Rabbit Tumor Research Articles

Oncolytic mineralized bacteria as potent locally administered immunotherapeutics.

Oncolytic bacteria can trigger innate immune activity. However, the antitumour efficacy of inactivated bacteria is poor, and attenuated live bacteria pose substantial safety risks. Here we show that intratumourally injected paraformaldehyde-fixed bacteria coated with manganese dioxide potently activate innate immune activity, modulate the immunosuppressive tumour microenvironment and trigger tumour-specific immune responses and abscopal antitumour responses. A single intratumoural administration of mineralized Salmonella typhimurium suppressed the growth of multiple types of subcutaneous and orthotopic tumours in mice, rabbits and tree shrews and protected the cured animals against tumour rechallenge. We also show that mineralized bacteria can be administered via arterial embolization to treat orthotopic liver cancer in rabbits. Our findings support the further translational testing of oncolytic mineralized bacteria as potent and safe antitumour immunotherapeutics.

Nanoparticle mediated photodynamic therapy as a method to ablate oral cavity squamous cell carcinoma in preclinical models.

Photodynamic therapy (PDT) is a tissue ablation technique able to selectively target tumour cells by activating the cytotoxicity of photosensitiser dyes with light. PDT is nonsurgical and tissue sparing, two advantages for treatments in anatomically complex disease sites such as the oral cavity. We have previously developed PORPHYSOME (PS) nanoparticles assembled from chlorin photosensitiser-containing building blocks (~94,000 photosensitisers per particle) and capable of potent PDT. In this study, we demonstrate the selective uptake and curative tumour ablation of PS-enabled PDT in three preclinical models of oral cavity squamous cell carcinoma: biologically relevant subcutaneous Cal-33 (cell-line) and MOC22 (syngeneic) mouse models, and an anatomically relevant orthotopic VX-2 rabbit model. Tumours selectively uptake PS (10 mg/kg, IV) with 6~40-fold greater concentration versus muscle 24 hours post-injection. Single PS-PDT treatment (100 J/cm2, 100 mW/cm2) of Cal-33 tumours yielded significant apoptosis in 65.7% of tumour cells. Survival studies following PS-PDT treatments demonstrated 90% (36/40) overall response rate across all three tumour models. Complete tumour response was achieved in 65% of Cal-33 and 91% of MOC22 tumour mouse models 14 days after PS-PDT, and partial responses obtained in 25% and 9% of Cal-33 and MOC22 tumours, respectively. In buccal VX-2 rabbit tumours, combined surface and interstitial PS-PDT (200 J total) yielded complete responses in only 60% of rabbits 6 weeks after a single treatment, whereas three repeated weekly treatments with PS-PDT (200 J/week) achieved complete ablation in 100% of tumours. PS-PDT treatments were well tolerated by animals with no treatment-associated toxicities and excellent cosmetic outcomes.

Evaluation of tumor microvasculature with 3D ultrasound localization microscopy based on 2D matrix array.

Evaluation of tumor microvascular morphology is of great significance in tumor diagnosis, therapeutic effect prediction, and surgical planning. Recently, two-dimensional ultrasound localization microscopy (2DULM) has demonstrated its superiority in the field of microvascular imaging. However, it suffers from planar dependence and is unintuitive. We propose a novel three-dimensional ultrasound localization microscopy (3DULM) to avoid these limitations. We investigated 3DULM based on a 2D array for tumor microvascular imaging. After intravenous injection of contrast agents, all elements of the 2D array transmit and receive signals to ensure a high and stable frame rate. Microbubble signal extraction, filtering, positioning, tracking, and other processing were used to obtain a 3D vascular map, flow velocity, and flow direction. To verify the effectiveness of 3DULM, it was validated on double helix tubes and rabbit VX2 tumors. Cisplatin was used to verify the ability of 3DULM to detect microvascular changes during tumor treatment. In vitro, the sizes measured by 3DULM at 3mm and 13mm were 178 and 182 , respectively. In the rabbit tumors, we acquired 9000 volumes to reveal vessels about 30 in diameter, which surpasses the diffraction limit of ultrasound in traditional ultrasound imaging, and the results matched with micro-angiography. In addition, there were significant changes in vascular density and curvature between the treatment and control groups. The effectiveness of 3DULM was verified in vitro and in vivo. Hence, 3DULM may have potential applications in tumor diagnosis, tumor treatment evaluation, surgical protocol guidance, and cardiovascular disease. 3D ultrasound localization microscopy is highly sensitive to microvascular changes; thus, it has clinical potential for tumor diagnosis and treatment evaluation. • 3D ultrasound localization microscopy is demonstrated on double helix tubes and rabbit VX2 tumors. • 3D ultrasound localization microscopy can reveal vessels about 30 in diameter-far smaller than traditional ultrasound. • This form of imaging has potential applications in tumor diagnosis, tumor treatment evaluation, surgical protocol guidance, and cardiovascular disease.

