Selective killing of K-ras-transformed pancreatic cancer cells by targeting NAD(P)H oxidase

Roles of reactive oxygen species in inflammation and cancer

Reactive oxygen species (ROS) constitute a spectrum of oxygenic metabolites crucial in modulating pathological organism functions. Disruptions in ROS equilibrium span various diseases, and current insights suggest a dual role for ROS in tumorigenesis and the immune response within cancer. This review rigorously examines ROS production and its role in normal cells, elucidating the subsequent regulatory network in inflammation and cancer. Comprehensive synthesis details the documented impacts of ROS on diverse immune cells. Exploring the intricate relationship between ROS and cancer immunity, we highlight its influence on existing immunotherapies, including immune checkpoint blockade, chimeric antigen receptors, and cancer vaccines. Additionally, we underscore the promising prospects of utilizing ROS and targeting ROS modulators as novel immunotherapeutic interventions for cancer. This review discusses the complex interplay between ROS, inflammation, and tumorigenesis, emphasizing the multifaceted functions of ROS in both physiological and pathological conditions. It also underscores the potential implications of ROS in cancer immunotherapy and suggests future research directions, including the development of targeted therapies and precision oncology approaches. In summary, this review emphasizes the significance of understanding ROS-mediated mechanisms for advancing cancer therapy and developing personalized treatments.

Capsaicin: A chili pepper bioactive phytocompound with a potential role in suppressing cancer development and progression

Cancer profoundly influences morbidity and fatality rates worldwide. Patients often have dismal prognoses despite recent improvements in cancer therapy regimens. However, potent biomolecules derived from natural sources, including medicinal and dietary plants, contain biological and pharmacological properties to prevent and treat various human malignancies. Capsaicin is a bioactive phytocompound present in red hot chili peppers. Capsaicin has demonstrated many biological effects, including antioxidant, anti-inflammatory, antimicrobial, and anticarcinogenic capabilities. This review highlights the cellular and molecular pathways through which capsaicin exhibits antineoplastic activities. Our work also depicts the synergistic anticancer properties of capsaicin in conjunction with other natural bioactive components and approved anticancer drugs. Capsaicin inhibits proliferation in various cancerous cells, and its antineoplastic actions in numerous in vitro and in vivo carcinoma models impact oncogenesis, tumor-promoting and suppressor genes, and associated signaling pathways. Capsaicin alone or combined with other phytocompounds or approved antineoplastic drugs triggers cell cycle progression arrest, generating reactive oxygen species and disrupting mitochondrial membrane integrity, ultimately stimulating caspases and promoting death. Furthermore, capsaicin alone or in combination can promote apoptosis in carcinoma cells by enhancing the p53 and c-Myc gene expressions. In conclusion, capsaicin alone or in combination can have enormous potential for cancer prevention and intervention, but further high-quality studies are needed to firmly establish the clinical efficacy of this phytocompound.

Nicotinamide adenine dinucleotide phosphate oxidase in pancreatic diseases: Mechanisms and future perspectives

Pancreatitis and pancreatic cancer (PC) stand as the most worrisome ailments affecting the pancreas. Researchers have dedicated efforts to unraveling the mechanisms underlying these diseases, yet their true nature continues to elude their grasp. Within this realm, oxidative stress is often believed to play a causal and contributory role in the development of pancreatitis and PC. Excessive accumulation of reactive oxygen species (ROS) can cause oxidative stress, and the key enzyme responsible for inducing ROS production in cells is nicotinamide adenine dinucleotide phosphate hydrogen oxides (NOX). NOX contribute to pancreatic fibrosis and inflammation by generating ROS that injure acinar cells, activate pancreatic stellate cells, and mediate macrophage polarization. Excessive ROS production occurs during malignant transformation and pancreatic carcinogenesis, creating an oxidative microenvironment that can cause abnormal apoptosis, epithelial to mesenchymal transition and genomic instability. Therefore, understanding the role of NOX in pancreatic diseases contributes to a more in-depth exploration of the exact pathogenesis of these diseases. In this review, we aim to summarize the potential roles of NOX and its mechanism in pancreatic disorders, aiming to provide novel insights into understanding the mechanisms underlying these diseases.

