Regulate Tumor Cell Research Articles

Abstract 2706: Therapeutic silencing of Rictor using siRNA nanoparticles to selectively block mTORC2 signaling in triple negative breast cancer

Abstract Triple negative breast cancers (TNBCs) are aggressive malignancies with a high rate of recurrence even after neoadjuvant chemotherapy (NAC) and resection. Nearly 50% of NAC-treated TNBC patients harboring residual disease display mutations in the phosphatidyl inositol-3 kinase/mechanistic target of rapamycin (PI3K/mTOR) pathway, correlating PI3K/mTOR with chemoresistance. The protein kinase mTOR functions within two distinct protein complexes—mTORC1 and mTORC2. Inhibition of mTORC1 is ineffective in TNBCs. However, less is known regarding mTORC2 as a TNBC drug target, though mTORC2 is known to regulate tumor cell survival and motility/metastasis in other cancers. Here, we leverage siRNA technology to block expression of the mTORC2 obligate cofactor, Rictor, to test the hypothesis that selective mTORC2 inhibition will improve TNBC response to chemotherapy. siRNA-carrying nanoparticle complexes (si-NPs) continue to face systemic siRNA delivery challenges such as limited stability, off-target toxicities, and suboptimal tumor accumulation. Most conventional si-NPs are designed as “binary” systems comprising the siRNA cargo and the polymeric carrier that encapsulates it. Ternary si-NPs containing siRNA, an NP core-forming polymer (50B), and an NP surface-forming polymer (20kPEG-50B) have the potential to improve tumor silencing activity because of the participation of both polymers in siRNA encapsulation and endosome disruptive activity. Through concomitant structure-function optimization of 50B core polymer ratio (50B:20kPEG-50B) and molecular weight, we identified multiple lead ternary si-NPs with potent gene silencing activity, enhanced siRNA loading stability, and minimal toxicity. Following intravenous (i.v) treatment in vivo, all lead ternary si-NPs displayed increased circulation half-life, tumor uptake, and tumor gene silencing relative to the more canonical binary si-NPs. Critically, a single 1 mg/kg i.v. injection of our optimized formulation, 50B8-DP100 si-NPs, resulted in 80% tumor Rictor knockdown in orthotopic MDA-MB-231 tumors in mice. Therapeutic efficacy of 50B8-DP100 si-NPs, harboring siRNA against Rictor (siRictor-NPs) was then tested in models of TNBC. siRictor-NPs decreased cell growth and enhanced apoptosis in multiple TNBC cell lines. In an orthotopic HCC70 TNBC model, i.v. treatment with siRictor-NPs revealed substantial inhibition of mTORC2 activity in tumors by western analysis. siRictor-NP treatment also inhibited tumor growth to 52% relative to siControl-NP treatment. Preliminary in vitro studies further indicate that combining chemotherapy with siRictor-NPs improves TNBC cell killing over chemotherapy alone. Together, this work provides strong evidence for the therapeutic potential of Rictor knockdown and identifies a novel nanotechnology for the treatment of PI3K-active TNBC. Citation Format: Shrusti S. Patel, Ella N. Hoogenboezem, Fang Yu, Alex G. Sorets, Fiona K. Cherry, Justin H. Lo, Nora Francini, Richard A. d'Arcy, Rebecca S. Cook, Craig L. Duvall. Therapeutic silencing of Rictor using siRNA nanoparticles to selectively block mTORC2 signaling in triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2706.

