Chemoresistant Cells Research Articles

A Single-Center Retrospective Analysis of Kaposi's Sarcoma: Is There a Relationship Between Emmprin/CD147 Expression and Biological Behavior?

Emmprin (CD147/BSG) protein is estimated to play a key role in cell migration and chemoresistance in viral carcinogenesis. However, there are very limited studies investigating the CD147 in the oncogenesis of Kaposi's sarcoma-associated herpesvirus. This study aims to reveal the relationship between CD147 expression with histopathological parameters, disease pattern, and recurrence in Kaposi's sarcoma (KS). The study included 67 patients diagnosed with KS between January 1982 and September 2023. Clinical and histopathological features were analyzed retrospectively. HHV-8, CD31, and CD147 expressions were evaluated by immunohistochemistry. Sixteen (24%) female and 51 (76%) male patients with median age of 64 (10-86) were included in the study. CD147 was positive in 57 (85%) cases and associated with nodular pattern (P = .001), presence of solid/fibrosarcomatous area (P = .005), and high mitotic activity (P = .035). The disease relapsed in 17 (27%) of the 63 patients with median 2 (0-12) years follow-up. While a 5-year relapse-free survival was 48.5% in the CD147 diffuse positive group, it was 83.4% in focal positive and 100% in negative cases (P = .029). Our study exhibited the relationship between CD147 overexpression and recurrence in KS, but the inhomogeneity of the treatment groups and the small number of patients should also be considered. These findings may provide insight into the pathogenesis of KS and the development of targeted therapies in the future.

Albendazole inhibits colon cancer progression and therapy resistance by targeting ubiquitin ligase RNF20.

The repurposing of FDA-approved drugs for anti-cancer therapies is appealing due to their established safety profiles and pharmacokinetic properties and can be quickly moved into clinical trials. Cancer progression and resistance to conventional chemotherapy remain the key hurdles in improving the clinical management of colon cancer patients and associated mortality. High-throughput screening (HTS) was performed using an annotated library of 1,600 FDA-approved drugs to identify drugs with strong anti-CRC properties. The candidate drug exhibiting most promising inhibitory effects in in-vitro studies was tested for its efficacy using in-vivo models of CRC progression and chemoresistance and patient derived organoids (PTDOs). Albendazole, an anti-helminth drug, demonstrated the strongest inhibitory effects on the tumorigenic potentials of CRC cells, xenograft tumor growth and organoids from mice. Also, albendazole sensitized the chemoresistant CRC cells to 5-fluorouracil (5-FU) and oxaliplatin suggesting potential to treat chemoresistant CRC. Mechanistically, Albendazole treatment modulated the expression of RNF20, to promote apoptosis in CRC cells by delaying the G2/M phase and suppressing anti-apoptotic-Bcl2 family transcription. Albendazole, an FDA approved drug, carries strong therapeutic potential to treat colon cancers which are aggressive and potentially resistant to conventional chemotherapeutic agents. Our findings also lay the groundwork for further clinical testing.

Molecular mechanisms of pancreatic cancer liver metastasis: the role of PAK2.

