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Bioorganic Chemistry Feb 2024Photodynamic therapy (PDT) has emerged as a highly efficacious therapeutic modality for malignant tumors owing to its non-invasive property and minimal adverse effects....
Acid-triggered controlled release and fluorescence-switchable phthalocyanine nanoassemblies combined with O-economizer for tumor imaging and collaborative photodynamic antitumor therapy.
Photodynamic therapy (PDT) has emerged as a highly efficacious therapeutic modality for malignant tumors owing to its non-invasive property and minimal adverse effects. However, the pervasive hypoxic microenvironment within tumors significantly compromises the efficacy of oxygen-dependent PDT, posing a formidable challenge to the advancement of high-efficiency PDT. Here, we developed a nanostructured photosensitizer (PS) assembled by cationic and anionic zinc phthalocyanines to load oxygen-throttling drug atovaquone (ATO), which was subsequently coated with polydopamine to obtain the final product ATO/ZnPc-CA@DA. ATO/ZnPc-CA@DA exhibited excellent stability, particularly in the blood milieu. Interestingly, the acidic microenvironment can trigger drug release from ATO/ZnPc-CA@DA, leading to a significant enhancement in fluorescence and an augmented generation of reactive oxygen species (ROS). ATO/ZnPc-CA@DA can induce synergistic cytotoxicity of PS and ATO, and significantly enhance the killing ability against tumor cells under hypoxic conditions. The mechanism underlying cytotoxicity of ATO/ZnPc-CA@DA was demonstrated to be associated with augmented cell apoptosis, disruption of mitochondrial membrane potential, diminished ATP production, heightened intracellular ROS generation, and reduced intracellular oxygen consumption. The animal experiments indicated that ATO/ZnPc-CA@DA possessed enhanced tumor targeting capability, along with a reduction in PS distribution within normal organs. Furthermore, ATO/ZnPc-CA@DA exhibited enhanced inhibitory effect on tumor growth and caused aggravated damage to tumor tissue. The construction strategy of nanostructured PS and the synergistic antitumor principle of combined oxygen-throttling drugs can be applied to other PSs, thereby advancing the development of photodynamic antitumor therapy and promoting the clinical translation.
Topics: Animals; Photochemotherapy; Reactive Oxygen Species; Delayed-Action Preparations; Cell Line, Tumor; Fluorescence; Photosensitizing Agents; Isoindoles; Oxygen; Organometallic Compounds; Nanoparticles
PubMed: 37995641
DOI: 10.1016/j.bioorg.2023.106986 -
Ticks and Tick-borne Diseases Jan 2024Canine babesiosis is an important protozoan tick-borne disease associated with anemia and thrombocytopenia and caused by several different Babesia spp. Babesia negevi...
Canine babesiosis is an important protozoan tick-borne disease associated with anemia and thrombocytopenia and caused by several different Babesia spp. Babesia negevi was first reported to infect dogs in the Middle East in 2020. This study describes the presentation, clinical signs, parasitemia levels quantified by molecular techniques, laboratory findings and treatment of dogs infected with B. negevi following the first description of this species. Clinical findings in the infected dogs, a 3-year old female and two 8-week old male and female pups, included extreme lethargy and pale mucous membranes, anemia and thrombocytopenia found in all three animals. Fever was present in the older female and icterus in the female pup. Babesia parasites resembling B. negevi were detected by microscopy of blood smears from the dogs. PCR of blood targeting the 18S rRNA and cox1 genes confirmed that babesiosis was caused by B. negevi and PCR targeting the Borrelia flagellin gene indicated co-infection with Borrelia persica in two dogs. Treatment of the dogs with imidocarb dipropionate resulted in clinical improvement and initial decrease in the B. negevi parasite load as detected by quantitative PCR in two dogs, however the female pup continued to deteriorate and died. The parasite load in the 3-year old female decreased from 43,451 parasites/µl blood pre-imidocarb dipropionate treatment to 803 parasites/µl within two weeks. In the surviving pup, it decreased from 3,293,538 parasites/µl pre-treatment to 20,092 parasites/µl after two weeks. Babesia negevi DNA was still recovered from blood samples by PCR despite repeated treatment with imidocarb dipropionate one-month post-treatment in the surviving pup and up to seven months post-treatment in the 3-year old female. Only treatment with atovaquone and azithromycin for ten days eliminated B. negevi in both dogs as confirmed by negative PCR two weeks later. In conclusion, treatment with imidocarb dipropionate was helpful for recovery from clinical disease but did not facilitate parasite elimination, and it is therefore recommended to treat canine B. negevi infection with the combination of atovaquone and azithromycin.
