Therapeutic targeting of pancreatic cancer stem cells by dexamethasone modulation of the MKP-1-JNK axis

Domatinostat Targets the FOXM1-Survivin Axis to Reduce the Viability of Ovarian Cancer Cells Alone and in Combination with Chemotherapeutic Agents

The deregulation of the FOXM1 transcription factor is a key molecular alteration in ovarian cancer, contributing to the development and progression of ovarian cancer via activation of the target genes. As such, FOXM1 is a highly attractive therapeutic target in the treatment of ovarian cancer, but there has been no clinically tested FOXM1 inhibitor to date. We investigated in this study the effects of domatinostat, a class I-selective HDAC inhibitor currently in the clinical stage of development as a cancer therapeutic, on the expression of FOXM1 and viability of ovarian cancer cells. Cell viability, as well as protein and mRNA expression of FOXM1 and its transcriptional target survivin, was examined after domatinostat treatment of TOV21G and SKOV3 ovarian cancer cell lines in the absence or presence of cisplatin and paclitaxel. The effect of FOXM1 knockdown on survivin expression and those of genetic and pharmacological inhibition of survivin alone or in combination with the chemotherapeutic agents on cell viability were also examined. Domatinostat reduced the protein and mRNA expression of FOXM1 and survivin and also the viability of ovarian cancer cells alone and in combination with cisplatin or paclitaxel at clinically relevant concentrations. Knockdown experiments showed survivin expression was dependent on FOXM1 in ovarian cancer cells. Survivin inhibition was sufficient to reduce the viability of ovarian cancer cells alone and in combination with the chemotherapeutic agents. Our findings suggest that domatinostat, which effectively targets the FOXM1-survivin axis required for the viability of ovarian cancer cells, is a promising option for the treatment of ovarian cancer.

Roles of cancer stem cells in gastrointestinal cancers

Cancer stem cells (CSCs) are the main cause of tumor growth, invasion, metastasis and recurrence. Recently, CSCs have been extensively studied to identify CSC-specific surface markers as well as signaling pathways that play key roles in CSCs self-renewal. The involvement of CSCs in the pathogenesis of gastrointestinal (GI) cancers also highlights these cells as a priority target for therapy. The diagnosis, prognosis and treatment of GI cancer have always been a focus of attention. Therefore, the potential application of CSCs in GI cancers is receiving increasing attention. This review summarizes the role of CSCs in GI cancers, focusing on esophageal cancer, gastric cancer, liver cancer, colorectal cancer, and pancreatic cancer. In addition, we propose CSCs as potential targets and therapeutic strategies for the effective treatment of GI cancers, which may provide better guidance for clinical treatment of GI cancers.

Cancer Stem Cells and Their Therapeutic Usage

Cancer stem cells (CSC) have unique characteristics which include self-renewal, multi-directional differentiation capacity, quiescence/dormancy, and tumor-forming capability. These characteristics are referred to as the "stemness" properties. Tumor microenvironment contributes to CSC survival, function, and remaining them in an undifferentiated state. CSCs can form malignant tumors with heterogeneous phenotypes mediated by the tumor microenvironment. Therefore, the crosstalk between CSCs and tumor microenvironment can modulate tumor heterogeneity. CSCs play a crucial role in several biological processes, epithelial-mesenchymal transition (EMT), autophagy, and cellular stress response. In this chapter, we focused characteristics of cancer stem cells, reprogramming strategies cells into CSCs, and then we highlighted the contribution of CSCs to therapy resistance and cancer relapse and their potential of therapeutic targeting of CSCs.

The inhibitory effect and mechanism of Yi-qi-hua-yu-jie-du decoction on the drug resistance of gastric cancer stem cells based on ABC transporters

Background

The drug resistance of tumor stem cells is an obstacle in gastric cancer (GC) treatment and the high expression of ABC transporters is a classic reason for drug resistance. This study aimed to construct a reliable GC drug-resistant stem cell model and explore the inhibitory effect and mechanism of Yi-qi-hua-yu-jie-du medicated serum (YQHY) on the drug resistance of GC stem cells based on ABC transporters.