Emulsifying Lipiodol with pH-sensitive DOX@HmA nanoparticles for hepatocellular carcinoma TACE treatment eliminate metastasis

Lipiodol-based transcatheter arterial chemoembolization (TACE) is currently the predominant and first-line treatment option recommended by the global standard for unresectable hepatocellular carcinoma (HCC). However, the unstable emulsion of Lipiodol causes a substantial proportion of chemotherapy drugs to enter the circulation system, leading to poor accumulation in cancer tissues and unexpected side effects of chemotherapy drugs. Herein, we emulsified Lipiodol with a pH-sensitive drug delivery system assembled from hexahistidine and zinc ions (HmA) with a super-high loading capacity of doxorubicin (DOX) and a promising ability to penetrate bio-barriers for the effective treatment of HCC by TACE. In vitro tests showed that DOX@HmA was comparable to free DOX in killing HCC cells. Impressively, during the in vivo TACE treatment, the anti-tumor efficacy of DOX@HmA was significantly greater than that of free DOX, indicating that DOX@HmA increased the accumulation of DOX in tumor. Emulsifying Lipiodol with pH-sensitive DOX@HmA significantly inhibited cell regeneration and tumor angiogenesis and decreased the systemic side effects of chemotherapy, especially by suppressing pulmonary metastasis in liver VX2 tumors in rabbits by inhibiting epithelial–mesenchymal transition (EMT). Emulsifying tumor microenvironment-responsive drug delivery systems (DDSs) with Lipiodol could be a new strategy for clinical TACE chemotherapy with potentially enhanced HCC treatment.

Deep learning for fast denoising filtering in ultrasound localization microscopy

Objective. Addition of a denoising filter step in ultrasound localization microscopy (ULM) has been shown to effectively reduce the error localizations of microbubbles (MBs) and achieve resolution improvement for super-resolution ultrasound (SR-US) imaging. However, previous image-denoising methods (e.g. block-matching 3D, BM3D) requires long data processing times, making ULM only able to be processed offline. This work introduces a new way to reduce data processing time through deep learning. Approach. In this study, we propose deep learning (DL) denoising based on contrastive semi-supervised network (CS-Net). The neural network is mainly trained with simulated MBs data to extract MB signals from noise. And the performances of CS-Net denoising are evaluated in both in vitro flow phantom experiment and in vivo experiment of New Zealand rabbit tumor. Main results. For in vitro flow phantom experiment, the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of single microbubble image are 26.91 dB and 4.01 dB, repectively. For in vivo animal experiment , the SNR and CNR were 12.29 dB and 6.06 dB. In addition, single microvessel of 24 μm and two microvessels separated by 46 μm could be clearly displayed. Most importantly,, the CS-Net denoising speeds for in vitro and in vivo experiments were 0.041 s frame−1 and 0.062 s frame−1, respectively. Significance. DL denoising based on CS-Net can improve the resolution of SR-US as well as reducing denoising time, thereby making further contributions to the clinical real-time imaging of ULM.

Oxygen Imaging of a Rabbit Tumor Using a Human-Sized Pulse Electron Paramagnetic Resonance Imager.

