Promotes Tumor Cell Proliferation Research Articles

Role of INPP4B in the proliferation, migration, invasion, and survival of human endometrial cancer cells.

Inositol polyphosphate 4-phosphatase type II (INPP4B) has been identified as a tumor repressor in several human cancers while its role in endometrial cancer has not been investigated yet. Therefore, the current study was designed to determine whether INPP4B participates in the progression of endometrial cancer by utilizing clinical data and experimental determination. We first include six chemotherapy-treated patients with recurrent and metastatic endometrioid carcinoma to determine the relationship between INPP4B mutation and relative tumor burden. By using siRNA-mediated gene silencing and vector-mediated gene overexpression, we further determined the effect of manipulating INPP4B expression on the proliferation, invasion, and survival of endometrial cancer cells. Furthermore, the repressing effect of INPP4B together with its role in chemotherapy was further validated by xenograft tumor-bearing mice models. Western blot analysis was used to explore further downstream signaling modulated by INPP4B expression manipulation. Two of the patients were found to have INPP4B mutations and the mutation frequency of INPP4B increased during the progression of chemotherapy resistance. Endometrial cancer cells with silenced INPP4B expression were found to have promoted tumor cell proliferation, invasion, and survival. Endometrial cancer cells overexpressing INPP4B were found to have decreased tumor cell proliferation, invasion, and survival. An in vivo study using six xenograft tumor-bearing mice in each group revealed that INPP4B overexpression could suppress tumor progression and enhance chemosensitivity. Furthermore, INPP4B overexpression was found to modulate the activation of Wnt3a signaling. The current study suggested that INPP4B could be a suppressor in endometrial cancer progression and might be a target for endometrial cancer treatment. Also, INPP4B might serve as a predictor of chemosensitivity determination.

GluOC promotes proliferation and metastasis of TNBC through the ROCK1 signaling pathway

BackgroundTriple negative breast cancer (TNBC) is a type of breast cancer that is negative for oestrogen receptor, progesterone receptor and human epidermal growth factor receptor 2, is highly malignant and aggressive, lacks of corresponding targeted therapy, and has a relatively poor prognosis. Therefore, understanding the mechanism of TNBC development and formulating effective treatment strategies for inducing cell death are still urgent tasks in the treatment of TNBC. Research has shown that uncarboxylated osteocalcin can promote the proliferation of prostate cancer, lung adenocarcinoma and TNBC cells, but the mechanism by which GluOC affects TNBC growth and metastasis needs further study.MethodsMDA-MB-231 breast cancer cells were used for in vitro cell analysis. Key target molecules or pathways were identified by RNA sequencing, and migration ability was detected by scratch assays, Transwell assays, cell adhesion assays and western blot analysis. Fluorescence staining, colony detection, qRT‒PCR and flow cytometry were used to detect apoptosis, oxidative stress, the cell cycle and the stemness of cancer cells, and a xenotransplantation model in BALB/C nude mice was used for in vivo analysis.ResultsThis study demonstrated that GluOC facilitates the migration of MDA-MB-231 breast cancer cells through the ROCK1/MYPT1/MLC2 signalling pathway and promotes the proliferation of TNBC cells via the ROCK1/JAK2/PIK3CA/AKT signalling pathway. Experiments in nude mice demonstrated that GluOC promoted tumour cell proliferation and metastasis in tumour-bearing mice, which further clarified the molecular mechanism of TNBC growth and invasion.ConclusionOur findings highlight the importance of GluOC in driving TNBC progression and its association with poor patient outcomes. This study clarifies the functional effects of GluOC on TNBC growth, providing insight into the molecular basis of TNBC and potentially providing new ideas for developing targeted therapies to improve patient outcomes.

Development of a Pyrone-Fused Tricyclic Scaffold-based Ratiometric Fluorescent Probe for Al3+ Detection.

Aluminum (Al3+) is environmentally abundant and can harm living organisms in various ways, such as by inhibiting root growth, damaging faunal nervous systems, and promoting tumor cell proliferation. However, the dynamics of Al3+ in living organisms are largely unknown; thus, detecting Al3+ in the environment and organisms is crucial. Fluorescent probes are useful tools for the selective detection of metal ions. In particular, ratiometric fluorescent probes exhibit a detection response at two different maximum fluorescence emission wavelengths; which is advantageous for avoiding the influence of background fluorescence. A novel pyrone-fused tricyclic scaffold-based ratiometric fluorescent probe for detecting Al3+, ethyl 11-imino-1-oxo-3-phenyl-1H,11H-pyrano[4,3-b] quinolizine-5-carboxylate (PQ), was developed in this study. The PQ fluorescence blue shifted from 505 to 457nm upon the addition of Al3+. The blue shift was accompanied by a change in the fluorescence color of the PQ solution from green to blue. Fluorescence titration experiments demonstrated that the fluorescence intensity ratio at the two peaks of interest (457/505nm) increased in a concentration-dependent manner upon the addition of Al3+. Moreover, this study demonstrated that a PQ-soaked paper displays a visible color change under ultraviolet light upon exposure to Al3+. The above results suggest that PQ is an effective ratiometric probe for the detection of Al3+ in the environment. Future studies will be conducted to introduce various substituents and develop fluorescent probes by leveraging the fluorescence property of a pyrone-fused tricyclic scaffolds.

