The epithelial to mesenchymal transition (EMT) and cancer stem cells: implication for treatment resistance in pancreatic cancer

Smad4 regulates TGF-β1-mediated hedgehog activation to promote epithelial-to-mesenchymal transition in pancreatic cancer cells by suppressing Gli1 activity

Pancreatic cancer (PC) is an aggressive and metastatic gastrointestinal tumor with a poor prognosis. Persistent activation of the TGF-β/Smad signaling induces PC cell (PCC) invasion and infiltration via epithelial-to-mesenchymal transition (EMT). Hedgehog signaling is a crucial pathway for the development of PC via the transcription factors Gli1/2/3. This study aimed to investigate the underlying molecular mechanisms of action of hedgehog activation in TGF-β1-triggered EMT in PCCs (PANC-1 and BxPc-3). In addition, overexpression and shRNA techniques were used to evaluate the role of Smad4 in TGF-β1-treated PCCs. Our data showed that TGF-β1 promoted PCC invasion and infiltration via Smad2/3-dependent EMT. Hedgehog-Gli signaling axis in PCCs was activated upon TGF-β1 stimulation. Inhibition of hedgehog with cyclopamine effectively antagonized TGF-β1-induced EMT, thereby suggesting that the hedgehog signaling may act as a downstream cascade signaling of TGF-β1. As a key protein that assists the nuclear translocation of Smad2/3, Smad4 was highly expressed in PANC-1 cells, but not in BxPc-3 cells. Conversely, Gli1 expression was low in PANC-1 cells, but high in BxPc-3 cells. Furthermore, knockdown of Smad4 in PANC-1 cells by shRNA inhibited TGF-β1-mediated EMT and collagen deposition. Overexpression of Smad4 did not affect TGF-β1-mediated EMT due to the lack of significant increase in nuclear expression of Smad4. Importantly, Gli1 activity was upregulated by Smad4 knockdown in PANC-1 cells and downregulated by Smad4 overexpression in BxPc-3 cells, indicating that Gli1 may be a negative target protein downstream of Smad4. Thus, Smad4 regulates TGF-β1-mediated hedgehog activation to promote EMT in PCCs by suppressing Gli1 activity.

Modulating PCGF4/BMI1 Stability Is an Efficient Metastasis-Regulatory Strategy Used by Distinct Subtypes of Cancer-Associated Fibroblasts in Intrahepatic Cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC) is a highly malignant neoplasm prone to metastasis. Whether cancer-associated fibroblasts (CAFs) affect the metastasis of ICC is unclear. Herein, ICC patient-derived CAF lines and related cancerous cell lines were established and the effects of CAFs on the tumor progressive properties of the ICC cancerous cells were analyzed. CAFs could be classified into cancer-restraining or cancer-promoting categories based on distinct tumorigenic effects. The RNA-sequencing analyses of ICC cancerous cell lines identified polycomb group ring finger 4 (PCGF4; alias BMI1) as a potential metastasis regulator. The changes of PCGF4 levels in ICC cells mirrored the restraining or promoting effects of CAFs on ICC migration. Immunohistochemical analyses on the ICC tissue microarrays indicated that PCGF4 was negatively correlated with overall survival of ICC. The promoting effects of PCGF4 on cell migration, drug resistance activity, and stemness properties were confirmed. Mechanistically, cancer-restraining CAFs triggered the proteasome-dependent degradation of PCGF4, whereas cancer-promoting CAFs enhanced the stability of PCGF4 via activating the IL-6/phosphorylated STAT3 pathway. In summary, the current data identified the role of CAFs in ICC metastasis and revealed a new mechanism of the CAFs on ICC progression in which PCGF4 acted as the key effector by both categories of CAFs. These findings shed light on developing comprehensive therapeutic strategies for ICC.

Progress of single-cell RNA sequencing combined with spatial transcriptomics in tumour microenvironment and treatment of pancreatic cancer

In recent years, single-cell analyses have revealed the heterogeneity of the tumour microenvironment (TME) at the genomic, transcriptomic, and proteomic levels, further improving our understanding of the mechanisms of tumour development. Single-cell RNA sequencing (scRNA-seq) technology allow analysis of the transcriptome at the single-cell level and have unprecedented potential for exploration of the characteristics involved in tumour development and progression. These techniques allow analysis of transcript sequences at higher resolution, thereby increasing our understanding of the diversity of cells found in the tumour microenvironment and how these cells interact in complex tumour tissue. Although scRNA-seq has emerged as an important tool for studying the tumour microenvironment in recent years, it cannot be used to analyse spatial information for cells. In this regard, spatial transcriptomics (ST) approaches allow researchers to understand the functions of individual cells in complex multicellular organisms by understanding their physical location in tissue sections. In particular, in related research on tumour heterogeneity, ST is an excellent complementary approach to scRNA-seq, constituting a new method for further exploration of tumour heterogeneity, and this approach can also provide unprecedented insight into the development of treatments for pancreatic cancer (PC). In this review, based on the methods of scRNA-seq and ST analyses, research progress on the tumour microenvironment and treatment of pancreatic cancer is further explained.

ZNF263 cooperates with ZNF31 to promote the drug resistance and EMT of pancreatic cancer through transactivating RNF126

The poor prognosis of pancreatic ductal adenocarcinoma (PDAC) is attribute to the aggressive local invasion, distant metastasis and drug resistance of PDAC patients, which was strongly accelerated by epithelial-mesenchymal transition (EMT). In current study, we systematically investigate the role of ZNF263/RNF126 axis in the initiation of EMT in PDAC in vitro and vivo. ZNF263 is firstly identified as a novel transactivation factor of RNF126. Both ZNF263 and RNF126 were overexpressed in PDAC tissues, which were associated with multiple advanced clinical stages and poor prognosis of PDAC patients. ZNF263 overexpression promoted cell proliferation, drug resistance and EMT in vitro via activating RNF126 following by the upregulation of Cyclin D1, N-cad, and MMP9, and the downregulation of E-cad, p21, and p27. ZNF263 silencing contributed to the opposite phenotype. Mechanistically, ZNF263 transactivated RNF126 via binding to its promoter. Further investigations revealed that ZNF263 interacted with ZNF31 to coregulate the transcription of RNF126, which in turn promoted ubiquitination-mediated degradation of PTEN. The downregulation of PTEN activated AKT/Cyclin D1 and AKT/GSK-3β/β-catenin signaling, thereby promoting the malignant phenotype of PDAC. Finally, the coordination of ZNF263 and RNF126 promotes subcutaneous tumor size and distant liver metastasis in vivo. ZNF263, as an oncogene, promotes proliferation, drug resistance and EMT of PDAC through transactivating RNF126.

Screening approach by a combination of computational and in vitro experiments: identification of fluvastatin sodium as a potential SIRT2 inhibitor

BACKGROUND

Sirtuins (SIRTs) are NAD+-dependent deacetylases that play various roles in numerous pathophysiological processes, holding promise as therapeutic targets worthy of further investigation. Among them, the SIRT2 subtype is closely associated with tumorigenesis and malignancies. Dysregulation of SIRT2 activation can regulate the expression levels of related genes in cancer cells, leading to tumor occurrence and metastasis.

METHODS

In this study, we used computer simulations to screen for novel SIRT2 inhibitors from the FDA database, based on which 10 compounds with high docking scores and good interactions were selected for in vitro anti-pancreatic cancer metastasis testing and enzyme binding inhibition experiments. The results showed that fluvastatin sodium may possess inhibitory activity against SIRT2. Subsequently, fluvastatin sodium was subjected to molecular docking experiments with various SIRT isoforms, and the combined results from Western blotting experiments indicated its potential as a SIRT2 inhibitor. Next, molecular docking, molecular dynamics (MD) simulations, and binding free energy calculations were performed, revealing the binding mode of fluvastatin sodium at the SIRT2 active site, further validating the stability and interaction of the ligand-protein complex under physiological conditions.

RESULTS

Overall, this study provides a systematic virtual screening workflow for the discovery of SIRT2 activity inhibitors, identifies the potential inhibitory effect of fluvastatin sodium as a lead compound on SIRT2, and opens up a new direction for developing highly active and selectively targeted SIRT2 inhibitors.