Abstract 3941: Enzymatic nitration in oncology

Abstract Background: We have discovered a new class of enzymes, that we name the nitrases, that catalyze the post-translation nitration of specific tyrosine residues of key proteins, several of which regulate important oncogenic pathways and are negatively prognostic in multiple cancer types. Materials And Methods: To identify protein substrates for 31 candidate nitrases, we incubated each nitrase with a 23,000 protein chip in a nitrase assay containing peroxynitrite and using anti-nitrotyrosine antibodies to detect the proteins that were nitrated. We then confirmed this nitration in separate biochemical assays and determined the specific site of nitration by LC-MS. Further, nitrases were evaluated in silico against TCGA gene expression and GISTIC copy number databases for specific cancer associations. Results: We have discovered that several proteins known to regulate tumor cell survival and/or evasion of immune surveillance are specifically nitrated by different nitrases and that their biochemical activities are regulated by this nitration. Pak4, a protein that has been implicated as an oncogenic driver, as well as in immune evasion is specifically nitrated by Nitrase #3 and increases its kinase activity. Interestingly, Nitrase #3 also nitrates Pak5, but not any of the other Pak family members, demonstrating high enzymatic specificity. Targeted inhibition or degradation of nitrated Pak4 or inhibition of Nitrase #3 may have therapeutic potential in oncology. Similarly, RhoA, a protein implicated in the oncogenic state of tumors is nitrated by Nitrase #12. This nitration activates RhoA biochemically and in cells. Bax is a specific substrate for Nitrase #11. Nitration of Bax reduces the cytochrome C release from the mitochondria induced by Bax. For each of these enzymes, we will develop specific inhibitors to determine their therapeutic potential in tumorigenesis. We further performed in silico analysis of nitrases for overall survival association in 17 cancer types. Utilizing TCGA RNA expression data and The Human Protein Atlas, nitrases were screened for association with overall survival in relation to nitrase RNA expression. Nitrases showing higher overall survival with low nitrase RNA expression and p. value <0.001 were identified as negatively prognostic. 10 nitrases showed negative prognostic association, suggesting that they could be favorable therapeutic targets. Three nitrases, N11, N12, N18, were negatively prognostic in renal clear cell carcinoma and nitrases N1 and N13 were negatively prognostic in liver cancer. Conclusions: A new class of enzymes we discovered offers multiple opportunities for development of effective chemotherapeutic agents against a variety of oncogenic targets and in specific cancers that show negative association of high nitrase expression. Citation Format: Arun Kashyap, Sami Hussein, Sahar Mazar, Kate Markham, Anthony Mastracci, Ritu Sharma, Sheerin K. Shahidi-Latham, Irene Griswold-Prenner. Enzymatic nitration in oncology. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3941.

Abstract 273: Synergistically suppressive effects by combination of glycolytic inhibitor with TRAP1-depletion in colorectal cancer

Abstract Tumor necrosis factor receptor-associated protein 1 (TRAP1) is a mitochondrial homolog of HSP90 chaperones. It plays an important role in protection against oxidative stress and apoptosis by regulating reactive oxidative species (ROS). Recent studies have suggested TRAP1 as a regulator of metabolism and mitochondrial homeostasis in diverse pathological states, including cancer. To further elucidate the mechanistic role of TRAP1 in regulating tumor cell survival, we used gamitrinib-triphenylphosphonium (G-TPP) to inhibit TRAP1 signaling pathways in colon cancer. Inhibition of TRAP1 disrupted redox homeostasis and increased ER stress in colon cancer. To confirm the G-TPP effects of TRAP1 inhibition in colon cancer, we performed TRAP1 CRISPR/Cas9 to deplete TRAP1 expression in colon cancer cell line CT26. TRAP1-depleted cells were found to acquire several distinct phenotypes: induction of reactive oxidative species (ROS) level, reduction of cell growth, and lower pH value of culture medium. In addition, proteomic data showed that depletion of TRAP1 induced significant metabolism alteration in CT26 cells. Using seahorse assay to access mitochondrial respiration and glycolysis, we found that TRAP1-depleted cells were insensitive to Oxidative Phosphorylation (OXPHOS) inhibitor treatment and significantly increased extracellular acidification rate (ECAR) compared to parental cells. Furthermore, higher glucose consumption rate and higher lactic acid level of culture medium were observed in TRAP1-depleted cells. On the other hand, Glycolytic inhibitor (2DG) led to excessive ROS production, reduction of glucose uptake and exacerbated cell death in TRAP1-depleted cell compared to parental cells. Taken together, depletion of TRAP1 induces mitochondrial dysfunction and modulates metabolic switch toward aerobic glycolysis in TRAP1-depleted colon cancer cells. Dual inhibition of TRAP1 and glycolytic signaling may increase therapeutic efficiency through induction of excessive ROS production in colon cancer. Citation Format: Hong-Yuan Tsai, Miao-Hsueh Chen, Herath Lakmini Senavirathna, Jihye Yun, Sheng Pan, Ru Chen. Synergistically suppressive effects by combination of glycolytic inhibitor with TRAP1-depletion in colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 273.