Methods

The tumor stemness biomarker CD44 was primary identification from WGCNA. The magnetic-activated cell sorting (MACS) method was used to separate CD44( +)BGC823/5-Fu (BGC823/5–Fu-CSCs) cells and the stemness characteristics were verified from multiple dimensions. Then, the drug resistance index and expression of ABC transporter genes MDR1 and MRP1 were detected in CD44(−)/CD44(+) cells. The inhibition and apoptosis rates of the cells administrated with YQHY or/and 5-Fu were calculated to confirm that YQHY can suppress the drug resistance of BGC823/5-Fu-CSCs. Afterwards, the effects of YQHY on the expression of MDR1 and MRP1 and the activation of the PI3K/Akt/Nrf2 pathway were observed. Finally, under the administration of IGF-1 (the activator of PI3K/Akt pathway) and Nrf2 siRNA, the mechanism of YQHY on reversing the drug resistance of BGC823/5–Fu-CSCs through inhibiting the expression of MDR1 and MRP1 via PI3K/Akt/Nrf2 was verified.

Results

CD44 was a reliable GC stemness biomarker and can be applied to construct the drug-resistant GC stem cell model CD44(+)BGC823/5-Fu. The growth rate, cell proliferation index, soft agar colony formation, expression of stemness specific genes and tumorigenesis ability of CD44(+)BGC823/5-Fu cells were significantly higher than those of CD44(−)BGC823/5-Fu cells. BGC823/5–Fu-CSCs exhibited strong drug resistance to 5-Fu and high expression of ABC transporter genes MDR1 and MRP1 compared to CD44(-) cells. YQHY increased the inhibition and apoptosis rates to efficiently inhibit the drug resistance of BGC823/5–Fu-CSCs. Meanwhile, it suppressed the expression of MDR1 and MRP1 and restrained the activation of PI3K/Akt/Nrf2 signaling pathway. Finally, it was found that IGF-1 partially restored the activation of PI3K/Akt/Nrf2 pathway, alleviated the inhibition of MDR1 and MRP1, blocked the proliferation-inhibitory and apoptosis-promotion effects. YQHY and si-Nrf2 synergistically suppressed the MDR1/MRP1 expression and the drug resistance of BGC823/5–Fu-CSCs.

Conclusions

CD44 was a reliable GC stemness biomarker, and the high expression of ABC transporter genes MDR1 and MRP1 was an important feature of drug-resistant stem cells. YQHY inhibited the MDR1 and MRP1 expression via PI3K/Akt/Nrf2 pathway, thus reversing the drug resistance of BGC823/5–Fu-CSCs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13020-022-00647-y.

Inhibition of the Phospholipase Cε-c-Jun N-Terminal Kinase Axis Suppresses Glioma Stem Cell Properties

Glioma stem cells (GSCs), the cancer stem cells of glioblastoma multiforme (GBM), contribute to the malignancy of GBM due to their resistance to therapy and tumorigenic potential; therefore, the development of GSC-targeted therapies is urgently needed to improve the poor prognosis of GBM patients. The molecular mechanisms maintaining GSCs need to be elucidated in more detail for the development of GSC-targeted therapy. In comparison with patient-derived GSCs and their differentiated counterparts, we herein demonstrated for the first time that phospholipase C (PLC)ε was highly expressed in GSCs, in contrast to other PLC isoforms. A broad-spectrum PLC inhibitor suppressed the viability of GSCs, but not their stemness. Nevertheless, the knockdown of PLCε suppressed the survival of GSCs and induced cell death. The stem cell capacity of residual viable cells was also suppressed. Moreover, the survival of mice that were transplanted with PLCε knockdown-GSCs was longer than the control group. PLCε maintained the stemness of GSCs via the activation of JNK. The present study demonstrated for the first time that PLCε plays a critical role in maintaining the survival, stemness, and tumor initiation capacity of GSCs. Our study suggested that PLCε is a promising anti-GSC therapeutic target.

