Therapeutic Aspects and Molecular Targets of Autophagy to Control Pancreatic Cancer Management

USP1 promotes pancreatic cancer progression and autophagy by deubiquitinating ATG14

Pancreatic ductal adenocarcinoma (PDAC) is characterized by extremely poor prognosis, high mortality, and limited therapeutic strategy. Autophagy is hyperactivated in PDAC, and targeting autophagy is emerging as a promising therapeutic strategy. The dysfunction of deubiquitinase ubiquitin-specific peptidase 1 (USP1) results in tumorigenesis and chemotherapy resistance. However, little is known about how USP1 regulates autophagy and its mechanism in tumor progression and drug sensitivity in PDAC. In this study, we found USP1 elevated in pancreatic cancer and USP1 expression inversely correlated with overall survival. USP1 depletion inhibited cell proliferation, epithelial-mesenchymal transition, and migration in PDAC cells. Interestingly, USP1 knockdown or inhibition reduced autophagy initiation and autophagy flux. By screening of interacting protein using coimmunoprecipitation, we identified that USP1 interacted with ATG14 (autophagy-related gene 14) protein, acting as a core component in autophagy initiation. Furthermore, USP1 overexpression deubiquitinated and enhanced ATG14 protein stability by reduced binding ubiquitin levels, whereas USP1 inhibition promoted its proteasome-dependent degradation. Notably, USP1 depletion or a novel USP1 inhibitor I-138 dramatically delayed tumor growth in xenograft model. USP1 inhibitor synergistically enhanced the anticancer efficiency of cisplatin in PDAC cells. Collectively, our study identifies USP1 as the first deubiquitinase in the modulation of ATG14 deubiquitination and unveils a regulatory role for USP1 in autophagy and PDAC progression. Targeting USP1 using a selective inhibitor I-138 may provide an effective strategy for chemotherapy treatment and combating drug resistance in autophagy-activated pancreatic cancer.

Autophagy and the pancreas: Healthy and disease states

Macroautophagy/autophagy is an intracellular degradation pathway that has an important effect on both healthy and diseased pancreases. It protects the structure and function of the pancreas by maintaining organelle homeostasis and removing damaged organelles. A variety of pancreas-related diseases, such as diabetes, pancreatitis, and pancreatic cancer, are closely associated with autophagy. Genetic studies that address autophagy confirm this view. Loss of autophagy homeostasis (lack or overactivation) can lead to a series of adverse reactions, such as oxidative accumulation, increased inflammation, and cell death. There is growing evidence that stimulating or inhibiting autophagy is a potential therapeutic strategy for various pancreatic diseases. In this review, we discuss the multiple roles of autophagy in physiological and pathological conditions of the pancreas, including its role as a protective or pathogenic factor.

Sulforaphane regulates cell proliferation and induces apoptotic cell death mediated by ROS-cell cycle arrest in pancreatic cancer cells

Background

Pancreatic cancer (PC), sometimes referred to as pancreatic ductal adenocarcinoma (PDAC), is a major cause of global mortality from cancer. Pancreatic cancer is a very aggressive and devastating kind of cancer, characterized by limited options for therapy and low possibilities of survival. Sulforaphane (SFN), a naturally occurring sulfur-containing compound, is believed to possess anti-inflammatory, anti-obesity, and anti-cancer characteristics.

Objective

However, efficient preventative and treatment measures are essential and SFN has been studied for its ability to suppress pancreatic cancer cell proliferation and induce apoptosis.

Methods

Here, SFN induced cytotoxicity and apoptosis in PDAC cell lines such as MIA PaCa-2 and PANC-1 cells, as evaluated by cytotoxicity, colony formation, western blot analysis, fluorescence-activated cell sorting (FACS), reactive oxygen species (ROS) detection, caspase-3 activity assay, immunofluorescence assay, and mitochondrial membrane potential assay.

