Targeting Oncogenic Nuclear Factor Kappa B Signaling with Redox-Active Agents for Cancer Treatment

The role of LOXL2 induced by glucose metabolism-activated NF-κB in maintaining drug resistance through EMT and cancer stemness in gemcitabine-resistant PDAC

Gemcitabine is considered a standard treatment for pancreatic cancer, but developing drug resistance greatly limits the effectiveness of chemotherapy and increases the rate of recurrence. Lysyl oxide-like 2 (LOXL2) is highly expressed in pancreatic cancer and is involved in carcinogenesis and EMT regulation. However, studies on the role of LOXL2 in drug resistance are limited. Here, we investigated the mechanism of LOXL2 induction and the effect of LOXL2 on EMT and CSC in gemcitabine-resistant pancreatic cancer. Glucose metabolism was activated in gemcitabine-resistant pancreatic cancer cells, and NF-κB signaling was regulated accordingly. Activated NF-κB directly induces transcription by binding to the promoters of LOXL2 and ZEB1. The EMT process was significantly inhibited by the coregulation of ZEB1 and LOXL2. In addition, LOXL2 inhibition reduced the expression of cancer stemness markers and stemness by regulating MAPK signaling activity. LOXL2 inhibits tumor growth of gemcitabine-resistant pancreatic cancer cells and increases the sensitivity to gemcitabine in mouse models. KEY MESSAGES: We identified a specific mechanism for inducing LOXL2 overexpression in gemcitabine-resistant pancreatic cancer. Taken together, our results suggest LOXL2 has an important regulatory role in maintaining gemcitabine resistance and may be an effective therapeutic target to treat pancreatic cancer.

Molecular mechanisms of microRNA-301a during tumor progression and metastasis

Cancer is known as one of the leading causes of human deaths globally. Late diagnosis is considered as one of the main reasons for the high mortality rate among cancer patients. Therefore, the introduction of early diagnostic tumor markers can improve the efficiency of therapeutic modalities. MicroRNAs (miRNAs) have a key role in regulation of cell proliferation and apoptosis. MiRNAs deregulation has been frequently reported during tumor progressions. Since, miRNAs have a high stability in body fluids; they can be used as the reliable non-invasive tumor markers. Here, we discussed the role of miR-301a during tumor progressions. MiR-301a mainly functions as an oncogene via the modulation of transcription factors, autophagy, epithelial-mesenchymal transition (EMT), and signaling pathways. This review paves the way to suggest miR-301a as a non-invasive marker for the early tumor diagnosis. MiR-301a can also be suggested as an effective target in cancer therapy.

Pyroptosis: A new insight of non-small-cell lung cancer treatment

Non-small cell lung cancer (NSCLC) has become one of the most common malignant tumors. Emerging evidence has shown that tumor resistance to apoptosis by damaging or bypassing apoptotic cell death is a major contributor to poor responses to therapy in patients with NSCLC. Pyroptosis is a new type of cytolytic and inflammatory programmed death distinct from apoptosis. Currently, pyroptosis has been reported to cause a strong inflammatory response and significant tumor suppression. It is considered a promising therapeutic strategy and prognosis for NSCLC. In this review, we summarized the characteristics of pyroptosis from its underlying basis and role in NSCLC, thereby providing the potential of pyroptosis as a therapeutic strategy and highlighting the challenges of activating pyroptosis in NSCLC treatment.

Xanthohumol: An underestimated, while potent and promising chemotherapeutic agent in cancer treatment

Today, there is a growing interest nowadays in the use of herbal substances as cancer therapeutic agents. Over recent years, Xanthohumol (XTL) has been brought out as a prenylated chalcone that is found in hops (Humulus lupulus) and beer. XTL is being investigated for its potential properties, and it has been found to have various biological effects, including anti-microbial, anti-viral, and immunomodulatory. Other than these biological effects, it has also been found that XTL exerts anti-tumor effects. In the beginning, XTL, by modulating cell signaling pathways, including ERK, AKT, NF-κB, AMPK, Wnt/β-catenin, and Notch signaling in cancer cells, inhibits tumor cell functions. Moreover, XTL, by inducing apoptotic pathways, either intrinsic or extrinsic, promotes cancer cell death and arrests the cell cycle. Furthermore, XTL inhibits metastasis, angiogenesis, cancer stemness, drug resistance, cell respiration, etc., which results in tumor aggressiveness inhibition. XTL has low solubility in water, and it has been hypothesized that some modifications, including biotinylation, can improve its pharmacogenetic characteristics. Additionally, XTL derivates such as dihydroXTL and tetrahydroXTL can be helpful for more anti-tumor activities. Using XTL with other anti-tumor agents is another approach to overcome tumor cell resistance. XTL or its derivatives, it is believed, might provide novel chemotherapeutic methods in future cancer therapy.

