The HDAC Inhibitor, SAHA, Combined with Cisplatin Synergistically Induces Apoptosis in Alpha-fetoprotein-producing Hepatoid Adenocarcinoma Cells

Histone Modification in Histochemistry and Cytochemistry

Keeping chromatin in a stable state is essential for genome stability, scheduled transcription, replication, DNA repair, and precise and reliable chromosome segregation and telomere maintenance during cell division. Over the past decade, research on chromatin remodeling has made great strides whereby modification of histone proteins is a key factor involved in many of the essential cellular processes. The nuclear findings of tumor cells that pathologists routinely examine are nothing but reflections of both genomic and histone alterations. Moreover, impaired histone function is known to be related to common diseases such as diabetes and atherosclerosis, and is, therefore, considered a potential therapeutic target. The present review first outlines the physiological function of histone proteins, and second, demonstrates their alterations to pathological states, emphasizing the importance of immunohistochemistry in histopathological diagnosis.

Deciphering the Role of Histone Modifications in Uterine Leiomyoma: Acetylation of H3K27 Regulates the Expression of Genes Involved in Proliferation, Cell Signaling, Cell Transport, Angiogenesis and Extracellular Matrix Formation

Uterine leiomyoma (UL) is a benign tumor arising from myometrium (MM) with a high prevalence and unclear pathology. Histone modifications are altered in tumors, particularly via histone acetylation which is correlated with gene activation. To identify if the acetylation of H3K27 is involved in UL pathogenesis and if its reversion may be a therapeutic option, we performed a prospective study integrating RNA-seq (n = 48) and CHIP-seq for H3K27ac (n = 19) in UL vs MM tissue, together with qRT-PCR of SAHA-treated UL cells (n = 10). CHIP-seq showed lower levels of H3K27ac in UL versus MM (p-value < 2.2 × 10−16). From 922 DEGs found in UL vs. MM (FDR < 0.01), 482 presented H3K27ac. A differential acetylation (FDR < 0.05) was discovered in 82 of these genes (29 hyperacetylated/upregulated, 53 hypoacetylated/downregulated). Hyperacetylation/upregulation of oncogenes (NDP,HOXA13,COL24A1,IGFL3) and hypoacetylation/downregulation of tumor suppressor genes (CD40,GIMAP8,IL15,GPX3,DPT) altered the immune system, the metabolism, TGFβ3 and the Wnt/β-catenin pathway. Functional enrichment analysis revealed deregulation of proliferation, cell signaling, transport, angiogenesis and extracellular matrix. Inhibition of histone deacetylases by SAHA increased expression of hypoacetylated/downregulated genes in UL cells (p < 0.05). Conclusively, H3K27ac regulates genes involved in UL onset and maintenance. Histone deacetylation reversion upregulates the expression of tumor suppressor genes in UL cells, suggesting targeting histone modifications as a therapeutic approach for UL.

Histone deacetylase inhibition by suberoylanilide hydroxamic acid: a therapeutic approach to treat human uterine leiomyoma

OBJECTIVE

To evaluate the effect of inhibition of histone deacetylases (HDACs) by suberoylanilide hydroxamic acid (SAHA) treatment of human uterine leiomyoma primary (HULP) cells in vitro on cell proliferation, cell cycle, extracellular matrix (ECM) formation, and transforming growth factor β3 (TGF-β3) signaling.

DESIGN

Prospective study comparing uterine leiomyoma (UL) vs. adjacent myometrium (MM) tissue and cells with or without SAHA treatment.

SETTING

Hospital and university laboratories.

PATIENT(S)

Women with UL without any hormone treatment.

INTERVENTION(S)

Myomectomy or hysterectomy surgery in women for leiomyoma disease.

MAIN OUTCOME MEASURE(S)

HDAC activity was assessed by enzyme-linked immunosorbent assay, and gene expression was assessed by quantitative real-time polymerase chain reaction. Effects of SAHA on HULP cells were analyzed by CellTiter (Promega, Madison, Wisconsin), Western blot, and quantitative real-time polymerase chain reaction.

