Evaluation of tumor growth remission in a murine model for subcutaneous solid tumors - Benefits of associating the antitumor agent crotamine with mesoporous nanosilica particles to achieve improved dosing frequency and efficacy.

Crotamine is a highly cationic polypeptide first isolated from South American rattlesnake venom, which exhibits affinity for acidic lysosomal vesicles and proliferating cells. This cationic nature is pivotal for its in vitro cytotoxicity and in vivo anticancer actions. This study aimed to enhance the antitumor efficacy of crotamine by associating it with the mesoporous SBA-15 silica, known for its controlled release of various chemical agents, including large proteins. This association aimed to mitigate the toxic effects while amplifying the pharmacological potency of several compounds. Comprehensive characterization, including transmission electron microscopy (TEM), dynamic light scattering (DLS), and zeta potential analysis, confirmed the successful association of crotamine with the non-toxic SBA-15 nanoparticles. The TEM imaging revealed nanoparticles with a nearly spherical shape and variations in uniformity upon crotamine association. Furthermore, DLS showed a narrow unimodal size distribution, emphasizing the formation of small aggregates. Zeta potential measurements indicated a distinct shift from negative to positive values upon crotamine association, underscoring its effective adsorption onto SBA-15. Intraperitoneal or oral administration of crotamine:SBA-15 in a murine melanoma model suggested the potential to reduce the frequency of crotamine doses without compromising efficacy. Interestingly, while the oral route enhanced the antitumor efficacy of crotamine, pH-dependent release from SBA-15 was observed. Thus, associating crotamine with SBA-15 could reduce the overall required dose to inhibit solid tumor growth, bolstering the prospect of crotamine as a potent anticancer agent.

Evaluation of tumor growth remission in a murine model for subcutaneous solid tumors, benefits of associating the antitumor agent crotamine with mesoporous nanosilica particles to achieve improved dosing frequency and efficacy

Crotamine is a highly cationic polypeptide first isolated from South American rattlesnake venom, which exhibits affinity for acidic lysosomal vesicles and proliferating cells. This cationic nature is pivotal for its in vitro cytotoxicity and in vivo anticancer actions. This study aimed to enhance the antitumor efficacy of crotamine by associating it with the mesoporous SBA-15 silica, known for its controlled release of various chemical agents, including large proteins. This association aimed to mitigate the toxic effects while amplifying the pharmacological potency of several compounds. Comprehensive characterization, including transmission electron microscopy (TEM), dynamic light scattering (DLS), and zeta potential analysis, confirmed the successful association of crotamine with the non-toxic SBA-15 nanoparticles. The TEM imaging revealed nanoparticles with a nearly spherical shape and variations in uniformity upon crotamine association. Furthermore, DLS showed a narrow unimodal size distribution, emphasizing the formation of small aggregates. Zeta potential measurements indicated a distinct shift from negative to positive values upon crotamine association, underscoring its effective adsorption onto SBA-15. Intraperitoneal or oral administration of crotamine:SBA-15 in a murine melanoma model suggested the potential to reduce the frequency of crotamine doses without compromising efficacy. Interestingly, while the oral route enhanced the antitumor efficacy of crotamine, pH-dependent release from SBA-15 was observed. Thus, associating crotamine with SBA-15 could reduce the overall required dose to inhibit solid tumor growth, bolstering the prospect of crotamine as a potent anticancer agent.

Evaluation of tumor growth remission in a murine model for subcutaneous solid tumors, benefits of associating the antitumor agent crotamine with mesoporous nanosilica particles to achieve improved dosing frequency and efficacy

Crotamine is a highly cationic polypeptide first isolated from South American rattlesnake venom, which exhibits affinity for acidic lysosomal vesicles and proliferating cells. This cationic nature is pivotal for its in vitro cytotoxicity and in vivo anticancer actions. This study aimed to enhance the antitumor efficacy of crotamine by associating it with the mesoporous SBA-15 silica, known for its controlled release of various chemical agents, including large proteins. This association aimed to mitigate the toxic effects while amplifying the pharmacological potency of several compounds. Comprehensive characterization, including transmission electron microscopy (TEM), dynamic light scattering (DLS), and zeta potential analysis, confirmed the successful association of crotamine with the non-toxic SBA-15 nanoparticles. The TEM imaging revealed nanoparticles with a nearly spherical shape and variations in uniformity upon crotamine association. Furthermore, DLS showed a narrow unimodal size distribution, emphasizing the formation of small aggregates. Zeta potential measurements indicated a distinct shift from negative to positive values upon crotamine association, underscoring its effective adsorption onto SBA-15. Intraperitoneal or oral administration of crotamine:SBA-15 in a murine melanoma model suggested the potential to reduce the frequency of crotamine doses without compromising efficacy. Interestingly, while the oral route enhanced the antitumor efficacy of crotamine, pH-dependent release from SBA-15 was observed. Thus, associating crotamine with SBA-15 could reduce the overall required dose to inhibit solid tumor growth, bolstering the prospect of crotamine as a potent anticancer agent.