Spatial heterogeneity in tumor hypoxia is one of the most important factors regulating tumor growth, development, aggressiveness, metastasis, and affecting treatment outcome. Most solid tumors are known to have hypoxia or low oxygen levels (pO2 ≤10 torr). Electron paramagnetic resonance oxygen imaging (EPROI) is an emerging oxygen mapping technology. EPROI utilizes the linear relationship between the relaxation rates of the injectable OX071 trityl spin probe and the partial oxygen pressure (pO2). However, most of the EPROI studies have been limited to mouse models of solid tumors because of the instrument-size limitations. The purpose of this work was to develop a human-sized 9-mT (250 MHz resonance frequency, 60 cm bore size) pulse EPROI instrument and evaluate its performance with rabbit VX-2 tumor oxygen imaging. A New Zealand white rabbit with a 3.2-cm VX-2 tumor in the calf muscle was imaged using the human-sized EPROI instrument and a 2.25-in. ID volume coil. The animal received a ~8-min intravenous injection of OX071 (5.2 mL total volume at 72 mM concentration) and, after 75 min, an intratumoral injection (120 μL total at 5 mM OX071 concentration) and underwent EPROI. At the end of the experiments, MRI was performed using a preclinical 9.4-T MRI system to outline the tumor boundaries. For the first time, a human-sized pulse EPROI instrument with a 60-cm bore size/250-MHz frequency was built and evaluated using rabbit tumor oxygen imaging. For the first time, the systemic IV injection of the oxygen-sensitive trityl OX071 spin probe was used for an animal of this size. The resulting EPROI image from the IV injection showed complete tumor coverage. The image obtained after intratumoral injection showed localized coverage in the upper lobe of the tumor, demonstrating the need for improved intratumoral injection protocol. This study demonstrates the performance of the world's first human-sized pulse EPROI instrument. It also demonstrates that the EPROI of larger animals can be performed using the systemic injection of a manageable amount of the spin probe. This brings EPROI one step closer to clinical applications in cancer therapies. Oxygen imaging is a platform technology, and the instrument and techniques developed here will also be useful for other clinical applications.

Efficacy, mechanism, and safety of melatonin-loaded on thermosensitive nanogels for rabbit VX2 tumor embolization: A novel design.

Transarterial chemoembolization (TACE) has been widely used for hepatocellular carcinoma.Reducing hypoxia in the tumor microenvironment after TACE remains a challenge as tumor progression is common in post-TACE patients due to the hypoxic tumor microenvironment. In this study, melatonin loaded on p(N-isopropyl-acrylamide-co-butyl methylacrylate) (PIB-M) was used for tumor embolism. Two types of human hepatoma cell lines were used to explore the mechanism by which melatonin prevents the growth and metastasis of cancer cells in vitro. A VX2 rabbit tumor model was used to evaluate the efficacy, mechanism, and safety of PIB-M in vivo. We found that under hypoxic condition, melatonin could inhibit tumor cell proliferation and migration by targeting hypoxia inducible factor-1α (HIF-1α) and vascular endothelial growth factor A (VEGF-A) in vitro. In vivo, PIB-M inhibited tumor growth and metastasis in rabbit VX2 tumors by promoting apoptosis of tumor cells and targeting related angiogenic proteins and vascular permeability proteins. A high concentration of melatonin in the PIB-M group could be maintained in tumor tissue for 72 h after embolization. The liver and kidney functions were most damaged on the first day but recovered to normal on the seventh day after embolization in the PIB-M group. This novel method may open avenues for reduction of tumor growth and metastasis after TACE and is efficacy and safety, which may be used for treatment for other solid tumors and clinical translation.

Intravoxel incoherent motion diffusion-weighted MRI assessing the effect of the vascular disrupting agent CA4P on VX2 liver tumors in rabbits.

This study aimed to assess the response of combretastatin-A4-phosphate (CA4P) in rabbit VX2 liver tumors using intravoxel incoherent motion diffusion-weighted MRI (IVIM DW-MRI). Forty rabbits with implanted VX2 liver tumors underwent baseline MRI and were then given 10 mg/kg CA4P (n=20) or saline (n=20). After 4 h, 10 rabbits from each group underwent an MRI examination and were then sacrificed. The remaining rabbits underwent MRI after 1, 3, and 7 days and were then sacrificed. Liver samples were processed for H&E and immunohistochemical staining. IVIM parameters (D, f, D*) were compared in the treatment and control groups, and the correlations of IVIM parameters with microvascular density (MVD) were determined. At 4 h, the two treatment groups had significantly different f and D* values (p<0.001), and these values were at their minimum in the treatment group. The treatment group had moderate correlations between MVD and f at 4 h (r=0.676, p=0.032) and 7 days (r=0.656, p=0.039) and with D* at 4 h (r=0.732, p=0.016) and 7 days (r=0.748, p=0.013), but no correlation was reported between MVD and f or D* in the control group (all P>0.05). IVIM DW-MRI is a sensitive imaging technique. It successfully evaluated the effect of CA4P on VX2 liver tumors in rabbits. The f and D* values correlated with MVD at 4 h and 7 days after using CA4P, indicating that these parameters have the potential to be used as indicators of tumor angiogenesis after treatment.

