A comparative study of the cytogenetic and antineoplasmatic effects induced by carboplatin in combination with niacin in human lymphocytes in vitro and in Ehrlich ascites tumor cells in vivo

Genotoxicity of cisplatin and carboplatin in cultured human lymphocytes: a comparative study

Cisplatin and carboplatin are integral parts of many antineoplastic management regimens. Both platinum analogues are potent DNA alkylating agents that robustly induce genomic instability and promote apoptosis in tumor cells. Although the mechanism of action of both drugs is similar, cisplatin appears to be more cytotoxic. In this study, the genotoxic potential of cisplatin and carboplatin was compared using chromosomal aberrations (CAs) and sister-chromatid exchange (SCE) assays in cultured human lymphocytes. Results showed that cisplatin and carboplatin induced a significant increase in CAs and SCEs compared to the control group (p<0.01). Levels of induced CAs were similar in both drugs; however, the magnitude of SCEs induced by cisplatin was significantly higher than that induced by carboplatin (p<0.01). With respect to the mitotic and proliferative indices, both cisplatin and carboplatin significantly decreased mitotic index (p<0.01) without affecting the proliferative index (p>0.05). In conclusion, cisplatin was found to be more genotoxic than carboplatin in the SCE assay in cultured human lymphocytes, and that might explain the higher cytotoxicity of cisplatin.

Biological relevance of CuFeO2 nanoparticles: Antibacterial and anti-inflammatory activity, genotoxicity, DNA and protein interactions

Heterometal oxide nanoparticles of bioessential metals are shedding new light to nanoparticle-inspired bioapplications. Pairing bioreactive elements like copper and iron can affect the redox dynamic and biological profile of the nanomaterial. Given the complexity of physicochemical properties, biological activity and toxicity concerns, extensive exploration is demanded, especially when active and less active oxidation states participate as in case of cuprous-ferric delafossite CuFeO₂ (copper(I)-iron(III)), a less widespread nanomaterial. In that vein, CuFeO₂ nanoparticles were synthesized and biological profile was evaluated in comparison with cuprous oxide (Cu₂O NPs) counterpart, an already established antimicrobial agent. Interactions with bacteria, proteins and DNA were examined. Cu₂O NPs exhibited stronger antibacterial activity (IC₅₀ < 25 μg/ml) than CuFeO₂ NPs (IC₅₀ > 100 μg/ml). In vitro exposure of nanoparticles on plasmid DNA unveiled toxicity in the form of DNA damage for Cu₂O and enhanced biocompatibility for CuFeO₂ NPs. Genotoxicity estimated by the frequency of sister chromatid exchanges, cytostaticity based on the proliferating rate indices and cytotoxicity based on the mitotic indices at human peripheral lymphocyte cultures were all significantly lower in the case of CuFeO₂ NPs. Furthermore, through in vitro albumin denaturation assay, CuFeO₂ NPs showed better performance in protein denaturation protection, correlating in superior anti-inflammatory activity than Cu₂O and similar to acetylsalicylic acid. Synergy of copper(I)-iron(III) in nanoscale is apparent and gives rise to fruitful bioapplications and perspectives.

Sister chromatid exchange assay as a predictor of tumor chemoresponse

Sister Chromatid Exchanges (SCEs) are known to enhance as a consequence of exposure to various mutagenic agents and appear to indicate DNA damaging effects and/or subsequent repair by homologous recombination (HR). DNA damage plays an interesting role in the majority of mechanisms underlying the effects of antitumor drugs, since the genetic activity of the plethora of these agents is due to their ability to damage the DNA. The DNA-effects of antitumor agents towards normal cells (genotoxicity) are great drawbacks of antitumor therapy and are connected to important adverse health effects in cancer patients undergoing chemotherapy. On the other hand, failure of chemotherapy in many cases is due to the DNA repair ability which cancer, like normal cells, also possess. As both DNA repair and genotoxic exposure are expected to vary among patients, correlating SCEs frequencies with only individual repair capacity may be feasible to predict. Cancer risk has not been observed to be associated with high SCEs levels. Since the administration of effective antitumor drugs with limited adverse effects is of great importance in the success of anticancer therapy, a lot of interest has been directed toward the development of methods and approaches that would enable the correct selection of appropriate drugs prior to the initiation of therapy on an individual basis. To this effect, more than 30 years ago, an investigation of the ability of the in vitro and the in vivo SCEs-assay to predict the in vitro and in vivo sensitivity of tumor cells to newly synthesized drugs or to those already in use began. In this short review a critical appraisal of the SCEs-assay as an important biomarker used for predicting cancer chemo-response as well as a summary of the key findings from several studies published within the last 20 years in this field is performed.