Matrix stiffness regulates tumor cell intravasation through expression and ESRP1-mediated alternative splicing of MENA

During intravasation, cancer cells cross the endothelial barrier and enter the circulation. Extracellular matrix stiffening has been correlated with tumor metastatic potential; however, little is known about the effects of matrix stiffness on intravasation. Here, we utilize invitro systems, a mouse model, specimens from patients with breast cancer, and RNA expression profiles from The Cancer Genome Atlas Program (TCGA) to investigate the molecular mechanism by which matrix stiffening promotes tumor cell intravasation. Our data show that heightened matrix stiffness increases MENA expression, which promotes contractility and intravasation through focal adhesion kinase activity. Further, matrix stiffening decreases epithelial splicing regulatory protein 1 (ESRP1) expression, which triggers alternative splicing of MENA, decreases the expression of MENA11a, and enhances contractility and intravasation. Altogether, our data indicate that matrix stiffness regulates tumor cell intravasation through enhanced expression and ESRP1-mediated alternative splicing of MENA, providing a mechanism by which matrix stiffness regulates tumor cell intravasation.

SIRT7 orchestrates melanoma progression by simultaneously promoting cell survival and immune evasion via UPR activation

Melanoma is the most lethal type of skin cancer, originating from the malignant transformation of melanocyte. While the development of targeted therapy and immunotherapy has gained revolutionary advances in potentiating the therapeutic effect, the prognosis of patients with melanoma is still suboptimal. During tumor progression, melanoma frequently encounters stress from both endogenous and exogenous sources in tumor microenvironment. SIRT7 is a nuclear-localized deacetylase of which the activity is highly dependent on intracellular nicotinamide adenine dinucleotide (NAD+), with versatile biological functions in maintaining cell homeostasis. Nevertheless, whether SIRT7 regulates tumor cell biology and tumor immunology in melanoma under stressful tumor microenvironment remains elusive. Herein, we reported that SIRT7 orchestrates melanoma progression by simultaneously promoting tumor cell survival and immune evasion via the activation of unfolded protein response. We first identified that SIRT7 expression was the most significantly increased one in sirtuins family upon stress. Then, we proved that the deficiency of SIRT7 potentiated tumor cell death under stress in vitro and suppressed melanoma growth in vivo. Mechanistically, SIRT7 selectively activated the IRE1α-XBP1 axis to potentiate the pro-survival ERK signal pathway and the secretion of tumor-promoting cytokines. SIRT7 directly de-acetylated SMAD4 to antagonize the TGF-β-SMAD4 signal, which relieved the transcriptional repression on IRE1α and induced the activation of the IRE1α-XBP1 axis. Moreover, SIRT7 up-regulation eradicated anti-tumor immunity by promoting PD-L1 expression via the IRE1α-XBP1 axis. Additionally, the synergized therapeutic effect of SIRT7 suppression and anti-PD-1 immune checkpoint blockade was also investigated. Taken together, SIRT7 can be employed as a promising target to restrain tumor growth and increase the effect of melanoma immunotherapy.

Tenascin-C affects invasiveness of EGFR-mutated lung adenocarcinoma through a putative paracrine loop

Tenascin C (TNC) is an extracellular matrix (ECM) protein and a potential biomarker affecting progression of different tumor types, such as pancreatic and lung cancer. Alternative splicing variants of TNC are known to have an impact on interaction partners like other ECM proteins or cell surface receptors, including epidermal growth factor receptor (EGFR), leading to numerous and sometimes opposite roles of TNC in tumor cell dissemination and proliferation. Only little is known about the impact of TNC on biologic characteristics of lung cancer, such as invasion and metastatic potential. In the present study, we could link an increased expression of TNC in lung adenocarcinoma (LUAD) tissues with an unfavorable clinical outcome of patients. Furthermore, we investigated the functional role of TNC in LUAD. Immunohistochemical staining of TNC revealed a significant increase of TNC levels in primary tumours and metastases compared to normal lung tissue. Additionally, a significant correlation between TNC mRNA expression and EGFR copy number and protein expression levels has been determined. Moreover, inhibition of TNC in lung fibroblasts led to reduced invasiveness of LUAD cells harboring EGFR-activating mutations and to a shorter lamellipodia perimeter and a reduced lamellipodia area on the surface of LUAD cells. This study provides the evidence that TNC expression might be a biological relevant factor in LUAD progression in an EGFR-dependent manner and that it regulates tumor cell invasion by rearrangement of the actin cytoskeleton, especially affecting lamellipodia formation.

