Targeting apoptosis pathways in pancreatic cancer

Using microRNAs Networks to Understand Pancreatic Cancer-A Literature Review

Pancreatic cancer is a severe disease, challenging to diagnose and treat, and thereby characterized by a poor prognosis and a high mortality rate. Pancreatic ductal adenocarcinoma (PDAC) represents approximately 90% of pancreatic cancer cases, while other cases include neuroendocrine carcinoma. Despite the growing knowledge of the pathophysiology of this cancer, the mortality rate caused by it has not been effectively reduced. Recently, microRNAs have aroused great interest among scientists and clinicians, as they are negative regulators of gene expression, which participate in many processes, including those related to the development of pancreatic cancer. The aim of this review is to show how microRNAs (miRNAs) affect key signaling pathways and related cellular processes in pancreatic cancer development, progression, diagnosis and treatment. We included the results of in vitro studies, animal model of pancreatic cancer and those performed on blood, saliva and tumor tissue isolated from patients suffering from PDAC. Our investigation identified numerous dysregulated miRNAs involved in KRAS, JAK/STAT, PI3/AKT, Wnt/β-catenin and TGF-β signaling pathways participating in cell cycle control, proliferation, differentiation, apoptosis and metastasis. Moreover, some miRNAs (miRNA-23a, miRNA-24, miRNA-29c, miRNA-216a) seem to be engaged in a crosstalk between signaling pathways. Evidence concerning the utility of microRNAs in the diagnosis and therapy of this cancer is poor. Therefore, despite growing knowledge of the involvement of miRNAs in several processes associated with pancreatic cancer, we are beginning to recognize and understand their role and usefulness in clinical practice.

miR-107 reverses the multidrug resistance of gastric cancer by targeting the CGA/EGFR/GATA2 positive feedback circuit

Chemotherapy is still the main therapeutic strategy for gastric cancer (GC). However, most patients eventually acquire multidrug resistance (MDR). Hyperactivation of the EGFR signaling pathway contributes to MDR by promoting cancer cell proliferation and inhibiting apoptosis. We previously identified the secreted protein CGA as a novel ligand of EGFR and revealed a CGA/EGFR/GATA2 positive feedback circuit that confers MDR in GC. Herein, we outline a microRNA-based treatment approach for MDR reversal that targets both CGA and GATA2. We observed increased expression of CGA and GATA2 and increased activation of EGFR in GC samples. Bioinformatic analysis revealed that miR-107 could simultaneously target CGA and GATA2, and the low expression of miR-107 was correlated with poor prognosis in GC patients. The direct interactions between miR-107 and CGA or GATA2 were validated by luciferase reporter assays and Western blot analysis. Overexpression of miR-107 in MDR GC cells increased their susceptibility to chemotherapeutic agents, including fluorouracil, adriamycin, and vincristine, in vitro. Notably, intratumor injection of the miR-107 prodrug enhanced MDR xenograft sensitivity to chemotherapies in vivo. Molecularly, targeting CGA and GATA2 with miR-107 inhibited EGFR downstream signaling, as evidenced by the reduced phosphorylation of ERK and AKT. These results suggest that miR-107 may contribute to the development of a promising therapeutic approach for the treatment of MDR in GC.

A Ferroptosis-Inducing Arsenene-Iridium Nanoplatform for Synergistic Immunotherapy in Pancreatic Cancer

Due to multidrug resistance and the high risk of recurrence, effective and less toxic alternative pancreatic cancer treatments are urgently needed. Pancreatic cancer cells are highly resistant to apoptosis but sensitive to ferroptosis. In this study, an innovative nanoplatform (AsIr@PDA) was developed by electrostatic adsorption of a cationic iridium complex (IrFN) onto two-dimensional (2D) arsenene nanosheets. This nanoplatform exhibits superior ferroptosis-inducing effects with high drug loading capacity and, importantly, excellent anti-cancer immune activation function, leading to efficient elimination of pancreatic tumors with no observable side effects. Interestingly, AsIr@PDA significantly prevents the recurrence of pancreatic cancer in vivo when compared with a cisplatin-loaded nanoplatform. This designed nanoplatform demonstrated superior therapeutic efficacy by synergistic ferroptosis-induced chemotherapy with immunotherapy via an all-in-one strategy, providing new insights for future pancreatic cancer therapy.

Clusterin is upregulated by erastin, a ferroptosis inducer and exerts cytoprotective effects in pancreatic adenocarcinoma cells

Ferroptosis is a novel form of cell death, which is distinguished from apoptosis and necrosis, and characterized by accumulation of lipid-based reactive oxygen species (ROS) in an iron-dependent manner. Erastin, a small molecule, was widely reported to trigger ferroptosis in various kinds of cancer cells, including pancreatic cancer cells by inducing ROS accumulation. However, how erastin treatment exerts cytotoxicity is not still fully understood. In this study, the effects of erastin in causing pancreatic cancer cell death via inducing ferroptosis and apoptosis are investigated. As expected, erastin treatment caused ROS accumulation, increase in iron concentration and non-apoptotic cell death, which is different from that of induced by apoptosis inducer, staurosporine. Interestingly, erastin treatment caused the upregulation of clusterin, which contributes to the regulation of malignant behaviors of pancreatic cancer, including preventing apoptosis and inducing chemoresistance. Without erastin treatment, overexpressed clusterin significantly promoted cell proliferation, which is consistent with its cytoprotective roles. After erastin treatment, overexpressed clusterin decreased erastin-induced ROS accumulation and cell death. By measuring iron concentration, reduced glutathione (GSH) and glutathione peroxidase 4 (GPX4), it is revealed that clusterin caused resistance to erastin-induced ferroptosis potentially via maintaining the enzymatic activity of GPX4, without disturbing GSH amount. Thus, ferroptosis inducer, erastin, may crosstalk with apoptotic cell death via regulating clusterin, indicating a more complex regulatory network between ferroptosis and apoptosis.

A prognostic and immunotherapy effectiveness model for pancreatic adenocarcinoma based on cuproptosis-related lncRNAs signature

Pancreatic adenocarcinoma (PAAD) results in one of the deadliest solid tumors with discouraging clinical outcomes. Growing evidence suggests that long non-coding RNAs (lncRNAs) play a crucial role in altering the growth, prognosis, migration, and invasion of pancreatic cancer cells. Cuproptosis is a novel type of cell death induced by copper (Cu) and is associated with mitochondrial respiration during the tricarboxylic acid cycle. However, the relationship between lncRNAs related to cuproptosis and PAAD is poorly studied. In this study, we investigated the association between a signature of cuproptosis-related lncRNAs and the diagnosis of PAAD. Genomic data and clinical information were obtained using the TCGA dataset, while cuproptosis-related genes (CRGs) from previous studies. Co-expression analysis was utilized to identify lncRNAs associated with cuproptosis. We developed and verified a prognostic risk model following a classification of patients into high- and low-risk categories. The prediction capacity of the risk model was assessed using a number of methods including Kaplan-Meier analysis, receiver operating characteristic (ROC) curves, nomograms, and principal component analysis (PCA). Furthermore, differentially expressed genes (DEGs) were used to perform functional enrichment analyses, and to examine the behaviors of various risk groups in terms of immune-related activities and medication sensitivity. We identified 7 cuproptosis-related lncRNA signatures, including CASC19, FAM83A-AS1, AC074099.1, AC007292.2, AC026462.3, AL358944.1, and AC009019.1, as overall survival (OS) predictors. OS and progression-free survival (PFS) showed significant differences among patients in different risk groups. Independent prognostic analysis revealed that the cuproptosis-related lncRNA signatures can independently achieve patient prognosis. The risk model demonstrated strong predictive ability for patient outcomes, as evidenced by ROC curves, nomograms, and PCA. Higher tumor mutation burden (TMB) and lower tumor immune dysfunction and exclusion (TIDE) scores were observed in the high-risk group. Additionally, the low-risk group was hypersensitive to 3 anti-cancer medications, whereas the high-risk group was hypersensitive to one. A prognostic risk model with a good predictive ability based on cuproptosis-related lncRNAs was developed, providing a theoretical basis for personalized treatment and immunotherapeutic responses in pancreatic cancer.