Radiobiological and Treatment-Related Aspects of Spatially Fractionated Radiotherapy.

The continuously evolving field of radiotherapy aims to devise and implement techniques that allow for greater tumour control and better sparing of critical organs. Investigations into the complexity of tumour radiobiology confirmed the high heterogeneity of tumours as being responsible for the often poor treatment outcome. Hypoxic subvolumes, a subpopulation of cancer stem cells, as well as the inherent or acquired radioresistance define tumour aggressiveness and metastatic potential, which remain a therapeutic challenge. Non-conventional irradiation techniques, such as spatially fractionated radiotherapy, have been developed to tackle some of these challenges and to offer a high therapeutic index when treating radioresistant tumours. The goal of this article was to highlight the current knowledge on the molecular and radiobiological mechanisms behind spatially fractionated radiotherapy and to present the up-to-date preclinical and clinical evidence towards the therapeutic potential of this technique involving both photon and proton beams.

Characteristic differences in radiation-induced DNA damage response in human papillomavirus-negative and human papillomavirus-positive head and neck cancers with accumulation of fractional radiation dose.

BACKGROUND: Superior treatment responses by patients with human papillomavirus (HPV) positive head and neck squamous cell carcinoma (HNSCC), compared to patients with HNSCC from other causes, drive biomarker research to optimize treatment. Most HNSCC patients receive radiation therapy delivered as a fractionated course. Changing HPV status in HNSCC from a positive prognostic marker to a predictive one requires biomarkers that capture cellular radiation response to cumulative dose. METHODS: Nuclear enlargement, γH2AX expression and micronuclei count, were studied in six HNSCC cell lines after 4 Gy fractionated X-irradiation. RESULTS: All HNSCC cell lines displayed altered cellular responses, indicating increasing inability to repair radiation damage with subsequent radiation fractions. Increases in nuclear area were significantly greater among HPV positive cell lines (207% and 67% for the HPV positive and HPV negative groups, respectively). CONCLUSIONS: A different character of DNA repair dysfunction in the HPV positive group suggests greater chromosomal translocation with accumulated radiation dose.

Author Correction: Cobrotoxin could be an effective therapeutic for COVID-19.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Intrinsic Radiosensitivity Is Not the Determining Factor in Treatment Response Differences between HPV Negative and HPV Positive Head and Neck Cancers.

Head and neck squamous cell carcinomas (HNSCC) resulting from human papillomavirus (HPV) are increasing in incidence but demonstrate significantly better treatment response than HNSCC from other causes such as tobacco and alcohol. This study sought to identify differences in HNSCC, intrinsic to HPV status, in their response to radiation dose. Previously unexamined changes in radio-responsiveness following fractionated X-ray irradiation were compared between HPV positive and negative statuses of HNSCC. Six HNSCC cell lines, 3 of each HPV status, were investigated for radiosensitivity by clonogenic assay and modelled by response as a function of dose. Generational cultures of each cell line were developed to follow changes in radiosensitivity after repeated irradiations simulating fractionated radiation therapy. As a group, the HPV positive cell lines were more radiosensitive, but with changes following repeated fractions of dose, and modelling of response as a function of dose, both statuses displayed large radiobiological heterogeneity. These findings challenge current radiobiological assumptions of head and neck cancers as early responding tissue to radiation and may go some way in explaining difficulties reaching consensus in stratification of treatment by HPV status. Consequently, results from this study do not support stratifying radiation therapy by HPV status.

Influence of the human papillomavirus on the radio-responsiveness of cancer stem cells in head and neck cancers.