Topics: Dogs; Animals; Male; Female; Babesiosis; Atovaquone; Antiprotozoal Agents; Azithromycin; Babesia; Thrombocytopenia; Anemia; Dog Diseases
PubMed: 37989015
DOI: 10.1016/j.ttbdis.2023.102282 -
Clinical and Translational Radiation... Jan 2024Neoadjuvant radiotherapy is successfully used in rectal cancer to improve overall survival. However, treatment response is both unpredictable and variable. There is...
INTRODUCTION
Neoadjuvant radiotherapy is successfully used in rectal cancer to improve overall survival. However, treatment response is both unpredictable and variable. There is strong evidence to show that the phenomenon of tumour hypoxia is associated with radioresistance, however the mechanism(s) behind this are poorly understood. Consequently, there have only been a small number of studies evaluating methods targeting hypoxia-induced radioresistance. The purpose of this systematic review is to evaluate the potential effectiveness of targeting hypoxia-induced radioresistance in rectal cancer and provide recommendations for future research in this area.
METHODS
A comprehensive literature search was performed following the PRISMA guidelines. This study was registered on the Prospero database (CRD42023441983).
RESULTS
Eight articles met the inclusion criteria. All studies identified were or studies, there were no clinical trials. Of the 8 studies identified, 5 assessed the efficacy of drugs which directly or indirectly targeted hypoxia and three that identified potential targets. There was conflicting evidence for the use of metformin to overcome hypoxia induced radioresistance. Vorinostat, atovaquone, and evofosfamide showed promising preclinical evidence that they can overcome hypoxia-induced radioresistance.
DISCUSSION
The importance of investigating hypoxia-induced radioresistance in rectal cancer is crucial. However, to date, only a small number of preclinical studies exist evaluating this phenomenon. This systematic review highlights the importance of further research to fully understand the mechanism behind this radioresistance. There are promising targets identified in this systematic review however, substantially more pre-clinical and clinical research as a priority for future research is needed.
PubMed: 37961749
DOI: 10.1016/j.ctro.2023.100695 -
Acta Tropica Jan 2024Diminazene aceturate (DA), imidocarb dipropionate (ID), atovaquone (ATO), azithromycin (AZI), clindamycin, and quinine have been used to treat animal and human...
Diminazene aceturate (DA), imidocarb dipropionate (ID), atovaquone (ATO), azithromycin (AZI), clindamycin, and quinine have been used to treat animal and human babesiosis for many years, despite their negative effects and rising indications of resistance. Thus, finding anti-babesial compounds that can either treat the infection or lower the dose of drugs given has been a primary objective. Quinazolines are one of the most important nitrogen heterocycles, with a wide range of pharmacological activities including analgesic, anti-inflammatory, sedative-hypnotic, anti-histaminic, anti-cancer, and anti-protozoan properties. The present study investigated the anti-babesial activities of twenty 6,7-dimethoxyquinazoline-2,4-diamines on Babesia spp. One candidate, 6,7-dimethoxy-N-ethylisopropyl-N-ethyl(pyridin-4-yl)quinazoline-2,4-diamine (SHG02), showed potent inhibition on Babesia gibsoni in vitro, as well as on B. microti and B. rodhaini in mice. Our findings indicate that the candidate compound SHG02 is promising for further development of anti-babesial drugs and provides a new structure to be explored for developing anti-Babesia therapeutics.
