A modified arginine-depleting enzyme NEI-01 inhibits growth of pancreatic cancer cells

Development of a bioengineered Erwinia chrysanthemi asparaginase to enhance its anti-solid tumor potential for treating gastric cancer

Asparaginase has been traditionally applied for only treating acute lymphoblastic leukemia due to its ability to deplete asparagine. However, its ultimate anticancer potential for treating solid tumors has not yet been unleashed. In this study, we bioengineered Erwinia chrysanthemi asparaginase (ErWT), one of the US Food and Drug Administration-approved types of amino acid depleting enzymes, to achieve double amino acid depletions for treating a solid tumor. We constructed a fusion protein by joining an albumin binding domain (ABD) to ErWT via a linker (GGGGS)5 to achieve ABD-ErS5. The ABD could bind to serum albumin to form an albumin-ABD-ErS5 complex, which could avoid renal clearance and escape from anti-drug antibodies, resulting in a remarkably prolonged elimination half-life of ABD-ErS5. Meanwhile, ABD-ErS5 did not only deplete asparagine but also glutamine for ∼2 weeks. A biweekly administration of ABD-ErS5 (1.5 mg/kg) significantly suppressed tumor growth in an MKN-45 gastric cancer xenograft model, demonstrating a novel approach for treating solid tumor depleting asparagine and glutamine. Multiple administrations of ABD-ErS5 did not cause any noticeable histopathological abnormalities of key organs, suggesting the absence of acute toxicity to mice. Our results suggest ABD-ErS5 is a potential therapeutic candidate for treating gastric cancer.

Unlocking the Potential of Arginine Deprivation Therapy: Recent Breakthroughs and Promising Future for Cancer Treatment

Arginine is a semi-essential amino acid that supports protein synthesis to maintain cellular functions. Recent studies suggest that arginine also promotes wound healing, cell division, ammonia metabolism, immune system regulation, and hormone biosynthesis-all of which are critical for tumor growth. These discoveries, coupled with the understanding of cancer cell metabolic reprogramming, have led to renewed interest in arginine deprivation as a new anticancer therapy. Several arginine deprivation strategies have been developed and entered clinical trials. The main principle behind these therapies is that arginine auxotrophic tumors rely on external arginine sources for growth because they carry reduced key arginine-synthesizing enzymes such as argininosuccinate synthase 1 (ASS1) in the intracellular arginine cycle. To obtain anticancer effects, modified arginine-degrading enzymes, such as PEGylated recombinant human arginase 1 (rhArg1-PEG) and arginine deiminase (ADI-PEG 20), have been developed and shown to be safe and effective in clinical trials. They have been tried as a monotherapy or in combination with other existing therapies. This review discusses recent advances in arginine deprivation therapy, including the molecular basis of extracellular arginine degradation leading to tumor cell death, and how this approach could be a valuable addition to the current anticancer arsenal.

Arginine deprivation as a treatment approach targeting cancer cell metabolism and survival: A review of the literature

Amino acid requirement of metabolically active cells is a key element in cellular survival. Of note, cancer cells were shown to have an abnormal metabolism and high-energy requirements including the high amino acid requirement needed for growth factor synthesis. Thus, amino acid deprivation is considered a novel approach to inhibit cancer cell proliferation and offer potential treatment prospects. Accordingly, arginine was proven to play a significant role in cancer cell metabolism and therapy. Arginine depletion induced cell death in various types of cancer cells. Also, the various mechanisms of arginine deprivation, e.g., apoptosis and autophagy were summarized. Finally, the adaptive mechanisms of arginine were also investigated. Several malignant tumors had high amino acid metabolic requirements to accommodate their rapid growth. Antimetabolites that prevent the production of amino acids were also developed as anticancer therapies and are currently under clinical investigation. The aim of this review is to provide a concise literature on arginine metabolism and deprivation, its effects in different tumors, its different modes of action, as well as the related cancerous escape mechanisms.

When AIE meets enzymes

Applications of AIEgens in biosensing, disease diagnosis, and drug release.

NEI-01-Induced Arginine Deprivation Has Potent Activity Against Acute Myeloid Leukemia Cells Both In Vitro and In Vivo

Recent studies have revealed that targeting amino acid metabolic enzymes is a promising strategy in cancer therapy. Acute myeloid leukemia (AML) downregulates the expression of argininosuccinate synthase (ASS1), a recognized rate-limiting enzyme for arginine synthesis, and yet displays a critical dependence on extracellular arginine for survival and proliferation. This dependence on extracellular arginine, also known as arginine auxotrophy, suggests that arginine deprivation would be a treatment strategy for AML. NEI-01, a novel arginine-depleting enzyme, is capable of binding to serum albumin to extend its circulating half-life, leading to a potent anticancer activity. Here we reported the preclinical activity of NEI-01 in arginine auxotrophic AMLs. NEI-01 efficiently depleted arginine both in vitro and in vivo NEI-01-induced arginine deprivation was cytotoxic to arginine auxotrophic AML cells through induction of cell-cycle arrest and apoptosis. Furthermore, the potent anti-leukemia activities of NEI-01 were observed in three different types of mouse models including human cell line-derived xenograft, mouse cell line-derived homografts in syngeneic mice and patient-derived xenograft. This preclinical data provide strong evidence to support the potential use of NEI-01 as a therapeutic approach in AML treatment.

Arginine deprivation as a strategy for cancer therapy: An insight into drug design and drug combination

Extensive studies have shown that cancer cells have specific nutrient auxotrophy and thus have much a higher demand for certain nutrients than normal cells. Amino acid deprivation has attracted much attention in cancer therapy with positive outcomes from clinical trials. Arginine, as one of the conditionally essential amino acids, plays a pivotal role in cellular division and metabolism. Since many types of cancer cells exhibit decreased expression of argininosuccinate synthetase and/or ornithine transcarbamylase, they are auxotrophic for arginine, which makes arginine deprivation an accessible choice for cancer treatment. Arginine deiminase (ADI) and human arginase (hArg) are the two major protein drugs used for arginine deprivation and are undergoing many clinical trials. However, the clinical application of ADI and hArg is facing some common problems, including their short half-lives, immunogenicity and inconsistent production, which underlines the importance of improving these drugs using protein engineering techniques. Thus, we systematically review the latest studies of protein engineering and anti-cancer studies based on in vitro, in vivo and clinical models of ADI and hArg, and we include the latest studies on drug combinations consisting of ADI/hArg with chemotherapeutic drugs.