Suberoylanilide hydroxamic acid upregulates histone acetylation and activates endoplasmic reticulum stress to induce apoptosis in HepG2 liver cancer cells

A Novel Class I HDAC Inhibitor, AW01178, Inhibits Epithelial-Mesenchymal Transition and Metastasis of Breast Cancer

Epithelial-mesenchymal transition (EMT) refers to the transformation of polar epithelial cells into motile mesenchymal cells under specific physiological or pathological conditions, thus promoting the metastasis of cancer cells. Epithelial cadherin (E-cadherin) is a protein that plays an important role in the acquisition of tumor cell motility and serves as a key EMT epithelial marker. In the present study, AW01178, a small-molecule compound with potential therapeutic efficacy, was identified via in-cell Western high-throughput screening technology using E-cadherin as the target. The compound induced the upregulation of E-cadherin at both mRNA and protein levels and inhibited the EMT of breast cancer cells in vitro as well as metastasis in vivo. Mechanistically, AW01178 is a novel benzacetamide histone deacetylase inhibitor (HDACi) mainly targeting class I histone deacetylases. AW01178 promoted the transcription and expression of E-cadherin through enhancing the acetylation level of histone H3 in the E-cadherin promoter region, thereby inhibiting the metastasis of breast cancer cells. The collective findings support the potential utility of the novel HDACi compound identified in this study, AW01178, as a therapeutic drug for breast cancer and highlight its value for the future development of HDACi structures as anticancer drugs.

Suberoylanilide hydroxamic acid upregulates reticulophagy receptor expression and promotes cell death in hepatocellular carcinoma cells

BACKGROUND

Hepatocellular carcinoma (HCC) is a common clinical condition with a poor prognosis and few effective treatment options. Potent anticancer agents for treating HCC must be identified. Epigenetics plays an essential role in HCC tumorigenesis. Suberoylanilide hydroxamic acid (SAHA), the most common histone deacetylase inhibitor agent, triggers many forms of cell death in HCC. However, the underlying mechanism of action remains unclear. Family with sequence similarity 134 member B (FAM134B)-induced reticulophagy, a selective autophagic pathway, participates in the decision of cell fate and exhibits anticancer activity. This study focused on the relationship between FAM134B-induced reticulophagy and SAHA-mediated cell death.

AIM

To elucidate potential roles and underlying molecular mechanisms of reticulophagy in SAHA-induced HCC cell death.

METHODS

The viability, apoptosis, cell cycle, migration, and invasion of SAHA-treated Huh7 and MHCC97L cells were measured. Proteins related to the reticulophagy pathway, mitochondria-endoplasmic reticulum (ER) contact sites, intrinsic mitochondrial apoptosis, and histone acetylation were quantified using western blotting. ER and lysosome colocalization, and mitochondrial Ca2+ levels were characterized via confocal microscopy. The level of cell death was evaluated through Hoechst 33342 staining and propidium iodide colocalization. Chromatin immunoprecipitation was used to verify histone H4 lysine-16 acetylation in the FAM134B promoter region.

RESULTS

After SAHA treatment, the proliferation of Huh7 and MHCC97L cells was significantly inhibited, and the migration and invasion abilities were greatly blocked in vitro. This promoted apoptosis and caused G1 phase cells to increase in a concentration-dependent manner. Following treatment with SAHA, ER-phagy was activated, thereby triggering autophagy-mediated cell death of HCC cells in vitro. Western blotting and chromatin immunoprecipitation assays confirmed that SAHA regulated FAM134B expression by enhancing the histone H4 lysine-16 acetylation in the FAM134B promoter region. Further, SAHA disturbed the Ca2+ homeostasis and upregulated the level of autocrine motility factor receptor and proteins related to mitochondria-endoplasmic reticulum contact sites in HCC cells. Additionally, SAHA decreased the mitochondrial membrane potential levels, thereby accelerating the activation of the reticulophagy-mediated mitochondrial apoptosis pathway and promoting HCC cell death in vitro.

CONCLUSION

SAHA stimulates FAM134B-mediated ER-phagy to synergistically enhance the mitochondrial apoptotic pathway, thereby enhancing HCC cell death.

Resveratrol inhibits ACHN cells via regulation of histone acetylation

Context: The relationship between resveratrol and histone acetylation in renal cell carcinoma (RCC) has not yet been reported.Objective: To explore the functional role of resveratrol in RCC.Materials and methods: Functional experiments were performed to determine proliferatio n of ACHN cells with treatment of resveratrol (0, 7.8125, 15.625, 31.25 and 62.5 μg/mL, for 12, 24 and 48 h of culture) or 0.1 μM SAHA. The enzyme activities of MMP-2/-9 were measured by gelatine zymography and histone acetylation by Western blot.Results: When the cells were treated with 15.625, 31.25 and 62.5 μg/mL resveratrol, ACHN cells viability was 73.2 ± 3.5%, 61.4 ± 3.1%, 50.2 ± 4.7% for 12 h, 62.7 ± 4.5%, 52.4 ± 5.5%, 40.2 ± 3.8% for 24 h, and 60.8 ± 3.7%, 39.4 ± 5.1%, 37.6 ± 2.7% for 48 h, and the wound closure (%) of migration was increased from 0.6 to 0.7, 0.85, 0.9 for 12 h and from 0.23 to 0.3, 0.48, 0.59 for 24 h. The invasion rate was 8.5 ± 0.9%, 7.4 ± 0.3% and 5.8 ± 0.6%, and cell cycle was arrested at G1 from 42.5 ± 2.9% to 55.3 ± 5.7%, 59.8 ± 3.4%, 68.7 ± 4.6%. MMP-2/-9 expression (p < 0.05) was inhibited by resveratrol. The protein levels of histone acetylation (p < 0.01) was increased by resveratrol.Discussion and conclusions: Our results suggest that these effects might be related to a high level of histone acetylation, and resveratrol can be considered as an alternative treatment for RCC.

Delicaflavone Reverses Cisplatin Resistance via Endoplasmic Reticulum Stress Signaling Pathway in Non-Small Cell Lung Cancer Cells

Background

The incidence and mortality of lung cancer continue to increase around the world; in 2018, new lung cancer cases accounted for 11.6% of all cancer cases, and lung cancer deaths accounted for 18.4% of cancer deaths. Cisplatin (DDP) is a first-line chemotherapy drug for lung cancer; however, DDP resistance can lead to a poor prognosis in patients with lung cancer. Therefore, reversing DDP resistance is a treatment goal.

Materials and Methods

Cell counting kit-8 (CCK8) assays, wound healing analyses, Transwell assays, in vitro tumor xenografts, and flow cytometry were used to detect the proliferation, migration, invasion, and apoptosis of multidrug resistant A549/DDP and PC9/DDP cells, respectively. Western blot was performed to detect protein levels of cleaved caspase-3, CHOP, and GRP78.

Results

Delicaflavone inhibited DDP resistance of lung cancer cells and decreased proliferation in a dose- and time-dependent manner. It also decreased migration and invasion and enhanced apoptosis. Western blots showed that delicaflavone overcame DDP resistance by increasing the expression of GRP78 and CHOP and the apoptosis-related protein cleaved caspase-3.

Conclusion

Delicaflavone can reverse DDP resistance in A549/DDP and PC9/DDP cells by inhibiting cell proliferation and migration and enhancing apoptosis and cleaved caspase-3 levels by increasing the expression of CHOP and GRP78 protein via the endoplasmic reticular stress pathway. It could be a useful therapeutic adjunct to treat DDP-resistant lung cancer.