Molecular mechanisms associated with chemoresistance in esophageal cancer

Inhibition of JAK2/STAT3 by pacritinib synergizes with chemotherapy in esophageal carcinoma

The poor outcomes associated with esophageal carcinoma, particularly in advanced stages, necessitate the development of new treatment strategies. This study examines the efficacy of pacritinib, a multi-kinase inhibitor, both alone and in combination with carboplatin, in preclinical esophageal carcinoma models. Six esophageal carcinoma cell lines (KYSE-70, OE33, FLO-1, KYAE-1, ESO 26, and HCE-6) were treated with pacritinib, resulting in a dose-dependent reduction in cell viability. Combination index (CI) analysis demonstrated strong synergy between pacritinib and carboplatin across this panel of cell lines. In in vivo esophageal carcinoma xenograft model, pacritinib alone significantly reduced tumor growth and improved survival rates compared to control. Notably, the combination of pacritinib and carboplatin further reduced tumor growth and improved survival rates compared to either treatment alone. Toxicity assessment showed that neither single-agent nor combination treatment resulted in significantly altered levels of body weight and serum markers, supporting the safety profile of pacritinib in combination with carboplatin. Mechanistic studies revealed that while pacritinib inhibited the phosphorylation of JAK, STAT3, and IRAK1 in esophageal carcinoma cells, it is the suppression of the JAK/STAT3 pathway, rather than IRAK1, that is responsible for the synergistic effect with carboplatin. Our findings indicate that pacritinib possesses potent anti-tumor activity in esophageal carcinoma and enhances the efficacy of carboplatin through the suppression of JAK/STAT3 signaling, warranting further clinical investigation.

Nitric oxide synthase 1 inhibits the progression of esophageal cancer through interacting with nitric oxide synthase 1 adaptor protein

BACKGROUND

Esophageal cancer (ESCA) is among the most prevalent and lethal tumors globally. While nitric oxide synthase 1 (NOS1) is recognized for its important involvement in various cancers, its specific function in ESCA remains unclear.

AIM

To explore the potential role and underlying mechanisms of NOS1 in ESCA.

METHODS

Survival rates were analyzed using GeneCards and Gene Expression Profiling Interactive Analysis. The effects and mechanisms of NOS1 on ESCA cells were evaluated via the Cell Counting Kit-8 assay, scratch assay, Transwell assay, flow cytometry, quantitative polymerase chain reaction, western blotting, and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling staining. The protein interaction network was used to screen the interacting proteins of NOS1 and validate these interactions through co-immunoprecipitation and dual luciferase assays. Additionally, a nude mouse xenograft model was established to evaluate the effect of NOS1 in vivo.

RESULTS

The survival rate of patients with ESCA with high NOS1 expression was higher than that of patients with low NOS1 expression. NOS1 expression in ESCA cell lines was lower than that in normal esophageal epithelial cells. Overexpression of NOS1 (oe-NOS1) inhibited proliferation, invasion, and migration abilities in ESCA cell lines, resulting in decreased autophagy levels and increased apoptosis, pyroptosis, and ferroptosis. Protein interaction studies confirmed the interaction between NOS1 and NOS1 adaptor protein (NOS1AP). Following oe-NOS1 and the silencing of NOS1AP, levels of P62 and microtubule-associated protein 1 light chain 3 beta increased both in vitro and in vivo. Furthermore, the expression levels of E-cadherin, along with the activation of phosphatidylinositol 3-kinase (PI3K) and protein kinase B (AKT), were inhibited in ESCA cell lines.

CONCLUSION

NOS1 and NOS1 proteins interact to suppress autophagy, activate the PI3K/AKT pathway, and exert anti-cancer effects in ESCA.

Emerging role of deubiquitinases in modulating cancer chemoresistance

Chemotherapy remains a gold standard in cancer treatment by targeting the rapidly dividing cancer cells. However, chemoresistance is a major obstacle to successful cancer treatment, often leading to recurrence, metastasis, and high mortality. Deubiquitinases (DUBs), enzymes that remove ubiquitin and stabilize proteins, have been implicated in chemoresistance and can either promote therapeutic resistance or enhance sensitivity depending on their targets. In this review, we highlight the chemoresistance mechanisms of DUBs in various cancers, including breast, lung, liver, gastrointestinal, colorectal, ovarian, prostate, and blood cancers. Given these mechanisms, the development of DUB inhibitors has gained considerable attention in cancer therapeutics and combination therapies involving these inhibitors show potential to overcome drug resistance and improving treatment outcomes.

