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

Toyaburgine, a Synthetic N-Biphenyl-Dihydroisoquinoline Inspired by Related N,C-Coupled Naphthylisoquinoline Alkaloids, with High In Vivo Efficacy in Preclinical Pancreatic Cancer Models

Pancreatic cancer is a highly aggressive and lethal malignancy, with a 5-year survival rate below 10%. Traditional chemotherapy, including gemcitabine, has limited efficacy due to chemoresistance and a unique tumor microenvironment characterized by hypovascularity and nutrient deprivation. This study reports on the discovery of a new N-biphenyl-dihydroisoquinoline, named toyaburgine (4), inspired by naturally occurring N,C-coupled naphthylisoquinoline alkaloids. Developed through systematic structural optimization, toyaburgine is a potent anticancer agent, showing promise for pancreatic cancer treatment. It exhibits strong antiausterity activity with low nanomolar PC50 values, effectively inhibiting pancreatic cancer cell viability under nutrient-deprived conditions. In vitro, 4 causes significant morphological changes and cancer cell death in MIA PaCa-2 cells while also inhibiting cell migration and colony formation, which indicates its antimetastatic potential. Mechanistically, toyaburgine disrupts the PI3K/Akt/mTOR pathway, essential for pancreatic cancer cell survival in a stressful microenvironment, and inhibits MIA PaCa-2 spheroid formation. In vivo, toyaburgine, alone or combined with gemcitabine, shows effective tumor suppression in subcutaneous xenograft and clinically relevant orthotopic models, where it also reduces cachexia. These results highlight the potential of toyaburgine as a new therapeutic drug for pancreatic cancer. Its combination with gemcitabine presents a promising treatment approach by targeting both proliferating and gemcitabine-resistant cancer cells.

Effectiveness of phytoproducts against pathogenic free-living amoebae - A scoping and critical review paving the way toward plant-based pharmaceuticals

Infections caused by free-living amoebae (FLA) have increased worldwide and are expected to worsen. The lack of drugs that are effective (especially against cysts), affordable, and safe to treat these infections exacerbates the concern. Plants present a promising source of bioactive compounds for developing effective drugs; however, the scientific literature on this topic has yet to be adequately synthesized. This work provides a critical scoping review summarizing the amoebicidal performance of plant-derived products and their potential for developing effective drugs to treat FLA infections. Out of 5889 articles retrieved from multiple databases, 119 articles were selected, from which data on 180 plant species belonging to 127 genera and 62 families were extracted. The extracts, essential oils, and compounds from these plants exhibited a diverse range of potency against cysts and trophozoites. Among the compounds studied, periglaucine A, kolavenic acid, and (+)-elatol are promising cysticidal drug candidates due to their high potency, as well as their known low toxicity to non-target cells. Tovophillin A, gartinin, 8-deoxygartinin, garcinone E, 9-hydroxycalabaxanthone, γ-mangostin, and borneol also exhibit high cysticidal potency, but their selectivity profile is unknown. Resveratrol, rosmarinic acid, β-amyrin, and vanillic acid stand out for their high potency against trophozoites and low toxicity to mammalian cells. Another group of compounds with similarly high trophocidal potency includes (-)-epicatechin, (-)-epigallocatechin, apigenin, costunolide, demethoxycurcumin, kaempferol, methyl-β-orcinolcarboxylate, sakuraetin, (+)-elatol, debromolaurinterol, luteolin, (-)-rogiolol, cystomexicone B, epigallocatechin gallate, quercetin, and α-bisabolol. These compounds are priority candidates for further studies on in vivo efficacy, safety, pharmacokinetics, and pharmacodynamics.

Targeting Pancreatic Cancer with Novel Nicolaioidesin C Derivatives: Molecular Mechanism, In Vitro, and In Vivo Evaluations

Pancreatic cancer, one of the deadliest cancers with the lowest 5-year survival rate, often develops resistance to gemcitabine-based chemotherapies. The hypovascular nature of pancreatic tumors forces cancer cells to adapt to nutrient-depleted tumor microenvironments. Conventional anticancer agents targeting rapidly dividing cancer cells under nutrient-rich conditions are largely ineffective against adapted pancreatic cancer cells. Thus, targeting cancer cells under nutrient starvation, termed the "antiausterity strategy", may be effective for pancreatic cancer. This study examined nicolaioidesin C (Nic-C) derivatives as antiausterity agents. Among the 32 derivatives, Nic-15 (4n) exhibited superior cytotoxicity against MIA PaCa-2 and PANC-1 pancreatic cancer cells, inhibited MIA PaCa-2 cell migration and colony formation, and modulated the PI3K/Akt/mTOR pathway, while reducing the ER stress markers induced by gemcitabine. Nic-15 was found to inhibit tumor growth and enhance the efficacy of gemcitabine in an in vivo xenograft model. Nic-15 in combination with gemcitabine may be an effective strategy for the treatment of pancreatic cancer.

Substrate-Dependent Alteration in the C- and O-Prenylation Specificities of Cannabis Prenyltransferase

CsPT4 is an aromatic prenyltransferase that synthesizes cannabigerolic acid (CBGA), the key intermediate of cannabinoid biosynthesis in Cannabis sativa, from olivetolic acid (OA) and geranyl diphosphate (GPP). CsPT4 has a catalytic potential to produce a variety of CBGA analogs via regioselective C-prenylation of aromatic substrates having resorcylic acid skeletons including bibenzyl 2,4-dihydroxy-6-phenylethylbenzoic acid (DPA). In this study, we further investigated the substrate specificity of CsPT4 using phlorocaprophenone (PCP) and 2',4',6'-trihydroxydihydrochalcone (THDC), the isomers of OA and DPA, respectively, and demonstrated that CsPT4 catalyzed both C-prenylation and O-prenylation reactions on PCP and THDC that share acylphloroglucinol substructures. Interestingly, the kinetic parameters of CsPT4 for these substrates differed depending on whether they underwent C-prenylation or O-prenylation, suggesting that this enzyme utilized different substrate-binding modes suitable for the respective reactions. Aromatic prenyltransferases that catalyze O-prenylation are rare in the plant kingdom, and CsPT4 was notable for altering the reaction specificity between C- and O-prenylations depending on the skeletons of aromatic substrates. We also demonstrated that enzymatically synthesized geranylated acylphloroglucinols had potent antiausterity activity against PANC-1 human pancreatic cancer cells, with 4'-O-geranyl THDC being the most effective. We suggest that CsPT4 is a valuable catalyst to generate biologically active C- and O-prenylated molecules that could be anticancer lead compounds.