Doxorubicin-transferrin conjugate selectively overcomes multidrug resistance in leukaemia cells

Abstract

Neoplastic cells frequently have an increased number of transferrin receptors. Coupling transferrin to an anti-neoplastic drug has the potential to overcome multidrug resistance (MDR). The purpose of this study was to examine the distribution and action of doxorubicin-transferrin conjugate (DOX-TRF) in a leukaemia cell line (HL60), a multidrug-resistant leukaemia cell line (HL60ADR) and a normal tissue cell line (human fibroblasts). The intracellular accumulation of DOX and DOX-TRF was monitored by direct fluorescence. More DOX-TRF than free DOX was delivered to the tumour cells, and consecutively the levels of DNA double-strand breaks and apoptosis increased even in the multidrug-resistant cell line. In the normal tissue cell line, DOX-TRF did not accumulate, and therefore, the levels of DNA double-strand breaks and apoptosis did not increase. Cell viability was determined using the MTT assay. The IC 50 for DOX-TRF was lower than the IC 50 value for the free drug in both leukaemia cell lines. The IC 50 values for the HL60 cells were 0.08 µM for DOX and 0.02 µM for DOX-TRF. The IC 50 values for HL60ADR cells were 7 µM for DOX and 0.035 µM for DOX-TRF. In conclusion, DOX-TRF was able to overcome MDR in the leukaemia cell lines while having only a very limited effect on normal tissue cells.

The transferrin receptor and the targeted delivery of therapeutic agents against cancer

“…The protein conjugate was shown not to translocate to the nucleus, but to act on various enzymes within the plasma membrane, suggesting that the action of ADR was directed by the physiological interactions of Tf [26, 27, 31]. Importantly, this conjugate was also able to overcome multidrug resistance while minimizing toxicity to normal cells [28, 32, 33]. …”

Anthracycline nano-delivery systems to overcome multiple drug resistance: A comprehensive review

“…The increased cytotoxicity of transferrin-DOX conjugate over that of free DOX was partly explained by the conjugate bio-reductive processes and ROS generation in cytoplasma. The ability of the transferrin-DOX conjugate to overcome MDR was further confirmed by Łubgan, where the conjugate was 4- and 200-fold more cytotoxic than free DOX in sensitive HL-60 and resistant HL-60/ADR leukemia cells, respectively [111]. Interestingly, when Munns et al investigated transferrin-DOX conjugate in sensitive MGH-U1 and resistant MGH-U1R bladder cancer cell lines, it was found that the conjugate did not overcome resistance [112].…”

Toxicity of doxorubicin-transferrin conjugate is connected to the modulation of Wnt/β-catenin pathway in human leukemia cells

“…Based on the cytotoxicity MTT-Assay, Lubgan et al [24] found that respective DOX and DOX-TRF IC 50 values for HL60 cells were 0.08 μM and 0.02 μM, whereas 7 μM doxorubicin and 0.035 μM DOX-TRF were required to cause 50% growth inhibition in the doxorubicin-resistant cell line. Moreover, studies performed by Fritzer et al proved that in highly multidrug resistant KB-C1 and KB-V1 cells, DOX up to 1 μM did not cause any cytotoxic effects, while the DOX-TRF conjugate inhibited the colony formation of these cells with IC 50 levels of 0.2 and 0.025 μM, respectively [33] As shown in Fig.…”

“…DOX-TRF conjugate was synthesized and analyzed according to the modified procedure [23,24] presented in our previous work [21]. For carrying out the conjugation procedure, human transferrin, glutaraldehyde and ethanolamine were supplied from Sigma (Darmstadt, Germany).…”