Benzophenones from Betula alnoides with Antiausterity Activities against the PANC-1 Human Pancreatic Cancer Cell Line

Piper longum Constituents Induce PANC-1 Human Pancreatic Cancer Cell Death under Nutrition Starvation

Pancreatic cancer is a highly aggressive form of cancer with a poor prognosis, partly due to 'austerity', a phenomenon of tolerance to nutrient deprivation and survival in its hypovascular tumor microenvironment. Anti-austerity agents which preferentially diminish the survival of cancer cells under nutrition starvation is regarded as new generation anti-cancer agents. This study investigated the potential of Piper longum constituents as anti-austerity agents. The ethanolic extract of Piper longum was found to have preferential cytotoxicity towards PANC-1 human pancreatic cancer cells in a nutrient-deprived medium (NDM). Further investigation led to the identification of pipernonaline (3) as the lead compound with the strongest anti-austerity activity, inducing cell death and inhibiting migration in a normal nutrient medium, as well as strongly inhibiting the Akt/mTOR/autophagy pathway. Therefore, pipernonaline (3) holds promise as a novel antiausterity agent for the treatment of pancreatic cancer.

Nicolaioidesin C: An Antiausterity Agent Shows Promising Antitumor Activity in a Pancreatic Cancer Xenograft Mouse Model

Human pancreatic tumors are hypovascular in nature, and their tumor microenvironment is often characterized by hypoxia and severe nutrient deprivation due to uncontrolled heterogeneous growth, a phenomenon known as "austerity". However, pancreatic tumor cells have the inherent ability to adapt and thrive even in such low nutrient and hypoxic microenvironments. Anticancer drugs such as gemcitabine and paclitaxel, which target rapidly proliferating cells, are often ineffective against nutrient-deprived pancreatic cancer cells. In order to overcome this limitation, the search for novel agents that can eliminate cancer cells' adaptations to nutrition starvation, also known as "antiausterity" agents, represents a promising strategy to make the cancer cells susceptible to treatment. The natural product (+)-nicolaioidesin C (Nic-C) was found to have potent antiausterity activity against the PANC-1 human pancreatic cancer cell line in a nutrient-deprived condition. However, its efficacy in vivo remained untested. To address this, we synthesized Nic-C in its racemic form and evaluated its antitumor potential in a human pancreatic cancer xenograft model. Nic-C inhibited pancreatic cancer cell migration and colony formation and significantly inhibited tumor growth in MIA PaCa-2 xenografts in a dose-dependent manner. Furthermore, Nic-C inhibited the Akt/mTOR and autophagy signaling pathways in both in vitro and in vivo studies. Metabolomic profiling of in vivo tumor samples suggests that Nic-C downregulates amino acid metabolism while upregulating sphingolipid metabolism.

Targeting Pancreatic Cancer with Novel Plumbagin Derivatives: Design, Synthesis, Molecular Mechanism, In Vitro and In Vivo Evaluation

Pancreatic tumors grow in an "austerity" tumor microenvironment characterized by nutrient deprivation and hypoxia. This leads to the activation of adaptive pathways in pancreatic cancer cells, promoting tolerance to nutrition starvation and aggressive malignancy. Conventional anticancer drugs are often ineffective against tumors that grow in such austerity condition. Plumbagin, a plant-derived naphthoquinone, has shown potent preferential cytotoxicity against pancreatic cancer cells under nutrient-deprived conditions. Therefore, we synthesized a series of plumbagin derivatives and found that 2-(cyclohexylmethyl)-plumbagin (3f) was the most promising compound with a PC₅₀ value of 0.11 μM. Mechanistically, 3f was found to inhibit the PI3K/Akt/mTOR signaling pathways, leading to cancer cell death under nutrient-deprived conditions. In vivo studies using pancreatic cancer xenograft mouse models confirmed the efficacy of 3f, demonstrating significant inhibition of tumor growth in a dose-dependent manner. Compound 3f represents a highly promising lead for anticancer drug development based on an antiausterity strategy.

Schomburginones A‒J, geranylated benzophenones from the leaves of Garcinia schomburgkiana and their cytotoxic and anti-inflammatory activities

Ten undescribed benzophenones, schomburginones A-J, together with 14 known analogs were isolated from the leaves of Garcinia schomburgkiana, an edible plant native to the Indochina region. The structures of the undescribed compounds were elucidated by NMR combined with HRMS spectroscopy, while their absolute configurations were determined using ECD and single-crystal X-ray diffraction analysis. The isolated metabolites represent benzophenone derivatives containing a modified monoterpene unit, including tri- and tetracyclic skeletons, which are rarely found in genus Garcinia. The cytotoxic evaluation on three cancerous cell lines demonstrated that schomburginone G, schomburginone H, and 3-geranyl-2,4,6-trihydroxybenzophenone were active against HeLa cells with IC₅₀ values in the range of 12.2-15.7 μM, respectively, and selective compared to the non-cancerous L929 cells (SI > 3.5). In addition, the three cytotoxic compounds together with clusiacyclol A showed significant NO inhibitory activity in RAW 264.7 macrophage cells over 85% inhibition without obvious cytotoxicity at a final concentration of 100 μM. The promising activities of these compounds in cytotoxic and anti-inflammatory assays make them attractive for further study in the development of anticancer drugs.