Fatty acids in cancer: Metabolic functions and potential treatment

AbstractLipid metabolic reprogramming is one of the important metabolic characteristics of cancer cells. As major components of lipids, fatty acids provide energy and material basis for cancer cell survival. Abnormal fatty acid metabolism has been found in many cancers. Fatty acid uptake, transport, and synthesis are closely related to the pathogenesis of cancer. Meanwhile, fatty acid changes in the membrane structure of cancer cells and signal transduction mediated by signaling lipids are also helping cancer cells survive in the changing microenvironment. Some of these enzymes and metabolites involved in fatty acid metabolism are emerging as unique cancer biomarkers. Multiple studies have shown that disordered fatty acids can regulate tumor cell proliferation, metastasis, and drug resistance. Therefore, targeting fatty acid metabolism has become a promising treatment strategy. Here, we mainly present metabolic alterations of fatty acids, the basic components of lipids, in cancer. We discuss the cancer treatment based on fatty acid and fatty acid metabolism. These may provide a basis for a better understanding of lipid metabolic reprogramming in cancer, and also provide new ideas for cancer biomarker search, drug development, and combination therapy.

Abstract P6-14-09: Non-canonical Wnt/Ror2 signaling regulates tumor cell invasion and dissemination in breast cancer through cell-matrix crosstalk

Abstract BACKGROUND: Metastasis is the main cause of mortality for breast cancer patients. The early steps of cancer metastasis require that tumor cells actively invade and disseminate from the primary tumor to distant organs. Cell-extracellular matrix (ECM) interactions represent fundamental interactions during tumor invasion and metastasis, yet how particular signal-transduction factors prompt the conversion of tumor cells into migratory populations capable of systemic dissemination remains elusive. OBJECTIVES: Wnt signaling is a known regulator of cell fate, migration, and polarity during various key biological processes. We previously discovered an inverse correlation between the canonical Wnt signature and a non-canonical Wnt receptor, Ror2, across breast cancers in TCGA. The objective of this study is to investigate how canonical and non-canonical Wnt signaling orchestrate tumor cell behavior during cancer invasion and metastasis. METHODS: We used clinically relevant syngeneic TP53-null Genetically Engineered Mouse Model (GEMM) tumors that molecularly reflect the different breast cancer intrinsic subtypes. In vivo transplantation of GEMM models and in vitro 3D tumor organoids were employed to elucidate the molecular mechanism underlying the migration, invasion, and metastasis of tumor cells upon genetic perturbation of Wnt/Ror2 signaling. RESULTS/DISCUSSION: From 3-dimensional (3D) tumor organoid models, we identified novel transcriptional alterations encompassing cell-cell adhesion, cytoskeletal remodeling, and ECM organization upon Ror2 loss. At protein levels, we discovered a significant increase in collagen fibril organization and integrin-α5 and integrin-β3 expression following Ror2 depletion. In addition, the matrisomal protein fibronectin (FN) was concomitantly upregulated and assembled in Ror2-deficient tumor cells at sites of invasion. Consequently, we observed FAK activation and actin cytoskeleton alterations in Ror2-deficient tumor cells, leading to a promigratory tumor cell behavior. The altered cytoskeleton and cell-ECM interaction enhanced the rigidity of the Ror2-depleted cells. Furthermore, Inhibition of either integrin or FAK activation abrogated the increased invasion driven by Ror2-loss. Unexpectedly, these changes were distinct from processes regulated by Wnt/ß-catenin activation. From both spontaneous metastasis and experimental metastasis models, we discovered a shift from canonical to non-canonical Wnt signaling throughout the progression of lung metastasis, indicating that the balance of Wnt signaling may serve as a switch to dictate cell functions at different stages of metastatic development. Consistently, we found enhanced initial colonization in the lungs when Ror2 is depleted in these breast cancer cells. Together, these studies provide new insight into how canonical and alternative Wnt pathways coordinate cell-cell and cell-ECM exchanges during breast cancer progression and metastasis. Supported by grant NIH-CA016303 Citation Format: Hongjiang Si, Na Zhao, Andrea Pedroza, Chad Creighton, Jeffrey Rosen, Kevin Roarty. Non-canonical Wnt/Ror2 signaling regulates tumor cell invasion and dissemination in breast cancer through cell-matrix crosstalk [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-14-09.

Circ_0031242 regulates the functional properties of hepatocellular carcinoma cells through the miR-944/MAD2L1 axis.

