Gemcitabine/cannabinoid combination triggers autophagy in pancreatic cancer cells through a ROS-mediated mechanism

A comprehensive review on phytochemicals in the treatment and prevention of pancreatic cancer: Focusing on their mechanism of action

Background and Aims

Pancreatic cancer develops in the normal tissues of the pancreas from malignant cells. The chance of recovery is not good, and the chance of survival 5 years following diagnosis is quite low. Pancreatic cancer treatment strategies such as radiotherapy and chemotherapy had relatively low success rates. Therefore, the present study aims to explore new therapies for treating pancreatic cancer.

Methods

The present study searched for information about pancreatic cancer pathophysiology, available treatment options; and their comparative benefits and challenges. Aiming to identify potential alternative therapeutics, this comprehensive review analyzed information from renowned databases such as Scopus, PubMed, and Google Scholar.

Results

In recent years, there has been a rise in interest in the possibility that natural compounds could be used as treatments for cancer. Cannabinoids, curcumin, quercetin, resveratrol, and triptolide are some of the anticancer phytochemicals now used to manage pancreatic cancer. The above compounds are utilized by inhibiting or stimulating biological pathways such as apoptosis, autophagy, cell growth inhibition or reduction, oxidative stress, epithelial-mesenchymal transformation, and increased resistance to chemotherapeutic drugs in the management of pancreatic cancer.

Conclusion

Right now, surgery is the only therapeutic option for patients with pancreatic cancer. However, most people who get sick have been diagnosed too late to benefit from potentially effective surgery. Alternative medications, like natural compounds and herbal medicines, are promising complementary therapies for pancreatic cancer. Therefore, we recommend large-scale standardized clinical research for the investigation of natural compounds to ensure their consistency and comparability in pancreatic cancer treatment.

HMGB1/RAGE axis in tumor development: unraveling its significance

High mobility group protein 1 (HMGB1) plays a complex role in tumor biology. When released into the extracellular space, it binds to the receptor for advanced glycation end products (RAGE) located on the cell membrane, playing an important role in tumor development by regulating a number of biological processes and signal pathways. In this review, we outline the multifaceted functions of the HMGB1/RAGE axis, which encompasses tumor cell proliferation, apoptosis, autophagy, metastasis, and angiogenesis. This axis is instrumental in tumor progression, promoting tumor cell proliferation, autophagy, metastasis, and angiogenesis while inhibiting apoptosis, through pivotal signaling pathways, including MAPK, NF-κB, PI3K/AKT, ERK, and STAT3. Notably, small molecules, such as miRNA-218, ethyl pyruvate (EP), and glycyrrhizin exhibit the ability to inhibit the HMGB1/RAGE axis, restraining tumor development. Therefore, a deeper understanding of the mechanisms of the HMGB1/RAGE axis in tumors is of great importance, and the development of inhibitors targeting this axis warrants further exploration.

CB2 agonist mitigates cocaine-induced reinstatement of place preference and modulates the inflammatory response in mice

Chronic exposure to cocaine is known to have profound effects on the brain, leading to the dysregulation of inflammatory signalling pathways, the activation of microglia, and the manifestation of cognitive and motivational behavioural impairments. The endocannabinoid system has emerged as a potential mediator of cocaine's deleterious effects. In this study, we sought to investigate the therapeutic potential of the cannabinoid CB2 receptor agonist, JWH-133, in mitigating cocaine-induced inflammation and associated motivational behavioural alterations in an in vivo model. Our research uncovered compelling evidence that JWH-133, a selective CB2 receptor agonist, exerts a significant dampening effect on the reinstatement of cocaine-induced conditioned place preference. This effect was accompanied by notable changes in the neurobiological landscape. Specifically, JWH-133 administration was found to upregulate Δ-FOSB expression in the nucleus accumbens (Nac), elevate CX3CL1 levels in both the ventral tegmental area and prefrontal cortex (PFC), and concurrently reduce IL-1β expression in the PFC and NAc among cocaine-treated animals. These findings highlight the modulatory role of CB2 cannabinoid receptor activation in altering the reward-seeking behaviour induced by cocaine. Moreover, they shed light on the intricate interplay between the endocannabinoid system and cocaine-induced neurobiological changes, paving the way for potential therapeutic interventions targeting CB2 receptors in the context of cocaine addiction and associated behavioural deficits.

Evaluating the Mechanism of Cell Death in Melanoma Induced by the Cannabis Extract PHEC-66

Research suggests the potential of using cannabinoid-derived compounds to function as anticancer agents against melanoma cells. Our recent study highlighted the remarkable in vitro anticancer effects of PHEC-66, an extract from Cannabis sativa, on the MM418-C1, MM329, and MM96L melanoma cell lines. However, the complete molecular mechanism behind this action remains to be elucidated. This study aims to unravel how PHEC-66 brings about its antiproliferative impact on these cell lines, utilising diverse techniques such as real-time polymerase chain reaction (qPCR), assays to assess the inhibition of CB1 and CB2 receptors, measurement of reactive oxygen species (ROS), apoptosis assays, and fluorescence-activated cell sorting (FACS) for apoptosis and cell cycle analysis. The outcomes obtained from this study suggest that PHEC-66 triggers apoptosis in these melanoma cell lines by increasing the expression of pro-apoptotic markers (BAX mRNA) while concurrently reducing the expression of anti-apoptotic markers (Bcl-2 mRNA). Additionally, PHEC-66 induces DNA fragmentation, halting cell progression at the G1 cell cycle checkpoint and substantially elevating intracellular ROS levels. These findings imply that PHEC-66 might have potential as an adjuvant therapy in the treatment of malignant melanoma. However, it is essential to conduct further preclinical investigations to delve deeper into its potential and efficacy.

The Anticancer Potential of Kaempferol: A Systematic Review Based on In Vitro Studies

Given the heterogeneity of different malignant processes, planning cancer treatment is challenging. According to recent studies, natural products are likely to be effective in cancer prevention and treatment. Among bioactive flavonoids found in fruits and vegetables, kaempferol (KMP) is known for its anti-inflammatory, antioxidant, and anticancer properties. This systematic review aims to highlight the potential therapeutic effects of KMP on different types of solid malignant tumors. This review was conducted following the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines. Searches were performed in EMBASE, Medline/PubMed, Cochrane Collaboration Library, Science Direct, Scopus, and Google Scholar. After the application of study criteria, 64 studies were included. In vitro experiments demonstrated that KMP exerts antitumor effects by controlling tumor cell cycle progression, proliferation, apoptosis, migration, and invasion, as well as by inhibiting angiogenesis. KMP was also able to inhibit important markers that regulate epithelial-mesenchymal transition and enhanced the sensitivity of cancer cells to traditional drugs used in chemotherapy, including cisplatin and 5-fluorouracil. This flavonoid is a promising therapeutic compound and its combination with current anticancer agents, including targeted drugs, may potentially produce more effective and predictable results.

ISG15 Promotes Progression and Gemcitabine Resistance of Pancreatic Cancer Cells Through ATG7

Chemoresistance is an obstacle of improving pancreatic cancer (PC) prognosis. However, the biological function of ISG15 in PC and whether it correlates with the resistance to chemotherapy are still unknown. Here, we aimed to reveal the clinical significance of ISG15 in PC and its regulatory mechanism in cancer progression and resistance to therapy. The level of ISG15, a protein involved in post-translational modifications, is elevated in PC tissues. Clinically, higher ISG15 expression correlates with higher PC grades, stronger resistance to treatment and poorer prognosis. Moreover, ISG15 promotes the proliferation, migration, invasion, colony formation of PC cells and resistance to Gemcitabine, a classic chemotherapeutics for PC, both in vitro and in vivo. ISG15 promotes progression and resistance to therapy in PC cells by binding to ATG7, reducing its degradation, and thereby leading to enhanced autophagy in PC cells. ISG15 may be used as both a potential diagnosis marker and sensitizer for chemotherapeutics such as Gemcitabine during PC intervention.

