Andrzej Rapak

Background/Objectives: Canine Diffuse Large B-cell Lymphoma (cDLBCL) is characterized by a high prevalence of MHC II DR (DLA-DR) antigen overexpression. Murine anti-pan-DLA-DR monoclonal antibodies (mAbs) B5 and E11 have been previously observed to promote death of cDLBCL cells in vitro and in vivo. Consequently, DLA-DR antigens are considered a prospective target for passive immunotherapy aside from CD20. While infusion of anti-pan MHC II mAbs has demonstrated tumor suppression in cDLBCL xenografted immunodeficient mice, the relative contributions of direct cellular versus immune-mediated mechanisms to this therapeutic effect remain undefined. This study aimed to dissect these potential mechanisms of mAb E11. Methods: Canine lymphoma and leukemia cell lines CLBL1 and CLB70 were incubated with full E11 antibody or its F(ab′)2 and Fab fragments and cell viability was assessed with sub-G1 assay then, NOD-SCID mice were xenotransplanted with 1.5 × 10⁷ canine CLBL1 cells expressing nanoluciferase and were infused either with mAb E11 or its fragments, each at 1 mg/kg body mass, twice weekly for three consecutive weeks. Tumor burden was monitored by assessing body weight, nanoluciferase activity in blood, and by flow cytometric analyses of bone marrow tumor cell content. Time to tumor progression (TTP) was calculated based on weight loss and luminescence measurements. Results: We observed cytotoxic activity of monovalent E11-Fab fragments in vitro and in vivo. The mean TTP for mice treated with irrelevant mouse IgG antibodies was 9.8 ± 4.65 days. In contrast, treatment with E11 Fab fragments resulted in a TTP of 19.1 ± 2.67 days, which was similar to that achieved with the full E11 mAb (19.5 ± 1.73 days) and E11 F(ab′)2 fragments (18.1 ± 2.9 days). Conclusions: Our findings demonstrate a potent antibody cytotoxicity mechanism that operates in vivo and is independent of cell surface MHC II crosslinking or Fc engagement. These data support the promising potential of E11-Fab fragments for further clinical development as a therapeutic agent in canine lymphoma.

Background/Objectives: Gingipains produced by P. gingivalis have been shown to be directly related to periodontal tissue degradation and are significant molecular targets in therapy of periodontitis. Blocking the activity of these enzymes should reduce survival of this pathogen and mitigate the effects of inflammation in periodontitis. Therefore, gingipains inhibitors and specific antibodies could be recommended in the treatment of periodontitis. Cysteine peptidase inhibitors can be obtained by chemical synthesis, or isolated from natural raw materials. This research has the following aims: 1. to analyze in vitro the inhibition of cysteine protease activity in the gingival crevicular fluid (GCF) and 2. to compare the toxicity of natural raw inhibitors (obtained from Fallopia japonica plant and egg white) with chlorhexidine (CHX) using an MTS viability test. Methods: Samples of GCF were collected from healthy (N = 17) individuals and (N = 65) periodontal patients. Cysteine peptidase activity was inhibited by adding a solution of cystatin from egg white (with 20% glycerol), or cystatin from knotweed, or low molecular weight inhibitors (MW < 3 kDa) from egg white and knotweed against Nα-Benzoyl-DL-arginine 4-nitroanilide hydrochloride. Results: There was a statistically significant difference between the inhibition means of cysteine protease activity for the five groups (p < 0.001). Means for the four groups of patients with periodontitis were not statistically significant different from each other (p = 0.320). The inhibition rates were higher in periodontitis patients. The toxicity of knotweed cystatin inhibitor was several times lower than the toxicity of E-64d, and of CHX. Conclusion: Cysteine protease inhibitors isolated from egg or plants were non-toxic, effectively inhibited the activity of cysteine proteases in GCF, and may be a promising alternative to more toxic standard antimicrobials (CHX) in preventing periodontal tissue breakdown.