Pancreatic cancer remains an extremely malignant digestive tract tumor, posing a significant global public health burden. Patients with pancreatic cancer, once metastasis occurs, lose all hope of cure, and prognosis is extremely poor. It is important to investigate liver metastasis of Pancreatic cancer in depth, not just because it is the most common form of metastasis in pancreatic cancer, but also because it is crucial for treatment planning and prognosis assessment. This study aims to delve into the mechanisms of pancreatic cancer liver metastasis, with the goal of providing crucial scientific groundwork for the development of future treatment methods and drugs. We explored the mechanisms of pancreatic cancer liver metastasis using single-cell sequencing data (GSE155698 and GSE154778) and bulk data (GSE71729, GSE19279, TCGA-PAAD). Initially, Seurat package was employed for single-cell data processing to obtain expression matrices for primary pancreatic cancer lesions and liver metastatic lesions. Subsequently, high-dimensional weighted gene co-expression network analysis (hdWGCNA) was used to identify genes associated with liver metastasis. Machine learning algorithms and COX regression models were employed to further screen genes related to patient prognosis. Informed by both biological understanding and the outcomes of algorithms, we meticulously identified the ultimate set of liver metastasis-related gene (LRG). In the study of LRG genes, various databases were utilized to validate their association with pancreatic cancer liver metastasis. In order to analyze the effects of these agents on tumor microenvironment, we conducted an in-depth analysis, including changes in signaling pathways (GSVA), cell differentiation (pseudo-temporal analysis), cell communication networks (cell communication analysis), and downstream transcription factors (transcription factor activity prediction). Additionally, drug sensitivity analysis and metabolic analysis were performed to reveal the effects of LRG on gemcitabine resistance and metabolic pathways. Finally, functional experiments were conducted by silencing the expression of LRG in PANC-1 and Bx-PC-3 cells to validate its influence to proliferation and invasiveness on PANC-1 and Bx-PC-3 cells. Through a series of algorithmic filters, we identified PAK2 as a key gene promoting pancreatic cancer liver metastasis. GSVA analysis elucidated the activation of the TGF-beta signaling pathway by PAK2 to promote the occurrence of liver metastasis. Pseudo-temporal analysis revealed a significant correlation between PAK2 expression and the lower differentiation status of pancreatic cancer cells. Cell communication analysis revealed that overexpression of PAK2 promotes communication between cancer cells and the tumor microenvironment. Transcription factor activity prediction displayed the transcription factor network regulated by PAK2. Drug sensitivity analysis and metabolic analysis revealed the impact of PAK2 on gemcitabine resistance and metabolic pathways. CCK8 experiments showed that silencing PAK2 led to a decrease in the proliferative capacity of pancreatic cancer cells and scratch experiments demonstrated that low expression of PAK2 decreased invasion capability in pancreatic cancer cells. Flow cytometry reveals that PAK2 significantly inhibited apoptosis in pancreatic cancer cell lines. Molecules related to the TGF-beta pathway decreased with the inhibition of PAK2, and there were corresponding significant changes in molecules associated with EMT. PAK2 facilitated the angiogenic potential of cancer cells and promotes the epithelial-mesenchymal transition process by activating the TGF-beta signaling pathway. Simultaneously, it decreased the differentiation level of cancer cells, consequently enhancing their malignancy. Additionally, PAK2 fostered communication between cancer cells and the tumor microenvironment, augments cancer cell chemoresistance, and modulates energy metabolism pathways. In summary, PAK2 emerged as a pivotal gene orchestrating pancreatic cancer liver metastasis. Intervening in the expression of PAK2 may offer a promising therapeutic strategy for preventing liver metastasis of pancreatic cancer and improving its prognosis.

LINC01852 inhibits the tumorigenesis and chemoresistance in colorectal cancer by suppressing SRSF5-mediated alternative splicing of PKM

BackgroundColorectal cancer (CRC) is a major cause of cancer-related deaths worldwide, and chemoresistance is a major obstacle in its treatment. Despite advances in therapy, the molecular mechanism underlying chemoresistance in CRC is not fully understood. Recent studies have implicated the key roles of long noncoding RNAs (lncRNAs) in the regulation of CRC chemoresistance.MethodsIn this study, we investigated the role of the lncRNA LINC01852 in CRC chemoresistance. LINC01852 expression was evaluated in multiple CRC cohorts using quantitative reverse transcription PCR. We conducted in vitro and in vivo functional experiments using cell culture and mouse models. RNA pull-down, RNA immunoprecipitation, chromatin immunoprecipitation, and dual luciferase assays were used to investigate the molecular mechanism of LINC01852 in CRC.ResultsOur findings revealed that a lncRNA with tumor-inhibiting properties, LINC01852, was downregulated in CRC and inhibited cell proliferation and chemoresistance both in vitro and in vivo. Further mechanistic investigations revealed that LINC01852 increases TRIM72-mediated ubiquitination and degradation of SRSF5, inhibiting SRSF5-mediated alternative splicing of PKM and thereby decreasing the production of PKM2. Overexpression of LINC01852 induces a metabolic switch from aerobic glycolysis to oxidative phosphorylation, which attenuates the chemoresistance of CRC cells by inhibiting PKM2-mediated glycolysis.ConclusionsOur results demonstrate that LINC01852 plays an important role in repressing CRC malignancy and chemoresistance by regulating SRSF5-mediated alternative splicing of PKM, and that targeting the LINC01852/TRIM72/SRSF5/PKM2 signaling axis may represent a potential therapeutic strategy for CRC.

