence, and therapy resistance. Hence, this study was performed to identify the association between CSC-related genes and triple-negative breast cancer (TNBC) development. Stemness gene sets were downloaded from StemChecker. Based on the online databases, a consensus clustering algorithm was conducted for unsupervised classification of TNBC samples. The variations between subtypes were assessed with regard to prognosis, tumor immune microenvironment (TIME), and chemotherapeutic sensitivity. The stemness-related gene signature was established and random survival forest analysis was employed to identify the core gene for validation experiments and tumor sphere formation assays. 499 patients with TNBC were classified into three subgroups and the Cluster 1 had a better OS than others. After that, WGCNA study was performed to identify genes important for Cluster 1 subtype. Out of all 8 modules, the subtype of Cluster 1 and the yellow module with 103 genes demonstrated the largest positive association. After that, a four-gene stemness-related signature was established. Based on the yellow module, the 39 potential pivotal genes were subjected to the random forest survival analysis to find out the gene that was relatively important for OS. KIF15 was confirmed as the targeted gene by LASSO and random survival forest analyses. In vitro experiments, the downregulation of KIF15 promoted the stemness of TNBC cells. The expression levels of stem cell markers Nanog, SOX2, and OCT4 were found to be elevated in TNBC cell lines after KIF15 inhibition. A stemness-associated risk model was constructed to forecast the clinical outcomes of TNBC patients. The downregulation of KIF15 expression in a subpopulation of TNBC stem cells may promote stemness and possibly TNBC progression.

The therapeutic effect of DX2 inhibition in nicotine-induced lung cancer progression

Alternative splicing products of AIMP2 and AIMP2-DX2 (DX2) have been reported to be associated with human lung cancer. In fact, DX2 expression is elevated in human lung cancers and DX2 transgenic mice also develop lung cancer, in particular, Small Cell Lung Cancer (SCLC). However, the mechanism by which DX2 is induced during cancer progression has not been clearly elucidated. Here, we show that DX2 is induced by nicotine, the main component of smoking-related chemicals, which can stabilize the human epidermal growth factor receptor 2 (HER2) protein and transcriptionally increase sonic hedgehog (Shh). Indeed, nicotine showed tumorigenicity via DX2 by promoting spheroid formation and in vivo lung and kidney cancer progression. Moreover, the elimination of DX2 using siRNA or an optimized inhibitor (SNU-14) blocked the induction of HER2, Shh and completely suppressed tumor sphere formation in response to nicotine. These results indicate that DX2 is critical for lung cancer progression, and a specific DX2 inhibitor would be useful for the treatment of human cancers, including SCLC and Non-Small Cell Lung Cancer (NSCLC).

Circ_0008315 promotes tumorigenesis and cisplatin resistance and acts as a nanotherapeutic target in gastric cancer

IntroductionCisplatin-based chemotherapy is one of the fundamental therapeutic modalities for gastric cancer (GC). Chemoresistance to cisplatin is a great clinical challenge, and its underlying mechanisms remain poorly understood. Circular RNAs (circRNAs) are involved in the pathophysiology of multiple human malignancies.MethodsHigh-throughput sequencing was performed to determine the differentially expressed profile of circRNA in GC tissues and cisplatin-resistant GC cells. Quantitative real-time polymerase chain reaction and Fluorescence in situ hybridization was utilized to confirm the dysregulation of circ_0008315 in GC tissues. To evaluate the prognostic significance of circ_0008315 in GC, we used Kaplan-Meier plot. The self-renewal ability of drug-resistant GC cell was verified through tumor sphere formation assay. GC organoids were constructed to simulate the tumor microenvironment and verified the function of circ_0008315 in cisplatin resistance of gastric cancer. In vivo evaluation was conducted using patient-derived xenograft models. Dual-luciferase reporter gene, RNA immunoprecipitation and miRNA pull-down assays were employed to investigate the molecular mechanisms of circ_0008315 in GC.ResultsWe revealed that a novel circRNA hsa_circ_0008315 was upregulated in GC and cisplatin-resistant GC cells. Elevated circ_0008315 was also observed in cisplatin-resistant GC organoid model. High circ_0008315 expression predicted unfavorable survival outcome in GC patients. Downregulation of circ_0008315 expression inhibited proliferation, mobility, and epithelial-mesenchymal transition of GC cells in vitro and in vivo. Reducing circ_0008315 expression in cisplatin-resistant GC organoid model reversed cisplatin resistance. Mechanistically, circ_0008315 modulated the stem cell properties of GC through the miR-3666/CPEB4 signaling pathway, thereby promoting cisplatin resistance and GC malignant progression. Furthermore, we developed PLGA-PEG nanoparticles targeting circ_0008315, and the nanoparticles could effectively inhibit GC proliferation and cisplatin resistance.ConclusionCirc_0008315 exacerbates GC progression and cisplatin resistance, and can be used as a prognostic predictor. Circ_0008315 may function as a promising nanotherapeutic target for GC treatment.Graphical