In this research, we developed boron-rich nanoparticles that can be used for boron neutron capture therapy as potential carriers for boron delivery to cancerous tissues. Functionalized carbonated boron nitride nanostructures (CBNs) were successfully synthesized in self-propagating combustion waves in mixtures of high-nitrogen explosives and boron compounds. The products’ composition, morphology, and structural features were investigated using Fourier transform infrared spectroscopy, powder X-ray diffraction, low-temperature nitrogen sorption analysis, thermogravimetric analysis, high-resolution scanning electron microscopy, and high-resolution transmission electron microscopy. The extreme conditions prevailing in combustion waves favor the formation of nanosized CBN hollow grains with highly disordered structures that are properly functionalized on the surface and inside the particles. Therefore, they are characterized by high porosity and good dispersibility in water, which are necessary for medical applications. During biological tests, a concentration-dependent effect of the obtained boron nitride preparations on the viability of normal and neoplastic cells was demonstrated. Moreover, the assessment of the degree of binding of fluorescently labeled nanoparticles to selected cells confirmed the relationships between the cell types and the concentration of the preparation at different incubation time points.

Cornelian cherry (Cornus mas L.) fruits, abundant in iridoids and anthocyanins, are natural products with proven beneficial impacts on the functions of the cardiovascular system and the liver. This study aims to assess and compare whether and to what extent two different doses of resin-purified cornelian cherry extract (10 mg/kg b.w. or 50 mg/kg b.w.) applied in a cholesterol-rich diet rabbit model affect the levels of sterol regulatory element-binding protein 1c (SREBP-1c) and CCAAT/enhancer binding protein α (C/EBPα), and various liver X receptor-α (LXR-α), peroxisome proliferator-activated receptor-α (PPAR-α), and peroxisome proliferator-activated receptor-γ (PPAR-γ) target genes. Moreover, the aim is to evaluate the resistive index (RI) of common carotid arteries (CCAs) and aortas, and histopathological changes in CCAs. For this purpose, the levels of SREBP-1c, C/EBPα, ATP-binding cassette transporter A1 (ABCA1), ATP-binding cassette transporter G1 (ABCG1), fatty acid synthase (FAS), endothelial lipase (LIPG), carnitine palmitoyltransferase 1A (CPT1A), and adiponectin receptor 2 (AdipoR2) in liver tissue were measured. Also, the levels of lipoprotein lipase (LPL), visceral adipose tissue-derived serine protease inhibitor (Vaspin), and retinol-binding protein 4 (RBP4) in visceral adipose tissue were measured. The RI of CCAs and aortas, and histopathological changes in CCAs, were indicated. The oral administration of the cornelian cherry extract decreased the SREBP-1c and C/EBPα in both doses. The dose of 10 mg/kg b.w. increased ABCA1 and decreased FAS, CPT1A, and RBP4, and the dose of 50 mg/kg b.w. enhanced ABCG1 and AdipoR2. Mitigations in atheromatous changes in rabbits’ CCAs were also observed. The obtained outcomes were compared to the results of our previous works. The beneficial results confirm that cornelian cherry fruit extract may constitute a potentially effective product in the prevention and treatment of obesity-related disorders.

Cornelian cherry (Cornus mas L.) fruits, abundant in iridoids and anthocyanins, are natural products with proven beneficial impact on the functions of the cardiovascular system and the liver. The aim of this study is to stipulate and compare whether and to what extent two different doses of resin-purified cornelian cherry extract (10 mg/kg b.w. or 50 mg/kg b.w.) applied in a cholesterol-rich diet rabbit model affect the levels of ATP-binding cassette transporter A1, ATP-binding cassette transporter G1, CCAAT/enhancer binding protein α, sterol regulatory ele-ment-binding protein 1c, fatty acid synthase, endothelial lipase, carnitine palmitoyltransferase 1A, and adiponectin receptor 2 in liver tissue; lipoprotein lipase, visceral adipose tissue-derived serine protease inhibitor, and retinol-binding protein 4 in visceral adipose tissue; resistive index of com-mon carotid arteries and aortas, and histopathological changes in CCAs. Obtained outcomes are referred to the results of our previous works. Moreover, our study, to our knowledge, test the in-fluence of Cornus derivative on CPT1A, AdipoR2, RBP4, LIPG, and vaspin for the first time, with a relevant outcome for the first three. Oral administration of the cornelian cherry extract decreased the SREBP-1c and C/EBPα in both doses. The dose of 10 mg/kg b.w. increased ABCA1 and de-creased FAS, CPT1A, and RBP4, and the dose of 50 mg/kg b.w. enhanced ABCG1 and AdipoR2. Mitigation in atheromatous changes in rabbits’ CCAs was also observed. The beneficial results confirm that cornelian cherry fruit extract may constitute a potentially effective product in the prevention and treatment of obesity-related disorders.

