Targeting mitochondrial hexokinases increases efficacy of histone deacetylase inhibitors in solid tumor models

The Promoting Role of HK II in Tumor Development and the Research Progress of Its Inhibitors

Increased glycolysis is a key characteristic of malignant cells that contributes to their high proliferation rates and ability to develop drug resistance. The glycolysis rate-limiting enzyme hexokinase II (HK II) is overexpressed in most tumor cells and significantly affects tumor development. This paper examines the structure of HK II and the specific biological factors that influence its role in tumor development, as well as the potential of HK II inhibitors in antitumor therapy. Furthermore, we identify and discuss the inhibitors of HK II that have been reported in the literature.

The hexokinase "HKDC1" interaction with the mitochondria is essential for liver cancer progression

Liver cancer (LC) is the fourth leading cause of death from cancer malignancies. Recently, a putative fifth hexokinase, hexokinase domain containing 1 (HKDC1), was shown to have significant overexpression in LC compared to healthy liver tissue. Using a combination of in vitro and in vivo tools, we examined the role of HKDC1 in LC development and progression. Importantly, HKDC1 ablation stops LC development and progression via its action at the mitochondria by promoting metabolic reprogramming and a shift of glucose flux away from the TCA cycle. HKDC1 ablation leads to mitochondrial dysfunction resulting in less cellular energy, which cannot be compensated by enhanced glucose uptake. Moreover, we show that the interaction of HKDC1 with the mitochondria is essential for its role in LC progression, and without this interaction, mitochondrial dysfunction occurs. As HKDC1 is highly expressed in LC cells, but only to a minimal degree in hepatocytes under normal conditions, targeting HKDC1, specifically its interaction with the mitochondria, may represent a highly selective approach to target cancer cells in LC.

Dual Inhibition of Histone Deacetylases and the Mechanistic Target of Rapamycin Promotes Apoptosis in Cell Line Models of Uveal Melanoma

Purpose

Over 90% of uveal melanomas harbor pathogenic variants of the GNAQ or GNA11 genes that activate survival pathways. As previous studies found that Ras-mutated cell lines were vulnerable to a combination of survival pathway inhibitors and the histone-deacetylase inhibitor romidepsin, we investigated whether this combination would be effective in models of uveal melanoma.

Methods

A small-scale screen of inhibitors of bromodomain-containing protein 4 (BRD4; OTX-015), extracellular signal-related kinase (ERK; ulixertinib), mechanistic target of rapamycin (mTOR; AZD-8055), or phosphoinositide 3-kinase (PI3K; GDC-0941) combined with a clinically relevant administration of romidepsin was performed on a panel of uveal melanoma cell lines (92.1, Mel202, MP38, and MP41) and apoptosis was quantified by flow cytometry after 48 hours. RNA sequencing analysis was performed on Mel202 cells treated with romidepsin alone, AZD-8055 alone, or the combination, and protein changes were validated by immunoblot.

Results

AZD-8055 with romidepsin was the most effective combination in inducing apoptosis in the cell lines. Increased caspase-3 and PARP cleavage were noted in the cell lines when they were treated with romidepsin and mTOR inhibitors. RNA sequencing analysis of Mel202 cells revealed that apoptosis was the most affected pathway in the romidepsin/AZD-8055-treated cells. Increases in pro-apoptotic BCL2L11 and decreases in anti-apoptotic BIRC5 and BCL2L1 transcripts noted in the sequencing analysis were confirmed at the protein level in Mel202 cells.

Conclusions

Our data suggest that romidepsin in combination with mTOR inhibition could be an effective treatment strategy against uveal melanoma due in part to changes in apoptotic proteins.

Traditional Chinese medicine Bu-Shen-Jian-Pi-Fang attenuates glycolysis and immune escape in clear cell renal cell carcinoma: results based on network pharmacology