Associations between vascular endothelial growth factor polymorphisms and response to 5-FU-based pharmaceutical therapy in esophageal squamous cell carcinoma: A meta-analysis

BACKGROUND AND AIMS

Vascular endothelial growth factor (VEGF) gene polymorphisms are associated with the response to pharmaceutical therapy in many cancers. This study aimed to investigate the effects of VEGF gene polymorphisms in esophageal squamous cell carcinoma patients receiving pharmaceutical therapy.

METHODS

This literature-based meta-analysis was performed with keywords related to VEGF gene polymorphisms and clinical response in esophageal squamous carcinoma patients receiving pharmaceutical therapy (including 5-FU, cisplatin, oxaliplatin, and calcium folinate). After a series of bias grading analyses and DerSimonian-Laird method analysis, odds ratios and 95% confidence intervals were calculated to examine the potential relationships. Sensitivity and subgroup analyses were subsequently performed to determine the major causes of heterogeneity.

RESULTS

Heterogeneity was dramatically reduced after the removal of one study from the analysis (I2 = 37%, P = 0.19). The remaining studies involved 5-FU-based treatment. The presence of VEGF G-1154A and VEGF-634C/G was found to be correlated with patient response to 5-FU/CDDP-based treatment, whereas VEGF-2549I/D was correlated with response to 5-FU/oxaliplatin-based treatment, and VEGF-936C/T was associated with both 5-FU/CDDP- and 5-FU/oxaliplatin-based treatment response.

CONCLUSION

VEGF gene polymorphisms affect the response of esophageal squamous carcinoma patients receiving pharmaceutical therapy, especially 5-FU-based treatments.

Cell-based immunotherapy in oesophageal cancer

Oesophageal cancer (EC) is among the most common illnesses globally, and its prognosis is unfavourable. Surgery, radiotherapy and chemotherapy are the primary therapy options for EC. Despite the occasional efficacy of these traditional treatment modalities, individuals with EC remain at a significant risk for local recurrence and metastasis. Consequently, innovative and efficacious medicines are required. In recent decades, clinical practice has effectively implemented cell therapy, which includes both stem cell and non-stem cell-based approaches, as an innovative tumour treatment, offering renewed hope to patients with oesophageal squamous cell carcinoma (ESCC). This paper examines the theoretical framework and contemporary advancements in cell treatment for individuals with EC. We further described current clinical studies and summarised essential data related to survival and safety assessments.

Shared chemoresistance genes in ESCC and cervical Cancer: Insights from pharmacogenomics and Mendelian randomization

BACKGROUND

Neoadjuvant chemotherapy, particularly the use of platinum-based compounds and taxanes, is pivotal in the treatment of epithelial-derived tumors, such as cervical cancer and esophageal squamous cell carcinoma (ESCC); however, resistance remains a significant challenge. Utilizing Mendelian randomization (MR) with pharmacogenomics offers a novel approach to understanding the genetic underpinnings of drug responses, thereby aiding in personalized treatment.

METHODS

Single-cell RNA sequencing (scRNA-seq) analysis revealed a shared cellular subpopulation of CD8 + T effector memory (CD8 + TEM) cells that are pivotal in mediating chemotherapy resistance in ESCC and cervical cancer. A two-sample approach was employed for MR using data from genome-wide association studies, focusing on single nucleotide polymorphisms (SNPs) linked to CD8 + TEM cell expression. The SNPs were carefully selected, and statistical models, including the Wald ratio and inverse variance weighted methods, were used for robust causal effect estimation. These were supplemented by MR-Egger and weighted median analyses to address pleiotropy and variant heterogeneity. 3-(4,5-Dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide (MTT) and immunohistochemistry assays were used to verify the relationship between the gene and drug sensitivity.