Effect of STK3 on proliferation and apoptosis of pancreatic cancer cells via PI3K/AKT/mTOR pathway

Pancreatic cancer, as a malignant tumor with a very poor prognosis, has a high mortality. It is imperative to clarify the mechanism of pancreatic cancer development and find suitable targets for diagnosis and treatment. Serine/threonine kinase 3 (STK3) is one of the core kinases of the Hippo pathway and has the ability to inhibit tumor growth. But the biological function of STK3 in pancreatic cancer remains unknown. Here, we confirmed that STK3 has an impact on the growth, apoptosis, and metastasis of pancreatic cancer cells and investigated the related molecular mechanisms. In our research, we found that STK3 is reduced in pancreatic cancer by RT-qPCR, IHC and IF, its expression level is correlated with the clinicopathological features. CCK-8 assay, colony formation assay and flow cytometry were used to detect the effect of STK3 on the proliferation and apoptosis of pancreatic cancer cells. In addition, the Transwell assay was used to detect the ability of cell migration and invasion. The results showed that STK3 promoted apoptosis and inhibited cell migration, invasion and proliferation in pancreatic cancer. Gene set enrichment analysis (GSEA) and western blotting are used to predict and verify the pathways related to STK3. Subsequently, we found that the effect of STK3 on proliferation and apoptosis is closely related to the PI3K/AKT/mTOR pathway. Moreover, the assistance of RASSF1 plays a significant role in the regulation of PI3K/AKT/mTOR pathway by STK3. The nude mouse xenograft experiment demonstrated the tumor suppressive ability of STK3 in vivo. Collectively, this study found that STK3 regulates pancreatic cancer cell proliferation and apoptosis by suppressing the PI3K/AKT/mTOR pathway with the assistance of RASSF1.

Enhanced Glutaminolysis Drives Hypoxia-Induced Chemoresistance in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) exhibits severe hypoxia, which is associated with chemoresistance and worse patient outcome. It has been reported that hypoxia induces metabolic reprogramming in cancer cells. However, it is not well known whether metabolic reprogramming contributes to hypoxia. Here, we established that increased glutamine catabolism is a fundamental mechanism inducing hypoxia, and thus chemoresistance, in PDAC cells. An extracellular matrix component-based in vitro three-dimensional cell printing model with patient-derived PDAC cells that recapitulate the hypoxic status in PDAC tumors showed that chemoresistant PDAC cells exhibit markedly enhanced glutamine catabolism compared with chemoresponsive PDAC cells. The augmented glutamine metabolic flux increased the oxygen consumption rate via mitochondrial oxidative phosphorylation (OXPHOS), promoting hypoxia and hypoxia-induced chemoresistance. Targeting glutaminolysis relieved hypoxia and improved chemotherapy efficacy in vitro and in vivo. This work suggests that targeting the glutaminolysis-OXPHOS-hypoxia axis is a novel therapeutic target for treating patients with chemoresistant PDAC.

SIGNIFICANCE

Increased glutaminolysis induces hypoxia via oxidative phosphorylation-mediated oxygen consumption and drives chemoresistance in pancreatic cancer, revealing a potential therapeutic strategy of combining glutaminolysis inhibition and chemotherapy to overcome resistance.

Are Aspects of Integrative Concepts Helpful to Improve Pancreatic Cancer Therapy?

Numerous clinical studies have been conducted to improve the outcomes of patients suffering from pancreatic cancer. Different approaches using targeted therapeutic strategies and precision medicine methods have been investigated, and synergies and further therapeutic advances may be achieved through combinations with integrative methods. For pancreatic tumors, a particular challenge is the presence of a microenvironment and a dense stroma, which is both a physical barrier to drug penetration and a complex entity being controlled by the immune system. Therefore, the state of immunological tolerance in the tumor microenvironment must be overcome, which is a considerable challenge. Integrative approaches, such as hyperthermia, percutaneous irreversible electroporation, intra-tumoral injections, phytotherapeutics, or vitamins, in combination with standard-oncological therapies, may potentially contribute to the control of pancreatic cancer. The combined application of standard-oncological and integrative methods is currently being studied in ongoing clinical trials. An actual overview is given here.

Arsenic trioxide sensitizes pancreatic cancer cells to gemcitabine through downregulation of the TIMP1/PI3K/AKT/mTOR axis

Gemcitabine (GEM) is the first-line medication for pancreatic ductal adenocarcinoma (PDAC). However, over some treatment cycles, GEM sensitivity declines and chemotherapeutic resistance develops, resulting in tumor recurrence and metastasis. Therefore, it is critical to elucidate the mechanism of GEM chemoresistance. And a specific drug that is closely related to the mechanism is urgently required to sensitize GEM. Here, tissue inhibitor of matrix metalloproteinases 1 (TIMP1) and phosphorylated mammalian target of rapamycin (p-mTOR) were found to be substantially elevated in PDAC patients and were associated with worse overall survival. The TIMP1/PI3K/AKT/mTOR pathway was found in GEM-resistant PDAC cells and was revealed to be involved in epithelial-mesenchymal transition (EMT) and apoptosis. Furthermore, arsenic trioxide (ATO), a basic therapeutic drug for acute promyelocytic leukemia, mediated TIMP1 reduction by inducing reactive oxygen species generation and hampered the subsequent PI3K/AKT/mTOR axis. Moreover, the combination of ATO and GEM cooperatively suppressed the TIMP1/PI3K/AKT/mTOR pathway, synergistically inhibited EMT and promoted apoptosis. In vitro and in vivo, ATO combined with GEM has a collaborative anticancer effect, inhibiting cancer cell proliferation, migration, invasion, and suppressing tumor growth both in PDAC parental and GEM-resistant cells. Overall, the TIMP1/PI3K/AKT/mTOR pathway is present in PDAC and linked to GEM resistance. ATO suppresses the axis to sensitize GEM and reverse GEM resistance, suggesting a promising treatment for the disease.

Regulated cell death (RCD) in cancer: key pathways and targeted therapies

Regulated cell death (RCD), also well-known as programmed cell death (PCD), refers to the form of cell death that can be regulated by a variety of biomacromolecules, which is distinctive from accidental cell death (ACD). Accumulating evidence has revealed that RCD subroutines are the key features of tumorigenesis, which may ultimately lead to the establishment of different potential therapeutic strategies. Hitherto, targeting the subroutines of RCD with pharmacological small-molecule compounds has been emerging as a promising therapeutic avenue, which has rapidly progressed in many types of human cancers. Thus, in this review, we focus on summarizing not only the key apoptotic and autophagy-dependent cell death signaling pathways, but the crucial pathways of other RCD subroutines, including necroptosis, pyroptosis, ferroptosis, parthanatos, entosis, NETosis and lysosome-dependent cell death (LCD) in cancer. Moreover, we further discuss the current situation of several small-molecule compounds targeting the different RCD subroutines to improve cancer treatment, such as single-target, dual or multiple-target small-molecule compounds, drug combinations, and some new emerging therapeutic strategies that would together shed new light on future directions to attack cancer cell vulnerabilities with small-molecule drugs targeting RCD for therapeutic purposes.

Clinicopathological and Prognostic Value of Survivin Expression in Surgically Resected Pancreatic Ductal Adenocarcinoma

Background: Survival after surgery for pancreatic ductal adenocarcinoma (PDAC) remains poor. Thus, novel therapeutic concepts focus on the development of targeted therapies. In this context, inhibitor of apoptosis protein (IAP) survivin is regarded as a promising oncotherapeutic target. However, its expression and prognostic value in different tumour compartments of PDAC have not been studied. Methods: Immunohistochemical analysis of survivin in different PDAC tumour compartments from 236 consecutive patients was correlated with clinicopathological variables and survival. Results: In comparison to healthy pancreatic tissue high nuclear (p < 0.001) and high cytoplasmic (p < 0.01) survivin expression became evident in the tumour centre, along the invasion front and in lymph node metastases. Cytoplasmic overexpression of survivin in tumour centres was related to the presence of distant metastasis (p = 0.016) and UICC III/IV stages (p = 0.009), while high cytoplasmic expression at the invasion front grouped with venous infiltration (p = 0.022). Increased nuclear survivin along the invasion front correlated with perineural invasion (p = 0.035). High nuclear survivin in tumour centres represented an independent prognostic factor for overall survival of pancreatic tail carcinomas (HR 13.5 95%CI (1.4−129.7)) and correlated with a limited disease-free survival in PDAC (HR 1.80 95%CI (1.04−3.12)). Conclusion: Survivin is associated with advanced disease stages and poor prognosis. Therefore, survivin will help to identify patients with aggressive tumour phenotypes that could benefit from the inclusion in clinical trials incorporating survivin inhibitors in PDAC.

Ononin Shows Anticancer Activity Against Laryngeal Cancer via the Inhibition of ERK/JNK/p38 Signaling Pathway

Background

Laryngeal cancer is a type of head and neck tumor with a poor prognosis and survival rate. The new cases of laryngeal cancer increased rapidly with a higher mortality rate around the world.

Objective

The current research work was focused to unveil the in vitro antitumor effects of ononin against the laryngeal cancer Hep-2 cells.

Methodology

The cytotoxic effects of ononin against the laryngeal cancer Hep-2 cells and normal HuLa-PC laryngeal cells were studied using an 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. The intracellular Reactive Oxygen Species (ROS) generation, apoptotic cell death, Mitochondrial Membrane Potential (MMP), and cell adhesion on the 25 and 50 µM ononin-treated Hep-2 cells were detected using respective staining assays. The levels of TBARS and antioxidants were assayed using specific kits. The expressions of c-Jun N-terminal kinase 1/2 (JNK1/2), Extracellular Signal-regulated Kinase 1/2 (ERK1/2), p38, Phosphatidylinositol-3 Kinase 1/2 (PI3K1/2), and protein kinase-B (Akt) in the ononin-treated Hep-2 cells were investigated using Reverse Transcription-Polymerase Chain Reaction (RT-PCR) assay.

