A phase II study of Irofulven (MGI 114) in patients with stage IV melanoma

The mutational impact of Illudin S on human cells

Illudin S (ILS) is a fungal sesquiterpene secondary metabolite with potent genotoxic and cytotoxic properties. Early genetic studies and more recent genome-wide CRISPR screens showed that Illudin-induced lesions are preferentially repaired by transcription-coupled nucleotide excision repair (TC-NER) with some contribution from post-replication repair pathways. In line with these results, Irofulven, a semi-synthetic ILS analog was recently shown to be particularly effective on cell lines and patient-derived xenografts with impaired NER (e.g. ERCC2/3 mutations), raising hope that ILS-derived molecules may soon enter the clinic. Despite the therapeutic potential of ILS and its analogs, we still lack a global understanding of their mutagenic potential. Here, we characterize the mutational signatures associated with chronic exposure to ILS in human cells. ILS treatment rapidly stalls DNA replication and transcription, leading to the activation of the replication stress response and the accumulation of DNA damage. Novel single and double base substitution signatures as well as a characteristic indel signature indicate that ILS treatment preferentially alkylates purine residues and induces oxidative stress, confirming prior in vitro data. Many mutation contexts exhibit a strong transcriptional strand bias, highlighting the contribution of TC-NER to the repair of ILS lesions. Finally, collateral mutations are also observed in response to ILS, suggesting a contribution of translesion synthesis pathways to ILS tolerance. Accordingly, ILS treatment led to the rapid recruitment of the Y-family DNA polymerase kappa onto chromatin, supporting its preferential use for ILS lesion bypass. Altogether, our work provides the first global assessment of the genomic impact of ILS, demonstrating the contribution of multiple DNA repair pathways to ILS resistance and mutagenicity.

Mushrooms: an emerging resource for therapeutic terpenoids

Mankind has always been fascinated with nature and have heavily explored natural products since the ancient times. Evolution of diseases led to research on synthetic structure, specificity and activity-guided treatment. To combat threats of new developing diseases and the deleterious side effects posed by modern therapy, researchers have once again looked back towards natural resources. Although plants have been the main source of natural drugs, lower fungi are being recently paid attention to. Among them, mushrooms have emerged as an under-explored yet immensely rich resource, especially for bioactive terpenoids. A lot of research is going on around the world with mushroom-derived terpenoids especially their medicinal properties, some of which have even been used in pre- and post-clinical studies. From the literatures that are available, it was found that mushroom terpenoids have activity against a wide range of diseases. In this review, we have summarized different mushroom-derived terpenoids and their therapeutic properties.

New cytotoxic agents: a review of the literature

The goal of treatment for patients with advanced cancer is to prolong survival, control symptoms, and reduce disease-related complications. Despite the introduction of many cytotoxic agents during the past decade, only modest improvement in survival has been achieved. In order to urgently improve these situations, new cytotoxic agents as well as molecular-targeted agents are now under investigation. In this article, we reviewed the latest information regarding antitumor activity, toxicity, pharmacokinetics, and clinical application of the new cytotoxic agents.

Medicinal mushroom modulators of molecular targets as cancer therapeutics

Empirical approaches to discover anticancer drugs and cancer treatments have made limited progress in the past several decades in finding a cure for cancer. The expanded knowledge of the molecular basis of tumorigenesis and metastasis, together with the inherently vast structural diversity of natural compounds found in mushrooms, provided unique opportunities for discovering new drugs that rationally target the abnormal molecular and biochemical signals leading to cancer. This review focuses on mushroom low-molecular-weight secondary metabolites targeting processes such as apoptosis, angiogenesis, metastasis, cell cycle regulation, and signal transduction cascades. Also discussed in this review are high-molecular-weight polysaccharides or polysaccharide-protein complexes from mushrooms that appear to enhance innate and cell-mediated immune responses, exhibit antitumor activities in animals and humans, and demonstrate the anticancer properties of selenium compounds accumulated in mushrooms.