EMT and Treatment Resistance in Pancreatic Cancer. Cancers (Basel). 2017;9:pii: E122. [PMID: 28895920 PMCID: PMC5615337 DOI: 10.3390/cancers9090122]

CCL3 predicts exceptional response to TGFβ inhibition in basal-like pancreatic cancer enriched in LIF-producing macrophages

The TGFβ receptor inhibitor galunisertib showed promising efficacy in patients with pancreatic ductal adenocarcinoma (PDAC) in the phase 2 H9H-MC-JBAJ study. Identifying biomarkers for this treatment remains essential. Baseline plasma levels of chemokine CCL3 were integrated with clinical outcomes in PDAC patients treated with galunisertib plus gemcitabine (n = 104) or placebo plus gemcitabine (n = 52). High CCL3 was a poor prognostic factor in the placebo group (mOS 3.6 vs. 10.1 months; p < 0.01) but a positive predictor for galunisertib (mOS 9.2 vs. 3.6 months; p < 0.01). Mechanistically, tumor-derived CCL3 activates Tgfβ signaling in macrophages, inducing their M2 phenotype and Lif secretion, sustaining a mesenchymal/basal-like ecotype. TGFβ inhibition redirects macrophage polarization to M1, reducing Lif and shifting PDAC cells to a more epithelial/classical phenotype, improving gemcitabine sensitivity. This study supports exploring TGFβ-targeting agents in PDAC with a mesenchymal/basal-like ecotype driven by high CCL3 levels.

Pin1: Advances in pancreatic cancer therapeutic potential and inhibitors research

The peptidyl-prolyl cis/trans isomerase NIMA-interaction 1 (Pin1) catalyzes the transition of the proline ring from the cis to trans conformation, resulting in conformational and functional changes in proteins that are regulated by proline-guided serine/threonine phosphorylation. In recent years, Pin1 has emerged as a novel molecular target for the diagnosis and treatment of various malignant tumors. Notably, it has been found that Pin1 is highly expressed in pancreatic cancer. This article focuses on the mechanisms by which Pin1 orchestrates multiple oncogenic functions in the development of pancreatic cancer. By exploring the intricate interactions between Pin1 and the pancreatic tumor microenvironment, we provide an overview of Pin1's role in modifying glycolytic metabolism, redox balance, and the hypoxic microenvironment of pancreatic cancer. Furthermore, we summarize the potential anticancer effects of Pin1 inhibitors, aiming to elucidate Pin1's promise as a potential anticancer agent, particularly in the context of pancreatic cancer.

Hsp90α promotes chemoresistance in pancreatic cancer by regulating Keap1-Nrf2 axis and inhibiting ferroptosis

Chemoresistance is the primary reason for poor prognosis in patients with pancreatic cancer (PC). Recent studies have indicated that ferroptosis may improve chemoresistance, but the underlying mechanisms remain unclear. In this study, significant upregulation of heat shock protein 90α (Hsp90α) expression is detected in the peripheral blood and tissue samples of patients with chemoresistant PC. Further studies reveal that Hsp90α promotes the proliferation, migration, and invasion of a chemoresistant pancreatic cell line (Panc-1-gem) by suppressing ferroptosis. Hsp90α competitively binds to Kelch-like ECH-associated protein 1 (Keap1), liberating nuclear factor erythroid 2-related factor 2 (Nrf2) from Keap1 sequestration. Nrf2 subsequently translocates into the nucleus and activates the glutathione peroxidase 4 (GPX4) pathway, thereby suppressing ferroptosis. This process further worsens the chemoresistance of PC cells. This study provides valuable insight into potential molecular targets to overcome chemoresistance in PC. It sheds light on the intricate mechanisms linking Hsp90α and ferroptosis to chemoresistance in PC and provides a theoretical foundation for the development of novel therapeutic strategies.

Insights into gemcitabine resistance in pancreatic cancer: association with metabolic reprogramming and TP53 pathogenicity in patient derived xenografts

BACKGROUND

With poor prognosis and high mortality, pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies. Standard of care therapies for PDAC have included gemcitabine for the past three decades, although resistance often develops within weeks of chemotherapy initiation through an array of possible mechanisms.

METHODS

We reanalyzed publicly available RNA-seq gene expression profiles of 28 PDAC patient-derived xenograft (PDX) models before and after a 21-day gemcitabine treatment using our validated analysis pipeline to identify molecular markers of intrinsic and acquired resistance.

RESULTS

Using normalized RNA-seq quantification measurements, we first identified oxidative phosphorylation and interferon alpha pathways as the two most enriched cancer hallmark gene sets in the baseline gene expression profile associated with intrinsic gemcitabine resistance and sensitivity, respectively. Furthermore, we discovered strong correlations between drug-induced expression changes in glycolysis and oxidative phosphorylation genes and response to gemcitabine, which suggests that these pathways may be associated with acquired gemcitabine resistance mechanisms. Thus, we developed prediction models using baseline gene expression profiles in those pathways and validated them in another dataset of 12 PDAC models from Novartis. We also developed prediction models based on drug-induced expression changes in genes from the Molecular Signatures Database (MSigDB)'s curated 50 cancer hallmark gene sets. Finally, pathogenic TP53 mutations correlated with treatment resistance.

CONCLUSION

Our results demonstrate that concurrent upregulation of both glycolysis and oxidative phosphorylation pathways occurs in vivo in PDAC PDXs following gemcitabine treatment and that pathogenic TP53 status had association with gemcitabine resistance in these models. Our findings may elucidate the molecular basis for gemcitabine resistance and provide insights for effective drug combination in PDAC chemotherapy.

IFIT1 modulates the proliferation, migration and invasion of pancreatic cancer cells via Wnt/β-catenin signaling

OBJECTIVES

Previously, Interferon-induced Protein with Tetratricopeptide Repeats 1 (IFIT1) has been shown to promote cancer development. Here, we aimed to explore the role of IFIT1 in the development and progression of pancreatic cancer, including the underlying mechanisms.

METHODS

We explored IFIT1 expression in pancreatic cancer samples using The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets. Cell Counting Kit-8 (CCK8), colony formation, scratch wound-healing and Transwell assays were performed to assess the proliferation, migration and invasion abilities of pancreatic cancer cells. Gene Set Enrichment Analysis (GSEA) and Western blotting were performed to assess the regulatory effect of IFIT1 on the Wnt/β-catenin pathway.

RESULTS

We found that upregulation of IFIT1 expression is common in pancreatic cancer and is negatively associated with overall patient survival. Knockdown of IFIT1 expression led to decreased proliferation, migration and invasion of pancreatic cancer cells. We also found that IFIT1 could regulate Wnt/β-catenin signaling, and that a Wnt/β-catenin agonist could reverse this effect. In addition, we found that IFIT1 can promote epithelial-mesenchymal transition (EMT) of pancreatic cancer cells.

CONCLUSIONS

Our data indicate that IFIT1 increases pancreatic cancer cell proliferation, migration and invasion by activating the Wnt/β-catenin pathway. In addition, we found that EMT could be regulated by IFIT1. IFIT1 may serve as a potential therapeutic target for pancreatic cancer.

Targeting the pancreatic tumor microenvironment by plant-derived products and their nanoformulations

Pancreatic cancer remains a significant health issue with limited treatment options. The tumor stroma, a complex environment made up of different cells and proteins, plays a crucial role in tumor growth and chemoresistance. Targeting tumor stroma, consisting of diverse non-tumor cells such as fibroblasts, extracellular matrix (ECM), immune cells, and also pre-vascular cells is encouraging for remodeling solid cancers, such as pancreatic cancer. Remodeling the stroma of pancreas tumors can be suggested as a strategy for reducing resistance to chemo/immunotherapy. Several studies have shown that phytochemicals from plants can affect the tumor environment and have anti-cancer properties. By targeting key pathways involved in stromal activation, phytochemicals may disrupt communication between the tumor and stroma and make tumor cells more sensitive to different treatments. Additionally, phytochemicals have immunomodulatory and anti-angiogenic properties, all of which contribute to their potential in treating pancreatic cancer. This review will provide a detailed look at how phytochemicals impact the tumor stroma and their effects on pancreatic tumor growth, spread, and response to treatment. It will also explore the potential of combining phytochemicals with other treatment options like chemotherapy, immunotherapy, and radiation.