A growing proportion of head and neck cancers (HNC) result from HPV infection. Between HNC aetiological groups (HPV positive and HPV negative) clinical evidence demonstrates significantly better treatment response among HPV positive cancers. Cancer stem cells (CSCs) are identified in HNC tumour populations as agents of treatment resistance and a target for tumour control. This study examines dynamic responses in populations of a CSC phenotype in HNC cell lines following X-irradiation at therapeutic levels, and comparing between HPV statuses. Variations in CSC density between HPV groups showed no correlation with better clinical outcomes seen in the HPV positive status. CSC populations in HPV positive cell lines ranged from 1.9 to 4.8%, and 2.6 to 9.9% for HPV negative. Following 4 Gy X- irradiation however, HPV negative cell lines demonstrated more frequent and significantly greater escalation in CSC proportions, being 3-fold that of the HPV positive group at 72 hours post irradiation. CSC proportions of tumour populations are not fixed but subject to change in response to radiation at therapeutic dose levels. These findings imply a potential effect of aetiology on radio-responsiveness in CSCs, illustrating that clonogen treatment response may be more informative of therapy outcomes than inherent population density alone.

Diversity of cancer stem cells in head and neck carcinomas: The role of HPV in cancer stem cell heterogeneity, plasticity and treatment response.

Head and neck squamous cell carcinomas (HNSCC) resulting from oncogenic transformations following human papillomavirus (HPV) infection consistently demonstrate better treatment outcomes than HNSCC from other aetiologies. Squamous cell carcinoma of the oropharynx (OPSCC) shows the highest prevalence of HPV involvement at around 70-80%. While strongly prognostic, HPV status alone is not sufficient to predict therapy response or any potential dose de-escalation. Cancer stem cell (CSC) populations within these tumour types represent the most therapy-resistant cells and are the source of recurrence and metastases, setting a benchmark for tumour control. This review examines clinical and preclinical evidence of differences in response to treatment by the HPV statuses of HNSCC and the role played by CSCs in treatment resistance and their repopulation from non-CSCs. Evidence was collated from literature searches of PubMed, Scopus and Ovid for differential treatment response by HPV status and contribution by critical biomarkers including CSC fractions and chemo-radiosensitivity. While HPV and CSC are yet to fulfil promise as biomarkers of treatment response, understanding how HPV positive and negative aetiologies affect CSC response to treatment and tumour plasticity will facilitate their use for greater treatment individualisation.

Design and fabrication of prototype piezoelectric adjustable X-ray mirrors.

Lynx, a next generation X-ray observatory concept currently under study, requires lightweight, high spatial resolution X-ray mirrors. Here we detail the development and fabrication of one of the candidate technologies for Lynx, piezoelectric adjustable X-ray optics. These X-ray mirrors are thin glass shell mirrors with Cr/Ir X-ray reflective coatings on the mirror side and piezoelectric thin film actuators on the actuator side. Magnetron sputtering was used to deposit metal electrodes and metal-oxide piezoelectric layers. The piezoelectric (Pb0.995(Zr0.52Ti0.48)0.99Nb0.01O3) was divided into 112 independent piezoelectric actuators, with 100% yield achieved. We discuss the fabrication procedure, residual thermal stresses and tuning of the Cr/Ir coating stress for the purposes of stress balancing.

The Promise of Novel Biomarkers for Head and Neck Cancer from an Imaging Perspective.

It is an agreed fact that overall survival among head and neck cancer patients has increased over the last decade. Several factors however, are still held responsible for treatment failure requiring more in-depth evaluation. Among these, hypoxia and proliferation-specific parameters are the main culprits, along with the more recently researched cancer stem cells. This paper aims to present the latest developments in the field of biomarkers for hypoxia, stemness and tumour proliferation, from an imaging perspective that includes both Positron Emission Tomography (PET) and Single Photon Emission Computed Tomography (SPECT) as well as functional magnetic resonance imaging (MRI). Quantitative imaging of biomarkers is a prerequisite for accurate treatment response assessment, bringing us closer to the highly needed personalised therapy.

Experimental investigation of radiobiology in head and neck cancer cell lines as a function of HPV status, by MTT assay.

Head and neck cancers (HNCs) are aggressive epithelial tumours frequently treated using radiation. HNC biology shows distinctions dependent on the oncologic involvement of the human papilloma virus (HPV). Clinically, HPV positive HNCs respond better to radiotherapy but few in vitro data demonstrate radiobiological differences explaining differences in clinical outcomes. This pilot study examined radiobiological responses to irradiation and subsequent regeneration in two HNC cell lines (HPV positive and negative). A novel approach was taken to develop generational cultures of HNC cell lines, UM-SCC-1 (HPV negative) and UM-SCC-47 (HPV positive). MTT assays were used to determine surviving metabolic activity as a function of dose following 6 MV X-ray irradiation. Parallel cultures surviving 4 Gy irradiation (not analysed) were re-cultured and passaged to develop subsequent generations which were re-irradiated and analysed for generational change in radiation response. Second and 3rd generations of UM-SCC-1 showed decreasing metabolic activity with dose but little difference was evident in surviving fractions between these generations. Significantly lower metabolic activity in the 3rd generation at <6 Gy, compared to the 2nd generation, showed UM-SCC-47 becoming progressively more radiosensitive. HPV positive UM-SCC-47 showed generational progression in radiosensitisation not seen in the HPV negative UM-SCC-1.