RESULTS

Increased proportion of CD8 + TEM cells were observed in resistant samples. MR identified IL32, SPOCK1, and TRBC2 as key genes associated with resistance to cisplatin, carboplatin, and paclitaxel, respectively. These findings were validated across various cohorts and underscored the role of CD8 + TEM cells in drug responsiveness. The results of the MTT and immunohistochemistry assays confirmed the MR findings.

CONCLUSIONS

Our study highlights the significant role of CD8 + TEM cells in the chemoresistance of ESCC and cervical cancer and identified three genetic markers crucial for resistance to common chemotherapeutic agents. These findings suggest potential pathways for developing personalized treatment strategies, offering clinically relevant insights that could enhance therapeutic efficacy and help overcome drug resistance in patients with ESCC or cervical cancer.

Exploring metabolic reprogramming in esophageal cancer: the role of key enzymes in glucose, amino acid, and nucleotide pathways and targeted therapies

Esophageal cancer (EC) is one of the most common malignancies worldwide with the character of poor prognosis and high mortality. Despite significant advancements have been achieved in elucidating the molecular mechanisms of EC, for example, in the discovery of new biomarkers and metabolic pathways, effective treatment options for patients with advanced EC are still limited. Metabolic heterogeneity in EC is a critical factor contributing to poor clinical outcomes. This heterogeneity arises from the complex interplay between the tumor microenvironment and genetic factors of tumor cells, which drives significant metabolic alterations in EC, a process known as metabolic reprogramming. Understanding the mechanisms of metabolic reprogramming is essential for developing new antitumor therapies and improving treatment outcomes. Targeting the distinct metabolic alterations in EC could enable more precise and effective therapies. In this review, we explore the complex metabolic changes in glucose, amino acid, and nucleotide metabolism during the progression of EC, and how these changes drive unique nutritional demands in cancer cells. We also evaluate potential therapies targeting key metabolic enzymes and their clinical applicability. Our work will contribute to enhancing knowledge of metabolic reprogramming in EC and provide new insights and approaches for the clinical treatment of EC.

Exosomal miR-130a-3p confers cisplatin resistance in esophageal cancer by regulating ferroptosis via the suppression of METTL14-mediated m6A RNA methylation of FSP1

Exosomal microRNA (miRNA)s have been proven to affect recipient cell chemoresistance in several cancers. This research attempted to uncover the role of exosomal miRNA and the regulatory mechanism in cisplatin resistance of esophageal cancer (EC). Cisplatin-resistant EC cells (KYSE-150-CisR and TE-1-CisR) were established by the parental cells (KYSE-150 and TE-1) treated with a gradual increase of cisplatin concentration. Exosomes from both cisplatin-resistant EC cells and the parental one were obtained with ultracentrifugation (CisR-exo and CisS-exo), and identified by transmission electron microscopy and nanoparticle tracking analysis. The effect of CisR-exo on the cisplatin resistance of EC was assessed by in vitro (and in vivo functional experiments.Intracellular reactive oxygen species and iron were determined by the corresponding kits. The m6A dot blot assay and methylated RIP-qPCR was conducted to analyze the m6A modification level. Dual-luciferase reporter assay was performed to confirm the intermolecular interaction. Increased levels of miR-130a-3p were observed in both KYSE-150CisR and TE-1CisR cells, as well as their derived CisR-exos when compared with the parental cells and CisS-exos. Exosomal miR-130a-3p from cisplatin-resistant EC cells conferred cisplatin resistance to EC in vitro and in vivo, which might be mediated by the suppression of ferroptosis. Mechanically, KYSE-150CisR derived exosomal miR-130a-3p interacted with METTL14 to inhibit FSP1 (a ferroptosis suppressor) m6A modification of recipient cells. Overexpressing METTL14 restrained the cisplatin resistance disseminated by CisR-exos in KYSE-150 cells. Cisplatin-resistant EC cell-isolated exosomal miR-130a-3p suppressed the m6A modification of FSP1 to modulate ferroptosis, enhancing cisplatin resistance.