Acquired and intrinsic gemcitabine resistance in pancreatic cancer therapy: Environmental factors, molecular profile and drug/nanotherapeutic approaches

A high number of cancer patients around the world rely on gemcitabine (GEM) for chemotherapy. During local metastasis of cancers, surgery is beneficial for therapy, but dissemination in distant organs leads to using chemotherapy alone or in combination with surgery to prevent cancer recurrence. Therapy failure can be observed as a result of GEM resistance, threatening life of pancreatic cancer (PC) patients. The mortality and morbidity of PC in contrast to other tumors are increasing. GEM chemotherapy is widely utilized for PC suppression, but resistance has encountered its therapeutic impacts. The purpose of current review is to bring a broad concept about role of biological mechanisms and pathways in the development of GEM resistance in PC and then, therapeutic strategies based on using drugs or nanostructures for overcoming chemoresistance. Dysregulation of the epigenetic factors especially non-coding RNA transcripts can cause development of GEM resistance in PC and miRNA transfection or using genetic tools such as siRNA for modulating expression level of these factors for changing GEM resistance are suggested. The overexpression of anti-apoptotic proteins and survival genes can contribute to GEM resistance in PC. Moreover, supportive autophagy inhibits apoptosis and stimulates GEM resistance in PC cells. Increase in metabolism, glycolysis induction and epithelial-mesenchymal transition (EMT) stimulation are considered as other factors participating in GEM resistance in PC. Drugs can suppress tumorigenesis in PC and inhibit survival factors and pathways in increasing GEM sensitivity in PC. More importantly, nanoparticles can increase pharmacokinetic profile of GEM and promote its blood circulation and accumulation in cancer site. Nanoparticles mediate delivery of GEM with genes and drugs to suppress tumorigenesis in PC and increase drug sensitivity. The basic research displays significant connection among dysregulated pathways and GEM resistance, but the lack of clinical application is a drawback that can be responded in future.

Cannabinoid receptor 2 (CB2) agonists and L-arginine ameliorate diabetic nephropathy in rats by suppressing inflammation and fibrosis through NF-κβ pathway

Diabetic nephropathy (DN) is a condition that leads to end-stage chronic kidney disease characterized by inflammation and a deficiency of nitric oxide (NO). Cannabinoid receptor (CB2) activation by specific agonist reduces nuclear factor kappa beta (NF-κβ) expression. Beta caryophyllene (BCP), a natural CB2 receptor activator, protects kidney function in several diseases. L-Arginine (LA) modulates several physiological processes by donating nitric oxide (NO). Hence, we tested a novel BCP-LA combination to treat DN and investigated its molecular mechanisms. BCP, LA, and combinations of both were evaluated in LPS-induced RAW 264.7 macrophage inflammation as well as in streptozotocin (55 mg/kg)-induced diabetes in SD rats. Diabetic rats were administered 200 mg/kg of BCP, 100 mg/kg of LA, and combination of both orally for 28 days. Biochemical markers and inflammatory cytokines were assessed in plasma; also, kidney tissue was examined for renal oxidative stress injury, NF-κβ expression, and histology. After 28 days of treatment, BCP and LA combination significantly lowered plasma glucose levels than the disease control group. BCP and LA also normalized renal markers and oxidative stress of diabetic rats. Plasma and RAW macrophage cell lines showed reduced levels of IL-6 and TNF-α (P < 0.001). Histopathological evaluations revealed that BCP and LA together decreased renal fibrosis and collagen deposition also improved nephrotic indices. Meanwhile, the effect of BCP and LA together significantly reduced the NF-κβ (P < 0.01) against diabetic rats. These results indicate that the innovative regimen BCP with LA may be a therapeutic treatment for DN, as it protects kidney tissue from diabetes via NF-κβ inhibition.

Rationalizing a prospective coupling effect of cannabinoids with the current pharmacotherapy for melanoma treatment

Melanoma is one of the leading fatal forms of cancer, yet from a treatment perspective, we have minimal control over its reoccurrence and resistance to current pharmacotherapies. The endocannabinoid system (ECS) has recently been accepted as a multifaceted homeostatic regulator, influencing various physiological processes across different biological compartments, including the skin. This review presents an overview of the pathophysiology of melanoma, current pharmacotherapy used for treatment, and the challenges associated with the different pharmacological approaches. Furthermore, it highlights the utility of cannabinoids as an additive remedy for melanoma by restoring the balance between downregulated immunomodulatory pathways and elevated inflammatory cytokines during chronic skin conditions as one of the suggested critical approaches in treating this immunogenic tumor. This article is categorized under: Cancer > Molecular and Cellular Physiology.

In Vitro Evidence of Selective Pro-Apoptotic Action of the Pure Cannabidiol and Cannabidiol-Rich Extract

Plant cannabinoids, secondary metabolites of species belonging to the Cannabis genus, can mimic the endocannabinoids' action and exert biological effects. Considering the contribution of the endocannabinoid system in cell cycle and apoptotic regulation, there is an interest in exploring the potential anti-cancer activities of natural and synthetic cannabinoids. Cannabidiol (CBD), an abundant plant cannabinoid, reveals a low affinity to cannabinoid receptors and, contrary to various cannabinoids, lacks psychoactive action. Here, we present the in vitro assessment of the pro-apoptototic potential of CBD-rich extracts of Cannabis sativa L. (eCBD) compared to purified CBD (pCBD). As demonstrated, both eCBD and pCBD decreased the viability of breast cancer cell line MDA-MB-231 and human prostate cancer cell line PC-3 in a concentration-dependent fashion. Endoplasmic reticulum stress-related apoptosis and morphological changes were induced only in low-serum conditions. Moreover, the effects of eCDB and pCDB were also assessed in non-malignant cell lines (MCF-10A and PNT2) with no alterations of viability noted, ultimately suggesting a selective action of CBD in tumor cells. The results suggest the possible involvement of reactive oxygen species in the response mechanism to eCBD and pCBD, but no clear pattern was observed. We also demonstrated significant changes in gene expression involved in apoptosis and cell cycle control upon extract treatment. Altogether, our study shows the potential of eCBD and pCBD as novel pro-apoptototic agents that can be considered promising in future preclinical and clinical testing.

Iron-Dependent Cell Death: A New Treatment Approach against Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a devastating tumor type where a very high proportion of people diagnosed end up dying from cancer. Surgical resection is an option for only about 20% of patients, where the 5-year survival increase ranges from 10 to 25%. In addition to surgical resection, there are adjuvant chemotherapy schemes, such as FOLFIRINOX (a mix of Irinotecan, oxaliplatin, 5-Fluorouraci and leucovorin) or gemcitabine-based treatment. These last two drugs have been compared in the NAPOLI-3 clinical trial, and the NALIRIFOX arm was found to have a higher overall survival (OS) (11.1 months vs. 9.2 months). Despite these exciting improvements, PDAC still has no effective treatment. An interesting approach would be to drive ferroptosis in PDAC cells. A non-apoptotic reactive oxygen species (ROS)-dependent cell death, ferroptosis was first described by Dixon et al. in 2012. ROS are constantly produced in the tumor cell due to high cell metabolism, which is even higher when exposed to chemotherapy. Tumor cells have detoxifying mechanisms, such as Mn-SOD or the GSH-GPX system. However, when a threshold of ROS is exceeded in the tumor cell, the cell's antioxidant systems are overwhelmed, resulting in lipid peroxidation and, ultimately, ferroptosis. In this review, we point out ferroptosis as an approach to consider in PDAC and propose that altering the cellular ROS balance by combining oxidizing agents or with inhibitors of the main cellular detoxifiers triggers ferroptosis in PDAC.

Active Autophagy Is Associated with Favorable Outcome in Patients with Surgically Resected Cholangiocarcinoma

Data on the impact of autophagy in primary cholangiocarcinoma (CCA) remain scarce. Here, we therefore investigated the role of active autophagy and its impact on survival in CCA patients. All CCA patients who underwent surgical resection with curative intent between 08/2005 and 12/2021 at University Hospital Frankfurt were evaluated. Autophagic key proteins were studied by immunohistochemistry. iCCA processed for gene expression profiling of immune-exhaustion gene sets was used for an autophagy approach in silico. Active autophagy was present in 23.3% of the 172 CCA patients. Kaplan-Meier curves revealed median OS of 68.4 months (95% CI = 46.9-89.9 months) and 32.7 months (95% CI = 23.6-41.8 months) for active and non-active autophagy, respectively (p ≤ 0.001). In multivariate analysis, absence of active autophagy (HR = 2, 95% CI = 1.1-3.5, p = 0.015) was an independent risk factor for OS. Differential-expression profiling revealed significantly upregulated histone deacetylases (HDAC) mRNA in patients showing non-active autophagy. In line with this, pan-acetylated lysine was significantly more prominent in CCA patients with ongoing autophagy (p = 0.005). Our findings strengthen the role of active autophagy as a prognostically relevant marker and a potential therapeutic target.