An orally available, brain-penetrant CAMKK2 inhibitor reduces food intake in rodent model.

Hypothalamic CAMKK2 represents a potential mechanism for chemically affecting satiety and promoting weight loss in clinically obese patients. Single-digit nanomolar inhibitors of CAMKK2 were identified in three related ATP-competitive series. Limited optimization of kinase selectivity, solubility, and pharmacokinetic properties were undertaken on all three series, as SAR was often transferrable. Ultimately, a 2,4-diaryl 7-azaindole was optimized to afford a tool molecule that potently inhibits AMPK phosphorylation in a hypothalamus-derived cell line, is orally bioavailable, and crosses the blood-brain barrier. When dosed orally in rodents, compound 4 t limited ghrelin-induced food intake.

Blood Lead Toxicity Analysis of Multipurpose Canines and Military Working Dogs.

Special Operations Forces and their accompanying tactical multipurpose canines (MPCs) who are involved in repeated live-fire exercises and military operations have the potential for increased blood lead levels and toxicity due to aerosolized and environmental lead debris. Clinical lead-toxicity symptoms can mimic other medical disorders, rendering accurate diagnosis more challenging. The objective of this study was to examine baseline lead levels of MPCs exposed to indoor firing ranges compared with those of nontactical military working dogs (MWDs) with limited or no exposure to the same environment. In the second part of the study, results of a commercially available, human-blood lead testing system were compared with those of a benchtop inductively coupled plasma-mass spectrometry (ICP-MS) analysis technique. Blood samples from 18 MPCs were tested during routine clinical blood draws, and six samples from a canine group with limited exposure to environmental lead (nontactical MWDs) were tested for comparison. There was a high correlation between results of the commercial blood-testing system compared with ICP-MS when blood lead levels were higher than 4.0µg/dL. Both testing methods recorded higher blood lead levels in the MPC blood samples than in those of the nontactical MWDs, although none of the MPC samples tested contained lead levels approaching those at which symptoms of lead toxicity have previously been reported in animals (i.e., 35µg/dL).

In vitro investigation of head and neck cancer stem cell proportions and their changes following X-ray irradiation as a function of HPV status.

INTRODUCTION: Some head and neck squamous cell carcinomas (HNSCC) have a distinct aetiology, which depends on the presence of oncogenic human papilloma virus (HPV). Also, HNSCC contains cancer stem cells (CSCs) that have greater radioresistance and capacity to change replication dynamics in response to irradiation compared to non-clonogenic cells. Since there is limited data on CSCs in HNSCC as a function of HPV status, better understanding of their radiobiology may enable improved treatment outcome. METHODS: Baseline and post-irradiation changes in CSC proportions were investigated by flow cytometry in a HPV-negative (UM-SCC-1) and a HPV-positive (UM-SCC-47) HNSCC cell line, using fluorescent staining with CD44/ALDH markers. CSC proportions in both irradiated and unirradiated cultures were compared for the two cell lines at various times post-irradiation. To assess repopulation of CSCs, untreated cultures were depleted of CD44+/ALDH+ cells and re-cultured for 3 weeks before flow cytometry analysis. RESULTS: CSC proportions in untreated cell lines were 0.57% (UM-SCC-1) and 2.87% (UM-SCC-47). Untreated cell lines depleted of CD44+/ALDH+ repopulated this phenotype to a mean of 0.15% (UM-SCC-1) and 6.76% (UM-SCC-47). All UM-SCC-47 generations showed elevated CSC proportions after irradiation, with the most significant increase at 2 days post-irradiation. The highest elevation in UM-SCC-1 CSCs was observed at 1 day post-irradiation in the 2nd generation and at 3 days after irradiation in the 3rd generation. When measured after 10 days, only the 3rd generation of UM-SCC-1 showed elevated CSCs. CONCLUSIONS: CSC proportions in both cell lines were elevated after exposure and varied with time post irradiation. UM-SCC-47 displayed significant plasticity in repopulating the CSC phenotype in depleted cultures, which was not seen in UM-SCC-1.

Current understanding of cancer stem cells: Review of their radiobiology and role in head and neck cancers.