Tivozanib-induced activation of the mitochondrial apoptotic pathway and suppression of epithelial-to-mesenchymal transition in oral squamous cell carcinoma

The potential of tivozanib as a treatment for oral squamous cell carcinoma (OSCC) was explored in this study. We investigated the effects of tivozanib on OSCC using the Ca9-22 and CAL27 cell lines. OSCC is a highly prevalent cancer type with a significant risk of lymphatic metastasis and recurrence, which necessitates the development of innovative treatment approaches. Tivozanib, a vascular endothelial growth factor receptor inhibitor, has shown efficacy in inhibiting neovascularization in various cancer types but has not been thoroughly studied in OSCC. Our comprehensive assessment revealed that tivozanib effectively inhibited OSCC cells. This was accompanied by the suppression of Bcl-2, a reduction in matrix metalloproteinase levels, and the induction of intrinsic pathway-mediated apoptosis. Furthermore, tivozanib contributed to epithelial-to-mesenchymal transition (EMT) inhibition by increasing E-cadherin levels while decreasing N-cadherin levels. These findings highlight the substantial anticancer potential of tivozanib in OSCC and thus its promise as a therapeutic option. Beyond reducing cell viability and inducing apoptosis, the capacity of tivozanib to inhibit EMT and modulate key proteins presents the possibility of a paradigm shift in OSCC treatment.

Epithelial and Mesenchymal-like Pancreatic Cancer Cells Exhibit Different Stem Cell Phenotypes Associated with Different Metastatic Propensities

Pancreatic ductal adenocarcinoma (PDAC) is mostly diagnosed at advanced or even metastasized stages, limiting the prognoses of patients. Metastasis requires high tumor cell plasticity, implying phenotypic switching in response to changing environments. Here, epithelial-mesenchymal transition (EMT), being associated with an increase in cancer stem cell (CSC) properties, and its reversion are important. Since it is poorly understood whether different CSC phenotypes exist along the EMT axis and how these impact malignancy-associated properties, we aimed to characterize CSC populations of epithelial and mesenchymal-like PDAC cells. Single-cell cloning revealed CSC (Holoclone) and non-CSC (Paraclone) clones from the PDAC cell lines Panc1 and Panc89. The Panc1 Holoclone cells showed a mesenchymal-like phenotype, dominated by a high expression of the stemness marker Nestin, while the Panc89 Holoclone cells exhibited a SOX2-dominated epithelial phenotype. The Panc89 Holoclone cells showed enhanced cell growth and a self-renewal capacity but slow cluster-like invasion. Contrarily, the Panc1 Holoclone cells showed slower cell growth and self-renewal ability but were highly invasive. Moreover, cell variants differentially responded to chemotherapy. In vivo, the Panc1 and Panc89 cell variants significantly differed regarding the number and size of metastases, as well as organ manifestation, leading to different survival outcomes. Overall, these data support the existence of different CSC phenotypes along the EMT axis in PDAC, manifesting different metastatic propensities.

Roles, underlying mechanisms and clinical significances of LINC01503 in human cancers

Long intergenic non-coding RNA 01503 (LINC01503) is a long non-coding RNA (lncRNA) located on human chromosome 9q34.11. There is compelling evidence indicating that LINC01503 is upregulated in multiple types of tumors and functions as a tumor stimulator. The upregulation of LINC01503 was significantly associated with the risk of 12 tumors and showed a strong correlation with clinicopathological characteristics and poor prognosis in 9 tumors. The expression of LINC01503 is regulated by transcription factors such as TP63, EGR1, c-MYC, GATA1 and AR. The downstream regulatory mechanisms of LINC01503 are complex and multifaceted. LINC01503, as a competing endogenous RNA (ceRNA), regulates gene expression by competitively inhibiting miRNA. LINC01503 may also regulate gene expression via interacting with biomolecules or recruiting chromatin-modifying complexes. In addition, LINC01503 can abnormally activate the ERK/MAPK, PI3K/AKT and Wnt/β-catenin signaling pathways to enhance tumor progression. Here, this review presents an overview of the latest research progress of LINC01503 in the field of oncology, summarizes its comprehensive network involved in multiple cancer molecular mechanisms, and explores its potential applications in cancer diagnosis, prognosis, and treatment.

Study on tumour cell-derived hybrid exosomes as dasatinib nanocarriers for pancreatic cancer therapy

Pancreatic ductal adenocarcinoma (PDAC) is one of the leading causes of cancer-related death. Therefore, we intend to explore novel strategies against PDAC. The exosomes-based biomimetic nanoparticle is an appealing candidate served as a drug carrier in cancer treatment, due to its inherit abilities. In the present study, we designed dasatinib-loaded hybrid exosomes by fusing human pancreatic cancer cells derived exosomes with dasatinib-loaded liposomes, followed by characterization for particle size (119.9 ± 6.10 nm) and zeta potential (-11.45 ± 2.24 mV). Major protein analysis from western blot techniques reveal the presence of exosome marker proteins CD9 and CD81. PEGylated hybrid exosomes showed pH-sensitive drug release in acidic condition, benefiting drug delivery to acidic cancer environment. Dasatinib-loaded hybrid exosomes exhibited significantly higher uptake rates and cytotoxicity to parent PDAC cells by two-sample t-test or by one-way ANOVA analysis of variance, as compared to free drug or liposomal formulations. The results from our computational analysis demonstrated that the drug-likeness, ADMET, and protein-ligand binding affinity of dasatinib are verified successfully. Cancer derived hybrid exosomes may serve as a potential therapeutic candidate for pancreatic cancer treatment.

Molecular Networks of Platinum Drugs and Their Interaction with microRNAs in Cancer

The precise mechanism of resistance to anti-cancer drugs such as platinum drugs is not fully revealed. To reveal the mechanism of drug resistance, the molecular networks of anti-cancer drugs such as cisplatin, carboplatin, oxaliplatin, and arsenic trioxide were analyzed in several types of cancers. Since diffuse-type stomach adenocarcinoma, which has epithelial-mesenchymal transition (EMT)-like characteristics, is more malignant than intestinal-type stomach adenocarcinoma, the gene expression and molecular networks in diffuse- and intestinal-type stomach adenocarcinomas were analyzed. Analysis of carboplatin revealed the causal network in diffuse large B-cell lymphoma. The upstream regulators of the molecular networks of cisplatin-treated lung adenocarcinoma included the anti-cancer drug trichostatin A (TSA), a histone deacetylase inhibitor. The upstream regulator analysis of cisplatin revealed an increase in FAS, BTG2, SESN1, and CDKN1A, and the involvement of the tumor microenvironment pathway. The molecular networks were predicted to interact with several microRNAs, which may contribute to the identification of new drug targets for drug-resistant cancer. Analysis of oxaliplatin, a platinum drug, revealed that the SPINK1 pancreatic cancer pathway is inactivated in ischemic cardiomyopathy. The study showed the importance of the molecular networks of anti-cancer drugs and tumor microenvironment in the treatment of cancer resistant to anti-cancer drugs.

m6 A reader YTHDF3 triggers the progression of hepatocellular carcinoma through the YTHDF3/m6 A-EGFR/STAT3 axis and EMT

Hepatocellular carcinoma (HCC) is the sixth most common cancer and the fourth leading cause of tumor-related deaths worldwide. N6-methyladenosine (m6 A) mediates RNA metabolism in tumor biology. However, the regulatory role of YTHDF3, an m6 A reader, in HCC progression and its underlying mechanisms remains unclear. Therefore, this study aims to investigate the oncogenic effect of YTHDF3 on HCC progression via the epigenetic regulation of m6 A-modified mRNAs. The expression levels of YTHDF3 in HCC tissues and matched adjacent liver tissues were detected using western blot analysis, immunohistochemistry, and quantitative real-time polymerase chain reaction. The function of YTHDF3 in HCC progression and its underlying mechanisms have been studied both in vitro and in vivo. YTHDF3 expression was significantly higher in HCC tissues than in paracancerous liver tissues. YTHDF3 was also significantly upregulated in HCC with microvascular invasion (MVI) compared to that in HCC without MVI. YTHDF3 overexpression facilitated the proliferation, invasion, and migration of HCC cells both in vitro and in vivo. However, the YTHDF3 knockdown resulted in an inverse trend. Mechanistically, YTHDF3 enhanced the translation and stability of the m6 A-modified epidermal growth factor receptor (EGFR) mRNA, which activated the downstream EGFR/signal transducer and activator of transcription 3 (STAT3) and epithelial-mesenchymal transition (EMT) oncogenic pathways. YTHDF3 enhanced the stability and translation of m6 A-modified EGFR mRNA and stimulated HCC progression via the YTHDF3/m6 A-EGFR/STAT3 and EMT pathways. These findings reveal that YTHDF3 plays a significant role in regulating HCC progression, suggesting a promising and novel target for HCC treatment.