In vivo synergistic cytogenetic effects of aminophylline on lymphocyte cultures from patients with lung cancer undergoing chemotherapy

BACKGROUND

The anti-cancer and cytogenetic effects of aminophylline (AM) have been demonstrated in several clinical trials. The aim of the present study was to investigate the in vivo cytogenetic effects of AM in newly diagnosed patients with small cell (SCLC) and non-small cell lung cancer (NSCLC), receiving chemotherapy for the first time.

METHODS

Sister chromatid exchanges (SCEs) and proliferation rate index (PRI) were evaluated in peripheral blood lymphocyte cultures from six patients with SCLC and six patients with NSCLC after the in vitro addition of AM and after the in vivo administration of AM in patients receiving chemotherapy.

RESULTS

The in vitro addition of AM significantly increased SCEs only in SCLC patients (p<0.001). The in vivo administration of AM after chemotherapy increased SCEs in both cancer types (SCLC: p<0.001, NSCLC: p=0.003) and this increase was synergistic, the rates of SCEs in the presence of AM were higher than the expected SCE values if the increases above background for chemotherapy and AM were independent and additive (SCLC: p<0.001, NSCLC: p=0.008). Although in both groups of patients cell division delays were observed after the combined chemotherapy plus in vivo AM treatment, the correlation between the magnitude of the SCE response and the PRI depression was not statistically significant (p>0.05).

CONCLUSIONS

These observations suggest that AM enhances the results of concurrently administered chemotherapy by synergistically increasing its cytogenetic effects in patients with lung cancer.

A new approach for evaluating in vivo anti-leukemic activity using the SCE assay. An application on three newly synthesised anti-tumour steroidal esters

Three newly synthesised steroidal esteric derivatives of nitrogen mustard (compounds 1-3) were comparatively studied on a molar basis regarding their ability to induce sister chromatid exchanges (SCEs) in normal human lymphocytes in vitro and therapeutic effects on leukemia P388 bearing mice. Compounds 1 and 3 are modified steroidal esters of p-methyl-m-N,N-bis(2-chloroethyl)amino benzoic acid, and compound 2 is a modified steroidal ester of chlorambucil. All compounds induced statistically significant increases in SCEs and decreases in proliferation rate indices (PRIs) of cultured human lymphocytes and significantly increased the life span of P388 bearing mice. In this study, the doses applied for therapeutic purposes upon leukemia P388 bearing mice in vivo were derived from cytogenetic observations in normal human lymphocytes in vitro. A substantially better therapeutic effect was obtained compared to the effect achieved after the use of quite higher doses related with LD(10) values. We have demonstrated that the order of anti-tumour effectiveness of the treatment schedules of the three newly synthesised compounds tested (at doses derived from cytogenetic observations) coincides with the order of the cytogenetic effects they induce. The SCE assay appears to have an application in the clinical prediction of tumour sensitivity to potential chemotherapeutics.

7-Keto hybrid steroidal esters of nitrogen mustard: cytogenetic and antineoplastic effects

Four newly synthesized antitumor steroidal compounds were compared, on a molar basis, regarding their ability to induce sister chromatid exchanges (SCEs) and cell division delays. The concept of designing and developing these compounds (1-4) is to enhance the anticancer activity of esteric steroidal derivatives of nitrogen mustard by introduction of a keto group at the 7-position of the D5 steroidal skeleton, and a double bond between positions 6 and 7 of the B ring of the steroidal nucleus. In our study, the cytogenetic and antileukemic effects of these newly synthesized compounds are reported. The four substances induced statistically significant enhancement of SCEs and of cell division delays, and in both schedules used, therapeutic effects. However, compounds 1 and 3 showed increased genotoxicity towards human lymphocytes (p<0.001) and antileukemic activity towards P388 leukemias (p<0.001), compared to compounds 2 and 4. It seems that the introduction of a keto group at the 7-position of the steroidal skeleton enhances the antitumor effect of these substances in comparison with our previous studies with the corresponding compounds characterized by the absence of the 7-keto group. Therefore, the in vivo antitumor effect of the four compounds appears to correlate well with the in vitro cytogenetic effect caused by these chemicals.