Journal: Cancers

Article Title: Regulation of PD-L1 Expression by SAHA-Mediated Histone Deacetylase Inhibition in Lung Cancer Cells

doi: 10.3390/cancers17172919

Figure Lengend Snippet: Mechanisms of PD-L1 regulation in lung cancer. PD-L1 expression in tumor cells is regulated at multiple levels. The p53–p21 axis can negatively influence PD-L1 transcription, while oncogenic pathways such as PI3K/AKT and JAK/STAT promote its up-regulation. Epigenetic mechanisms play a critical role: histone acetylation and methylation dynamically regulate chromatin accessibility, and DNA methylation (e.g., via DNMT1) can repress or activate PD-L1 transcription depending on context. Collectively, these mechanisms contribute to PD-L1-mediated immune evasion and tumor survival.

Article Snippet: pp53 (Phospho-p53) , CST , 12571 , 1:1000.

Techniques: Expressing, Methylation, DNA Methylation Assay

Journal: iScience

Article Title: IMPDH inhibition induces DNA replication stress and ATR sensitivity in Merkel cell carcinoma

doi: 10.1016/j.isci.2025.112567

Figure Lengend Snippet: MCC cell lines are highly sensitive to IMPDH inhibition (A) CellTiter-Glo viability assay of established MCCP cell lines treated with increasing dosages of MPA for 3 days. Line color identifies p53-wild type (blue) and p53-mutant (red) cell lines. Statistics represent lowest significance (highest p ) of any p53-wild type versus mutant comparisons at the specified dose. N = 3; mean ± SD; two-way ordinary ANOVA corrected for multiple comparisons via Tukey post hoc test; ∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001, ∗∗∗∗ p < 0.0001. The IC 50 was calculated for each cell line. (B) CellTiter-Glo viability assay of WaGa and MKL-1 cell lines treated concurrently with MPA (1 μM) and guanosine (10 μM) for 3 days. N = 3; mean ± SD; two-way ordinary ANOVA corrected for multiple comparisons via Tukey post hoc test; ∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001, ∗∗∗∗ p < 0.0001. (C) CellTiter-Glo viability assay of PDCLs treated as in (A), with an additional dose of MPA (50 μM). Line coloring and statistical test are identical to (A); N = 3; mean ± SD. The IC 50 was calculated for each cell line. (D) CellTiter-Glo viability assay of PDCLs treated concurrently with MPA (5 μM) and guanosine (1 μM) for 3 days. N = 3; mean ± SD; statistical tests are identical to (B). (E) Immunoblot of WaGa cells treated with MPA (1 μM) and guanosine (10 μM) for 24 h. Representative of 3 independent experiments. (F) Immunoblot of MKL-1 cells treated with MPA (1 μM) and guanosine (10 μM) for 3 days. Representative of 3 independent experiments. For panels E and F, total p53 is a reblot of the pp53 blot after stripping (see ) and p21 is a reblot of PUMA. (G) RT-qPCR analysis of p53-dependent gene activation in WaGa and MKL-1 cells treated with MPA (1 μM) and guanosine (10 μM) for 1 or 3 days, respectively. Genes were normalized to the geometric mean of β-actin and β-2-microglobulin via the ΔΔCt method. N = 3; mean ± SD; one-way ordinary ANOVA corrected for multiple comparisons via Tukey post hoc test; ∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001, ∗∗∗∗ p < 0.0001. (H) AV/PI staining of WaGa cells treated with MPA (1 μM) and guanosine (10 μM) for 2 days. N = 3; mean ± SD; statistical tests are identical to (G). See also G and S1H.

Article Snippet: pp53 (Ser15) , Cell Signaling Technology , CAT# 9284; RRID: AB_331464.