Partner of NOB1 homolog transcriptionally activated by E2F transcription factor 1 promotes the malignant progression and inhibits ferroptosis of pancreatic cancer

Pancreatic cancer (PC) is one of the deadliest malignancies. Partner of NOB1 homolog (PNO1) has been reported to be involved in tumorigenesis. However, the role of PNO1 in PC remains to be elucidated. The purpose of this study was to examine the effects of PNO1 on the progression of PC and the possible mechanism related to E2F transcription factor 1 (E2F1), a transcription factor predicted by the JASPAR database to bind to the PNO1 promoter region and promoted the proliferation of pancreatic ductal adenocarcinoma. First, PNO1 expression in PC tissues and its association with survival rate were analyzed by the Gene Expression Profiling Interactive Analysis database. Western blot and reverse transcription-quantitative polymerase chain reaction were used to evaluate PNO1 expression in several PC cell lines. After PNO1 silencing, cell proliferation, migration, and invasion were measured by colony formation assay, 5-ethynyl-2'-deoxyuridine staining, wound healing, and transwell assays. Then, the lipid reactive oxygen species in PANC-1 cells was estimated by using C11-BODIPY581/591 probe. The levels of glutathione, malondialdehyde, and iron were measured. The binding between PNO1 and E2F1 was confirmed by luciferase and chromatin immunoprecipitation (ChIP) assays. Subsequently, E2F1 was overexpressed in PANC-1 cells with PNO1 knockdown to perform the rescue experiments. Results revealed that PNO1 was highly expressed in PC tissues and PNO1 expression was positively correlated with overall survival rate and disease-free survival rate. Significantly elevated PNO1 expression was also observed in PC cell lines. PNO1 knockdown inhibited the proliferation, migration, and invasion of PANC-1 cells. Moreover, ferroptosis was promoted in PNO1-silenced PANC-1 cells. Results of luciferase and ChIP assays indicated that E2F1 could bind to PNO1 promoter region. Rescue experiments suggested that E2F1 overexpression reversed the impacts of PNO1 depletion on the malignant behaviors and ferroptosis in PANC-1 cells. Summing up, PNO1 transcriptionally activated by E2F1 promotes the malignant progression and inhibits the ferroptosis of PC.

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.

Study of the antioxidant and anti-pancreatic cancer activities of Anchusa strigosa aqueous extracts obtained by maceration and ultrasonic extraction techniques

Pancreatic cancer is a highly aggressive malignancy and a leading cause of cancer-related deaths worldwide. Moreover, the incidence and mortality rates for pancreatic cancer are projected to keep increasing. A major challenge in the treatment of pancreatic cancer is the lack of effective screening approaches, which contributes to its poor prognosis, indicating the need for new treatment regimens and alternative therapies, such as herbal medicine. The medicinal plant A. strigosa, which is widely distributed in the Eastern Mediterranean region, is a short prickly plant from the Boraginaceae family that has been widely used in traditional medicine for treating various diseases. Nevertheless, its effect on human pancreatic cancer remains poorly investigated. In the present study, we screened the phytochemical content of Anchusa strigosa aqueous extracts obtained by maceration and ultrasound-assisted methods (ASM and ASU, respectively) and evaluated their antioxidant effects. We also investigated their anticancer effects and possible underlying mechanisms. The results show that both extracts were rich in bioactive molecules, with slight differences in their composition. Both extracts exhibited remarkable antioxidant potential and potent radical-scavenging activity in vitro. Additionally, non-cytotoxic concentrations of both extracts attenuated cell proliferation in a time- and concentration-dependent manner, which was associated with a decrease in the proliferation marker Ki67 and an induction of the intrinsic apoptotic pathway. Furthermore, the extracts increased the aggregation of pancreatic cancer cells and reduced their migratory potential, with a concomitant downregulation of integrin β1. Finally, we showed that the ASM extract caused a significant decrease in the levels of COX-2, an enzyme that has been linked to inflammation, carcinogenesis, tumor progression, and metastasis. Taken together, our findings provide evidence that A. strigosa extracts, particularly the extract obtained using the maceration method, have a potential anticancer effect and may represent a new resource for the design of novel drugs against pancreatic cancer.

miR-222-3p-containing macrophage-derived extracellular vesicles confer gemcitabine resistance via TSC1-mediated mTOR/AKT/PI3K pathway in pancreatic cancer

Gemcitabine resistance limits the efficacy of chemotherapy and maintains a challenge for treatment outcomes. Therefore, we aimed to clarify the downstream mechanisms underlying the role of miR-222-3p delivered by M2 macrophage-derived extracellular vesicles (M2 MDEs) in the chemoresistance of pancreatic cancer (PCa). We separated the mouse macrophages and polarized them to M2 phenotypes, from which the EVs were derived. miR-222-3p was highly expressed in M2 MDEs. M2 MDEs were internalized by PCa cells. miR-222-3p overexpressing M2 MDEs were treated with gemcitabine and co-cultured with PCa cells for in vitro experiments. Co-culture with M2 MDEs enriched with miR-222-3p suppressed the sensitivity to gemcitabine, accompanied by diminished apoptosis and promoted proliferation. Furthermore, the M2 MDEs and PCa cells were injected to mice with gemcitabine exposure for in vivo substantiation. The delivery of miR-222-3p inhibitor by M2 MDEs suppressed tumor growth and elevated sensitivity of cancer cells to gemcitabine. Moreover, miR-222-3p was indicated to target and suppress TSC1 expression, while miR-222-3p activated the PI3K/AKT/mTOR pathway. Together, miR-222-3p-containing M2 MDEs enhance chemoresistance in PCa through TSC1 inhibition and activation of the PI3K/AKT/mTOR pathway.

Overcoming EGFR Resistance in Metastatic Colorectal Cancer Using Vitamin C: A Review

Targeted monoclonal antibody therapy against Epidermal Growth Factor Receptor (EGFR) is a leading treatment modality against metastatic colorectal cancer (mCRC). However, with the emergence of KRAS and BRAF mutations, resistance was inevitable. Cells harboring these mutations overexpress Glucose Transporter 1 (GLUT1) and sodium-dependent vitamin C transporter 2 (SVCT2), which enables intracellular vitamin C transport, leading to reactive oxygen species generation and finally cell death. Therefore, high dose vitamin C is proposed to overcome this resistance. A comprehensive search strategy was adopted using Pubmed and MEDLINE databases (up to 11 August 2022). There are not enough randomized clinical trials to support its use in the clinical management of mCRC, except for a subgroup analysis from a phase III study. High dose vitamin C shows a promising role in overcoming EGFR resistance in mCRC with wild KRAS mutation with resistance to anti-epidermal growth factor inhibitors and in patients with KRAS and BRAF mutations.

microRNAs Associated with Gemcitabine Resistance via EMT, TME, and Drug Metabolism in Pancreatic Cancer

Despite extensive research, pancreatic cancer remains a lethal disease with an extremely poor prognosis. The difficulty in early detection and chemoresistance to therapeutic agents are major clinical concerns. To improve prognosis, novel biomarkers, and therapeutic strategies for chemoresistance are urgently needed. microRNAs (miRNAs) play important roles in the development, progression, and metastasis of several cancers. During the last few decades, the association between pancreatic cancer and miRNAs has been extensively elucidated, with several miRNAs found to be correlated with patient prognosis. Moreover, recent evidence has revealed that miRNAs are intimately involved in gemcitabine sensitivity and resistance through epithelial-to-mesenchymal transition, the tumor microenvironment, and drug metabolism. Gemcitabine is the gold standard drug for pancreatic cancer treatment, but gemcitabine resistance develops easily after chemotherapy initiation. Therefore, in this review, we summarize the gemcitabine resistance mechanisms associated with aberrantly expressed miRNAs in pancreatic cancer, especially focusing on the mechanisms associated with epithelial-to-mesenchymal transition, the tumor microenvironment, and metabolism. This novel evidence of gemcitabine resistance will drive further research to elucidate the mechanisms of chemoresistance and improve patient outcomes.