Impact of Genomic Mutation on Melanoma Immune Microenvironment and IFN-1 Pathway-Driven Therapeutic Responses.

The BRAFV600E mutation, found in approximately 50% of melanoma cases, plays a crucial role in the activation of the MAPK/ERK signaling pathway, which promotes tumor cell proliferation. This study aimed to evaluate its impact on the melanoma immune microenvironment and therapeutic responses, particularly focusing on immunogenic cell death (ICD), a pivotal cytotoxic process triggering anti-tumor immune responses. Through comprehensive in silico analysis of the Cancer Genome Atlas data, we explored the association between the BRAFV600E mutation, immune subtype dynamics, and tumor mutation burden (TMB). Our findings revealed that the mutation correlated with a lower TMB, indicating a reduced generation of immunogenic neoantigens. Investigation into immune subtypes reveals an exacerbation of immunosuppression mechanisms in BRAFV600E-mutated tumors. To assess the response to ICD inducers, including doxorubicin and Me-ALA-based photodynamic therapy (PDT), compared to the non-ICD inducer cisplatin, we used distinct melanoma cell lines with wild-type BRAF (SK-MEL-2) and BRAFV600E mutation (SK-MEL-28, A375). We demonstrated a differential response to PDT between the WT and BRAFV600E cell lines. Further transcriptomic analysis revealed upregulation of IFNAR1, IFNAR2, and CXCL10 genes associated with the BRAFV600E mutation, suggesting their involvement in ICD. Using a gene reporter assay, we showed that PDT robustly activated the IFN-1 pathway through cGAS-STING signaling. Collectively, our results underscore the complex interplay between the BRAFV600E mutation and immune responses, suggesting a putative correlation between tumors carrying the mutation and their responsiveness to therapies inducing the IFN-1 pathway, such as the ICD inducer PDT, possibly mediated by the elevated expression of IFNAR1/2 receptors.

Multi-Omics Characterization of E3 Regulatory Patterns in Different Cancer Types.

Ubiquitination, a post-translational modification, refers to the covalent attachment of ubiquitin molecules to substrates. This modification plays a critical role in diverse cellular processes such as protein degradation. The specificity of ubiquitination for substrates is regulated by E3 ubiquitin ligases. Dysregulation of ubiquitination has been associated with numerous diseases, including cancers. In our study, we first investigated the protein expression patterns of E3 ligases across 12 cancer types. Our findings indicated that E3 ligases tend to be up-regulated and exhibit reduced tissue specificity in tumors. Moreover, the correlation of protein expression between E3 ligases and substrates demonstrated significant changes in cancers, suggesting that E3-substrate specificity alters in tumors compared to normal tissues. By integrating transcriptome, proteome, and ubiquitylome data, we further characterized the E3-substrate regulatory patterns in lung squamous cell carcinoma. Our analysis revealed that the upregulation of the SKP2 E3 ligase leads to excessive degradation of BRCA2, potentially promoting tumor cell proliferation and metastasis. Furthermore, the upregulation of E3 ubiquitin-protein ligase TRIM33 was identified as a biomarker associated with a favorable prognosis by inhibiting the cell cycle. This work exemplifies how leveraging multi-omics data to analyze E3 ligases across various cancers can unveil prognosis biomarkers and facilitate the identification of potential drug targets for cancer therapy.

Peptidyl-prolyl isomerase F as a prognostic biomarker associated with immune infiltrates and mitophagy in lung adenocarcinoma.