Results

The ononin treatment effectively inhibited the Hep-2 cell viability but did not affect the viability of HuLa-PC cells. Furthermore, the ononin treatment effectively improved the intracellular ROS accumulation, depleted the MMP, and triggered apoptosis in Hep-2 cells. The Thiobarbituric acid reactive substances (TBARS) were improved, and Glutathione (GSH) levels and Superoxide dismutase (SOD) were depleted in the ononin-administered Hep-2 cells. The ononin treatment substantially inhibited the JNK/ERK/p38 axis in the Hep-2 cells.

Conclusion

Together, the outcomes of this exploration proved that the ononin has remarkable antitumor activity against laryngeal cancer Hep-2 cells.

A nanomedicine enables synergistic chemo/photodynamic therapy for pancreatic cancer treatment

Pancreatic cancer is one of the leading causes of cancer-related deaths worldwide. Gemcitabine (Gem) has been a key chemotherapy agent for pancreatic cancer treatment by suppressing cell proliferation and inducing apoptosis. However, the overexpression of inhibitors of apoptosis (IAP) family of proteins during the carcinogenesis of pancreatic cancer can develop resistance to chemotherapy treatment and result in poor efficacy. To achieve the synergistic combinations of multiple strategies for this dismal disease, we developed a robust nanomedicine system, consisting of a photodynamic therapeutic agent (chlorine e6, Ce6) and a pro-apoptotic peptide-Gem conjugate. To have spatiotemporally controlled drug release, the pro-apoptotic peptide-Gem conjugate was designed to have a vinyldithioether linker that was sensitive to reactive oxygen species (ROS). The nanomedicine was fabricated by the direct self-assembly of the pro-apoptotic peptide-Gem conjugate with Ce6. After being delivered into tumors, the nanomedicine disassembled and rapidly released Gem, Ce6, and the pro-apoptotic peptide upon light illumination (660 nm). Both in vitro and in vivo studies in pancreatic cancer models confirmed the tumor inhibition efficacy with low systemic toxicity to animals.

Indomethacin and Diclofenac Hybrids with Oleanolic Acid Oximes Modulate Key Signaling Pathways in Pancreatic Cancer Cells

Our earlier studies showed that coupling nonsteroidal anti-inflammatory drugs (NSAIDs) with oleanolic acid derivatives increased their anti-inflammatory activity in human hepatoma cells. The aim of this study was to evaluate their effect on the signaling pathways involved in inflammation processes in human pancreatic cancer (PC) cells. Cultured PSN-1 cells were exposed for 24 h (30 µM) to OA oxime (OAO) derivatives substituted with benzyl or morpholide groups and their conjugates with indomethacin (IND) or diclofenac (DCL). The activation of NF-κB and Nrf2 was assessed by the evaluation of the translocation of their active forms into the nucleus and their binding to specific DNA sequences via the ELISA assay. The expression of NF-κB and Nrf2 target genes was evaluated by R-T PCR and Western blot analysis. The conjugation of IND or DCL with OAO derivatives increased cytotoxicity and their effect on the tested signaling pathways. The most effective compound was the DCL hybrid with OAO morpholide (4d). This compound significantly reduced the activation and expression of NF-κB and enhanced the activation and expression of Nrf2. Increased expression of Nrf2 target genes led to reduced ROS production. Moreover, MAPKs and the related pathways were also affected. Therefore, conjugate 4d deserves more comprehensive studies as a potential PC therapeutic agent.

Apoptosis as Driver of Therapy-Induced Cancer Repopulation and Acquired Cell-Resistance (CRAC): A Simple In Vitro Model of Phoenix Rising in Prostate Cancer

Apoptotic cells stimulate compensatory proliferation through the caspase-3-cPLA-2-COX-2-PGE-2-STAT3 Phoenix Rising pathway as a healing process in normal tissues. Phoenix Rising is however usurped in cancer, potentially nullifying pro-apoptotic therapies. Cytotoxic therapies also promote cancer cell plasticity through epigenetic reprogramming, leading to epithelial-to-mesenchymal-transition (EMT), chemo-resistance and tumor progression. We explored the relationship between such scenarios, setting-up an innovative, straightforward one-pot in vitro model of therapy-induced prostate cancer repopulation. Cancer (castration-resistant PC3 and androgen-sensitive LNCaP), or normal (RWPE-1) prostate cells, are treated with etoposide and left recovering for 18 days. After a robust apoptotic phase, PC3 setup a coordinate tissue-like response, repopulating and acquiring EMT and chemo-resistance; repopulation occurs via Phoenix Rising, being dependent on high PGE-2 levels achieved through caspase-3-promoted signaling; epigenetic inhibitors interrupt Phoenix Rising after PGE-2, preventing repopulation. Instead, RWPE-1 repopulate via Phoenix Rising without reprogramming, EMT or chemo-resistance, indicating that only cancer cells require reprogramming to complete Phoenix Rising. Intriguingly, LNCaP stop Phoenix-Rising after PGE-2, failing repopulating, suggesting that the propensity to engage/complete Phoenix Rising may influence the outcome of pro-apoptotic therapies. Concluding, we established a reliable system where to study prostate cancer repopulation, showing that epigenetic reprogramming assists Phoenix Rising to promote post-therapy cancer repopulation and acquired cell-resistance (CRAC).

Pharmacological Modulation of Apoptosis and Autophagy in Pancreatic Cancer Treatment

BACKGROUND

Pancreatic cancer is a fatal malignant neoplasm with infrequent signs and symptoms until a progressive stage. In 2020, GLOBOCAN reported that pancreatic cancer accounts for 4.7% of all cancer deaths. Despite the availability of standard chemotherapy regimens for treatment, the survival benefits are not guaranteed because tumor cells become chemoresistant even due to the development of chemoresistance in tumor cells even with a short treatment course, where apoptosis and autophagy play critical roles.

OBJECTIVE

This review compiled essential information on the regulatory mechanisms and roles of apoptosis and autophagy in pancreatic cancer, as well as drug-like molecules that target different pathways in pancreatic cancer eradication, with an aim to provide ideas to the scientific communities in discovering novel and specific drugs to treat pancreatic cancer, specifically PDAC.

METHOD

Electronic databases that were searched for research articles for this review were Scopus, Science Direct, PubMed, Springer Link, and Google Scholar. The published studies were identified and retrieved using selected keywords.

DISCUSSION/CONCLUSION

Many small-molecule anticancer agents have been developed to regulate autophagy and apoptosis associated with pancreatic cancer treatment, where most of them target apoptosis directly through EGFR/Ras/Raf/MAPK and PI3K/Akt/mTOR pathways. The cancer drugs that regulate autophagy in treating cancer can be categorized into three groups: i) direct autophagy inducers (e.g., rapamycin), ii) indirect autophagy inducers (e.g., resveratrol), and iii) autophagy inhibitors. Resveratrol persuades both apoptosis and autophagy with a cytoprotective effect, while autophagy inhibitors (e.g., 3-methyladenine, chloroquine) can turn off the protective autophagic effect for therapeutic benefits. Several studies showed that autophagy inhibition resulted in a synergistic effect with chemotherapy (e.g., a combination of metformin with gemcitabine/ 5FU). Such drugs possess a unique clinical value in treating pancreatic cancer as well as other autophagy-dependent carcinomas.

Class 1 Histone Deacetylases and Ataxia-Telangiectasia Mutated Kinase Control the Survival of Murine Pancreatic Cancer Cells upon dNTP Depletion

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive disease with a dismal prognosis. Here, we show how an inhibition of de novo dNTP synthesis by the ribonucleotide reductase (RNR) inhibitor hydroxyurea and an inhibition of epigenetic modifiers of the histone deacetylase (HDAC) family affect short-term cultured primary murine PDAC cells. We used clinically relevant doses of hydroxyurea and the class 1 HDAC inhibitor entinostat. We analyzed the cells by flow cytometry and immunoblot. Regarding the induction of apoptosis and DNA replication stress, hydroxyurea and the novel RNR inhibitor COH29 are superior to the topoisomerase-1 inhibitor irinotecan which is used to treat PDAC. Entinostat promotes the induction of DNA replication stress by hydroxyurea. This is associated with an increase in the PP2A subunit PR130/PPP2R3A and a reduction of the ribonucleotide reductase subunit RRM2 and the DNA repair protein RAD51. We further show that class 1 HDAC activity promotes the hydroxyurea-induced activation of the checkpoint kinase ataxia-telangiectasia mutated (ATM). Unlike in other cell systems, ATM is pro-apoptotic in hydroxyurea-treated murine PDAC cells. These data reveal novel insights into a cytotoxic, ATM-regulated, and HDAC-dependent replication stress program in PDAC cells.