Effects of free fatty acid receptor (FFAR) signaling on the modulation of cancer cell functions under hypoxic conditions

In the tumor environment, hypoxia promotes tumor progression, such as cancer cell growth, migration and chemoresistance. This study aimed to evaluate the roles of free fatty acid receptors (FFARs) in the regulation of cancer cell functions under hypoxic conditions, using fibrosarcoma HT1080 cells. HT1080 cells expressed FFAR1, FFAR2 and FFAR3 genes, but not FFAR4 gene. FFAR1, FFAR2 and FFAR3 expression levels in HT1080 cells cultured at 1 % O2 were elevated, compared with 21 % O2. The cell growth activities of HT1080 cells cultured at 21 % O2 were inhibited by acetic acid (AA) and propanoic acid (PA), but not 1 % O2. HT1080 cell motility was markedly reduced by culturing at 1 % O2. The cell growth and motility of HT1080 cells were enhanced by FFAR2 knockdown. The cell viability to cisplatin (CDDP) of HT1080 cells cultured at 1 % O2 was increased, compared with 21 % O2. FFAR2 knockdown suppressed the cell viability to CDDP of HT1080 cells. On the other hand, the cell motility and viability to CDDP of HT1080 cells cultured at 21 % O2 were suppressed by TUG-770. When HT1080 cells were cultured at 1 % O2, the cell motility and viability to CDDP were decreased, correlating with FFAR1 expression level. Moreover, FFAR1 knockdown increased the cell viability to CDDP of HT1080 cells cultured at 1 % O2. These results suggest that FFAR-mediated signaling plays an important role in the modulation of cellular functions of HT1080 cells under hypoxic conditions.

Therapeutic Chemoresistance in Ovarian Cancer: Emerging Hallmarks, Signaling Mechanisms and Alternative Pathways.

Ovarian cancer is the fifth leading cause of mortality and the most lethal gynecologic malignancy among females. It may arise from atypical borderline tumors (Type I) or serous tubal intraepithelial carcinoma (Type II). The diagnosis of cancer at its early stages is difficult because of non-specific symptoms, most patients are diagnosed at the advanced stage. Several drugs and therapeutic strategies are available to treat ovarian cancer such as surgery, chemotherapy, neoadjuvant therapy, and maintenance therapy. However, the cancer cells have developed resistance to a number of available therapies causing treatment failure. This emerging chemoresistance in ovarian cancer cells is becoming an obstacle due to alterations in multiple cellular processes. These processes involve altered drug target response, drug pumps, detoxification systems, lower sensitivity to apoptosis, and altered proliferation, and are responsible for developing resistance to anticancer medicines. Various research reports have evidenced that these altered processes might play a role in the emergence of resistance. This review addresses the recent advances in understanding the underlying mechanisms of ovarian cancer resistance and covers sophisticated alternative pathways to overcome these resistance mechanisms in patients.

Neoadjuvant chemotherapy-induced remodeling of human hormonal receptor-positive breast cancer revealed by single-cell RNA sequencing

Hormone receptor-positive breast cancer (HR+ BC) is known to be relatively insensitive to chemotherapy, and since chemotherapy has remained the major neoadjuvant therapy for HR+ BC, the undetermined mechanism of chemoresistance and how chemotherapy reshapes the immune microenvironment need to be explored by high-throughput technology. By using single-cell RNA sequencing and multiplexed immunofluorescence staining analysis of HR+ BC samples (paired pre- and post-neoadjuvant chemotherapy (NAC)), the levels of previously unrecognized immune cell subsets, including CD8+ T cells with pronounced expression of T-cell development (LMNA) and cytotoxicity (FGFBP2) markers, CD4+ T cells characterized by proliferation marker (ATP1B3) expression and macrophages characterized by CD52 expression, were found to be increased post-NAC, which were predictive of chemosensitivity and their antitumor function was also validated with in vitro experiments. In terms of immune checkpoint expression of CD8+ T cells, we found their changes were inconsistent post-NAC, that LAG3, VSIR were decreased, and PDCD1, HAVCR2, CTLA4, KLRC1 and BTLA were increased. In addition, we have identified novel genomic and transcriptional patterns of chemoresistant cancer cells, both innate and acquired, and have confirmed their prognostic value with TCGA cohorts. By shedding light on the ecosystem of HR+ BC reshaped by chemotherapy, our results uncover valuable candidates for predicting chemosensitivity and overcoming chemoresistance in HR+ BC.