Integrin Signaling Shaping BTK-Inhibitor Resistance

Integrins are adhesion molecules that function as anchors in retaining tumor cells in supportive tissues and facilitating metastasis. Beta1 integrins are known to contribute to cell adhesion-mediated drug resistance in cancer. Very late antigen-4 (VLA-4), a CD49d/CD29 heterodimer, is a beta1 integrin implicated in therapy resistance in both solid tumors and haematological malignancies such as chronic lymphocytic leukemia (CLL). A complex inside-out signaling mechanism activates VLA-4, which might include several therapeutic targets for CLL. Treatment regimens for this disease have recently shifted towards novel agents targeting BCR signaling. Bruton’s tyrosine kinase (BTK) is a component of B cell receptor signaling and BTK inhibitors such as ibrutinib are highly successful; however, their limitations include indefinite drug administration, the development of therapy resistance, and toxicities. VLA-4 might be activated independently of BTK, resulting in an ongoing interaction of CD49d-expressing leukemic cells with their surrounding tissue, which may reduce the success of therapy with BTK inhibitors and increases the need for alternative therapies. In this context, we discuss the inside-out signaling cascade culminating in VLA-4 activation, consider the advantages and disadvantages of BTK inhibitors in CLL and elucidate the mechanisms behind cell adhesion-mediated drug resistance.

Nuclear factor-kappa B and effector molecules in photoaging

Nuclear factor-kappa B (NF-κB) has important but complex functions in the photoaging of the human skin. This protein complex is activated upon UV irradiation and plays a key role in the signalling pathway of the inflammatory cascade. NF-κB induces the expression of various proinflammatory cytokines, such as tumour necrosis factor (TNF) and interleukin-1 (IL-1). These proinflammatory cytokines can in turn stimulate the activation of NF-κB, forming a vicious cycle. These processes cause chronic inflammation and contribute to skin ageing. In addition, the activation of NF-κB upregulates the expression of matrix metalloproteinases (MMPs) and leads to the degradation of structural proteins in the dermis. NF-κB disrupts the barrier function of the skin under prolonged and repeated UV stimulations in these ways. Such activity causes chronic skin damage, followed by the formation of wrinkles, dryness, roughness, laxity, and other photoaging manifestations. This study on the NF-κB signalling pathway and effector molecules provides a new perspective to understand and prevent photoaging.

scInTime: A Computational Method Leveraging Single-Cell Trajectory and Gene Regulatory Networks to Identify Master Regulators of Cellular Differentiation

Trajectory inference (TI) or pseudotime analysis has dramatically extended the analytical framework of single-cell RNA-seq data, allowing regulatory genes contributing to cell differentiation and those involved in various dynamic cellular processes to be identified. However, most TI analysis procedures deal with individual genes independently while overlooking the regulatory relations between genes. Integrating information from gene regulatory networks (GRNs) at different pseudotime points may lead to more interpretable TI results. To this end, we introduce scInTime-an unsupervised machine learning framework coupling inferred trajectory with single-cell GRNs (scGRNs) to identify master regulatory genes. We validated the performance of our method by analyzing multiple scRNA-seq data sets. In each of the cases, top-ranking genes predicted by scInTime supported their functional relevance with corresponding signaling pathways, in line with the results of available functional studies. Overall results demonstrated that scInTime is a powerful tool to exploit pseudotime-series scGRNs, allowing for a clear interpretation of TI results toward more significant biological insights.

Antioxidants in Hops: Bioavailability, Health Effects and Perspectives for New Products

Hop plant (Humulus lupulus L.) has been used by humans for ages, presumably first as a herbal remedy, then in the manufacturing of different products, from which beer is the most largely consumed. Female hops cones have different useful chemical compounds, an important class being antioxidants, mainly polyphenols. This narrative review describes the main antioxidants in hops, their bioavailability and biological effects, and the results obtained by now in the primary and secondary prevention of several non-communicable diseases, such as the metabolic syndrome related diseases and oncology. This article presents in vitro and in vivo data in order to better understand what was accomplished in terms of knowledge and practice, and what needs to be clarified by additional studies, mainly regarding xantohumol and its derivates, as well as regarding the bitter acids of hops. The multiple protective effects found by different studies are hindered up to now by the low bioavailability of some of the main antioxidants in hops. However, there are new promising products with important health effects and perspectives of use as food supplements, in a market where consumers increasingly search for products originating directly from plants.