Ugi Adducts as Novel Anti-austerity Agents against PANC-1 Human Pancreatic Cancer Cell Line: A Rapid Synthetic Approach

Pancreatic cancer cells have an inherent tolerance to withstand nutrition starvation, allowing them to survive in hypovascular tumor microenvironments that lack of sufficient nutrients and oxygen. Developing anti-cancer agents that target this tolerance to nutritional starvation is a promising anti-austerity strategy for eradicating pancreatic cancer cells in their microenvironment. In this study, we employed a chemical biology approach using the Ugi reaction to rapidly synthesize new anti-austerity agents and evaluate their structure-activity relationships. Out of seventeen Ugi adducts tested, Ugi adduct 11 exhibited the strongest anti-austerity activity, showing preferential cytotoxicity against PANC-1 pancreatic cancer cells with a PC50 value of 0.5 µM. Further biological investigation of Ugi adduct 11 revealed a dramatic alteration of cellular morphology, leading to PANC-1 cell death within 24 h under nutrient-deprived conditions. Furthermore, the R absolute configuration of 11 was found to significantly contribute to the preferential anti-austerity ability toward PANC-1, with a PC50 value of 0.2 µM. Mechanistically, Ugi adduct (R)-11 was found to inhibit the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway preferentially under nutrition starvation conditions. Consequently, Ugi-adduct (R)-11 could be a promising candidate for drug development targeting pancreatic cancer based on the anti-austerity strategy. Our study also demonstrated that the Ugi reaction-based chemical engineering of natural product extracts can be used as a rapid method for discovering novel anti-austerity agents for combating pancreatic cancer.

Chemical Constituents of Callistemon subulatus and Their Anti-Pancreatic Cancer Activity against Human PANC-1 Cell Line

An n-hexane extract of Callistemon subulatus was found to exhibit potent cytotoxicity against PANC-1 human pancreatic cancer cells, preferentially under nutrition starvation conditions, with a PC₅₀ value of 6.2 µg/mL. Phytochemical investigation of this bioactive extract resulted in the isolation of fifteen compounds (1–15), including a new compound, subulatone A (–). The structure of compound 1 was elucidated using HRFABMS and NMR spectroscopic analyses. The isolated compounds were tested for their preferential cytotoxicity against the PANC-1 human pancreatic cancer cell line, using an anti-austerity strategy. Among these, myrtucommulone A (2) showed highly potent preferential cytotoxicity, with a PC₅₀ value of 0.28 µM. Myrtucommulone A (2) was found to alter PANC-1 cell morphology, inhibit cell migration, and downregulate the PI3K/Akt/mTOR and autophagy signaling pathways in nutrient-deprived media, leading to cancer cell death. Therefore, myrtucommulone A (2) is a lead compound for anticancer drug development based on an anti-austerity strategy.

Terpenoids from Nardostachys jatamansi and their cytotoxic activity against human pancreatic cancer cell lines

Five previously unreported terpenoids, together with fifteen known analogs, were isolated from a methanol extract of the roots and rhizomes of Nardostachys jatamansi. Their structures, including absolute configurations, were elucidated by spectroscopic data and electronic circular dichroism (ECD) spectra analyses, as well as single-crystal X-ray diffraction for crystalline compounds. Structurally, (4R,5S,6S,7R)-1(10)-aristolane-8,9-diacid is a novel 8,9-dicarboxylic acid derivative of aristolane-type sesquiterpenoid. (4R,6S,7R,10S)-10-Hydroxyguaia-1(5)-6,7-epoxy-2-one is an undescribed analogue of nardoguaianone K, with a rare 6,7-epoxide group. (4R,5R,6R,8R)-1(10)-Isonardosinone-8-ol-9-one-7,11-lactone is an isonardosinane-type sesquiterpene bearing a γ-lactone ring. Dinardokanshone F is a rare example of a sesquiterpene dimer from N. jatamansi connected by an oxo bridge. The isolates were evaluated for their cytotoxic activity against four human pancreatic cancer cell lines (CFPAC-1, PANC-1, CAPAN-2 and SW1990). Compound epoxynardosinone exhibited significant cytotoxicity against CAPAN-2 cell lines with IC₅₀ value of 2.60 ± 1.85 μM. 1-Hydroxylaristolone displayed comparable cytotoxicity on CFPAC-1 cell lines (IC₅₀ 1.12 ± 1.19 μM), compared to Taxol (IC₅₀ 0.32 ± 0.13 μM). 1-Hydroxylaristolone, 1(10)-aristolane-9β-ol, 1(10)-aristolen-2-one, alpinenone, valtrate isovaleroyloxyhydrine and nardostachin displayed stronger cytotoxicity against PANC-1 cell lines with IC₅₀ values ranging from 0.01 ± 0.01 to 6.50 ± 1.10 μM. 1(10)-Aristolane-9β-ol, 10-hydroxyguaia-1(5)-6,7-epoxy-2-one, nardoguaianone K, nardonoxide, epoxynardosinone, 1(10)-isonardosinone-8-ol-9-one-7,11-lactone, valtrate isovaleroyloxyhydrine and nardostachin showed remarkable cytotoxicity against SW1990 cell lines with IC₅₀ values ranging from 0.07 ± 0.05 to 4.82 ± 6.96 μM. Furthermore, the primary mechanistic study of nardostachin demonstrated that it induced cell apoptosis via the mitochondria-dependent pathway, and induced SW1900 cell arrest at G2/M phase.