The bacterial metabolite, lithocholic acid, has antineoplastic effects in pancreatic adenocarcinoma

Lithocholic acid (LCA) is a secondary bile acid. LCA enters the circulation after bacterial synthesis in the gastrointestinal tract, reaches distantly located cancer cells, and influences their behavior. LCA was considered carcinogenic, but recent studies demonstrated that LCA has antitumor effects. We assessed the possible role of LCA in pancreatic adenocarcinoma. At the serum reference concentration, LCA induced a multi-pronged antineoplastic program in pancreatic adenocarcinoma cells. LCA inhibited cancer cell proliferation and induced mesenchymal-to-epithelial (MET) transition that reduced cell invasion capacity. LCA induced oxidative/nitrosative stress by decreasing the expression of nuclear factor, erythroid 2-like 2 (NRF2) and inducing inducible nitric oxide synthase (iNOS). The oxidative/nitrosative stress increased protein nitration and lipid peroxidation. Suppression of oxidative stress by glutathione (GSH) or pegylated catalase (pegCAT) blunted LCA-induced MET. Antioxidant genes were overexpressed in pancreatic adenocarcinoma and decreased antioxidant levels correlated with better survival of pancreatic adenocarcinoma patients. Furthermore, LCA treatment decreased the proportions of cancer stem cells. Finally, LCA induced total and ATP-linked mitochondrial oxidation and fatty acid oxidation. LCA exerted effects through the farnesoid X receptor (FXR), vitamin D receptor (VDR), and constitutive androstane receptor (CAR). LCA did not interfere with cytostatic agents used in the chemotherapy of pancreatic adenocarcinoma. Taken together, LCA is a non-toxic compound and has antineoplastic effects in pancreatic adenocarcinoma.

E3 ubiquitin ligase UBR5 promotes gemcitabine resistance in pancreatic cancer by inducing O-GlcNAcylation-mediated EMT via destabilization of OGA

Pancreatic cancer (PC) is among the deadliest malignancies, with an extremely poor diagnosis and prognosis. Gemcitabine (GEM) remains the first-line drug for treating PC; however, only a small percentage of patients benefit from current immunotherapies or targeted therapies. Resistance to GEM is prevalent and affects long-term survival. We found that ubiquitin-protein ligase E3 module N-recognition 5 (UBR5) is a therapeutic target against GEM resistance. UBR5 was markedly upregulated in clinical GEM-resistant PC samples and GEM-resistant PC cells. UBR5 knockdown markedly increased GEM sensitivity in GEM-resistant PC cell lines. UBR5-mediated GEM resistance was accompanied by activation of epithelial-mesenchymal transition (EMT) and could be mitigated by inhibiting EMT. Further analysis revealed that UBR5 promoted GEM resistance in PC cells by enhancing O-GlcNAcylation-mediated EMT. In addition, UBR5 knockdown resulted in increased O-GlcNAase (OGA) levels, an essential negatively regulated enzyme in the O-GlcNAcylation process. We identified a negative association between OGA and UBR5 levels, which further supported the hypothesis that O-GlcNAcylation-mediated GEM resistance induced by UBR5 is OGA-dependent in PC cells. Mechanistic studies revealed that UBR5 acts as an E3 ubiquitin ligase of OGA and regulates O-GlcNAcylation by binding and modulating OGA, facilitating its degradation and ubiquitination. Additionally, high-throughput compound library screening using three-dimensional protein structure analysis and drug screening identified a Food and Drug Administration drug, Y-39983 dihydrochloride, as a potent GEM sensitiser and UBR5 inhibitor. The combination of Y-39983 dihydrochloride and GEM attenuated tumour growth in a mouse xenograft tumour model. Collectively, these data demonstrated that UBR5 plays a pivotal role in the sensitisation of PC to GEM and provides a potential therapeutic strategy to overcome GEM resistance.

The nanobody targeting PD-L1 and CXCR4 counteracts pancreatic stellate cell-mediated tumour progression by disrupting tumour microenvironment

Pancreatic ductal adenocarcinoma (PDAC) is the most lethal malignancy worldwide owing to its complex tumour microenvironment and dense physical barriers. Stromal-derived factor-1 (SDF-1), which is abundantly secreted by tumour stromal cells, plays a pivotal role in promoting PDAC growth and metastasis. In this study, we investigated the impact and molecular mechanisms of the anti-PD-L1&CXCR4 bispecific nanobody on the TME and their consequent interference with PDAC progression. We found that blocking the SDF-1/CXCR4 signalling pathway delayed the epithelial-mesenchymal transition in pancreatic cancer cells. Anti-PD-L1&CXCR4 bispecific nanobody effectively suppress the secretion of SDF-1 by pancreatic stellate cells and downregulate the expression of smooth muscle actin alpha(α-SMA), thereby preventing the activation of cancer-associated fibroblasts by downregulating the PI3K/AKT signaling pathway. This improves the pancreatic tumour microenvironment, favouring the infiltration of T cells into the tumour tissue. In conclusion, our results suggest that the anti-PD-L1&CXCR4 bispecific nanobody exerts an antitumor immune response by changing the pancreatic tumour microenvironment. Hence, the anti-PD-L1&CXCR4 bispecific nanobody is a potential candidate for pancreatic cancer treatment.

microRNA-141-3p Suppressed the Progression of the Clear Cell Renal Cell Carcinoma by Targeting Transforming Growth Factor Beta 2 Gene Expression

Clear cell renal cell carcinoma (ccRCC) is a malignant tumor of kidney epithelial cells, one of the most common tumors in the world. Transforming growth factor beta (TGFβ)1 is a crucial factor that induces epithelial-mesenchymal transition (EMT) in cancer cells. microRNA-141-3p (miR-141-3p) is a microRNA that is considered a tumor suppressor. However, the role and mechanism of miR-141-3p in TGFβ1-induced ccRCC cells are not fully understood. This study investigated the roles of miR-141-3p and its target gene in regulating EMT in ccRCC development. 786-0 and Caki-1cells were treated with TGFβ1 to induce EMT. The levels of miR-141-3p and TGFβ2 were determined by quantitative real-time polymerase chain reaction and Western blotting. The progression of EMT was evaluated by E-cadherin detection by immunofluorescence, and E-cadherin, N-cadherin, and vimentin detection by Western blotting. Furthermore, migration and invasion capacities were assessed using a Transwell system. The direct binding of miR-141-3p with the target gene TGFβ2 was confirmed by dual luciferase reporter gene assay. Results indicated that TGFβ1 treatment decreased the protein abundance of E-cadherin while increasing the protein expression of N-cadherin and vimentin, indicating TGFβ1-induced EMT was constructed successfully. Moreover, TGFβ1 treatment repressed the expression of miR-141-3p. miR-141-3p mimics reversed the effect of TGFβ1 on the migration, invasion, and expression of E-cadherin, N-cadherin, and vimentin. The miR-141-3p directly binds with the 3' untranslated region of TGFβ2 mRNA and suppresses its expression. Furthermore, TGFβ2 overexpression abrogated the above changes regulated by miR-141-3p mimics. Taken together, miR-141-3p inhibited TGFβ1-induced EMT by suppressing the migration and invasion of ccRCC cells via directly targeting TGFβ2 gene expression.

Tumor microenvironment of cancer stem cells: Perspectives on cancer stem cell targeting

There are few tumor cell subpopulations with stem cell characteristics in tumor tissue, defined as cancer stem cells (CSCs) or cancer stem-like cells (CSLCs), which can reconstruct neoplasms with malignant biological behaviors such as invasiveness via self-renewal and unlimited generation. The microenvironment that CSCs depend on consists of various cellular components and corresponding medium components. Among these factors existing at a variety of levels and forms, cytokine networks and numerous signal pathways play an important role in signaling transduction. These factors promote or maintain cancer cell stemness, and participate in cancer recurrence, metastasis, and resistance. This review aims to summarize the recent molecular data concerning the multilayered relationship between CSCs and CSC-favorable microenvironments. We also discuss the therapeutic implications of targeting this synergistic interplay, hoping to give an insight into targeting cancer cell stemness for tumor therapy and prognosis.

Nuclear MAST4 Suppresses FOXO3 through Interaction with AKT3 and Induces Chemoresistance in Pancreatic Ductal Carcinoma

Pancreatic ductal adenocarcinoma (PDAC) is highly malignant, with a 5-year survival rate of less than 10%. Furthermore, the acquisition of anticancer drug resistance makes PDAC treatment difficult. We established MIA-GEM cells, a PDAC cell line resistant to gemcitabine (GEM), a first-line anticancer drug, using the human PDAC cell line-MIA-PaCa-2. Microtubule-associated serine/threonine kinase-4 (MAST4) expression was increased in MIA-GEM cells compared with the parent cell line. Through inhibitor screening, dysregulated AKT signaling was identified in MIA-GEM cells with overexpression of AKT3. MAST4 knockdown effectively suppressed AKT3 overexpression, and both MAST4 and AKT3 translocation into the nucleus, phosphorylating forkhead box O3a (FOXO3) in MIA-GEM cells. Modulating FOXO3 target gene expression in these cells inhibited apoptosis while promoting stemness and proliferation. Notably, nuclear MAST4 demonstrated higher expression in GEM-resistant PDAC cases compared with that in the GEM-sensitive cases. Elevated MAST4 expression correlated with a poorer prognosis in PDAC. Consequently, nuclear MAST4 emerges as a potential marker for GEM resistance and poor prognosis, representing a novel therapeutic target for PDAC.

