Cancer chemotherapy drug cisplatin is known for its nephrotoxicity. The aim of this study is to investigate whether Epigallocatechin 3-Gallate (EGCG) can reduce cisplatin mediated side effect in kidney and to understand its mechanism of protection against tissue injury. We used a well-established 3-day cisplatin induced nephrotoxicity mice model where EGCG were administered. EGCG is a major active compound in Green Tea and have strong anti-oxidant and anti-inflammatory properties. EGCG protected against cisplatin induced renal dysfunction as measured by serum creatinine and blood urea nitrogen (BUN). EGCG improved cisplatin induced kidney structural damages such as tubular dilatation, cast formation, granulovaculoar degeneration and tubular cell necrosis as evident by PAS staining. Cisplatin induced kidney specific mitochondrial oxidative stress, impaired activities of mitochondrial electron transport chain enzyme complexes, impaired anti-oxidant defense enzyme activities such as glutathione peroxidase (GPX) and manganese superoxide dismutase (MnSOD) in mitochondria, inflammation (tumor necrosis factor α and interleukin 1β), increased accumulation of NF-κB in nuclear fraction, p53 induction, and apoptotic cell death (caspase 3 activity and DNA fragmentation). Treatment of mice with EGCG markedly attenuated cisplatin induced mitochondrial oxidative/nitrative stress, mitochondrial damages to electron transport chain activities and antioxidant defense enzyme activities in mitochondria. These mitochondrial modulations by EGCG led to protection mechanism against cisplatin induced inflammation and apoptotic cell death in mice kidney. As a result, EGCG improved renal function in cisplatin mediated kidney damage. In addition to that, EGCG attenuated cisplatin induced apoptotic cell death and mitochondrial reactive oxygen species (ROS) generation in human kidney tubular cell line HK-2. Thus, our data suggest that EGCG may represent new promising adjunct candidate for cisplatin.

Oxidative and nitrative stress is a well-known phenomenon in cisplatin-induced nephrotoxicity. The purpose of this work is to study the role of two metalloporphyrins (FeTMPyP and MnTBAP), water soluble complexes, in cisplatin-induced renal damage and their ability to scavenge peroxynitrite. In cisplatin-induced nephropathy study in mice, renal nitrative stress was evident by the increase in protein nitration. Cisplatin-induced nephrotoxicity was also evident by the histological damage from the loss of the proximal tubular brush border, blebbing of apical membranes, tubular epithelial cell detachment from the basement membrane, or intra-luminal aggregation of cells and proteins and by the increase in blood urea nitrogen and serum creatinine. Cisplatin-induced apoptosis and cell death as shown by Caspase 3 assessments, TUNEL staining and DNA fragmentation Cisplatin-induced nitrative stress, apoptosis and nephrotoxicity were attenuated by both metalloporphyrins. Heme oxygenase (HO-1) also plays a critical role in metalloporphyrin-mediated protection of cisplatin-induced nephrotoxicity. It is evident that nitrative stress plays a critical role in cisplatin-induced nephrotoxicity in mice. Our data suggest that peroxynitrite is involved, at least in part, in cisplatin-induced nephrotoxicity and protein nitration and cisplatin-induced nephrotoxicity can be prevented with the use of metalloporphyrins.