Cortisol inhibits lipopolysaccharide-induced inflammatory response in bovine endometrial stromal cells via NF-κB and MAPK signaling pathways

Bovine uterine infection is commonly caused by Escherichia coli (E. coli). Elevated concentrations of plasma cortisol have been reported in postpartum cows. However, the direct role of cortisol in the inflammatory response of bovine endometrial stromal cells (BESCs) remains unclear. Therefore, the aim of the study was to explore the regulatory effect of cortisol on lipopolysaccharide (LPS)-induced inflammatory response in BESCs. Both the primary and immortalized BESCs were used in this study. BESCs were treated with cortisol (5, 15, and 30 ng/mL) in the presence of LPS. The mRNA expression of inflammatory cytokines and chemokines was detected using RT-qPCR. Western blot and immunofluorescence were used to analyze the activation of the NF-κB and MAPK signaling pathways. The results revealed that cortisol downregulated the LPS-induced overexpression of interleukin(IL)-1β, IL-6, IL-8, TNF-α, COX-2, iNOS in BESCs. Moreover, cortisol inhibited LPS-induced phosphorylation levels of IκB, p65, ERK1/2, JNK and p38, and p65 nuclear translocation in BESCs. These results indicated that cortisol inhibited LPS-induced inflammatory response in BESCs, which may be mediated by suppressing the NF-κB and MAPK signaling pathways.

HDAC Class I Inhibitor Domatinostat Preferentially Targets Glioma Stem Cells over Their Differentiated Progeny

Cancer stem cells (CSCs) are in general characterized by higher resistance to cell death and cancer therapies than non-stem differentiated cancer cells. However, we and others have recently revealed using glioma stem cells (GSCs) as a model that, unexpectedly, CSCs have specific vulnerabilities that make them more sensitive to certain drugs compared with their differentiated counterparts. We aimed in this study to discover novel drugs targeting such Achilles’ heels of GSCs as anti-GSC drug candidates to be used for the treatment of glioblastoma, the most therapy-resistant form of brain tumors. Here we report that domatinostat (4SC-202), a class I HDAC inhibitor, is one such candidate. At concentrations where it showed no or minimal growth inhibitory effect on differentiated GSCs and normal cells, domatinostat effectively inhibited the growth of GSCs mainly by inducing apoptosis. Furthermore, GSCs that survived domatinostat treatment lost their self-renewal capacity. These results suggested that domatinostat is a unique drug that selectively eliminates GSCs not only physically by inducing cell death but also functionally by inhibiting their self-renewal. Our findings also imply that class I HDACs and/or LSD1, another target of domatinostat, may possibly have a specific role in the maintenance of GSCs and therefore could be an attractive target in the development of anti-GSC therapies.

Dexamethasone promotes breast cancer stem cells in obese and not lean mice

Obesity is highly prevalent in breast cancer patients and is associated with increased recurrence and breast cancer-specific mortality. Glucocorticoids (GC) are used as an adjuvant in cancer treatment and are associated with promoting breast cancer metastasis through activation of stemness-related pathways. Therefore, we utilized the synergetic allograft E0771 breast cancer model to investigate if treatment with GCs had differential effects on promoting cancer stem cells in lean and diet-induced obese mice. Indeed, both lean mice treated with dexamethasone and obese mice with no treatment had no effect on the ex vivo colony-forming ability, mammosphere formation, or aldehyde dehydrogenase (ALDH) bright subpopulation. However, treatment of obese mice with dexamethasone resulted in a significant increase in ex vivo colony formation, mammosphere formation, ALDH bright subpopulation, and expression of pluripotency transcription factors. GC transcriptionally regulated genes were not altered in the dexamethasone-treated groups compared to treatment controls. In summary, these results provide initial evidence that obesity presents a higher risk of GC-induced cancer stemness via non-genomic GC signaling which is of potential translational significance.