Chloroxine inhibits pancreatic cancer progression through targeted antagonization of the PI3K/AKT/mTOR signaling pathway

BACKGROUND

Patients with pancreatic cancer have a dismal prognosis due to tumor cell infiltration and metastasis. Many reports have documented that EMT and PI3K-AKT-mTOR axis control pancreatic cancer cell infiltration and metastasis. Chloroxine is an artificially synthesized antibacterial compound that demonstrated anti-pancreatic cancer effects in our previous drug-screening trial. We have explored the impact of chloroxine on pancreatic cancer growth, infiltration, migration, and apoptosis.

METHODS

The proliferation of pancreatic cancer cell lines (PCCs) treated with chloroxine was assessed through real-time cell analysis (RTCA), colony formation assay, CCK-8 assay, as well as immunofluorescence. Chloroxine effects on the infiltrative and migratory capacities of PCCs were assessed via Transwell invasion and scratch experiments. To assess the contents of EMT- and apoptosis-associated proteins in tumor cells, we adopted Western immunoblotting as well as immunofluorescence assays, and flow cytometry to determine chloroxine effects on PCCs apoptosis. The in vivo chloroxine antineoplastic effects were explored in nude mice xenografts.

RESULTS

Chloroxine repressed pancreatic cancer cell growth, migration, and infiltration in vitro, as well as in vivo, and stimulated apoptosis of the PCCs. Chloroxine appeared to inhibit PCC growth by Ki67 downregulation; this targeted and inhibited aberrant stimulation of the PI3K-AKT-mTOR signaling cascade, triggered apoptosis in PCC via mitochondria-dependent apoptosis, and modulated the EMT to inhibit PCC infiltration and migration.

CONCLUSIONS

Chloroxine targeted and inhibited the PI3K-AKT-mTOR cascade to repress PCCs growth, migration, as well as invasion, and triggered cellular apoptosis. Therefore, chloroxine may constitute a potential antineoplastic drug for the treatment of pancreatic cancer.

Loss of Claudin-1 incurred by DNMT aberration promotes pancreatic cancer progression

Pancreatic cancer (PC) is one of the most malignant and deadly tumors of digestive system with complex etiology and pathogenesis. Dysregulations of oncogenes and tumor suppressors due to epigenetic modifications causally affect tumorogenesis; however the key tumor suppressors and their regulations in PC are only partially defined. In this study, we found that Claudin-1 (encoded by CLDN1 gene) was significantly suppressed in PC that correlated with a poor clinical prognosis. Claudin-1 knockdown enhanced PC cell proliferation, migration, and stemness. Pancreatic specific Cldn1 knockout in KPC (LSLKrasG12D/Pdx1-Cre/Trp53R172H+) and KC (LSLKrasG12D/Pdx1-Cre) mice reduced mouse survival, promoted acinar-to-ductal metaplasia (ADM) process, and accelerated the development of pancreatic intraepithelial neoplasia (PanIN) and PC. Further investigation revealed that Claudin-1 suppression was mainly caused by aberrant DNA methylatransferase 1 (DNMT1) and DNMT3A elevations and the resultant CLDN1 promoter hypermethylation, as a DNMT specific inhibitor SGI-1027 effectively reversed the Claudin-1 suppression and inhibited PC progression both in vitro and in vivo in a Claudin-1 preservation-dependent manner. Together, our data suggest that Claudin-1 functions as a tumor suppressor in PC and its epigenetic suppression due to DNMT aberrations is a crucial event that promotes PC development and progression.

LINC00909 up-regulates pluripotency factors and promotes cancer stemness and metastasis in pancreatic ductal adenocarcinoma by targeting SMAD4

BACKGROUND

Pancreatic cancer stem cells are crucial for tumorigenesis and cancer metastasis. Presently, long non-coding RNAs were found to be associated with Pancreatic Ductal Adenocarcinoma stemness characteristics but the underlying mechanism is largely known. Here, we aim to explore the function of LINC00909 in regulating pancreatic cancer stemness and cancer metastasis.

METHODS

The expression level and clinical characteristics of LINC00909 were verified in 80-paired normal pancreas and Pancreatic Ductal Adenocarcinoma tissues from Guangdong Provincial People's Hospital cohort by in situ hybridization. RNA sequencing of PANC-1 cells with empty vector or vector encoding LINC00909 was experimented for subsequent bioinformatics analysis. The effect of LINC00909 in cancer stemness and metastasis was examined by in vitro and in vivo experiments. The interaction between LINC00909 with SMAD4 and the pluripotency factors were studied.

RESULTS

LINC00909 was generally upregulated in pancreatic cancer tissues and was associated with inferior clinicopathologic features and outcome. Over-expression of LINC00909 enhanced the expression of pluripotency factors and cancer stem cells phenotype, while knock-down of LINC00909 decreased the expression of pluripotency factors and cancer stem cells phenotype. Moreover, LINC00909 inversely regulated SMAD4 expression, knock-down of SMAD4 rescued the effect of LINC00909-deletion inhibition on pluripotency factors and cancer stem cells phenotype. These indicated the effect of LINC00909 on pluripotency factors and CSC phenotype was dependent on SMAD4 and MAPK/JNK signaling pathway, another downstream pathway of SMAD4 was also activated by LINC00909. Specifically, LINC00909 was localized in the cytoplasm in pancreatic cancer cells and decreased the stability the SMAD4 mRNA. Finally, we found over-expression of LINC00909 not only accelerated tumor growth in subcutaneous mice models, but also facilitated tumorigenicity and spleen metastasis in orthotopic mice models.

CONCLUSION

We demonstrate LINC00909 inhibits SMAD4 expression at the post-transcriptional level, which up-regulates the expression of pluripotency factors and activates the MAPK/JNK signaling pathway, leading to enrichment of cancer stem cells and cancer metastasis in pancreatic cancer.

Exercise potentially prevents colorectal cancer liver metastases by suppressing tumor epithelial cell stemness via RPS4X downregulation

Background

Colorectal cancer (CRC) is the third most prevalent tumor globally. The liver is the most common site for CRC metastasis, and the involvement of the liver is a common cause of death in patients with late-stage CRC. Consequently, mitigating CRC liver metastasis (CRLM) is key to improving CRC prognosis and increasing survival. Exercise has been shown to be an effective method of improving the prognosis of many tumor types. However, the ability of exercise to inhibit CRLM is yet to be thoroughly investigated.

Methods

The GSE157600 and GSE97084 datasets were used for analysis. A pan-cancer dataset which was uniformly normalized was downloaded and analyzed from the UCSC database: TCGA, TARGET, GTEx (PANCAN, n = 19,131, G = 60,499). Several advanced bioinformatics analyses were conducted, including single-cell sequencing analysis, correlation algorithm, and prognostic screen. CRC tumor microarray (TMA) as well as cell/animal experiments are used to further validate the results of the analysis.

Results

The greatest variability was found in epithelial cells from the tumor group. RPS4X was generally upregulated in all types of CRC, while exercise downregulated RPS4X expression. A lowered expression of RPS4X may prolong tumor survival and reduce CRC metastasis. RPS4X and tumor stemness marker-CD44 were highly positively correlated and knockdown of RPS4X expression reduced tumor stemness both in vitro and in vivo.

Conclusion

RPS4X upregulation may enhance CRC stemness and increase the odds of metastasis. Exercise may reduce CRC metastasis through the regulation of RPS4X.

The role of histone H1.2 in pancreatic cancer metastasis and chemoresistance

AIMS

Pancreatic cancer (PC) is a highly metastatic malignant tumor of the digestive system. Drug resistance frequently occurs during cancer treatment process. This study aimed to explore the link between chemoresistance and tumor metastasis in PC and its possible molecular and cellular mechanisms.

METHODS

A Metastasis and Chemoresistance Signature (MCS) scoring system was built and validated based on metastasis- and chemoresistance-related genes using gene expression data of PC, and the model was applied to single-cell RNA sequencing data. The influence of linker histone H1.2 (H1-2) on PC was explored through in vitro and in vivo experiments including proliferation, invasion, migration, drug sensitivity, rescue experiments and immunohistochemistry, emphasizing its regulation with c-MYC signaling pathway.

RESULTS

A novel MCS scoring system accurately predicted PC patient survival and was linked to chemoresistance and epithelial-mesenchymal transition (EMT) in PC single-cell RNA sequencing data. H1-2 emerged as a significant prognostic factor, with its high expression indicating increased chemoresistance and EMT. This upregulation was mediated by c-MYC, which was also found to be highly expressed in PC tissues.

CONCLUSION

The MCS scoring system offers insights into PC chemoresistance and metastasis potential. Targeting H1-2 could enhance therapeutic strategies and improve PC patient outcomes.