Nanoparticle delivery of si-Notch1 modulates metabolic reprogramming to affect 5-FU resistance and cell pyroptosis in colorectal cancer

Background

Nanocarrier delivery of small interfering RNAs (siRNAs) to silence cancer-associated genes is a promising method for cancer treatment. Here, we explored the role and mechanisms of PLAG NPs-delivered si-Notch1 in colorectal cancer (CRC).

Results

High Notch1 expression was observed in both sensitive and resistant CRC tissues and cells. Notch1 silencing repressed proliferation and facilitates apoptosis of resistant CRC cells, and suppressed glycolysis and promoted pyroptosis in resistant CRC cells. Notch1 directly interacts with PCAF. Notch1 knockdown’s suppressive effect on glycolysis was reversed by overexpression of PCAF. Moreover, a nanocarrier called PLAG NPs was built with a higher delivery efficiency compared with lipo2000. Si-Notch1 delivered by PLAG NPs efficiently overcame the CRC cells’ 5-FU resistance and facilitated pyroptosis in a CRC mouse model.

Conclusions

PLAG NPs carrying si-Notch1 had a great advantage in the extension of half-life circulation and targeting ability, providing a theoretical foundation for precise clinical treatment of CRC.

Self-sustaining long-term 3D epithelioid cultures reveal drivers of clonal expansion in esophageal epithelium

Aging epithelia are colonized by somatic mutations, which are subjected to selection influenced by intrinsic and extrinsic factors. The lack of suitable culture systems has slowed the study of this and other long-term biological processes. Here, we describe epithelioids, a facile, cost-effective method of culturing multiple mouse and human epithelia. Esophageal epithelioids self-maintain without passaging for at least 1 year, maintaining a three-dimensional structure with proliferative basal cells that differentiate into suprabasal cells, which eventually shed and retain genomic stability. Live imaging over 5 months showed that epithelioids replicate in vivo cell dynamics. Epithelioids support genetic manipulation and enable the study of mutant cell competition and selection in three-dimensional epithelia, and show how anti-cancer treatments modulate competition between transformed and wild-type cells. Finally, a targeted CRISPR-Cas9 screen shows that epithelioids recapitulate mutant gene selection in aging human esophagus and identifies additional drivers of clonal expansion, resolving the genetic networks underpinning competitive fitness.

Capivasertib reverses chemotherapy-induced esophageal cancer resistance via inhibiting Akt-associated Mcl-1 upregulation

The development of resistance to chemotherapy in esophageal cancer represents a significant challenge in cancer treatment. Therefore, our study aimed to identify effective therapeutic strategies by examining the molecules involved in this chemoresistance. We consistently observed an increase in the expression of Mcl-1 in cells exposed to both short and long-term treatment with cisplatin, a drug commonly used in esophageal cancer therapy. Functional analysis showed that Mcl-1 regulates esophageal cancer cell response to cisplatin treatment. Notably, this upregulation of Mcl-1 was not dependent on eukaryotic initiation factor 4E (eIF4E). Instead, it was associated with increased stability due to the activation of Akt. Capivasertib, a potent pan-Akt kinase drug, significantly decreased Mcl-1 level via inhibiting Akt signaling pathway in chemo-resistant cells. In addition, capivasertib not only decreased the viability of chemo-resistant esophageal cancer cells but also synergistically enhanced the effects of cisplatin. In multiple mouse models, representing both chemo-resistant and chemo-sensitive esophageal cancer, capivasertib administered at non-toxic doses demonstrated remarkable efficacy. It significantly extended the overall survival of the mice. Our research underscores the pivotal role of Akt-associated Mcl-1 upregulation in the development of chemo-resistance in esophageal cancer cells. Furthermore, it highlights the potential of capivasertib to reverse this resistance mechanism.