FOLFIRINOX Pharmacodynamic Interactions in 2D and 3D Pancreatic Cancer Cell Cultures

The multi-drug combination regime, FOLFIRINOX, is a standard of care chemotherapeutic therapy for pancreatic cancer patients. However, systematic evaluation of potential pharmacodynamic interactions among multi-drug therapy has not been reported previously. Here, pharmacodynamic interactions of the FOLFIRINOX agents (5-fluorouracil (5-FU), oxaliplatin (Oxa) and SN-38, the active metabolite of irinotecan) were assessed across a panel of primary and established pancreatic cancer cells. Inhibition of cell proliferation was quantified for each drug, alone and in combination, to obtain quantitative, drug-specific interaction parameters and assess the nature of drug interactions. The experimental data were analysed assuming Bliss independent interactions, and nonlinear regression model fitting was conducted in SAS. Estimates of the drug interaction term, psi (ψ), revealed that the Oxa/SN-38 combination appeared synergistic in PANC-1 (ψ = 0.6, 95% CI = 0.4, 0.9) and modestly synergistic, close to additive, in MIAPaCa-2 (ψ = 0.8, 95% CI = 0.6, 1.0) in 2D assays. The triple combination was strongly synergistic in MIAPaCa-2 (ψ = 0.2, 95% CI = 0.1, 0.3) and modestly synergistic/borderline additive in PANC-1 2D (ψ = 0.8, 95% CI = 0.6, 1.0). The triple combination showed antagonistic interactions in the primary PIN-127 and 3D PANC-1 model (ψ > 1). Quantitative pharmacodynamic interactions have not been described for the FOLFIRINOX regimen; this analysis suggests a complex interplay among the three chemotherapeutic agents. Extension of this pharmacodynamic analysis approach to clinical/translational studies of the FOLFIRINOX combination could reveal additional pharmacodynamic interactions and guide further refinement of this regimen to achieve optimal clinical responses.

Epithelial-mesenchymal transition-related long noncoding RNAs in gastric carcinoma

As an evolutionarily phenotypic conversion program, the epithelial-mesenchymal transition (EMT) has been implicated in tumour deterioration and has facilitated the metastatic ability of cancer cells via enhancing migration and invasion. Gastric cancer (GC) remains a frequently diagnosed non-skin malignancy globally. Most GC-associated mortality can be attributed to metastasis. Recent studies have shown that EMT-related long non-coding RNAs (lncRNAs) play a critical role in GC progression and GC cell motility. In addition, lncRNAs are associated with EMT-related transcription factors and signalling pathways. In the present review, we comprehensively described the EMT-inducing lncRNA molecular mechanisms and functional perspectives of EMT-inducing lncRNAs in GC progression. Taken together, the statements of this review provided a clinical implementation in identifying lncRNAs as potential therapeutic targets for advanced GC.

Regulation of temozolomide resistance via lncRNAs: Clinical and biological properties of lncRNAs in gliomas (Review)

Gliomas are a primary types of intracranial malignancies and are characterized by a poor prognosis due to aggressive recurrence profiles. Temozolomide (TMZ) is an auxiliary alkylating agent that is extensively used in conjunction with surgical resection and forms the mainstay of clinical treatment strategies for gliomas. However, the frequent occurrence of TMZ resistance in clinical practice limits its therapeutic efficacy. Accumulating evidence has demonstrated that long non‑coding RNAs (lncRNAs) can play key and varied roles in glioma progression. lncRNAs have been reported to inhibit glioma progression by targeting various signaling pathways. In addition, the differential expression of lncRNAs has also been found to mediate the resistance of glioma to several chemotherapeutic agents, particularly to TMZ. The present review article therefore summarizes the findings of previous studies in an aim to report the significance and function of lncRNAs in regulating the chemoresistance of gliomas. The present review may provide further insight into the clinical treatment of gliomas.

Association between microRNAs and chemoresistance in pancreatic cancer: Current knowledge, new insights, and forthcoming perspectives

Pancreatic duct adenocarcinoma, commonly known as pancreatic cancer (PC), is a cancer-related cause of death due to delayed diagnosis, metastasis, and drug resistance. Patients with PC suffer from incorrect responses to chemotherapy due to inherent and acquired chemical resistance. Numerous studies have shown the mechanism of the effect of chemoresistance on PC, such as genetic and epigenetic changes or the elucidation of signaling pathways. In this regard, microRNAs (miRNAs) have been identified as essential modulators of gene expression in various cellular functions, including chemoresistance. Thus, identifying the underlying link between microRNAs and PC chemoresistance helps determine the exact pathogenesis of PC. This study aims to classify miRNAs and signaling pathways related to PC chemoresistance, suggesting new therapeutic approaches to overcome PC chemoresistance.

Long Non-Coding RNA MIR31HG Promotes the Transforming Growth Factor β-Induced Epithelial-Mesenchymal Transition in Pancreatic Ductal Adenocarcinoma Cells

The epithelial-to-mesenchymal transition (EMT) describes a biological process in which polarized epithelial cells are converted into highly motile mesenchymal cells. It promotes cancer cell dissemination, allowing them to form distal metastases, and also involves drug resistance in metastatic cancers. Transforming growth factor β (TGFβ) is a multifunctional cytokine that plays essential roles in development and carcinogenesis. It is a major inducer of the EMT. The MIR31 host gene (MIR31HG) is a newly identified long non-coding (lnc)RNA that exhibits ambiguous roles in cancer. In this study, a cancer genomics analysis predicted that MIR31HG overexpression was positively correlated with poorer disease-free survival of pancreatic ductal adenocarcinoma (PDAC) patients, which was associated with upregulation of genes related to TGFβ signaling and the EMT. In vitro evidence demonstrated that TGFβ induced MIR31HG expression in PDAC cells, and knockdown of MIR31HG expression reversed TGFβ-induced EMT phenotypes and cancer cell migration. Therefore, MIR31HG has an oncogenic role in PDAC by promoting the EMT.

Secreted HSP90α-LRP1 Signaling Promotes Tumor Metastasis and Chemoresistance in Pancreatic Cancer

The extracellular heat shock protein 90α (eHSP90α) has been reported to promote cancer cell motility. However, whether pancreatic cancer (PC) cells expressed membrane-bound or secreted HSP90α, as well as its underlying mechanism for PC progression, were still unclear. Our study demonstrated that the amounts of secreted HSP90α proteins were discrepant in multiple PC cells. In addition, highly invasive Capan-2 cells have a higher level of secreted HSP90α compared with those of less invasive PL45 cells. The conditioned medium of Capan-2 cells or recombinant HSP90α treatment stimulated the migration and invasion of PC cells, which could be prevented with a neutralizing anti-HSP90α antibody. Furthermore, secreted HSP90α promoted elements of epithelial-mesenchymal transition in PL45 cells, including increases in vimentin and Snail expressions, decreases in E-cadherin expression, and changes in cell shape towards a mesenchymal phenotype, but these phenomena were reversed by the anti-HSP90α antibody in Capan-2 cells. In addition, high levels of low-density lipoprotein receptor-related protein 1 (LRP1) were associated with worsened patient survival in pancreatic adenocarcinoma. We demonstrated LRP1 as a receptor of eHSP90α for its stimulatory role in metastasis, by activating the AKT pathway. In addition, silencing LRP1 enhanced the chemosensitivity to gemcitabine and doxorubicin in Capan-2 cells. Therefore, our study indicated that blocking secreted HSP90α underlies an aspect of metastasis and chemoresistance in PC.

Gemcitabine and XCT790, an ERRα inverse agonist, display a synergistic anticancer effect in pancreatic cancer

Pancreatic cancer (PC) is one of the most fatal and chemoresistant malignancies with a poor prognosis. The current therapeutic options for PC have not achieved satisfactory results due to drug resistance. Therefore, it is urgent to develop novel treatment strategies with enhanced efficacy. This study sought to investigate the anticancer effect of gemcitabine and XCT790, an estrogen-related receptor alpha (ERRα) inverse agonist, as monotherapies or in combination for the treatment of PC. Here we demonstrated that the drug combination synergistically suppressed PC cell viability, its proliferative, migratory, invasive, apoptotic activities, and epithelial-to-mesenchymal transition (EMT), and it triggered G0/G1 cell cycle arrest and programmed cell death in vitro. In addition, in vivo assays using xenograft and mini-PDX (patient-derived xenograft) models further confirmed the synergistic antitumor effect between gemcitabine and XCT790 on PC. Mechanistically, gemcitabine and XCT790 suppressed PC by inhibiting ERRα and MEK/ERK signaling pathway. In conclusion, our current study demonstrated for the first time that gemcitabine combined with XCT790 displayed synergistic anticancer activities against PC, suggesting that their combination might be a promising treatment strategy for the therapy of PC.

Inflammatory cell-derived CXCL3 promotes pancreatic cancer metastasis through a novel myofibroblast-hijacked cancer escape mechanism

OBJECTIVE

Pancreatic ductal adenocarcinoma (PDAC) is the most lethal malignancy and lacks effective treatment. We aimed to understand molecular mechanisms of the intertwined interactions between tumour stromal components in metastasis and to provide a new paradigm for PDAC therapy.