Circular RNAs (circRNAs) possess key functions in the pathogenesis of hepatocellular carcinoma (HCC). Nonetheless, the actions of individual circRNAs in HCC remain undefined. circ_0031242, miR-944, and MAD2L1 expression were quantified by qRT-PCR. Transwell assay was utilized to examine cell invasion and migration. Glucose consumption and lactate production were measured to assess the impact on glycolysis. The relationships among circ_0031242, MAD2L1, and miR-944 were examined via luciferase reporter assay. circ_0031242 was notably augmented in HCC. Loss of function of circ_0031242 hindered cell proliferation, invasion, migration, glycolysis, and promoted apoptosis, as well as impeding HCC tumor growth. circ_0031242 directly targeted miR-944. Inhibition of miR-944 counteracted the effects of si-circ_0031242 on HCC cells. Additionally, miR-944 was proved to directly target MAD2L1 in HCC cells. Moreover, the promotion of MAD2L1 was able to rescue the inhibition of high miR-944 expression on HCC cell progression. Meanwhile, circ_0031242 involved the post-transcriptional modulation of MAD2L1 through miR-944. This study suggested that circ_0031242 regulated tumor cell progression and tumor growth through the miR-944/MAD2L1 axis in HCC.

Exosomal circular RNAs: A chief culprit in cancer chemotherapy resistance.

Chemotherapy is one of the primary treatments for malignant tumors. However, the acquired drug resistance hinders clinical efficacy and leads to treatment failure in most patients. Exosomes are cell-derived vesicles with a diameter of 30-150nm carrying and delivering substances such as DNAs, RNAs, lipids, and proteins for cellular communication in tumor development. Circular RNAs (circRNAs) present covalently closed-loop RNA structures, which regulate tumor cell proliferation, apoptosis, and metastasis by controlling different genes and signaling pathways. CircRNAs are abundant and stably expressed in exosomes. Recent studies have shown that they play critical roles in chemotherapy resistance in various cancers. In this review, we summarized the origin of exosomes and discussed the regulation mechanism of exosomal circRNAs in cancer drug resistance.

Transcriptional Reprogramming Regulates Tumor Cell Survival in Response to Ionizing Radiation: a Role of p53.

Senexin B, a non-toxic selective inhibitor of cyclin-dependent protein kinases 8 and 19 (CDK8 and CDK19), in combination with γ-photon irradiation in doses of 2-10 Gy increased the death of colon adenocarcinoma cell line HCT116 (intact p53) in a logarithmically growing culture, which was accompanied by the prevention of cell cycle arrest and a decrease of "senescence" phenotype. The effect of senexin B in cells with intact p53 is similar to that of Tp53 gene knockout: irradiated HCT116p53KO cells passed through the interphase and died independently of senexin B. The inhibitor reduced the ability of cells to colony formation in response to irradiation; p53 status did not affect the effectiveness of the combination of radiation and senexin B. Thus, the CDK8/19 inhibitor senexin B increased cell sensitivity to radiotherapy by mechanisms dependent and independent of p53 status.

P2X7 receptor promotes migration and invasion of non-small cell lung cancer A549 cells through the PI3K/Akt pathways.

It has been demonstrated that the ATP-gated ion channel P2X7 receptor is involved in tumor progression and plays an important role in regulating tumor cell growth, invasion, migration and angiogenesis. However, P2X7 receptors have been relatively poorly studied in non-small cell lung cancer (NSCLC) cells. Therefore, the aim of this study was to investigate the effects of P2X7 receptor on A549 cells (NSCLC cell line) migration and invasion and to reveal the molecular mechanisms mediated by it. We detected the expression and function of P2X7 receptor in A549 cells. The effects and mechanisms of P2X7 receptor on A549 cells migration, invasion, and epithelial-mesenchymal transition were detected in vitro and in vivo. The results showed P2X7 receptor expressed by A549 cells had ion channel and macropore formation function. In addition, activation of P2X7 receptor by adenosine triphosphate (ATP) or 2'(3')-O-(4-Benzoylbenzoyl)-adenosine-5'-triphosphate (BzATP) promoted Epithelial-mesenchymal transition (EMT), migration and invasion of A549 cells, which was attenuated by treatment of cells with P2X7 receptor antagonist A438079 and Oxidized ATP. Furthermore, activation of P2X7 receptor increased phosphorylated protein kinase B (p-Akt) levels, and the phosphatidylinositol-tris-phosphate kinase 3 (PI3K)/protein kinase B (Akt) inhibitor LY294002 blocked migration and invasion of A549 cells induced by ATP or BzATP. At the same time, in vivo results showed that P2X7 receptor could also promote EMT and PI3K/Akt expression in transplanted tumors. Our study indicated that P2X7 receptor promotes A549 cells migration and invasion through the PI3K/Akt signaling pathway, suggesting that P2X7 receptor may be a potential therapeutic target for NSCLC.

