Histone deacetylase inhibitors potentiate photodynamic therapy in colon cancer cells marked by chromatin-mediated epigenetic regulation of CDKN1A

Shedding Light on Chemoresistance: The Perspective of Photodynamic Therapy in Cancer Management

The persistent failure of standard chemotherapy underscores the urgent need for innovative and targeted approaches in cancer treatment. Photodynamic therapy (PDT) has emerged as a promising photochemistry-based approach to address chemoresistance in cancer regimens. PDT not only induces cell death but also primes surviving cells, enhancing their susceptibility to subsequent therapies. This review explores the principles of PDT and discusses the concept of photodynamic priming (PDP), which augments the effectiveness of treatments like chemotherapy. Furthermore, the integration of nanotechnology for precise drug delivery at the right time and location and PDT optimization are examined. Ultimately, this study highlights the potential and limitations of PDT and PDP in cancer treatment paradigms, offering insights into future clinical applications.

Pharmaceutical Approach to Develop Novel Photosensitizer Nanoformulation: An Example of Design and Characterization Rationale of Chlorophyll α Derivative

In this study, we described physico-chemical properties of novel nanoformulation of photosensitizer-pyropheophorbide α 17-diethylene glycol ester (XL) (chlorophyll α derivative), revealing insights into antitumor activity and maintaining quality, meeting the pharmaceutical approach of new nanoformulation design. Our formulation, based on poly(lactic-co-glycolic acid) (PLGA) nanoparticles, increased XL solubility and selective tumor-targeted accumulation. In our research, we revealed, for the first time, that XL binding to polyvinyl alcohol (PVA) enhances XL photophysical activity, providing the rationale for PVA application as a stabilizer for nanoformulations. Results of FTIR, DSC, and XRD revealed the physical interactions between XL and excipients, including PVA, indicating that the encapsulation maintained XL binding to PVA. The encapsulated XL exhibited higher photophysical activity compared to non-encapsulated substance, which can be attributed to the influence of residual PVA. Gamma-irradiation led to degradation of XL; however, successful sterilization of the samples was achieved through the filtration. Importantly, the encapsulated and sterilized XL retained cytotoxicity against both 2D and 3D tumor cell models, demonstrating the potential of the formulated NP-XL for photodynamic therapy applications, but lacked the ability to reactivate epigenetically silenced genes. These findings provide valuable insights into the design and characterization of PLGA-based nanoparticles for the encapsulation of photosensitizers.

Photodynamic Therapy and Immunological View in Gastrointestinal Tumors

Gastrointestinal cancers are a specific group of oncological diseases in which the location and nature of growth are of key importance for clinical symptoms and prognosis. At the same time, as research shows, they pose a serious threat to a patient's life, especially at an advanced stage of development. The type of therapy used depends on the anatomical location of the cancer, its type, and the degree of progression. One of the modern forms of therapy used to treat gastrointestinal cancers is PDT, which has been approved for the treatment of esophageal cancer in the United States. Despite the increasingly rapid clinical use of this treatment method, the exact immunological mechanisms it induces in cancer cells has not yet been fully elucidated. This article presents a review of the current understanding of the mode of action of photodynamic therapy on cells of various gastrointestinal cancers with an emphasis on colorectal cancer. The types of cell death induced by PDT include apoptosis, necrosis, and pyroptosis. Anticancer effects are also a result of the destruction of tumor vasculature and activation of the immune system. Many reports exist that concern the mechanism of apoptosis induction, of which the mitochondrial pathway is most often emphasized. Photodynamic therapy may also have a beneficial effect on such aspects of cancer as the ability to develop metastases or contribute to reducing resistance to known pharmacological agents.

Hypericin: A natural anthraquinone as promising therapeutic agent

BACKGROUND

Hypericin is a prominent secondary metabolite mainly existing in genus Hypericum. It has become a research focus for a quiet long time owing to its extensively pharmacological activities especially the anti-cancer, anti-bacterial, anti-viral and neuroprotective effects. This review concentrated on summarizing and analyzing the existing studies of hypericin in a comprehensive perspective.

