Basal microvilli define the metabolic capacity and lethal phenotype of pancreatic cancer

From oncolytic peptides to oncolytic polymers: A new paradigm for oncotherapy

Traditional cancer therapy methods, especially those directed against specific intracellular targets or signaling pathways, are not powerful enough to overcome tumor heterogeneity and therapeutic resistance. Oncolytic peptides that can induce membrane lysis-mediated cancer cell death and subsequent anticancer immune responses, has provided a new paradigm for cancer therapy. However, the clinical application of oncolytic peptides is always limited by some factors such as unsatisfactory bio-distribution, poor stability, and off-target toxicity. To overcome these limitations, oncolytic polymers stand out as prospective therapeutic materials owing to their high stability, chemical versatility, and scalable production capacity, which has the potential to drive a revolution in cancer treatment. This review provides an overview of the mechanism and structure-activity relationship of oncolytic peptides. Then the oncolytic peptides-mediated combination therapy and the nano-delivery strategies for oncolytic peptides are summarized. Emphatically, the current research progress of oncolytic polymers has been highlighted. Lastly, the challenges and prospects in the development of oncolytic polymers are discussed.

Evaluating the In Vitro Activity and Safety of Modified LfcinB Peptides as Potential Colon Anticancer Agents: Cell Line Studies and Insect-Based Toxicity Assessments

Anticancer peptides are increasingly being considered as alternative treatments for cancer due to their potency, selectivity, and low toxicity. Previously, the peptide LfcinB (21-25)Pal showed in vitro anticancer effects against the Caco-2 colon cancer cell line (half-maximal inhibitory concentration (IC50): 86 μM). In this study, we developed modifications to the peptide sequence to increase its anticancer activity. Sequence modifications were made such as the inclusion of amino hexanoic acid (Ahx), N-terminal biotinylation, acetylation, and substitutions of Orn for Arg and/or d-Arg by l-Arg. The molecules were synthesized using manual solid-phase peptide synthesis (SPPS), and their synthetic feasibility (SAScore) ranged from 6.2 to 7.6. The chromatographic purities of the synthesized peptides were greater than 89%. We found that Ahx-RWQWRWQWR and RWQWRWQW-Orn showed activity against both Caco-2 and HT-29 cell lines and decreased IC50 values by approx. 50% in Caco-2 cells (IC50: 40 μM) when compared to the parent peptide RWQWRWQWR. Moreover, the modified peptides demonstrated lower hemolytic effects, with values <10% at 200 μg/mL. Toxicity was assessed using the Galleria mellonella model and the half-maximal lethal dose (LD50) for the best peptides was >100 mg/kg, indicating that their toxicity is classified as moderately toxic or lower. In contrast, cisplatin showed an LD50 of 13 mg/Kg. The designed anticancer peptides presented good in vitro activity and low toxicity, making them promising molecules for future drug development studies.

Therapeutic advances targeting tumor angiogenesis in pancreatic cancer: Current dilemmas and future directions

Pancreatic cancer (PC) is one of the most lethal malignancies, which is generally resistant to various treatments. Tumor angiogenesis is deemed to be a pivotal rate-determining step for tumor growth and metastasis. Therefore, anti-angiogenetic therapy is a rational strategy to treat various cancers. However, numerous clinical trials on anti-angiogenetic therapies for PC are overwhelmingly disappointing. The unique characteristics of tumor blood vessels in PC, which are desperately lacking and highly compressed by the dense desmoplastic stroma, are reconsidered to explore some optimized strategies. In this review, we mainly focus on its specific characteristics of tumor blood vessels, discuss the current dilemmas of anti-angiogenic therapy in PC and their underlying mechanisms. Furthermore, we point out the future directions, including remodeling the abnormal vasculature or even reshaping the whole tumor microenvironment in which they are embedded to improve tumor microcirculation, and then create therapeutic vulnerabilities to the current available therapeutic strategies.

Melatonin modulates the Warburg effect and alters the morphology of hepatocellular carcinoma cell line resulting in reduced viability and migratory potential

AIMS

Hepatocellular Carcinoma (HCC) is a primary neoplasm derived from hepatocytes with low responsiveness and recurrent chemoresistance. Melatonin is an alternative agent that may be helpful in treating HCC. We aimed to study in HuH 7.5 cells whether melatonin treatment exerts antitumor effects and, if so, what cellular responses are induced and involved.

MAIN METHODS

We evaluated the effects of melatonin on cell cytotoxicity and proliferation, colony formation, morphological and immunohistochemical aspects, and on glucose consumption and lactate release.

KEY FINDINGS

Melatonin reduced cell motility and caused lamellar breakdown, membrane damage, and reduction in microvillus. Immunofluorescence analysis revealed that melatonin reduced TGF and N-cadherin expression, which was further associated with inhibition of epithelial-mesenchymal transition process. In relation to the Warburg-type metabolism, melatonin reduced glucose uptake and lactate production by modulating intracellular lactate dehydrogenase activity.