The facilitating effects of KRT80 on chemoresistance, lipogenesis, and invasion of esophageal cancer

ABSTRACT Keratin 80 (KRT80) is a filament protein that makes up one of the major structural fibers of epithelial cells, and involved in cell differentiation and epithelial barrier integrity. Here, KRT80 mRNA expression was found to be higher in esophageal cancer than normal epithelium by RT-PCR and bioinformatics analysis (p < .05), opposite to KRT80 methylation (p < .05). There was a negative relationship between promoter methylation and expression level of KRT80 gene in esophageal cancer (p < .05). KRT80 mRNA expression was positively correlated with the differentiation, infiltration of immune cells, and poor prognosis of esophageal cancer (p < .05). KRT80 mRNA expression was positively linked to no infiltration of immune cells, the short survival time of esophageal cancers (p < .05). The differential genes of KRT80 mRNA were involved in fat digestion and metabolism, peptidase inhibitor, and intermediate filament, desosome, keratinocyte differentiation, epidermis development, keratinization, ECM regulator, complement cascade, metabolism of vitamins and co-factor (p < .05). KRT-80-related genes were classified into endocytosis, cell adhesion molecule binding, cadherin binding, cell–cell junction, cell leading edge, epidermal cell differentiation and development, T cell differentiation and receptor complex, plasma membrane receptor complex, external side of plasma membrane, metabolism of amino acids and catabolism of small molecules, and so forth (p < .05). KRT80 knockdown suppressed anti-apoptosis, anti-pyroptosis, migration, invasion, chemoresistance, and lipogenesis in esophageal cancer cells (p < .05), while ACC1 and ACLY overexpression reversed the inhibitory effects of KRT80 on lipogenesis and chemoresistance. These findings indicated that up-regulated expression of KRT80 might be involved in esophageal carcinogenesis and subsequent progression, aggravate aggressive phenotypes, and induced chemoresistance by lipid droplet assembly and ACC1- and ACLY-mediated lipogenesis.

A partial epithelial-mesenchymal transition signature for highly aggressive colorectal cancer cells that survive under nutrient restriction.

Partial epithelial-mesenchymal transition (p-EMT) has recently been identified as a hybrid state consisting of cells with both epithelial and mesenchymal characteristics and is associated with the migration, metastasis, and chemoresistance of cancer cells. Here, we describe the induction of p-EMT in starved colorectal cancer (CRC) cells and identify a p-EMT gene signature that can predict prognosis. Functional characterisation of starvation-induced p-EMT in HCT116, DLD1, and HT29 cells showed changes in proliferation, morphology, and drug sensitivity, supported by in vivo studies using the chorioallantoic membrane model. An EMT-specific quantitative polymerase chain reaction (qPCR) array was used to screen for deregulated genes, leading to the establishment of an in silico gene signature that was correlated with poor disease-free survival in CRC patients along with the CRC consensus molecular subtype CMS4. Among the significantly deregulated p-EMT genes, a triple-gene signature consisting of SERPINE1, SOX10, and epidermal growth factor receptor (EGFR) was identified. Starvation-induced p-EMT was characterised by increased migratory potential and chemoresistance, as well as E-cadherin processing and internalisation. Both gene signature and E-cadherin alterations could be reversed by the proteasomal inhibitor MG132. Spatially resolving EGFR expression with high-resolution immunofluorescence imaging identified a proliferation stop in starved CRC cells caused by EGFR internalisation. In conclusion, we have gained insight into a previously undiscovered EMT mechanism that may become relevant when tumour cells are under nutrient stress, as seen in early stages of metastasis. Targeting this process of tumour cell dissemination might help to prevent EMT and overcome drug resistance. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Abstract C067: Correlation of keratin17 expression with tumor cell proliferation and invasion in PDAC