NF-κB pathway play a role in SCD1 deficiency-induced ceramide de novo synthesis

Stearoyl-CoA-desaturase 1 (SCD1) deficiency mediates apoptosis in colorectal cancer cells by promoting ceramide de novo synthesis. The mechanisms underlying the cross-talk between SCD1 and ceramide synthesis have not been explored. We treated colorectal cancer cells with an SCD1 inhibitor and examined the effects on gene expression, cell growth, and cellular lipid contents. The main effect of SCD1 inhibition on the fatty acid contents of colorectal cancer cells was a decrease in monounsaturated fatty acids (MUFAs). RNA sequencing (RNA-seq) showed that the most intense alteration of gene expression after SCD1 inhibition occurred in the NF-κB signaling pathway. Further experiments revealed that SCD1 inhibition resulted in increased levels of phosphorylated NF-κB p65 and increased nuclear translocation of NF-κB p65. Treatment with an NF-κB inhibitor eliminated several effects of SCD1 inhibition, mainly including overexpression of serine palmitoyltransferase1 (SPT1), elevation of dihydroceramide contents, and suppression of cell growth. Furthermore, treatment with supplemental oleate counteracted the SCD1-induced NF-κB activation and downstream effects. In summary, our data demonstrate that the NF-κB pathway plays a role in SCD1 deficiency-induced ceramide de novo synthesis in colorectal cancer cells, and that reduced MUFA levels contribute to the course.

Stable Epigenetic Programming of Effector and Central Memory CD4 T Cells Occurs Within 7 Days of Antigen Exposure In Vivo

T cell immunological memory is established within days of an infection, but little is known about the in vivo changes in gene regulatory networks accounting for their ability to respond more efficiently to secondary infections. To decipher the timing and nature of immunological memory we performed genome-wide analyses of epigenetic and transcriptional changes in a mouse model generating antigen-specific T cells. Epigenetic reprogramming for Th differentiation and memory T cell formation was already established by the peak of the T cell response after 7 days. The Th memory T cell program was associated with a gain of open chromatin regions, enriched for RUNX, ETS and T-bet motifs, which remained stable for 56 days. The epigenetic programs for both effector memory, associated with T-bet, and central memory, associated with TCF-1, were established in parallel. Memory T cell-specific regulatory elements were associated with greatly enhanced inducible Th1-biased responses during secondary exposures to antigen. Furthermore, memory T cells responded in vivo to re-exposure to antigen by rapidly reprograming the entire ETS factor gene regulatory network, by suppressing Ets1 and activating Etv6 expression. These data show that gene regulatory networks are epigenetically reprogrammed towards memory during infection, and undergo substantial changes upon re-stimulation.

Anti-Tumor Activity of Hypericum perforatum L. and Hyperforin through Modulation of Inflammatory Signaling, ROS Generation and Proton Dynamics

In this paper we review the mechanisms of the antitumor effects of Hypericum perforatum L. (St. John's wort, SJW) and its main active component hyperforin (HPF). SJW extract is commonly employed as antidepressant due to its ability to inhibit monoamine neurotransmitters re-uptake. Moreover, further biological properties make this vegetal extract very suitable for both prevention and treatment of several diseases, including cancer. Regular use of SJW reduces colorectal cancer risk in humans and prevents genotoxic effects of carcinogens in animal models. In established cancer, SJW and HPF can still exert therapeutic effects by their ability to downregulate inflammatory mediators and inhibit pro-survival kinases, angiogenic factors and extracellular matrix proteases, thereby counteracting tumor growth and spread. Remarkably, the mechanisms of action of SJW and HPF include their ability to decrease ROS production and restore pH imbalance in tumor cells. The SJW component HPF, due to its high lipophilicity and mild acidity, accumulates in membranes and acts as a protonophore that hinders inner mitochondrial membrane hyperpolarization, inhibiting mitochondrial ROS generation and consequently tumor cell proliferation. At the plasma membrane level, HPF prevents cytosol alkalization and extracellular acidification by allowing protons to re-enter the cells. These effects can revert or at least attenuate cancer cell phenotype, contributing to hamper proliferation, neo-angiogenesis and metastatic dissemination. Furthermore, several studies report that in tumor cells SJW and HPF, mainly at high concentrations, induce the mitochondrial apoptosis pathway, likely by collapsing the mitochondrial membrane potential. Based on these mechanisms, we highlight the SJW/HPF remarkable potentiality in cancer prevention and treatment.

Upregulation of miRNA‑301a‑3p promotes tumor progression in gastric cancer by suppressing NKRF and activating NF‑κB signaling