SIGNIFICANCE

Our results indicate that melatonin can act upon pyruvate/lactate metabolism, preventing the Warburg effect, which may reflect in the cell architecture. We demonstrated the direct cytotoxic and antiproliferative effect of melatonin on the HuH 7.5 cell line, and suggest that melatonin is a promising candidate to be further tested as an adjuvant to antitumor drugs for HCC treatment.

Construction of a pancreatic cancer nerve invasion system using brain and pancreatic cancer organoids

Pancreatic cancer (PC) is a fatal malignancy in the human abdominal cavity that prefers to invade the surrounding nerve/nerve plexus and even the spine, causing devastating and unbearable pain. The limitation of available in vitro models restricts revealing the molecular mechanism of pain and screening pain-relieving strategies to improve the quality of life of end-stage PC patients. Here, we report a PC nerve invasion model that merged human brain organoids (hBrO) with mouse PC organoids (mPCO). After merging hBrOs with mPCOs, we monitored the structural crosstalk, growth patterns, and mutual interaction dynamics of hBrO with mPCOs for 7 days. After 7 days, we also analyzed the pathophysiological statuses, including proliferation, apoptosis and inflammation. The results showed that mPCOs tend to approximate and intrude into the hBrOs, merge entirely into the hBrOs, and induce the retraction/shrinking of neuronal projections that protrude from the margin of the hBrOs. The approximating of mPCOs to hBrOs accelerated the proliferation of neuronal progenitor cells, intensified the apoptosis of neurons in the hBrOs, and increased the expression of inflammatory molecules in hBrOs, including NLRP3, IL-8, and IL-1β. Our system pathophysiologically replicated the nerve invasions in mouse GEMM (genetically engineered mouse model) primary and human PCs and might have the potential to be applied to reveal the molecular mechanism of nerve invasion and screen therapeutic strategies in PCs.

IDO-1 inhibitor INCB24360 elicits distant metastasis of basal extruded cancer cells in pancreatic ductal adenocarcinoma

Neoplastic cells of non-immunogenic pancreatic ductal adenocarcinoma (PDAC) express indoleamine 2,3-dioxygenase 1 (IDO-1), an immunosuppressive enzyme. The metabolites of IDO-1 in cancers provide one-carbon units that annihilate effector T cells, and recruit immunosuppressive cells. In this study we investigated how IDO-1 affected the neoplastic cell behaviors in PDACs. Using multiple markers co-labeling method in 45-µm-thick tissue sections, we showed that IDO-1 expression was uniquely increased in the neoplastic cells extruded from ducts’ apical or basal domain, but decreased in lymph metastatic cells. IDO-1+ extruding neoplastic cells displayed increased vimentin expression and decreased cytokeratin expression in PDACs, characteristics of epithelial-mesenchymal transition (EMT). However, IDO-1 expression was uncorrelated with immunosuppressive infiltrates and clinicopathological characteristics of grim outcome. We replicated basal extrusion with EMT in murine KPIC PDAC organoids by long-term IFN-γ induction; application of IDO-1 inhibitor INCB24360 or 1-MT partially reversed basal extrusion coupled EMT. Ido-1 deletion in KPIC cells deprived its tumorigenicity in immunocompetent mice, decreased cellular proliferation and macropinocytic ability, and increased immunogenicity. KPIC organoids with IFN-γ-induced basal extrusion did not accelerate distant metastasis, whereas inhibition IFN-γ-induced IDO-1 with INB24360 but not 1-MT in KPIC organoids elicited liver metastasis of subcutaneous KPIC organoid tumors, suggesting that lower IDO-1 activity accelerated distant metastasis, whereas IDO-1 was indispensable for tumorigenicity of PDAC cells and supports the survival of extruding cells.

Bioactive cationic peptides as potential agents for breast cancer treatment

Breast cancer continues to affect millions of women worldwide, and the number of new cases dramatically increases every year. The physiological causes behind the disease are still not fully understood. One in every 100 cases can occur in men, and although the frequency is lower than among women, men tend to have a worse prognosis of the disease. Various therapeutic alternatives to combat the disease are available. These depend on the type and progress of the disease, and include chemotherapy, radiotherapy, surgery, and cancer immunotherapy. However, there are several well-reported side effects of these treatments that have a significant impact on life quality, and patients either relapse or are refractory to treatment. This makes it necessary to develop new therapeutic strategies. One promising initiative are bioactive peptides, which have emerged in recent years as a family of compounds with an enormous number of clinical applications due to their broad spectrum of activity. They are widely distributed in several organisms as part of their immune system. The antitumoral activity of these peptides lies in a nonspecific mechanism of action associated with their interaction with cancer cell membranes, inducing, through several routes, bilayer destabilization and cell death. This review provides an overview of the literature on the evaluation of cationic peptides as potential agents against breast cancer under different study phases. First, physicochemical characteristics such as the primary structure and charge are presented. Secondly, information about dosage, the experimental model used, and the mechanism of action proposed for the peptides are discussed.