Discovery of a potent and highly selective inhibitor of SIRT6 against pancreatic cancer metastasis in vivo

Pancreatic cancer, one of the most aggressive malignancies, has no effective treatment due to the lack of targets and drugs related to tumour metastasis. SIRT6 can promote the migration of pancreatic cancer and could be a potential target for antimetastasis of pancreatic cancer. However, highly selective and potency SIRT6 inhibitor that can be used in vivo is yet to be discovered. Here, we developed a novel SIRT6 allosteric inhibitor, compound 11e, with maximal inhibitory potency and an IC50 value of 0.98 ± 0.13 μmol/L. Moreover, compound 11e exhibited significant selectivity against other histone deacetylases (HADC1‒11 and SIRT1‒3) at concentrations up to 100 μmol/L. The allosteric site and the molecular mechanism of inhibition were extensively elucidated by cocrystal complex structure and dynamic structural analyses. Importantly, we confirmed the antimetastatic function of such inhibitors in four pancreatic cancer cell lines as well as in two mouse models of pancreatic cancer liver metastasis. To our knowledge, this is the first study to reveal the in vivo effects of SIRT6 inhibitors on liver metastatic pancreatic cancer. It not only provides a promising lead compound for subsequent inhibitor development targeting SIRT6 but also provides a potential approach to address the challenge of metastasis in pancreatic cancer.

Insights into lenvatinib resistance: mechanisms, potential biomarkers, and strategies to enhance sensitivity

Lenvatinib is a multitargeted tyrosine kinase inhibitor capable of promoting apoptosis, suppressing angiogenesis, inhibiting tumor cell proliferation, and modulating the immune response. In multiple cancer types, lenvatinib has presented manageable safety and is currently approved as an effective first-line therapy. However, with the gradual increase in lenvatinib application, the inevitable progression of resistance to lenvatinib is becoming more prevalent. A series of recent researches have reported the mechanisms underlying the development of lenvatinib resistance in tumor therapy, which are related to the regulation of cell death or proliferation, histological transformation, metabolism, transport processes, and epigenetics. In this review, we aim to outline recent discoveries achieved in terms of the mechanisms and potential predictive biomarkers of lenvatinib resistance as well as to summarize untapped approaches available for improving the therapeutic efficacy of lenvatinib in patients with various types of cancers.

Icariin Regulates EMT and Stem Cell-Like Character in Breast Cancer through Modulating lncRNA NEAT1/TGFβ/SMAD2 Signaling Pathway

Metastases and drug resistance are the major risk factors associated with breast cancer (BC), which is the most common type of tumor affecting females. Icariin (ICA) is a traditional Chinese medicine compound that possesses significant anticancer properties. Long non-coding RNAs (lncRNAs) are involved in a wide variety of biological and pathological processes and have been shown to modulate the effectiveness of certain drugs in cancer. The purpose of this study was to examine the potential effect of ICA on epithelial mesenchymal transition (EMT) and stemness articulation in BC cells, as well as the possible relationship between its inhibitory action on EMT and stemness with the NEAT1/transforming growth factor β (TGFβ)/SMAD2 pathway. The effect of ICA on the proliferation (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and colony assays), EMT (Western blotting, immunofluorescence, and wound healing), and stemness (mammosphere formation assays, Western blotting) of BC cells were examined. According to the findings, ICA suppressed the proliferation, EMT, and stem cell-like in MDA-MB-231 cells, and exerted its inhibitory impact by downregulating the TGFβ/SMAD2 signaling pathway. ICA could significantly downregulate the expression of lncRNA NEAT1, and silencing NEAT1 enhanced the effect of ICA in suppressing EMT and expression of different stem cell markers. In addition, silencing NEAT1 was found to attenuate the TGFβ/SMAD2 signaling pathway, thereby improving the inhibitory impact of ICA on stemness and EMT in BC cells. In conclusion, ICA can potentially inhibit the metastasis of BC via affecting the NEAT1/TGFβ/SMAD2 pathway, which provides a theoretical foundation for understanding the mechanisms involved in potential application of ICA for BC therapy.

ALKBH5 regulates paclitaxel resistance in NSCLC via inhibiting CEMIP-mediated EMT

N6-methyladenosine (m6A) is the most prevalent mRNA modification, and it is verified to be closely correlated with cancer occurrence and progression. The m6A demethylase ALKBH5 (alkB homolog 5) is dysregulated in various cancers. However, the role and underlying mechanism of ALKBH5 in the pathogenesis and especially the chemo-resistance of non-small cell lung cancer (NSCLC) is poorly elucidated. The current study shows that ALKBH5 expression is reduced in paclitaxel (PTX) resistant NSCLC cells and down-regulation of ALKBH5 usually implies poor prognosis of NSCLC patients. Over-expression of ALKBH5 in PTX-resistant cells can suppress cell proliferation and enhance chemo-sensitivity, while knockdown of ALKBH5 exerts the opposite effect, which further supports the tumor suppressive role of ALKBH5. Over-expression of ALKBH5 can also reverse the epithelial-mesenchymal transition (EMT) process in PTX-resistant cancer cells. Mechanistically, data from RNA-seq, real-time PCR and western blotting indicate that CEMIP (cell migration inducing hyaluronidase 1), also known as KIAA1199, may be the downstream target of ALKBH5. Furthermore, ALKBH5 negatively regulates the CEMIP level by reducing the stability of CEMIP mRNA. Collectively, the current data demonstrate that the ALKBH5/CEMIP axis modulates the EMT process in NSCLC, which in turn regulates the chemo-sensitivity of cancer cells to PTX.

Exosomes secreted by metastatic cancer cells promotes epithelial mesenchymal transition in small cell lung carcinoma: The key role of Src/TGF-β1 axis

Exosome-mediated epithelial mesenchymal transition (EMT) is key to cancer metastasis. c-Src is involved in the secretion of exosomes and initiation of EMT. Effects of exosomes from metastatic non-small cell lung carcinoma (NSCLC) cells on the EMT process in primary NSCLC cells were assessed. Levels of c-Src in NSCLC tissues were detected and the influence of exosomes from metastatic NSCLC cells on the exosome secretion and EMT process in primary NSCLC cells was assessed. The expression of c-Src was modulated, and the influence on the secretion of exosomes and EMT initiation was evaluated. The level of c-Src was higher in NSCLC specimen and NSCLC cells with promoted EMT process. The suppression of c-Src inhibited secretion of exosomes. Exosomes from metastatic NSCLC cells enhanced migration and invasion abilities of primary NSCLC cells, which had identical effects to c-Src overexpression. The suppression of c-Src inhibited growth and metastasis of solid tumors as well as secretion of exosomes, while the injection of exosomes with c-Src overexpression promoted lung metastasis. TGF-β1 restored the invasion and migration abilities even with c-Src knockdown. The exosomes from metastatic NSCLC cells with high c-Src expression of can increase c-Src level in primary NSCLC cells, contributing to the promoted EMT process through TGF-β1 pathway.

Shake It Up Baby Now: The Changing Focus on TWIST1 and Epithelial to Mesenchymal Transition in Cancer and Other Diseases

TWIST1 is a transcription factor that is necessary for healthy neural crest migration, mesoderm development, and gastrulation. It functions as a key regulator of epithelial-to-mesenchymal transition (EMT), a process by which cells lose their polarity and gain the ability to migrate. EMT is often reactivated in cancers, where it is strongly associated with tumor cell invasion and metastasis. Early work on TWIST1 in adult tissues focused on its transcriptional targets and how EMT gave rise to metastatic cells. In recent years, the roles of TWIST1 and other EMT factors in cancer have expanded greatly as our understanding of tumor progression has advanced. TWIST1 and related factors are frequently tied to cancer cell stemness and changes in therapeutic responses and thus are now being viewed as attractive therapeutic targets. In this review, we highlight non-metastatic roles for TWIST1 and related EMT factors in cancer and other disorders, discuss recent findings in the areas of therapeutic resistance and stemness in cancer, and comment on the potential to target EMT for therapy. Further research into EMT will inform novel treatment combinations and strategies for advanced cancers and other diseases.

Eudesmane-type sesquiterpenoids from the aerial parts of Artemisia lavandulaefolia and their anti-pancreatic cancer activities

Five undescribed eudesmane sesquiterpenoids, artemilavanins A-E, and one undescribed rearranged eudesmane sesquiterpenoid, artemilavanin F, were isolated from the 95% ethanol extract of the aerial parts of Artemisia lavandulaefolia DC., along with ten known compounds. The structures and configurations of undescribed compounds were mainly elucidated by spectroscopic analyses and single-crystal X-ray diffraction analysis. Among all isolated compounds, artemilavanin F exhibited inhibitory activity on PANC-1 pancreatic cancer cells with IC50 of 9.69 ± 2.39 μM. Artemilavanin F inhibited PANC-1 cell proliferation by induction of G2/M cell cycle arrest and apoptosis mediated by downregulation of cyclin-dependent kinases and accumulation of reactive oxygen species. Moreover, artemilavanin F inhibited the colony formation, cell migration and sphere formation of PANC-1 cells, indicating the suppression of stem-cell-like phenotype of PANC-1 cells. Further results confirmed that the expression of cancer stem cell markers such as Bmi1, CD44, CD133 were inhibited by artemilavanin F. Downregulation of epithelial-mesenchymal transition (EMT) markers such as N-cadherin and Oct-4 indicated the potential of artemilavanin F in prevention of metastasis.