Lung adenocarcinoma (LUAD) is among the most prevalent malignancies worldwide, with unfavorable treatment outcomes. Peptidyl-prolyl isomerase F (PPIF) is known to influence the malignancy traits of tumor progression by modulating the bioenergetics and mitochondrial permeability in cancer cells; however, its role in LUAD remains unclear. Our study seeks to investigate the clinical significance, tumor proliferation, and immune regulatory functions of PPIF in LUAD. The expression of PPIF in LUAD tissues and cells was assessed using bioinformatics analysis, immunohistochemistry (IHC), and Western blotting. Survival curve analysis was conducted to examine the prognostic association between PPIF expression and LUAD. The immunomodulatory role of PPIF in LUAD was assessed through the analysis of PPIF expression and immune cell infiltration. A series of gain- and loss-of-function experiments were conducted on PPIF to investigate its biological functions in LUAD both in vitro and in vivo. The mechanisms underlying PPIF's effects on LUAD were delineated through functional enrichment analysis and Western blotting assays. PPIF exhibited overexpression in LUAD tissues compared to normal controls. Survival curve analysis revealed that patients with LUAD exhibiting higher PPIF expression demonstrated decreased overall survival and a shorter progression-free interval. PPIF was implicated in modulating immune cell infiltration, particularly in regulating the T helper 1-T helper 2 cell balance. Functionally, PPIF was discovered to promote tumor cell proliferation and advance cell-cycle progression. Furthermore, PPIF could impede mitophagy by targeting the FOXO3a/PINK1-Parkin signaling pathway. The findings of this study indicate that the prognosis-related gene PPIF may have a significant role in the regulation of LUAD cell proliferation, tumor-associated immune cell infiltration, and mitophagy, and thus PPIF may be a promising therapeutic target of LUAD.

BAG6 restricts pancreatic cancer progression by suppressing the release of IL33-presenting extracellular vesicles and the activation of mast cells

Recent studies reveal a critical role of tumor cell-released extracellular vesicles (EVs) in pancreatic cancer (PC) progression. However, driver genes that direct EV function, the EV-recipient cells, and their cellular response to EV uptake remain to be identified. Therefore, we studied the role of Bcl-2-associated-anthanogene 6 (BAG6), a regulator of EV biogenesis for cancer progression. We used a Cre recombinase/LoxP-based reporter system in combination with single-cell RNA sequencing to monitor in vivo EV uptake and tumor microenvironment (TME) changes in mouse models for pancreatic ductal adenocarcinoma (PDAC) in a Bag6 pro- or deficient background. In vivo data were validated using mouse and human organoids and patient samples. Our data demonstrated that Bag6-deficient subcutaneous and orthotopic PDAC tumors accelerated tumor growth dependent on EV release. Mechanistically, this was attributed to mast cell (MC) activation via EV-associated IL33. Activated MCs promoted tumor cell proliferation and altered the composition of the TME affecting fibroblast polarization and immune cell infiltration. Tumor cell proliferation and fibroblast polarization were mediated via the MC secretome containing high levels of PDGF and CD73. Patients with high BAG6 gene expression and high protein plasma level have a longer overall survival indicating clinical relevance. The current study revealed a so far unknown tumor-suppressing activity of BAG6 in PDAC. Bag6-deficiency allowed the release of EV-associated IL33 which modulate the TME via MC activation promoting aggressive tumor growth. MC depletion using imatinib diminished tumor growth providing a scientific rationale to consider imatinib for patients stratified with low BAG6 expression and high MC infiltration.EVs derived from BAG6-deficient pancreatic cancer cells induce MC activation via IL33/Il1rl1. The secretome of activated MCs induces tumor proliferation and changes in the TME, particularly shifting fibroblasts into an inflammatory cancer-associated fibroblast (iCAF) phenotype. Blocking EVs or depleting MCs restricts tumor growth.

Selective nitration of Hsp90 acts as a metabolic switch promoting tumor cell proliferation

Tumors develop in an oxidative environment characterized by peroxynitrite production and downstream protein tyrosine (Y) nitration. We showed that tyrosine nitration supports schwannoma cell proliferation and regulates cell metabolism in the inheritable tumor disorder NF2-related Schwannomatosis (NF2-SWN). Here, we identified the chaperone Heat shock protein 90 (Hsp90) as the first nitrated protein that acts as a metabolic switch to promote schwannoma cell proliferation. Doubling the endogenous levels of nitrated Hsp90 in schwannoma cells or supplementing nitrated Hsp90 into normal Schwann cells increased their proliferation. Metabolically, nitration on either Y33 or Y56 conferred Hsp90 distinct functions; nitration at Y33 (Hsp90NY33) down-regulated mitochondrial oxidative phosphorylation, while nitration at Y56 (Hsp90NY56) increased glycolysis by activating the purinergic receptor P2X7 in both schwannoma and normal Schwann cells. Hsp90NY33 and Hsp90NY56 showed differential subcellular and spatial distribution corresponding with their metabolic and proliferative functions in schwannoma three-dimensional cell culture models. Collectively, these results underscore the role of tyrosine nitration as a post-translational modification regulating critical cellular processes. Nitrated proteins, particularly nitrated Hsp90, emerge as a novel category of tumor-directed therapeutic targets.