DESIGN

Two unselected cohorts of 154 and 20 patients with PDAC were subjected to correlation between interleukin (IL)-33 and CXCL3 levels and survivals. Unbiased expression profiling, and genetic and pharmacological gain-of-function and loss-of-function approaches were employed to identify molecular signalling in tumour-associated macrophages (TAMs) and myofibroblastic cancer-associated fibroblasts (myoCAFs). The role of the IL-33-ST2-CXCL3-CXCR2 axis in PDAC metastasis was evaluated in three clinically relevant mouse PDAC models.

RESULTS

IL-33 was specifically elevated in human PDACs and positively correlated with tumour inflammation in human patients with PDAC. CXCL3 was highly upregulated in IL-33-stimulated macrophages that were the primary source of CXCL3. CXCL3 was correlated with poor survival in human patients with PDAC. Mechanistically, activation of the IL-33-ST2-MYC pathway attributed to high CXCL3 production. The highest level of CXCL3 was found in PDAC relative to other cancer types and its receptor CXCR2 was almost exclusively expressed in CAFs. Activation of CXCR2 by CXCL3 induced a CAF-to-myoCAF transition and α-smooth muscle actin (α-SMA) was uniquely upregulated by the CXCL3-CXCR2 signalling. Type III collagen was identified as the CXCL3-CXCR2-targeted adhesive molecule responsible for myoCAF-driven PDAC metastasis.

CONCLUSIONS

Our work provides novel mechanistic insights into understanding PDAC metastasis by the TAM-CAF interaction and targeting each of these signalling components would provide an attractive and new paradigm for treating pancreatic cancer.

Help or hindrance: The obesity paradox in cancer treatment response

Obesity is a rising epidemic, the influence of which on cancer development, progression as well as its impact on current standard of care cancer treatments is profound with many facets. Obesity is emerging as a modulating factor in many cancer therapies, such as chemotherapy, radiotherapy, immunotherapy and combination therapies. It has been reported to diminish the efficacy of some treatments but has also been alluded to being protective in terms of reduced treatment toxicities, thus the evolution of the obesity paradox. The obese tumour microenvironment influences treatment response through modulation of a series of aspects, including altered adipocyte secretome, angiogenesis, hypoxia, fibrosis, free fatty acid uptake as well as a modulated immune landscape. However, the influence of these underlying mechanisms on cancer treatment response and the biological action of adipose tissue is still largely unknown. Elucidation of these facets may lead to the enhanced efficacy of current treatment options or the identification of novel methods to combat cancer in the obese tumour microenvironment.

IFIT1 modulates the proliferation, migration and invasion of pancreatic cancer cells via Wnt/β-catenin signaling

OBJECTIVES

Previously, Interferon-induced Protein with Tetratricopeptide Repeats 1 (IFIT1) has been shown to promote cancer development. Here, we aimed to explore the role of IFIT1 in the development and progression of pancreatic cancer, including the underlying mechanisms.

METHODS

We explored IFIT1 expression in pancreatic cancer samples using The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets. Cell Counting Kit-8 (CCK8), colony formation, scratch wound-healing and Transwell assays were performed to assess the proliferation, migration and invasion abilities of pancreatic cancer cells. Gene Set Enrichment Analysis (GSEA) and Western blotting were performed to assess the regulatory effect of IFIT1 on the Wnt/β-catenin pathway.

RESULTS

We found that upregulation of IFIT1 expression is common in pancreatic cancer and is negatively associated with overall patient survival. Knockdown of IFIT1 expression led to decreased proliferation, migration and invasion of pancreatic cancer cells. We also found that IFIT1 could regulate Wnt/β-catenin signaling, and that a Wnt/β-catenin agonist could reverse this effect. In addition, we found that IFIT1 can promote epithelial-mesenchymal transition (EMT) of pancreatic cancer cells.

CONCLUSIONS

Our data indicate that IFIT1 increases pancreatic cancer cell proliferation, migration and invasion by activating the Wnt/β-catenin pathway. In addition, we found that EMT could be regulated by IFIT1. IFIT1 may serve as a potential therapeutic target for pancreatic cancer.

Inhibition of matrix stiffness relating integrin β1 signaling pathway inhibits tumor growth in vitro and in hepatocellular cancer xenografts

Background

Cancer development is strictly correlated to composition and physical properties of the extracellular matrix. Particularly, a higher matrix stiffness has been demonstrated to promote tumor sustained growth. Our purpose was to explore the role of matrix stiffness in liver cancer development.

Methods

The matrix stiffness of tumor tissues was determined by atomic force microscopy (AFM) analysis. In vitro, we used a tunable Polyacrylamide (PA) hydrogels culture system for liver cancer cells culture. The expression level of integrin β1, phosphorylated FAK, ERK1/2, and NF-κB in SMMC-7721 cells was measured by western blotting analysis. We performed MTT, colony formation and transwell assay to examine the tumorigenic and metastatic potential of SMMC-7721 cells cultured on the tunable PA hydrogels. SMMC-7721 cancer xenografts were established to explore the anticancer effects of integrin inhibitors.

Results

Our study provided evidence that liver tumor tissues from metastatic patients possessed a higher matrix stiffness, when compared to the non-metastatic group. Liver cancer cells cultured on high stiffness PA hydrogels displayed enhanced tumorigenic potential and migrative properties. Mechanistically, activation of integrin β1/FAK/ ERK1/2/NF-κB signaling pathway was observed in SMMC-7721 cells cultured on high stiffness PA hydrogels. Inhibition of ERK1/2, FAK, and NF-κB signaling suppressed the pro-tumor effects induced by matrix stiffness. Combination of chemotherapy and integrin β1 inhibitor suppressed the tumor growth and prolonged survival time in hepatocellular cancer xenografts.

Conclusion

A higher matrix stiffness equipped tumor cells with enhanced stemness and proliferative characteristics, which was dependent on the activation of integrin β1/FAK/ERK1/2/NF-κB signaling pathway. Blockade of integrin signals efficiently improved the outcome of chemotherapy, which described an innovative approach for liver cancer treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08982-3.

AXL inhibitor TP-0903 reduces metastasis and therapy resistance in pancreatic cancer

Pancreatic cancer is the 3rd leading cause of cancer-related deaths in the United States with a 5-year survival less than 5%. Resistance to standard therapy and limited response to immune checkpoint blockade due to the immunosuppressive and stroma-rich microenvironment remain major challenges in the treatment of pancreatic cancer. A key cellular program involved in therapy resistance is epithelial plasticity, which is also associated with invasion, metastasis, and evasion of immune surveillance. The receptor tyrosine kinase AXL is a key driver of tumor cell epithelial plasticity. High expression and activity of AXL is associated with poor prognosis, metastasis, and therapy resistance in multiple types of cancer including pancreatic. Here, we show that an AXL inhibitor (TP-0903), has anti-tumor and therapy sensitizing effects in pre-clinical models of pancreatic ductal adenocarcinoma (PDA). We demonstrate that TP-0903 as a single agent or in combination with gemcitabine and/or anti-programmed cell death protein 1 (PD1) antibody has anti-metastatic and anti-tumor effects in PDA tumor bearing mice, leading to increased survival. Additionally, gene expression analysis of tumors demonstrated upregulation of pro-inflammatory and immune activation genes in tumors from TP-0903-treated animals compared to the vehicle, indicating pharmacologic inhibition of AXL activation leads to an immunostimulatory microenvironment. This effect was augmented when TP-0903 was combined with gemcitabine and anti-PD1 antibody. These results provide clear rationale for evaluating TP-0903 in the treatment of pancreatic cancer.

Adjuvant Treatment in Pancreatic Cancer: Shaping the Future of the Curative Setting

Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease even in the early stages, despite progresses in surgical and pharmacological treatment in recent years. High potential for metastases is the main cause of therapeutic failure in localized disease, highlighting the current limited knowledge of underlying pathological processes. However, nowadays research is focusing on the search for personalized approaches also in the adjuvant setting for PDAC, by implementing the use of biomarkers and investigating new therapeutic targets. In this context, the aim of this narrative review is to summarize the current treatment scenario and new potential therapeutic approaches in early stage PDAC, from both a preclinical and clinical point of view. Additionally, the review examines the role of target therapies in localized PDAC and the influence of neoadjuvant treatments on survival outcomes.