Capsaicinoids and Their Effects on Cancer: The "Double-Edged Sword" Postulate from the Molecular Scale

Capsaicinoids are a unique chemical species resulting from a particular biosynthesis pathway of hot chilies (Capsicum spp.) that gives rise to 22 analogous compounds, all of which are TRPV1 agonists and, therefore, responsible for the pungency of Capsicum fruits. In addition to their human consumption, numerous ethnopharmacological uses of chili have emerged throughout history. Today, more than 25 years of basic research accredit a multifaceted bioactivity mainly to capsaicin, highlighting its antitumor properties mediated by cytotoxicity and immunological adjuvancy against at least 74 varieties of cancer, while non-cancer cells tend to have greater tolerance. However, despite the progress regarding the understanding of its mechanisms of action, the benefit and safety of capsaicinoids' pharmacological use remain subjects of discussion, since CAP also promotes epithelial-mesenchymal transition, in an ambivalence that has been referred to as "the double-edge sword". Here, we update the comparative discussion of relevant reports about capsaicinoids' bioactivity in a plethora of experimental models of cancer in terms of selectivity, efficacy, and safety. Through an integration of the underlying mechanisms, as well as inherent aspects of cancer biology, we propose mechanistic models regarding the dichotomy of their effects. Finally, we discuss a selection of in vivo evidence concerning capsaicinoids' immunomodulatory properties against cancer.

Pancreatic Stellate Cells and Metabolic Alteration: Physiology and Pathophysiology

Pancreatic stellate cells play a pivotal role in the development of pancreatic fibrosis. A wide variety of external stimuli can cause PSC activation accompanied by metabolic changes, which alters the tissue microenvironment by producing extracellular matrix proteins, cytokines, growth factors, and other mediators. Several metabolites aggravate fibrosis and inflammation by acting as key activating factors for PSCs. In other words, PSCs sense systemic metabolic changes. The detrimental effects of PSC activation on normal pancreatic cells, especially islet cells, further complicate metabolic imbalance through the dysregulation of glucose metabolism. PSC activation promotes cancer by altering the metabolism in pancreatic cancer cells, which collaborate with PSCs to efficiently adapt to environmental changes, promoting their growth and survival. This collaboration also contributes to the acquisition of chemoresistance. PSCs sequester chemotherapeutic agents and produce competing molecules as additional resistance mechanisms. The application of these metabolic targets for novel therapeutic strategies is currently being explored. This mini-review summarizes the role of PSCs in metabolic regulation of normal and cancerous cells.

Generation of Hydrogen Peroxide and Downstream Protein Kinase D1 Signaling Is a Common Feature of Inducers of Pancreatic Acinar-to-Ductal Metaplasia

Pancreatic acinar-to-ductal metaplasia (ADM) is a reversible process that occurs after pancreatic injury, but becomes permanent and leads to pancreatic lesions in the presence of an oncogenic mutation in KRAS,. While inflammatory macrophage-secreted chemokines, growth factors that activate epidermal growth factor receptor (EGFR) and oncogenic KRAS have been implicated in the induction of ADM, it is currently unclear whether a common underlying signaling mechanism exists that drives this process. In this study, we show that different inducers of ADM increase levels of hydrogen peroxide, most likely generated at the mitochondria, and upregulate the expression of Protein Kinase D1 (PKD1), a kinase that can be activated by hydrogen peroxide. PKD1 expression in acinar cells affects their survival and mediates ADM, which is in part due to the PKD1 target NF-κB. Overall, our data implicate ROS-PKD1 signaling as a common feature of different inducers of pancreatic ADM.

Short-term dietary restriction ameliorates brain injury after cardiac arrest by modulation of mitochondrial biogenesis and energy metabolism in rats

Background

Dietary restriction (DR) is a well-known intervention that increases lifespan and resistance to multiple forms of acute stress, including ischemia reperfusion injury. However, the effect of DR on neurological injury after cardiac arrest (CA) remains unknown.

Methods

The effect of short-term DR (one week of 70% reduced daily diet) on neurological injury was investigated in rats using an asphyxial CA model. The survival curve was obtained using Kaplan-Meier survival analysis. Serum S-100β levels were detected by enzyme linked immunosorbent assay. Cellular apoptosis and neuronal damage were assessed by terminal deoxyribonucleotide transferase dUTP nick end labeling assay and Nissl staining. The oxidative stress was evaluated by immunohistochemical staining of 8-hydroxy-2'-deoxyguanosine (8-OHdG). Mitochondrial biogenesis was examined by electron microscopy and mitochondrial DNA copy number determination. The protein expression was detected by western blot. The reactive oxygen species (ROS) and metabolite levels were measured by corresponding test kits.

Results

Short-term DR significantly improved 3-day survival, neurologic deficit scores (NDS) and decreased serum S-100β levels after CA. Short-term DR also significantly attenuated cellular apoptosis, neuronal damage and oxidative stress in the brain after CA. In addition, short-term DR increased mitochondrial biogenesis as well as brain PGC-1α and SIRT1 protein expression after CA. Moreover, short-term DR increased adenosine triphosphate, β-hydroxybutyrate, acetyl-CoA levels and nicotinamide adenine dinucleotide (NAD⁺)/reduced form of NAD⁺ (NADH) ratios as well as decreased serum lactate levels.