TIM-4 orchestrates mitochondrial homeostasis to promote lung cancer progression via ANXA2/PI3K/AKT/OPA1 axis

Mitochondrial function and homeostasis are critical to the proliferation of lung cancer cells. T-cell immunoglobulin and mucin domain-containing molecule 4 (TIM-4) promotes the development and progression of lung cancer. However, the role of TIM-4 in mitochondria homeostasis in tumor cells remains completely unknown. In this study, we found that TIM-4 promoted growth and proliferation of lung cancer cells by the oxidative phosphorylation (OXPHOS) pathway. Consistently, inhibition of OXPHOS reversed TIM-4-induced proliferation of lung cancer cells. Notably, TIM-4 promoted mitochondrial fusion via enhancing L-OPA1 protein expression. Mechanistically, TIM-4 regulated protein of L-OPA1 through the PI3K/AKT pathway, and TIM-4 interacted with ANXA2 to promote the activation of PI3K/AKT signaling. Collectively, TIM-4 promotes oxidative phosphorylation of lung cancer cells to accelerate tumor progress via ANXA2/PI3K/AKT/OPA1 axis, which sheds significant new lights on the potential role of TIM-4 in regulating tumor cell metabolism.

CircANKRD28 inhibits cisplatin resistance in non-small-cell lung cancer through the miR-221-3p/SOCS3 axis.

Non-small-cell lung cancer (NSCLC) is a common cancer. Chemotherapeutic drug resistance limits the therapeutic effect of NSCLC and leads to a poor prognosis. As a result, new specific targets may be better identified by studying the mechanism of drug resistance to cisplatin in NSCLC. In the present study, we performed a quantitative real-time polymerase chain reaction and western blotting to detect mRNA and protein levels. The proliferation of cells was analyzed by a Cell Counting Kit-8 and colony formation assays. Cell invasion was measured via the Transwell assay. A scratch assay was performed to measure cell migration in cisplatin (DDP)-resistant NSCLC cells. Apoptosis of cells was examined using flow cytometry. We found that circANKRD28 was notably decreased in NSCLC. The results showed that circANKRD28 expression was not affected, and its half-life was more than 12 h. Functional experiments revealed that circANKRD28 overexpression inhibited DDP resistance in NSCLC cells in vitro. Mechanistic findings demonstrated that circANKRD28 regulated tumor cell progression and DDP sensitivity through the miR-221-3p/SOCS3 axis. The present study revealed the regulatory effects and molecular mechanism of circANKRD28 on the development and cisplatin resistance in NSCLC, which may provide experimental basis and theoretical support to identify new targets for therapy of DDP resistance in NSCLC.

Exploring the role of sphingolipid-related genes in clinical outcomes of breast cancer.

Despite tremendous advances in cancer research, breast cancer (BC) remains a major health concern and is the most common cancer affecting women worldwide. Breast cancer is a highly heterogeneous cancer with potentially aggressive and complex biology, and precision treatment for specific subtypes may improve survival in breast cancer patients. Sphingolipids are important components of lipids that play a key role in the growth and death of tumor cells and are increasingly the subject of new anti-cancer therapies. Key enzymes and intermediates of sphingolipid metabolism (SM) play an important role in regulating tumor cells and further influencing clinical prognosis. We downloaded BC data from the TCGA database and GEO database, on which we performed in depth single-cell sequencing analysis (scRNA-seq), weighted co-expression network analysis, and transcriptome differential expression analysis. Then seven sphingolipid-related genes (SRGs) were identified using Cox regression, least absolute shrinkage, and selection operator (Lasso) regression analysis to construct a prognostic model for BC patients. Finally, the expression and function of the key gene PGK1 in the model were verified by in vitro experiments. This prognostic model allows for the classification of BC patients into high-risk and low-risk groups, with a statistically significant difference in survival time between the two groups. The model is also able to show high prediction accuracy in both internal and external validation sets. After further analysis of the immune microenvironment and immunotherapy, it was found that this risk grouping could be used as a guide for the immunotherapy of BC. The proliferation, migration, and invasive ability of MDA-MB-231 and MCF-7 cell lines were dramatically reduced after knocking down the key gene PGK1 in the model through cellular experiments. This study suggests that prognostic features based on genes related to SM are associated with clinical outcomes, tumor progression, and immune alterations in BC patients. Our findings may provide insights for the development of new strategies for early intervention and prognostic prediction in BC.

SOX2 Promotes Radioresistance in Non-small Cell Lung Cancer by Regulating Tumor Cells Dedifferentiation.