Sauchinone inhibits hypoxia-induced epithelial-mesenchymal transition in pancreatic ductal adenocarcinoma cells through the Wnt/β-catenin pathway

The hypoxic microenvironment is commonly found in various solid tumors including pancreatic ductal adenocarcinoma (PDAC). Saururus chinensis is a medicinal Chinese herb widely used because of documented anti-inflammatory and anti-angiogenic properties. Sauchinone is special active lignin extracted from S. chinensis and its biological functions have been extensively explored. Recent studies have found that sauchinone could affect tumor initiation, metastasis and progression of some cancers. However, the specific role of sauchinone in PDAC remains to be elucidated. The main aim of this study was to elucidate the involvement of sauchinone in the progression of PDAC under the hypoxic condition. The human PDAC cell lines PANC-1 and BxPC-3 were exposed to hypoxia and various concentrations of sauchinone. The CCK-8 assay was performed to detect cytotoxic effects of sauchinone on PDAC cells. The levels of vascular endothelial growth factor, hypoxia-inducible factor-1α, E-cadherin, N-cadherin, Wnt3a and β-catenin were examined by the western blot analysis. Wound healing and transwell assays were used to assess cell migration and invasion. The results showed that the migratory and invasive abilities of PDAC cells were enhanced after exposure to hypoxia and the expression of epithelial-mesenchymal transition markers was also significantly regulated by hypoxia. All these effects induced under the hypoxic condition were terminated by sauchinone treatment. In addition, sauchinone suppressed hypoxia-induced activation of the Wnt/β-catenin signaling pathway. Our study provided important insight into understanding the mechanisms of the anti-cancer effect of sauchinone. Taken together, we suggested that sauchinone may be considered a new therapeutic agent for PDAC treatment.

Microorganisms in chemotherapy for pancreatic cancer: An overview of current research and future directions

Pancreatic cancer is a malignant tumor of the digestive system with a very high mortality rate. While gemcitabine-based chemotherapy is the predominant treatment for terminal pancreatic cancer, its therapeutic effect is not satisfactory. Recently, many studies have found that microorganisms not only play a consequential role in the occurrence and progression of pancreatic cancer but also modulate the effect of chemotherapy to some extent. Moreover, microorganisms may become an important biomarker for predicting pancreatic carcinogenesis and detecting the prognosis of pancreatic cancer. However, the existing experimental literature is not sufficient or convincing. Therefore, further exploration and experiments are imperative to understanding the mechanism underlying the interaction between microorganisms and pancreatic cancer. In this review, we primarily summarize and discuss the influences of oncolytic viruses and bacteria on pancreatic cancer chemotherapy because these are the two types of microorganisms that are most often studied. We focus on some potential methods specific to these two types of microorganisms that can be used to improve the efficacy of chemotherapy in pancreatic cancer therapy.

Stabilized epithelial phenotype of cancer cells in primary tumors leads to increased colonization of liver metastasis in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is therapeutically recalcitrant and metastatic. Partial epithelial to mesenchymal transition (EMT) is associated with metastasis; however, a causal connection needs further unraveling. Here, we use single-cell RNA sequencing and genetic mouse models to identify the functional roles of partial EMT and epithelial stabilization in PDAC growth and metastasis. A global EMT expression signature identifies ∼50 cancer cell clusters spanning the epithelial-mesenchymal continuum in both human and murine PDACs. The combined genetic suppression of Snail and Twist results in PDAC epithelial stabilization and increased liver metastasis. Genetic deletion of Zeb1 in PDAC cells also leads to liver metastasis associated with cancer cell epithelial stabilization. We demonstrate that epithelial stabilization leads to the enhanced collective migration of cancer cells and modulation of the immune microenvironment, which likely contribute to efficient liver colonization. Our study provides insights into the diverse mechanisms of metastasis in pancreatic cancer and potential therapeutic targets.

Clinical relevance of CD70 expression in resected pancreatic cancer: Prognostic value and therapeutic potential

BACKGROUND

Aberrant expression of CD70 in several malignancies is potentially associated with poor patient prognosis and could serve as a therapeutic target. However, the clinical relevance of CD70 expression in pancreatic cancer has not been thoroughly explored.

METHODS

We evaluated CD70 expression in 166 surgical specimens obtained from human patients with pancreatic cancer. We analyzed the function of CD70 in proliferation and migration using pancreatic cancer cell lines with silenced CD70 expression.

RESULTS

CD70 expression was positively stained in 42 patients (25%). In the whole cohort, high CD70 expression was not associated with overall survival (OS: 33.1 vs. 40.8 months, P = 0.256), although it was significantly associated with inferior OS in a population of patients that completed adjuvant chemotherapy (OS: 45.4 vs. 63.8 months, P = 0.027). Moreover, the incidence of hematogenous metastasis was significantly higher in patients with high CD70 expression than in those with low CD70 expression (P = 0.020). This finding was also statistically significant in multivariate analyses (P = 0.001). In vitro experiments demonstrated that CD70 expression contributed to cancer cell proliferation independently of gemcitabine treatment as well as cell migration. Furthermore, real-time polymerase chain reaction analysis of frozen surgical tissues showed a correlation between the expression of CD70 and mesenchymal markers.

CONCLUSIONS

CD70 expression in pancreatic cancer might be involved in hematogenous metastasis. Furthermore, our results imply that CD70 overexpression can serve as a novel prognostic factor and a potential therapeutic target in patients who have completed adjuvant chemotherapy.

Noncoding RNAs Associated with Therapeutic Resistance in Pancreatic Cancer

Therapeutic resistance is an inevitable impediment towards effective cancer therapies. Evidence accumulated has shown that the signaling pathways and related factors are fundamentally responsible for therapeutic resistance via regulating diverse cellular events, such as epithelial-to-mesenchymal transition (EMT), stemness, cell survival/apoptosis, autophagy, etcetera. Noncoding RNAs (ncRNAs) have been identified as essential cellular components in gene regulation. The expression of ncRNAs is altered in cancer, and dysregulated ncRNAs participate in gene regulatory networks in pathological contexts. An in-depth understanding of molecular mechanisms underlying the modulation of therapeutic resistance is required to refine therapeutic benefits. This review presents an overview of the recent evidence concerning the role of human ncRNAs in therapeutic resistance, together with the feasibility of ncRNAs as therapeutic targets in pancreatic cancer.

Integrin α7 knockdown suppresses cell proliferation, migration, invasion and EMT in hepatocellular carcinoma

The present study aimed to investigate the effects of integrin α7 (ITGA7) on regulating hepatocellular carcinoma (HCC) progression and endothelial-mesenchymal transition (EMT). ITGA7 mRNA and protein expression in human normal liver epithelial cells and HCC cell lines were determined by reverse transcription-quantitative PCR (RT-qPCR) and western blotting. ITGA7 small interfering RNA [siRNA; ITGA7-knockdown (KD) group] and nonsense siRNA (control group) were transfected into Huh7 cells and SNU449 cells, respectively. ITGA7 mRNA and protein expression (RT-qPCR and western blotting, respectively), cell proliferation (Cell Counting Kit-8 assay), apoptosis (annexin V/propidium iodide assay), migration (wound scratch assay) and invasion (Transwell assay) were then detetected. E-cadherin, α-smooth muscle actin (α-SMA), vimentin and V-cadherin levels (RT-qPCR and western blotting) were also assessed. ITGA7 mRNA and protein expression levels were increased in Li7, Huh7, SKHEP1 and SNU449 cells compared with THLE-3 cells. Following transfection, ITGA7 mRNA and protein expression was lower in the ITGA7-KD group compared with that in the control group in both Huh7 and SNU449 cells, indicating successful transfection. In the ITGA7-KD group, cell proliferation decreased at 48 and 72 h, cell apoptosis rates increased at 48 h, cell migration rate was reduced at 24 h and cell invasion decreased at 24 h compared with the control group. Additionally, increased E-cadherin but decreased α-SMA, vimentin and V-cadherin mRNA and protein expression levels were observed in the ITGA7-KD group compared with the control group at 24 h. In conclusion, ITGA7 knockdown suppressed HCC progression and inhibited EMT in HCC in vitro, implying that ITGA7 might be a novel treatment target for HCC.

Hypoxia-induced lncRNA CASC9 enhances glycolysis and the epithelial-mesenchymal transition of pancreatic cancer by a positive feedback loop with AKT/HIF-1α signaling

Increasing evidence indicates the dysregulations and pivotal roles of lncRNAs in the development and progression of various cancers, including pancreatic cancer. Enhanced glycolytic flux and epithelial-to-mesenchymal transition (EMT) have been considered as important factors in driving the malignance of pancreatic cancer. Here, we sought to evaluate the biological role and involved mechanism of lncRNA CASC9 (CASC9) in pancreatic cancer. Our present study showed that CASC9 was upregulated in various pancreatic cancer cell lines. Loss- and gain-of function of CASC9 demonstrated its critical roles in promoting the glycolysis and EMT phenotypes of pancreatic cancer. Moreover, knockdown of CASC9 inhibited the tumorigenicity and metastasis in vivo. Additionally, our findings showed that hypoxia induced the expression of CASC9 and enhanced the binding of HIF-1α to its promoter. We also demonstrated that the positive feedback loop of CASC9 and the AKT/HIF-1α signaling cascade partially mediated this biological process. Altogether, our results suggest that CASC9 promotes the glycolysis and EMT of pancreatic cancer by a positive feedback loop with AKT/HIF-1α signaling, which is synergistically enhanced by the tumor hypoxic niche. Our study will provide potential therapeutic targets for treating pancreatic cancer.