Lovastatin Treatment Inducing Apoptosis in Human Pancreatic Cancer Cells by Inhibiting Cholesterol Rafts in Plasma Membrane and Mitochondria

Resistance to anticancer drugs is a problem in the treatment of pancreatic ductal carcinoma (PDAC) and overcoming it is an important issue. Recently, it has been reported that statins induce apoptosis in cancer cells but the mechanism has not been completely elucidated. We investigated the antitumor mechanisms of statins against PDAC and their impact on resistance to gemcitabine (GEM). Lovastatin (LOVA) increased mitochondrial oxidative stress in PDAC cells, leading to apoptosis. LOVA reduced lipid rafts in the plasma membrane and mitochondria, suppressed the activation of epithelial growth factor receptor (EGFR) and AKT in plasma membrane rafts, and reduced B-cell lymphoma 2 (BCL2)-Bcl-2-associated X protein (BAX) binding and the translocation of F1F0 ATPase in mitochondrial rafts. In the three GEM-resistant cell lines derived from MIA and PANC1, the lipid rafts in the cell membrane and the mitochondria were increased to activate EGFR and AKT and to increase BCL2-BAX binding, which suppressed apoptosis. LOVA abrogated these anti-apoptotic effects by reducing the rafts in the resistant cells. By treating the resistant cells with LOVA, GEM sensitivity improved to the level of the parental cells. Therefore, cholesterol rafts contribute to drug resistance in PDAC. Further clinical research is warranted on overcoming anticancer drug resistance by statin-mediated intracellular cholesterol regulation.

FBXW7 and human tumors: mechanisms of drug resistance and potential therapeutic strategies

Drug therapy, including chemotherapy, targeted therapy, immunotherapy, and endocrine therapy, stands as the foremost therapeutic approach for contemporary human malignancies. However, increasing drug resistance during antineoplastic therapy has become a substantial barrier to favorable outcomes in cancer patients. To enhance the effectiveness of different cancer therapies, an in-depth understanding of the unique mechanisms underlying tumor drug resistance and the subsequent surmounting of antitumor drug resistance is required. Recently, F-box and WD Repeat Domain-containing-7 (FBXW7), a recognized tumor suppressor, has been found to be highly associated with tumor therapy resistance. This review provides a comprehensive summary of the underlying mechanisms through which FBXW7 facilitates the development of drug resistance in cancer. Additionally, this review elucidates the role of FBXW7 in therapeutic resistance of various types of human tumors. The strategies and challenges implicated in overcoming tumor therapy resistance by targeting FBXW7 are also discussed.

Circular RNA nuclear receptor interacting protein 1 promoted biliary tract cancer epithelial-mesenchymal transition and stemness by regulating the miR-515-5p/AKT2 axis and PI3K/AKT/mTOR signaling pathway

Biliary tract cancer (BTC) is a devastating malignancy that is notoriously difficult to diagnose and is associated with high mortality. Circular RNA (circRNA) is a class of endogenous non-coding RNA which has been regarded as the key regulator of tumor initiation and progression, including BTC. Circular RNA nuclear receptor interacting protein 1 (circ_NRIP1), as a circular RNA, is abnormally expressed in many human tumors and exhibits diverse functions in cancer progression. However, its biological significance in BTC has not been thoroughly investigated. In this research, we elucidated that circ_NRIP1 was notably overexpressed in both BTC tissues and cells. We further established a correlation between circ_NRIP1 expression and clinicopathological features in BTC patients, highlighting its clinical relevance. Through functional assays, we observed that knockdown of circ_NRIP1 significantly inhibited tumor cell proliferation, invasion, stemness maintenance, and epithelial-mesenchymal transition, indicating its active involvement in promoting BTC progression. Additionally, it attenuated growth of xenograft and metastasis models. Mechanically, we revealed that circ_NRIP1 served as the competing endogenous RNA to sequester miR-515-5p through complementary base pairing mechanism, thereby upregulated AKT2 expression and indirectly activated PI3K/AKT/mTOR signaling pathway. Generally, targeting the circ_NRIP1/miR-515-5p/AKT2 axis and aberrant activation of the PI3K/AKT/mTOR pathway may hold promising therapeutic strategies for BTC. Our research contributes to a better understanding of the underlying biological basis of BTC and paves the way for the development of innovative treatment approaches.

FOXQ1 promotes pancreatic cancer cell proliferation, tumor stemness, invasion and metastasis through regulation of LDHA-mediated aerobic glycolysis

Pancreatic cancer (PC), a gastrointestinal tract malignant tumor, has a poor prognosis due to early metastasis and limited response to chemotherapy. Therefore, identifying novel therapeutic approaches for PC is critical. Epithelial-mesenchymal transition (EMT) is known as the vital progress in PC development, we constructed the EMT-related prognosis model to screen out that FOXQ1 probably involving in the EMT regulation. FOXQ1 has been linked to the malignant process in a number of cancers. However, its function in PC is unknown. In our work, the expression of FOXQ1 was elevated in PC tissues, and a high level of FOXQ1 in PC was linked to patients' poor prognosis. FOXQ1 overexpression promoted aerobic glycolysis and enhanced PC cell proliferation, tumor stemness, invasion, and metastasis. Whereas, FOXQ1 silencing showed the reverse effect. Furthermore, mechanistic studies indicated that FOXQ1 promotes LDHA transcription, and thus modulates aerobic glycolysis to enhance PC cell proliferation, tumor stemness, invasion, and metastasis by increasing LDHA expression. Therefore, these novel data suggest that FOXQ1 may be a possible therapeutic target in PC.

In vitro and in vivo characterization of [64Cu][Cu(elesclomol)] as a novel theranostic agent for hypoxic solid tumors

PURPOSE

Hypoxic tumors are associated with therapy resistance and poor cancer prognosis, but methods to detect and counter tumor hypoxia remain insufficient. Our purpose was to investigate 64Cu(II)-elesclomol ([64Cu][Cu(ES)]) as a novel theranostic agent for hypoxic tumors, by implementing an improved production method and assessing its therapeutic and diagnostic potential compared to the established Cu-64 radiopharmaceuticals [64Cu]CuCl2 and [diacetyl-bis(N4-methylthiosemicarbazone) [64Cu][Cu(ATSM)].

METHODS

Cu-64 was produced using a biomedical cyclotron at 12 MeV with the reaction 64Ni(p,n)64Cu, followed by synthesis of [64Cu]CuCl2, [64Cu][Cu(ATSM)], and [64Cu][Cu(ES)]. In vitro therapeutic effects were assessed in both normoxic and hypoxic cells (22Rv1 and PC3 prostate cancer cells, and U-87MG glioblastoma cells) using the clonogenic assay and analyzing cellular uptake and internalization. In vivo therapeutic effects were assessed in 22Rv1 xenografts in BALB/cAnN-Foxn1nu/nu/Rj mice receiving a single or multiple doses of radiopharmaceutical, before their feasibility to detect tumor hypoxia was assessed by positron emission tomography (PET) in 22Rv1 and U-87MG xenografts.

RESULTS

In vitro and in vivo studies demonstrated that [64Cu][Cu(ES)] reduced cell survival and inhibited tumor growth more effectively than [64Cu][Cu(ATSM)] and [64Cu]CuCl2. Hypoxia increased the cellular uptake and internalization of [64Cu][Cu(ES)] and [64Cu][Cu(ATSM)]. [64Cu][Cu(ES)]-PET tumor hypoxia detection was feasible and also revealed an unexpected finding of uptake in the brain.

CONCLUSION

To the best of our knowledge, this is the first time that ES is radiolabeled with [64Cu]CuCl2 to [64Cu][Cu(ES)]. We demonstrated superior therapeutic effects of [64Cu][Cu(ES)] compared to [64Cu][Cu(ATSM)] and [64Cu]CuCl2 and that [64Cu][Cu(ES)]-PET is feasible. [64Cu][Cu(ES)] is a promising theranostic agent for hypoxic solid tumors.

ZEB1 promotes DNA homologous recombination repair and contributes to the 5-Fluorouracil resistance in colorectal cancer

Chemotherapy resistance represents a significant obstacle in clinical practice of colorectal cancer (CRC). In this study we aim to clarify the underlying mechanism of chemotherapy resistance mediated by ZEB1 in CRC. shRNA-mediated repression of ZEB1 induced DNA damage in SW480 and RKO cells. Ectopic expression of ZEB1 suppressed the DNA damage caused by ZEB1 knocking down in SW480 and RKO cells. In addition, ZEB1 directly targeted several DNA damage response (DDR) factors including NBS1, RNF8 and RNF168, and thereby the homologous recombination (HR) repair is mediated by ZEB1 via NBS1, RNF8 and RNF168 in CRC cells. Furthermore, ZEB1 maintained chromosome stability in CRC cells. By inducing NBS1, RNF8 and RNF168, ZEB1 is capable of promoting the 5-Fluorouracil (5-FU) resistance in CRC cells via enhancing the DDR signaling and DNA repair. The high expression of ZEB1, NBS1, RNF8 and RNF168 is associated with chemotherapy resistance in primary CRC patients. In conclusion, ZEB1 directly induces the expression of NBS1, RNF8 and RNF168, and thereby enhances DNA HR repair in CRC. The ZEB1-mediated DNA repair contributes to the 5-FU resistance in CRC.

