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Phthalocyanines (Pcs) are promising candidates for photodynamic therapy (PDT) due to their absorption in the phototherapeutic window. However, the highly aromatic Pc core leads to undesired aggregation and decreased reactive oxygen species (ROS) production. Therefore, short PEG chain functionalized A3B type asymmetric Pc photosensitizers (PSs) were designed in order to decrease aggregation and increase the aqueous solubility. Here we report the synthesis, characterization, optical properties, cellular localization, and cytotoxicity of three novel Pc-based agents (LC31, MLC31, and DMLC31Pt). The stepwise functionalization of the peripheral moieties has a strong effect on the distribution coefficient (logP), cellular uptake, and localization, as well as photocytotoxicity. Additional experiments have revealed that the presence of the malonic ester moiety in the reported agent series is indispensable in order to induce photocytotoxicity. The best-performing agent, MLC31, showed mitochondrial targeting and an impressive phototoxic index (p.i.) of 748 in the cisplatin-resistant A2780/CP70 cell line, after a low-dose irradiation of 6.95 J/cm2. This is the result of a high photocytotoxicity (IC50 = 157 nM) upon irradiation with near-infrared (NIR) light, and virtually no toxicity in the dark (IC50 = 117 μM). Photocytotoxicity was subsequently determined under hypoxic conditions. Additionally, a preliminarily pathway investigation of the mitochondrial membrane potential (MMP) disruption and induction of apoptosis by MLC31 was carried out. Our results underline how agent design involving both hydrophilic and lipophilic peripheral groups may serve as an effective way to improve the PDT efficiency of highly aromatic PSs for NIR light-mediated cancer therapy.

Phthalocyanines (Pcs) are promising candidates for photodynamic therapy (PDT) due to their absorption in the phototherapeutic window. However, the highly aromatic Pc core leads to undesired aggregation and decreased reactive oxygen species (ROS) production. Therefore, short PEG chain functionalized A

We report the first exocyclically metallated tetrapyridinoporphyrazine, [tetrakis-(trans-Pt(NH3)2Cl)-tetra(3,4-pyrido)porphyrazine-zinc(II)](NO3)4 (4), synthesized in a multistep synthesis starting from 3,4-pyridinedicarbonitrile (1). The synthetic procedure involved a platination reaction of the intermediate tetra(3,4-pyrido)porphyrazine-zinc(II) (2), whereby the zinc(II) enhanced the solubility of the intermediate enabling the platination reaction. A similar approach to synthesize [tetrakis-(trans-Pt(NH3)2Cl)-tetra(3,4-pyrido)porphyrazine](NO3)4 (5) failed due to the unsuitable solubility properties of the intermediate tetra(3,4-pyrido)porphyrazine (3). The final product 4 and the intermediates were characterized, the photochemical and photophysical properties were determined and the photocytotoxicities were investigated. We demonstrate that the platinated tetra-pyridinoporphyrazine 4 is a potential photosensitizer for photodynamic therapy (PDT).

In this study, we addressed an important drawback of our previously reported tetraplatinated (metallo)porphyrin-based photosensitizers (PSs) for photodynamic therapy (PDT), namely, the poor solubility in aqueous media. We aimed to create tetraplatinated porphyrin-based PSs that are soluble in aqueous media modified with polysorbate (Tween) and do not need to be pre-dissolved in organic solvents. A structural optimization of the previously reported PSs resulted in the synthesis of an extremely potent novel porphyrin-based PS. The novel PS displays effective phototoxicity upon light irradiation against multicellular tumor spheroids and has a phototoxic index (PI) of 6030 in HeLa cells. This PI value is, to the best of our knowledge, the highest value reported for any porphyrin so far.

Photodynamic therapy (PDT) is used to treat various cancerous diseases. Recently, we have demonstrated that platinated pyridyl-substituted porphyrins are potent agents for PDT with very high phototoxicity (IC50 down to 17 nM) and excellent phototoxic indices of higher than 5800 (p.i. = IC50(dark)/IC50(light)) [Rubbiani, R. et al., Chem. Commun. 2020, 56, 14373]. However, the absorption of porphyrins is not ideal for the treatment of larger tumors because they essentially do not absorb light between 650 and 850 nm. Herein, we report stable conjugates of a novel bacteriochlorin with cisplatin and transplatin. They exhibit extremely high phototoxicity (IC50 values down to 6 nM, irradiated with a 750 nm LED at a fluence of 5 J/cm2), very low dark toxicity, and thereby extremely high phototoxic indices up to 8300. Based on these exciting results, we believe that platinated bacteriochlorins are promising candidates for further investigation as novel PDT anticancer agents.

We report the synthesis of novel tetraplatinated metalloporphyrin-based photosensitizers (PSs) for photodynamic therapy (PDT), their characterization, cellular uptake and localization, as well as the determination of their in vitro light-induced anticancer properties. The PSs show excellent phototoxic indexes up to 5800 against HeLa cells, which is, to the best of our knowledge, the highest value reported for any porphyrin so far. Furthermore, isotopic labelling of the porphyrin with a highly enriched 67Zn isotope was performed in order to determine the distribution ratio of zinc to platinum by ICP-MS, allowing to differentiate between naturally occurring zinc and 67Zn that was introduced into the cells by the PS. We conclude that the platinum units within the platinum-PS conjugates help to solubilize the PS and, at the same time, act as cell-penetrating vectors, enhancing the efficiency of the PS without causing a significant dark toxicity.