Modulation of PD-L1 by Astragalus polysaccharide attenuates the induction of melanoma stem cell properties and overcomes immune evasion

BackgroundMelanoma is a highly aggressive form of skin cancer. The existence of cancer stem cells (CSCs) and tumor immune evasion are two major causes of melanoma progression, but no effective treatment has been found at present. Astragalus polysaccharide (APS) is a principal active component derived from Astragalus membranaceus, showing anti-tumor effects in various tumors including melanoma. However, the underlying mechanism is still unclear.MethodsThe regulation of APS on self-renewal ability and CSC markers expression in melanoma stem cells (MSCs) was measured by tumor sphere formation and tumorigenicity assays, RT-qPCR, and western blot. Flow cytometry was conducted to evaluate the activation of immune system by APS in melanoma mice. Further, the mechanism was explored based on PD-L1 overexpression and knock-down B16 cells.ResultsAPS attenuated the tumor sphere formation of MSCs in vitro as well as the tumorigenicity in vivo. It also decreased the expression of CD133, BMI1 and CD47. Based on the PD-L1 overexpression and knock-down B16 cells, it was confirmed that APS inhibited the induction of MSCs by down-regulating PD-L1 expression. Meanwhile, APS increased the infiltration of CD4+ and CD8+T cells in tumor tissues because of its inhibitory effect on PD-L1.ConclusionsAPS inhibited MSC induction and overcame tumor immune evasion through reducing PD-L1 expression. This study provided compelling evidence that APS could be a prospective therapeutic agent for treating melanoma.

Integrin αV Inhibition by GMI, a Ganoderma Microsporum Immunomodulatory Protein, Abolish Stemness and Migration in EGFR-Mutated Lung Cancer Cells Resistant to Osimertinib.

Integrins, the receptors of the extracellular matrix, are critical in the proliferation and metastasis of cancer cells. GMI, a Ganoderma microsporum immunomodulatory protein, possesses anticancer and antivirus abilities. The object of this study is to investigate the role of GMI in the integrins signaling pathway in lung cancer cells that harbor the EGFR L858R/T790M double mutation and osimertinib-resistance. Liquid chromatography-mass spectrometry and western blot assay were used to investigate the effect of GMI on inhibiting the protein expressions of integrins in H1975 cells. The migration ability and xenograft tumor growth of H1975 were suppressed by GMI. To elucidate the role of the integrin family in lung cancer resistant to osimertinib (AZD-9291, Tagrisso), H1975 cells were used to establish the osimertinib-resistant cells, named H1975/TR cells. The expressions of Integrin αV and stemness markers were much higher in H1975/TR cells than in H1975 cells. GMI suppressed cell viability, tumor spheroid growth, and the expressions of integrin αV and β1 in H1975/TR cells. Furthermore, GMI suppressed the expressions of stemness markers and formation of tumor spheres via blocking integrin αV signaling cascade. This is the first study to reveal the novel function of GMI in constraining cancer stem cells and migration by abolishing the integrin αV-related signaling pathway in EGFR-mutated and osimertinib-resistant lung cancer cells.