Muscle-Derived Cytokines Reduce Growth, Viability and Migratory Activity of Pancreatic Cancer Cells

Simple Summary

Pancreatic cancer (PC) is a highly fatal malignancy. A major reason for the poor prognosis of patients with PC is the insensitivity to most oncological treatment approaches. It is known that regular exercise reduces the cancer risk. We have already shown that serum from advanced prostate and colon cancer patients after exercise reduces growth and viability of cancer cells. The aim of this study was to identify exercise-induced cytokines in serum from patients with advanced-stage PC that regulate cancer cell proliferation and apoptosis. Our data suggest that a mild resistance exercise training in advanced PC patients induces the release of CXCL1, IL10 and CCL4 from contracting skeletal muscle. We demonstrate that these myokines inhibit growth and migration of PC cells, and induce PC cell death. With this report we provide new knowledge on the cancer-protective function of exercise in PC. Our data strongly support sport therapies for cancer patients.

Abstract

The evidence that regular physical exercise reduces the risk of developing cancer is well described. However, the interaction between physical exercise and cancer is not fully clarified yet. Several myokines released by skeletal muscle appear to have a direct anti-tumour function. There are few data on myokine secretion after exercise in patients with advanced tumours. Pancreatic cancer (PC) is a very aggressive and usually fatal cancer. To investigate the effects of exercise in PC, the blood of advanced-stage PC patients was analysed after 12 weeks of resistance training using whole-body electromyostimulation. After the 12-week training period, the patient serum inhibited the proliferation and the motility of PC cells and enhanced PC cell apoptosis. The impact of exercise training was also investigated in an exercise-mimicking in vitro model using electric pulse stimulation of human myotubes and revealed similar anti-tumour effects on PC cells, clearly indicating direct cancer-protective properties of activated skeletal muscle. Protein and gene expression analyses in plasma from exercise-trained patients and in myotube cultures after in vitro exercise showed that interleukin 10 (IL10), C-X-C motif ligand 1 (CXCL1) and C-C motif chemokine ligand 4 (CCL4) are myokines released from activated skeletal muscle. In accordance with the effects of serum from exercise-trained patients, the supplementation with recombinant IL10, CXCL1 and CCL4 impaired growth and migration of PC cells. Treatment of PC cells with these myokines upregulated caspase 3/7 expression and the cleavage of poly(ADP-ribose) polymerase, leading to enhanced PC cell death. The identification of myokines with anti-tumour properties in advanced-stage PC patients after exercise opens a new perspective in supportive therapy with sports and exercise for cancer patients.

MicroRNA-361 suppresses the biological processes of hepatic stellate cells in HBV-relative hepatic fibrosis by NF-kappaB p65

BACKGROUND

This research study explores the effect of miR-361 on the activation of immortalized human and mice hepatic stallate cells (HSCs).

METHODS

10 liver specimens from healthy volunteers and 20 HBV-relevant HCC tissues from patients. The expressions of miR-361 in HCC patients, HBx transgenic mice, HCC cell lines expressing HBx, and human and mouse HSCs were detected. The influences of miR-361 on the biological processes of HSCs were explored. The target of miR-361 and the effects of p65 on miR-361 were also verified and analyzed.

RESULTS

Microarray analysis and quantitative real-time PCR (Q-PCR) indicated that miR-361 was decreased in HBV-relevant HCC tissues, HBx transgenic mice, HBx-transfected HepG2 cells, human and mice HSCs. Bio-informatics prediction and dual-luciferase reporter assay (DLRA) suggested that nuclear factor kappa B subunit p65 gene was a target of miR-361. Furthermore, this study showed that p65 expression was upregulated in the HBV-relevant HCC tissues, HBx transgenic mice, HBx-transfected HepG2 cells. MiR-361 upregulation also caused a reduction in p65 expression in both human and mice HSCs. In addition, p65 overexpression counteracted the effect of miR-361 in human and mice HSCs' biological processes. These findings reveal a latent mechanism underlying p65 modulation by miR-361 which is capable of initiating HSC growth and migration.

CONCLUSION

miR-361 is potentially functioning as a potent marker for HBV-relevant HCC development or liver fibrosis (LF) progression.

Fluorinated thiazolidinol drives autophagic cell death in pancreatic cancer cells via AMPK activation and perturbation of critical sentinels of oncogenic signaling

Pancreatic cancer is one of the most malignant cancers around the world. The co-occurrence of mutation in KRAS and p53 makes it highly aggressive, proliferative, metastatic, and resistant to apoptotic cell death. Therefore, there is a need to trigger an alternate mechanism of cancer cell death in apoptosis-resistant pancreatic cancer. Autophagic cell death could be an alternate viable option for treatment in such cases. Thus, the identification of small molecules as autophagy modulators with potent anticancer efficacy would be of great importance in pancreatic cancer. The present study investigates fluorinated thiazolidionol (FTZ) driven autophagy modulation, underlying mechanism, and regulation of critical sentinels of oncogenic signaling in pancreatic cancer cells. We identified that FTZ triggered autophagic cell death in pancreatic cancer cells, independent of apoptosis evidenced by an increase in cytoplasmic vacuoles formation, autophagy flux, LC3-II expression, and p62 degradation. Further, the crucial events of apoptosis i.e., Caspase-3 activation and PARP cleavage, were not observed, indicating the non-occurrence of apoptotic cell death. Moreover, FTZ was able to activate AMPK and suppress PI3k/Akt/mTOR as well as MEK/ERK, the key oncogenic signaling pathways in cancer cells. Furthermore, treatment with FTZ suppressed migration, invasion, and angiogenesis in pancreatic cancer cells. Studies in vivo revealed significant regression of tumors by FTZ in nude mice model. Overall, our study demonstrates that FTZ induces autophagic cell death in pancreatic cancer cells independent of apoptosis, which is accompanied by AMPK activation and suppression of critical sentinels of oncogenic signaling in pancreatic cancer cells.

Novel therapeutic strategies and perspectives for pancreatic cancer: Autophagy and apoptosis are key mechanisms to fight pancreatic cancer

Pancreatic cancer (PC) is the most lethal malignancy of the gastrointestinal tract. The poor prognosis of patients with PC is primarily due to lack of effective treatments against its progressive and metastatic behavior. Hence, figuring out the mechanisms underlying PC development and putting up with effective targeted therapies are of great significance to improve the prognosis of patients with PC. Apoptosis and autophagy serve to maintain tissue homoeostasis. Escaping from apoptosis or autophagy is one of the features of malignancy. PC is seriously resistant to autophagy and apoptosis, which explains its invasiveness and resistance to conventional treatment. Recently, several biological activities and pharmacological functions found in natural product extracts have been reported to inhibit PC progression. The current review focuses on understanding natural product extracts and their derivatives as one kind of novel treatments through affecting the apoptosis or autophagy in PC.

Dithiocarbazate-Copper Complexes for Bioimaging and Treatment of Pancreatic Cancer

Anticancer agents that present nonapoptotic cell death pathways are required for treating apoptosis-resistant pancreatic cancer. Here, we synthesized three fluorescent dithiocarbazate-copper complexes, {[Cu^II(L)(Cl)] 1, [Cu^II₂(L)₂(NO₃)₂] 2, and [Cu^II₂Cu^I(L)₂(Br)₃] 3}, to assess their antipancreatic cancer activities. Complexes 1-3 showed significantly greater cytotoxicity toward several pancreatic cancer cell lines with better IC₅₀ than those of the HL ligand and cisplatin. Confocal fluorescence imaging showed that complex 3 was primarily localized in the mitochondria. Primarily, compound 3 also can be applied to in vivo imaging. Further studies revealed that complex 3 kills pancreatic cancer cells by triggering multiple mechanisms, including ferroptosis. Complex 3 is the first copper complex to evoke cellular events consistent with ferroptosis in cancer cells. Finally, it significantly retarded the ASPC-1 cells' growth in a mouse xenograft model.

MicroRNA-Regulated Signaling Pathways: Potential Biomarkers for Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is the most aggressive and invasive type of pancreatic cancer (PCa) and is expected to be the second most common cause of cancer-associated deaths. The high mortality rate is due to the asymptomatic progression of the clinical features until the advanced stages of the disease and the limited effectiveness of the current therapeutics. Aberrant expression of several microRNAs (miRs/miRNAs) has been related to PDAC progression and thus they could be potential early diagnostic, prognostic, and/or therapeutic predictors for PDAC. miRs are small (18 to 24 nucleotides long) non-coding RNAs, which regulate the expression of key genes by targeting their 3′-untranslated mRNA region. Increased evidence has also suggested that the chemoresistance of PDAC cells is associated with metabolic alterations. Metabolic stress and the dysfunctionality of systems to compensate for the altered metabolic status of PDAC cells is the foundation for cellular damage. Current data have implicated multiple systems as hallmarks of PDAC development, such as glutamine redox imbalance, oxidative stress, and mitochondrial dysfunction. Hence, both the aberrant expression of miRs and dysregulation in metabolism can have unfavorable effects in several biological processes, such as apoptosis, cell proliferation, growth, survival, stress response, angiogenesis, chemoresistance, invasion, and migration. Therefore, due to these dismal statistics, it is crucial to develop beneficial therapeutic strategies based on an improved understanding of the biology of both miRs and metabolic mediators. This review focuses on miR-mediated pathways and therapeutic resistance mechanisms in PDAC and evaluates the impact of metabolic alterations in the progression of PDAC.