MicroRNA‑301a (miRNA/miR‑301a) and nuclear factor (NF)‑κB signaling play important roles in tumor invasion, migration and progression. However, the role of miRNA‑301a‑3p in human gastric cancer (GC), and specifically in the activation of NF‑κB signaling, remains unclear. The aim of the present study was to investigate miRNA‑301a‑3p expression in GC progression and the molecular mechanisms as regards the regulation of NF‑κB signaling. Reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) was used to detect miRNA‑301a‑3p expression in GC and paired normal tissues. The association between the expression of miRNA‑301a‑3p and patient pathological parameters and the prognosis of GC was statistically analyzed using an in situ hybridization (ISH) assay. An MTS assay and a Transwell assay were performed to evaluate the effects of miRNA‑301a‑3p on the proliferation, invasion and migration of GC cells. RT‑qPCR and western blot analysis were used to analyze the association between miRNA‑301a‑3p and nuclear factor‑κB repressing factor (NKRF) expression and the corresponding downstream NF‑κB signaling molecules. A luciferase assay was used to verify the target effect of miRNA‑301a‑3p and NKRF. It was found that miRNA‑301a‑3p expression was significantly higher in 30 cases of primary GC compared with matched normal tissues. Additionally, the ISH assay indicated that the high expression of miRNA‑301a‑3p in GC was associated with tumor invasion depth, lymph node metastasis, lymph node invasion and tumor metastasis stage. Patients whose tumors had a higher miRNA‑301a‑3p expression level exhibited a poorer prognosis. The in vitro assay indicated that miRNA‑301a‑3p affected the proliferative and invasive ability of GC cells by targeting the expression of NKRF, which then affected NF‑κB signaling. Therefore, it was hypothesize that miRNA‑301a‑3p promotes GC progression and affects the prognosis of patients with GC by targeting NKRF, which in turn, directly influences NF‑κB activation.

Xanthohumol, a prenylated flavonoid from Hops, exerts anticancer effects against gastric cancer in vitro

Xanthohumol (Xn), a prenylated flavonoid isolated from Hops (Humulus lupulus L.), has demonstrated potent anticancer activity in multiple types of cancer. However, the effect of Xn on gastric cancer (GC) remains unknown. The aim of the present study was to investigate the effect of Xn on GC cell proliferation, apoptosis and metastasis. It was observed that Xn decreased the viability of GC cells, with very low or no toxicity to normal gastric epithelial cells GES‑1 at a concentration of 1‑100 µM. The proliferation of AGS cells was inhibited by Xn, as indicated by the decreased number of EdU‑positive cells. Xn treatment increased the number of apoptotic cells, downregulated the expression of Bcl‑2 and upregulated the expression of Bax, suggesting induction of apoptosis. The results from the wound healing and Transwell assays indicated that Xn suppressed AGS cell metastasis. Moreover, Xn induced reactive oxygen species (ROS) overproduction and inhibited nuclear factor (NF)‑κB signaling in AGS cells, which was reversed by the ROS inhibitor N‑acetylcysteine (NAC). NAC suppressed the effect of Xn on the proliferation, apoptosis and metastasis of AGS cells. Taken together, these results suggest that Xn exerts anticancer effects against GC via induction of ROS production and subsequent inhibition of NF‑κB signaling. Therefore, Xn may be a promising candidate treatment against GC progression.

Clinicopathologic significance of Cyr61 and NF-κB p65 expression in colorectal adenocarcinoma

AIM

To investigate the expression of cysteine rich 61 (Cyr61) and nuclear factor-κB (NF-κB) p65 in colorectal adenocarcinoma, and to explore their relationship with clinicopathologic parameters and prognosis.

METHODS

Ninety-two cases of colorectal adenocarcinoma treated at Hubei Huanggang Central Hospital from May 2010 to December 2012 were collected. Immunohistochemistry and Western blot were used to detect the expression of Cyr61 and NF-κB p65 in colorectal cancer and tumor adjacent tissues. The correlation between the expression of Cyr61 and NF-κB p65 and clinicopathological features and prognosis of colorectal adenocarcinoma was analyzed.

RESULTS

Both immunohistochemical staining and Western blot showed that the expression of Cyr61 and NF-κB p65 proteins in colorectal cancer tissues was significantly higher than that in tumor adjacent tissues (t = 24.866, P <0.001; t = 45.508, P <0.001). The expression of Cyr61 and NF-κB p65 in colorectal cancer tissue was significantly correlated (χ² = 14.087, P < 0.001). The expression of Cyr61 in colorectal cancer tissues was significantly correlated with tumor diameter, depth of invasion, vascular invasion, and TNM stage (P < 0.05). The expression of NF-κB p65 in colorectal cancer tissues was significantly correlated with tumor diameter, lymph node metastasis, and TNM stage (P < 0.05). The 5-year overall survival rates of patients with high expression of Cyr61 or NF-κB p65 were 41.30% and 45.65%, respectively, which were significantly lower than those of patients with low expression of Cyr61 or NF-κB p65 (76.09% and 71.74%, respectively; HR = 0.341, 95%CI: 0.179-0.649, P = 0.001; HR = 0.465, 95%CI: 0.245-0.881, P = 0.019).

CONCLUSION

Cyr61 and NF-κB p65 proteins are highly expressed in colorectal cancer tissues, and high expression of Cyr61 and NF-κB p65 proteins is significantly associated with clinicopathologic parameters and prognosis in patients with colorectal cancer.