Techniques: Inhibition, Viability Assay, Mutagenesis, Western Blot, Stripping Membranes, Quantitative RT-PCR, Activation Assay, Staining

Journal: iScience

Article Title: IMPDH inhibition induces DNA replication stress and ATR sensitivity in Merkel cell carcinoma

doi: 10.1016/j.isci.2025.112567

Figure Lengend Snippet: Functional p53 enhances IMPDH inhibition-induced cytotoxicity but is not required for cytotoxicity in MCC (A) Immunoblot of WaGa cells with inducible dominant negative p53 (p53DD) or eGFP pretreated with DOX (1 μg/mL) for 24 h followed by MPA (1 μM) for an additional 24 h. Representative of 3 independent experiments. (B) Immunoblot of MKL-1 clonal p53 knockout (KO) or control (AANSV1 and NTC) cells treated with MPA (1 μM) for 3 days. Representative of 3 independent experiments. For panels A and B, total p53 is a reblot of pp53 and p21 is a reblot of PUMA. (C) CellTiter-Glo viability assay of WaGa cells pretreated with DOX (1 μg/mL) for 24 h followed by MPA (1 μM) for 3 days. N = 3; mean ± SD; two-way ordinary ANOVA corrected for multiple comparisons via Tukey post hoc test; ∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001, ∗∗∗∗ p < 0.0001. (D) AV/DAPI staining of WaGa cells treated as in (C) for 2 days. N = 3; mean ± SD; statistical tests are identical to (C). See also B and S2C. (E) CellTiter-Glo viability of clonal MKL-1 control and p53 KO cell lines treated with increasing dosages of MPA for 3 days. N = 3; mean ± SD. Statistical tests are identical to (C). No statistical significance was identified. The IC 50 was calculated for each cell line.

Article Snippet: pp53 (Ser15) , Cell Signaling Technology , CAT# 9284; RRID: AB_331464.

Techniques: Functional Assay, Inhibition, Western Blot, Dominant Negative Mutation, Knock-Out, Control, Viability Assay, Staining

Journal: iScience

Article Title: IMPDH inhibition induces DNA replication stress and ATR sensitivity in Merkel cell carcinoma

doi: 10.1016/j.isci.2025.112567

Figure Lengend Snippet: Dual inhibition of IMPDH and ATR induces p53-independent replication catastrophe (A) Immunoblot of WaGa cells pre-induced with DOX (1 μg/mL) for 24 h to express p53DD or eGFP followed by treatment with MPA (1 μM) and berzosertib (250 nM) for an additional 24 h. Representative of 3 independent experiments. (B) Immunoblot of MKL-1 p53 KO or control (AAVS1) cells treated with MPA (1 μM) and berzosertib (250 nM) for 3 days. Representative of 3 independent experiments. For panels A and B, the total p53 blot is a reblot of pp53, the total KAP1 blot is a reblot of the pKAP1 blot, the total CHK1 blot is a reblot of pCHK1, and the total RPA32 blot is a reblot of pRPA32. (C) Flow cytometry analysis of chromatin-associated γH2AX and RPA32 in WaGa cells pre-induced and treated as in (A). Gating strategy for each defined population is shown. Images generated in FlowJo. Representative of 3 independent experiments. (D) Quantification of populations from (C). N = 3; mean ± SD. (E) Quantification of chromatin-associated CDC45 from WaGa cells treated as in (A). N = 3; mean ± SD; two-way ordinary ANOVA corrected for multiple comparisons via Tukey post hoc test; ∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001, ∗∗∗∗ p < 0.0001. (F) Quantification of chromatin-associated PCNA from WaGa cells treated as in (A). N = 3; mean ± SD; statistical tests are identical to (E). (G) Quantification of WaGa single cells dual-positive for AV and DAPI prepared as in (A) but treated with inhibitors for 2 days. N = 3; mean ± SD; statistical tests are identical to (E).

Article Snippet: pp53 (Ser15) , Cell Signaling Technology , CAT# 9284; RRID: AB_331464.

Techniques: Inhibition, Western Blot, Control, Flow Cytometry, Generated