TsRNA-GlyGCC promotes colorectal cancer progression and 5-FU resistance by regulating SPIB

BackgroundtRNA-derived small RNAs (tsRNAs) are newly discovered non-coding RNA, which are generated from tRNAs and are reported to participate in several biological processes in diseases, especially cancer; however, the mechanism of tsRNA involvement in colorectal cancer (CRC) and 5-fluorouracil (5-FU) is still unclear.MethodsRNA sequencing was performed to identify differential expression of tsRNAs in CRC tissues. CCK8, colony formation, transwell assays, and tumor sphere assays were used to investigate the role of tsRNA-GlyGCC in 5-FU resistance in CRC. TargetScan and miRanda were used to identify the target genes of tsRNA-GlyGCC. Biotin pull-down, RNA pull-down, luciferase assay, ChIP, and western blotting were used to explore the underlying molecular mechanisms of action of tsRNA-GlyGCC. The MeRIP assay was used to investigate the N(7)-methylguanosine RNA modification of tsRNA-GlyGCC.ResultsIn this study, we uncovered the feature of tsRNAs in human CRC tissues and confirmed a specific 5’ half tRNA, 5’tiRNA-Gly-GCC (tsRNA-GlyGCC), which is upregulated in CRC tissues and modulated by METTL1-mediated N(7)-methylguanosine tRNA modification. In vitro and in vivo experiments revealed the oncogenic role of tsRNA-GlyGCC in 5-FU drug resistance in CRC. Remarkably, our results showed that tsRNA-GlyGCC modulated the JAK1/STAT6 signaling pathway by targeting SPIB. Poly (β-amino esters) were synthesized to assist the delivery of 5-FU and tsRNA-GlyGCC inhibitor, which effectively inhibited tumor growth and enhanced CRC sensitive to 5-FU without obvious adverse effects in subcutaneous tumor.ConclusionsOur study revealed a specific tsRNA-GlyGCC-engaged pathway in CRC progression. Targeting tsRNA-GlyGCC in combination with 5-FU may provide a promising nanotherapeutic strategy for the treatment of 5-FU-resistance CRC.Graphical

Hypermethylated RASAL1’s promotive role in chemoresistance and tumorigenesis of choriocarcinoma was regulated by TET2 but not DNMTs

BackgroundPatients with choriocarcinoma (CC) accompanying chemoresistance conventionally present a poor prognosis. Whether ras protein activator like-1 (RASAL1) functions as a tumor promoter or suppressor depends on tumor types. However, the role of RASAL1 in process of chemoresistance of CC and underlying molecular mechanism remain elusive.MethodsThe expression pattern of RASAL1 in CC cells and tissues was measured using Western blotting, immunohistochemistry and qRT-PCR. Cell viability and proliferative ability were assessed by MTT assay, Tunnel assay and flow cytometric analysis. Additionally, the stemness was evaluated by the colony formation and tumor sphere formation. Methotrexate (MTX) was applied to exam the chemosensitivity of CC cells.ResultsThe expression of RASAL1 was reduced both at the protein and mRNA levels in CC tissues and cells compared to hydatidiform mole (HM) and invasive mole (IM). Loss of RASAL1 was attributed to its promoter hypermethylation and could be restored by 5-Aza. Knock-down of RASAL1 promoted the viability, proliferative potential, stemness and EMT phenotype of JEG-3 cells. However, induced overexpression of RASAL1 by 5-Aza significantly prohibited cell proliferation and stemness potential of the JAR cell. Additionally, the xenograft model indicated that knockdown of RASAL1 led to a remarkable increase of tumor volume and weight in comparison with its counterpart. Moreover, the stimulatory activity brought by decrease of RASAL1 could be deprived by β-catenin inhibitor XAV 939, yet the suppressive activity resulted from its promoter demethylation could be rescued by β-catenin activator BML-284, indicating that function of RASAL1 depends on β-catenin. Besides, the co-immunoprecipitation assay confirmed the physical binding between RASAL1 and β-catenin. Further investigations showed hypermethylated RASAL1 was regulated by TET2 but not DNMTs.ConclusionTaken together, the present data elucidated that reduced RASAL1 through its promoter hypermethylation regulated by TET2 promoted the tumorigenicity and chemoresistance of CC via modulating β-catenin both in vitro and in vivo.