Should gastroenterologists prescribe cannabis? The highs, the lows and the unknowns

Cannabis, commonly known as marijuana, is a drug extracted from the Cannabis plant known for its psychotropic and medicinal properties. It has been used for healing purposes during ancient times, although its psychoactive components led to its restricted use in medicine. Nonetheless, cannabis is found to have modulatory effects on the endocannabinoid system exhibiting its medicinal role in the gastrointestinal (GI) system. Emerging animal and human studies demonstrate the influential effects of cannabis on a variety of GI diseases including inflammatory bowel disease, motility disorders and GI malignancies. It also has a regulatory role in GI symptoms including nausea and vomiting, anorexia, weight gain, abdominal pain, among others. However, both its acute and chronic use can lead to undesirable side effects such as dependency and addiction, cognitive impairment and cannabinoid hyperemesis syndrome. We will discuss the role of cannabis in the GI system as well as dosing strategies to help guide gastroenterologists to assess its efficacy and provide patient counseling before prescription of medical marijuana.

Compound 275# Induces Mitochondria-Mediated Apoptosis and Autophagy Initiation in Colorectal Cancer Cells through an Accumulation of Intracellular ROS

Colorectal cancer (CRC) is the most common intestinal malignancy, and nearly 70% of patients with this cancer develop metastatic disease. In the present study, we synthesized a novel compound, termed N-(3-(5,7-dimethylbenzo [d]oxazol-2-yl)phenyl)-5-nitrofuran-2-carboxamide (compound 275#), and found that it exhibits antiproliferative capability in suppressing the proliferation and growth of CRC cell lines. Furthermore, compound 275# triggered caspase 3-mediated intrinsic apoptosis of mitochondria and autophagy initiation. An investigation of the molecular mechanisms demonstrated that compound 275# induced intrinsic apoptosis, and autophagy initiation was largely mediated by increasing the levels of the intracellular accumulation of reactive oxygen species (ROS) in CRC cells. Taken together, these data suggest that ROS accumulation after treatment with compound 275# leads to mitochondria-mediated apoptosis and autophagy activation, highlighting the potential of compound 275# as a novel therapeutic agent for the treatment of CRC.

Potential, Limitations and Risks of Cannabis-Derived Products in Cancer Treatment

The application of cannabis products in oncology receives interest, especially from patients. Despite the plethora of research data available, the added value in curative or palliative cancer care and the possible risks involved are insufficiently proven and therefore a matter of debate. We aim to give a recommendation on the position of cannabis products in clinical oncology by assessing recent literature. Various types of cannabis products, characteristics, quality and pharmacology are discussed. Standardisation is essential for reliable and reproducible quality. The oromucosal/sublingual route of administration is preferred over inhalation and drinking tea. Cannabinoids may inhibit efflux transporters and drug-metabolising enzymes, possibly inducing pharmacokinetic interactions with anticancer drugs being substrates for these proteins. This may enhance the cytostatic effect and/or drug-related adverse effects. Reversely, it may enable dose reduction. Similar interactions are likely with drugs used for symptom management treating pain, nausea, vomiting and anorexia. Cannabis products are usually well tolerated and may improve the quality of life of patients with cancer (although not unambiguously proven). The combination with immunotherapy seems undesirable because of the immunosuppressive action of cannabinoids. Further clinical research is warranted to scientifically support (refraining from) using cannabis products in patients with cancer.

Development and validation of a sensitive assay for the quantification of arachidonoylcyclopropylamide (ACPA) in cell culture by LC–MS/MS

Synthetic and natural cannabinoid derivatives are highly investigated as drug candidates due to their antinociceptive, antiepileptic and anticancer potential. Arachidonoylcyclopropylamide (ACPA) is a synthetic cannabinoid with antiproliferative and apoptotic effects on non-small cell lung cancer and pancreatic and endometrial carcinoma. Thus, ACPA has a great potential for being used as an anticancer drug for epithelial cancers. Therefore, determining the levels of ACPA in biological fluids, cells, tissues and pharmaceutical dosage forms is crucial in monitoring the effects of various pharmacological, physiological and pathological stimuli on biological systems. However, the challenge in the quantification of ACPA is its short half-life and lack of UV signal. Therefore, we developed a liquid chromatography-tandem mass spectrometric (LC–MS/MS) method for sensitive and selective quantification of ACPA in cell culture medium and intracellular matrix. Multiple reaction monitoring in the positive ionization mode was used for detection with 344 → 203 m/z transitions. The separation of ACPA was performed on C18 column (50 × 3.0 mm, 2.1 μm) with the mobile phase run in the gradient mode with 0.1% formic acid (FA) in water and 0.1% FA in acetonitrile at a flow rate of 0.3 ml/min. The assay was linear in the concentration range of 1.8–1000 ng/mL (r = 0.999). The validation studies revealed that the method was linear, sensitive, accurate, precise, selective, repeatable, robust and rugged. Finally, the developed method was applied to quantify ACPA in cell culture medium and intracellular matrix.

Synthesis and Characterization of the Diastereomers of HHC and H4CBD

The characterization of any compound is important in the field of chemistry. As the field of cannabinoid chemistry grows so does the need for the characterization of new cannabinoids or rare cannabinoids that gain popularity within the consumer and research fields. Hexahydrocannabinol (HHC) a hydrogenated analogue of Δ9-tetrahydrocannabinol (THC), also found in trace amounts naturally within the Cannabis sativa plant, has been gaining attention and popularity within the cannabis industry. Hexahydrocannabidiol (H4CBD) is a synthetic hydrogenated analogue to cannabidiol (CBD). Identifying the diastereomers of the cannabinoids with instrumentation plays a huge role within the chemistry field adding valuable information of the structure and the parameters for others to identify such cannabinoids. Elucidation and characterization of HHC and H4CBD were performed using current analytical techniques such as 1D and 2D nuclear magnetic resonance (NMR), high performance liquid chromatography (HPLC), and gas chromatography-mass spectrometry (GC-MS), effectively characterizing both the diastereomers of HHC and H4CBD.

Xanthine oxidoreductase mediates genotoxic drug-induced autophagy and apoptosis resistance by uric acid accumulation and TGF-β-activated kinase 1 (TAK1) activation

Autophagy is a highly conserved cellular process that profoundly impacts the efficacy of genotoxic chemotherapeutic drugs. TGF-β-activated kinase 1 (TAK1) is a serine/threonine kinase that activates several signaling pathways involved in inducing autophagy and suppressing cell death. Xanthine oxidoreductase (XOR) is a rate-limiting enzyme that converts hypoxanthine to xanthine, and xanthine to uric acid and hydrogen peroxide in the purine catabolism pathway. Recent studies showed that uric acid can bind to TAK1 and prolong its activation. We hypothesized that genotoxic drugs may induce autophagy and apoptosis resistance by activating TAK1 through XOR-generated uric acid. Here, we report that gemcitabine and 5-fluorouracil (5-FU), two genotoxic drugs, induced autophagy in HeLa and HT-29 cells by activating TAK1 and its two downstream kinases, AMP-activated kinase (AMPK) and c-Jun terminal kinase (JNK). XOR knockdown and the XOR inhibitor allopurinol blocked gemcitabine-induced TAK1, JNK, AMPK, and Unc51-like kinase 1 (ULK1)^S555 phosphorylation and gemcitabine-induced autophagy. Inhibition of the ATM-Chk pathway, which inhibits genotoxic drug-induced uric acid production, blocked gemcitabine-induced autophagy by inhibiting TAK1 activation. Exogenous uric acid in its salt form, monosodium urate (MSU), induced autophagy by activating TAK1 and its downstream kinases JNK and AMPK. Gene knockdown or the inhibitors of these kinases blocked gemcitabine- and MSU-induced autophagy. Inhibition of autophagy by allopurinol, chloroquine, and 5Z-7-oxozeaenol (5Z), a TAK1-specific inhibitor, enhanced gemcitabine-induced apoptosis. Our study uncovers a previously unrecognized role of XOR in regulating genotoxic drug-induced autophagy and apoptosis and has implications for designing novel therapeutic strategies for cancer treatment.

Cannabinoids as Prospective Anti-Cancer Drugs: Mechanism of Action in Healthy and Cancer Cells

Endogenous and exogenous cannabinoids modulate many physiological and pathological processes by binding classical cannabinoid receptors 1 (CB1) or 2 (CB2) or non-cannabinoid receptors. Cannabinoids are known to exert antiproliferative, apoptotic, anti-migratory and anti-invasive effect on cancer cells by inducing or inhibiting various signaling cascades. In this chapter, we specifically emphasize the latest research works about the alterations in endocannabinoid system (ECS) components in malignancies and cancer cell proliferation, migration, invasion, angiogenesis, autophagy, and death by cannabinoid administration, emphasizing their mechanism of action, and give a future perspective for clinical use.