Evidence of cancer cells that bear attributes analogous to those of normal stem cells has developed a hierarchical model of cancer's architecture and progression. This subset of cancer stem cells (CSCs) drives the progression and therapy resistance of cancers. Research to identify the phenotypes of these CSCs presents evidence of a subpopulation that is more resistant to therapy and may proliferate in response. Literature shows that CSCs typically represent around 1%-10% of cell populations in head and neck cancer but this proportion may increase in response to a therapeutic radiation dose. This is shown to be not just as a result of preferential killing, but also their capacity to alter divisional dynamics and enlist the support of a complicit microenvironment in therapy resistance and proliferation. The CSCs represent the apex of a hierarchy in the heterogeneity of cancer cells and may be seen as the agents of treatment failure, metastasis, and tumor recurrence, the principal cause of mortality in head and neck cancers. Greater than 90% of head and neck cancers are squamous cell carcinomas (HNSCCs), and among these an increasing incidence of the involvement of the human papillomavirus (HPV) is reported. Chemoradiotherapy along with surgical resection are the interventions of choice for control and cure of HNSCC, but given CSCs therapy resistance and proliferative responses to radiation, the identification and understanding of the radiobiology of this subpopulation is critical to their targeted elimination. This article reviews the current evidence on CSC generally and in HNSCC specifically to identify their phenotype, evaluate their responses to radiotherapy, and evaluate the defensive mechanisms used to resist therapeutic control.

Innovative design for a phase 1 trial with intra-patient dose escalation: The Crotoxin study.

INTRODUCTION: Crotoxin has a broad antitumor activity but has shown frequent neurotoxic toxicity. To induce tolerance and limit this toxicity, we propose a new design with intra-patient dose escalation. METHODS: A new Dose Limiting Toxicity definition was used. The concept of Target Ceiling Dose was introduced. RESULTS: Dose Limiting Toxicity was the inability to dose escalate twice. Target Ceiling Dose was the highest planned dose to be administered to a patient and could change for patients along time. Recommended Dose was defined similarly as in a (3 + 3) conventional design. CONCLUSION: This innovant design was used and the clinical trial is now closed for inclusions. Results will be presented later.

Decoupling Activation of Heme Biosynthesis from Anaerobic Toxicity in a Molecule Active in Staphylococcus aureus.

Small molecules active in the pathogenic bacterium Staphylococcus aureus are valuable tools for the study of its basic biology and pathogenesis, and many molecules may provide leads for novel therapeutics. We have previously reported a small molecule, 1, which activates endogenous heme biosynthesis in S. aureus, leading to an accumulation of intracellular heme. In addition to this novel activity, 1 also exhibits toxicity towards S. aureus growing under fermentative conditions. To determine if these activities are linked and establish what features of the molecule are required for activity, we synthesized a library of analogs around the structure of 1 and screened them for activation of heme biosynthesis and anaerobic toxicity to investigate structure-activity relationships. The results of this analysis suggest that these activities are not linked. Furthermore, we have identified the structural features that promote each activity and have established two classes of molecules: activators of heme biosynthesis and inhibitors of anaerobic growth. These molecules will serve as useful probes for their respective activities without concern for the off target effects of the parent compound.

Sputter deposition of PZT piezoelectric films on thin glass substrates for adjustable x-ray optics.

Piezoelectric PbZr(0.52)Ti(0.48)O(3) (PZT) thin films deposited on thin glass substrates have been proposed for adjustable optics in future x-ray telescopes. The light weight of these x-ray optics enables large collecting areas, while the capability to correct mirror figure errors with the PZT thin film will allow much higher imaging resolution than possible with conventional lightweight optics. However, the low strain temperature and flexible nature of the thin glass complicate the use of chemical-solution deposition due to warping of the substrate at typical crystallization temperatures for the PZT. RF magnetron sputtering enabled preparation of PZT films with thicknesses up to 3 µm on Schott D263 glass substrates with much less deformation. X-ray diffraction analysis indicated that the films crystallized with the perovskite phase and showed no indication of secondary phases. Films with 1 cm(2) electrodes exhibited relative permittivity values near 1100 and loss tangents below 0.05. In addition, the remanent polarization was 26 µC/cm(2) with coercive fields of 33 kV/cm. The transverse piezoelectric coefficient was as high as -6.1±0.6 C/m(2). To assess influence functions for the x-ray optics application, the piezoelectrically induced deflection of individual cells was measured and compared with finite-element-analysis calculations. The good agreement between the results suggests that actuation of PZT thin films can control mirror figure errors to a precision of about 5 nm, allowing sub-arcsecond imaging.