Mechanisms underlying the cytotoxicity of a novel quinazolinedione-based redox modulator, QD232, in pancreatic cancer cells

Bioactive Peptides: Potential Impact on the Treatment of Gastrointestinal Cancers

We have reviewed the potential use of bioactive peptides in the treatment of gastrointestinal (GI) malignancies, which are a significant cause of morbidity and mortality globally. Conventional therapies, such as surgery, chemotherapy, and radiotherapy, are associated with numerous side effects that may lead to longterm complications. Bioactive peptides are short-chain amino acids that can be extracted from natural sources or synthesized, and they have various potential health benefits, including anti-inflammatory, anti-hypertensive, antioxidant, antimicrobial, and anti-cancer properties. Bioactive peptides can be acquired from animal or plant sources, and can be classified based on their function, such as ACE-inhibiting, antimicrobial, and electrolyte- regulating peptides. Recent studies have demonstrated the promising role of bioactive peptides in tumor suppression, especially when combined with conventional therapies. In this study, we have reviewed the beneficial properties of bioactive peptides and their role in suppressing tumor activity. The mechanisms of bioactive peptides in tumor suppression are discussed. We have further reviewed the findings of preclinical and clinical studies that have investigated the application of bioactive peptides in the treatment of GI cancers. This review highlights the potential use of bioactive peptides as a promising treatment method for GI malignancies to increase the quality of life of GI cancer patients.

Green Synthesis and Electrochemical Properties of Mono- and Dimers Derived from Phenylaminoisoquinolinequinones

In the search for new quinoid compounds endowed with potential anticancer activity, the synthesis of novel heterodimers containing the cytotoxic 7-phenylaminoisoquinolinequinone and 2-phenylaminonaphthoquinone pharmacophores, connected through methylene and ethylene spacers, is reported. The heterodimers were prepared from their respective isoquinoline and naphthoquinones and 4,4'-diaminodiphenyl alkenes. The access to the target heterodimers and their corresponding monomers was performed both through oxidative amination reactions assisted by ultrasound and CeCl3·7H2O catalysis "in water". This eco-friendly procedure was successfully extended to the one-pot synthesis of homodimers derived from the 7-phenylaminoisoquinolinequinone pharmacophore. The electrochemical properties of the monomers and dimers were determined by cyclic and square wave voltammetry. The number of electrons transferred during the oxidation process, associated to the redox potential EI1/2, was determined by controlled potential coulometry.

Half-Wave Potentials and In Vitro Cytotoxic Evaluation of 3-Acylated 2,5-Bis(phenylamino)-1,4-benzoquinones on Cancer Cells

A broad range of 3-acyl-2,5-bis(phenylamino)-1,4-benzoquinones were synthesized and their voltammetric values, as well as in vitro cancer cell cytotoxicities, were assessed. The members of this series were prepared from acylbenzoquinones and phenylamines, in moderate to good yields (47–74%), through a procedure involving a sequence of two in situ regioselective oxidative amination reactions. The cyclic voltammograms of the aminoquinones exhibit two one-electron reduction waves to the corresponding radical-anion and dianion, and two quasi-reversible oxidation peaks. The first and second half-wave potential values (E_1/2) of the members of the series were sensitive to the push-pull electronic effects of the substituents around the benzoquinone nucleus. The in vitro cytotoxic activities of the 3-acyl-2,5-bis(phenylamino)-1,4-benzoquinones against human cancer cells (bladder and prostate) and non-tumor human embryonic kidney cells were measured using the MTT colorimetric method. The substitution of both aniline groups, by either methoxy (electron donating effect) or fluorine (electron withdrawal effect), decreased the cytotoxicity in the aminoquinones. Among the members of the unsubstituted phenylamino series, two of the 18 compounds showed interesting anti-cancer activities. A preliminary assay, looking for changes in the expression of selected genes, was performed. In this context, the two compounds increased TNF gene expression, suggesting an association with an inflammatory-like response.

Design and Synthesis of Novel Reactive Oxygen Species Inducers for the Treatment of Pancreatic Ductal Adenocarcinoma

Altering redox homeostasis provides distinctive therapeutic opportunities for the treatment of pancreatic cancer. Quinazolinediones (QDs) are novel redox modulators that we previously showed to induce potent growth inhibition in pancreatic ductal adenocarcinoma (PDAC) cell lines. Our lead optimization campaign yielded QD325 as the most potent redox modulator candidate inducing substantial reactive oxygen species (ROS) in PDAC cells. Nascent RNA sequencing following treatments with the QD compounds revealed induction of stress responses in nucleus, endoplasmic reticulum, and mitochondria of pancreatic cancer cells. Furthermore, the QD compounds induced Nrf2-mediated oxidative stress and unfolded protein responses as demonstrated by dose-dependent increases in RNA synthesis of representative genes such as NQO1, HMOX1, DDIT3, and HSPA5. At higher concentrations, the QDs blocked mitochondrial function by inhibiting mtDNA transcription and downregulating the mtDNA-encoded OXPHOS enzymes. Importantly, treatments with QD325 were well tolerated in vivo and significantly delayed tumor growth in mice. Our study supports the development of QD325 as a new therapeutic in the treatment of PDAC.

Chemoresistance in pancreatic cancer: Emerging concepts

Pancreatic cancer is one of the most lethal types of cancer in the world. The incidence of pancreatic cancer increases each year with no significant decrease in mortality. Pancreatic cancer is a complex disease, and this complexity is partly attributed to late diagnosis, an aggressive phenotype, environmental factors and lack of effective treatment options. Surgical resection followed by adjuvant chemotherapy is the treatment of choice for early stage cancer, whereas gemcitabine is the standard first line therapy for patients with advanced stage disease. Treatment regimens comprising folinic acid, 5-fluorouracil, irinotecan, oxaliplatin and nab-paclitaxel have demonstrated modest effects in improving median survival rates. A number of other chemotherapeutics are currently undergoing clinical trials as components of combination therapies with gemcitabine. An increasing number of novel molecular targets and cellular pathways are being identified, which highlights the complexity of this disease. The development of chemoresistance to gemcitabine is multifactorial and there exists an interplay between pancreatic cancer cells, the tumor microenvironment and cancer stem cells. These components appear to be governed by a complex network of non-coding RNAs such as micro RNAs and long non-coding RNAs. In the present study, studies describing previous research on the understanding of the factors associated with the development of chemoresistance to gemcitabine in pancreatic cancer are reviewed. A comprehensive understanding of the multiple pathways of chemoresistance is key to develop next generation therapeutics to pancreatic cancer.