Nanotherapeutics in autophagy: a paradigm shift in cancer treatment

Autophagy is a catabolic process in which an organism responds to its nutrient or metabolic emergencies. It involves the degradation of cytoplasmic proteins and organelles by forming double-membrane vesicles called "autophagosomes." They sequester cargoes, leading them to degradation in the lysosomes. Although autophagy acts as a protective mechanism for maintaining homeostasis through cellular recycling, it is ostensibly a cause of certain cancers, but a cure for others. In other words, insufficient autophagy, due to genetic or cellular dysfunctions, can lead to tumorigenesis. However, many autophagy modulators are developed for cancer therapy. Diverse nanoparticles have been documented to induce autophagy. Also, the highly stable nanoparticles show blockage to autophagic flux. In this review, we revealed a general mechanism by which autophagy can be induced or blocked via nanoparticles as well as several studies recently performed to prove the stated fact. In addition, we have also elucidated the paradoxical roles of autophagy in cancer and how their differential role at different stages of various cancers can affect its treatment outcomes. And finally, we summarize the breakthroughs in cancer disease treatments by using metallic, polymeric, and liposomal nanoparticles as potent autophagy modulators.

Use of Cannabis and Cannabinoids for Treatment of Cancer

The endocannabinoid system (ECS) is an ancient homeostasis mechanism operating from embryonic stages to adulthood. It controls the growth and development of many cells and cell lineages. Dysregulation of the components of the ECS may result in uncontrolled proliferation, adhesion, invasion, inhibition of apoptosis and increased vascularization, leading to the development of various malignancies. Cancer is the disease of uncontrolled cell division. In this review, we will discuss whether the changes to the ECS are a cause or a consequence of malignization and whether different tissues react differently to changes in the ECS. We will discuss the potential use of cannabinoids for treatment of cancer, focusing on primary outcome/care-tumor shrinkage and eradication, as well as secondary outcome/palliative care-improvement of life quality, including pain, appetite, sleep, and many more factors. Finally, we will complete this review with the chapter on sex- and gender-specific differences in ECS and response to cannabinoids, and equality of the access to treatments with cannabinoids.

Therapeutic Intervention in Cancer by Isoliquiritigenin from Licorice: A Natural Antioxidant and Redox Regulator

Oxidative stress could lead to a variety of body dysfunctions, including neurodegeneration and cancer, which are closely associated with intracellular signal transducers such as reactive oxygen species (ROS). It has been suggested that ROS is the upstream regulator of autophagy, and that it provides a negative feedback regulation to remove oxidative damage. Defects in the ROS-autophagic redox homeostasis could lead to the increased production of ROS and the accumulation of damaged organelles that in turn promote metabolic reprogramming and induce tumorigenesis. One significant characteristic of pancreatic cancer is the reprogramming of cellular energy metabolism, which facilitates the rapid growth, invasiveness, and the survival of cancer cells. Thus, the rectification of metabolic dysfunction is essential in therapeutic cancer targeting. Isoliquiritigenin (ISL) is a chalcone obtained from the plant Glycyrrhiza glabra, which is a powdered root licorice that has been consumed for centuries in different regions of the world. ISL is known to be a natural antioxidant that possesses diversified functions, including redox regulation in cells. This review contains discussions on the herbal source, biological properties, and anticancer potential of ISL. This is the first time that the anticancer activities of ISL in pancreatic cancer has been elucidated, with a coverage of the involvement of antioxidation, metabolic redox regulation, and autophagy in pancreatic cancer development. Furthermore, some remarks on related compounds of the isoflavonoid biosynthetic pathway of ISL will also be discussed.

A Low Dose of Pure Cannabidiol Is Sufficient to Stimulate the Cytotoxic Function of CIK Cells without Exerting the Downstream Mediators in Pancreatic Cancer Cells

Despite numerous studies conducted over the past decade, the exact role of the cannabinoid system in cancer development remains unclear. Though research has focused on two cannabinoid receptors (CB1, CB2) activated by most cannabinoids, CB2 holds greater attention due to its expression in cells of the immune system. In particular, cytokine-induced killer cells (CIKs), which are pivotal cytotoxic immunological effector cells, express a high-level of CB2 receptors. Herein, we sought to investigate whether inducing CIK cells with cannabidiol can enhance their cytotoxicity and if there are any possible counter effects in its downstream cascade of phosphorylated p38 and CREB using a pancreatic ductal adenocarcinoma cell line (PANC-1). Our results showed that IL-2 modulates primarily the expression of the CB2 receptor on CIK cells used during ex vivo CIK expansion. The autophagosomal-associated scaffold protein p62 was found to co-localize with CB2 receptors in CIK cells and the PANC-1 cell line. CIK cells showed a low level of intracellular phospho-p38 and, when stimulated with cannabidiol (CBD), a donor specific variability in phospho-CREB. CBD significantly decreases the viability of PANC-1 cells presumably by increasing the cytotoxicity of CIK cells. Taken together, in our preclinical in vitro study, we propose that a low effective dose of CBD is sufficient to stimulate the cytotoxic function of CIK without exerting any associated mediator. Thus, the combinatorial approach of non-psychoactive CBD and CIK cells appears to be safe and can be considered for a clinical perspective in pancreatic cancer.

Targeting the Endocannabinoidome in Pancreatic Cancer

Pancreatic Ductal adenocarcinoma (PDAC), the most common malignancy of the pancreas, is an aggressive and lethal form of cancer with a very high mortality rate. High heterogeneity, asymptomatic initial stages and a lack of specific diagnostic markers result in an end-stage diagnosis when the tumour has locally advanced or metastasised. PDAC is resistant to most of the available chemotherapy and radiation therapy treatments, making surgery the most potent curative treatment. The desmoplastic tumour microenvironment contributes to determining PDAC pathophysiology, immune response and therapeutic efficacy. The existing therapeutic approaches such as FDA-approved chemotherapeutics, gemcitabine, abraxane and folfirinox, prolong survival marginally and are accompanied by adverse effects. Several studies suggest the role of cannabinoids as anti-cancer agents. Cannabinoid receptors are known to be expressed in pancreatic cells, with a higher expression reported in pancreatic cancer patients. Therefore, pharmacological targeting of the endocannabinoid system might offer therapeutic benefits in pancreatic cancer. In addition, emerging data suggest that cannabinoids in combination with chemotherapy can increase survival in transgenic pancreatic cancer murine models. This review provides an overview of the regulation of the expanded endocannabinoid system, or endocannabinoidome, in PDAC and will explore the potential of targeting this system for novel anticancer approaches.

Synthesis of Lasalocid-Based Bioconjugates and Evaluation of Their Anticancer Activity

Using rationally designed bioconjugates is an attractive strategy to develop novel anticancer drugs with enhanced therapeutic potential and minimal side effects compared to the native structures. With respect to the promising activity of lasalocid (LAS) toward various cancer cells, this polyether ionophore seems to be an ideal candidate for bioconjugation. Herein, we describe the synthetic access to a cohort of nine conjugated products of LAS, in which the ionophore biomolecule was successfully combined via covalent bonds with selected anticancer therapeutics or other anticancer active components. The in vitro screening of a series of cancer cell lines allowed us to identify three products with improved anticancer activity profiles compared to those of the starting materials. The results indicate that human prostate cancer cells (PC3) and human primary colon cancer cells (SW480) were essentially more sensitive to exposure to LAS derivatives than human keratinocytes (HaCaT). Furthermore, the selected products were stronger inducers of late apoptosis and/or necrosis in PC3 and SW480 cancer cells, when compared to the metastatic variant of colon cancer cells (SW620). To establish the anticancer mechanism of LAS-based bioconjugates, the levels of interleukin 6 (IL-6) and reactive oxygen species (ROS) were measured; the tested compounds significantly reduced the release of IL-6, while the level of ROS was significantly higher in all the cell lines studied.

Perspectives on Challenges in Cannabis Drug Delivery Systems: Where Are We?

