Comparative Study of Antitumor Efficiency of Intraperitoneal and Intravenous Cytostatics in Experimental Rats with Disseminated Ovarian Cancer

Nanomedicines Bearing an Alkylating Cytostatic Drug from the Group of 1,3,5-Triazine Derivatives: Development and Characterization

Cancer is still one of the major diseases worldwide. The discovery of new drugs and the improvement of existing ones is one of the areas of priority in the fight against cancer. Dioxadet ([5-[[4,6-bis(aziridin-1-yl)-1,3,5-triazin-2-yl]amino]-2,2-dimethyl-1,3-dioxan-5-yl]methanol) represents one of the promising 1,3,5-triazine derivatives and has cytostatic activity towards ovarian cancer. In this study, we first report the development of dioxadet-bearing nanomedicines based on block-copolymers of poly(ethylene glycol) monomethyl ether (mPEG) and poly(D,L-lactic acid) (PLA)/poly(ε-caprolactone) (PCL) and then conduct an investigation into their characteristics and properties. The preparation of narrow-sized nanoparticles with a hydrodynamic diameter of 100−120 nm was optimized using a nanoprecipitation approach. Thoughtful optimization of the preparation of nanomedicines was carried out through adjustments to the polymer’s molecular weight, the pH of the aqueous medium used for nanoprecipitation, the initial drug amount in respect to the polymer, and polymer concentration in the organic phase. Under optimized conditions, spherical-shaped nanomedicines with a hydrodynamic diameter of up to 230 nm (PDI < 0.2) containing up to 592 ± 22 μg of dioxadet per mg of polymer nanoparticles were prepared. Study of the drug’s release in a model medium revealed the release up to 64% and 46% of the drug after 8 days for mPEG-b-PLA and mPEG-b-PCL, respectively. Deep analysis of the release mechanisms was carried out with the use of a number of mathematical models. The developed nanoparticles were non-toxic towards both normal (CHO-K1) and cancer (A2780 and SK-OV-3) ovarian cells. A cell cycle study revealed lesser toxicity of nanomedicines towards normal cells and increased toxicity towards cancer cells. The IC50 values determined for dioxadet nanoformulations were in the range of 0.47−4.98 μg/mL for cancer cells, which is close to the free drug’s efficacy (2.60−4.14 μg/mL). The highest cytotoxic effect was found for dioxadet loaded to mPEG-b-PCL nanoparticles.

Ultrasound targeting of microbubble-bound anti PD-L1 mAb to enhance anti-tumor effect of cisplatin in cervical cancer xenografts treatment

AIMS

Anti-PD-L1 monoclonal antibody (mAb)-conjugated ultrasound (US) lipid-shelled microbubbles (PD-L1-MBs) were successfully synthesized to investigate whether that PD-L1-MBs could enhance anti-tumor effect in combination therapy with cisplatin (CDDP) under ultrasound mediation.

MAIN METHODS

Based on affinity between biotin and streptavidin, we prepared microbubbles conjugated with anti-PD-L1 mAb by membrane hydration and mechanical oscillation. A subcutaneous tumor model was established to test the anti-tumor effect and immunological activity of this combination therapy. Bax and Bcl-2 expression were detected by RT-qPCR and Immunohistochemistry. Cells undergoing apoptosis in tissue section were determined by TUNEL. Proliferation of splenocytes was analyzed by Flow cytometry. A cytotoxic T lymphocyte assay was performed by CTL. Expression of PD-L1 and CD8 in tissue section was examined by immunologfluorescence. Expression of IFN-γ, TNF-α, CD86 and CD80 was also detected by RT-qPCR.

KEY FINDINGS

We observed that the growth of the subcutaneous tumor was significantly slower in combined group than that in the group treated with either drug or microbubbles. Moreover, higher antitumor activity was observed in the combined group than that in cisplatin alone, which could be reflected by the number of apoptotic cells in tumor tissues and over expression of bax in the combined group. This combination treatment also exhibited a better immunological activity, increasing the infiltration of CD8⁺ T cells and the expression of several revelant cytokines.