Results

In MIA PaCa-2 and PANC-1 cells, SFN inhibited cell survival and proliferation in a dose-dependent manner. The activation of caspase zymogens results in cleaved PARP and cleaved caspase-3, which is associated with an accumulation in the sub G1 phase. Furthermore, SFN increased ROS level and γH2A.X expression while decreasing mitochondrial membrane potential (ΔΨm). Notably, the ROS scavenger N-Acetyl-L-cysteine (NAC) was shown to reverse SFN-induced cytotoxicity and ROS level. Subsequently, SFN-induced cell cycle arrest and apoptosis induction as a Trojan horse to eliminate pancreatic cancer cells via ROS-mediated pathways were used to inhibit pancreatic cancer cells.

Conclusion

Collectively, our data demonstrates that SFN-induced cell death follows the apoptosis pathway, making it a viable target for therapeutic interventions against pancreatic cancer.

Advancements in Utilizing Natural Compounds for Modulating Autophagy in Liver Cancer: Molecular Mechanisms and Therapeutic Targets

Autophagy, an intrinsic catabolic mechanism that eliminates misfolded proteins, dysfunctional organelles, and lipid droplets, plays a vital function in energy balance and cytoplasmic quality control, in addition to maintaining cellular homeostasis. Liver cancer such as hepatocellular carcinoma (HCC) is one of the most common causes of cancer deaths globally and shows resistance to several anticancer drugs. Despite the rising incidence and poor prognosis of malignant HCC, the underlying molecular mechanisms driving this aggressive cancer remain unclear. Several natural compounds, such as phytochemicals of dietary and non-dietary origin, affect hepatocarcinogenesis signaling pathways in vitro and in vivo, which may help prevent and treat HCC cells. Current HCC cells treatments include chemotherapy, radiation, and surgery. However, these standard therapies have substantial side effects, and combination therapy enhances side effects for an acceptable therapeutic benefit. Therefore, there is a need to develop treatment strategies for HCC cells that are more efficacious and have fewer adverse effects. Multiple genetic and epigenetic factors are responsible for the HCC cells to become resistant to standard treatment. Autophagy contributes to maintain cellular homeostasis, which activates autophagy for biosynthesis and mitochondrial regulation and recycling. Therefore, modifying autophagic signaling would present a promising opportunity to identify novel therapies to treat HCC cells resistant to current standard treatments. This comprehensive review illustrates how natural compounds demonstrate their anti-hepatocellular carcinoma function through autophagy.

Clinical Evaluation of the Pancreatic Cancer Microenvironment: Opportunities and Challenges

Advances in our understanding of pancreatic ductal adenocarcinoma (PDAC) and its tumor microenvironment (TME) have the potential to transform treatment for the hundreds of thousands of patients who are diagnosed each year. Whereas the clinical assessment of cancer cell genetics has grown increasingly sophisticated and personalized, current protocols to evaluate the TME have lagged, despite evidence that the TME can be heterogeneous within and between patients. Here, we outline current protocols for PDAC diagnosis and management, review novel biomarkers, and highlight potential opportunities and challenges when evaluating the PDAC TME as we prepare to translate emerging TME-directed therapies to the clinic.

Recent Advances in Cellular Signaling Interplay between Redox Metabolism and Autophagy Modulation in Cancer: An Overview of Molecular Mechanisms and Therapeutic Interventions

Autophagy is a fundamental homeostatic process in which certain cellular components are ingested by double-membrane autophagosomes and then degraded to create energy or to maintain cellular homeostasis and survival. It is typically observed in nutrient-deprived cells as a survival mechanism. However, it has also been identified as a crucial process in maintaining cellular homeostasis and disease progression. Normal cellular metabolism produces reactive oxygen (ROS) and nitrogen species at low levels. However, increased production causes oxidative stress, which can lead to diabetes, cardiovascular diseases, neurological disorders, and cancer. It was recently shown that maintaining redox equilibrium via autophagy is critical for cellular responses to oxidative stress. However, little is understood about the molecular cancer processes that connect to the control of autophagy. In cancer cells, oncogenic mutations, carcinogens, and metabolic reprogramming cause increased ROS generation and oxidative stress. Recent studies have suggested that increased ROS generation activates survival pathways that promote cancer development and metastasis. Moreover, the relationship between metabolic programming and ROS in cancer cells is involved in redox homeostasis and the malignant phenotype. Currently, while the signaling events governing autophagy and how redox homeostasis affects signaling cascades are well understood, very little is known about molecular events related to autophagy. In this review, we focus on current knowledge about autophagy modulation and the role of redox metabolism to further the knowledge of oxidative stress and disease progression in cancer regulation. Therefore, this review focuses on understanding how oxidation/reduction events fine-tune autophagy to help understand how oxidative stress and autophagy govern cancer, either as processes leading to cell death or as survival strategies for maintaining redox homeostasis in cancer.