Mitophagy in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC), one of the most aggressive solid malignancies, is characterized by the presence of oncogenic KRAS mutations, poor response to current therapies, prone to metastasis, and a low 5-year overall survival rate. Macroautophagy (herein referred to as autophagy) is a lysosome-dependent degradation system that forms a series of dynamic membrane structures to engulf, degrade, and recycle various cargoes, such as unused proteins, damaged organelles, and invading pathogens. Autophagy is usually upregulated in established cancers, but it plays a dual role in the regulation of the initiation and progression of PDAC. As a type of selective autophagy, mitophagy is a mitochondrial quality control mechanism that uses ubiquitin-dependent (e.g., the PINK1-PRKN pathway) and -independent (e.g., BNIP3L/NIX, FUNDC1, and BNIP3) pathways to regulate mitochondrial turnover and participate in the modulation of metabolism and cell death. Genetically engineered mouse models indicate that the loss of PINK1 or PRKN promotes, whereas the depletion of BNIP3L inhibits oncogenic KRAS-driven pancreatic tumorigenesis. Mitophagy also play a dual role in the regulation of the anticancer activity of certain cytotoxic agents (e.g., rocaglamide A, dichloroacetate, fisetin, and P. suffruticosa extracts) in PDAC cells or xenograft models. In this min-review, we summarize the latest advances in understanding the complex role of mitophagy in the occurrence and treatment of PDAC.

Unraveling the Molecular Tumor-Promoting Regulation of Cofilin-1 in Pancreatic Cancer

Cofilin-1 (CFL1) overexpression in pancreatic cancer correlates with high invasiveness and shorter survival. Besides a well-documented role in actin remodeling, additional cellular functions of CFL1 remain poorly understood. Here, we unraveled molecular tumor-promoting functions of CFL1 in pancreatic cancer. For this purpose, we first show that a knockdown of CFL1 results in reduced growth and proliferation rates in vitro and in vivo, while apoptosis is not induced. By mechanistic modeling we were able to predict the underlying regulation. Model simulations indicate that an imbalance in actin remodeling induces overexpression and activation of CFL1 by acting on transcription factor 7-like 2 (TCF7L2) and aurora kinase A (AURKA). Moreover, we could predict that CFL1 impacts proliferation and apoptosis via the signal transducer and activator of transcription 3 (STAT3). These initial model-based regulations could be substantiated by studying protein levels in pancreatic cancer cell lines and human datasets. Finally, we identified the surface protein CD44 as a promising therapeutic target for pancreatic cancer patients with high CFL1 expression.

USP37 downregulation elevates the Chemical Sensitivity of Human Breast Cancer Cells to Adriamycin

Background: The evolution of adriamycin (ADR) resistance in the treatment of breast cancer often leads to a poor prognosis in patients. Ubiquitin-specific peptidase 37 (USP37) has been recently identified as a modulator in regulating the stemness of breast cancer cells, but its underlying mechanism remains unclear. In this study, we investigated whether USP37 knockdown could hamper the chemical resistance of MCF-7 and MCF-7/ADR cells to adriamycin and elucidated the potential mechanism. Methods: Immunohistochemistry, western blotting, and RT-qPCR assays were performed to detect the USP37 expression in MCF-7 and MCF-7/ADR cells. The efficiency of USP37 knockdown in breast cancer cells was confirmed by western blotting and RT-qPCR assays. We also performed CCK-8 assay, flow cytometry, western blotting, and TUNEL assays to evaluate cell viability and apoptosis in breast cancer cells. In vivo study was performed to detect the tumorigenicity of MCF-7/ADR cells transfected with shScramble or shUSP37#1 under adriamycin treatment. Results: Bioinformatic analysis indicated that USP37 overexpression was positively correlated with adriamycin resistance. The expression levels of USP37 in both MCF-7 and MCF-7/ADR cells increased significantly with the exposure to adriamycin in a dose-dependent manner. It was verified by the observation that USP37 downregulation elevated the inhibitory effects of adriamycin on breast cancer cells, suppressed cell proliferation caused by cell cycle arrest in G1/S transition, as well as induced apoptosis. Furthermore, in vivo study showed that knockdown of USP37 expression also decreased tumorigenicity of MCF-7/ADR cells in mice. TUNEL assay and observation of cell morphology magnified USP37 knockdown synergized with Adriamycin could elevate the apoptosis of MCF-7 and MCF-7/ADR cells. Western blotting assay illustrated that the combination of USP37 knockdown with adriamycin treatment significantly upregulated the expression levels of cleaved caspase 3 and Bax, whereas the expression level of Bcl-2 was inhibited. Conclusion: Knockdown of USP37 gene expression can reverse the resistance of breast cancer cells to adriamycin, and down-regulating USP37 might be a valuable strategy against ADR resistance in breast cancer therapy.

Synthetic Conjugates of Ursodeoxycholic Acid Inhibit Cystogenesis in Experimental Models of Polycystic Liver Disease

BACKGROUND AND AIMS

Polycystic liver diseases (PLDs) are genetic disorders characterized by progressive development of symptomatic biliary cysts. Current surgical and pharmacological approaches are ineffective, and liver transplantation represents the only curative option. Ursodeoxycholic acid (UDCA) and histone deacetylase 6 inhibitors (HDAC6is) have arisen as promising therapeutic strategies, but with partial benefits.

APPROACH AND RESULTS

Here, we tested an approach based on the design, synthesis, and validation of a family of UDCA synthetic conjugates with selective HDAC6i capacity (UDCA-HDAC6i). Four UDCA-HDAC6i conjugates presented selective HDAC6i activity, UDCA-HDAC6i #1 being the most promising candidate. UDCA orientation within the UDCA-HDAC6i structure was determinant for HDAC6i activity and selectivity. Treatment of polycystic rats with UDCA-HDAC6i #1 reduced their hepatomegaly and cystogenesis, increased UDCA concentration, and inhibited HDAC6 activity in liver. In cystic cholangiocytes UDCA-HDAC6i #1 restored primary cilium length and exhibited potent antiproliferative activity. UDCA-HDAC6i #1 was actively transported into cells through BA and organic cation transporters.

CONCLUSIONS

These UDCA-HDAC6i conjugates open a therapeutic avenue for PLDs.

Extracellular Matrix Composition Modulates the Responsiveness of Differentiated and Stem Pancreatic Cancer Cells to Lipophilic Derivate of Gemcitabine

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal disease. Gemcitabine (GEM) is used as the gold standard drug in PDAC treatment. However, due to its poor efficacy, it remains urgent to identify novel strategies to overcome resistance issues. In this context, an intense stroma reaction and the presence of cancer stem cells (CSCs) have been shown to influence PDAC aggressiveness, metastatic potential, and chemoresistance.

METHODS

We used three-dimensional (3D) organotypic cultures grown on an extracellular matrix composed of Matrigel or collagen I to test the effect of the new potential therapeutic prodrug 4-(N)-stearoyl-GEM, called C18GEM. We analyzed C18GEM cytotoxic activity, intracellular uptake, apoptosis, necrosis, and autophagy induction in both Panc1 cell line (P) and their derived CSCs.

RESULTS

PDAC CSCs show higher sensitivity to C18GEM treatment when cultured in both two-dimensional (2D) and 3D conditions, especially on collagen I, in comparison to GEM. The intracellular uptake mechanisms of C18GEM are mainly due to membrane nucleoside transporters' expression and fatty acid translocase CD36 in Panc1 P cells and to clathrin-mediated endocytosis and CD36 in Panc1 CSCs. Furthermore, C18GEM induces an increase in cell death compared to GEM in both cell lines grown on 2D and 3D cultures. Finally, C18GEM stimulated protective autophagy in Panc1 P and CSCs cultured on 3D conditions.

CONCLUSION

We propose C18GEM together with autophagy inhibitors as a valid alternative therapeutic approach in PDAC treatment.

Get rid of pancreatic cancer by inhibiting garbage disposal?: Comment on "UAE1 Inhibition mediates the unfolded protein response, DNA damage and caspase-dependent cell death in pancreatic cancer" by Rehemtulla et al

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stress pathways including the ER stress, the proteasome and the unfolded protein response (UPR) are increasingly reported to be suitable targets in PDAC

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UAE1 is the most abundant of two ubiquitin activating enzymes (UAE) regulating the initial step of the ER stress associated protein degradation (ERAD) pathway

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The group of Rehemtulla elegantly showed that TAK-243, a small molecule inhibitor of Ubiquitin activating enzyme 1 (UAE1) nduced apoptosis in PDAC cells and a subcutaneous mouse model of the disease

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In other preclinical models of cancer, especially in lymphatic malignancies, this compound showed promising results in directly inducing apoptosis but also in increasing the response to other conventional cytotoxic therapeutic approaches

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Strikingly, these effects were also reported in cells resistant to drugs that target other protein degradation pathways, like proteasome inhibitors, indicating divergent molecular mechanisms.