Early macrophage infiltrates impair pancreatic cancer cell growth by TNF-α secretion

Background

Pancreatic ductal adenocarcinoma (PDAC) is a grim disease with high mortality rates. Increased macrophage influx in PDAC is a common hallmark and associated with poor prognosis. Macrophages have high cellular plasticity, which can differentiate into both anti- and pro-tumorigenic properties. Here, we investigated how naïve (M0) macrophages differ from other macrophages in their anti-tumorigenic activities.

Methods

In vitro BrdU proliferation and Annexin V cell death analyses were performed on PANC-1 and MIA PaCa-2 PDAC cell lines exposed to conditioned medium of different macrophage subsets. Macrophage secreted factors were measured by transcript analysis and ELISA. Therapeutic antibodies were used to functionally establish the impact of the identified cytokine on PDAC proliferation.

Results

Proliferation and cell death assays revealed that only M0 macrophages harbor anti-tumorigenic activities and that M1, M2, and TAMs do not. mRNA analysis and ELISA results suggested TNF-α as a potential candidate to mediate M0 macrophage induced cell death. To demonstrate the importance of TNF-α in M0 macrophage-induced cell death, PANC-1 and MIA PaCa-2 cell-lines were exposed to M0 macrophage conditioned medium in the presence of the TNF-α inhibitor Infliximab, which effectively diminished the anti-tumor activities of M0 macrophages.

Conclusion

Newly tumor-infiltrated naive M0 macrophages exert anti-tumorigenic activities via TNF-α secretion. Their subsequent differentiation into either M1, M2, or TAM subsets reduces TNF-α levels, thereby abolishing their cytotoxic activity on PDAC cells. These data suggest that reestablishing TNF-α secretion in differentiated macrophages might yield a therapeutic benefit.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-020-07697-1.

HOX Genes Family and Cancer: A Novel Role for Homeobox B9 in the Resistance to Anti-Angiogenic Therapies

Simple Summary

The inhibition of angiogenesis, relying on the use of drugs targeting the VEGF signaling pathway, has become one of the main strategies for cancer treatment. However, the intrinsic and acquired resistance to this type of therapy limit its efficacy. Thus, the identification of novel therapeutic targets is urgently needed. The resistance to anti-angiogenic treatment often occurs through the activation of alternative VEGF independent signaling pathways and recruitment of bone marrow-derived pro-angiogenic cells in the tumor microenvironment. HOX genes are key regulators of embryonic development, also involved in angiogenesis and in cancer progression. HOXB9 upregulation occurs in many types of cancer and it has been identified as a critical transcription factor involved in tumour resistance to anti-angiogenic drugs. Indeed, HOXB9 modulates the expression of alternative pro-angiogenic secreted factors in the tumour microenvironment leading tumor escape from the anti-angiogenic treatments. Hence, HOXB9 could serves as a novel therapeutic target to overcome the resistance to anti-angiogenic therapies.

Abstract

Angiogenesis is one of the hallmarks of cancer, and the inhibition of pro-angiogenic factors and or their receptors has become a primary strategy for cancer therapy. However, despite promising results in preclinical studies, the majority of patients either do not respond to these treatments or, after an initial period of response, they develop resistance to anti-angiogenic agents. Thus, the identification of a novel therapeutic target is urgently needed. Multiple mechanisms of resistance to anti-angiogenic therapy have been identified, including the upregulation of alternative angiogenic pathways and the recruitment of pro-angiogenic myeloid cells in the tumor microenvironment. Homeobox containing (HOX) genes are master regulators of embryonic development playing a pivotal role during both embryonic vasculogenesis and pathological angiogenesis in adults. The importance of HOX genes during cancer progression has been reported in many studies. In this review we will give a brief description of the HOX genes and their involvement in angiogenesis and cancer, with particular emphasis on HOXB9 as a possible novel target for anti-angiogenic therapy. HOXB9 upregulation has been reported in many types of cancers and it has been identified as a critical transcription factor involved in resistance to anti-angiogenic drugs.

Bergenin inhibits bladder cancer progression via activating the PPARγ/PTEN/Akt signal pathway

Bladder cancer is one of the most common malignant tumors in the urinary system with high mortality and morbidity. Evidence revealed that bergenin could affect the development of cancer. Here, we aimed to investigate the effect of bergenin on bladder cancer progression and its mechanism. The effect of bergenin on cell function was first detected, followed by assessing the changes of the epithelial-mesenchymal transition (EMT) in bergenin-treated cells. The effect of bergenin on peroxisome proliferator-activated receptor γ (PPARγ)/phosphatase and tensin homolog (PTEN)/Akt signal pathway was measured by Western blotting, followed by the rescue experiments. The results showed that bergenin treatment significantly decreased cell viability and increased G1 phase arrest, accompanied by reduced expression of Ki67, cycling D1, and cycling B1 in bladder cancer cells. Apoptosis was induced by bergenin in bladder cancer cells, as evidenced by increased Bax and cleaved caspase 3 protein levels and decreased Bcl-2 level in bergenin-treated cells. Meanwhile, the inhibition of the invasion, migration, and EMT was also observed in bergenin-treated cells. Mechanism studies showed that bergenin treatment could activate PPARγ/PTEN/Akt signal pathway, as evidence by the increased nucleus PPARγ and phosphatase and tensin homolog (PTEN) expression and decreased Akt expression. Moreover, PPARγ inhibitor administration inverted the effects of bergenin on bladder cancer cell function, including the proliferation, apoptosis, invasion, and migration in bladder cancer cells. Our findings revealed that bergenin could inhibit bladder cancer progression via activating the PPARγ/PTEN/Akt signal pathway, indicating that bergenin may be a potential therapeutic medicine for bladder cancer treatment.

Metformin Increases the Chemosensitivity of Pancreatic Cancer Cells to Gemcitabine by Reversing EMT Through Regulation DNA Methylation of miR-663

Background

Pancreatic cancer is a devastating malignancy with poor prognosis. Metformin, a classic anti-diabetes drug, seems to improve survival of pancreatic cancer patients in some studies.

Methods

Cell counting kit-8 assay was used to detect the BxPC-3 and MIAPaCa-2 cell viability after treatment with gemcitabine only or with different concentrations of metformin. The methylation state and expression level of miR-663 were detected by methylation analysis and RT-PCR. Dual-luciferase reporter gene analysis, Western blot and RT-PCR were used to confirm the target of miR-663. Moreover, xenograft experiment was also performed to validate the role of metformin in chemosensitivity in vivo.

Results

We found that metformin increased the chemosensitivity of pancreatic cancer cells to gemcitabine, and epithelial-mesenchymal transition (EMT) progress caused by gemcitabine was suppressed by metformin. We further explored the possible molecular mechanisms and it was demonstrated that CpG islands of miR-663 were hypomethylated and relative expression level of miR-663 was up-regulated after treatment of metformin. miR-663, an important cancer suppressor miRNA, was confirmed to increase the chemosensitivity of pancreatic cancer cells by reversing EMT directly targeted TGF-β1. Moreover, we identified that metformin increased the chemosensitivity through up-regulating expression of miR-663.

Conclusion

We demonstrated that metformin increased the chemosensitivity of pancreatic cancer cells to gemcitabine by reversing EMT through regulation DNA methylation of miR-663.

Antiproliferative and Antimigration Activities of Beauvericin Isolated from Isaria sp. on Pancreatic Cancer Cells

This study describes the antiproliferative and antimigration effects of beauvericin from a culture broth of Isaria sp. in human pancreatic cancer cells (PANC-1). Activity-guided fractionation of the EtOAc extract of cultured broth of Isaria sp. RD055140 afforded beauvericin (1), a new isariotin derivative, 7-O-methylisariotin C (2), together with the known isariotin analogs, TK-57-164A (3) and B (4). As a result of the measurement of the cell viability, 1 inhibited cell growth (IC50 = 4.8 µM) of PANC-1 cells. Furthermore, 1 was found to inhibit the migration activity of PANC-1 cells by upregulating the expression of the E-cadherin gene and reducing N-cadherin and Snail genes in a dose-dependent manner (0.1-1 µM). These activities of 1 had lower concentrations than the cytotoxic activity. These findings suggest that 1 can be used as an anticancer agent against human pancreatic carcinoma.