Cannabis and its natural derivatives have emerged as promising therapeutics for multiple pathological and nonpathological medical conditions. For example, cannabinoids, the most popular and biologically active chemicals in cannabis, aid in many clinical ailments, including pain, inflammation, epilepsy, sleep disturbances or insomnia, multiple sclerosis, anorexia, schizophrenia, neurodegenerative diseases, anti-nausea, and most importantly, cancer. Despite the comprehensive benefits, certain aspects of cannabis present unique challenges in the medical cannabis landscape. Recent studies have highlighted the inherent challenges associated with cannabinoids' formulation like low solubility, rapid metabolism, poor bioavailability, and erratic pharmacokinetics - all of which contribute to the limited efficacy of cannabinoids. Several efforts are underway to address the bottlenecks and modify the formulations along with the delivery systems to achieve greater solubility/bioavailability, potency, and efficacy in treatment settings while minding the necessary standards for purity associated with the pharmaceutical industry. The current article presents a perspective on (1) a working knowledge of cannabinoids and their mechanisms of action, (2) the landscape of using medicinal cannabis for cancer-related medical conditions along with adversities, (3) current approaches, formulations, and challenges in medicinal cannabis delivery systems (oral, transdermal, pulmonary, and transmucosal), and lastly, (4) emerging approaches to improve delivery systems.

Endocannabinoid System and Tumour Microenvironment: New Intertwined Connections for Anticancer Approaches

The tumour microenvironment (TME) is now recognised as a hallmark of cancer, since tumour:stroma crosstalk supports the key steps of tumour growth and progression. The dynamic co-evolution of the tumour and stromal compartments may alter the surrounding microenvironment, including the composition in metabolites and signalling mediators. A growing number of evidence reports the involvement of the endocannabinoid system (ECS) in cancer. ECS is composed by a complex network of ligands, receptors, and enzymes, which act in synergy and contribute to several physiological but also pathological processes. Several in vitro and in vivo evidence show that ECS deregulation in cancer cells affects proliferation, migration, invasion, apoptosis, and metastatic potential. Although it is still an evolving research, recent experimental evidence also suggests that ECS can modulate the functional behaviour of several components of the TME, above all the immune cells, endothelial cells and stromal components. However, the role of ECS in the tumour:stroma interplay remains unclear and research in this area is particularly intriguing. This review aims to shed light on the latest relevant findings of the tumour response to ECS modulation, encouraging a more in-depth analysis in this field. Novel discoveries could be promising for novel anti-tumour approaches, targeting the microenvironmental components and the supportive tumour:stroma crosstalk, thereby hindering tumour development.

Cannabinoid Cancer Biology and Prevention

Plant-based, synthetic, and endogenous cannabinoids have been shown to control a diverse array of biological processes, including regulation of cell fate across cancers. Their promise as broad-based antitumor agents in preclinical models has led to the initiation of pilot clinical trials. Session 5 of the National Cancer Institute's Cannabis, Cannabinoids and Cancer Research Symposium provides an overview of this research topic. Overall, the presentations highlight cannabinoid signal transduction and specific molecular mechanisms underlying cannabinoid antitumor activity. They also demonstrate the broad-based antitumor activity of the plant-based, synthetic, and endogenous cannabinoid compounds. Importantly, evidence is presented demonstrating when cannabinoids may be contraindicated as a treatment for cancer, as in the case of human papilloma virus-meditated oropharynx cancer or potentially other p38 MAPK pathway-driven cancers. Finally, it is discussed that a key to advancing cannabinoids into the clinic is to conduct well-designed, large-scale clinical trials to determine whether cannabinoids are effective antitumor agents in cancer patients.

Regulation and function of autophagy in pancreatic cancer

Oncogenic KRAS mutation-driven pancreatic ductal adenocarcinoma is currently the fourth-leading cause of cancer-related deaths in the United States. Macroautophagy (hereafter "autophagy") is one of the lysosome-dependent degradation systems that can remove abnormal proteins, damaged organelles, or invading pathogens by activating dynamic membrane structures (e.g., phagophores, autophagosomes, and autolysosomes). Impaired autophagy (including excessive activation and defects) is a pathological feature of human diseases, including pancreatic cancer. However, dysfunctional autophagy has many types and plays a complex role in pancreatic tumor biology, depending on various factors, such as tumor stage, microenvironment, immunometabolic state, and death signals. As a modulator connecting various cellular events, pharmacological targeting of nonselective autophagy may lead to both good and bad therapeutic effects. In contrast, targeting selective autophagy could reduce potential side effects of the drugs used. In this review, we describe the advances and challenges of autophagy in the development and therapy of pancreatic cancer.Abbreviations: AMPK: AMP-activated protein kinase; CQ: chloroquine; csc: cancer stem cells; DAMP: danger/damage-associated molecular pattern; EMT: epithelial-mesenchymal transition; lncRNA: long noncoding RNA; MIR: microRNA; PanIN: pancreatic intraepithelial neoplasia; PDAC: pancreatic ductal adenocarcinoma; PtdIns3K: phosphatidylinositol 3-kinase; SNARE: soluble NSF attachment protein receptor; UPS: ubiquitin-proteasome system.

Oxidative Stress and Multi-Organel Damage Induced by Two Novel Phytocannabinoids, CBDB and CBDP, in Breast Cancer Cells

Over the last few years, much attention has been paid to phytocannabinoids derived from Cannabis for their therapeutic potential. Δ⁹-tetrahydrocannabinol (Δ⁹-THC) and cannabidiol (CBD) are the most abundant compounds of the Cannabis sativa L. plant. Recently, novel phytocannabinoids, such as cannabidibutol (CBDB) and cannabidiphorol (CBDP), have been discovered. These new molecules exhibit the same terpenophenolic core of CBD and differ only for the length of the alkyl side chain. Roles of CBD homologs in physiological and pathological processes are emerging but the exact molecular mechanisms remain to be fully elucidated. Here, we investigated the biological effects of the newly discovered CBDB or CBDP, compared to the well-known natural and synthetic CBD (nat CBD and syn CBD) in human breast carcinoma cells that express CB receptors. In detail, our data demonstrated that the treatment of cells with the novel phytocannabinoids affects cell viability, increases the production of reactive oxygen species (ROS) and activates cellular pathways related to ROS signaling, as already demonstrated for natural CBD. Moreover, we observed that the biological activity is significantly increased upon combining CBD homologs with drugs that inhibit the activity of enzymes involved in the metabolism of endocannabinoids, such as the monoacylglycerol lipase (MAGL) inhibitor, or with drugs that induces the activation of cellular stress pathways, such as the phorbol ester 12-myristate 13-acetate (PMA).

Cannabinoids in the landscape of cancer

INTRODUCTION

Cannabinoids are a group of terpenophenolic compounds derived from the Cannabis sativa L. plant. There is a growing body of evidence from cell culture and animal studies in support of cannabinoids possessing anticancer properties.

METHOD

A database search of peer reviewed articles published in English as full texts between January 1970 and April 2021 in Google Scholar, MEDLINE, PubMed and Web of Science was undertaken. References of relevant literature were searched to identify additional studies to construct a narrative literature review of oncological effects of cannabinoids in pre-clinical and clinical studies in various cancer types.

RESULTS

Phyto-, endogenous and synthetic cannabinoids demonstrated antitumour effects both in vitro and in vivo. However, these effects are dependent on cancer type, the concentration and preparation of the cannabinoid and the abundance of receptor targets. The mechanism of action of synthetic cannabinoids, (-)-trans-Δ9-tetrahydrocannabinol (Δ9-THC) and cannabidiol (CBD) has mainly been described via the traditional cannabinoid receptors; CB1 and CB2, but reports have also indicated evidence of activity through GPR55, TRPM8 and other ion channels including TRPA1, TRPV1 and TRPV2.

CONCLUSION

Cannabinoids have shown to be efficacious both as a single agent and in combination with antineoplastic drugs. These effects have occurred through various receptors and ligands and modulation of signalling pathways involved in hallmarks of cancer pathology. There is a need for further studies to characterise its mode of action at the molecular level and to delineate efficacious dosage and route of administration in addition to synergistic regimes.

Systematic Review of the Integrative Medicine Recommendations for Patients with Pancreatic Cancer

Introduction: Integrative medicine (IM) is a relatively new field where non-traditional therapies with peer-reviewed evidence are incorporated or integrated with more traditional approaches. Methods: A systematic review of the literature from the last 10 years was done by searching clinical trials and randomized-controlled trials on Pubmed that discuss nutrition, supplementation, and lifestyle changes associated with “Pancreatic Cancer.” Results: Only 50 articles ultimately met the inclusion criteria for this review. A total of 15 articles discussed the role of obesity and 10 discussed the influence of stress in increasing the risk of pancreatic cancer. Six discussed the potential beneficial role of Vitamins, 5 of cannabinoids, 4 an anti-inflammatory diet, 3 of nut consumption, 2 of green tea consumption, 2 of curcumin supplementation, 1 role of melatonin, and 1 of probiotics. One article each was found on the theoretical benefits of adhering to either a Mediterranean or ketogenic diet. Discussion: As more surgeons become interested in IM, it is hoped that more diseases where the curative treatment is mainly surgical can benefit from the all-encompassing principles of IM in an effort to improve quality of life and survival in patients with pancreatic cancer.