Spatiotemporally confined assembly of radiosensitizers for synergistic radio-chemodynamic therapy on deep tumor of rabbit

The controllable assembly of nanoparticles significantly improves their biological effects in vivo. However, it is difficult to realize the assembly regulation of nanomaterials under complex physiological conditions. Herein, endogenous glutathione (GSH)-triggered vesicles with spatiotemporally confined aggregation of gold nanogapped nanoparticles (AuNNPs) within vesicles were developed. These vesicles had excellent photoacoustic (PA) imaging capability in the near-infrared second window (NIR-II) for precise localization of deep tumors, measuring tumor volume, and making deep tumors more sensitive to radiotherapy and chemodynamic therapy (CDT). The vesicles were prepared via self-assembly of MnO2-coated AuNNPs that were functionalized by phosphate-polystyrene and bovine serum albumin (AuNNP@MnO2 Ve@BSA). The MnO2 shell was etched when AuNNP@MnO2 Ve@BSA vesicle was exposed to GSH, the gap between intra-vesicular AuNNP@MnO2 NPs was reduced. This significantly enhanced the plasmonic coupling effect between AuNNP@MnO2 NPs, giving it excellent NIR-II PA imaging capability, and thus can be used to delineate the boundary and volume of deep-seated tumors. Meanwhile, the Mn2+-mediated CDT released after the etching of the MnO2 shell interacted with GSH-responsive AuNNP@MnO2 Ve@BSA and significantly inhibited tumor growth due to enhanced radiosensitization effect. This unique strategy provides new perspectives and methods for designing and applying biomedical nanomaterials.

Efficacy and preliminary dose studies of ultrasound-guided sclerotherapy with lauromacrogol for the treatment of implanted hepatic tumors in rabbits.

To study the curative effect of sclerotherapy with lauromacrogol on a rabbit VX2 implanted liver tumor model, the effect of ultrasound-guided sclerotherapy with different doses of lauromacrogol in the treatment of the rabbit VX2 implanted liver tumor model and the degree of damage to the surrounding liver tissue was compared and observed. The relationship between the sclerosing effect and drug dose of lauromacrogol in the treatment of liver cancer is preliminarily discussed. Thirty rabbit models of liver cancer were randomly divided into 5 groups. Control Group A was injected with normal saline, control Group B was injected with absolute ethanol, experimental Group C was injected with lauromacrogol (Z =2.885D); the injection volume in experimental Group D was 1.5-fold higher than that in Group C; and the injection volume in experimental Group E was 2-fold higher than that in Group C. Changes in tumor volume were followed up by ultrasound before and 7 and 14 days after the operation; contrast-enhanced ultrasonography was used to measure the volume of the ablation area and volume rate. For pathological anatomy, hematoxylin and eosin (H&E) staining were used to observe tumor cell necrosis and the degree of damage to surrounding normal liver cells. The expression levels of the apoptosis-related protein cleaved-caspase 3 and the cell proliferation antigen Ki67 were examined by immunohistochemistry. The volumes in Groups A and C increased significantly. The volumes in Groups B, D, and E remained the same or slightly expanded, tumor growth in the three groups was significantly inhibited after sclerotherapy. Contrast-enhanced ultrasonography showed that the ablation volume and ablation volume rate in Groups B, D, and E were similar. Group C were smaller than those in the other treatment groups. Large coagulative necrotic foci were observed in the central area of tumors in Groups B, D, and E. The experiment demonstrates that lauromacrogol can inhibit tumor growth in the rabbit VX2 tumor model and cause VX2 tumor cell apoptosis. The sclerosing effect of the 1.5-fold amount of lauromacrogol is equivalent to that of absolute ethanol, with little effect on normal liver tissue.