Abstract Background: Pancreatic ductal adenocarcinoma (PDAC) shows variable degrees of differentiation, with both intratumoral, regional, and case to case heterogeneity, including glandular elements, sheet-like aggregates, cell clusters, and single diffusely infiltrative tumor cells. Prior research from our lab and others have established keratin 17 (K17) to be a defining hallmark of the basal molecular subtype of PDAC. In addition to its role as a component of the cytoskeleton, soluble forms of K17 undergo nuclear translocation to drive cell cycle progression and chemoresistance to first line chemotherapy. While K17 is heterogeneously expressed in the gland-forming elements of PDACs, it is most consistently expressed in tumor cells which are either in small groups or are single diffusely infiltrative. The aims of the current study are to define the correlation between K17 expression and tumor cell differentiation, with the focus on glandular versus single diffusely infiltrative components of PDAC, and to relate these findings to established biomarkers of cell proliferation and invasion. Methods: Archival human PDACs were provided by the Stony Brook Cancer Center Biobank and K17 immunohistochemistry was performed by indirect immunoperoxidase method, as previously described, to select cases with both glandular and diffusely infiltrative cell components and heterogeneous K17 expression. Multiplex immunofluorescence with a panel of antibodies to K17 (Cell Signaling Technology), pan-cytokeratin, Ki-67 and vimentin [KS1] (Miltenyi Biotec) was performed on 5-micron FFPE sections using the MACSima system (Miltenyi Biotec). Distribution patterns of K17 were evaluated in glandular and diffusely invasive components and were related to the Ki-67 status. Results: Cytoplasmic staining for K17 was found in the minority of tumor cells in glands and displayed intraglandular heterogeneity but was found in most diffusely infiltrative tumor cells. Also, nuclear K17 was rarely detected in the glandular components but was found in a high proportion of the diffusely infiltrative cells. Ki-67 was detected mainly in glandular cells, unrelated to K17 status, and rarely in single diffusely infiltrative cells, never co-localizing with nuclear K17. Of note, only a small fraction of tumor cells co-expressed K17 and vimentin, suggesting that majority of diffusely infiltrative tumor cells were not engaged in epithelial to mesenchymal transition. Conclusion: While cytoplasmic K17 is heterogeneously expressed in the glandular components of PDAC, strong staining for K17 in both the cytoplasm and the nucleus is a hallmark of diffusely infiltrative, Ki-67-negative tumor cells. These observations support the paradigm that tumor cells are committed to either cell division in the glandular components, or to diffuse single cell invasion, highlighted by increased cytoplasmic and nuclear K17 expression. Therefore, the results emphasize the importance of understanding the expression of PDAC biomarkers in both gland-forming elements and diffusely infiltrative tumor cells. Citation Format: Shayan Sarkar, Lyanne Oblein, Michael Horowitz, Luisa Escobar-Hoyos, Natalia Marchenko, Kenneth Shroyer. Correlation of keratin17 expression with tumor cell proliferation and invasion in PDAC [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr C067.

Inhibition of mitochondrial function by approved drugs overcomes nasopharyngeal carcinoma chemoresistance.

The development of chemo-resistance in nasopharyngeal carcinoma (NPC) presents a significant therapeutic challenge, and its underlying mechanisms remain poorly understood. In our previous studies, we highlighted the association between isoprenylcysteine carboxylmethyltransferase (ICMT) and chemoresistance in NPC. In this current research, we revealed that both 5-FU and cisplatin-resistant NPC cells exhibited elevated mitochondrial function and increased expression of mitochondrial genes, independent of ICMT. Our investigations further showed that classic mitochondrial inhibitors, such as oligomycin, antimycin, and rotenone, were notably more effective in reducing viability in chemo-resistant NPC cells compared to parental cells. Moreover, we identified two antimicrobial drugs, tigecycline and atovaquone, recognized as mitochondrial inhibitors, as potent agents for decreasing chemo-resistant NPC cells by targeting mitochondrial respiration. Remarkably, tigecycline and atovaquone, administered at tolerable doses, inhibited chemo-resistant NPC growth in mouse models and extended overall survival rates. This work unveils the efficacy of mitochondrial inhibition as a promising strategy to overcome chemo-resistance in NPC. Additionally, our findings highlight the potential repurposing of clinically available drugs like tigecycline and atovaquone for treating NPC patients who develop chemoresistance.

Exploring the importance of kynurenine pathway (KP) approaches in colorectal cancer (CRC)