Recent Update and Drug Target in Molecular and Pharmacological Insights into Autophagy Modulation in Cancer Treatment and Future Progress

Recent evidence suggests that autophagy is a governed catabolic framework enabling the recycling of nutrients from injured organelles and other cellular constituents via a lysosomal breakdown. This mechanism has been associated with the development of various pathologic conditions, including cancer and neurological disorders; however, recently updated studies have indicated that autophagy plays a dual role in cancer, acting as a cytoprotective or cytotoxic mechanism. Numerous preclinical and clinical investigations have shown that inhibiting autophagy enhances an anticancer medicine's effectiveness in various malignancies. Autophagy antagonists, including chloroquine and hydroxychloroquine, have previously been authorized in clinical trials, encouraging the development of medication-combination therapies targeting the autophagic processes for cancer. In this review, we provide an update on the recent research examining the anticancer efficacy of combining drugs that activate cytoprotective autophagy with autophagy inhibitors. Additionally, we highlight the difficulties and progress toward using cytoprotective autophagy targeting as a cancer treatment strategy. Importantly, we must enable the use of suitable autophagy inhibitors and coadministration delivery systems in conjunction with anticancer agents. Therefore, this review briefly summarizes the general molecular process behind autophagy and its bifunctional role that is important in cancer suppression and in encouraging tumor growth and resistance to chemotherapy and metastasis regulation. We then emphasize how autophagy and cancer cells interacting with one another is a promising therapeutic target in cancer treatment.

Potential Therapeutic Implication of Herbal Medicine in Mitochondria-Mediated Oxidative Stress-Related Liver Diseases

Mitochondria are double-membrane organelles that play a role in ATP synthesis, calcium homeostasis, oxidation-reduction status, apoptosis, and inflammation. Several human disorders have been linked to mitochondrial dysfunction. It has been found that traditional therapeutic herbs are effective on alcoholic liver disease (ALD) and nonalcoholic fatty liver disease (NAFLD) which are leading causes of liver cirrhosis and hepatocellular carcinoma. The generation of reactive oxygen species (ROS) in response to oxidative stress is caused by mitochondrial dysfunction and is considered critical for treatment. The role of oxidative stress, lipid toxicity, and inflammation in NAFLD are well known. NAFLD is a chronic liver disease that commonly progresses to cirrhosis and chronic liver disease, and people with obesity, insulin resistance, diabetes, hyperlipidemia, and hypertension are at a higher risk of developing NAFLD. NAFLD is associated with a number of pathological factors, including insulin resistance, lipid metabolic dysfunction, oxidative stress, inflammation, apoptosis, and fibrosis. As a result, the improvement in steatosis and inflammation is enough to entice researchers to look into liver disease treatment. However, antioxidant treatment has not been very effective for liver disease. Additionally, it has been suggested that the beneficial effects of herbal medicines on immunity and inflammation are governed by various mechanisms for lipid metabolism and inflammation control. This review provided a summary of research on herbal medicines for the therapeutic implementation of mitochondria-mediated ROS production in liver disease as well as clinical applications through herbal medicine. In addition, the pathophysiology of common liver disorders such as ALD and NAFLD would be investigated in the role that mitochondria play in the process to open new therapeutic avenues in the management of patients with liver disease.