Background: Radiation therapy plays an important role in the treatment of patients with non-small cell lung cancer (NSCLC). However, the radiocurability is greatly limited because of radioresistance which leads to treatment failure, tumor recurrence, and metastasis. Cancer stem cell (CSC) has been identified as the main factor that contributes to radiation resistance. SOX2, one of the transcription factors specifically expressed in CSC, is involved in tumorigenesis, progression, and maintenance of cell stemness. But the association between SOX2 and NSCLC radioresistance is not clear now. Methods: We constructed the radiotherapy-resistant cell line of NSCLC by multiple radiotherapy treatments. Colony formation assay, western blot, and immunofluorescence were performed to detect the radiosensitivity of cells. Western blot, qRT-PCR, and sphere formation assay were used to detect CSC characteristics of cells. Wound healing assay and Transwell assay were used to determine cell migration motility. The SOX2-upregulated model and SOX2-downregulated model was constructed by lentivirus transduction. Finally, the expression and clinical relevance of SOX2 in NSCLC were investigated by bioinformatics analysis based on TCGA and GEO datasets. Results: The expression of SOX2 was increased in radioresistant cells and a trend of dedifferentiation were observed. The results of wound healing assay and Transwell assay showed that SOX2 overexpression significantly promote the migration and invasion of NSCLC cells. Mechanistically, overexpression of SOX2 enhanced radioresistance and DNA damage repair capability of parental cells, while down-regulation of SOX2 led to decreased radioresistance and DNA repair ability in radioresistant cells, all of which were related to cells dedifferentiation regulated by SOX2. In addition, bioinformatics analysis show that high expression of SOX2 was strongly associated with the progression and poor prognosis of patients with NSCLC. Conclusions: Our study revealed that SOX2 regulates radiotherapy resistance in NSCLC via promoting cell dedifferentiation. Therefore, SOX2 may be a promising therapeutic target for overcoming radioresistance in NSCLC, providing a new perspective to improve the curative effect.

Autophagy Inhibition Contributes to Apoptosis of PLK4 Downregulation-induced Dormant Cells in Colorectal Cancer.

Dormant cancer cells account for cancer recurrence, distant metastasis and drug resistance which lead to poor prognosis in colorectal cancer (CRC). However, little is known about the molecular mechanisms regulating tumor cell dormancy and how to eliminate dormant cancer cells. Recent studies indicate autophagy affects dormant tumor cell survival. Here, we found that polo-like kinases 4 (PLK4), a central regulator of the cell cycle and proliferation, plays a crucial role in regulating CRC cells dormancy both in vitro and in vivo. Downregulation of PLK4 induced dormancy and inhibited migration and invasion in different CRC cell lines. Clinically, PLK4 expression was correlated with the dormancy markers (Ki67, p-ERK, p-p38) and late recurrence in CRC tissues. Mechanistically, downregulation of PLK4 induced autophagy contributed to restoring phenotypically aggressive tumor cells to a dormant state through the MAPK signaling pathway, and inhibition of autophagy would trigger apoptosis of dormant cells. Our findings reveal that downregulation of PLK4-induced autophagy contributes to tumor dormancy and autophagy inhibition leads to apoptosis of CRC dormant cells. Our study is the first to report that downregulation PLK4 induced autophagy is an early event in CRC dormancy and highlights autophagy inhibitor as a potential therapeutic target for dormant cell elimination.

S100A10 Overexpression Correlates with Adverse Prognosis, Tumor Microenvironment, and Aggressive Behavior In Vitro and In Vivo of Cervical Cancer.

Background: The incidence of cervical squamous cell carcinoma and endocervical adenocarcinoma (CESC) is increasing in women. S100A10 overexpression is commonly reported in various malignancies and is closely associated with tumor cell characteristics and prognosis. Methods: The expression of S100A10 and its prognostic relevance were assessed utilizing RNA-seq data from The Cancer Genome Atlas. S100A10 regulation of CESC cell growth and migration was investigated using CCK-8, colony-forming, and Transwell-based approaches. Xenograft model mice were used to examine the in vivo effects of S100A10, and differentially expressed genes (DEGs) linked to S100A10 were identified to explore its functional role in oncogenesis. Associations between S100A10 levels, chemosensitivity, and the immune microenvironment were assessed, and the mutational and methylation status of S100A10 was evaluated using the cBioPortal and MethSurv databases, respectively. Results: S100A10 was upregulated in CESC samples, and higher S100A10 mRNA levels were associated in poor prognostic outcomes. The area under the curve for S100A10 when diagnosing CESC was 0.935, and S100A10 was found to regulate tumor cell proliferation and metastasis both in vitro and in vivo. Overall, 1125 DEGs enriched in crucial CESC progression-associated signaling pathways were identified. S100A10 expression was also associated with the intratumoral immune microenvironment and immune checkpoint activity. Patients expressing elevated S100A10 levels exhibited distinct chemotherapeutic susceptibility, and methylation of the S100A10 gene was correlated with patient survival outcomes. Conclusion: In summary, this research demonstrated that S100A10 plays a crucial role in regulating CESC development, prognosis, and the intratumoral immune microenvironment. Thus, S100A10 shows potential as a prognostic or diagnostic tool and as a potential target for CESC immunotherapy.