Novel FOXM1 inhibitor STL001 sensitizes human cancers to a broad-spectrum of cancer therapies

Forkhead box protein M1 (FOXM1) is often overexpressed in human cancers and strongly associated with therapy resistance and less good patient survival. The chemotherapy options for patients with the most aggressive types of solid cancers remain very limited because of the acquired drug resistance, making the therapy less effective. NPM1 mutation through the inactivation of FOXM1 via FOXM1 relocalization to the cytoplasm confers more favorable treatment outcomes for AML patients, confirming FOXM1 as a crucial target to overcome drug resistance. Pharmacological inhibition of FOXM1 could be a promising approach to sensitize therapy-resistant cancers. Here, we explore a novel FOXM1 inhibitor STL001, a first-generation modification drug of our previously reported FOXM1 inhibitor STL427944. STL001 preserves the mode of action of the STL427944; however, STL001 is up to 50 times more efficient in reducing FOXM1 activity in a variety of solid cancers. The most conventional cancer therapies studied here induce FOXM1 overexpression in solid cancers. The therapy-induced FOXM1 overexpression may explain the failure or reduced efficacy of these drugs in cancer patients. Interestingly, STL001 increased the sensitivity of cancer cells to conventional cancer therapies by suppressing both the high-endogenous and drug-induced FOXM1. Notably, STL001 does not provide further sensitization to FOXM1-KD cancer cells, suggesting that the sensitization effect is conveyed specifically through FOXM1 suppression. RNA-seq and gene set enrichment studies revealed prominent suppression of FOXM1-dependent pathways and gene ontologies. Also, gene regulation by STL001 showed extensive overlap with FOXM1-KD, suggesting a high selectivity of STL001 toward the FOXM1 regulatory network. A completely new activity of FOXM1, mediated through steroid/cholesterol biosynthetic process and protein secretion in cancer cells was also detected. Collectively, STL001 offers intriguing translational opportunities as combination therapies targeting FOXM1 activity in a variety of human cancers driven by FOXM1.

Drug resistance‑related gene targets and molecular mechanisms in the A2780/Taxol‑resistant epithelial ovarian cancer cell line

Epithelial ovarian cancer (EOC) is a fatal gynecological malignant tumor with a low 5-year survival rate. The use of the first-line chemotherapeutic drug, paclitaxel, for the treatment of EOC is associated with resistance, often leading to treatment failure. The present study investigated the gene targets in an A2780 paclitaxel-resistant EOC cell line (A2780/Taxol), and the potential underlying mechanisms using transcriptome sequencing technology and bioinformatics analysis. The transcriptome of the A2780/Taxol cell line was sequenced, and 498 differentially expressed genes were obtained contained in the Gene Expression Omnibus dataset. Further bioinformatics analysis revealed that matrix metalloproteinase 1 (MMP1), zyxin (ZYX) and Unc-5 netrin receptor C (UNC5C) may be gene targets related to paclitaxel resistance. Moreover, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis indicated that a potential mechanism associated with paclitaxel resistance was related to cell migration. Furthermore, the expression levels of MMP1, ZYX and UNC5C were verified using western blotting, immunofluorescence and immunohistochemistry in vitro. The results revealed that the expression levels of MMP1 and ZYX were significantly increased in A2780/Taxol cells, while UNC5C expression was significantly decreased, which was consistent with the results of the transcriptome sequencing. The present study demonstrated that MMP1, ZYX and UNC5C may be the gene targets associated with paclitaxel resistance in EOC. These genes have potential to be used as molecular markers for EOC drug therapy, targeted elimination of drug resistance, and evaluation of treatment efficacy and patient prognosis.

[WITHDRAWN] Novel FOXM1 inhibitor STL001 sensitizes human cancers to a broad-spectrum of cancer therapies

The full text of this preprint has been withdrawn by the authors while they make corrections to the work. Therefore, the authors do not wish this work to be cited as a reference. Questions should be directed to the corresponding author.

[WITHDRAWN] Novel FOXM1 inhibitor STL001 sensitizes human cancers to a broad-spectrum of cancer therapies

The full text of this preprint has been withdrawn by the authors while they make corrections to the work. Therefore, the authors do not wish this work to be cited as a reference. Questions should be directed to the corresponding author.

