HAMNO (NSC-111847) is a protein interaction inhibitor of replication protein A (RPA).

RPA:

HAMNO在两种HNSCC细胞系中抑制集落形成。HAMNO与依托泊苷结合显著地更大程度地抑制集落形成，超过了HAMNO单独使用的效果。在UMSCC38细胞中，HAMNO剂量依赖性地增加了全核γ-H2AX染色的发生。UMSCC38和UMSCC11B细胞在与HAMNO（20 μM）孵育后，显示出显著的γ-H2AX染色。在UMSCC38和OKF4细胞中，HAMNO增加了γ-H2AX染色，且在S期信号增加最多。

在小鼠体内，HAMNO抑制UMSCC11B肿瘤的进展。经过etoposide（20 μM，2小时）处理后，RPA32的Ser33（一个ATR底物）高度磷酸化，而添加2 μM HAMNO后这种磷酸化现象有所减少，在更高浓度下几乎消失，这证明HAMNO可以抑制ATR对RPA32的磷酸化。

Cell cycle assessment and γ-H2AX staining are monitored in UMSCC38 and OKF4 cells after 2 h incubation with HAMNO (2, 20, 50 μM) and fixed in 70% ethanol overnight. Cells are washed with PBS and incubated overnight in PBS containing 1% BSA, 10% goat serum, and PS139-H2AX antibodies washed and incubated in goat anti-mouse Alexa Fluor 647 antibody for 30 min at room temperature. Cells are incubated in 50 μg/mL propidium iodide and 100 μg/mL RNase A for 30 min, and 10,000 cells per sample are analyzed.

UMSCC38 and UMSCC11B cells are implanted into 6-week-old female mice by a single subcutaneous injection of tumor cells (2 to 6×105 cells in 100 mL of sterile PBS). The growth rates of tumors are determined by daily monitoring of tumor volume with vernier calipers [tumor volume=1/2(length×width2)]. Once the tumor size reaches 50 mm3, etoposide (10 mg/kg mouse) and HAMNO (2 mg/kg) are administered intraperitoneally every day for 3 days. Tumor size is monitored daily and the volume of the tumor is compared among all experimental groups.