The Interplay between the Immune and the Endocannabinoid Systems in Cancer

The therapeutic potential of Cannabis sativa has been recognized since ancient times. Phytocannabinoids, endocannabinoids and synthetic cannabinoids activate two major G protein-coupled receptors, subtype 1 and 2 (CB1 and CB2). Cannabinoids (CBs) modulate several aspects of cancer cells, such as apoptosis, autophagy, proliferation, migration, epithelial-to-mesenchymal transition and stemness. Moreover, agonists of CB1 and CB2 receptors inhibit angiogenesis and lymphangiogenesis in vitro and in vivo. Low-grade inflammation is a hallmark of cancer in the tumor microenvironment (TME), which contains a plethora of innate and adaptive immune cells. These cells play a central role in tumor initiation and growth and the formation of metastasis. CB2 and, to a lesser extent, CB1 receptors are expressed on a variety of immune cells present in TME (e.g., T cells, macrophages, mast cells, neutrophils, NK cells, dendritic cells, monocytes, eosinophils). The activation of CB receptors modulates a variety of biological effects on cells of the adaptive and innate immune system. The expression of CB2 and CB1 on different subsets of immune cells in TME and hence in tumor development is incompletely characterized. The recent characterization of the human cannabinoid receptor CB2-G_i signaling complex will likely aid to design potent and specific CB2/CB1 ligands with therapeutic potential in cancer.

Scoping Review and Meta-Analysis Suggests that Cannabis Use May Reduce Cancer Risk in the United States

Introduction: Cannabis smoke contains carcinogens similar to tobacco, in addition to compounds with antitumor activity. Cannabis use reduces the risk of obesity and cannabinoids inhibit chronic inflammation, known causes of cancer. The net effect of Cannabis use on cancer risk is not known. Objective: To examine the association between Cannabis use and cancer risk in the United States. Methods: Identify and analyze published data on cancer risk in Cannabis users. Results: A total of 55 data points, consisting of risk ratios of cancer in Cannabis users and nonusers, were identified from 34 studies. Of these, 5 did not contain data essential for inclusion in the meta-analysis. The remaining data showed a nonsignificant trend to an association with reduced risk (relative risk [RR]=0.90, p>0.06, N=50) although heterogeneity is high (I²=72.4%). Removal of data with high risk of selection bias (defined as those from North Africa and those that failed to adjust for tobacco) and data with high risk of performance bias (defined as those with fewer than 20 cases or controls among Cannabis users) resulted in an RR <1.0 (RR=0.86, p<0.017, N=24) and large effect size (Hedges g=0.66), but did not decrease heterogeneity (I²=74.9). Of all cancer sites, only testicular cancer showed an RR value >1, although this was not significant and had a negligible effect size (RR=1.12, p=0.3, Hedges g=0.02). Following removal of testicular cancers the remaining data showed a decrease in risk (RR=0.87, p<0.025, N=41). Cancers of the head and neck showed a negative association with cancer risk (RR=0.83, p<0.05), with a large effect size (Hedges g=0.55), but high heterogeneity (I²=79.2%). RR did not reach statistical significance in the remaining cancer site categories (lung, testicular, obesity-associated, other). The data are consistent with a negative association between Cannabis use and nontesticular cancer, but there is low confidence in this result due to high heterogeneity and a paucity of data for many cancer types.

SMAD4 loss is associated with response to neoadjuvant chemotherapy plus hydroxychloroquine in patients with pancreatic adenocarcinoma

SMAD4, a tumor suppressor gene, is lost in up to 60%–90% of pancreatic adenocarcinomas (PDAs). Loss of SMAD4 allows tumor progression by upregulating autophagy, a cell survival mechanism that counteracts apoptosis and allows intracellular recycling of macromolecules. Hydroxychloroquine (HCQ) is an autophagy inhibitor. We studied whether HCQ treatment in SMAD4 deficient PDA may prevent therapeutic resistance induced by autophagy upregulation. We retrospectively analyzed the SMAD4 status of patients with PDA enrolled in two prospective clinical trials evaluating pre‐operative HCQ. The first dose escalation trial demonstrated the safety of preoperative gemcitabine with HCQ (NCT01128296). More recently, a randomized trial of gemcitabine/nab‐paclitaxel +/− HCQ evaluated Evans Grade histopathologic response (NCT01978184). The effect of SMAD4 loss on response to HCQ and chemotherapy was studied for association with clinical outcome. Fisher’s exact test and log‐rank test were used to assess response and survival. Fifty‐two patients receiving HCQ with neoadjuvant chemotherapy were studied. Twenty‐five patients had SMAD4 loss (48%). 76% of HCQ‐treated patients with SMAD4 loss obtained a histopathologic response greater than or equal to 2A, compared with only 37% with SMAD4 intact (p = 0.006). Although loss of SMAD4 has been associated with worse outcomes, in the current study, loss of SMAD4 was not associated with a detriment in median overall survival in HCQ‐treated patients (34.43 months in SMAD4 loss vs. 27.27 months in SMAD4 intact, p = 0.18). The addition of HCQ to neoadjuvant chemotherapy in patients with PDA may improve treatment response in those with SMAD4 loss. Further study of the relationship among SMAD4, autophagy, and treatment outcomes in PDA is warranted.

Kaempferol induces ROS-dependent apoptosis in pancreatic cancer cells via TGM2-mediated Akt/mTOR signaling

BACKGROUND

Kaempferol, a natural flavonoid, exhibits anticancer properties by scavenging reactive oxygen species (ROS). However, increasing evidence has demonstrated that, under certain conditions, kaempferol can inhibit tumor growth by upregulating ROS levels. In this study, we aimed to investigate whether kaempferol effectively suppresses pancreatic cancer through upregulation of ROS, and to explore the underlying molecular mechanism.

METHODS

PANC-1 and Mia PaCa-2 cells were exposed to different concentrations of kaempferol. Cell proliferation and colony formation were evaluated by CCK-8 and colony formation assays. Flow cytometry was performed to assess the ROS levels and cell apoptosis. The mRNA sequencing and KEGG enrichment analysis were performed to identify differentially expressed genes and to reveal significantly enriched signaling pathways in response to kaempferol treatment. Based on biological analysis, we hypothesized that tissue transglutaminase (TGM2) gene was an essential target for kaempferol to induce ROS-related apoptosis in pancreatic cancer. TGM2 was overexpressed by lentivirus vector to verify the effect of TGM2 on the ROS-associated apoptotic signaling pathway. Western blot and qRT-PCR were used to determine the protein and mRNA levels, respectively. The prognostic value of TGM2 was analyzed by Gene Expression Profiling Interactive Analysis (GEPIA) tools based on public data from the TCGA database.

RESULTS

Kaempferol effectively suppressed pancreatic cancer in vitro and in vivo. Kaempferol promoted apoptosis in vitro by increasing ROS generation, which was involved in Akt/mTOR signaling. TGM2 levels were significantly increased in PDAC tissues compared with normal tissues, and high TGM2 expression was positively correlated with poor prognosis in pancreatic cancer patients. Decreased TGM2 mRNA and protein levels were observed in the cells after treatment with kaempferol. Additionally, TGM2 overexpression downregulated ROS production and inhibited the abovementioned apoptotic signaling pathway.

CONCLUSIONS

Kaempferol induces ROS-dependent apoptosis in pancreatic cancer cells via TGM2-mediated Akt/mTOR signaling, and TGM2 may represent a promising prognostic biomarker for pancreatic cancer.

Molecular Mechanism of Cannabinoids in Cancer Progression

Cannabinoids are a family of heterogeneous compounds that mostly interact with receptors eliciting several physiological effects both in the central and peripheral nervous systems and in peripheral organs. They exert anticancer action by modulating signaling pathways involved in cancer progression; furthermore, the effects induced by their use depend on both the type of tumor and their action on the components of the endocannabinoid system. This review will explore the mechanism of action of the cannabinoids in signaling pathways involved in cancer proliferation, neovascularisation, migration, invasion, metastasis, and tumor angiogenesis.