Modulation of Apoptosis by Plant Polysaccharides for Exerting Anti-Cancer Effects: A Review

Cancer has become a significant public health problem with high disease burden and mortality. At present, radiotherapy and chemotherapy are the main means of treating cancer, but they have shown serious safety problems. The severity of this problem has caused further attention and research on effective and safe cancer treatment methods. Polysaccharides are natural products with anti-cancer activity that are widely present in a lot of plants, and many studies have found that inducing apoptosis of cancer cells is one of their important mechanisms. Therefore, this article reviews the various ways in which plant polysaccharides promote apoptosis of cancer cells. The major apoptotic pathways involved include the mitochondrial pathway, the death receptor pathway, and their upstream signal transduction such as MAPK pathway, PI3K/AKT pathway, and NF-κB pathway. Moreover, the paper has also been focused on the absorption and toxicity of plant polysaccharides with reference to extant literature, making the research more scientific and comprehensive. It is hoped that this review could provide some directions for the future development of plant polysaccharides as anticancer drugs in pharmacological experiments and clinical researches.

Akt inhibitor MK-2206 reduces pancreatic cancer cell viability and increases the efficacy of gemcitabine

The PI3K/Akt pathway is an attractive therapeutic target in the treatment of pancreatic cancer, as it was demonstrated to be aberrantly regulated in pancreatic cancer cells. The present study aimed to investigate the therapeutic potential of the novel Akt inhibitor MK-2206 in human pancreatic cancer cell lines. Pancreatic cancer cell survival following MK-2206 treatment was assessed using the Cell Counting Kit-8 (CCK-8) assay, colony formation and determination of the apoptotic rate by flow cytometry following annexin-V-fluorescein isothiocyanate/propidium iodide staining. The effects of MK-2206 alone or in combination with gemcitabine on pancreatic cell proliferation were assessed using the CCK-8 assay. Western blotting was used to examine the effects of the two drugs on Akt protein expression. The results demonstrated that MK-2206 inhibited the proliferation and induced apoptosis of the Mia PaCa-2 and Panc-1 pancreatic cancer cell lines. In addition, CCK-8 cytotoxicity test showed that combined administration of MK-2206 with gemcitabine enhanced the cytotoxic efficacy of gemcitabine. Furthermore, a low dose of MK-2206 (1 µM) combined with gemcitabine was enough to inhibit Akt phosphorylation. Taken together, these results provided some insight into the underlying mechanism of the anticancer effects of MK-2206 on pancreatic cancer cells.

MicroRNA-9119 regulates cell viability of granulosa cells in polycystic ovarian syndrome via mediating Dicer expression

Polycystic ovary syndrome (PCOS) is a hormonal disorder common among women of reproductive age. Although much is understood concerning the pathology of PCOS, further investigation into the influence of microribonucleic acids (miRNAs) on the proliferation of ovarian granulosa cells (GCs) is needed. This study investigated the role of specific miRNAs in ovarian dysfunction of PCOS and its effect on the proliferation of GCs. Initially, miRNA profiling was performed on the ovarian cortexes of 15 rats in which PCOS had been induced and 15 rats without PCOS (non-PCOS). This mechanical study was performed on ovarian GCs extracted from human chorionic gonadotrophin (hCG)-induced rats. Insulin was used to treat GCs to establish the PCOS cell model. Increased Equus caballus mir-9119 expression was observed and confirmed in the insulin-induced model of PCOS in GCs (GC-PCOS) as well as in the hCG-induced rats when compared to non-PCOS rats and cells. Observation and confirmation were carried out through both miRNA array and quantitative PCR. In contrast, downregulation of the nuclear factor kappa B (NFκB) p65 was observed in the PCOS cell model. Additionally, annexin V, FITC, and propidium iodide flow cytometry showed overexpression of miR-9119-induced apoptosis. In this study, we revealed that miR-9119 inhibition regulates p65 expression levels in insulin-treated GCs by binding to the 3'-untranslated of p65. Additionally, regulation of p65 expression was positively correlated with the expression of the double-stranded RNA endoribonuclease DICER. Moreover, RNA silencing/overexpression of p65 affected the functional role of miR-9119. In conclusion, GCs of PCOS, the expression of miR-9119, and targeted NFκB/p65-DICER axis are upregulated in order to maintain cell viability and prevent apoptosis, thereby promoting Anti-Müllerian hormone production in GCs. This study may provide a new understanding of the mechanism of GC dysfunction.

Activation of PERK Contributes to Apoptosis and G2/M Arrest by Microtubule Disruptors in Human Colorectal Carcinoma Cells ‡

Microtubule-targeting agents (MTAs) are widely used in cancer chemotherapy, but the therapeutic responses significantly vary among different tumor types. Protein kinase RNA-like endoplasmic reticular (ER) kinase (PERK) is an ER stress kinase, and the role of PERK in the anticancer effects of MTAs is still undefined. In the present study, taxol (TAX) and nocodazole (NOC) significantly induced apoptosis with increased expression of phosphorylated PERK (pPERK; Tyr980) in four human colon cancer cell lines, including HCT-15, COLO205, HT-20, and LOVO cells. Induction of G₂/M arrest by TAX and NOC with increases in phosphorylated Cdc25C and cyclin B1 protein were observed in human colon cancer cells. Application of the c-Jun N-terminal kinase (JNK) inhibitors SP600125 (SP) and JNK inhibitor V (JNKI) significantly reduced TAX- and NOC-induced apoptosis and G₂/M arrest of human colon cancer cells. Interestingly, TAX- and NOC-induced pPERK (Tyr980) protein expression was inhibited by adding the JNK inhibitors, SP and JNKI, and application of the PERK inhibitor GSK2606414 (GSK) significantly reduced apoptosis and G₂/M arrest by TAX and NOC, with decreased pPERK (Tyr980) and pJNK, phosphorylated Cdc25C, and Cyc B1 protein expressions in human colon cancer cells. Decreased viability by TAX and NOC was inhibited by knockdown of PERK using PERK siRNA in COLO205 and HCT-15 cells. Disruption of the mitochondrial membrane potential and an increase in B-cell lymphoma-2 (Bcl-2) protein phosphorylation (pBcl-2; Ser70) by TAX and NOC were prevented by adding the PERK inhibitor GSK and JNK inhibitor SP and JNKI. A cross-activation of JNK and PERK by TAX and NOC leading to anti-CRC actions including apoptosis and G₂/M arrest was first demonstrated herein.

NF-κB Dependent Chemokine Signaling in Pancreatic Cancer

Pancreatic cancer is one of the carcinomas with the worst prognoses, as shown by its five-year survival rate of 9%. Although there have been new therapeutic innovations, the effectiveness of these therapies is still limited, resulting in pancreatic ductal adenocarcinoma (PDAC) becoming the second leading cause of cancer-related death in 2020 in the US. In addition to tumor cell intrinsic resistance mechanisms, this disease exhibits a complex stroma consisting of fibroblasts, immune cells, neuronal and vascular cells, along with extracellular matrix, all conferring therapeutic resistance by several mechanisms. The NF-κB pathway is involved in both the tumor cell-intrinsic and microenvironment-mediated therapeutic resistance by regulating the transcription of a plethora of target genes. These genes are involved in nearly all scenarios described as the hallmarks of cancer. In addition to classical regulators of apoptosis, NF-κB regulates the expression of chemokines and their receptors, both in the tumor cells and in cells of the microenvironment. These chemokines mediate autocrine and paracrine loops among tumor cells but also cross-signaling between tumor cells and the stroma. In this review, we will focus on NF-κB-mediated chemokine signaling, with an emphasis on therapy resistance in pancreatic cancer.

Colorectal cancer cell-derived CCL20 recruits regulatory T cells to promote chemoresistance via FOXO1/CEBPB/NF-κB signaling

Background

Colorectal cancer (CRC) is one of the most common forms of cancer worldwide. The tumor microenvironment plays a key role in promoting the occurrence of chemoresistance in solid cancers. Effective targets to overcome resistance are necessary to improve the survival and prognosis of CRC patients. This study aimed to evaluate the molecular mechanisms of the tumor microenvironment that might be involved in chemoresistance in patients with CRC.

Methods

We evaluated the effects of CCL20 on chemoresistance of CRC by recruitment of regulatory T cells (Tregs) in vitro and in vivo.