Advantages and drawbacks of dexamethasone in glioblastoma multiforme

The most widespread, malignant, and deadliest type of glial tumor is glioblastoma multiforme (GBM). Despite radiation, chemotherapy, and radical surgery, the median survival of afflicted individuals is about 12 months. Unfortunately, existing therapeutic interventions are abysmal. Dexamethasone (Dex), a synthetic glucocorticoid, has been used for many years to treat brain edema and inflammation caused by GBM. Several investigations have recently shown that Dex also exerts antitumoral effects against GBM. On the other hand, more recent disputed findings have questioned the long-held dogma of Dex treatment for GBM. Unfortunately, steroids are associated with various undesirable side effects, including severe immunosuppression and metabolic changes like hyperglycemia, which may impair the survival of GBM patients. Current ideas and concerns about Dex's effects on GBM cerebral edema, cell proliferation, migration, and its clinical outcomes were investigated in this study.

Outcomes of peri-operative glucocorticosteroid use in major pancreatic resections: a systematic review

BACKGROUND

There is increasing evidence that peri-operative glucocorticosteroid can ameliorate the systemic response following major surgery. Preliminary evidence suggests peri-operative usage of glucocorticosteroid may decrease post-operative complications. These positive associations have been observed in a range of different operations including intra-abdominal, thoracic, cardiac, and orthopaedic surgery. This review aims to investigate the impact of peri-operative glucocorticosteroid in major pancreatic resections.

METHODS

A systematic review based on a search in Medline and Embase databases was performed. PRISMA guidelines for systematic reviews were followed.

RESULTS

A total of five studies were analysed; three randomised controlled trials and two retrospective cohort studies. The total patient population was 1042. The glucocorticosteroids used were intravenous hydrocortisone or dexamethasone. Three studies reported significantly lower morbidity in the peri-operative glucocorticosteroid group. The number needed to treat to prevent one major complication with hydrocortisone is four patients. Two studies demonstrated that dexamethasone was associated with a statistically significantly improved median overall survival in pancreatic cancer.

CONCLUSION

This is the first systematic review conducted to investigate the significance of peri-operative glucocorticosteroid in patients undergoing pancreatic resection. This review shows a correlation of positive outcomes with the administration of glucocorticosteroid in the peri-operative setting following a major pancreatic resection.. More randomised clinical trials are required to confirm if this is a true effect, as it would have significant implications.

Targeting Cancer Stem Cells by Dietary Agents: An Important Therapeutic Strategy against Human Malignancies

As a multifactorial disease, treatment of cancer depends on understanding unique mechanisms involved in its progression. The cancer stem cells (CSCs) are responsible for tumor stemness and by enhancing colony formation, proliferation as well as metastasis, and these cells can also mediate resistance to therapy. Furthermore, the presence of CSCs leads to cancer recurrence and therefore their complete eradication can have immense therapeutic benefits. The present review focuses on targeting CSCs by natural products in cancer therapy. The growth and colony formation capacities of CSCs have been reported can be attenuated by the dietary agents. These compounds can induce apoptosis in CSCs and reduce tumor migration and invasion via EMT inhibition. A variety of molecular pathways including STAT3, Wnt/β-catenin, Sonic Hedgehog, Gli1 and NF-κB undergo down-regulation by dietary agents in suppressing CSC features. Upon exposure to natural agents, a significant decrease occurs in levels of CSC markers including CD44, CD133, ALDH1, Oct4 and Nanog to impair cancer stemness. Furthermore, CSC suppression by dietary agents can enhance sensitivity of tumors to chemotherapy and radiotherapy. In addition to in vitro studies, as well as experiments on the different preclinical models have shown capacity of natural products in suppressing cancer stemness. Furthermore, use of nanostructures for improving therapeutic impact of dietary agents is recommended to rapidly translate preclinical findings for clinical use.