Molecular mechanism underlying epithelial-mesenchymal transformation and cisplatin resistance in esophageal squamous cell carcinoma

Esophageal cancer (EC) occupies the seventh spot of the most prevalent malignancy cancer ailments worldwide and the sixth leading cause of cancer-related death. Esophageal squamous cell carcinoma (ESCC) is also the most predominant histological subtype of EC, and cisplatin (DDP) is commonly used as a first-line chemotherapeutic drug for the late advanced stages of the disease. However, the emergence of drug resistance during clinical treatment possesses a significant challenge to the therapeutic success and patient outcomes. Collectively, the epithelial-mesenchymal transformation (EMT) is a process in which transcription factors are induced to regulate the expression of epithelial and stromal markers to promote the differentiation of epithelial cells into stromal cells. Recent studies have demonstrated a close association between EMT and chemotherapy resistance in tumor cells, with concrete evidence of reciprocal reinforcement. Therefore, in this review, we elucidate the molecular mechanism underlying ESCC, shed light on the mechanisms driving DDP resistance, and provide insights into the intricate interplay between EMT and ESCC. We have aimed to provide some new hypotheses and perspectives that may address-inform future therapeutic strategies for ESCC treatment.

Lipid-hybrid cell-derived biomimetic functional materials: A state-of-the-art multifunctional weapon against tumors

Tumors are among the leading causes of death worldwide. Cell-derived biomimetic functional materials have shown great promise in the treatment of tumors. These materials are derived from cell membranes, extracellular vesicles and bacterial outer membrane vesicles and may evade immune recognition, improve drug targeting and activate antitumor immunity. However, their use is limited owing to their low drug-loading capacity and complex preparation methods. Liposomes are artificial bionic membranes that have high drug-loading capacity and can be prepared and modified easily. Although they can overcome the disadvantages of cell-derived biomimetic functional materials, they lack natural active targeting ability. Lipids can be hybridized with cell membranes, extracellular vesicles or bacterial outer membrane vesicles to form lipid-hybrid cell-derived biomimetic functional materials. These materials negate the disadvantages of both liposomes and cell-derived components and represent a promising delivery platform in the treatment of tumors. This review focuses on the design strategies, applications and mechanisms of action of lipid-hybrid cell-derived biomimetic functional materials and summarizes the prospects of their further development and the challenges associated with it.

Resveratrol reverses drug resistance of esophageal cancer cell line Eca109/DDP via regulating ferroptosis

BACKGROUND

Resveratrol not only has anti-tumor effects, but also can enhance the chemosensitivity of tumor cells to a variety of chemotherapeutic agents. However, its effect on cisplatin sensitivity of drug-resistant esophageal cancer cells remains unclear.

AIM

To investigate whether resveratrol reverses the drug resistance of esophageal cancer Eca109/DDP cells and to explore the potential mechanism involved from the perspective of ferroptosis.

METHODS

The optimal treatment time and concentration of resveratrol and cisplatin were determined by MTT assay. Cell proliferation and the intracellular levels of malon-dialdehyde (MDA), glutathione (GSH), reactive oxygen species (ROS), and ferrous iron were detected. The protein expression of the ferroptosis-related molecules acyl coenzyme A synthetase long chain family member 4 (ACSL4), ferritin heavy chain (FTH), glutathione peroxidase 4 (GPX4), and tumor protein 53 (P53) was detected by Western blot assay.

RESULTS

MTT assay showed that compared with cisplatin alone, resveratrol combined with cisplatin significantly inhibited the growth of Eca109/DDP cells (P < 0.05). The combination of resveratrol and cisplatin not only reduced the number of colonies formed (P < 0.05), but also increased the levels of ferrous iron, MDA, and ROS (P < 0.05) and decreased the level of GSH (P < 0.05) in Eca109/DDP cells. The inhibitory effect of resveratrol on Eca109/DDP cell proliferation was partially reversed by ferrostatin-1 (Fer-1) and deferoxamine (DFO) (P < 0.05). Western blot analysis showed that compared with other groups, the protein expression of FTH and GPX4 in the resveratrol and cisplatin combination group was significantly decreased (P < 0.05), and the protein expression of ACSL4 and P53 was significantly increased (P < 0.05).

CONCLUSION

Resveratrol can inhibit cell proliferation and reverse cisplatin resistance by regulating ferroptosis in Eca109/DDP cells.