METHODS

The literature with desired information about hypericin published after 2010 was gained from electronic databases including PubMed, SciFinder, Science Direct, Web of Science, China National Knowledge Infrastructure databases and Wan Fang DATA.

RESULTS

According to extensive preclinical and clinical studies conducted on the hypericin, an organized and comprehensive summary of the natural and artificial sources, strategies for improving the bioactivities, pharmacological activities, drug combination of hypericin was presented to explore the future therapeutic potential of this active compound.

CONCLUSIONS

Overall, this review offered a theoretical guidance for the follow-up research of hypericin. However, the pharmacological mechanisms, pharmacokinetics and structure activity relationship of hypericin should be further studied in future research.

Leader gene identification for digestive system cancers based on human subcellular location and cancer-related characteristics in protein–protein interaction networks

Stomach, liver, and colon cancers are the most common digestive system cancers leading to mortality. Cancer leader genes were identified in the current study as the genes that contribute to tumor initiation and could shed light on the molecular mechanisms in tumorigenesis. An integrated procedure was proposed to identify cancer leader genes based on subcellular location information and cancer-related characteristics considering the effects of nodes on their neighbors in human protein–protein interaction networks. A total of 69, 43, and 64 leader genes were identified for stomach, liver, and colon cancers, respectively. Furthermore, literature reviews and experimental data including protein expression levels and independent datasets from other databases all verified their association with corresponding cancer types. These final leader genes were expected to be used as diagnostic biomarkers and targets for new treatment strategies. The procedure for identifying cancer leader genes could be expanded to open up a window into the mechanisms, early diagnosis, and treatment of other cancer types.

TMP195 Exerts Antitumor Effects on Colorectal Cancer by Promoting M1 Macrophages Polarization

Studies have shown that epigenetic enzymes such as histone deacetylase (HDAC) are closely related to cancers and that several HDAC inhibitors exert antitumor effects. Studies have further suggested that class IIa HDAC inhibitors are related to immune functions, including immune responses and the expression of chemokines and complement pathway components. TMP195, a selective class IIa HDAC inhibitor, has been reported to be effective against breast cancer. However, the role and mechanism of TMP195 in colorectal cancer remain unknown. In this study, we found that TMP195 significantly reduced the tumor burden in two mouse models of colitis-associated colorectal cancer (CAC) and subcutaneous tumor. Mechanistically, TMP195 decreased the proportion of total macrophages but increased the proportion of M1 macrophages by promoting polarization, resulting in the increased release of inflammatory cytokines. TMP195 had no direct effect on the proliferation of colorectal cancer cells, and its antitumor effect on the colorectal cancer disappeared when macrophages were partly depleted by clodronate liposomes. In addition, TMP195 enhanced the efficacy of PD-1 blockade. The present study revealed that the combination of TMP195 and PD-1 blockade may provide a therapeutic strategy for colorectal cancer.

Inhibition of the HIF-1 Survival Pathway as a Strategy to Augment Photodynamic Therapy Efficacy

Photodynamic therapy (PDT) is a non-to-minimally invasive treatment modality that utilizes photoactivatable drugs called photosensitizers to disrupt tumors with locally photoproduced reactive oxygen species (ROS). Photosensitizer activation by light results in hyperoxidative stress and subsequent tumor cell death, vascular shutdown and hypoxia, and an antitumor immune response. However, sublethally afflicted tumor cells initiate several survival mechanisms that account for decreased PDT efficacy. The hypoxia inducible factor 1 (HIF-1) pathway is one of the most effective cell survival pathways that contributes to cell recovery from PDT-induced damage. Several hundred target genes of the HIF-1 heterodimeric complex collectively mediate processes that are involved in tumor cell survival directly and indirectly (e.g., vascularization, glucose metabolism, proliferation, and metastasis). The broad spectrum of biological ramifications culminating from the activation of HIF-1 target genes reflects the importance of HIF-1 in the context of therapeutic recalcitrance. This chapter elaborates on the involvement of HIF-1 in cancer biology, the hypoxic response mechanisms, and the role of HIF-1 in PDT. An overview of inhibitors that either directly or indirectly impede HIF-1-mediated survival signaling is provided. The inhibitors may be used as pharmacological adjuvants in combination with PDT to augment therapeutic efficacy.