A hepatocyte-targeting nanoparticle for enhanced hepatobiliary magnetic resonance imaging.

Hepatobiliary magnetic resonance imaging (MRI) can inform the diagnosis of liver tumours in patients with liver cirrhosis and hepatitis. However, its clinical utility has been hampered by the lack of sensitive and specific contrast agents, partly because hepatocyte-specific nanoparticles, regardless of their surface ligands, are readily sequestered by Kupffer cells. Here we show, in rabbits, pigs and macaques, that the performance of hepatobiliary MRI can be enhanced by an ultrasmall nanoparticle composed of a manganese ferrite core (3 nm in diameter) and poly(ethylene glycol)-ethoxy-benzyl surface ligands binding to hepatocyte-specific transmembrane metal and anion transporters. The nanoparticle facilitated faster, more sensitive and higher-resolution hepatobiliary MRI than the clinically used contrast agent gadoxetate disodium, a substantial enhancement in the detection rate (92% versus 48%) of early-stage liver tumours in rabbits, and a more accurate assessment of biliary obstruction in macaques. The nanoparticle's performance and biocompatibility support the further translational development of liver-specific MRI contrast agents.

Phosphotungstate Acid Doped Polyanilines Nanorods for in situ NIR-II Photothermal Therapy of Orthotopic Hepatocellular Carcinoma in Rabbit.

Second near-infrared photothermal therapy (NIR-II PTT) has become a promising strategy for treating cancer in terms of safety and potency. However, the application of NIR-II PTT was limited in the treatment of deep-buried solid tumors due to the low dose of NIR-II absorption nanomaterials and the inadequate laser energy in the deep tumor. Herein, the authors report the engineering of NIR-II absorbing polyaniline nanorods, termed HPW@PANI Nanorods, for in situ NIR-II PTT based on optical fibers transmission of laser power and transarterial infusion for the treatment of orthotopic hepatocellular carcinoma in the rabbit. HPW@PANI Nanorods were prepared via chemical oxidant polymerization of aniline under phosphotungstic acid, which exhibited effective NIR-II absorption for hyperthermia ablation cells. HPW@PANI Nanorods were fast and efficiently deposited into primary orthotopic transplantation VX2 tumor in rabbits via transarterial infusion. Furthermore, an optical fiber was interventionally inserted into the primary VX2 tumor to transmit 1064nm laser energy for in situ NIR-II PTT, which could ablate primary tumor, inhibit distant tumor, and suppress peritoneal metastasis. This study provides new insights into the application of in situ NIR-II PTT based on optical fibers transmission of laser power and transarterial injection of NIR-II absorption nanomaterials to treat deep-buried tumors.

Endoscopic Ultrasound Localization Microscopy for the Evaluation of the Microvasculature of Gastrointestinal Tract Tumors in Rabbits.

The morphological and hemodynamic characterization of the microvascular network around the gastrointestinal (GI) tract can be of significant clinical value for the early diagnosis and treatment of GI tract cancer. Ultrasound localization microscopy (ULM) imaging has been demonstrated to be capable of resolving the microvascular network. However, the endoscopic application of ULM imaging techniques is still unknown. In this study, an endoscopic ultrasound localization microscopy (e-ULM) imaging technique was developed to evaluate the changes of microvasculature during GI tract tumor growth. A customized circular array transducer (center frequency: 6.8 MHz) and the coherent diverging wave compounding method were used to generate B-mode images. Spatiotemporal singular value decomposition processing was used to eliminate the background signals before signal localizations. The centroids of spatially isolated signals were localized and summed to generate the final super-resolution image. The final microvasculature map of a rabbit GI tract tumor reveals that e-ULM can be used to surpass the diffraction limit in traditional endoscopic ultrasound (EUS) imaging. Furthermore, it is observed that data from different stages of tumor growth exhibit significant differences in microvascular pattern and density. Our study demonstrated the implementation and application of an in vivo e-ULM imaging technique for the evaluation of the microvasculature of GI tumors. The efficient e-ULM imaging technique shows potential for use in the detection of GI tract tumor microcirculation changes and subsequent diagnosis of GI tract cancer.

