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Tumor hypoxia is a hallmark of solid tumors and emerged as the therapeutic target for cancer treatments, such as a prodrug Tirapazamine (TPZ) activated in hypoxia. To increase tumor accumulation, gold nanoparticles (GNPs) were selected to conjugate with TPZ. In this study, we successfully formulated and assessed the biochemical and therapeutic roles of the conjugated gold nanoparticles–Tirapazamine (GNPs–TPZ) on therapeutic assessments of MKN45-induced xenograft animal model. The results indicated that GNPs–TPZ was a potential nanomedicine for selectively targeting hypoxia tumors coupled with decreased side effects on healthy tissue or organs. TPZ significantly reduced cell viability of hypoxic gastric cancer MKN45 cells, but not in cells incubated in normoxia condition. For improving tumor targeting efficiency, furthermore, the GNPs drug carrier was conjugated to TPZ via biding mediator bovine serum albumin (BSA), and we demonstrated that this conjugated GNPs–TPZ retained the unique characteristics of hypoxic toxin and possessed the adequate feature of systemic bio-distributions in animals. GNPs–TPZ nanoparticles revealed their superior affinity to hypoxia tumors in the MKN45 xenograft. Moreover, GNPs–TPZ treatments did not significantly alter the biochemical parameters of blood samples acquired from animals. Taken together, TPZ, a prodrug activated by hypoxia, was conjugated with GNPs, whereas BSA severed as an excellent binding agent for preparing the conjugated GNPs–TPZ nanomedicines. We demonstrated that GNPs–TPZ enhanced tumor targeting, resulting in higher therapeutic efficacy compared to TPZ. We suggest that it may sever as an adjuvant treatment or combined therapy with other chemotherapeutics for the treatment of cancer patients in the future.

Cisplatin is one of the most common therapeutics used in treatments of several types of cancers. To enhance cisplatin lipophilicity and reduce resistance and side effects, a polyfluorinated bipyridine-modified cisplatin analogue, dichloro[4,4’-bis(2,2,3,3-tetrafluoropropoxy)methyl)-2,2’-bipryridine] platinum (TFBPC), was synthesized and therapeutic assessments were performed. TFBPC displayed superior effects in inhibiting the proliferation of several cisplatin-resistant human cancer cell lines, including MDA-MB-231 breast cancers, COLO205 colon cancers and SK-OV-3 ovarian cancers. TFBPC bound to DNA and formed DNA crosslinks that resulted in DNA degradation, triggering the cell death program through the PARP/Bax/Bcl-2 apoptosis and LC3-related autophagy pathway. Moreover, TFBPC significantly inhibited tumor growth in both animal models which include a cell line-derived xenograft model (CDX) of cisplatin-resistant MDA-MB-231, and a patient-derived xenograft (PDX) model of triple-negative breast cancers (TNBCs). Furthermore, the biopsy specimen from TFBPC-treated xenografts revealed decreased expressions of P53, Ki-67 and PD-L1 coupled with higher expression of cleaved caspase 3, suggesting TFBPC treatment was effective and resulted in good prognostic indications. No significant pathological changes were observed in hematological and biochemistry tests in blood and histological examinations from the specimen of major organs. Therefore, TFBPC is a potential candidate for treatments of patients suffering from TNBCs as well as other cisplatin-resistant cancers.

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