The RNF214-TEAD-YAP signaling axis promotes hepatocellular carcinoma progression via TEAD ubiquitylation

RNF214 is an understudied ubiquitin ligase with little knowledge of its biological functions or protein substrates. Here we show that the TEAD transcription factors in the Hippo pathway are substrates of RNF214. RNF214 induces non-proteolytic ubiquitylation at a conserved lysine residue of TEADs, enhances interactions between TEADs and YAP, and promotes transactivation of the downstream genes of the Hippo signaling. Moreover, YAP and TAZ could bind polyubiquitin chains, implying the underlying mechanisms by which RNF214 regulates the Hippo pathway. Furthermore, RNF214 is overexpressed in hepatocellular carcinoma (HCC) and inversely correlates with differentiation status and patient survival. Consistently, RNF214 promotes tumor cell proliferation, migration, and invasion, and HCC tumorigenesis in mice. Collectively, our data reveal RNF214 as a critical component in the Hippo pathway by forming a signaling axis of RNF214-TEAD-YAP and suggest that RNF214 is an oncogene of HCC and could be a potential drug target of HCC therapy.

The deubiquitinase USP2a promotes tumor immunosuppression by stabilizing immune checkpoint B7–H4 in lung adenocarcinoma harboring EGFR-activating mutants

B7–H4 is an immune checkpoint crucial for inhibiting CD8+ T-cell activity. A clinical trial is underway to investigate B7–H4 as a potential immunotherapeutic agent. However, the regulatory mechanism of B7–H4 degradation via the ubiquitin-proteasome pathway (UPP) remains poorly understood. In this study, we discovered that proteasome inhibitors effectively increased B7–H4 expression, while EGFR-activating mutants promoted B7–H4 expression through the UPP. We screened B7–H4 binding proteins by co-immunoprecipitation and mass spectrometry and found that USP2a acted as a deubiquitinase of B7–H4 by removing K48- and K63-linked ubiquitin chains from B7–H4, leading to a reduction in B7–H4 degradation. EGFR mutants enhanced B7–H4 stability by upregulating USP2a expression. We further investigated the role of USP2a in tumor growth in vivo. Depletion of USP2a in L858R/LLC cells inhibited tumor cell proliferation, consequently suppressing tumor growth in immune-deficient nude mice by destabilizing downstream molecules such as Cyclin D1. In an immune-competent C57BL/6 mouse tumor model, USP2a abrogation facilitated infiltration of CD95+CD8+ effector T cells and hindered infiltration of Tim-3+CD8+ and LAG-3+CD8+ exhausted T cells by destabilizing B7–H4. Clinical lung adenocarcinoma samples showed a significant correlation between B7–H4 abundance and USP2a expression, indicating the contribution of the EGFR/USP2a/B7–H4 axis to tumor immunosuppression. In summary, this study elucidates the dual effects of USP2a in tumor growth by stabilizing Cyclin D1, promoting tumor cell proliferation, and stabilizing B7–H4, contributing to tumor immunosuppression. Therefore, USP2a represents a potential target for tumor therapy.

CSE1L as a prognostic biomarker associated with pan cancer immune infiltration and drug sensitivity

ABSTRACT Background Rising cancer-related mortality underscores the importance of biomarkers for treatment and prognosis, with Chromosome Segregation 1 Like (CSE1L) linked to various cancers yet its roles remain partially understood. This study investigates CSE1L’s expression and oncogenic mechanisms in solid tumors. Research design and methods We analyzed multi-omics data from 31 solid tumors, measured CSE1L in 41 head and neck carcinoma patients post-chemotherapy via qRT-PCR, and evaluated the impact of CSE1L knockdown on cell proliferation in A549 and HepG2 cells. Results In this study, we observed significantly elevated levels of CSE1L RNA in 13 tumor tissues and protein levels in 8 tumor tissues compared to their corresponding adjacent normal tissues. Additionally, our investigation unveiled a correlation between heightened CSE1L expression in tumor tissues and worsened patient prognosis, poor response to immunotherapy, and diminished effectiveness of neoadjuvant chemotherapy. Through an analysis of CSE1L mechanisms, we discovered its potential involvement in promoting tumor cell proliferation, enhancing drug resistance, and influencing immune infiltration, thereby impacting patient prognosis and treatment outcomes. Finally, we delved into the potential mechanisms underlying upregulation of CSE1L in tumor tissues. Conclusion Our findings demonstrate that CSE1L promotes tumor development in various malignancies, highlighting its potential as both a therapeutic target and prognostic indicator.