SIGNIFICANCE

The ultrasound lipid-shelled PD-L1-MBs may enhance anti-tumor effects of cisplatin by blocking the PD-L1 site and improving immune function.

Efficacy of a topical gabapentin gel in a cisplatin paradigm of chemotherapy-induced peripheral neuropathy

BACKGROUND

Chemotherapy induced peripheral neuropathy (CIPN) has been attributed to chemotherapeutic agents such as cisplatin which adversely affect disease outcome leading to increased cancer related morbidity. The clinical efficacy of systemic gabapentin in neuropathic pain management is limited by central side-effects in addition to a scarceness of conclusive evidence of its efficacy in CIPN management. The topical route therefore may provide a relatively safe alternative for neuropathic pain treatment in general and CIPN in particular.

METHODS

Cisplatin induced neuropathic nociception was established in rats after a single weekly cisplatin injection (3.0 mg/kg, intraperitoneally) for 4 weeks. The evoked neuropathic sensation of allodynia was assessed by plantar application of von Frey monofilaments as the paw withdrawal threshold (PWT), whereas the expression of heat-hypoalgesia was determined on a hot-plate as paw withdrawal latency (PWL). Gabapentin gel (10% w/w) was applied three-times daily on the hind paws while in a concurrent systemic study, gabapentin was administered daily (75 mg/kg, intraperitoneally) for 4 weeks. To assess any evidence of neurological adverse symptoms of cisplatin and the central side-effect propensity of systemic or topical gabapentin, evaluation of motor coordination (rotarod test) and gait (footprint analysis) were performed.

RESULTS

Cisplatin invoked a progressive development of neuropathic hind paw allodynia (decreased PWT, days 7-28) and heat hypoalgesia (increased PWL, days 21-28). Topical gabapentin significantly delayed the expression of both allodynia on protocol days 21 and 28 and heat-hypoalgesia (day 28). Systemic gabapentin displayed a comparative anti-neuropathic predisposition through a sustained suppression of tactile allodynia on days 14 and 21-28 as well as thermal hypoalgesia (days 21 and 28). Systemic gabapentin also impaired motor coordination and gait thus affirming its clinically documented central side effects, but these outcomes were not evident after topical treatment.

CONCLUSIONS

Both topical and systemic gabapentin exhibit a propensity to attenuate CIPN in a cisplatin paradigm. Gabapentin applied topically may therefore provide an adjunctive or alternative route for CIPN management upon cessation of systemic medications due to intolerable side-effects.

Morphological changes in the ovarian carcinoma cells of Wistar rats induced by chemotherapy with cisplatin and dioxadet

The development of new express methods for the analysis of the efficacy of anti-cancer therapy on the cellular level is highly desirable for the analysis of chemotherapeutic agent performance. In this paper we suggest the use of parameters of cell morphology determined by holographic microscopy and tomography for the effective label free quantitative analysis of cell viability under antitumor chemotherapy and thus of cytostatic agent efficacy. As shown, measured phase shifts and cell morphology change dramatically as a result of chemotherapy and depend strongly on the cell type and agent applied. Experimentally, a comparative analysis of the antitumor efficacy of the two cytostatics, cisplatin and dioxadet, that are commonly used for chemotherapy of disseminated ovarian carcinoma has been performed. The experiments were carried out on the Wistar rat model. An essential difference in the morphology of cells, both normal (erythrocytes) and cancerous, present in ascitic fluid taken from the non-treated group of rats and the groups treated with either dioxadet or cisplatin, has been observed. The results obtained can be interpreted as an indication of the antitumor performance of both cytostatics at the cellular level and as a demonstration of the higher efficacy of therapy with dioxadet as compared to that with cisplatin. Differences in cell morphology are suggested to be applied as quantitative markers of cell viability and cytostatic agent efficacy. The conclusions made are supported by a comparison with the results of recent experiments based on survival rates of laboratory animals treated with these agents..