Conclusions

Reduction of oxidative stress, upregulation of mitochondrial biogenesis and increase of ketone body metabolism may play a crucial role in preserving neuronal function after CA under short-term DR.

Current updates on the role of reactive oxygen species in bladder cancer pathogenesis and therapeutics

Bladder cancer (BCa) is the fourth most common urological malignancy in the world, it has become the costliest cancer to manage due to its high rate of recurrence and lack of effective treatment modalities. As a natural byproduct of cellular metabolism, reactive oxygen species (ROS) have an important role in cell signaling and homeostasis. Although up-regulation of ROS is known to induce tumorigenesis, growing evidence suggests a number of agents that can selectively kill cancer cells through ROS induction. In particular, accumulation of ROS results in oxidative stress-induced apoptosis in cancer cells. So, ROS is a double-edged sword. A modest level of ROS is required for cancer cells to survive, whereas excessive levels kill them. This review summarizes the up-to-date findings of oxidative stress-regulated signaling pathways and transcription factors involved in the etiology and progression of BCa and explores the possible therapeutic implications of ROS regulators as therapeutic agents for BCa.

Redox-Mediated Mechanism of Chemoresistance in Cancer Cells

Cellular reactive oxygen species (ROS) status is stabilized by a balance of ROS generation and elimination called redox homeostasis. ROS is increased by activation of endoplasmic reticulum stress, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase family members and adenosine triphosphate (ATP) synthesis of mitochondria. Increased ROS is detoxified by superoxide dismutase, catalase, and peroxiredoxins. ROS has a role as a secondary messenger in signal transduction. Cancer cells induce fluctuations of redox homeostasis by variation of ROS regulated machinery, leading to increased tumorigenesis and chemoresistance. Redox-mediated mechanisms of chemoresistance include endoplasmic reticulum stress-mediated autophagy, increased cell cycle progression, and increased conversion to metastasis or cancer stem-like cells. This review discusses changes of the redox state in tumorigenesis and redox-mediated mechanisms involved in tolerance to chemotherapeutic drugs in cancer.

Phosphoinositide 3-Kinase Signaling Pathway in Pancreatic Ductal Adenocarcinoma Progression, Pathogenesis, and Therapeutics

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy characterized by its sudden manifestation, rapid progression, poor prognosis, and limited therapeutic options. Genetic alterations in key signaling pathways found in early pancreatic lesions are pivotal for the development and progression of pancreatic intraepithelial neoplastic lesions into invasive carcinomas. More than 90% of PDAC tumors harbor driver mutations in K-Ras that activate various downstream effector-signaling pathways, including the phosphoinositide-3-kinase (PI3K) pathway. The PI3K pathway also responds to stimuli from various growth factor receptors present on the cancer cell surface that, in turn, modulate downstream signaling cascades. Thus, the inositide signaling acts as a central node in the complex cellular signaling networks to impact cancer cell growth, motility, metabolism, and survival. Also, recent publications highlight the importance of PI3K signaling in stromal cells, whereby PI3K signaling modifies the tumor microenvironment to dictate disease outcome. The high incidence of mutations in the PI3K signaling cascade, accompanied by activation of parallel signaling pathways, makes PI3K a promising candidate for drug therapy. In this review, we describe the role of PI3K signaling in pancreatic cancer development and progression. We also discuss the crosstalk between PI3K and other major cellular signaling cascades, and potential therapeutic opportunities for targeting pancreatic ductal adenocarcinoma.

DHRS2 inhibits cell growth and motility in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is highly prevailing in Asia and it is ranked in the most aggressive squamous cell carcinomas. High-frequency loss of heterozygosity occurred in chromosome 14q11.2 in many tumors including ESCC, suggesting that one or more tumor-suppressor genes might exist within this region. In this study, we identified the tumor-suppressing role of DHRS2 (short-chain dehydrogenase/reductase family, member 2) at 14q11.2 in ESCCs. Downregulation of DHRS2 occurred in 30.8% of primary ESCC tumor tissues vs paired non-tumorous tissues. DHRS2 downregulation was associated significantly with ESCC invasion, lymph nodes metastasis and clinical staging (P<0.001). Survival analysis revealed that DHRS2 downregulation was significantly associated with worse outcome of patients with ESCC. In vitro and in vivo studies indicated that both DHRS2 variants could suppress cell proliferation and cell motility. Moreover, we demonstrated that DHRS2 could reduce reactive oxygen species and decrease nicotinamide adenine dinucleotide phosphate (oxidized/reduced), increase p53 stability and decrease Rb phosphorylation; it also decreased p38 mitogen-activated protein kinase phosphorylation and matrix metalloproteinase 2. In summary, these findings demonstrated that DHRS2 had an important part in ESCC development and progression.