APC/C-regulated CPT1C promotes tumor progression by upregulating the energy supply and accelerating the G1/S transition

BackgroundIn addition to functioning as a precise monitoring mechanism in cell cycle, the anaphase-promoting complex/cyclosome (APC/C) is reported to be involved in regulating multiple metabolic processes by facilitating the ubiquitin-mediated degradation of key enzymes. Fatty acid oxidation is a metabolic pathway utilized by tumor cells that is crucial for malignant progression; however, its association with APC/C remains to be explored.MethodsCell cycle synchronization, immunoblotting, and propidium iodide staining were performed to investigate the carnitine palmitoyltransferase 1 C (CPT1C) expression manner. Proximity ligation assay and co-immunoprecipitation were performed to detect interactions between CPT1C and APC/C. Flow cytometry, 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2 H-tetrazolium, inner salt (MTS) assays, cell-scratch assays, and transwell assays and xenograft transplantation assays were performed to investigate the role of CPT1C in tumor progression in vitro and in vivo. Immunohistochemistry was performed on tumor tissue microarray to evaluate the expression levels of CPT1C and explore its potential clinical value.ResultsWe identified CPT1C as a novel APC/C substrate. CPT1C protein levels exhibited cell cycle-dependent fluctuations, peaking at the G1/S boundary. Elevated CPT1C accelerated the G1/S transition, facilitating tumor cell proliferation in vitro and in vivo. Furthermore, CPT1C enhanced fatty acid utilization, upregulated ATP levels, and decreased reactive oxygen species levels, thereby favoring cell survival in a harsh metabolic environment. Clinically, high CPT1C expression correlated with poor survival in patients with esophageal squamous cell carcinoma.ConclusionsOverall, our results revealed a novel interplay between fatty acid utilization and cell cycle machinery in tumor cells. Additionally, CPT1C promoted tumor cell proliferation and survival by augmenting cellular ATP levels and preserving redox homeostasis, particularly under metabolic stress. Therefore, CPT1C could be an independent prognostic indicator in esophageal squamous cell carcinoma.

An E3 ligase TRIM1 promotes colorectal cancer progression via K63-linked ubiquitination and activation of HIF1α

Accumulating studies have shown that E3 ligases play crucial roles in regulating cellular biological processes and signaling pathways during carcinogenesis via ubiquitination. Tripartite-motif (TRIM) ubiquitin E3 ligases consist of over 70 members. However, the clinical significance and their contributions to tumorigenesis remain largely unknown. In this study, we analyzed the RNA-sequencing expression of TRIM E3 ligases in colorectal cancer (CRC) and identified 10 differentially expressed genes, among which TRIM1 expression predicted poor prognosis of CRC patients. We demonstrated that TRIM1 expression is positively associated with CRC pathological stages, and higher expression is positively correlated with infiltrating levels of immune cells and immunotherapy biomarkers. TRIM1 expression promotes the proliferation and migration of colorectal cancer cells in vitro and in vivo. Transcriptional analysis showed that TRIM1 is responsible for metabolism promotion and immune suppression. Mechanistically, we found that TRIM1 binds HIF1α and mediates its K63-linked ubiquitination, which is required for HIF1α nuclear translocation and subsequent activation. Ubiquitination occurs at Lys214 in the loop between the two PAS domains of HIF1α, and mutation of Lys214 severely disturbs the function of HIF1α. Besides, HIF1α ubiquitination enhances its binding with proteins involved in cellular trafficking and nucleocytoplasmic transport pathway. Collectively, our results indicate TRIM1’s role in predicting prognosis and reveal how TRIM1 functions to upregulate HIF1α expression and promote tumor cell proliferation.

Small-Molecule Inhibitors of TIPE3 Protein Identified through Deep Learning Suppress Cancer Cell Growth In Vitro.