Oxidative stress and inflammation are part and parcel of cisplatin-induced nephrotoxicity. The purpose of this work is to study the role of soy isoflavone constituent, daidzein, in cisplatin-induced renal damage. Cisplatin-induced nephrotoxicity was evident by the histological damage in proximal tubular cells and by the increase in serum neutrophil gelatinase-associated lipocalin (NGAL), blood urea nitrogen (BUN), creatinine, and urinary kidney injury molecule-1 (KIM-1). Cisplatin-induced cell death was shown by TUNEL staining and caspase-3/7 activity. Daidzin treatment reduced all kidney injury markers (NGAL, BUN, creatinine, and KIM-1) and attenuated cell death (apoptotic markers). In cisplatin-induced kidney injury, renal oxidative/nitrative stress was manifested by the increase in lipid peroxidation and protein nitration. Cisplatin induced the reactive oxygen species-generating enzyme NOX-2 and impaired antioxidant defense enzyme activities such as glutathione peroxidase (GPX) and superoxide dismutase (SOD) activities. Cisplatin-induced oxidative/nitrative stress was attenuated by daidzein treatment. Cisplatin induced CD11b-positive macrophages in kidneys and daidzein attenuated CD11b-positive cells. Daidzein attenuated cisplatin-induced inflammatory cytokines tumor necrosis factor α (TNFα), interleukin 10 (IL-10), interleukin 18 (IL-18), and monocyte chemoattractant protein-1 (MCP-1). Daidzein attenuated cell death in vitro. Our data suggested that daidzein attenuated cisplatin-induced kidney injury through the downregulation of oxidative/nitrative stress, immune cells, inflammatory cytokines, and apoptotic cell death, thus improving kidney regeneration.

Glucose-6-phosphate dehydrogenase (G6PD) is a rate-limiting enzyme of the pentose phosphate pathway. Multiple studies have previously revealed that elevated G6PD levels promote cancer progression in numerous tumor types; however, the underlying mechanism remains unclear. In the present study, it was demonstrated that high G6PD expression is a poor prognostic factor in bladder cancer, and the levels of G6PD expression increase with increasing tumor stage. Patients with bladder cancer with high G6PD expression had worse survival rates compared with those with lower G6PD expression in resected tumors. In vitro experiments revealed that knockdown of G6PD suppressed cell viability and growth in Cell Counting Kit-8 and colony formation assays, and increased apoptosis in bladder cancer cell lines compared with normal cells. Further experiments indicated that the weakening of the survival ability in G6PD-knockdown bladder cancer cells may be explained by intracellular reactive oxygen species accumulation and protein kinase B pathway suppression. Furthermore, it was additionally revealed that 6-aminonicotinamide (6-AN), a competitive G6PD inhibitor, may be a potential therapy for bladder cancer, particularly in cases with high G6PD expression, and that the combination of cisplatin and 6-AN may optimize the clinical dose or minimize the side effects of cisplatin.

Mitochondrial GTPase mitofusin-2 gene (Mfn2) is a novel gene characterised as a cell proliferation inhibitor. Mfn2 protein over-expression, mediated by an adenovirus, has a significant anti-tumour effect in A548 and HT-29 cells. However, there is no report on the effect of Mfn2 on urinary bladder carcinoma (UBCC). In this study, we sought to investigate the function of Mfn2 in UBCC. Mfn2 expression in 36 paired UBCC samples was investigated by reverse transcription-polymerase chain reaction and Western blot analyses. An adenovirus encoding the complete Mfn2 open reading frame (Ad-Mfn2) was used to infect UBCC cells, and an adenoviral vector encoding green fluorescent protein (Ad-GFP) was used as a control. The effects of Mfn2 on cell-cycle distribution and apoptosis were assessed by flow cytometry and Western blot analyses. The Mfn2 protein showed significantly lower expression in UBCC tissues than nearby non-tumourous tissues. Ad-Mfn2 exhibited a significant anti-tumour effect in T24 and 5,637 cells. Mfn2 overexpression in T24 cells significantly inhibited cell proliferation, by arresting the transition of the cell cycle from the G(1) to S phase, and induced apoptosis by upregulating active caspase-3 and cleaved PARP levels. Mfn2 also induced increased p21 and p27 expression levels, but down-regulated PCNA levels. These findings indicate that Mfn2 is a potential UBCC tumour suppressor gene, which showed significantly lower expression in tumour tissues than adjacent non-tumourous tissues and could promote apoptosis and inhibit the proliferation of UBCC cells. Mfn2 may become an important therapeutic target for treating UBCC.