Epigenetic remodelling of enhancers in response to estrogen deprivation and re-stimulation

Estrogen hormones are implicated in a majority of breast cancers and estrogen receptor alpha (ER), the main nuclear factor mediating estrogen signaling, orchestrates a complex molecular circuitry that is not yet fully elucidated. Here, we investigated genome-wide DNA methylation, histone acetylation and transcription after estradiol (E2) deprivation and re-stimulation to better characterize the ability of ER to coordinate gene regulation. We found that E2 deprivation mostly resulted in DNA hypermethylation and histone deacetylation in enhancers. Transcriptome analysis revealed that E2 deprivation leads to a global down-regulation in gene expression, and more specifically of TET2 demethylase that may be involved in the DNA hypermethylation following short-term E2 deprivation. Further enrichment analysis of transcription factor (TF) binding and motif occurrence highlights the importance of ER connection mainly with two partner TF families, AP-1 and FOX. These interactions take place in the proximity of E2 deprivation-mediated differentially methylated and histone acetylated enhancers. Finally, while most deprivation-dependent epigenetic changes were reversed following E2 re-stimulation, DNA hypermethylation and H3K27 deacetylation at certain enhancers were partially retained. Overall, these results show that inactivation of ER mediates rapid and mostly reversible epigenetic changes at enhancers, and bring new insight into early events, which may ultimately lead to endocrine resistance.

Polymerized vorinostat mediated photodynamic therapy using lysosomal spatiotemporal synchronized drug release complex

A combination of photodynamic therapy (PDT) and histone deacetylase inhibitor (HDACis) could potentiate single-mode anti-tumor activity of HDACis or PDT to inhibit tumor relapse and metastasis. However, poor solubility and heterogeneity in cellular uptake and tissue distribution hamper the dual mode antitumor effect. For a controlled drug release of photosensitizers and HDACis in cytoplasm, photosensitizer pyropheophorbide-a (Pyro) encapsulated in polymer polyethylene glycol-b-poly (asparaginyl-vorinostat) (simplified as Pyro@FPPS) are fabricated to achieve their lysosomal spatiotemporal synchronized release. With HDACis modeling PDT in vitro and in vivo, it seems that polymerized Vorinostat encapsulated photosensitizers significantly inhibited the tumor proliferation and metastasis by spatiotemporal synchronized drugs release, and Pyro@FPPS reported here reveals a promising prospect to exert drugs' synergistic effect in a spatiotemporal synchronized manner and can be an effective strategy to inhibit tumor growth, recurrence and metastasis in clinic.

A valproic acid-modified platinum diimine complex as potential photosensitizer for photodynamic therapy

Histone deacetylase inhibitors have often been used in combination treatment of various types of cancers due to their non-genotoxic epigenetic potential. Valproic acid (VPA) is a well-known histone deacetylase inhibitor. Conjugate of VPA with a phtoactive platinum diimine complex through an ester bond has been fabricated to potentiate the photocytotoxicity of the photosensitizer. Its capability to generate singlet oxygen, behavior in the presence of esterase, and photocytotoxicity in tumor cells have also been studied. The results revealed that the novel VPA-modified platinum diimine complex could produce singlet oxygen efficiently and release VPA in the presence of porcine liver esterase. The results also suggested that incorporation of VPA moiety into the platinum diimine complex might significantly enhance the cytotoxicity of the complex.