Xanthohumol is a cancer chemopreventive agent that can interfere with the initiation, promotion, and progression phase of carcinogenesis via a variety of inhibitory mechanisms. Xanthohumol was reported as an effective agent against leukemia/lymphoma cells. In the present study, we investigated the effect of xanthohumol and its natural and semisynthetic derivatives against various canine leukemia/lymphoma cell lines. Xanthohumol, three hops minor prenylflavonoids (xanthohumol C, xanthohumol D, α,β-dihydroxanthohumol) and four derivatives obtained by biotransformation (xanthohumol 4′-O-β-D-(4‴-O-methyl)-glucopyranoside) as well as by chemical modification (1″,2″-dihydroxanthohumol K, 2,3-dehydroisoxanthohumol, (Z)-6,4′-dihydroxy-4-methoxy-7-prenylaurone) were tested for their antiproliferative and pro-apoptotic activities against the following canine leukemia/lymphoma cell lines: CLBL-1 (B-cell lymphoma), CLB70 (B-cell leukemia), and GL-1 (B-cell leukemia). The compounds were tested at a final concentration range of 0.1–30 µM for 48 h. All eight of the tested flavonoids exerted concentration-dependent cytotoxicity in the selected canine lymphoma/leukemia cell lines. Three compounds markedly decreased the viability of all cell lines with IC₅₀ in the range of 0.5 to 8 μM. Double-staining of the treated cells with AnnexinV and propidium iodide revealed that the dying cells were mostly in the late apoptosis stage. ROS production and changes in mitochondrial potential were detected. Western blot analysis showed a decreased expression of Bcl-2. Canine lymphoma and leukemia cell lines are sensitive to xanthohumol derivatives, and the compounds acted through an apoptotic cell-death mechanism. These compounds, either used alone or in combination with other therapies, may be useful for the treatment of canine leukemia/lymphoma.

Resveratrol (RES) is gaining recognition as a natural bioactive compound. To expand the possible applications of RES with its enhanced bioactivity as well as to increase the health benefits of long-chain fatty acids, a lipophilization process of RES was performed using three fatty acids: palmitic acid (PA), oleic acid (OA), and conjugated linoleic acid (CLA). The obtained mono-, di-, and tri-esters of RES were evaluated for their anticancer and antioxidant properties against lung carcinoma (A549), colorectal adenocarcinoma (HT29), and pancreatic ductal adenocarcinoma (BxPC3) cell lines. Human fibroblast (BJ) cells were used as a control. Several parameters were investigated: cell viability and apoptosis, including the expression of major pro- and anti-apoptotic markers, as well as the expression of superoxide dismutase, a key enzyme of the body’s antioxidant barrier. Three of the obtained esters: mono-RES-OA, mono-RES-CLA, and tri-RES-PA, which significantly reduced the tumor cell viability up to 23%, at concentrations 25, 10, 50 μg/mL, respectively, turned out to be particularly interesting. The above-mentioned resveratrol derivatives similarly increased the tumor cells’ apoptosis by modifying their caspase activity of pro-apoptotic pathways (p21, p53, and Bax). Moreover, among the mentioned esters, mono-RES-OA induced apoptosis of the analyzed cell lines most strongly, reducing the number of viable cells up to 48% for HT29 cells versus 36% for pure RES. Furthermore, the selected esters exhibited antioxidant properties towards the normal BJ cell line by regulating the expression of major pro-antioxidant genes (superoxide dismutases—SOD1 and SOD2) without the effect on their expression in the tumor, and therefore reducing the defense of cancer cells against increased oxidative stress induced by high ROS accumulation. The obtained results indicate that the esters of RES and long-chain fatty acids allow enhancement of their biological activity. The RES derivatives have the potential for being applied in cancer prevention and treatment, as well as for oxidative stress suppression.