Chemical characterization and antineoplastic effect of oligosaccharides from Cabernet Franc red wine in mammary tumor model in mice

The present study characterized oligosaccharide compounds (Oligo) in Cabernet Franc red wine and investigated its antineoplastic effects against mammary tumor cells in vivo and in vitro, isolated or in combination with chemotherapy. The Oligo fraction was characterized by nuclear magnetic resonance spectroscopy and mass spectrometry. The complex mixture of Oligo showed high amounts of oligoxyloglucuronans, oligorhamnogalacturonans, oligoarabinogalactans, and oligoglucans, such as trehalose and isomaltotriose. To investigate the antineoplastic effects of Oligo, Female Swiss mice were subcutaneously inoculated with Ehrlich tumor cells and then received vehicle (distilled water, p.o.), Oligo solution (9, 35, or 70 mg/kg, p.o.), or methotrexate (1.5 mg/kg, i.p.). The treatments were administered in a conventional (21-d) or chemopreventive (42-d) protocol. Oligo reduced the growth of Ehrlich tumors in both protocols and increased the effectiveness of methotrexate in controlling tumor growth. Oligo did not reduce the viability of MCF-7, MDA-MB-231, MDA-MB-436, and HB4a human breast cells that were cultured for 48 h, showing no cytotoxicity. Overall, Oligo exerted an in vivo antineoplastic effect and modulated immune blood cells, dependent on treatment time, and was not directly cytotoxic to tumor cells. Thus, Oligo may indirectly regulate tumor cell development and may be a promising drug for cancer therapy in combination with methotrexate.

Construction of a ferroptosis-related signature based on seven lncRNAs for prognosis and immune landscape in clear cell renal cell carcinoma

BackgroundRecent studies have demonstrated that long non-coding RNAs (lncRNAs) are involved in regulating tumor cell ferroptosis. However, prognostic signatures based on ferroptosis-related lncRNAs (FRLs) and their relationship to the immune microenvironment have not been comprehensively explored in clear cell renal cell carcinoma (ccRCC).MethodsIn the present study, the expression profiles of ccRCC were acquired from The Cancer Genome Atlas (TCGA) database; 459 patient specimens and 69 adjacent normal tissues were randomly separated into training or validation cohorts at a 7:3 ratio. We identified 7 FRLs that constitute a prognostic signature according to the differential analysis, correlation analysis, univariate regression, and least absolute shrinkage and selection operator (LASSO) Cox analysis. To identify the independence of risk score as a prognostic factor, univariate and multivariate regression analyses were also performed. Furthermore, CIBERSORT was conducted to analyze the immune infiltration of patients in the high-risk and low-risk groups. Subsequently, the differential expression of immune checkpoint and m6A genes was analyzed in the two risk groups.ResultsA 7-FRLs prognostic signature of ccRCC was developed to distinguish patients into high-risk and low-risk groups with significant survival differences. This signature has great prognostic performance, with the area under the curve (AUC) for 1, 3, and 5 years of 0.713, 0.700, 0.726 in the training set and 0.727, 0.667, and 0.736 in the testing set, respectively. Moreover, this signature was significantly associated with immune infiltration. Correlation analysis showed that risk score was positively correlated with regulatory T cells (Tregs), activated CD4 memory T cells, CD8 T cells and follicular helper T cells, whereas it was inversely correlated with monocytes and M2 macrophages. In addition, the expression of fourteen immune checkpoint genes and nine m6A-related genes varied significantly between the two risk groups.ConclusionWe established a novel FRLs-based prognostic signature for patients with ccRCC, containing seven lncRNAs with precise predictive performance. The FRLs prognostic signature may play a significant role in antitumor immunity and provide a promising idea for individualized targeted therapy for patients with ccRCC.