Vol 29, No 3 (2024)

BACKGROUND: Developing biosimilar monoclonal antibodies for treating malignant diseases is a critical task. RPH-051 (pertuzumab) is a biosimilar drug, a recombinant humanized monoclonal antibody targeting type 2 human epidermal growth factor receptors. At the stage of non-clinical development, studies of pharmacokinetics of biosimilar vs. original drug product in a relevant animal species, provide important information on the comparability of drugs.

AIM: To evaluate the pharmacokinetics of the biosimilar product RPH-051 in comparison with the original drug after a single intravenous injection in a cynomolgus monkey model.

MATERIALS AND METHODS: The study was conducted in 8 cynomolgus monkeys (Macaca fascicularis) divided into 2 groups, each including 2 females and 2 males. The first group received the biosimilar RPH-051 (international nonproprietary name is pertuzumab, AO R-Pharm, Russia), the second group was treated with the comparator Perjeta^® (international nonproprietary name is pertuzumab). The drugs were administered as a single intravenous dose of 50 mg/kg. Blood samples were collected before dosing, then at 1 min, 1, 2, 4, 8, 24 h, and on days 3, 7, 10, 14, 21 and 28 post-dosing. Quantitative analysis of pertuzumab serum levels was performed using enzyme-linked immunosorbent assay (ELISA) with spectrophotometric detection in the visible range of the spectrum.

RESULTS: The method of quantitative assessment of serum level of pertuzumab using (ELISA) in cynomolgus monkeys was developed. The method was validated against the following parameters: selectivity, minimum required dilution, lower limit of quantification, calibration range, accuracy and precision (within the analytical run and between runs), specificity, linearity (possibility) of sample dilution, parallelism, and stability of the analyte in serum.

Comparability of the drugs in the main pharmacokinetic parameters was established. The mean C_max and AUC_last values of RPH-051 and of the comparator were 1684.34 and 1405.34 μg/mL (C_max); 265,282.18 and 280,168.92 (μg/mL)×h (AUC_last), respectively.

CONCLUSION: Comparability between the pharmacokinetic profiles of the biosimilar RPH-051 and the originator’s drug was demonstrated. In the course of the study, no adverse clinical events, animal body weight changes, or injection site reactions associated with the tested drugs were observed.

BACKGROUND: Cervical cancer (CC) is the fourth most common cancer among women worldwide in terms of incidence and mortality. High-risk human papillomaviruses (HPVs) are etiologic factor of CC in more than 90% of cases, with type 16 HPV (HPV16) revealed in >50% of cancers. Dysregulation of expression of viral oncogenes E6 and E7 is the main cause of malignant transformation in infected cervical epithelial cells. The mechanisms of impaired expression of these genes are still underexplored. The dysfunction of viral microRNAs may be among the underlying factors.

AIM: To analyze the expression of HPV16-associated microRNA-H1 and microRNA-H2 in cervical cancer specimens, evaluate the correlation of their expression to viral load and overall patient survival, and analyze in silico their potential viral and cellular targets.

MATERIALS AND METHODS: The expression of HPV16 microRNA-H1 and HPV16 microRNA-H2 was evaluated in the real-time polymerase chain reaction. With this purpose, small RNAs were isolated from 36 specimens of HPV16-positive squamous cell carcinomas of the cervix. Further, the viral load was assessed after calculating the value of HPV16 DNA copies per cell. The association between microRNA expression and the viral load was evaluated using the nonparametric Spearman’s correlation coefficient. Kaplan-Meier curves were plotted to analyze the dependence of 5-year overall survival on the level of viral microRNA expression. The miRanda algorithm and online services mirDB, MR-microT and TargetScan Custom 5.2 were used for in silico search of theoretical microRNA targets.

RESULTS: MicroRNA-H1 expression was revealed in 33 of 38 specimens (86.8%), microRNA-H2 was detected in 37 of 38 specimens (97.4%) of HPV16-positive cervical cancer. There was a positive correlation between both microRNA-H1 (r=0.36, p=0.042) and microRNA-H2 (r=0.51, p=0.001) expression and HPV16 viral load. Higher level of expression of viral microRNA-H1 and microRNA-H2 tended to correlate with better overall patient survival. The theoretical microRNA-H1 (E7, E2, E5, L2 and URR) and microRNA-H2 (E1, E2, E5, L2, L1, URR) targets in the HPV16 genome were identified in silico, as well as theoretical cellular targets indicating possible regulation of cellular signaling pathways by means of viral microRNAs, both controlling normal viral cycle and promoting tumor transformation.

CONCLUSION: The results of this study demonstrate promising further investigation of the functions of viral microRNAs in relation with the infectious process and virus-induced malignant transformation, and their potential importance in the diagnosis of HPV16-associated cancers.