Epigenetic regulation of temozolomide resistance in human cancers with an emphasis on brain tumors: Function of non-coding RNAs

Brain tumors, which are highly malignant, pose a significant threat to health and often result in substantial rates of mortality and morbidity worldwide. The brain cancer therapy has been challenging due to obstacles such as the BBB, which hinders effective delivery of therapeutic agents. Additionally, the emergence of drug resistance further complicates the management of brain tumors. TMZ is utilized in brain cancer removal, but resistance is a drawback. ncRNAs are implicated in various diseases, and their involvement in the cancer is particularly noteworthy. The focus of the current manuscript is to explore the involvement of ncRNAs in controlling drug resistance, specifically in the context of resistance to the chemotherapy drug TMZ. The review emphasizes the function of ncRNAs, particularly miRNAs, in modulating the growth and invasion of brain tumors, which significantly influences their response to TMZ treatment. Through their interactions with various molecular pathways, miRNAs are modulators of TMZ response. Similarly, lncRNAs also associate with molecular pathways and miRNAs, affecting the efficacy of TMZ chemotherapy. Given their functional properties, lncRNAs can either induce or suppress TMZ resistance in brain tumors. Furthermore, circRNAs, which are cancer controllers, regulate miRNAs by acting as sponges, thereby impacting the response to TMZ chemotherapy. The review explores the correlation between ncRNAs and TMZ chemotherapy, shedding light on the underlying molecular pathways involved in this process.

NFAT signaling dysregulation in cancer: Emerging roles in cancer stem cells

The nuclear factor of activated T cells (NFAT) was first identified as a transcriptional regulator of activated T cells. The NFAT family is involved in the development of tumors. Furthermore, recent evidence reveals that NFAT proteins regulate the development of inflammatory and immune responses. New discoveries have also been made about the mechanisms by which NFAT regulates cancer progression through cancer stem cells (CSC). Here, we discuss the role of the NFAT family in the immune system and various cancer types.

The role of epithelial-mesenchymal transition and autophagy in pancreatic ductal adenocarcinoma invasion

Of all pancreatic cancer (PC) cases, approximately 90% are pancreatic ductal adenocarcinoma (PDAC), which progress rapidly due to its high degree of invasiveness and high metastatic potential. Epithelial-mesenchymal transition (EMT) is a prerequisite for cancer cell invasion and spread, and it is mediated by the specific cellular behaviors and the tumor microenvironment. Autophagy has long been a target of cancer therapy, and it has been considered to play a dual and contradictory role, particularly regarding EMT-mediated PDAC invasion. This review discusses the characteristics and the biological role of EMT and autophagy from a cellular perspective, explaining invasion as a survival behavior of PDAC, with the aim of providing novel insights into targeting EMT and autophagy to overcome PDAC invasion.

CircSTK39 suppresses the proliferation and invasion of bladder cancer by regulating the miR-135a-5p/NR3C2-mediated epithelial-mesenchymal transition signaling pathway

Circular RNAs (circRNAs) serve as novel noncoding RNAs that have crucial functions in the development of tumors, including those from bladder cancer (BCa). However, the role and underlying molecular mechanism of circRNAs in mediating the epithelial-mesenchymal transition (EMT) processes in BCa have yet to be studied. In this research, we first found a novel circRNA, circSTK39 (termed as has_circ_0001079), which was a downregulated gene based on the results of high-throughput RNA sequencing. Subsequently, we determined that the expression of circSTK39 in BCa tissues and their cell lines was significantly reduced. In addition, lower circSTK39 expression was strongly related to a worse prognosis for BCa patients. Next, we detected the biological functions of circSTK39 by using loss and gain experiments in vitro and in vivo. Ectopic expression of circSTK39 decreased cell proliferation, colony formation, and invasion capacities, while circSTK39 knockdown prevented the above phenotypes. Mechanically, circSTK39 could sponge with miR-135a-5p, thus inhibiting NR3C2-mediated EMT processes in the BCa progression. In conclusion, our results revealed that circSTK39 inhibited EMT of BCa cells through the miR-135a-5p/NR3C2 axis and may provide promising biomarkers for the diagnosis or prospective therapeutic targets for BCa.

Transcription factor ETV1-induced lncRNA MAFG-AS1 promotes migration, invasion, and epithelial-mesenchymal transition of pancreatic cancer cells by recruiting IGF2BP2 to stabilize ETV1 expression

We investigated the mechanism of ETS-translocation variant 1 (ETV1)/lncRNA-MAFG-AS1 in pancreatic cancer (PC). MAFG-AS1 and ETV1 levels in PC cell lines and HPNE cells were determined using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blotting (WB). After transfection with sh-MAFG-AS1, PC cell invasion, migration, proliferation, and epithelial-mesenchymal transition (EMT)-related proteins were measured by 5-ethynyl-2'-deoxyuridine (EdU), Transwell assay, and WB. The binding between ETV1 and MAFG-AS1 was studied using dual-luciferase assay and chromatin immunoprecipitation. The interactions between MAFG-AS1, IGF2BP2, and ETV1 were tested. Combined experiments were further performed using sh-MAFG-AS1 and pcDNA-ETV1 simultaneously. ETV1/MAFG-AS1 was highly expressed in PC cells. Blocking MAFG-AS1 inhibited the malignant behaviors of PC cells. ETV1 induced MAFG-AS1 transcription in PC cells. MAFG-AS1 stabilized ETV1 mRNA by recruiting IGF2BP2. ETV1 overexpression partially antagonized the suppression of silencing MAFG-AS1 on PC cells. ETV1-induced MAFG-AS1 stabilized the ETV1 expression by recruiting IGF2BP2 and promoted PC cell migration, invasion, proliferation, and EMT.

An Analysis Regarding the Association Between the Nuclear Pore Complex (NPC) and Hepatocellular Carcinoma (HCC)

Background

The nuclear pore complex (NPC) is the main mediator of nuclear and cytoplasmic communication, and delaying or blocking nuclear RNA export and protein shuttling can inhibit cell proliferation and induce apoptosis. Although NPC is a research hotspot in structural biology, relevant studies in hepatocellular carcinoma are scarce, especially in terms of translation into clinical practice.

Methods

This study used a bioinformatics approach combining validation experiments to investigate the biological mechanisms that may be related with NPC. A series of experiments performed to explore the function of the Targeting protein for Xenopus kinesin-like protein 2 (TPX2) in HCC.

Results

Patients with HCC can be divided into two NPC clusters. Patients with high NPC levels (C1) had a shorter survival time than those with low NPC levels (C2) and are characterised by high levels of proliferative signals. We demonstrated that TPX2 regulates HCC growth and inhibits apoptosis in an NPC-dependent manner and contributes to the maintenance of HCC stemness. We developed the NPCScore to predict the prognosis and degree of differentiation in HCC patients.

Conclusion

NPC plays an important role in the malignant proliferation of HCC. Assessing NPC expression patterns could help enhance our understanding of tumor cell proliferation and could guide more effective chemotherapeutic strategies.

Roles of circRNA dysregulation in esophageal squamous cell carcinoma tumor microenvironment

Esophageal squamous cell carcinoma (ESCC) is the most prevalent histological esophageal cancer characterized by advanced diagnosis, metastasis, resistance to treatment, and frequent recurrence. In recent years, numerous human disorders such as ESCC, have been linked to abnormal expression of circular RNAs (circRNAs), suggesting that they are fundamental to the intricate system of gene regulation that governs ESCC formation. The tumor microenvironment (TME), referring to the area surrounding the tumor cells, is composed of multiple components, including stromal cells, immune cells, the vascular system, extracellular matrix (ECM), and numerous signaling molecules. In this review, we briefly described the biological purposes and mechanisms of aberrant circRNA expression in the TME of ESCC, including the immune microenvironment, angiogenesis, epithelial-to-mesenchymal transition, hypoxia, metabolism, and radiotherapy resistance. As in-depth research into the processes of circRNAs in the TME of ESCC continues, circRNAs are promising therapeutic targets or delivery systems for cancer therapy and diagnostic and prognostic indicators for ESCC.

Tumor Microenvironment Role in Pancreatic Cancer Stem Cells

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy with a majority of patients presenting with unresectable or metastatic disease, resulting in a poor 5-year survival rate. This, in turn, is due to a highly complex tumor microenvironment and the presence of cancer stem cells, both of which induce therapy resistance and tumor relapse. Therefore, understanding and targeting the tumor microenvironment and cancer stem cells may be key strategies for designing effective PDAC therapies. In the present review, we summarized recent advances in the role of tumor microenvironment in pancreatic neoplastic progression.