Tumor necrosis factor-α-induced protein 8-like 3 (TNFAIP8L3 or TIPE3) functions as a transfer protein for lipid second messengers. TIPE3 is highly upregulated in several human cancers and has been established to significantly promote tumor cell proliferation, migration, and invasion and inhibit the apoptosis of cancer cells. Thus, inhibiting the function of TIPE3 is expected to be an effective strategy against cancer. The advancement of artificial intelligence (AI)-driven drug development has recently invigorated research in anti-cancer drug development. In this work, we incorporated DFCNN, Autodock Vina docking, DeepBindBC, MD, and metadynamics to efficiently identify inhibitors of TIPE3 from a ZINC compound dataset. Six potential candidates were selected for further experimental study to validate their anti-tumor activity. Among these, three small-molecule compounds (K784-8160, E745-0011, and 7238-1516) showed significant anti-tumor activity in vitro, leading to reduced tumor cell viability, proliferation, and migration and enhanced apoptotic tumor cell death. Notably, E745-0011 and 7238-1516 exhibited selective cytotoxicity toward tumor cells with high TIPE3 expression while having little or no effect on normal human cells or tumor cells with low TIPE3 expression. A molecular docking analysis further supported their interactions with TIPE3, highlighting hydrophobic interactions and their shared interaction residues and offering insights for designing more effective inhibitors. Taken together, this work demonstrates the feasibility of incorporating deep learning and MD simulations in virtual drug screening and provides inhibitors with significant potential for anti-cancer drug development against TIPE3-.

AMD1 promotes breast cancer aggressiveness via a spermidine-eIF5A hypusination-TCF4 axis

BackgroundBasal-like breast cancer (BLBC) is the most aggressive subtype of breast cancer due to its aggressive characteristics and lack of effective therapeutics. However, the mechanism underlying its aggressiveness remains largely unclear. S-adenosylmethionine decarboxylase proenzyme (AMD1) overexpression occurs specifically in BLBC. Here, we explored the potential molecular mechanisms and functions of AMD1 promoting the aggressiveness of BLBC.MethodsThe potential effects of AMD1 on breast cancer cells were tested by western blotting, colony formation, cell proliferation assay, migration and invasion assay. The spermidine level was determined by high performance liquid chromatography. The methylation status of CpG sites within the AMD1 promoter was evaluated by bisulfite sequencing PCR. We elucidated the relationship between AMD1 and Sox10 by ChIP assays and quantitative real-time PCR. The effect of AMD1 expression on breast cancer cells was evaluated by in vitro and in vivo tumorigenesis model.ResultsIn this study, we showed that AMD1 expression was remarkably elevated in BLBC. AMD1 copy number amplification, hypomethylation of AMD1 promoter and transcription activity of Sox10 contributed to the overexpression of AMD1 in BLBC. AMD1 overexpression enhanced spermidine production, which enhanced eIF5A hypusination, activating translation of TCF4 with multiple conserved Pro-Pro motifs. Our studies showed that AMD1-mediated metabolic system of polyamine in BLBC cells promoted tumor cell proliferation and tumor growth. Clinically, elevated expression of AMD1 was correlated with high grade, metastasis and poor survival, indicating poor prognosis of breast cancer patients.ConclusionOur work reveals the critical association of AMD1-mediated spermidine-eIF5A hypusination-TCF4 axis with BLBC aggressiveness, indicating potential prognostic indicators and therapeutic targets for BLBC.

The role of CXCL2-mediated crosstalk between tumor cells and macrophages in Fusobacterium nucleatum-promoted oral squamous cell carcinoma progression

Dysbiosis of the oral microbiota is related to chronic inflammation and carcinogenesis. Fusobacterium nucleatum (Fn), a significant component of the oral microbiota, can perturb the immune system and form an inflammatory microenvironment for promoting the occurrence and progression of oral squamous cell carcinoma (OSCC). However, the underlying mechanisms remain elusive. Here, we investigated the impacts of Fn on OSCC cells and the crosstalk between OSCC cells and macrophages. 16 s rDNA sequencing and fluorescence in situ hybridization verified that Fn was notably enriched in clinical OSCC tissues compared to paracancerous tissues. The conditioned medium co-culture model validated that Fn and macrophages exhibited tumor-promoting properties by facilitating OSCC cell proliferation, migration, and invasion. Besides, Fn and OSCC cells can recruit macrophages and facilitate their M2 polarization. This crosstalk between OSCC cells and macrophages was further enhanced by Fn, thereby amplifying this positive feedback loop between them. The production of CXCL2 in response to Fn stimulation was a significant mediator. Suppression of CXCL2 in OSCC cells weakened Fn’s promoting effects on OSCC cell proliferation, migration, macrophage recruitment, and M2 polarization. Conversely, knocking down CXCL2 in macrophages reversed the Fn-induced feedback effect of macrophages on the highly invasive phenotype of OSCC cells. Mechanistically, Fn activated the NF-κB pathway in both OSCC cells and macrophages, leading to the upregulation of CXCL2 expression. In addition, the SCC7 subcutaneous tumor-bearing model in C3H mice also substantiated Fn’s ability to enhance tumor progression by facilitating cell proliferation, activating NF-κB signaling, up-regulating CXCL2 expression, and inducing M2 macrophage infiltration. However, these effects were reversed by the CXCL2-CXCR2 inhibitor SB225002. In summary, this study suggests that Fn contributes to OSCC progression by promoting tumor cell proliferation, macrophage recruitment, and M2 polarization. Simultaneously, the enhanced CXCL2-mediated crosstalk between OSCC cells and macrophages plays a vital role in the pro-cancer effect of Fn.