Topics: Dogs; Animals; Humans; Mice; Babesia; Dog Diseases; Babesiosis; Atovaquone; Azithromycin; Antiprotozoal Agents
PubMed: 37952866
DOI: 10.1016/j.actatropica.2023.107069 -
BMC Cancer Nov 2023Colorectal cancer is a common malignant tumour. Invasive growth and distant metastasis are the main characteristics of its malignant biological behaviour, and they are...
BACKGROUND
Colorectal cancer is a common malignant tumour. Invasive growth and distant metastasis are the main characteristics of its malignant biological behaviour, and they are also the primary factors leading to death in colon cancer patients. Atovaquone is an antimalarial drug, and its anticancer effect has recently been demonstrated in several cancer models in vitro and in vivo, but it has not been examined in the treatment of colorectal cancer.
METHODS
To elucidate the effect of atovaquone on colorectal cancer. We used RNA transcriptome sequencing, RT‒PCR and Western blot experiments to examine the expression of NF-κB (p-P65), EMT-related proteins and related inflammatory factors (IL1B, IL6, CCL20, CCL2, CXCL8, CXCL6, IL6ST, FAS, IL10 and IL1A). The effect of atovaquone on colorectal cancer metastasis was validated using an animal model of lung metastases. We further used transcriptome sequencing, the GCBI bioinformatics database and the STRING database to predict relevant target proteins. Furthermore, pathological sections were collected from relevant cases for immunohistochemical verification.
RESULTS
This study showed that atovaquone could inhibit colorectal cancer metastasis and invasion in vivo and in vitro, inhibit the expression of E-cadherin protein, and promote the protein expression of N-cadherin, vimentin, ZEB1, Snail and Slug. Atovaquone could inhibit EMT by inhibiting NF-κB (p-P65) and related inflammatory factors. Further bioinformatics analysis and verification showed that PDGFRβ was one of the targets of atovaquone.
CONCLUSION
In summary, atovaquone can inhibit the expression of NF-κB (p-P65) and related inflammatory factors by inhibiting the protein expression of p-PDGFRβ, thereby inhibiting colorectal cancer metastasis. Atovaquone may be a promising drug for the treatment of colorectal cancer metastasis.
Topics: Animals; Humans; NF-kappa B; Atovaquone; Cell Line, Tumor; Signal Transduction; Colorectal Neoplasms; Epithelial-Mesenchymal Transition; Cell Movement
PubMed: 37932661
DOI: 10.1186/s12885-023-11585-9 -
Cancer Communications (London, England) Mar 2024
Topics: Humans; Atovaquone; Tumor Microenvironment; Energy Metabolism; Mitochondria; Lung Neoplasms
PubMed: 37930151
DOI: 10.1002/cac2.12500 -
Case Reports in Infectious Diseases 2023
PubMed: 37908307
DOI: 10.1155/2023/9793264 -
Chemical Science Oct 2023Photodynamic therapy (PDT) has emerged as an invasive and promising antitumour treatment, however, the hypoxia in deep tumour tissues and the poor water-solubility of...
Photodynamic therapy (PDT) has emerged as an invasive and promising antitumour treatment, however, the hypoxia in deep tumour tissues and the poor water-solubility of photosensitizers as bottlenecks greatly hinder PDT efficiency. Herein, a tumour microenvironment (TME) activated supramolecular nanoplatform consisting of the pillar[5]arene-based amphiphilic polymer POPD, the phototherapeutic agent Cy7-CN, respiratory medication atovaquone (ATO) and chemotherapeutic drug pyridinyl camptothecin (CPT-Py) was constructed for imaging-guided hypoxia-ameliorated phototherapies. Owing to host-guest interaction, the photochemical and photophysical properties of cyanine were improved exceedingly due to the suppression of π-π stacking. Triggered by the acidic microenvironment in tumour sites, the supramolecular nanoplatform would dissociate and release CPT-Py and ATO which inhibits mitochondria-associated oxidative phosphorylation (OXPHOS) and encourages more oxygen to be used in enhanced PDT. and studies verified that the rational combination of ATO-enhanced PDT and PTT overcame the disadvantages of single phototherapy and formed mutual promotion, and simultaneously sensitized chemotherapeutic drugs, which resulted in high tumour inhibition. It is hoped that the supramolecular nanoplatform could shed light on the development of phototherapeutic agents.