Hypericin Induces Apoptosis in AGS Cell Line with No Significant Effect on Normal Cells

It is of great importance to find an effective approach that not only eliminates gastric cancer cells but also do exhibits significant side effect to normal cells. Some studies have shown the effectiveness of hypericin against cancer cells. In this study, we evaluated the anti-cancer effect of Hypericin in the treatment of gastric cancer. In this study, the AGS cell line was exposed to different concentrations of hypericin for 24 and 48 h. Evaluation of cell death was done by MTT assay. The rate of apoptosis was measured by flow cytometry assay using Annexin V/ Propidium Iodide. The expression rate of Bcl2, p53 and Bax genes was evaluated by Real-time PCR test, and immunocytochemistry (ICC) analysis and western blotting was used for further evaluation of p53. MTT assay test showed that hyepricin induces 50% cell death in the concentration of 1 (µg/mL) and 0.5 (µg/mL) at 24 h and 48 h post-treatment, respectively, however no similar effect seen on fibroblast cells. Annexin/PI test revealed that cell apoptosis after exposure to hypericin for 24 h was 74%. Real-time PCR showed that expression level of Bax, p53 and Bax genes increases and Bcl2 gene decreases in AGS cell lines after treatment by hypericin. ICC analysis and western blotting for p53 confirmed these data. The results of this study indicated that hypericin has the potential to be introduced as an effective treatment for gastric cancer. Therefore, it seems that this substance has potential to be utilized as anti-cancer drug.

Effect of the hydroxamate group in the antitumoral activity and toxicity toward normal cells of new copper(II) complexes

The synthesis, physico-chemical characterization and cytotoxicity of four copper(II) coordination complexes, i.e. [Cu(HBPA)Cl₂] (1), [Cu(BHA)₂] (2), [Cu(HBPA)(BHA)Cl] CH₃OH (3) and [Cu(HBPA)₂]Cl₂·4H₂O (4), are reported. HBPA is the tridentate ligand N-(2-hydroxybenzyl)-N-(2-pyridylmethyl)amine and HBHA is the benzohydroxamic acid. The reaction between the HBHA and CuCl₂.2H₂O has resulted in the new complex (2) and the reaction between complex (1) and HBHA has resulted in the new complex (3). X-ray diffraction studies for complex (3) indicated the effective coordination of HBHA as BHA^-. Their cytotoxicity was evaluated against three human tumoral cell lines (Colo-205, NCI-H460 and U937) and PBMC (peripheral blood mononuclear cells), using the MTT cytotoxic assay. The results toward PBMC reveal that the new copper(II) complex (2) presents lower toxicity toward normal cells. Furthermore, complex (2) presents IC₅₀ values lower than cisplatin toward NCI-H460 and the best selectivity index obtained towards NCI-H460 (SI = 2.2) and U937 cell lines (SI = 2.0), as a result of the presence of two molecules of HBHA in its structure. Complex (3) presents IC₅₀ values lower than cisplatin toward NCI-H460, Colo-205 and comparable to cisplatin toward U937. The evaluation of the cell death type promoted by complexes (2) and (4) was investigated toward NCI-H460 revealing better results than the standard drug cisplatin, according to the Annexin V and propidium iodide (PI) labeling experiment. Based on the studies here performed, HBHA seems to be related to lower toxicity toward PBMC and HBPA is improving directly the cytotoxity.

Evaluation of histone deacetylase inhibitor substituted zinc and indium phthalocyanines for chemo- and photodynamic therapy

In this study, we synthesized and characterized 3-hydroxypyridin-2-thione (3-HPT) bearing zinc (ZnPc-1 and ZnPc-2) and indium (InPc-1 and InPc-2) phthalocyanine (Pc) derivatives, either non-peripherally or peripherally substituted as photosensitizer (PS) agents and evaluated their anti-cancer efficacy on two breast cancer cell lines, MDA-MB-231 and MCF-7 as well as a human endothelial cell line, HUVEC. Our results indicated different localization patterns between ZnPcs and InPcs in addition to enhanced effects on the mitochondrial network for InPcs. Moreover, peripheral or non-peripheral substitution of HDACi moieties altered cellular localization between ZnPc-1 and ZnPc-2, leading to increased IC₅₀ values along with decreased anti-cancer activity for non-peripheral substitution. When considering the compounds' differential effects in vitro, our data indicates that further research is required to determine the ideal Pcs for anti-cancer PDT treatments since the core metals of the compounds have affected the cellular localization, and positioning of the chemotherapeutic residues may inhibit cellular penetrance.