One of the main causes of cancer-related fatalities is colorectal cancer (CRC). The majority of patients frequently receive a late diagnosis of colorectal cancer (CRC) due to the absence of accurate prognostic and predictive biomarkers. Furthermore, greater metastasis and shorter survival rates were seen in colorectal cancer (CRC) patients. Recent advances in cancer treatment have been made possible by therapeutic immune system potentiation. The immune system and the kynurenine pathway (KP) are closely related. As a result of kynurenine's promotion of T Reg (regulatory) differentiation, more anti-inflammatory cytokines are produced and the cytotoxic activity of T cells is suppressed. In malignancies, the overactivation of the kynurenine pathway (KP) creates a micro environment where mutant cells can survive and invade neighboring tissues.The poor prognosis of several cancers, including gastrointestinal cancers, gynecological cancers, hematologic malignancies, breast cancer, lung cancer, glioma, melanoma, prostate cancer, and pancreatic cancer, is predicted by overactivation of the kynurenine pathway (KP), particularly the overactivation of indoleamine 2,3-dioxygenase (IDO). Additionally, kynurenine promotes cancer cell invasion, metastasis, and chemoresistance. The evolving understanding of the kynurenine pathway (KP) and its use in colorectal cancer (CRC) is covered in this review. An essential amino acid called tryptophan can be processed by several different pathways, with the kynurenine pathway (KP) being one of the more important ones. Kynurenine (KYN) is recognized as an oncometabolite in colon cancer, and colorectal cancer (CRC) that results from its subsequent metabolites. For several physiological activities, indoleamine 2,3-dioxygenase (IDO), a crucial enzyme that catalyzes kynurenine metabolism, is required. We talked about IDO's role in colorectal cancer (CRC) in this review. IDO knockdown decreased the expression of cancer stem cell markers as well as the ability of colorectal cancer (CRC) cells to migrate and invade. The application of an inhibitor to restrict the enzymatic activity of IDO also prevented the formation of spheres and hindered cell motility in colorectal cancer (CRC) cells. These findings demonstrate the clinical significance of IDO in the growth and tumorigenicity of colorectal cancer (CRC) tumors.

NRP1 Induces Enhanced Stemness and Chemoresistance in Glioma Cells via YAP.

Neuropilin-1 (NRP1), a transmembrane glycoprotein, plays an important role in the malignant progression of gliomas; however, its role in chemoresistance is not fully understood. In this study, we observed the effects of NRP1 on the stemness and chemoresistance of glioma cells and the mediating role of Yes-associated protein (YAP). We constructed NRP1 overexpressing LN-229 glioma cells. Cells were treated with recombinant NRP1 protein (rNRP1) and the YAP inhibitor Super-TDU when necessary. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to detect the sensitivity of cells to temozolomide (TMZ). Sphere and clone formation assays were performed to detect the sphere- and clone-forming abilities of cells. Western blotting was performed to detect cellular CD133, CD44, p-LATS1, and p-YAP protein expression. Immunofluorescence and flow cytometry were used to detect the subcellular localization of YAP and apoptosis, respectively. We found that both NRP1 overexpression and rNRP1 treatment enhanced self-renewal, TMZ resistance, and CD133 and CD44 protein expression in LN-229 cells. NRP1 overexpression and rNRP1 treatment also induced LATS1 and YAP dephosphorylation and YAP nuclear translocation. Super-TDU inhibits NRP1 overexpression-induced enhanced self-renewal and TMZ resistance in LN-229 cells. Our study suggests that NRP1 induces increased stemness in glioma cells, resulting in chemoresistance, and that this effect is associated with YAP activation.

Exosomes derived from cancer-associated fibroblasts promote tumorigenesis, metastasis and chemoresistance of colorectal cancer by upregulating circ_0067557 to target Lin28

BackgroundCancer associated fibroblasts (CAFs) can remodel tumor microenvironment by secreting exosomes. This study aimed to investigate the role of exosomes derived from cancer-associated fibroblasts in colorectal cancer (CRC) progression.MethodsCircular RNA (circRNA) array was used to identify differentially expressed circRNAs in exosomes from normal fibroblasts (NFs) and CAFs, and confirmed one differentially expressed circRNA circ_0067557 by real-time PCR. The effect of circ_0067557 on proliferation, metastasis, chemoresistance and apoptosis was verified by wound heal, tranwell, CCK8, sphere-forming and flow cytometry assay.ResultsCirc_0067557 expression in exosomes from CAFs was higher than those from NFs. CAF-derived exosomes promoted the proliferation, migration, invasion and chemoresistance of CRC cells while suppressed apoptosis. Silencing of circ_0067557 inhibited malignant phenotypes of CRC cells by targeting Lin28A and Lin28B. Moreover, CAF-derived exosomes enhanced the growth of CRC xenograft tumors.ConclusionCirc_0067557/Lin28A and Lin28B signal axis may be a potential therapy target for CRC.