The present work aims to assess the biological potential of polyphenolic compounds in different parts (flowers, leaves, stems, and roots) of Stachys palustris L. Towards secondary metabolites profile, 89 polyphenolic compounds (PCs) were identified by UPLC-PDA-ESI-TQD-MS/MS, with a total average content of 6089 mg/100 g of dry matter (d.m.). In terms of biological activity, antioxidant activity (radical activity, reducing power), digestive enzyme inhibitory (α-glucosidase, α-amylase, pancreatic lipase) effect, and antiproliferative activity (inhibition of cell viability and induction of apoptosis in different human cancer cell lines) were explored. Leaves, flowers, stems, and roots of S. palustris L. have not been studied in this regard until now. Vescalagin and cocciferin d2, isoverbascoside (verbascoside), luteolin 6-C-glucoside, luteolin 6-C-galactoside, apigenin 6-C-glucoside, (−)-epicatechin, ellagic acid, and malvidin 3-O-diglucoside were detected as main ingredients in the studied parts. Methanolic extract of S. palustris L. leaves and flowers revealed the highest amount of PCs with the strongest antiradical (18.5 and 15.6 mmol Trolox equivalent (TE)/g d.m., respectively) and reducing power effects (7.3 and 5.6 mmol TE/g d.m.). Leaf extracts exhibited better α-amylase and pancreatic lipase inhibition effects, while flower extracts exhibited better α-glucosidase inhibition effect. Regarding antiproliferative activity, extracts of the leaves and flowers significantly reduced cell viability and induced a high level of apoptosis in human lung, pancreatic, bladder, and colon cancer cell lines, as well as in human acute myeloid leukemia; whereas the extracts from stems and roots revealed the weaker effects. The results of this work showed anti-proliferative and potentially anti-diabetic, anti-obesity properties of S. palustris L., especially for flowers and leaves, which may have wide potential applications in the functional food, special food, pharmaceutical, cosmetics industries, and/or in medicine.

Cornelian cherry (Cornus mas L.) fruits possess potential cardiovascular, lipid-lowering and hypoglycemic bioactivities. The aim of this study is to evaluate the influence of resin-purified cornelian cherry extract rich in iridoids and anthocyanins on several transcription factors, intima/media ratio in aorta and serum parameters, which determine or are valuable indicators of the adverse changes observed in the course of atherosclerosis, cardiovascular disease, and metabolic syndrome. For this purpose, male New Zealand rabbits were fed a diet enriched in 1% cholesterol for 60 days. Additionally, one group received 10 mg/kg b.w. of cornelian cherry extract and the second group 50 mg/kg b.w. of cornelian cherry extract. PPAR-α and PPAR-γ expression in the aorta, LXR-α expression in the liver; cholesterol, triglycerides, adipokines, apolipoproteins, glucose and insulin levels in serum; the intima and media diameter in the thoracic and abdominal aorta were determined. Administration of cornelian cherry extract resulted in an enhancement in the expression of all tested transcription factors, a decrease in triglycerides, leptin and resistin, and an increase in adiponectin levels. In addition, a significant reduction in the I/M ratio was observed for both the thoracic and abdominal aorta. The results we have obtained confirm the potential contribution of cornelian cherry extract to mitigation of the risk of developing and the intensity of symptoms of obesity-related cardiovascular diseases and metabolic disorders such as atherosclerosis or metabolic syndrome.

The aim of the work was to study the interaction between boron-rich boron carbide nanoparticles and selected tumor and immune phagocytic cells. Experiments were performed to investigate the feasibility of the application of boron carbide nanoparticles as a boron carrier in boron neutron capture therapy. Boron carbide powder was prepared by the direct reaction between boron and soot using the transport of reagents through the gas phase. The powder was ground, and a population of nanoparticles with an average particle size about 80 nm was selected by centrifugation. The aqueous suspension of the nanoparticles was functionalized with human immunoglobulins or FITC-labeled human immunoglobulins and was then added to the MC38 murine colon carcinoma and to the RAW 264.7 cell line of mouse macrophages. Flow cytometry analysis was used to determine interactions between the functionalized boron carbide nanoparticles and respective cells. It was shown that B₄C–IgG nanoconjugates may bind to phagocytic cells to be internalized by them, at least partially, whereas such nanoconjugates can only slightly interact with molecules on the cancer cells’ surface.