Cannabidiol induces autophagy via ERK1/2 activation in neural cells

Autophagy is a lysosomal catabolic process essential to cell homeostasis and is related to the neuroprotection of the central nervous system. Cannabidiol (CBD) is a non-psychotropic phytocannabinoid present in Cannabis sativa. Many therapeutic actions have been linked to this compound, including autophagy activation. However, the precise underlying molecular mechanisms remain unclear, and the downstream functional significance of these actions has yet to be determined. Here, we investigated CBD-evoked effects on autophagy in human neuroblastoma SH-SY5Y and murine astrocyte cell lines. We found that CBD-induced autophagy was substantially reduced in the presence of CB1, CB2 and TRPV1 receptor antagonists, AM 251, AM 630 and capsazepine, respectively. This result strongly indicates that the activation of these receptors mediates the autophagic flux. Additionally, we demonstrated that CBD activates autophagy through ERK1/2 activation and AKT suppression. Interestingly, CBD-mediated autophagy activation is dependent on the autophagy initiator ULK1, but mTORC1 independent. Thus, it is plausible that a non-canonical pathway is involved. Our findings collectively provide evidence that CBD stimulates autophagy signal transduction via crosstalk between the ERK1/2 and AKT kinases, which represent putative regulators of cell proliferation and survival. Furthermore, our study sheds light on potential therapeutic cannabinoid targets that could be developed for treating neurodegenerative disorders.

Cannabis sativa: Interdisciplinary Strategies and Avenues for Medical and Commercial Progression Outside of CBD and THC

Cannabis sativa (Cannabis) is one of the world’s most well-known, yet maligned plant species. However, significant recent research is starting to unveil the potential of Cannabis to produce secondary compounds that may offer a suite of medical benefits, elevating this unique plant species from its illicit narcotic status into a genuine biopharmaceutical. This review summarises the lengthy history of Cannabis and details the molecular pathways that underpin the production of key secondary metabolites that may confer medical efficacy. We also provide an up-to-date summary of the molecular targets and potential of the relatively unknown minor compounds offered by the Cannabis plant. Furthermore, we detail the recent advances in plant science, as well as synthetic biology, and the pharmacology surrounding Cannabis. Given the relative infancy of Cannabis research, we go on to highlight the parallels to previous research conducted in another medically relevant and versatile plant, Papaver somniferum (opium poppy), as an indicator of the possible future direction of Cannabis plant biology. Overall, this review highlights the future directions of cannabis research outside of the medical biology aspects of its well-characterised constituents and explores additional avenues for the potential improvement of the medical potential of the Cannabis plant.

The Role of Reactive Oxygen Species in Tumor Treatment and its Impact on Bone Marrow Hematopoiesis

Reactive oxygen species (ROS), an important molecule inducing oxidative stress in organisms, play a key role in tumorigenesis, tumor progression and recurrence. Recent findings on ROS have shown that ROS can be used to treat cancer as they accelerate the death of tumor cells. At present, pro-oxidant drugs that are intended to increase ROS levels of the tumor cells have been widely used in the clinic. However, ROS are a double-edged sword in the treatment of tumors. High levels of ROS induce not only the death of tumor cells but also oxidative damage to normal cells, especially bone marrow hemopoietic cells, which leads to bone marrow suppression and (or) other side effects, weak efficacy of tumor treatment and even threatening patients' life. How to enhance the killing effect of ROS on tumor cells while avoiding oxidative damage to the normal cells has become an urgent issue. This study is a review of the latest progress in the role of ROS-mediated programmed death in tumor treatment and prevention and treatment of oxidative damage in bone marrow induced by ROS.

ATDC binds to KEAP1 to drive NRF2-mediated tumorigenesis and chemoresistance in pancreatic cancer

Pancreatic ductal adenocarcinoma is a lethal disease characterized by late diagnosis, propensity for early metastasis and resistance to chemotherapy. Little is known about the mechanisms that drive innate therapeutic resistance in pancreatic cancer. The ataxia-telangiectasia group D-associated gene (ATDC) is overexpressed in pancreatic cancer and promotes tumor growth and metastasis. Our study reveals that increased ATDC levels protect cancer cells from reactive oxygen species (ROS) via stabilization of nuclear factor erythroid 2-related factor 2 (NRF2). Mechanistically, ATDC binds to Kelch-like ECH-associated protein 1 (KEAP1), the principal regulator of NRF2 degradation, and thereby prevents degradation of NRF2 resulting in activation of a NRF2-dependent transcriptional program, reduced intracellular ROS and enhanced chemoresistance. Our findings define a novel role of ATDC in regulating redox balance and chemotherapeutic resistance by modulating NRF2 activity.

Protopine/Gemcitabine Combination Induces Cytotoxic or Cytoprotective Effects in Cell Type-Specific and Dose-Dependent Manner on Human Cancer and Normal Cells

The natural alkaloid protopine (PRO) exhibits pharmacological properties including anticancer activity. We investigated the effects of PRO, alone and in combination with the chemotherapeutic gemcitabine (GEM), on human tumor cell lines and non-tumor human dermal fibroblasts (HDFs). We found that treatments with different PRO/GEM combinations were cytotoxic or cytoprotective, depending on concentration and cell type. PRO/GEM decreased viability in pancreatic cancer MIA PaCa-2 and PANC-1 cells, while it rescued the GEM-induced viability decline in HDFs and in tumor MCF-7 cells. Moreover, PRO/GEM decreased G1, S and G2/M phases, concomitantly with an increase of subG1 phase in MIA PaCa-2 and PANC-1 cells. Differently, PRO/GEM restored the normal progression of the cell cycle, altered by GEM, and decreased cell death in HDFs. PRO alone increased mitochondrial reactive oxygen species (ROS) in MIA PaCa-2, PANC-1 cells and HDFs, while PRO/GEM increased both intracellular and mitochondrial ROS in the three cell lines. These results indicate that specific combinations of PRO/GEM may be used to induce cytotoxic effects in pancreatic tumor MIA PaCa-2 and PANC-1 cells, but have cytoprotective or no effects in HDFs.

Synthetic Cannabinoids Induce Autophagy and Mitochondrial Apoptotic Pathways in Human Glioblastoma Cells Independently of Deficiency in TP53 or PTEN Tumor Suppressors

Simple Summary

Glioblastomas (GBMs) are aggressive brain tumors with frequent genetic defects in TP53 and PTEN tumor suppressor genes, which render tumors refractory to standard chemotherapeutics. Natural and synthetic cannabinoids showed antitumor activity in glioma cells and animal glioma models. Due to differences in the expression of cannabinoid type 2 receptors (CB2), which are abundant in GBMs but absent from a healthy brain, we tested synthetic cannabinoids for their ability to kill numerous glioma cells. We performed multiple biochemical analyses to determine which cell death pathways are activated in human glioma cells. We demonstrate high susceptibility of human glioblastoma cells to synthetic cannabinoids, despite genetic defects contributing to apoptosis resistance, which makes cannabinoids promising anti-glioma therapeutics.

Abstract

Glioblastomas (GBMs) are aggressive brain tumors with frequent genetic alterations in TP53 and PTEN tumor suppressor genes rendering resistance to standard chemotherapeutics. Cannabinoid type 1 and 2 (CB1/CB2) receptor expression in GBMs and antitumor activity of cannabinoids in glioma cells and animal models, raised promises for a targeted treatment of these tumors. The susceptibility of human glioma cells to CB2-agonists and their mechanism of action are not fully elucidated. We determined CB1 and CB2 expression in 14 low-grade and 21 high-grade tumor biopsies, GBM-derived primary cultures and established cell lines. The non-selective CB receptor agonist WIN55,212-2 (but not its inactive enantiomer) or the CB2-selective agonist JWH133 induced apoptosis in patient-derived glioma cultures and five established glioma cell lines despite p53 and/or PTEN deficiency. Growth inhibitory efficacy of cannabinoids correlated with CB1/CB2 expression (EC₅₀ WIN55,212-2: 7.36–15.70 µM, JWH133: 12.15–143.20 µM). Treatment with WIN55,212-2 or JWH133 led to activation of the apoptotic mitochondrial pathway and DNA fragmentation. Synthetic cannabinoid action was associated with the induction of autophagy and knockdown of autophagy genes augmented cannabinoid-induced apoptotic cell death. The high susceptibility of human glioblastoma cells to synthetic cannabinoids, despite genetic defects contributing to apoptosis resistance, makes cannabinoids promising anti-glioma therapeutics.

Medical Cannabis in Oncology: a Valuable Unappreciated Remedy or an Undesirable Risk?