Multi-Targeted and On-Demand Non-Coding RNA Regulation Nanoplatform against Metastasis and Recurrence of Triple-Negative Breast Cancer

Dysregulation of microRNAs (miRs) is the hallmark of triple-negative breast cancer (TNBC), which is closely involved with its growth, metastasis, and recurrence. Dysregulated miRs are promising targets for TNBC therapy, however, targeted and accurate regulation of multiple disordered miRs in tumors is still a great challenge. Here, a multi-targeting and on-demand non-coding RNA regulation nanoplatform (MTOR) is reported to precisely regulate disordered miRs, leading to dramatical suppression of TNBC growth, metastasis, and recurrence. With the assistance of long blood circulation, ligands of urokinase-type plasminogen activator peptide and hyaluronan located in multi-functional shells enable MTOR to actively target TNBC cells and breast cancer stem cell-like cells (BrCSCs). After entering TNBC cells and BrCSCs, MTOR is subjected to lysosomal hyaluronidase-induced shell detachment, leading to an explosion of the TAT-enriched core, thereby enhancing nuclear targeting. Subsequently, MTOR could precisely and simultaneously downregulate microRNA-21 expression and upregulate microRNA-205 expression in TNBC. In subcutaneous xenograft, orthotopic xenograft, pulmonary metastasis, and recurrence TNBC mouse models, MTOR shows remarkably synergetic effects on the inhibition of tumor growth, metastasis, and recurrence due to its on-demand regulation of disordered miRs. This MTOR system opens a new avenue for on-demand regulation of disordered miRs against growth, metastasis, and recurrence of TNBC.

Exploration and Validation of Pancreatic Cancer Hub Genes Based on Weighted Gene Co-Expression Network Analysis and Immune Infiltration Score Analysis

Objective

To find pancreatic cancer (PC)-related hub genes based on weighted gene co-expression network analysis (WGCNA) construction and immune infiltration score analysis and validate them immunohistochemically by clinical cases, to generate new concepts or therapeutic targets for the early diagnosis and treatment of PC.

Material and Methods

In this study, WGCNA and immune infiltration score were utilized to identify the relevant core modules of PC and the hub genes within these core modules.

Results

Using WGCNA analysis, data from PC and normal pancreas integrated with TCGA and GTEX were analyzed and brown modules were chosen from the six modules. Five hub genes, including DPYD, FXYD6, MAP6, FAM110B, and ANK2, were discovered to have differential survival significance via validation tests utilizing survival analysis curves and the GEPIA database. The DPYD gene was the only gene associated with PC survival side effects. Validation of the Human Protein Atlas (HPA) database and immunohistochemical testing of clinical samples showed positive results for DPYD expression in PC.

Conclusion

In this study, we identified DPYD, FXYD6, MAP6, FAM110B, and ANK2, as immune-related candidate markers for PC. Only the DPYD gene had a negative impact on the survival of PC patients. Through validation of the HPA database and immunohistochemical testing of clinical cases, we believe that the DPYD gene brings novel ideas and therapeutic targets in the diagnosis and treatment of PC.

Targeting HMGA1 contributes to immunotherapy in aggressive breast cancer while suppressing EMT

Metastasis is an obstacle to the clinical treatment of aggressive breast cancer (BC). Studies have shown that high mobility group A1 (HMGA1) is abnormally expressed in various cancers and mediates tumor proliferation and metastasis. Here, we provided more evidence that HMGA1 mediated epithelial to mesenchymal transition (EMT) through the Wnt/β-catenin pathway in aggressive BC. More importantly, HMGA1 knockdown enhanced antitumor immunity and improved the response to immune checkpoint blockade (ICB) therapy by upregulating programmed cell death ligand 1 (PD-L1) expression. Simultaneously, we revealed a novel mechanism by which HMGA1 and PD-L1 were regulated by the PD-L1/HMGA1/Wnt/β-catenin negative feedback loop in aggressive BC. Taken together, we believe that HMGA1 can serve as a target for the dual role of anti-metastasis and enhancing immunotherapeutic responses.

Cancer Stem Cells in Pancreatic Ductal Adenocarcinoma

The first discovery of cancer stem cells (CSCs) in leukaemia triggered active research on stemness in neoplastic tissues. CSCs represent a subpopulation of malignant cells, defined by unique properties: a dedifferentiated state, self-renewal, pluripotency, an inherent resistance to chemo- and radiotherapy, the presence of certain epigenetic alterations, as well as a higher tumorigenicity in comparison with the general population of cancer cells. A combination of these features highlights CSCs as a high-priority target during cancer treatment. The presence of CSCs has been confirmed in multiple malignancies, including pancreatic ductal adenocarcinoma, an entity that is well known for its dismal prognosis. As the aggressive course of pancreatic carcinoma is partly attributable to treatment resistance, CSCs could contribute to adverse outcomes. The aim of this review is to summarize the current information regarding the markers and molecular features of CSCs in pancreatic ductal adenocarcinoma and the therapeutic options to remove them.

Circular RNAs in chemotherapy resistance of lung cancer and their potential therapeutic application

Lung cancer is one of the high malignancy-related incidence and mortality worldwide, accounting for about 13% of total cancer diagnoses. Currently, the use of anti-cancer agents is still the main therapeutic method for lung cancer. However, cancer cells will gradually show resistance to these drugs with the progress of treatment. And the molecular mechanisms underlying chemotherapy agents resistance remain unclear. circRNAs are newly identified noncoding RNAs molecules with covalently closed circular structures. Previous studies have shown that circRNAs are associated with tumorigenesis and progression of various cancers, including lung cancer. Recently, growing reports have suggested that circRNAs could contribute to drug resistance of lung cancer cell through different mechanisms. Therefore, in this review, we summarized the functions and underlying mechanisms of circRNAs in regulating chemoresistance of lung cancer and discussed their potential applications for diagnosis, prognosis, and treatment of lung cancer.

Aspirin increases the efficacy of gemcitabine in pancreatic cancer by modulating the PI3K/AKT/mTOR signaling pathway and reversing epithelial‑mesenchymal transition

Gemcitabine is regarded as a standard medication for patients with pancreatic cancer. The aim of the present study was to investigate the impact of aspirin (ASA) on the efficacy of gemcitabine in pancreatic cancer and the potential mechanism. The SW1990 and BxPC-3 human pancreatic cell lines were treated with 2 mmol/l ASA and/or 1 mg/l gemcitabine. The effects of the treatments were tested on the viability, migration and invasion of the cells using MTT, wound healing and Transwell invasion assays. In addition, cell apoptosis was evaluated via flow cytometry with Annexin V-FITC/PI and the western blotting of Bax and Bcl-2. The expression of epithelial-mesenchymal transition (EMT)-associated proteins and activation of the PI3K/AKT/mTOR pathway were also assessed using western blotting. The results reveal that ASA increased the efficacy of gemcitabine in reducing the proliferation, migration and invasion of pancreatic cancer cells and increasing their apoptosis. These effects are associated with inhibition of the PI3K/AKT/mTOR pathway and the reversal of EMT. Thus, the combined use of ASA and gemcitabine is suggested to be a potential therapeutic strategy for patients with pancreatic cancer.

Pancreatic cancer cells upregulate LPAR4 in response to isolation stress to promote an ECM-enriched niche and support tumour initiation

Defining drivers of tumour initiation can provide opportunities to control cancer progression. Here we report that lysophosphatidic acid receptor 4 (LPAR4) becomes transiently upregulated on pancreatic cancer cells exposed to environmental stress or chemotherapy where it promotes stress tolerance, drug resistance, self-renewal and tumour initiation. Pancreatic cancer cells gain LPAR4 expression in response to stress by downregulating a tumour suppressor, miR-139-5p. Even in the absence of exogenous lysophosphatidic acid, LPAR4-expressing tumour cells display an enrichment of extracellular matrix genes that are established drivers of cancer stemness. Mechanistically, upregulation of fibronectin via an LPAR4/AKT/CREB axis is indispensable for LPAR4-induced tumour initiation and stress tolerance. Moreover, ligation of this fibronectin-containing matrix via integrins α5β1 or αVβ3 can transfer stress tolerance to LPAR4-negative cells. Therefore, stress- or drug-induced LPAR4 enhances cell-autonomous production of a fibronectin-rich extracellular matrix, allowing cells to survive 'isolation stress' and compensate for the absence of stromal-derived factors by creating their own tumour-initiating niche.