3-Hydroxypyridin-2-thione bearing zinc and indium phthalocyanine derivatives, as photosensitizer agents have been synthesized and evaluated for their anti-cancer efficacy on two breast cancer cell lines, MDA-MB-231 and MCF-7 as well as a human endothelial cell line, HUVEC.

Epigenetic Effects Mediated by Antiepileptic Drugs and their Potential Application

An epigenetic effect mainly refers to a heritable modulation in gene expression in the short term but does not involve alterations in the DNA itself. Epigenetic molecular mechanisms include DNA methylation, histone modification, and untranslated RNA regulation. Antiepileptic drugs have drawn attention to biological and translational medicine because their impact on epigenetic mechanisms will lead to the identification of novel biomarkers and possible therapeutic strategies for the prevention and treatment of various diseases ranging from neuropsychological disorders to cancers and other chronic conditions. However, these transcriptional and posttranscriptional alterations can also result in adverse reactions and toxicity in vitro and in vivo. Hence, in this review, we focus on recent findings showing epigenetic processes mediated by antiepileptic drugs to elucidate their application in medical experiments and shed light on epigenetic research for medicinal purposes.

A Translational Study of a Silicon Phthalocyanine Substituted with a Histone Deacetylase Inhibitor for Photodynamic Therapy

In this study, we synthesized and characterized a silicon phthalocyanine substituted with 3-hydroxypyridin-2-thione (SiPc-HDACi), designed to be a chemophotodynamic therapy agent acting as a histone deacetylase inhibitor, and we determined its photophysical, photochemical, and photobiological properties. Next, we evaluated its anticancer efficacy on MCF-7, double positive and MDA-MB-231, triple negative breast cancer cell lines, as well as on a healthy human endothelial cell line (HUVEC). Our results indicate that SiPc-HDACi can target nucleoli of cells, effectively inducing apoptosis while promoting cell cycle arrest thanks to its high singlet oxygen yield and its histone deacetylase downregulating properties, suggesting a powerful anticancer effect on breast cancer in vitro. Our further studies will be conducted with primary breast cancer cell culture to give a better insight into the anticancer mechanism of the compound.

Potentiality, Limitations, and Consequences of Different Experimental Models to Improve Photodynamic Therapy for Cancer Treatment in Relation to Antiangiogenic Mechanism

The relevance of experimentally gained information represents a long-term debating issue in the field of molecular biology research. The loss of original conditions in the in vitro environment affects various biological mechanisms and cellular interactions. Consequently, some biochemical mechanisms are lost or critically altered. Analyses in these modified conditions could, therefore, distort the relevancy of experimentally gained information. In some cases, the similarities with original conditions are so small that utilization of simpler in vitro models seems impossible, or could occur in a very limited way. To conclude, the study of more complex phenomena places higher demands on the complexity of the experimental model. The latest information highlights the fact that the tumor angiogenesis mechanism has very complex features. This complexity can be associated with a wide range of angiogenic factors expressed by a variety of malignant and non-malignant cells. Our article summarizes the results from various experimental models that were utilized to analyze a photodynamic therapy effect on tumor angiogenic mechanisms. Additionally, based on the latest information, we present the most important attributes and limitations of utilized experimental models. We also evaluate the essential problems associated with angiogenic mechanism induction after photodynamic therapy application.