OPINION STATEMENT

The use of the cannabis plant by cancer patients has been rising significantly in the past few years worldwide, primarily driven by public demand. There is an obvious need for more reliable scientific data, pharmacology information, a better understanding of its mode of action, and available clinical evidence supporting its robust use. Physicians must complete a thorough medical assessment, screening for potential drugs, or treatment contraindications before allowing its consumption. In light of the growing popularity of cannabis usage, it is highly essential that, in the near future, the medical community will be able to provide practical recommendations and explicit guidelines, including doses, and that cannabinoid concentrations in the used products are defined regarding its prescription before any medical procedure involving its usage is authorized. Here, we review and describe the favorable outcomes demonstrating the benefits of cannabis as an adjunctive treatment to conventional medicines for chemotherapy-induced nausea, vomiting, and cancer-related pain (primarily refractory chronic or neuropathic pain). Although not yet substantial enough, the treatment of anorexia, insomnia, depression, and anxiety is also seemingly favorable. To date, reports regarding its anti-neoplastic effects or its potent immunosuppressive properties influencing response to immunotherapy are still very conflicting and controversial. Thus, with the current state of evidence, cannabis use is not advisable as initial treatment, as an adjunct or an advanced line of care. In the coming years, we expect that preclinical data and animal models will shift to the clinical arena, and more patients will be recruited for clinical trials, and their reports will advance the field. Thus, physicians should prescribe cannabis only if careful clarification and consideration is provided together with a follow-up response evaluation.

ACPA decreases non-small cell lung cancer line growth through Akt/PI3K and JNK pathways in vitro

Therapeutic agents used for non-small cell lung cancer (NSCLC) have limited curative efficacy and may trigger serious adverse effects. Cannabinoid ligands exert antiproliferative effect and induce apoptosis on numerous epithelial cancers. We confirmed that CB1 receptor (CB1R) is expressed in NSCLC cells in this study. Arachidonoylcyclopropylamide (ACPA) as a synthetic, CB1R-specific ligand decreased proliferation rate in NSCLC cells by WST-1 analysis and real-time proliferation assay (RTCA). The half-maximal inhibitory concentration (IC50) dose of ACPA was calculated as 1.39 × 10-12 M. CB1 antagonist AM281 inhibited the antiproliferative effect of ACPA. Flow cytometry and ultrastructural analyzes revealed significant early and late apoptosis with diminished cell viability. Nano-immunoassay and metabolomics data on activation status of CB1R-mediated pro-apoptotic pathways found that ACPA inhibited Akt/PI3K pathway, glycolysis, TCA cycle, amino acid biosynthesis, and urea cycle and activated JNK pathway. ACPA lost its chemical stability after 24 hours tested by liquid chromatography-mass spectrometry (LC-MS/MS) assay. A novel ACPA-PCL nanoparticle system was developed by nanoprecipitation method and characterized. Sustained release of ACPA-PCL nanoparticles also reduced proliferation of NSCLC cells. Our results demonstrated that low dose ACPA and ACPA-PCL nanoparticle system harbor opportunities to be developed as a novel therapy in NSCLC patients that require further in vivo studies beforehand to validate its anticancer effect.

Therapeutic potential of cannabinoids in combination cancer therapy

Derivatives of the plant Cannabis sativa have been used for centuries for both medical and recreational purposes, as well as industrial. The first proof of its medicinal use comes from ancient China, although there is evidence of its earlier utilization in Europe and Asia. In the 19th century, European practitioners started to employ cannabis extracts to treat tetanus, convulsions, and mental diseases and, in 1851, cannabis made its appearance in the Pharmacopoeia of the United States as an analgesic, hypnotic and anticonvulsant. It was only in 1937 that the Marijuana Tax Act prohibited the use of this drug in the USA. The general term Cannabis is commonly used by the scientific and scholar community to indicate derivatives of the plant Cannabis sativa. The word cannabinoid is a term describing chemical compounds that are either derivate of Cannabis (phytocannabinoids) or artificial analogues (synthetic) or are produced endogenously by the body (endocannabinoids). A more casual term "marijuana" or "weed", a compound derived from dried Cannabis flower tops and leaves, has progressively superseded the term cannabis when referred to its recreational use. The 2018 World health organisation (WHO) data suggest that nearly 2.5% of the global population (147 million) uses marijuana and some countries, such as Canada and Uruguay, have already legalised it. Due to its controversial history, the medicinal use of cannabinoids has always been a centre of debate. The isolation and characterisation of Δ⁹ tetrahydrocannabinol (THC), the major psychoactive component of cannabis and the detection of two human cannabinoid receptor (CBRs) molecules renewed interest in the medical use of cannabinoids, boosting research and commercial heed in this sector. Some cannabinoid-based drugs have been approved as medications, mainly as antiemetic, antianorexic, anti-seizure remedies and in cancer and multiple sclerosis patients' palliative care. Nevertheless, due to the stigma commonly associated with these compounds, cannabinoids' potential in the treatment of conditions such as cancer is still largely unknown and therefore underestimated.

Cannabinoids in Medicine: Cancer, Immunity, and Microbial Diseases

Recently, there has been a growing interest in the medical applications of Cannabis plants. They owe their unique properties to a group of secondary metabolites known as phytocannabinoids, which are specific for this genus. Phytocannabinoids, and cannabinoids generally, can interact with cannabinoid receptors being part of the endocannabinoid system present in animals. Over the years a growing body of scientific evidence has been gathered, suggesting that these compounds have therapeutic potential. In this article, we review the classification of cannabinoids, the molecular mechanisms of their interaction with animal cells as well as their potential application in the treatment of human diseases. Specifically, we focus on the research concerning the anticancer potential of cannabinoids in preclinical studies, their possible use in cancer treatment and palliative medicine, as well as their influence on the immune system. We also discuss their potential as therapeutic agents in infectious, autoimmune, and gastrointestinal inflammatory diseases. We postulate that the currently ongoing and future clinical trials should be accompanied by research focused on the cellular and molecular response to cannabinoids and Cannabis extracts, which will ultimately allow us to fully understand the mechanism, potency, and safety profile of cannabinoids as single agents and as complementary drugs.

Novel Liver X Receptor Ligand GAC0001E5 Disrupts Glutamine Metabolism and Induces Oxidative Stress in Pancreatic Cancer Cells

Pancreatic ductal adenocarcinoma (PDAC) is the predominant form of pancreatic cancer with a high mortality rate due to the lack of early detection and effective treatment options for advanced diseases. Metabolic reprogramming, a common hallmark of malignant transformation in pancreatic cancer, is critical for the growth and survival of cancer cells and a potential target mechanism for the treatment of pancreatic cancer. PDAC cells have upregulated glutamine metabolism to meet their biosynthetic and oxidative demands. Liver X receptors (LXRs) are ligand-dependent transcription factors involved in maintaining metabolic homeostasis. LXRs regulate critical cancer-related processes and pathways, including cholesterol, glucose and lipid metabolism, and inflammatory and immune responses. Analysis of transcriptomic data from PDAC clinical samples reveals overexpression of LXRs and their target genes in tumors as compared to normal tissue controls. Targeting LXRs with the novel LXR inverse agonist and degrader GAC0001E5 inhibited PDAC cell proliferation. Using a metabolomics approach, we discovered that 1E5 inhibits glutamine anaplerosis and induces oxidative stress, which are detrimental to PDAC cells. These findings highlight a novel role for LXR in regulating cancer metabolism and the potential application of LXR modulators in targeting cancer metabolism in pancreatic cancer and other malignancies.

New derivatives of 4'-phenyl-2,2':6',2″-terpyridine as promising anticancer agents

Terpyridine derivatives are known from their broad application including anticancer properties. In this work we present the newly synthesized 4'-phenyl-2,2':6',2″-terpyridine group with high antiproliferative activity. We suggest that these compounds influence cellular redox homeostasis. Cancer cells are particularly susceptible to any changes in the redox balance because of their handicapped and inefficient antioxidant cellular systems. The antiproliferative activity of the studied compounds was tested on five different cell lines that represent several types of tumours; glioblastoma, leukemia, breast, pancreatic and colon. Additionally, we also tested their selectivity towards normal cells. We performed molecular biology studies in order to detect the response of a cell to its treatment with the compounds that were tested. We looked at the in-depth changes in the proteins and cellular pathways that lead to cell cycle inhibition (G0/G1 and S), and consequently, death on the apoptosis and autophagy pathways. We proved that the studied compounds targeted DNA as well. Special attention was paid to the targets connected with ROS generation.