Abstract 4665: USP18 promotes anlotinib resistance in medullary thyroid carcinoma by stabilizing aurora B kinase

Abstract Targeted therapy resistance is the main cause of disease progression in advanced medullary thyroid carcinoma (MTC). However, the key molecules and mechanisms remain unclear. We previously performed a genome-wide in vitro screen of Anlotinib resistance-related genes in human MTC cell line TT using CRISPR-dCas9-SAM system and identified ubiquitin-specific protease 18 (USP18) as a key molecule mediating Anlotinib resistance in MTC. However, its downstream mechanism needs further clarification. Based on the high-throughput DNA sequencing results of the control group and the Anlotinib screening group, a group of key genes related to Anlotinib resistance in MTC was screened through the MAGeCK algorithm and the enrichment ratio of sgRNA in the Anlotinib screening group. Among them, USP18 ranked first in the enrichment results. Analysis of the correlation between the expression level of USP18 in MTC patient specimens and survival revealed that patients with high USP18 expression in tumor cells had poorer prognosis. Overexpression of USP18 in MTC tumor cells significantly promoted the growth of subcutaneous xenograft tumors in NOD/SCID mice treated with Anlotinib. In vitro cell experiments also showed that overexpression of USP18 promoted the proliferation of MTC tumor cells and significantly inhibited the proportion of cell apoptosis after Anlotinib treatment. Further research found that USP18, as a deubiquitinating enzyme that can specifically remove ISG15-like ubiquitin-like proteins from substrate proteins, can improve the kinase stability of Aurora B by removing ISG15-like ubiquitin modification and promote MTC tumor cell proliferation through the activation of PI3K-Akt signaling regulated by Aurora B kinase. Application of Aurora B kinase inhibitor in Anlotinib-resistant MTC cell lines significantly inhibited tumor cell proliferation, and Aurora B kinase inhibitor significantly increased the proportion of cell apoptosis in MTC tumor cells overexpressing USP18. In the subcutaneous xenograft tumor model of MTC in NOD/SCID mice, the growth of xenograft tumors in the Anlotinib combined with Aurora B kinase inhibitor treatment group was also significantly inhibited. In summary, overexpressed USP18 can activate PI3K-Akt signaling and promote tumor cell proliferation by increasing the stability of Aurora B kinase, ultimately leading to the formation of Anlotinib resistance in MTC patients. Combined use of Aurora B kinase inhibitor is a potentially effective combined treatment strategy for Anlotinib-resistant MTC patients. Citation Format: Xuan Qin, Xing Wan, Dapeng Li, Yimeng Liu, Xianhui Ruan, Fangkun Luan, Kejia Xu, Jia Li, Rong Xiang, Yongjun Piao, Yi Shi, Xiangqian Zheng. USP18 promotes anlotinib resistance in medullary thyroid carcinoma by stabilizing aurora B kinase [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4665.

Abstract 5569: Mechano-chemical control of secretory cues regulating immune tolerance, survival and invasion in oral squamous cell carcinomas

Abstract Tissue fibrosis and extracellular matrix (ECM) stiffening have been shown to promote tumor cell proliferation, metastasis, and chemoresistance in a range of cancers. Stiffness of the ECM can lead to changes in cancer cell behavior, including enhanced proliferation, activation of mechano-sensitive signaling pathways, and potential genomic damage, with implications for cancer progression and immune responses. Recent research suggests stiff matrix may also induce the release of tumor-derived small extracellular vesicles (sEVs) that promote tumor growth. Tumor-derived sEVs carry bioactive cargo, such as micro-RNAs (miRNAs) and DNA fragments, and function as a unique form of intracellular communication promoting cell survival, growth, and metastasis. Understanding these mechano-sensing mechanisms is essential for identifying potential targets in precision medicine for solid tumor treatment. However, the influence of tumor stiffness on secretory cues, and their subsequent role in immunomodulation and/or chemo-resistance has not been extensively studied. This project aims to explore how tumor stiffness can alter cell responses to genotoxic stress and how these responses can perpetuate feedback to the immune system through the release of secretory cues such as sEVs. Here, we outline the isolation and characterization of tumor-derived sEVs obtained from culture media of oral squamous cell carcinoma (OSCC) spheroids, cultured at varying stiffness (0.2kPa-1.5kPa). In this project, we use OSCC lines that are either sensitive or resistant to cisplatin (HSC-3 and HN-5, respectively). To explore the immunomodulatory effects of these tumor-derived sEVs, we first established a consistent supply of CD206+ve macrophages differentiated from human induced pluripotent stem cells (iMacs), following the established protocol of Douthwaite et al (2021). iMacs were then treated with sEVs with their resulting immunophenotype, and activation assessed. These preliminary experiments provide a step towards understanding how the biophysical environment influences tumor cell resistance to therapy and how sEVs can modulate the relationship between cancer cells and macrophages. Citation Format: Bethany R. Bareham, Matthew Dibble, Leila Mouhib, Aitor Bermejo Arteagabeitia, Subhankar Mukhopadhyay, Maddy Parsons. Mechano-chemical control of secretory cues regulating immune tolerance, survival and invasion in oral squamous cell carcinomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5569.