New retinoblastoma (RB) drug delivery approaches: anti-tumor effect of atrial natriuretic peptide (ANP)-conjugated hyaluronic-acid-coated gold nanoparticles for intraocular treatment of chemoresistant RB.

Intraocular drug delivery is a promising approach for treatment of ocular diseases. Chemotherapeutic drugs used in retinoblastoma (RB) treatment often lead to side effects and drug resistances. Therefore, new adjuvant therapies are needed to treat chemoresistant RBs. Biocompatible gold nanoparticles (GNPs) have unique antiangiogenic properties and can inhibit cancer progression. The combination of gold and low-molecular-weight hyaluronan (HA) enhances the stability of GNPs and promotes the distribution across ocular barriers. Attached to HA-GNPs, the atrial natriuretic peptide (ANP), which diminishes neovascularization in the eye, is a promising new therapeutic agent for RB treatment. In the study presented, we established ANP-coupled HA-GNPs and investigated their effect on the tumor formation potential of chemoresistant RB cells in an in ovo chicken chorioallantoic membrane model and an orthotopic in vivo RB rat eye model. Treatment of etoposide-resistant RB cells with ANP-HA-GNPs in ovo resulted in significantly reduced tumor growth and angiogenesis compared with controls. The antitumorigenic effect could be verified in the rat eye model, including a noninvasive application form via eye drops. Our data suggest that ANP-HA-GNPs represent a new minimally invasive, adjuvant treatment option for RB.

Extracellular vesicles released by hypoxia-induced tumor-associated fibroblasts impart chemoresistance to breast cancer cells via long noncoding RNA H19 delivery.

Recently, extracellular vesicles (EVs) have been emphasized in regulating the hypoxic tumor microenvironment of breast cancer (BC), where tumor-associated fibroblasts (TAFs) play a significant role. In this study, we describe possible molecular mechanisms behind the pro-tumoral effects of EVs, secreted by hypoxia (HP)-induced TAFs, on BC cell growth, metastasis, and chemoresistance. These mechanisms are based on long noncoding RNA H19 (H19) identified by microarray analysis. We employed an in silico approach to identify differentially expressed lncRNAs that were associated with BC. Subsequently, we explored possible downstream regulatory mechanisms. We isolated EVs from TAFs that were exposed to HP, and these EVs were denoted as HP-TAF-EVs henceforth. MTT, transwell, flow cytometry, and TUNEL assays were performed to assess the malignant phenotypes of BC cells. A paclitaxel (TAX)-resistant BC cell line was constructed, and xenograft tumor and lung metastasis models were established in nude mice for invivo verification. Our observation revealed that lncRNA H19 was significantly overexpressed, whereas miR-497 was notably downregulated in BC. HP induced activation of TAFs and stimulated the secretion of EVs. Coculture of HP-TAF-EVs and BC cells led to an increase in TAX resistance of the latter. HP-TAF-EVs upregulated methylation of miR-497 by delivering lncRNA H19, which recruited DNMT1, thus lowering the expression of miR-497. In addition, lncRNA H19-containing HP-TAF-EVs hindered miR-497 expression, enhancing tumorigenesis and TAX resistance of BC cells invivo. Our study presents evidence for the contribution of lncRNA H19-containing HP-TAF-EVs in the reduction of miR-497 expression through the recruitment of DNMT1, which in turn promotes the growth, metastasis, and chemoresistance of BC cells.

DNA-PK-Mediated Cytoplasmic DNA Sensing Stimulates Glycolysis to Promote Lung Squamous Cell Carcinoma Malignancy and Chemoresistance.

DNA-PK is a cytoplasmic DNA sensor that activates ZAK/AKT/mTOR signaling and boosts glycolysis to enhance malignancy and chemoresistance of lung squamous cell carcinoma.