A VEGFR targeting peptide-drug conjugate (PDC) suppresses tumor angiogenesis in a TACE model for hepatocellular carcinoma therapy

Transcatheter arterial chemoembolization (TACE) has become the preferred therapy for unresectable advanced hepatocellular carcinoma (HCC). However, the embolization of tumor-feeding arteries by TACE always leads to hypoxia-related tumor angiogenesis, which limited the therapeutic effect for HCC. In this paper, we used a VEGFR targeting peptide VEGF125 − 136 (QKRKRKKSRYKS) to conjugate with a lytic peptide (KLUKLUKKLUKLUK) to form a peptide-drug conjugate (PDC). We used cell affinity assay to detect the peptide binding ability to VEGFR highly expressed cell lines, and CCK8, cell apoptosis to confirm the cellular toxicity for different cell lines. Meanwhile, we created a VX2 tumor-bearing rabbit model to assess the in vivo anti-tumor effect of the peptide conjugate in combination with TAE. HE staining was used to verify the in vivo safety of the peptide conjugate. IHC was used to assess the anti-angiogenesis and cell toxicity of the peptide conjugate in tumor tissues. The peptide conjugate could not only target VEGFR in cell surface and inhibit VEGFR function, but also have potent anti-cancer effect. We luckily found the peptide conjugate showed potent cytotoxicity for liver cancer cell Huh7 (IC50 7.3 ± 0.74 μM) and endothelial cell HUVEC (IC50 10.7 ± 0.292 μM) and induced cell apoptosis of these two cell lines. We also found the peptide conjugate inhibited cell migration of HUVEC through wound healing assay. Besides, these peptides also showed better in vivo anti-tumor effect than traditional drug DOX through TACE in VX2 rabbit tumor model, and efficiently inhibit angiogenesis in tumor tissues with good safety. In conclusion, our work may provide an alternative option for clinical HCC therapy via TACE combination.

Pharmacokinetics and Early Tumor Response to Conventional Transarterial Chemoembolization with Sorafenib and Doxorubicin in a VX2 Rabbit Tumor Model

PurposeTo investigate the pharmacokinetics (PK) and early effects of conventional transarterial chemoembolization (TACE) using sorafenib and doxorubicin on tumor necrosis, hypoxia markers, and angiogenesis in a rabbit VX2 liver tumor model. Materials and MethodsVX2 tumor-laden New Zealand White rabbits (N = 16) were divided into 2 groups: 1 group was treated with hepatic arterial administration of ethiodized oil and doxorubicin emulsion (DOX-TACE), and the other group was treated with ethiodized oil, sorafenib, and doxorubicin emulsion (SORA-DOX-TACE). Animals were killed within 3 days of the procedure. Levels of sorafenib and doxorubicin were measured in blood, tumor, and adjacent liver using mass spectrometry. Tumor necrosis was determined by histopathological examination. Intratumoral hypoxia-inducible factor (HIF) 1α, vascular endothelial growth factor (VEGF), and microvessel density (MVD) were determined by immunohistochemistry. ResultsThe median intratumoral concentration of sorafenib in the SORA-DOX-TACE group was 17.7 μg/mL (interquartile range [IQR], 7.42–33.5 μg/mL), and its maximal plasma concentration (Cmax) was 0.164 μg/mL (IQR, 0.0798–0.528 μg/mL). The intratumoral concentration and Cmax of doxorubicin were similar between the groups: 4.08 μg/mL (IQR, 3.18–4.79 μg/mL) and 0.677 μg/mL (IQR, 0.315–1.23 μg/mL), respectively, in the DOX-TACE group and 1.68 μg/mL (IQR, 0.795–4.08 μg/mL) and 0.298 μg/mL (IQR, 0.241–0.64 μg/mL), respectively, in the SORA-DOX-TACE group. HIF-1α expression was increased in the SORA-DOX-TACE group than in the DOX-TACE group. Tumor volume, tumor necrosis, VEGF expression, and MVD were similar between the 2 groups. ConclusionsThe addition of sorafenib to DOX-TACE delivered to VX2 liver tumors resulted in high intratumoral and low systemic concentrations of sorafenib without altering the PK of doxorubicin.