Increased Expression of the Pathological O-glycosylated Form of Oncofetal Fibronectin in the Multidrug Resistance Phenotype of Cancer Cells

Changes in protein glycosylation are a hallmark of transformed cells and modulate numerous phenomena associated with cancer progression, such as the acquisition of multidrug resistance (MDR) phenotype. Different families of glycosyltransferases and their products have already been described as possible modulators of the MDR phenotype. Among the glycosyltransferases intensively studied in cancer research, UDP-N-acetyl-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase-6 (pp-GalNAc-T6), which is widely expressed in many organs and tissues, stands out. Its influence in several events associated with kidney, oral, pancreatic, renal, lung, gastric and breast cancer progression has already been described. However, its participation in the MDR phenotype has never been studied. Here, we demonstrate that human breast adenocarcinoma MCF-7 MDR cell lines, generated by chronic exposure to doxorubicin, in addition to exhibiting increased expression of proteins belonging to the ABC superfamily (ABCC1 and ABCG2), and anti-apoptotic proteins (Blcl-2 and Bcl-xL), also present high expression of pp-GalNAc-T6, the enzyme currently proposed as the main responsible for the biosynthesis of oncofetal fibronectin (onf-FN), a major extracellular matrix component expressed by cancer cells and embryonic tissues, but absent in healthy cells. Our results show that onf-FN, which is generated by the addition of a GalNAc unit at a specific threonine residue inside the type III homology connective segment (IIICS) domain of FN, is strongly upregulated during the acquisition of the MDR phenotype. Also, the silencing of pp-GalNAc-T6, not only compromises the expression of the oncofetal glycoprotein, but also made the MDR cells more sensitive to all anticancer drugs tested, partially reversing the MDR phenotype. Taken together, our results demonstrate for the first time the upregulation of the O-glycosylated oncofetal fibronectin, as well as the direct participation of pp-GalNAc-T6 during the acquisition of a MDR phenotype in a breast cancer model, giving credence to the hypothesis that in transformed cells, glycosyltransferases and/or their products, such as unusual extracellular matrix glycoproteins can be used as potential therapeutic targets for the treatment of cancer.

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 30-150 nm 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.

PMN-MDSCs modulated by CCL20 from cancer cells promoted breast cancer cell stemness through CXCL2-CXCR2 pathway

Our previous studies have showed that C-C motif chemokine ligand 20 (CCL20) advanced tumor progression and enhanced the chemoresistance of cancer cells by positively regulating breast cancer stem cell (BCSC) self-renewal. However, it is unclear whether CCL20 affects breast cancer progression by remodeling the tumor microenvironment (TME). Here, we observed that polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) were remarkably enriched in TME of CCL20-overexpressing cancer cell orthotopic allograft tumors. Mechanistically, CCL20 activated the differentiation of granulocyte-monocyte progenitors (GMPs) via its receptor C-C motif chemokine receptor 6 (CCR6) leading to the PMN-MDSC expansion. PMN-MDSCs from CCL20-overexpressing cell orthotopic allograft tumors (CCL20-modulated PMN-MDSCs) secreted amounts of C-X-C motif chemokine ligand 2 (CXCL2) and increased ALDH+ BCSCs via activating CXCR2/NOTCH1/HEY1 signaling pathway. Furthermore, C-X-C motif chemokine receptor 2 (CXCR2) antagonist SB225002 enhanced the docetaxel (DTX) effects on tumor growth by decreasing BCSCs in CCL20high-expressing tumors. These findings elucidated how CCL20 modulated the TME to promote cancer development, indicating a new therapeutic strategy by interfering with the interaction between PMN-MDSCs and BCSCs in breast cancer, especially in CCL20high-expressing breast cancer.

Cellular and molecular basis of therapeutic approaches to breast cancer

In recent decades, there has been a significant amount of research into breast cancer, with some important breakthroughs in the treatment of both primary and metastatic breast cancers. It's a well-known fact that treating breast cancer is still a challenging endeavour even though physicians have a fantastic toolset of the latest treatment options at their disposal. Due to limitations of current clinical treatment options, traditional chemotherapeutic drugs, and surgical options are still required to address this condition. In recent years, there have been several developments resulting in a wide range of treatment options. This review article discusses the cellular and molecular foundation of chemotherapeutic drugs, endocrine system-based treatments, biological therapies, gene therapy, and innovative techniques for treating breast cancer.