Results

We found that the level of CCL20 derived from tumor cells was significantly higher in Folfox-resistant patients than in Folfox-sensitive patients. The high level of CCL20 was closely associated with chemoresistance and poor survival in CRC patients. Among the drugs in Folfox chemotherapy, we confirmed that 5-FU increased the expression of CCL20 in CRC. Moreover, CCL20 derived from 5-FU-resistant CRC cells promoted recruitment of Tregs. Tregs further enhanced the chemoresistance of CRC cells to 5-FU. FOXO1/CEBPB/NF-κB signaling was activated in CRC cells after 5-FU treatment and was required for CCL20 upregulation mediated by 5-FU. Furthermore, CCL20 blockade suppressed tumor progression and restored 5-FU sensitivity in CRC. Lastly, the expression of these signaling molecules mediating chemoresistance was closely correlated with poor survival of CRC patients.

Conclusions

CRC cell-secreted CCL20 can recruit Tregs to promote chemoresistance via FOXO1/CEBPB/NF-κB signaling, indicating that the FOXO1/CEBPB/NF-κB/CCL20 axis might provide a promising target for CRC treatment.

Electronic supplementary material

The online version of this article (10.1186/s40425-019-0701-2) contains supplementary material, which is available to authorized users.

The ERBB receptor inhibitor dacomitinib suppresses proliferation and invasion of pancreatic ductal adenocarcinoma cells

PURPOSE

Pancreatic ductal adenocarcinoma (PDAC), the most common malignancy of the pancreas, is the fourth most common cause of cancer-related death in the USA. Local progression, early tumor dissemination and low efficacy of current treatments are the major reasons for its high mortality rate. The ERBB family is over-expressed in PDAC and plays essential roles in its tumorigenesis; however, single-targeted ERBB inhibitors have shown limited activity in this disease. Here, we examined the anti-tumor activity of dacomitinib, a pan-ERBB receptor inhibitor, on PDAC cells.

METHODS

Anti-proliferative effects of dacomitinib were determined using a cell proliferation assay and crystal violet staining. Annexin V/PI staining, radiation therapy and cell migration and invasion assays were carried out to examine the effects of dacomitinib on apoptosis, radio-sensitivity and cell motility, respectively. Quantitative reverse transcription-PCR (qRT-PCR) and Western blot analyses were applied to elucidate the molecular mechanisms underlying the anti-tumor activity of dacomitinib.

RESULTS

We found that dacomitinib diminished PDAC cell proliferation via inhibition of FOXM1 and its targets Aurora kinase B and cyclin B1. Moreover, we found that dacomitinib induced apoptosis and potentiated radio-sensitivity via inhibition of the anti-apoptotic proteins survivin and MCL1. Treatment with dacomitinib attenuated cell migration and invasion through inhibition of the epithelial-to-mesenchymal transition (EMT) markers ZEB1, Snail and N-cadherin. In contrast, we found that the anti-tumor activity of single-targeted ERBB agents including cetuximab (anti-EGFR mAb), trastuzumab (anti-HER2 mAb), H3.105.5 (anti-HER3 mAb) and erlotinib (EGFR small molecule inhibitor) were marginal.

CONCLUSIONS

Our findings indicate that dacomitinib-mediated blockade of the ERBB receptors yields advantages over single-targeted ERBB inhibition and provide a rationale for further investigation of the therapeutic potential of dacomitinib in the treatment of ERBB-driven PDAC.

Neutrophil-mimicking therapeutic nanoparticles for targeted chemotherapy of pancreatic carcinoma

Due to the critical correlation between inflammation and carcinogenesis, a therapeutic candidate with anti-inflammatory activity may find application in cancer therapy. Here, we report the therapeutic efficacy of celastrol as a promising candidate compound for treatment of pancreatic carcinoma via naïve neutrophil membrane-coated poly(ethylene glycol) methyl ether-block-poly(lactic-co-glycolic acid) (PEG-PLGA) nanoparticles. Neutrophil membrane-coated nanoparticles (NNPs) are well demonstrated to overcome the blood pancreas barrier to achieve pancreas-specific drug delivery in vivo. Using tumor-bearing mice xenograft model, NNPs showed selective accumulations at the tumor site following systemic administration as compared to nanoparticles without neutrophil membrane coating. In both orthotopic and ectopic tumor models, celastrol-loaded NNPs demonstrated greatly enhanced tumor inhibition which significantly prolonged the survival of tumor bearing mice and minimizing liver metastases. Overall, these results suggest that celastrol-loaded NNPs represent a viable and effective treatment option for pancreatic carcinoma.

GATA1 Promotes Gemcitabine Resistance in Pancreatic Cancer through Antiapoptotic Pathway

Gemcitabine-based chemotherapy is the first-line treatment for pancreatic cancer. However, chemoresistance is a major obstacle to drug efficacy, leading to poor prognosis. Little progress has been achieved although multiple mechanisms are investigated. Therefore, effective strategies are urgently needed to overcome drug resistance. Here, we demonstrate that the transcription factor GATA binding protein 1 (GATA1) promotes gemcitabine resistance in pancreatic cancer through antiapoptotic pathway. GATA1 is highly expressed in pancreatic ductal adenocarcinoma (PDAC) tissues, and GATA1 status is an independent predictor of prognosis and response to gemcitabine therapy. Further investigation demonstrates GATA1 is involved in both intrinsic and acquired gemcitabine resistance in PDAC cells. Mechanistically, we find that GATA1 upregulates Bcl-XL expression by binding to its promoter and thus induces gemcitabine resistance through enhancing Bcl-XL mediated antiapoptosis in vitro and in vivo. Moreover, in PDAC patients, Bcl-XL expression is positively correlated with GATA1 level and predicts clinical outcomes and gemcitabine response. Taken together, our results indicate that GATA1 is a novel marker and potential target for pancreatic cancer. Targeting GATA1 combined with Bcl-XL may be a promising strategy to enhance gemcitabine response.

Norleual, a hepatocyte growth factor and macrophage stimulating protein dual antagonist, increases pancreatic cancer sensitivity to gemcitabine

Pancreatic cancer is a leading cause of cancer deaths in the USA and is characterized by an exceptionally poor long-term survival rate compared with other major cancers. The hepatocyte growth factor (HGF) and macrophage stimulating protein (MSP) growth factor systems are frequently over-activated in pancreatic cancer and significantly contribute to cancer progression, metastasis, and chemotherapeutic resistance. Small molecules homologous to the 'hinge' region of HGF, which participates in its dimerization and activation, had been developed and shown to bind HGF with high affinity, antagonize HGF's actions, and possess anticancer activity. Encouraged by sequence homology between HGF's hinge region and a similar sequence in MSP, our laboratory previously investigated and determined that these same antagonists could also block MSP-dependent cellular responses. Thus, the purpose of this study was to establish that the dual HGF/MSP antagonist Norleual could inhibit the prosurvival activity imparted by both HGF and MSP to pancreatic cancer cells in vitro, and to determine whether this effect translated into an improved chemotherapeutic impact for gemcitabine when delivered in combination in a human pancreatic cancer xenograft model. Our results demonstrate that Norleual does indeed suppress HGF's and MSP's prosurvival effects as well as sensitizing pancreatic cancer cells to gemcitabine in vitro. Most importantly, treatment with Norleual in combination with gemcitabine markedly inhibited in-vivo tumor growth beyond the suppression observed with gemcitabine alone. These results suggest that dual functional HGF/MSP antagonists like Norleual warrant further development and may offer an improved therapeutic outcome for pancreatic cancer patients.

Lycopene Inhibits Reactive Oxygen Species-Mediated NF-κB Signaling and Induces Apoptosis in Pancreatic Cancer Cells

Generation of excess quantities of reactive oxygen species (ROS) caused by mitochondrial dysfunction facilitates rapid growth of pancreatic cancer cells. Elevated ROS levels in cancer cells cause an anti-apoptotic effect by activating survival signaling pathways, such as NF-κB and its target gene expression. Lycopene, a carotenoid found in tomatoes and a potent antioxidant, displays a protective effect against pancreatic cancer. The present study was designed to determine if lycopene induces apoptosis of pancreatic cancer PANC-1 cells by decreasing intracellular and mitochondrial ROS levels, and consequently suppressing NF-κB activation and expression of NF-κB target genes including cIAP1, cIAP2, and survivin. The results show that the lycopene decreased intracellular and mitochondrial ROS levels, mitochondrial function (determined by the mitochondrial membrane potential and oxygen consumption rate), NF-κB activity, and expression of NF-κB-dependent survival genes in PANC-1 cells. Lycopene reduced cell viability with increases in active caspase-3 and the Bax to Bcl-2 ratio in PANC-1 cells. These findings suggest that supplementation of lycopene could potentially reduce the incidence of pancreatic cancer.

miR-506 contributes to malignancy of cutaneous squamous cell carcinoma via targeting of P65 and LAMC1

Previous research has shown that microRNA 506 (miR-506) functions as an essential modulator in the development of many biological reactions, including multiple cancers. However, its involvement in cutaneous squamous cell carcinoma (CSCC) has been rarely reported. In the present work, we investigated the molecular mechanism and function of miR-506 in the regulation of CSCC cell viability and metastasis (migration and invasion). We observed that miR-506 expression was upregulated in both CSCC tissues and cell lines, and that decreased miR-506 expression led to repressed tumorigenesis in CSCC cells. Furthermore, flow cytometry revealed that the depletion of miR-506 resulted in decreased proliferation and increased apoptotic levels in CSCC cells. Meanwhile, it was found that miR-506 decreased CSCC cell migration and invasion in vitro. The dual-luciferase reporter assay also revealed that miR-506 targets the 3'-UTRs of p65 and Laminin C1 (LAMC1) for silencing. Silencing of p65 expression counteracted the pro-apoptotic influence of miR-506 depletion in CSCC cells, while inhibition of LAMC1 expression restored the migration and invasion properties of the CSCC cells. Therefore, the results provide evidence for the need to probe the biological and molecular mechanisms behind the development and progression of CSCC and may lead to novel treatment CSCC strategies.