Romidepsin (FK228) regulates the expression of the immune checkpoint ligand PD-L1 and suppresses cellular immune functions in colon cancer

Romidepsin (FK228), a histone deacetylase inhibitor (HDACi), has anti-tumor effects against several types of solid tumors. Studies have suggested that HDACi could upregulate PD-L1 expression in tumor cells and change the state of anti-tumor immune responses in vivo. However, the influence of enhanced PD-L1 expression in tumor cells induced by romidepsin on anti-tumor immune responses is still under debate. So, the purpose of this study was to explore the anti-tumor effects and influence on immune responses of romidepsin in colon cancer. The results indicated that romidepsin inhibited proliferation, induced G0/G1 cell cycle arrest and increased apoptosis in CT26 and MC38 cells. Romidepsin treatment increased PD-L1 expression in vivo and in vitro via increasing the acetylation levels of histones H3 and H4 and regulating the transcription factor BRD4. In subcutaneous transplant tumor mice and colitis-associated cancer (CAC) mice, romidepsin increased the percentage of FOXP3+ regulatory T cells (Tregs), decreased the ratio of Th1/Th2 cells and the percentage of IFN-γ+ CD8+ T cells in the peripheral blood and the tumor microenvironment. Upon combination with an anti-PD-1 antibody, the anti-tumor effects of romidepsin were enhanced and the influence on CD4+ and CD8+ T cells was partially reversed. Therefore, the combination of romidepsin and anti-PD-1 immunotherapy provides a more potential treatment for colon cancer.

p62 manipulation affects chlorin e6-mediated photodynamic therapy efficacy in colorectal cancer cell lines

p62 is a multifunctional protein that mediates cell signaling pathways, autophagy and tumorigenesis, and participates in important regulation processes at the intersection between autophagy and cancer. Photodynamic therapy (PDT) is a treatment that involves photosensitizing agents and light to kill cancer cells. However, whether the efficacy of PDT depends on the expression level of p62 in colorectal cancer cell lines is not known. The present study aimed to examine the role of p62 expression levels in chlorin e6-based PDT in colorectal cancer cells. To study the effect of p62 on cancer cell death, we used PDT to treat a stable cell line overexpressing p62. Cells overexpressing p62 showed a higher cell death rate than cells not expressing this protein. Overexpression of p62 may contribute to colorectal cancer cell death. These results provide preliminary evidence for use of p62 as a therapy target to treat colorectal cancer.

Photodynamic diagnosis and photodynamic therapy of colorectal cancer in vitro and in vivo

This review highlights the various photo diagnostic and treatment methods utilized for CRC, over the last seven years.

Photodynamic therapy inhibits cell growth and enhances the histone deacetylase-mediated viability impairment in Cryptococcus spp. in vitro

Cryptococcosis is a disseminated infection caused mainly by C. neoformans and C. gattii. Limitations for the treatment involve the selection of isolates resistant to conventional antifungal drugs, prolonged treatment time and drugs side effects. This study evaluated the combined effect of histone deacetylase inhibitors (HDACi) and photodynamic therapy (PDT) on the growth of C. neoformans and C. gattii in vitro. Results showed that PDT inhibited yeasts proliferation and enhanced the HDACi-mediated cell viability impairment in Cryptococcus spp.

Epigenetic Regulation of p21cip1/waf1 in Human Cancer

p21^cip1/waf1 is a central regulator of cell cycle control and survival. While mutations are rare, it is commonly dysregulated in several human cancers due to epigenetic mechanisms influencing its transcriptional control. These mechanisms include promoter hypermethylation as well as additional pathways such as histone acetylation or methylation. The epigenetic regulators include writers, such as DNA methyltransferases (DNMTs); histone acetyltransferases (HATs) and histone lysine methyltransferases; erasers, such as histone deacetylases (HDACs); histone lysine demethylases [e.g., the Lysine Demethylase (KDM) family]; DNA hydroxylases; readers, such as the methyl-CpG-binding proteins (MBPs); and bromodomain-containing proteins, including the bromo- and extraterminal domain (BET) family. We further discuss the roles that long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) play in the epigenetic control of p21^cip1/waf1 expression and its function in human cancers.

