Aminooxyacetic acid (AOAA) sensitizes colon cancer cells to oxaliplatin via exaggerating apoptosis induced by ROS

Abstract

Background: As the third confirmed gaseous transmitter, the role of hydrogen sulfide (H2S) in the pathogenesis of multiple types of cancer has been attracting increasing attention. Increased expression of cystathionine β-synthase (CBS) and H2S in colon cancer tissue samples has been validated and tumor-derived H2S, mainly produced by CBS, stimulates bioenergetics, cell proliferation, and angiogenesis in colon cancer. Recently, the therapeutic manipulation of H2S has been proposed as a promising anticancer approach. However, the effect of aminooxyacetic acid (AOAA), which has been widely used as an inhibitor of CBS dependent synthesis of H2S, on the chemotherapeutic effect of oxaliplatin (OXA) and the underlying mechanisms remain to be illustrated. Methods: We examined the expression of CBS in human colorectal cancer specimens and matched normal mucosa by immunohistochemistry. The effect of AOAA on the sensitivity of colon cancer cells to OXA and the level of apoptosis induced by caspase cascade was investigated in both HCT116 and HT29 cell lines utilizing CCK-8 assays, flow cytometry analysis and western blot analysis. The endogenous levels of reactive oxygen species (ROS) were detected fluorescently by DCF-DA, and glutathione (GSH) levels were measured by a Total GSH Detection Kit. Tumor bearing xenograft mouse models and in vivo imaging systems were further used to investigate the effect of AOAA in vivo and immunohistochemistry (IHC) and TUNEL analysis were performed. Results: In the current study, we confirmed CBS, the main target of AOAA, is overexpressed in human colorectal cancer by immunohistochemistry. The inhibitory effect of AOAA on the synthesis of H2S was validated utilizing fluorescent probe and specific electrode. AOAA significantly reduced the IC50 values of OXA in both colon cancer cell lines. Co-incubation with AOAA elicited increased apoptosis induced by OXA, featured by increased activation of caspase cascade. Besides, AOAA further increased the levels of ROS induced by OXA and attenuated the synthesis of glutathione (GSH), which is a vital antioxidant. Besides, the results of in vivo imaging and following IHC and TUNEL analysis were in accordance with cellular experiments, indicating that AOAA sensitizes colon cancer cells to OXA via exaggerating intrinsic apoptosis. Conclusion: The results suggested that CBS is overexpressed in colorectal cancer tissues and AOAA sensitizes colon cancer cells to OXA via exaggerating apoptosis both in vitro and in vivo. Decreasing the endogenous level of GSH and consequently impaired detoxification of ROS might be one of the mechanisms underlying the effect of AOAA.

In vitro anticancer activity of hydrogen sulfide and nitric oxide alongside nickel nanoparticle and novel mutations in their genes in CRC patients

“…The results demonstrated a ten-fold increase in DNA fragmentation in HT-29 cells treated with Na 2 S compared to the untreated cells, while 100% of the cells were killed using 5-FU or co-treatment with Na 2 S and 5-FU. Our finding is in agreement with recently published in vivo work, wherein they demonstrate a significant increase in TUNEL positive cells after inhibition of CBS 36 . Earlier published work has shown CBS to be overexpressed and promote cell proliferation and stimulate angiogenesis in CRC patients 33 .…”

The interaction between ferroptosis and lipid metabolism in cancer

“…154 The transaminase inhibitor aminooxyacetic acid can suppress ferroptosis by targeting mitochondrial fatty-acid synthesis and is employed in preclinical trials for colon cancer treatment. 4,155,156 As mentioned above, ACSL3 is required for inducing the ferroptosis-resistance, while ACSL4 is essential for inducing ferroptosis. 10,47 Hence, ferroptosis inducer combined with ACSL3 inhibitor may lead to a better antitumor efficacy.…”

Role of Hydrogen Sulfide and 3-Mercaptopyruvate Sulfurtransferase in the Regulation of the Endoplasmic Reticulum Stress Response in Hepatocytes

“…For the combined pharmacological inhibition of CBS and CSE, we used aminooxyacetic acid (AOAA), an agent that is commonly referred to as a “CBS inhibitor”, even though in fact it inhibits both CBS and CSE (as well as a host of additional PLP-dependent enzymes) [ 20 , 21 ]. We have utilized the AOAA concentrations of 30 µM and 100 µM, which have been commonly used in prior studies, and in most cell types do not affect baseline cell viability or cell function (although it can sensitize cells to cytotoxic agents) [ 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ]. However, in our HepG2 cells, we have noticed that even at the lowest concentration of AOAA, there is a baseline impairment of cell viability and proliferation ( Figure 11 a,b).…”