BACKGROUND: Developing new platinum-based antitumor agents with improved efficacy and reduced toxicity remains a critical challenge. One promising approach is the synthesis of Pt(IV) prodrugs, such as precursor complexes of cisplatin and its analogs, which release active Pt(II) directly into the intracellular environment of malignant cells. To determine the optimal administration route for these new platinum-based drugs in vivo, it is essential to study their acute toxicity and biodistribution in vital organs.

AIM: To evaluate the tolerability, acute toxicity, biodistribution, and accumulation in breast tumors of Riboplatin and its liposomal formulation.

MATERIALS AND METHODS: The study was conducted at Moscow Pedagogical State University in female BALB/c mice (healthy or bearing transplanted breast adenocarcinoma EMT-6) and in immunodeficient BALB/c nude mice (bearing human breast adenocarcinoma SK-BR-3). The fluorescence imaging and inductively coupled plasma mass spectrometry were used.

RESULTS: A single dose (up to 48 mg/kg) of either water solution or liposomal formulation of Riboplatin did not cause any decrease of body weight in mice. The animals tolerated the dose 48 mg/kg of the drug, whereas the body weight decreased by less than 5% within 3 days. The distribution of Riboplatin and of its liposomal formulation over the body organs was assessed in BALB/c nude mice using fluorescence imaging and inductively coupled plasma mass spectrometry. Both forms provided Riboplatin delivering to EMT-6 tumor. Riboplatin in the form of water solution was predominantly excreted through liver and kidney, while the liposomal formulation lewd to drug accumulation in the spleen.

CONCLUSION: Riboplatin is a Pt(IV) prodrug with good tolerability, reduced toxicity compared with cisplatin, with effective accumulation in malignant breast tumors. The opportunity of assessing Riboplatin biodistribution in vivo in EMT-6 and SK-BR-3 tumor lines using fluorescence imaging has been demonstrated. Significant Riboplatin accumulation in EMT-6 tumors suggests the possibility of riboflavin-specific uptake.

BACKGROUND: Nanosystems based on magnetic nanoparticles (MNPs) of iron oxides coated with human serum albumin (HSA) have a set of unique characteristics that make their use promising in the diagnosis and treatment of tumors.

AIM: To investigate, using in vitro and in vivo models, the possibilities of using the systems we developed based on MNPs magnetite, modified by HSA using the free radical method, for contrasting tumors and slowing their growth.

MATERIALS AND METHODS: The stability and integrity of the albumin coating formed on synthesized nanoparticles as a result of protein adsorption and fixation of adsorbed albumin molecules on nanoparticles due to modification of albumin by the action of a hydroxyl radical formed in a Fenton-like reaction was controlled by a change in the apparent optical density by 450 nm with the addition of immunoglobulin G. After in vitro confirmation of the contrasting properties and possible consequences of the contact of MNPs and nanosystems with blood by agglutination test, nanosystems containing MNPs and HSA were injected intraarterially into tumors implanted in rats at a dose of 20–60 μg per animal and the contrasting properties were studied in vivo using radiography and computed tomography. The effect of nanosystems on the tumor was assessed by the tumor growth index (TGI) and by the results of a pathomorphological study.

RESULTS: To obtain nanosystems, joint incubation of MNPs and HSA was carried out for 24 hours in the presence of hydrogen peroxide, then subjected to magnetic separation. The stability and integrity of the protein coatings were confirmed with the addition of immunoglobulin G. In vitro studies have shown that the resulting nanosystem preparation in an aqueous medium with a MNPs concentration of 200 μg/ml does not lead to agglutination of blood cells and has a pronounced contrast. Vascular contrast in vivo, recorded 30 minutes after intraarterial administration, persisted for 14 days of follow-up. The tolerability study did not reveal any adverse side effects. With the introduction of nanosystems, a significant inhibition of tumor growth was noted compared with the control groups (p ≤0.05). Thus, tumors without the introduction of nanosystems reached a volume of 95,726.9±38,040.3 mm³ during the observation period — the TGI was 11±4.5. In the groups of rats treated with nanosystems at a dose of 20 micrograms of MNPs, tumors grew to 49,801±6011.2 mm³ (TGI 4.7±0.5), at a dose of 40 μg of MNPs — to 54,670.2±17 983.4 mm³ (IPO 5.5±1.4), at a dose of 60 μg of MNPs — to 43,342.5±14,637.2 mm³ (TGI 4.5±1.3).

CONCLUSION: The steady contrast of tumor vessels with the introduction of nanosystems based on MNPs and HSA and their cytotoxic effect on the tumor is shown, which gives reason to consider the nanosystems developed by us promising for tumor theranostics.

This review presents data concerning claudins, the proteins of tight junctions, and their role in the pathogenesis and therapy of malignancies. Particular attention is paid to the variability in claudin expression levels, their intracellular localization in tumors, and the prognostic significance of these variations in cancer. The review highlights the role of claudins in metastatic spread, invasion, and tumor cell resistance to antitumor drug therapy. Moreover, the potential of claudins as targets for novel diagnostic and treatment methods for malignant neoplasms is also discussed.