Abietane diterpenes from Abies spectabilis and their anti-pancreatic cancer activity against the MIA PaCa-2 cell line

An ethanolic extract of the stem of Abies spectabilis exhibited strong cytotoxicity against MIA PaCa-2 human pancreatic cancer cells preferentially under nutrient-deprived conditions. Therefore, phytochemical investigation of this bioactive extract was carried out, and that led the isolation of ten compounds (1-10) including a new abietane-type diterpene (1). The structure of the new compound (1) was elucidated by combined spectroscopic techniques, including HRFABMS, NMR and quantum ECD calculation. All the isolated compounds were evaluated for their efficacy against MIA PaCa-2 human pancreatic cancer cell line by employing an anti-austerity strategy. Among the tested compounds, dehydroabietinol (5) displayed the most potent activity with a PC50 value of 6.6 μM. Dehydroabietinol (5) was also found to retard the MIA PaCa-2 cell migration under normal nutrient-rich conditions displaying its anti-metastatic potential. Investigation on the mechanism suggested that dehydroabietinol (5) is an inhibitor of the key cancer cell survival Akt/mTOR/autophagy signaling pathway.

In Vitro Pharmacological Screening of Essential Oils from Baccharis parvidentata and Lippia origanoides Growing in Brazil

In this study, the in vitro antimicrobial, antiparasitic, antiproliferative and cytotoxic activities of essential oil from Baccharis parvidentata Malag. (EO-Bp) and Lippia origanoides Kunth (EO-Lo) were explored. The relevant effects were observed against the parasitic protozoans Plasmodium falciparum, Trypanosoma cruzi, Trypanosoma brucei and Leishmania amazonensis (ranging 0.6 to 39.7 µg/mL) and malignant MCF-7, MCF-7/HT, 22Rv1, and A431 cell lines (ranging 6.1 to 31.5 µg/mL). In parallel, EO-Bp showed better selective indexes in comparison with EO-Lo against peritoneal macrophages from BALB/c mice and MRC-5 cell line. In conclusion, EO-Lo is known to show a wide range of health benefits that could be added as another potential use of this oil with the current study. In the case of EO-Bp, the wide spectrum of its activities against protozoal parasites and malignant cells, as well as its selectivity in comparison with non-malignant cells, could suggest an interesting candidate for further tests as a new therapeutic alternative.

Antiproliferative potential of Physalis peruviana-derived magnolin against pancreatic cancer: a comprehensive in vitro and in silico study

Physalis peruviana L. is a common edible fruit in Egypt and other regional countries.

Structure-activity relationship and mechanistic study on guggulsterone derivatives; Discovery of new anti-pancreatic cancer candidate

Pancreatic cancer is one of the deadliest types of malignancies. A new intervention aiming to combat pancreatic cancer is targeting its extra-ordinary ability to tolerate nutrition starvation, a phenomenon known as "Austerity". As a part of a research program aiming to develop a new-generation of anticancer agents, known as "anti-austerity agents", guggulsterone derivatives (GSDs) were identified as unique anti-austerity agents in terms of potency and selectivity. These agents are able to exert preferential cytotoxic activity only under nutrient-deprived conditions with little or no toxicity under normal conditions. In the present study, a library of 14 GSDs was synthesized and screened against PANC-1 human pancreatic cells. Among tested compounds, GSD-11 showed the most potent activity with PC₅₀ a value of 0.72 μM. It also inhibited pancreatic cancer cell migration and colony formation in a concentration-dependent manner. A mechanistic study revealed that this compound can inhibit the activation of the Akt/mTOR signaling pathway. Therefore, GSD-11 could be a promising lead compound for the anticancer drug discovery against pancreatic cancer.