PubMed: 37886080
DOI: 10.1039/d3sc03797e -
MBio Oct 2023parasites rely on a functional electron transport chain (ETC) within their mitochondrion for proliferation, and compounds targeting mitochondrial functions are...
parasites rely on a functional electron transport chain (ETC) within their mitochondrion for proliferation, and compounds targeting mitochondrial functions are validated antimalarials. Here, we localize patatin-like phospholipase 2 (PNPLA2, PF3D7_1358000) to the mitochondrion and reveal that disruption of the PNPLA2 gene impairs asexual replication. PNPLA2-null parasites are hypersensitive to proguanil and inhibitors of the mitochondrial ETC, including atovaquone. In addition, PNPLA2-deficient parasites show reduced mitochondrial respiration and reduced mitochondrial membrane potential, indicating that disruption of PNPLA2 leads to a defect in the parasite ETC. Lipidomic analysis of the mitochondrial phospholipid cardiolipin (CL) reveals that loss of PNPLA2 is associated with a moderate shift toward shorter-chained and more saturated CL species, implying a contribution of PNPLA2 to CL remodeling. PNPLA2-deficient parasites display profound defects in gametocytogenesis, underlining the importance of a functional mitochondrial ETC during both the asexual and sexual development of the parasite. IMPORTANCE For their proliferation within red blood cells, malaria parasites depend on a functional electron transport chain (ETC) within their mitochondrion, which is the target of several antimalarial drugs. Here, we have used gene disruption to identify a patatin-like phospholipase, PNPLA2, as important for parasite replication and mitochondrial function in . Parasites lacking PNPLA2 show defects in their ETC and become hypersensitive to mitochondrion-targeting drugs. Furthermore, PNPLA2-deficient parasites show differences in the composition of their cardiolipins, a unique class of phospholipids with key roles in mitochondrial functions. Finally, we demonstrate that parasites devoid of PNPLA2 have a defect in gametocyte maturation, underlining the importance of a functional ETC for parasite transmission to the mosquito vector.
PubMed: 37882543
DOI: 10.1128/mbio.01718-23 -
ACS Nano Nov 2023Therapeutic tumor vaccines, which use tumor antigens to stimulate a cancer patient's immune system to eventually kill the tumor tissues, have emerged as one of the most...
Therapeutic tumor vaccines, which use tumor antigens to stimulate a cancer patient's immune system to eventually kill the tumor tissues, have emerged as one of the most attractive strategies in anticancer research. Especially, exploring vaccines has become a potential field in cancer immunotherapy. However, due to the hypoxic tumor microenvironment, the generation of tumor antigens is always mild and not sufficient. Hence, in this study, we designed a closed-loop mitochondrial oxygen-economizer (TPCA) to induce enhanced phototherapy-driven vaccines. The O-economizer was developed by the integration of the photosensitizer CyI and the mitochondrial inhibitor atovaquone into the PAMAM dendrimer. and studies showed that TPCA could enter the mitochondria through (3-propylcarboxyl) triphenylphosphine bromide (TPP) and effectively restrict the respiration of tumor cells to reduce tumor hypoxia, thus providing continuous oxygen for enhanced iodinated cyanine dye mediated photodynamic therapy, which could further induce vaccines for ablating the primary tumor directly and inhibiting the tumor metastasis and recurrence. Furthermore, the antitumor mechanism revealed that O-economizer-based oxygen-boosted PDT elicited immunogenic cancer cell death with enhanced exposure and release of DAMPs and altered the immunosuppressive tumor microenvironment with increased recruitment of T cells in tumors, thereby inducing vaccines and provoking the systematic antitumor responses against CT26 tumors. This study will provide innovative approaches for local, abscopal, and metastatic tumor treatment.
Topics: Humans; Photochemotherapy; Oxygen; Phototherapy; Hypoxia; Photosensitizing Agents; Cancer Vaccines; Antigens, Neoplasm; Cell Line, Tumor; Tumor Microenvironment; Nanoparticles
PubMed: 37877944
DOI: 10.1021/acsnano.3c05034