Abstract 3484: Mechanism of BRAF V600E resistance revealed by cell panel screening and bioinformatics

Abstract The BRAF V600E mutation is pivotal target in the treatment of melanoma. Dabrafenib, one of the most potent inhibitors approved by the FDA, exhibits differential sensitivity across different cancer types. To explore the underlying mechanisms responsible for the resistance of certain cancers to Dabrafenib, we tested a panel of 20 BRAF V600E positive cancer cell lines. Our results showed that 15 of these cell lines demonstrated sensitivity to Dabrafenib, whereas the remaining 5 exhibited resistance. We then investigated the correlation between Dabrafenib potency and gene expression patterns based on public high throughput sequencing data via bioinformatics methods. The results uncovered that the cell lines resistant to Dabrafenib showed low expression of MAP3K1, alongside with elevated expression of G0S2 and PIK3CG. These alterations are known to promote tumor cell proliferation, migration, and invasion, thereby contributing to a reduced sensitivity to BRAF inhibitors. Subsequent in vitro experiments validated the findings derived from our analysis. This unbiased, bioinformatics-driven approach provides valuable insight into the reasons behind treatment resistance and aids in the development of next-generation treatment approaches for inhibitor-resistant cancers. Citation Format: Kaiqiang Hu, Qiuyuan Yang, Pengwei Pan, Fang He. Mechanism of BRAF V600E resistance revealed by cell panel screening and bioinformatics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3484.

Abstract 773: Overexpression of phosphoserine phosphatase (PSPH) in prostate cancer and in tumor microenvironment promotes tumor cell proliferation

Abstract Reprogrammed cellular metabolism is one of the key features of cancer and tumor microenvironment. L-3-phosphoserine phosphatase (PSPH) is one of the five rate-limiting enzymes in the biosynthesis of serine from glucose that supports cell proliferation. Here, we aim to study the role of PSPH in prostate cancer (PCa) and its tumor microenvironment. We find that PSPH not only is overexpressed in prostate cancer cell lines compared to normal prostate epithelial cells (PrEC) and benign prostate epithelial cells (BPH-1), but also exhibits a higher level in patient-derived carcinoma-associated fibroblasts (CAFs) compared to the matched benign associated fibroblasts (BAFs), which are derived from fresh radical prostatectomy specimens of African American (AA) and European American (EA) men. Notably, MDAPCa2b cells derived from an AA prostate cancer patient and AA CAFs have even higher expression of PSPH protein. The mRNA levels of PSPH are also significantly elevated in prostate cancer tissues in AA men compared to EA men and predict poor survival in PCa patients. Knock-down of PSPH expression significantly inhibits the proliferation and colony formation of prostate cancer cells. Growth of xenograft tumors derived from PSPH knockdown MDAPCa2b cells has also been suppressed markedly. Gene expression profiling revealed that suppression of PSPH expression by shRNAs in LNCaP and MDAPCa2b cells is associated with the regulation of gene expression related to metabolism, immunity, extracellular matrix remodeling, and Ion channels. Similarly, analysis of publicly available PCa RNA seq databases also demonstrates that PSPH amplification or over-expression is associated with alterations of gene expression related to metabolism and immunity. Our results suggest that PSPH is upregulated in prostate cancer cells and their surrounding fibroblasts to support tumor growth via reprogramming metabolic pathways and transcriptomes. Citation Format: Liankun Song, Noriko Yokoyama, Jun Xie, Yunjie Hu, Zhenyu (Arthur) Jia, Beverly Wang, Dan Mercola, Edward Uchio, Thomas Ahlering, Michael Lilly, Xiaolin Zi. Overexpression of phosphoserine phosphatase (PSPH) in prostate cancer and in tumor microenvironment promotes tumor cell proliferation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 773.