Dexamethasone Sensitizes Cancer Stem Cells to Gemcitabine and 5-Fluorouracil by Increasing Reactive Oxygen Species Production through NRF2 Reduction

Cancer stem cells (CSCs) have high tumor-initiating capacity and are resistant to chemotherapeutic reagents; thus eliminating CSCs is essential to improving the prognosis. Recently, we reported that dexamethasone increases the effects of gemcitabine on pancreatic CSCs; however, the mechanism involved remains to be fully elucidated. In this study, we explored the role of reactive oxygen species (ROS) in the dexamethasone-induced chemosensitization of CSCs. Dexamethasone increased the growth-inhibitory effects of gemcitabine and 5-fluorouracil, whereas N-acetyl-cysteine, a ROS scavenger, abolished this effect. Although dexamethasone alone did not increase ROS levels, dexamethasone promoted the increase in ROS levels induced by gemcitabine and 5-fluorouracil. Dexamethasone treatment reduced the expression of NRF2, a key regulator of antioxidant responses, which was attenuated by siRNA-mediated knockdown of the glucocorticoid receptor. Furthermore, brusatol, a suppressor of NRF2, sensitized pancreatic CSCs to gemcitabine and 5-fluorouracil. Of note, essentially, the same mechanism was functional in ovarian and colon CSCs treated by the combination of dexamethasone and chemotherapeutic agents. Our study suggests that dexamethasone can sensitize CSCs to chemotherapeutic agents by promoting chemotherapy-induced ROS production through suppressing NRF2 expression.

JNK in Tumor Microenvironment: Present Findings and Challenges in Clinical Translation

Simple Summary

Stress-activated c-Jun N-terminal kinases (JNKs) are members of mitogen-activated protein kinases (MAPKs). Apart from having both tumor promoting and tumor suppressing roles in cancers due to its impact on apoptosis and autophagy pathways, JNK also plays complex roles in the heterogeneous tumor microenvironment (TME) and is involved in different tumorigenesis pathways. The JNK pathway influences various stressful and chronic inflammatory conditions along with different cell populations in TME. In this review, we aim to present the current knowledge of JNK-mediated processes in TME and the challenges in clinical translation.

Abstract

The c-Jun N-terminal kinases (JNKs) are a group of mitogen-activated protein kinases (MAPKs). JNK is mainly activated under stressful conditions or by inflammatory cytokines and has multiple downstream targets for mediating cell proliferation, differentiation, survival, apoptosis, and immune responses. JNK has been demonstrated to have both tumor promoting and tumor suppressing roles in different cancers depending on the focused pathway in each study. JNK also plays complex roles in the heterogeneous tumor microenvironment (TME). JNK is involved in different tumorigenesis pathways. TME closely relates with tumor development and consists of various stressful and chronic inflammatory conditions along with different cell populations, in which the JNK pathway may have various mediating roles. In this review, we aim to summarize the present knowledge of JNK-mediated processes in TME, including hypoxia, reactive oxygen species, inflammation, immune responses, angiogenesis, as well as the regulation of various cell populations within TME. This review also suggests future research directions for translating JNK modulation in pre-clinical findings to clinical benefits.

Novel Primary Human Cancer Stem-Like Cell Populations from Non-Small Cell Lung Cancer: Inhibition of Cell Survival by Targeting NF-κB and MYC Signaling

There is growing evidence that cancer stem cells (CSCs), a small subpopulation of self-renewal cancer cells, are responsible for tumor growth, treatment resistance, and cancer relapse and are thus of enormous clinical interest. Here, we aimed to isolate new CSC-like cells derived from human primary non-small cell lung cancer (NSCLC) specimens and to analyze the influence of different inhibitors of NF-κB and MYC signaling on cell survival. CSC-like cells were established from three squamous cell carcinomas (SCC) and three adenocarcinomas (AC) of the lung and were shown to express common CSC markers such as Prominin-1, CD44-antigen, and Nestin. Further, cells gave rise to spherical cancer organoids. Inhibition of MYC and NF-κB signaling using KJ-Pyr-9, dexamethasone, and pyrrolidinedithiocarbamate resulted in significant reductions in cell survival for SCC- and AC-derived cells. However, inhibition of the protein–protein interaction of MYC/NMYC proto-oncogenes with Myc-associated factor X (MAX) using KJ-Pyr-9 revealed the most promising survival-decreasing effects. Next to the establishment of six novel in vitro models for studying NSCLC-derived CSC-like populations, the presented investigations might provide new insights into potential novel therapies targeting NF-κB/MYC to improve clinical outcomes in NSCLC patients. Nevertheless, the full picture of downstream signaling still remains elusive.