RESULT(S)

The expression of HDAC genes (HDAC1, fold change [FC] = 1.65; HDAC3, FC = 2.08; HDAC6, FC = 2.42) and activity (0.56 vs. 0.10 optical density [OD]/h/mg) was significantly increased in UL vs. MM tissue. SAHA decreased HDAC activity in HULP cells but not in MM cells. Cell viability significantly decreased in HULP cells (81.68% at 5 μM SAHA, 73.46% at 10 μM SAHA), but not in MM cells. Proliferating cell nuclear antigen expression was significantly inhibited in SAHA-treated HULP cells (5 μM SAHA, FC = 0.556; 10 μM SAHA, FC = 0.622). Cell cycle markers, including C-MYC (5 μM SAHA, FC = 0.828) and CCND1 (5 μM SAHA, FC = 0.583; 10 μM SAHA, FC = 0.482), were significantly down-regulated after SAHA treatment. SAHA significantly inhibited ECM protein expression, including FIBRONECTIN (5 μM SAHA, FC = 0.815; 10 μM SAHA, FC = 0.673) and COLLAGEN I (5 μM SAHA, FC = 0.599; 10 μM SAHA, FC = 0.635), in HULP cells. TGFβ3 and MMP9 gene expression was also significantly down-regulated by 10 μM SAHA (TGFβ3, FC = 0.596; MMP9, FC = 0.677).

CONCLUSION(S)

SAHA treatment inhibits cell proliferation, cell cycle, ECM formation, and TGF-β3 signaling in HULP cells, suggesting that histone deacetylation may be useful for treatment of UL.

Metabolic Reprogramming Drives Pituitary Tumor Growth through Epigenetic Regulation of TERT

Pituitary adenomas are common, benign brain tumors. Some tumors show aggressive phenotypes including early recurrence, local invasion and distant metastasis, but the underlying mechanism to drive the progression of pituitary tumors has remained to be clarified. Aerobic glycolysis known as the Warburg effect is one of the emerging hallmarks of cancer, which has an impact on the tumor biology partly through epigenetic regulation of the tumor-promoting genes. Here, we demonstrate metabolic reprogramming in pituitary tumors contributes to tumor cell growth with epigenetic changes such as histone acetylation. Notably, a shift in histone acetylation increases the expression of telomerase reverse transcriptase (TERT) oncogene, which drives metabolism-dependent cell proliferation in pituitary tumors. These indicate that epigenetic changes could be the specific biomarker for predicting the behavior of pituitary tumors and exploitable as a novel target for the aggressive types of the pituitary tumors.

Small molecules in targeted cancer therapy: advances, challenges, and future perspectives

Due to the advantages in efficacy and safety compared with traditional chemotherapy drugs, targeted therapeutic drugs have become mainstream cancer treatments. Since the first tyrosine kinase inhibitor imatinib was approved to enter the market by the US Food and Drug Administration (FDA) in 2001, an increasing number of small-molecule targeted drugs have been developed for the treatment of malignancies. By December 2020, 89 small-molecule targeted antitumor drugs have been approved by the US FDA and the National Medical Products Administration (NMPA) of China. Despite great progress, small-molecule targeted anti-cancer drugs still face many challenges, such as a low response rate and drug resistance. To better promote the development of targeted anti-cancer drugs, we conducted a comprehensive review of small-molecule targeted anti-cancer drugs according to the target classification. We present all the approved drugs as well as important drug candidates in clinical trials for each target, discuss the current challenges, and provide insights and perspectives for the research and development of anti-cancer drugs.

Protein Acetylation at the Interface of Genetics, Epigenetics and Environment in Cancer

Metabolic reprogramming is an emerging hallmark of cancer and is driven by abnormalities of oncogenes and tumor suppressors. Accelerated metabolism causes cancer cell aggression through the dysregulation of rate-limiting metabolic enzymes as well as by facilitating the production of intermediary metabolites. However, the mechanisms by which a shift in the metabolic landscape reshapes the intracellular signaling to promote the survival of cancer cells remain to be clarified. Recent high-resolution mass spectrometry-based proteomic analyses have spotlighted that, unexpectedly, lysine residues of numerous cytosolic as well as nuclear proteins are acetylated and that this modification modulates protein activity, sublocalization and stability, with profound impact on cellular function. More importantly, cancer cells exploit acetylation as a post-translational protein for microenvironmental adaptation, nominating it as a means for dynamic modulation of the phenotypes of cancer cells at the interface between genetics and environments. The objectives of this review were to describe the functional implications of protein lysine acetylation in cancer biology by examining recent evidence that implicates oncogenic signaling as a strong driver of protein acetylation, which might be exploitable for novel therapeutic strategies against cancer.