In vivo effects of dexmedetomidine on immune function and tumor growth in rats with ovarian cancer through inhibiting the p38MAPK/NF-κB signaling pathway

OBJECTIVES

During this study, we aimed to analyze the correlation between dosages of dexmedetomidine (DEX) and the p38MAPK/NF-κB signaling pathway, and their effects on immune function and tumor growth in rats with ovarian cancer (OC).

METHODS

A total of 100 rats were selected for the purposes of the study. The normal group consisted of 20 rats, while the remaining 80 rats were utilized for OC model establishment purposes, and further assigned into the model, 0.2 DEX, 1 DEX and 5 DEX groups (based on respective dosages of DEX, n=20 per group). The tumor inhibition rate was calculated. Positive expressions of p38 and NF-κB in ovarian tissues were examined by means of immunohistochemical staining. Cell transformation as well as lymphocyte proliferation rates were measured using MTT. Cell cycle and apoptosis of CD4+ and CD8+ cells were determined by flow cytometry. Serum levels of IL-2 and TNF-α were detected using ELISA, while qRT-PCR and western blotting methods were used to analyze mRNA and protein expressions of p38 and NF-κB.

RESULTS

Compared with the normal group, the other four groups exhibited up-regulated IL-2, TNF-α serum levels as well as up regulated expressions of p38, NF-κB65 mRNA and protein; while the respective percentages of both CD4+ and CD8+ T cells exhibited down-regulated rates. The other four groups displayed increases in tumor weight and cell apoptosis, as well as decreased levels of cell proliferation and transformation rates. The aforementioned findings of the study ultimately highlighted a greater tendency among the three DEX groups in comparison to the model group.

CONCLUSION

The findings of the study suggest that a particular dosage of DEX may act to enhance the immune function of rats with OC by inhibiting the p38MAPK/NF-κB signaling pathway.

Comparative efficacy evaluation of catheter intraperitoneal chemotherapy, normothermic and hyperthermic chemoperfusion in a rat model of ascitic ovarian cancer

OBJECTIVES

The choice of an optimal administration route for intraperitoneal (IP) chemotherapy and a suitable chemotherapeutic regime in the treatment of ovarian cancer remains a controversy. We investigated survival outcomes according to catheter intraperitoneal chemotherapy (CIPC), normothermic and hyperthermic chemoperfusion (NIPEC and HIPEC) with cytostatic drugs dioxadet and cisplatin in rats with transplantable ascitic ovarian cancer.

METHODS

Ascitic liquid containing 1 × 10⁷ tumour cells was inoculated to female Wistar rats and 48 hours after rats received dioxadet and cisplatin at the maximum tolerated doses. Dioxadet at doses 1.5, 30 and 15 mg/kg and cisplatin at doses 4, 40 and 20 mg/kg body weight were administered for CIPC, NIPEC and HIPEC, respectively. Rats in the control groups received physiological saline and CIPC with physiological saline was regarded as the untreated control. The antitumor activity of the drugs was evaluated as an increase in average life expectancy (ALE). Analysis of the data was based primarily on Bayesian statistics and included Kaplan-Meier method, log-rank test and hazard ratio (HR) estimation.

RESULTS

Compared to the untreated control CIPC, NIPEC and HIPEC with dioxadet significantly increased ALE by ₁₀13₁₆, ₆15₂₄ and _1.717₃₅ days, whereas with cisplatin by ₆10₁₃, ₁₂24₃₇ and _-135₂₃ days, respectively.

CONCLUSIONS

Dioxadet and cisplatin show similar efficacy in the CIPC route. Compared with CIPC IP chemotherapy by chemoperfusions is more effective for both the drugs. Dioxadet in HIPEC showed highest survival benefit whereas largest effect during NIPEC is achieved with cisplatin.