Folate-mediated and pH-responsive chidamide-bound micelles encapsulating photosensitizers for tumor-targeting photodynamic therapy

Background: Nonspecific tumor targeting, potential relapse and metastasis of tumor after treatment are the main barriers in clinical photodynamic therapy (PDT) for cancer, hence, inhibiting relapse and metastasis of tumor is significant issues in clinic. Purpose: In this work, chidamide as a histone deacetylases inhibitor (HADCi) was bound onto a pH-responsive block polymer folate polyethylene glycol-b-poly(aspartic acid) (PEG-b-PAsp) grafted folate (FA-PEG-b-PAsp) to obtain the block polymer folate polyethylene glycol-b-poly(asparaginyl-chidamide) (FA-PEG-b-PAsp-chidamide, FPPC) as multimodal tumor-targeting drug-delivery carrier to inhibiting tumor cell proliferation and tumor metastasis in mice. Methods: Model photosensitizer pyropheophorbide-a (Pha) was encapsulated by FPPC in PBS to form the polymer micelles Pha@FPPC [folate polyethylene glycol-b-poly(asparaginyl-chidamide) micelles encapsulating Pha]. Pha@FPPC was characterized by transmission electron microscope and dynamic light scattering; also, antitumor activity in vivo and in vitro were investigated by determination of cellular ROS level, detection of cell apoptosis and cell cycle arrest, PDT antitumor activity in vivo and histological analysis. Results: With favorable and stable sphere morphology under transmission electron microscope (TEM) (~93.0 nm), Pha@FPPC greatly enhanced the cellular uptake due to its folate-mediated effective endocytosis by mouse melanoma B16-F10 cells and the yield of ROS in tumor cells induced by PDT, and mainly caused necrocytosis and blocked cell growth cycle not only in G2 phase but also in G1/G0 phase after PDT. Pha@FPPC exhibited lower dark cytotoxicity in vitro and a better therapeutic index because of its higher dark cytotoxicity/photocytotoxicity ratio. Moreover, Pha@FPPC not only significantly inhibited the growth of implanted tumor and prolonged the survival time of melanoma-bearing mice due to both its folate-mediated tumor-targeting and selectively accumulation at tumor site by EPR (enhanced permeability and retention)effect as micelle nanoparticles but also remarkably prevented pulmonary metastasis of mice melanoma after PDT compared to free Pha, demonstrating its dual antitumor characteristics of PDT and HDACi. Conclusion: As a folate-mediated and acid-activated chidamide-grafted drug-delivery carrier, FPPC may have great potential to inhibit tumor metastasis in clinical photodynamic treatment for cancer because of its effective and multimodal tumor-targeting performance as photosensitizer vehicle.

Loss of KDM6A characterizes a poor prognostic subtype of human pancreatic cancer and potentiates HDAC inhibitor lethality

Although genomic analysis have recently discovered the malignant subtype of human pancreatic ductal adenocarcinoma (PDAC) characterized by frequent mutations of histone demethylase KDM6A, the biological and molecular roles still remain obscure. We herein elucidated the clinical and biological impacts of KDM6A deficiency on human PDAC and identified the therapeutic potential by pathological and molecular evaluation. Immunohistochemical analysis suggested that loss of KDM6A in cancerous tissues was an independent prognostic factor for both recurrence-free and overall survival in the 103 tumor specimens surgically resected from patients with PDAC. We established KDM6A knocked out cells by using the CRISPR/Cas9 system and KDM6A-expressed cells by doxycycline-inducible system from each two human PDAC cell lines, respectively. KDM6A knockout enhanced aggressive traits of human PDAC cell lines, whereas KDM6A overexpression suppressed them. Microarray analysis revealed reduced expression of 22 genes including five well-known tumor suppressors, such as CDKN1A, and ChIP-PCR analysis displayed depleted enrichment of histone H3 lysine 27 acetylation (H3K27ac) at the promoter regions of the five candidates. The epigenetic alterations were induced by the impaired recruitment of histone acetyltransferase p300, which cooperatively interacted with KDM6A. Consistent with these results, the KDM6A knockout cells demonstrated higher vulnerability to histone deacetylase (HDAC) inhibitors through the reactivation of CDKN1A in vitro and in vivo than the KDM6A wild-type. In conclusion, KDM6A exhibited essential roles in human PDAC as a tumor suppressor and KDM6A deficiency could be a promising biomarker for unfavorable outcome in PDAC patients and a potential surrogate marker for response to HDAC inhibitors.