Photodynamic Therapy Using a Novel Phosphorus Tetraphenylporphyrin Induces an Anticancer Effect via Bax/Bcl-xL-related Mitochondrial Apoptosis in Biliary Cancer Cells

Photodynamic therapy (PDT) uses photosensitizer activation by light of a specific wavelength, and is a promising treatment for various cancers; however, the detailed mechanism of PDT remains unclear. Therefore, we investigated the anticancer effect of PDT using a novel phosphorus tetraphenylporphyrin (Ptpp) in combination with light emitting diodes (Ptpp-PDT) in the NOZ human biliary cancer cell line. Cell viability and apoptosis were examined by MTT assay, flow cytometry and TUNEL assay for 24 hr after Ptpp-PDT. MitoTracker and JC-1 were used as markers of mitochondrial localization and membrane potential. The levels of mitochondrial oxidative phosphorylation (OXPHOS) complexes, Bcl-2 family proteins, cytochrome c and cleaved caspase-3 were examined by western blotting and immunohistochemistry. The results revealed that Ptpp localized to mitochondria, and that Ptpp-PDT efficiently decreased cell viability in a dose- and time-dependent manner. JC-1 and OXPHOS complexes decreased, but apoptotic cells increased from 6 to 24 hr after Ptpp-PDT. A decrease in Bcl-xL and increases in Bax, cytochrome c and cleaved caspase-3 were also found from 6 to 24 hr after Ptpp-PDT. Based on these results, we conclude that Ptpp-PDT induces anticancer effects via the mitochondrial apoptotic pathway by altering the Bax/Bcl-xL ratio, and could be an effective treatment for human biliary cancer.

Cavenee W, S. Mischel P, Shibata N. Codependency of Metabolism and Epigenetics Drives Cancer Progression: A Review

Cancer is widely considered to be a set of genetic diseases that are currently classified by tissue and cell type of origin and, increasingly, by its molecular characteristics. This latter aspect is based primarily upon oncogene gains, tumor suppressor losses, and associated transcriptional profiles. However, cancers are also characterized by profound alterations in cellular metabolism and epigenetic landscape. It is particularly noteworthy that cancer-causing genomic defects not only activate cell cycle progression, but regulate the opportunistic uptake and utilization of nutrients, effectively enabling tumors to maximize growth and drug resistance in changing tissue and systemic microenvironments. Shifts in chromatin architecture are central to this dynamic behavior. Further, changes in nutrient uptake and utilization directly affect chromatin structure. In this review, we describe a set of recent discoveries of metabolic and epigenetic reprogramming in cancer, and especially focus on the genomically well-characterized brain tumor, glioblastoma. Further, we discuss a new mode of metabolic regulation driven by epigenetic mechanisms, that enables cancer cells to autonomously activate iron metabolism for their survival. Together, these underscore the integration of genetic mutations with metabolic reprogramming and epigenetic shifts in cancer, suggesting a new means to identifying patient subsets suitable for specific precision therapeutics.

Long-term Pilocarpine Treatment Improves Salivary Flow in Irradiated Mice

Radiation therapy for head and neck cancer frequently causes salivary gland dysfunction. Pilocarpine is a clinically approved and effective drug that induces saliva secretion, thereby keeping the oral mucosa moist and reducing discomfort in patients, but the effect is transient. We expected that this drug also has beneficial long-term effects that maintain the integrity of salivary glands by reducing, for instance, apoptosis. Here, we examined the effects of long-term pilocarpine administration in irradiated mice. The results indicated that long-term pilocarpine administration significantly improved salivary flow in irradiated mice, suggesting the potential beneficial effects of long-term administration. To elucidate the underlying mechanism, we analyzed the histology, apoptosis, and proliferation of acinar cells, and the expression of functional membrane proteins such as transmembrane member 16A, aquaporin-5, and Na-K-Cl cotransporter. Long-term pilocarpine treatment seemed to decrease irradiation-induced apoptosis, although the change was not statistically significant. The present results indicated that long-term administration of pilocarpine has beneficial effects on salivary flow in irradiated mice, and suggested that long-term administration possibly decreases apoptosis in irradiated salivary glands.