N6-methyladenosine-modified circPLPP4 sustains cisplatin resistance in ovarian cancer cells via PIK3R1 upregulation

BackgroundCisplatin (CDDP) is the first-line chemotherapeutic strategy to treat patients with ovarian cancer (OC). The development of CDDP resistance remains an unsurmountable obstacle in OC treatment and frequently induces tumor recurrence. Circular RNAs (circRNAs) are noncoding RNAs with important functions in cancer progression. Whether circRNAs function in CDDP resistance of OC is unclear.MethodsPlatinum-resistant circRNAs were screened via circRNA deep sequencing and examined using in situ hybridization (ISH) in OC. The role of circPLPP4 in CDDP resistance was assessed by clone formation and Annexin V assays in vitro, and by OC patient-derived xenografts and intraperitoneal tumor models in vivo. The mechanism underlying circPLPP4-mediated activation of miR-136/PIK3R1 signaling was examined by luciferase reporter assay, RNA pull-down, RIP, MeRIP and ISH.ResultscircPLPP4 was remarkably upregulated in platinum resistant OC. circPLPP4 overexpression significantly enhanced, whereas circPLPP4 silencing reduced, OC cell chemoresistance. Mechanistically, circPLPP4 acts as a microRNA sponge to sequester miR-136, thus competitively upregulating PIK3R1 expression and conferring CDDP resistance. The increased circPLPP4 level in CDDP-resistant cells was caused by increased RNA stability, mediated by increased N6-methyladenosine (m6A) modification of circPLPP4. In vivo delivery of an antisense oligonucleotide targeting circPLPP4 significantly enhanced CDDP efficacy in a tumor model.ConclusionsOur study reveals a plausible mechanism by which the m6A -induced circPLPP4/ miR-136/ PIK3R1 axis mediated CDDP resistance in OC, suggesting that circPLPP4 may serve as a promising therapeutic target against CDDP resistant OC. A circPLPP4-targeted drug in combination with CDDP might represent a rational regimen in OC.

The clinical implication and translational research of OSCC differentiation.

The clinical value and molecular characteristics of tumor differentiation in oral squamous cell carcinoma (OSCC) remain unclear. There is a lack of a related molecular classification prediction system based on pathological images for precision medicine. Integration of epidemiology, genomics, experiments, and deep learning to clarify the clinical value and molecular characteristics, and develop a novel OSCC molecular classification prediction system. Large-scale epidemiology data (n = 118,817) demonstrated OSCC differentiation was a significant prognosis indicator (p < 0.001), and well-differentiated OSCC was more chemo-resistant than poorly differentiated OSCC. These results were confirmed in the TCGA database and in vitro. Furthermore, we found chemo-resistant related pathways and cell cycle-related pathways were up-regulated in well- and poorly differentiated OSCC, respectively. Based on the characteristics of OSCC differentiation, a molecular grade of OSCC was obtained and combined with pathological images to establish a novel prediction system through deep learning, named ShuffleNetV2-based Molecular Grade of OSCC (SMGO). Importantly, our independent multi-center cohort of OSCC (n = 340) confirmed the high accuracy of SMGO. OSCC differentiation was a significant indicator of prognosis and chemotherapy selection. Importantly, SMGO could be an indispensable reference for OSCC differentiation and assist the decision-making of chemotherapy.

Pan-EGFR Inhibitor Dacomitinib Resensitizes Paclitaxel and Induces Apoptosis via Elevating Intracellular ROS Levels in Ovarian Cancer SKOV3-TR Cells.

Paclitaxel is still used as a standard first-line treatment for ovarian cancer. Although paclitaxel is effective for many types of cancer, the emergence of chemoresistant cells represents a major challenge in chemotherapy. Our study aimed to analyze the cellular mechanism of dacomitinib, a pan-epidermal growth factor receptor (EGFR) inhibitor, which resensitized paclitaxel and induced cell cytotoxicity in paclitaxel-resistant ovarian cancer SKOV3-TR cells. We investigated the significant reduction in cell viability cotreated with dacomitinib and paclitaxel by WST-1 assay and flow cytometry analysis. Dacomitinib inhibited EGFR family proteins, including EGFR and HER2, as well as its downstream signaling proteins, including AKT, STAT3, ERK, and p38. In addition, dacomitinib inhibited the phosphorylation of Bad, and combination treatment with paclitaxel effectively suppressed the expression of Mcl-1. A 2'-7'-dichlorodihydrofluorescein diacetate (DCFH-DA) assay revealed a substantial elevation in cellular reactive oxygen species (ROS) levels in SKOV3-TR cells cotreated with dacomitinib and paclitaxel, which subsequently mediated cell cytotoxicity. Additionally, we confirmed that dacomitinib inhibits chemoresistance in paclitaxel-resistant ovarian cancer HeyA8-MDR cells. Collectively, our research indicated that dacomitinib effectively resensitized paclitaxel in SKOV3-TR cells by inhibiting EGFR signaling and elevating intracellular ROS levels.