Cancer organoid applications to investigate chemotherapy resistance

In clinical practice, a large proportion of cancer patients receive chemotherapy, yet tumors persist or acquire resistance; removing this obstacle could help to lower the number of cancer-related fatalities. All areas of cancer research are increasingly using organoid technology, a culture technique that simulates the in vivo environment in vitro, especially in the quickly developing fields of anticancer drug resistance, drug-tolerant persisters, and drug screening. This review provides an overview of organoid technology, the use of organoids in the field of anticancer drug resistance research, their relevance to clinical information and clinical trials, and approaches to automation and high throughput.

Natural Products-Based Nanoformulations: A New Approach Targeting CSCs to Cancer Therapy

Cancer stem cells (CSCs) lead to the occurrence and progression of cancer due to their strong tumorigenic, self-renewal, and multidirectional differentiation abilities. Existing cancer treatment methods cannot effectively kill or inhibit CSCs but instead enrich them and produce stronger proliferation, invasion, and metastasis capabilities, resulting in cancer recurrence and treatment resistance, which has become a difficult problem in clinical treatment. Therefore, targeting CSCs may be the most promising approach for comprehensive cancer therapy in the future. A variety of natural products (NP) have significant antitumor effects and have been identified to target and inhibit CSCs. However, pharmacokinetic defects and off-target effects have greatly hindered their clinical translation. NP-based nanoformulations (NPNs) have tremendous potential to overcome the disadvantages of NP against CSCs through site-specific delivery and by improving their pharmacokinetic parameters. In this review, we summarize the recent progress of NPNs targeting CSCs in cancer therapy, looking forward to transforming preclinical research results into clinical applications and bringing new prospects for cancer treatment.

CNTN-1 Upregulation Induced by Low-Dose Cisplatin Promotes Malignant Progression of Lung Adenocarcinoma Cells via Activation of Epithelial-Mesenchymal Transition

Tumor metastasis and invasion are the main impediments to lung adenocarcinoma successful treatment. Previous studies demonstrate that chemotherapeutic agents can elevate the malignancy of cancer cells other than their therapeutic effects. In this study, the effects of transient low-dose cisplatin treatment on the malignant development of lung adenocarcinoma cells (A549) were detected, and the underlying epigenetic mechanisms were investigated. The findings showed that A549 cells exhibited epithelial-mesenchymal transition (EMT)-like phenotype along with malignant progression under the transient low-dose cisplatin treatment. Meanwhile, low-dose cisplatin was found to induce contactin-1 (CNTN-1) upregulation in A549 cells. Subsequently, we found that further overexpressing CNTN-1 in A549 cells obviously activated the EMT process in vitro and in vivo, and caused malignant development of A549 cells in vitro. Taken together, we conclude that low-dose cisplatin can activate the EMT process and resulting malignant progression through upregulating CNTN-1 in A549 cells. The findings provided new evidence that a low concentration of chemotherapeutic agents could facilitate the malignancy of carcinoma cells via activating the EMT process other than their therapeutic effects.

Exosomal MiRNAs in Osteosarcoma: Biogenesis and Biological Functions

MiRNAs are a group of non-coding RNA molecules that function in mRNA translational inhibition via base-pairing with complementary sequences in target mRNA. In oncology, miRNAs have raised great attention due to their aberrant expression and pivotal roles in the pathogenesis of multiple malignancies including osteosarcoma. MiRNAs can be transported by exosome, the nano-extracellular vesicle with a diameter of 30–150 nm. Recently, a growing number of studies have demonstrated that exosomal miRNAs play a critical role in tumor initiation and progression, by exerting multiple biological functions including metastasis, angiogenesis, drug resistance and immunosuppression. In this review, we aim to depict the biogenesis of exosomal miRNAs and summarize the potential diagnostic and therapeutic functions of exosomal miRNAs in osteosarcoma.