Precision cancer sono-immunotherapy using deep-tissue activatable semiconducting polymer immunomodulatory nanoparticles

Nanomedicine holds promise to enhance cancer immunotherapy; however, its potential to elicit highly specific anti-tumor immunity without compromising immune tolerance has yet to be fully unlocked. This study develops deep-tissue activatable cancer sono-immunotherapy based on the discovery of a semiconducting polymer that generates sonodynamic singlet oxygen (1O2) substantially higher than other sonosensitizers. Conjugation of two immunomodulators via 1O2-cleavable linkers onto this polymer affords semiconducting polymer immunomodulatory nanoparticles (SPINs) whose immunotherapeutic actions are largely inhibited. Under ultrasound irradiation, SPINs generate 1O2 not only to directly debulk tumors and reprogram tumor microenvironment to enhance tumor immunogenicity, but also to remotely release the immunomodulators specifically at tumor site. Such a precision sono-immunotherapy eliminates tumors and prevents relapse in pancreatic mouse tumor model. SPINs show effective antitumor efficacy even in a rabbit tumor model. Moreover, the sonodynamic activation of SPINs confines immunotherapeutic action primarily to tumors, reducing the sign of immune-related adverse events.

Magnesium galvanic cells produce hydrogen and modulate the tumor microenvironment to inhibit cancer growth

Hydrogen can be used as an anti-cancer treatment. However, the continuous generation of H2 molecules within the tumor is challenging. Magnesium (Mg) and its alloys have been extensively used in the clinic as implantable metals. Here we develop, by decorating platinum on the surface of Mg rods, a Mg-based galvanic cell (MgG), which allows the continuous generation of H2 in an aqueous environment due to galvanic-cell-accelerated water etching of Mg. By implanting MgG rods into a tumor, H2 molecules can be generated within the tumor, which induces mitochondrial dysfunction and intracellular redox homeostasis destruction. Meanwhile, the Mg(OH)2 residue can neutralize the acidic tumor microenvironment (TME). Such MgG rods with the micro-galvanic cell structure enable hydrogen therapy to inhibit the growth of tumors, including murine tumor models, patient-derived xenografts (PDX), as well as VX2 tumors in rabbits. Our research suggests that the galvanic cells for hydrogen therapy based on implantable metals may be a safe and effective cancer treatment.

Cutaneous and Subcutaneous Tumours of Small Pet Mammals-Retrospective Study of 256 Cases (2014-2021).

Simple SummarySeveral species of small mammals are very popular as companion pet animals and therefore demand professional veterinary care, including proper diagnostic and treatment procedures. The incidence of neoplastic diseases in companion pet animals has increased over time, as it has in humans. The aim of this study was to evaluate the incidence of cutaneous tumours in small mammal pets, including guinea pigs, rats, pet rabbits, ferrets, hamsters, degus, African pygmy hedgehogs, Mongolian gerbils and chinchillas, submitted for histopathology in 2014–2021. Malignant tumours represented the predominant group of cutaneous tumours in rats, African pygmy hedgehogs, degus and chinchillas, and represented a significant percentage of lesions in guinea pigs, pet rabbits, ferrets, hamsters and Mongolian gerbils. We also described the first case of melanocytoma in a pet rabbit, epitheliotropic T-cell lymphoma in a degu, cutaneous histiocytic sarcoma in a Mongolian gerbil, fibrosarcoma in two chinchillas and epithelioid haemangioma in a chinchilla. The incidence of malignant neoplasms among spontaneous integumentary tumours submitted for histopathology is high in many species of small mammal pets. Therefore, each cutaneous tumour should be sampled for further diagnosis and treatment.Since small mammals are gaining popularity as pets in Poland, the number of tumour samples submitted for histopathological examination is quite high. This study was a retrospective analysis of cutaneous and subcutaneous tumours in small pet mammals submitted for histopathology in 2014–2021. The analysis included 256 tumours sampled from 103 guinea pigs, 53 rats, 43 pet rabbits, 21 ferrets, 17 hamsters, 8 degus, 5 African pygmy hedgehogs, 3 Mongolian gerbils and 3 chinchillas. Tumours were diagnosed based on routine histopathology, with additional immunohistochemistry when necessary. The results of this study revealed that the vast majority of cutaneous tumours in guinea pigs were benign, with a predominance of lipoma. Adnexal tumours constituted a significant percentage of cutaneous tumours in guinea pigs (24.3%, with the most common being trichofolliculoma), pet rabbits (46.5%, with the most common being trichoblastoma), ferrets (33.3%, mostly derived from sebaceous glands), hamsters (52.9%, with the most common being trichoepithelioma) and gerbils (66.7%, scent gland epithelioma). Soft tissue sarcomas were a predominant group of tumours in rats (52.8%, with the most common being fibrosarcoma), African pygmy hedgehogs (100%), degus (87.5%) and chinchillas (66.7%). Melanocytic tumours were only sporadically seen in small mammal pets. Mast cell tumours were diagnosed only in ferrets, while epitheliotropic T-cell lymphoma was diagnosed only in a hamster and a degu. In summary, malignant tumours constitute a significant percentage of cutaneous tumours in many species of small mammal pets. Therefore, each cutaneous tumour should be sampled for further cytologic or histopathologic diagnosis.