Summary DNA damage causally contributes to aging and age-related diseases. Mutations in nucleotide excision repair (NER) genes cause highly complex congenital syndromes characterized by growth retardation, cancer susceptibility, and accelerated aging in humans. Orthologous mutations in Caenorhabditis elegans lead to growth delay, genome instability, and accelerated functional decline, thus allowing investigation of the consequences of persistent DNA damage during development and aging in a simple metazoan model. Here, we conducted proteome, lipidome, and phosphoproteome analysis of NER-deficient animals in response to UV treatment to gain comprehensive insights into the full range of physiological adaptations to unrepaired DNA damage. We derive metabolic changes indicative of a tissue maintenance program and implicate an autophagy-mediated proteostatic response. We assign central roles for the insulin-, EGF-, and AMPK-like signaling pathways in orchestrating the adaptive response to DNA damage. Our results provide insights into the DNA damage responses in the organismal context., Graphical Abstract, Highlights • Proteome responses to persistent DNA damage correlate with starvation and aging • Proteostatic shift reduces ubiquitin proteasome and chaperones and relies on autophagy • Metabolic adaptations to DNA damage reduce fatty acid synthesis • Insulin-, EGF-, and AMPK-like signaling pathways respond to UV-induced DNA damage, Edifizi et al. provide a comprehensive proteomics, phosphoproteomics, and lipidomics analysis of the response to persistent DNA damage in a metazoan organism. Proteostasis shifts toward autophagy, fatty acid metabolism is attenuated, and the insulin-, EGF-, and AMPK-like signaling pathways form the center of the response network.

Cockayne syndrome (CS) is a debilitating and complex disorder that results from inherited mutations in the CS complementation genes A and B, CSA and CSB. The links between the molecular functions of the CS genes and the complex pathophysiology of CS are as of yet poorly understood and are the subject of intense debate. While mouse models reflect the complexity of CS, studies on simpler genetic models might shed new light on the consequences of CS mutations. Here we describe a functional homolog of the human CSA gene in Caenorhabditis elegans. Similar to its human counterpart, mutations in the nematode csa-1 gene lead to developmental growth defects as a consequence of DNA lesions.

Genome maintenance defects cause complex disease phenotypes characterized by developmental failure, cancer susceptibility and premature ageing. It remains poorly understood how DNA damage responses function during organismal development and maintain tissue functionality when DNA damage accumulates with ageing. Here we show that the FOXO transcription factor DAF-16 is activated in response to DNA damage during development, whereas the DNA damage responsiveness of DAF-16 declines with ageing. We find that in contrast to its established role in mediating starvation arrest, DAF-16 alleviates DNA-damage-induced developmental arrest and even in the absence of DNA repair promotes developmental growth and enhances somatic tissue functionality. We demonstrate that the GATA transcription factor EGL-27 co-regulates DAF-16 target genes in response to DNA damage and together with DAF-16 promotes developmental growth. We propose that EGL-27/GATA activity specifies DAF-16-mediated DNA damage responses to enable developmental progression and to prolong tissue functioning when DNA damage persists.

The transcription-coupled repair pathway (TC-NER) plays a vital role in removing transcription-blocking DNA lesions, particularly UV-induced damage. Clinical symptoms of the two TC-NER-deficiency syndromes, Cockayne syndrome (CS) and UV-hypersensitivity syndrome (UVSS) are dissimilar and the underlying molecular mechanism causing this difference in disease pathology is not yet clearly understood. UV-stimulated scaffold protein A (UVSSA) has been identified recently as a new causal gene for UVSS. Here we describe a functional homolog of the human UVSSA gene in the nematode Caenorhabditis elegans, uvs-1 (UVSSA-like-1). Mutations in uvs-1 render the animals hypersensitive to UV-B irradiation and transcription-blocking lesion-inducing illudin-M, similar to mutations in TC-NER deficient mutants. Moreover, we demonstrate that TC-NER factors including UVS-1 are required for the survival of the adult animals after UV-treatment.

Treatment resistance becomes a challenge at some point in the course of most patients with chronic lymphocytic leukemia (CLL). This applies to fludarabine-based regimens, and is also an increasing concern in the era of more targeted therapies. As cells with low-replicative activity rely on repair that triggers checkpoint-independent noncanonical pathways, we reasoned that targeting the nucleotide excision repair (NER) reaction addresses a vulnerability of CLL and might even synergize with fludarabine, which blocks the NER gap-filling step. We interrogated here especially the replication-independent transcription-coupled-NER ((TC)-NER) in prospective trial patients, primary CLL cultures, cell lines and mice. We screen selected (TC)-NER-targeting compounds as experimental (illudins) or clinically approved (trabectedin) drugs. They inflict transcription-stalling DNA lesions requiring TC-NER either for their removal (illudins) or for generation of lethal strand breaks (trabectedin). Genetically defined systems of NER deficiency confirmed their specificity. They selectively and efficiently induced cell death in CLL, irrespective of high-risk cytogenetics, IGHV status or clinical treatment history, including resistance. The substances induced ATM/p53-independent apoptosis and showed marked synergisms with fludarabine. Trabectedin additionally perturbed stromal-cell protection and showed encouraging antileukemic profiles even in aggressive and transforming murine CLL. This proof-of-principle study established (TC)-NER as a mechanism to be further exploited to resensitize CLL cells.