Single-cell transcriptome analysis of tumor and stromal compartments of pancreatic ductal adenocarcinoma primary tumors and metastatic lesions

BACKGROUND

Solid tumors such as pancreatic ductal adenocarcinoma (PDAC) comprise not just tumor cells but also a microenvironment with which the tumor cells constantly interact. Detailed characterization of the cellular composition of the tumor microenvironment is critical to the understanding of the disease and treatment of the patient. Single-cell transcriptomics has been used to study the cellular composition of different solid tumor types including PDAC. However, almost all of those studies used primary tumor tissues.

METHODS

In this study, we employed a single-cell RNA sequencing technology to profile the transcriptomes of individual cells from dissociated primary tumors or metastatic biopsies obtained from patients with PDAC. Unsupervised clustering analysis as well as a new supervised classification algorithm, SuperCT, was used to identify the different cell types within the tumor tissues. The expression signatures of the different cell types were then compared between primary tumors and metastatic biopsies. The expressions of the cell type-specific signature genes were also correlated with patient survival using public datasets.

RESULTS

Our single-cell RNA sequencing analysis revealed distinct cell types in primary and metastatic PDAC tissues including tumor cells, endothelial cells, cancer-associated fibroblasts (CAFs), and immune cells. The cancer cells showed high inter-patient heterogeneity, whereas the stromal cells were more homogenous across patients. Immune infiltration varies significantly from patient to patient with majority of the immune cells being macrophages and exhausted lymphocytes. We found that the tumor cellular composition was an important factor in defining the PDAC subtypes. Furthermore, the expression levels of cell type-specific markers for EMT+ cancer cells, activated CAFs, and endothelial cells significantly associated with patient survival.

CONCLUSIONS

Taken together, our work identifies significant heterogeneity in cellular compositions of PDAC tumors and between primary tumors and metastatic lesions. Furthermore, the cellular composition was an important factor in defining PDAC subtypes and significantly correlated with patient outcome. These findings provide valuable insights on the PDAC microenvironment and could potentially inform the management of PDAC patients.

Reprogramming of Amino Acid Metabolism in Pancreatic Cancer: Recent Advances and Therapeutic Strategies

Pancreatic ductal adenocarcinoma (PDAC) is one of the most fatal malignancies with an extremely poor prognosis. Energy metabolism reprogramming, an emerging hallmark of cancer, has been implicated in the tumorigenesis and development of pancreatic cancer. In addition to well-elaborated enhanced glycolysis, investigating the role of reprogramming of amino acid metabolism has sparked great interests in recent years. The rewiring amino acid metabolism orchestrated by genetic alterations contributes to pancreatic cancer malignant characteristics including cell proliferation, invasion, metastasis, angiogenesis and redox balance. In the unique hypoperfused and nutrient-deficient tumor microenvironment (TME), the interactions between cancer cells and stromal components and salvaging processes including autophagy and macropinocytosis play critical roles in fulfilling the metabolic requirements and supporting growth of PDAC. In this review, we elucidate the recent advances in the amino acid metabolism reprogramming in pancreatic cancer and the mechanisms of amino acid metabolism regulating PDAC progression, which will provide opportunities to develop promising therapeutic strategies.

TET1 downregulates epithelial-mesenchymal transition and chemoresistance in PDAC by demethylating CHL1 to inhibit the Hedgehog signaling pathway

Chemoresistance is a major obstacle to prolonging pancreatic ductal adenocarcinoma (PDAC) patient survival. TET1 is identified as the most important epigenetic modification enzyme that facilitates chemoresistance in cancers. However, the chemoresistance mechanism of TET1 in PDAC is unknown. This study aimed to determine the role of TET1 in the chemoresistance of PDAC. TET1-associated chemoresistance in PDAC was investigated in vitro and in vivo. The clinical significance of TET1 was analyzed in 228 PDAC patients by tissue microarray profiling. We identified that TET1 downregulation is caused by its promoter hypermethylation and correlates with poor survival in PDAC patients. In vitro and in vivo functional studies performed by silencing or overexpressing TET1 suggested that TET1 is able to suppress epithelial-mesenchymal transition (EMT) and sensitize PDAC cells to 5FU and gemcitabine. Then RNA-seq, whole genome bisulfite sequencing (WGBS) and ChIP-seq were used to explore the TET1-associated pathway, and showed that TET1 promotes the transcription of CHL1 by binding and demethylating the CHL1 promoter, which consequently inhibits the Hedgehog pathway. Additionally, inhibiting Hedgehog signaling by CHL1 overexpression or the Hedgehog pathway inhibitor, GDC-0449, reversed the chemoresistance induced by TET1 silencing. Regarding clinical significance, we found that high TET1 and high CHL1 expression predicted a better prognosis in resectable PDAC patients. In summary, we demonstrated that TET1 reverses chemoresistance in PDAC by downregulating the CHL1-associated Hedgehog signaling pathway. PDAC patients with a high expression levels of TET1 and CHL1 have a better prognosis.

CPA4 Promotes EMT in Pancreatic Cancer via Stimulating PI3K-AKT-mTOR Signaling

Background

Carboxypeptidase A4 (CPA4), as a novel tumor biomarker, is prevalently observed in various cancers. However, the potential role of CPA4 in pancreatic cancer (PC), to our knowledge, has not been fully clarified.

Materials and Methods

We systematically explored the detailed function of CPA4 in epithelial to mesenchymal transition (EMT) stimulated PC in human clinical samples and in vitro.

Results

CPA4 was overexpressed in clinical PC samples that was positively related with tumor size (P=0.026), T stage (P=0.011), lymph-node metastasis (P=0.026) and a worse prognosis for PC patients (P=0.001). Interestingly, CPA4 was inversely correlated with E-cadherin (r=−0.372, P=0.003) in clinical samples and PC cell lines which cooperatively contributed to a worse prognosis (P=0.005) for PC patients. CPA4 overexpression enhanced EMT in AsPC-1 and Capan-2 cells, which promoted EMT-like cellular morphology and cell invasion and migration. Meanwhile, CPA4 overexpression activated EMT and PI3K-AKT-mTOR signaling, following with the downregulation of E-cadherin and β-catenin, and the upregulation of N-cadherin, vimentin, p-PI3K (Tyr458), p-AKT (Ser473) and p-mTOR (Ser2448). However, PI3K inhibitor LY294002 reversed CPA4 overexpression-stimulated EMT in vitro. Moreover, CPA4 was co-immunoprecipitated with AKT in two PC cells with CPA4 high expression. Conversely, CPA4 silencing inhibited EMT in PANC-1 cells. CPA4 overexpression or silencing promoted or inhibited cell proliferation and drug resistance in Capan-2 and PANC-1 cells via regulating Bcl2/Bax and cleaved-caspase3 signaling. However, LY294002 reversed CPA4 overexpression-stimulated cell proliferation and drug resistance in vitro in Bcl2/Bax and caspase3-dependent apoptosis.

Conclusion

CPA4 overexpression contributes to aggressive clinical stage of PC patients and promotes EMT in vitro via activation of PI3K-AKT-mTOR signaling.

circ_KIAA1429 accelerates hepatocellular carcinoma advancement through the mechanism of m6A-YTHDF3-Zeb1

AIMS

Hepatocellular carcinoma (HCC), one of the most common cancer, causes the fourth cancer-related deaths around the world. N6-methyladenosine (m⁶A) has been reported to mediate circRNA translation in cancer biology. However, the mechanisms by which m⁶A and circRNA in post-transcriptional in HCC progression remain poorly understood. This study aimed to explore the mechanisms by which m⁶A and circRNA in post-transcriptional in HCC progression.

MAIN METHODS

circ_KIAA1429 (hsa_circ_0084922) expression profiles in matched normal and HCC tissues were detected using microarray analysis. The biological roles of circ_KIAA1429 in progression of HCCC were measured both in vitro and in vivo.

KEY FINDINGS

In this study, we found hsa_circ_0084922, which came from KIAA1429, named circ_KIAA1429, was upregulated in HCC cells and tumor tissues. Overexpression of circ_KIAA1429 can facilitate HCC migration, invasion, and EMT process. However, knockdown of circ_KIAA1429 lead to the opposite results. Furthermore, it was demonstrated that Zeb1 was the downstream target of circ_KIAA1429. Up-regulation of Zeb1 led to HCC cells metastasis induced by circ_KIAA1429. In addition, YTHDF3 enhanced Zeb1 mRNA stability via an m⁶A dependent manner.

SIGNIFICANCE

This study revealed that circ_KIAA1429 could accelerate HCC advancement, maintained the expression of Zeb1 through the mechanism of m⁶A-YTHDF3-Zeb1 in HCC. What's more, it might represent a potential therapeutic target in HCC.