SIRT6 overexpression induces apoptosis of nasopharyngeal carcinoma by inhibiting NF-κB signaling

BACKGROUND

Previous reports show that SIRT6 serves as a critical modulator of the development of multiple malignancies as well as other disorders. However, its role in nasopharyngeal carcinoma (NPC) is unknown. Thus, we elucidated the effects of SIRT6 on the survival of NPC cells, and modulation of cell death.

METHODS

We found that expression of SIRT6 is downregulated in ten human NPC specimens as well as in the human NPC cell lines, 5-8 F and CNE1, as compared with that in healthy tissues and normal nasopharyngeal NP69 cells. The MTT assay and colony formation assay revealed that upregulation of SIRT6 impaired the proliferation, as well as the survival of 5-8 F and CNE1 cells. The TUNEL assay, annexin V-FITC/propidium iodide, and flow cytometry were performed to detect apoptosis. The results revealed that the expression of SIRT6 resulted in increased apoptosis.

RESULTS

Western blotting results showed that SIRT6 overexpression decreased anti-apoptotic Bcl-2 levels, whereas it promoted an increase in pro-apoptotic Bax and cleaved caspase-3 levels. Moreover, NF-κB levels were markedly reduced in cells expressing SIRT6, whereas they were increased in cells transfected with shRNA-SIRT6. Recovery of NF-κB expression was found to counter the suppressive influence of SIRT6 on NPC cell survival, whereas, NF-κB knockdown increased apoptosis of NPC cells.

CONCLUSION

Thus, the findings of our study offer insight into the biological and molecular mechanisms underlying the development of NPC and may lead to the development of new and innovative strategies for the treatment of NPC.

TRAIL/NF-κB/CX3CL1 Mediated Onco-Immuno Crosstalk Leading to TRAIL Resistance of Pancreatic Cancer Cell Lines

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignant neoplasms and registers rising death rates in western countries. Due to its late detection in advanced stages, its extremely aggressive nature and the minimal effectiveness of currently available therapies, PDAC is a challenging problem in the clinical field. One characteristic of PDAC is a distinct desmoplasia consisting of fibroblasts, endothelial and immune cells as well as non-cellular components, contributing to therapy resistance. It is well established that the NF-κB signaling pathway controls inflammation, cancer progression and apoptosis resistance in PDAC. This study attempts to identify NF-κB target genes mediating therapy resistance of humane PDAC cell lines towards death ligand induced apoptosis. By using a genome wide unbiased approach the chemokine CX3CL1 was established as a central NF-κB target gene mediating therapy resistance. While no direct impact of CX3CL1 expression on cancer cell apoptosis was identified in co-culture assays it became apparent that CX3CL1 is acting in a paracrine fashion, leading to an increased recruitment of inflammatory cells. These inflammatory cells in turn mediate apoptosis resistance of PDAC cells. Therefore, our data dissect a bifunctional cross-signaling pathway in PDAC between tumor and immune cells giving rise to therapy resistance.

Girdin regulates the proliferation and apoptosis of pancreatic cancer cells via the PI3K/Akt signalling pathway

Girdin functions as an Akt phosphorylation enhancer (APE), which expedites the proliferation and survival of many types of tumours. However, the influence of Girdin on pancreatic cancer and the underlying molecular mechanisms have yet to be uncovered. Hence, in the present study, we sought to elucidate the function of Girdin in pancreatic cancer malignancy, particularly its role in pancreatic cancer cell proliferation, migration and apoptosis. Immunohistochemistry (IHC) was used to evaluate Girdin expression in pancreatic cancer tissues and to analyse its correlation with pathological grade. Girdin expression was further validated in pancreatic cancer cell lines (AsPC-1, BxPC-3 and PANC-1), and human pancreatic ductal epithelial (HPNE) cells were used as a control. Recombinant adenovirus vectors containing Girdin-siRNA were constructed to inhibit Girdin expression and were used in subsequent experiments to determine the effects of Girdin silencing on pancreatic cancer cells. Girdin silencing suppressed pancreatic cancer cell proliferation and induced pancreatic cancer cell apoptosis in vitro and in vivo. According to the results of further mechanistic investigations, Girdin may regulate cell processes through the phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt) signalling pathway to exert additive effects on pancreatic cancer.

OSU-A9 inhibits pancreatic cancer cell lines by modulating p38-JAK-STAT3 signaling

Pancreatic cancer is an aggressive malignancy that is the fourth leading cause of death worldwide. Since there is a dire need for novel and effective therapies to improve the poor survival rates of advanced pancreatic cancer patients, we analyzed the antitumor effects of OSU-A9, an indole-3-carbinol derivative, on pancreatic cancer cell lines in vitro and in vivo. OSU-A9 exhibited a stronger antitumor effect than gemcitabine on two pancreatic cancer cell lines, including gemcitabine-resistant PANC-1 cells. OSU-A9 treatment induced apoptosis, the down-regulation of Akt phosphorylation, up-regulation of p38 phosphorylation and decreased phosphorylation of JAK and STAT3. Cell migration and invasiveness assays showed that OSU-A9 reduced cancer cell aggressiveness and inhibited BxPC-3 xenograft growth in nude mice. These results suggest that OSU-A9 modulates the p38-JAK-STAT3 signaling module, thereby inducing cytotoxicity in pancreatic cancer cells. Continued evaluation of OSU-A9 as a potential therapeutic agent for pancreatic cancer thus appears warrented.

Identification of novel therapeutic target genes and pathway in pancreatic cancer by integrative analysis

BACKGROUND

Gene alterations are crucial to the molecular pathogenesis of pancreatic cancer. The present study was designed to identify the potential candidate genes in the pancreatic carcinogenesis.

METHODS

Gene Expression Omnibus database (GEO) datasets of pancreatic cancer tissue were retrieval and the differentially expressed genes (DEGs) from individual microarray data were merged. Gene Ontology (GO) enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, protein-protein interaction (PPI) networks, and gene coexpression analysis were performed.

RESULTS

Three GEO datasets, including 74 pancreatic cancer samples and 55 controls samples were selected. A total of 2325 DEGs were identified, including 1383 upregulated and 942 downregulated genes. The GO terms for molecular functions, biological processes, and cellular component were protein binding, small molecule metabolic process, and integral to membrane, respectively. The most significant pathway in KEGG analysis was metabolic pathways. PPI network analysis indicated that the significant hub genes including cytochrome P450, family 2, subfamily E, polypeptide 1 (CYP2E1), mitogen-activated protein kinase 3 (MAPK3), and phospholipase C, gamma 1 (PLCG1). Gene coexpression network analysis identified 4 major modules, and the potassium channel tetramerization domain containing 10 (KCTD10), kin of IRRE like (KIRREL), dipeptidyl-peptidase 10 (DPP10), and unc-80 homolog (UNC80) were the hub gene of each modules, respectively.

CONCLUSION

Our integrative analysis provides a comprehensive view of gene expression patterns associated with the pancreatic carcinogenesis.

Sporamin induces apoptosis and inhibits NF-κB activation in human pancreatic cancer cells

Sporamin, a Kunitz-type trypsin inhibitor (TI) from sweet potato tuberous roots, has demonstrated anti-tumor activity through poorly defined mechanisms. Furthermore, the effects of sporamin on pancreatic cancer have not been explored. Herein, we studied the effects of sporamin on two human pancreatic cancer cell lines, PANC-1 and BxPC-3. Sporamin significantly inhibited the cell viability and proliferation activity and induced apoptosis in PANC-1 and BxPC-3 cells. Consistently, in sporamin-treated PANC-1 and BxPC-3 cells, the anti-apoptotic proteins Bcl-2 and Bcl-XL were downregulated and the pro-apoptotic protein Bax was upregulated. Moreover, nuclear factor kappa B activation and IκBα phosphorylation were inhibited, and total IκBα expression was increased in sporamin-treated PANC-1 and BxPC-3 cells. Thus, our results suggest that the anti-tumor effects of sporamin in pancreatic cancer cells might result partly from induction of apoptosis by downregulating nuclear factor kappa B pathway.