The receptor for advanced glycation end products: A fuel to pancreatic cancer

The receptor for advanced glycation end products (RAGEs) was first illustrated in the year 1992. RAGE is a single-transmembrane and multi-ligand component of the immunoglobulin protein super family. The engagement of RAGE turns out to an establishment of numerous intracellular signalling mechanisms resulting in the progression and perpetuation of many types of cancer including, the pancreatic cancer. The present review primarily focuses on the multi-ligand activation of RAGEs leading to the downstream signalling cascade activation. The kick start of the RAGEs activation leads to the several anomalies and includes multiple types of cancers. The RAGE expression correlates well with the survival of pancreatic cancer cells leading to the myeloid response. RAGEs assist in the tumourogenesis which enhance and thrive to its fullest in the stressed tumour microenvironment. An improved perceptive of its involvement in pancreatic cancer may offer novel targets for tumour supervision and risk measurement.

Targeting reactive oxygen species in development and progression of pancreatic cancer

INTRODUCTION

Pancreatic ductal adenocarcinoma (PDA) is characterized by expression of oncogenic KRas which drives all aspects of tumorigenesis. Oncogenic KRas induces the formation of reactive oxygen species (ROS) which have been implicated in initiation and progression of PDA. To facilitate tumor promoting levels and to avoid oncogene-induced senescence or cytotoxicity, ROS homeostasis in PDA cells is balanced by additional up-regulation of antioxidant systems. Areas covered: We examine the sources of ROS in PDA, the mechanisms by which ROS homeostasis is maintained, and the biological consequences of ROS in PDA. Additionally, we discuss the potential mechanisms for targeting ROS homoeostasis as a point of therapeutic intervention. An extensive review of the relevant literature as it relates to the topic was conducted using PubMed. Expert commentary: Even though oncogenic mutations in the KRAS gene have been detected in over 95% of human pancreatic adenocarcinoma, targeting its gene product, KRas, has been difficult. The dependency of PDA cells on balancing ROS homeostasis could be an angle for new prevention or treatment strategies. These include use of antioxidants to prevent formation or progression of precancerous lesions, or methods to increase ROS in tumor cells to toxic levels.

Harnessing the Therapeutic Potential of Capsaicin and Its Analogues in Pain and Other Diseases

Capsaicin is the most predominant and naturally occurring alkamide found in Capsicum fruits. Since its discovery in the 19th century, the therapeutic roles of capsaicin have been well characterized. The potential applications of capsaicin range from food flavorings to therapeutics. Indeed, capsaicin and few of its analogues have featured in clinical research covered by more than a thousand patents. Previous records suggest pleiotropic pharmacological activities of capsaicin such as an analgesic, anti-obesity, anti-pruritic, anti-inflammatory, anti-apoptotic, anti-cancer, anti-oxidant, and neuro-protective functions. Moreover, emerging data indicate its clinical significance in treating vascular-related diseases, metabolic syndrome, and gastro-protective effects. The dearth of potent drugs for management of such disorders necessitates the urge for further research into the pharmacological aspects of capsaicin. This review summarizes the historical background, source, structure and analogues of capsaicin, and capsaicin-triggered TRPV1 signaling and desensitization processes. In particular, we will focus on the therapeutic roles of capsaicin and its analogues in both normal and pathophysiological conditions.

Melatonin overcomes gemcitabine resistance in pancreatic ductal adenocarcinoma by abrogating nuclear factor-κB activation

Constitutive activation and gemcitabine induction of nuclear factor-κB (NF-κB) contribute to the aggressive behavior and chemotherapeutic resistance of pancreatic ductal adenocarcinoma (PDAC). Thus, targeting the NF-κB pathway has proven an insurmountable challenge for PDAC therapy. In this study, we investigated whether the inhibition of NF-κB signaling pathway by melatonin might lead to tumor suppression and overcome gemcitabine resistance in pancreatic tumors. Our results showed that melatonin inhibited activities of NF-κB by suppressing IκBα phosphorylation and decreased the expression of NF-κB response genes in MiaPaCa-2, AsPc-1, Panc-28 cells and gemcitabine resistance MiaPaCa-2/GR cells. Moreover, melatonin not only inhibited cell proliferation and invasion in a receptor-independent manner, but also enhanced gemcitabine cytotoxicity at pharmacologic concentrations in these PDAC cells. In vivo, the mice treated with both agents experienced a larger reduction in tumor burden than the single drug-treated groups in an orthotopic xenograft mouse model. Taken together, these results indicate that melatonin inhibits proliferation and invasion of PDAC cells and overcomes gemcitabine resistance of pancreatic tumors through NF-κB inhibition. Our findings therefore provide novel preclinical knowledge about melatonin inhibition of NF-κB in PDAC and suggest that melatonin should be investigated clinically, alone or in combination with gemcitabine for PDAC treatment.