Examining the efficacy of localised gemcitabine therapy for the treatment of pancreatic cancer using a hybrid agent-based model

The prognosis for pancreatic ductal adenocarcinoma (PDAC) patients has not significantly improved in the past 3 decades, highlighting the need for more effective treatment approaches. Poor patient outcomes and lack of response to therapy can be attributed, in part, to a lack of uptake of perfusion of systemically administered chemotherapeutic drugs into the tumour. Wet-spun alginate fibres loaded with the chemotherapeutic agent gemcitabine have been developed as a potential tool for overcoming the barriers in delivery of systemically administrated drugs to the PDAC tumour microenvironment by delivering high concentrations of drug to the tumour directly over an extended period. While exciting, the practicality, safety, and effectiveness of these devices in a clinical setting requires further investigation. Furthermore, an in-depth assessment of the drug-release rate from these devices needs to be undertaken to determine whether an optimal release profile exists. Using a hybrid computational model (agent-based model and partial differential equation system), we developed a simulation of pancreatic tumour growth and response to treatment with gemcitabine loaded alginate fibres. The model was calibrated using in vitro and in vivo data and simulated using a finite volume method discretisation. We then used the model to compare different intratumoural implantation protocols and gemcitabine-release rates. In our model, the primary driver of pancreatic tumour growth was the rate of tumour cell division. We were able to demonstrate that intratumoural placement of gemcitabine loaded fibres was more effective than peritumoural placement. Additionally, we quantified the efficacy of different release profiles from the implanted fibres that have not yet been tested experimentally. Altogether, the model developed here is a tool that can be used to investigate other drug delivery devices to improve the arsenal of treatments available for PDAC and other difficult-to-treat cancers in the future.

Identification of EMT-related alternative splicing event of TMC7 to promote invasion and migration of pancreatic cancer

Objective

Epithelial-to-mesenchymal transition (EMT) is tightly associated with the invasion and metastasis of pancreatic cancer with rapid progression and poor prognosis. Notably, gene alternative splicing (AS) event plays a critical role in regulating the progression of pancreatic cancer. Therefore, this study aims to identify the EMT-related AS event in pancreatic cancer.

Methods

The EMT-related gene sets, transcriptomes, and matched clinical data were obtained from the MSigDB, The Cancer Genome Atlas (TCGA), International Cancer Genome Consortium (ICGC), and Gene Expression Omnibus (GEO) databases. Key gene AS events associated with liver metastasis were identified by prognostic analysis, gene set variation analysis (GSVA), and correlation analysis in pancreatic cancer. The cell line and organoid model was constructed to evaluate these key gene AS events in regulating pancreatic cancer in vitro. Furthermore, we established an EMT-related gene set consisting of 13 genes by prognostic analysis, the role of which was validated in two other databases. Finally, the human pancreatic cancer tissue and organoid model was used to evaluate the correlation between the enrichment of this gene set and liver metastasis.

Results

Prognostic analysis and correlation analysis revealed that eight AS events were closely associated with the prognosis of pancreatic cancer. Furthermore, the expression of TMC7 and CHECK1 AS events was increased in the metastatic lesions of the human tissue and organoid model. Additionally, the knockdown of exon 17 of TMC7 significantly inhibited the proliferation, invasion, and migration of pancreatic cancer cells in 2D and 3D cell experiments. Finally, the expression of exon 17 of TMC17 exhibited a significant correlation with the poor prognosis in pancreatic ductal adenocarcinoma (PDAC).

Conclusion

The AS events of TMC7 and CHECK1 were associated with liver metastasis in pancreatic cancer. Moreover, exon 17 of TMC7 could be a potential therapeutic target in pancreatic cancer.

Collagen type VII α1 chain: A promising prognostic and immune infiltration biomarker of pancreatic cancer

Pancreatic cancer (PC) is a stubborn malignancy with high lethality and a low 5-year overall survival (OS) rate. Collagen type VII α1 chain (COL7A1), a major component of the extracellular matrix, serves important roles in numerous physiological processes and various illnesses. COL7A1 protein acts as an anchoring fibril between the external epithelial cells and the underlying stroma, and mutation of COL7A1 could cause recessive dystrophic epidermolysis bullosa. Raw data for PC were acquired from The Cancer Genome Atlas and the Gene Expression Omnibus database, and raw data for the normal pancreas were obtained from the Genotype-Tissue Expression database. COL7A1 mRNA expression in PC tissues was compared with that in either paired (GSE15471 dataset) or unpaired (all other data) normal pancreas tissues. The association between COL7A1 mRNA expression and clinicopathological factors was assessed using logistic regression analysis. Cox analysis and Kaplan-Meier analysis were used to evaluate the role of COL7A1 mRNA expression in prognosis and nomograms were constructed. Gene Ontology analysis, Kyoto Encyclopedia of Genes and Genomes analysis, Gene Set Enrichment Analysis (GSEA) and single-sample GSEA (ssGSEA) were performed to evaluate the relevant functions of COL7A1 and correlation with immune cell infiltration. Furthermore, reverse transcription-quantitative PCR was used to assess the mRNA expression levels of COL7A1 in PC. The present study demonstrated that COL7A1 mRNA expression was higher in PC tissues compared with in normal pancreas tissues. The Kaplan-Meier survival analysis indicated that patients with PC with high COL7A1 mRNA expression had shorter overall survival (OS), disease-specific survival (DSS) and progression-free interval (PFI) times compared with patients with PC with low COL7A1 mRNA expression. Multivariate analysis demonstrated that COL7A1 mRNA expression was an independent risk factor for OS, DSS and PFI. Nomogram and calibration plots were constructed to predict the prognosis of patients with PC. GSEA demonstrated that high mRNA expression levels of COL7A1 were associated with multiple cancer-related pathways. ssGSEA analysis indicated that COL7A1 expression was positively associated with natural killer CD56bright cells and T helper (Th)2 cells, and negatively associated with Th17 cells and eosinophils. The results of the present study suggested that COL7A1 could be an independent biomarker and an influential moderator of immune infiltration in PC.

Mutant p53 driven-LINC00857, a protein scaffold between FOXM1 and deubiquitinase OTUB1, promotes the metastasis of pancreatic cancer

Tumour metastasis is the major adverse factor for recurrence and death in pancreatic cancer (PC) patients. P53 mutations are considered to be the second most common type of mutation in PC and significantly promote PC metastasis. However, the molecular mechanisms underlying the effects of p53 mutations, especially the regulatory relationship of the protein with long noncoding RNAs (lncRNAs), remain unclear. In the present study, we demonstrated that the lncRNA LINC00857 exhibits a significantly elevated level in PC and that it is associated with poor prognosis; furthermore, TCGA data showed that LINC00857 expression was significantly upregulated in the mutant p53 group compared with the wild-type p53 group. Gain- and loss-of-function experiments showed that LINC00857 promotes the metastasis of PC cells. We further found that LINC00857 upregulates FOXM1 protein expression and thus accelerates metastasis in vitro and in vivo. Mechanistically, LINC00857 bound simultaneously to FOXM1 and to the deubiquitinase OTUB1, thereby serving as a protein scaffold and enhancing the interaction between FOXM1 and OTUB1, which inhibits FOXM1 degradation through the ubiquitin-proteasome pathway. Interestingly, we found that mutant p53 promotes LINC00857 transcription by binding to its promoter region. Finally, atorvastatin, a commonly prescribe lipid-lowering drug, appeared to inhibit PC metastasis by inhibiting the mutant p53-LINC00857 axis. Taken together, our results provide new insights into the biology driving PC metastasis and indicate that the mutant p53-LINC00857 axis might represent a novel therapeutic target for PC metastasis.

TWIST1 Plays Role in Expression of Stemness State Markers in ESCC

BACKGROUND

Stemness markers play critical roles in the maintenance of key properties of embryonic stem cells (ESCs), including the pluripotency, stemness state, and self-renewal capacities, as well as cell fate decision. Some of these features are present in cancer stem cells (CSCs). TWIST1, as a bHLH transcription factor oncogene, is involved in the epithelial-mesenchymal transition (EMT) process in both embryonic and cancer development. Our aim in this study was to investigate the functional correlation between TWIST1 and the involved genes in the process of CSCs self-renewal in human esophageal squamous cell carcinoma (ESCC) line KYSE-30.

METHODS

TWIST1 overexpression was enforced in the ESCC KYSE-30 cells using retroviral vector containing the specific pruf-IRES-GFP-hTWIST1 sequence. Following RNA extraction and cDNA synthesis, the mRNA expression profile of TWIST1 and the stem cell markers, including BMI1, CRIPTO1, DPPA2, KLF4, SOX2, NANOG, and MSI1, were assessed using relative comparative real-time PCR.

RESULTS

Ectopic expression of TWIST1 in KYSE-30 cells resulted in an increased expression of TWIST1 compared to control GFP cells by nearly 9-fold. Transduction of TWIST1-retroviral particles caused a significant enhancement in BMI1, CRIPTO1, DPPA2, KLF4, and SOX2 mRNA expression, approximately 4.5-, 3.2-, 5.5-, 3.5-, and 3.7-folds, respectively, whereas this increased TWIST1 expression caused no change in the mRNA expression of NANOG and MSI1 genes.

CONCLUSIONS

TWIST1 gene ectopic expression in KYSE-30 cells enhanced the level of cancer stem cell markers' mRNA expression. These results may emphasize the role of TWIST1 in the self-renewal process and may corroborate the involvement of TWIST1 in the stemness state capacity of ESCC cell line KYSE-30, as well as its potential as a therapeutic target.