Prospective survey of neoplastic and non-neoplastic uterine disorders in 116 domestic rabbits (Oryctolagus cuniculus)

Earlier studies indicate that the risk for uterine tumours in rabbits may be as high as 60–80%. This high occurrence and the need for routine neutering of non-breeding pet rabbits have recently been in the spotlight. This study aimed to describe and compare macroscopic and histopathological alterations in uteri collected from domestic rabbits of various ages that were neutered, deceased, or euthanized without a suspected uterine disorder (NoUD; n = 94) and from rabbits with a suspected uterine disorder (UD; n = 22). In the NoUD group, uteri of 41 rabbits (44%) displayed histopathological findings and 12 rabbits (13%) had neoplasms. Samples from thirteen rabbits (14%) evinced histopathological findings with no macroscopic alterations. The most frequent diagnoses were cystic endometrial hyperplasia (26% of the 41 uteri), adenocarcinoma (9%), and polyps (5%). In the UD group, uteri from 21 (95%) out of 22 rabbits exhibited pathological alterations; in 2 (10%) of these, the changes (cystic endometrial hyperplasias) were seen only in histology. The most frequent diagnoses in the uteri of the UD group were cystic endometrial hyperplasia (77%) and adenocarcinoma (54%). Uterine malignant neoplasia affected 40% of all rabbits aged over 3 years, and the odds of a malignant uterine tumour in these rabbits were approximately 19-fold higher than in rabbits aged under 3 years. Uterine disorders are common in domestic rabbits, even without a suspected uterine disease, and the risk of uterine neoplasia markedly increases after 3 years of age. A macroscopically normal uterus may have pathological changes and ovariohysterectomy should be therefore preferred over ovariectomy at least in older rabbits.

Engineering bioluminescent bacteria to boost photodynamic therapy and systemic anti-tumor immunity for synergistic cancer treatment

The limited penetration depth of external excitation light would remarkably impair the therapeutic efficacy of photodynamic therapy (PDT) and its clinical utilization. Herein, we engineered bioluminescent bacteria by transforming attenuated Salmonella typhimurium strain ΔppGpp (S.T.ΔppGpp) with firefly-luciferase-expressing plasmid (Luc-S.T.ΔppGpp) as an internal light source to evenly illuminate whole tumors. Upon being fixed inside tumors with in-situ formed hydrogel, the colonized Luc-S.T.ΔppGpp together with D-luciferin could continuously generate light to excite photosensitizer chlorin e6 (Ce6), leading to effective suppression of different types of tumors including opaque melanoma and large rabbit tumors. Such bioluminescence-triggered PDT presented significant advantages over conventional PDT excited with an external 660-nm light, which at a much high light energy could only slightly retard the growth of small subcutaneous tumors. Furthermore, we uncovered that Luc-S.T.ΔppGpp boosted PDT could also elicit potent antitumor immunity post the treatment to inhibit tumor metastasis and prevent tumor challenge. Therefore, this work highlights that such bioluminescent bacteria boosted PDT is a general and highly effective therapeutic approach toward diverse cancers with varying light-absorbing capacities and tumor sizes, promising for potential clinical translation because of their acceptable safety profiles.