Clear cell renal cell carcinoma (ccRCC) is the most common malignant type of kidney cancer. The present study aims to explore the underlying mechanism and potential targets of the traditional Chinese medicine Bu-Shen-Jian-Pi-Fang (BSJPF) in the treatment of ccRCC based on network pharmacology. After obtaining the complete composition information for BSJPF from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform, we analyzed its chemical composition and molecular targets and then established a pharmacological interaction network. Twenty-four significantly differentially expressed genes and nine pathways mainly related to tumor proliferation were identified and screened. Functional enrichment analysis indicated that the potential targets might be significantly involved in glycolysis and the HIF-1 signaling pathway. To further confirm the effect of BSJPF on ccRCC cell proliferation, a BALB/c xenograft mouse model was constructed. Potential targets involved in regulating glycolysis and the tumor immune microenvironment were evaluated using RT-qPCR. VEGF-A expression levels were markedly decreased, and heparin binding-EGF expression was increased in the BSJPF group. BSJPF also inhibited tumor proliferation by enhancing GLUT1- and LDHA-related glycolysis and the expression of the immune checkpoint molecules PD-L1 and CTLA-4, thereby altering the immune-rejection status of the tumor microenvironment. In summary, the present study demonstrated that the mechanism of BSJPF involves multiple targets and signaling pathways related to tumorigenesis and glycolysis metabolism in ccRCC. Our research provides a novel theoretical basis for the treatment of tumors with traditional Chinese medicine and new strategies for immunotherapy in ccRCC patients.

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.

Hexokinase 3 dysfunction promotes tumorigenesis and immune escape by upregulating monocyte/macrophage infiltration into the clear cell renal cell carcinoma microenvironment

Purpose: This study aimed to identify the potential prognostic role of HK3 and provide clues about glycolysis and the microenvironmental characteristics of ccRCC. Methods: Based on the Cancer Genome Atlas (TCGA, n = 533) and Gene expression omnibus (GEO) (n = 127) databases, real-world (n = 377) ccRCC cohorts, and approximately 15,000 cancer samples, the prognostic value and immune implications of HK3 were identified. The functional effects of HK3 in ccRCC were analyzed in silico and in vitro. Results: The large-scale findings suggested a significantly higher HK3 expression in ccRCC tissues and the predictive efficacy of HK3 for tumor progression and a poor prognosis. Next, the subgroup survival and Cox regression analyses showed that HK3 serves as a promising and independent predictive marker for the prognosis and survival of patients with ccRCC from bioinformatic databases and real-world cohorts. Subsequently, we found that HK3 could be used to modulate glycolysis and the malignant behaviors of ccRCC cells. The comprehensive results suggested that HK3 is highly correlated with the abundance of immune cells, and specifically stimulates the infiltration of monocytes/macrophages presenting surface markers, regulates the immune checkpoint molecules PD-1 and CTLA-4 of exhaustive T cells, restrains the immune escape of tumor cells, and prompts the immune-rejection microenvironment of ccRCC. Conclusion: In conclusion, the large-scale data first revealed that HK3 could affect glycolysis, promote malignant biologic processes, and predict the aggressive progression of ccRCC. HK3 may stimulate the abundance of infiltrating monocytes/macrophages presenting surface markers and regulate the key molecular subgroups of immune checkpoint molecules of exhaustive T cells, thus inducing the microenvironmental characteristics of active anti-tumor immune responses.

Modulation of lactate-lysosome axis in dendritic cells by clotrimazole potentiates antitumor immunity

BACKGROUND

Dendritic cells (DCs) play a critical role in antitumor immunity, but the therapeutic efficacy of DC-mediated cancer vaccine remains low, partly due to unsustainable DC function in tumor antigen presentation. Thus, identifying drugs that could enhance DC-based antitumor immunity and uncovering the underlying mechanism may provide new therapeutic options for cancer immunotherapy.

METHODS

In vitro antigen presentation assay was used for DC-modulating drug screening. The function of DC and T cells was measured by flow cytometry, ELISA, or qPCR. B16, MC38, CT26 tumor models and C57BL/6, Balb/c, nude, and Batf3-/- mice were used to analyze the in vivo therapy efficacy and impact on tumor immune microenvironment by clotrimazole treatment.

RESULTS

By screening a group of small molecule inhibitors and the US Food and Drug Administration (FDA)-approved drugs, we identified that clotrimazole, an antifungal drug, could promote DC-mediated antigen presentation and enhance T cell response. Mechanistically, clotrimazole acted on hexokinase 2 to regulate lactate metabolic production and enhanced the lysosome pathway and Chop expression in DCs subsequently induced DC maturation and T cell activation. Importantly, in vivo clotrimazole administration induced intratumor immune infiltration and inhibited tumor growth depending on both DCs and CD8+ T cells and potentiated the antitumor efficacy of anti-PD1 antibody.

CONCLUSIONS

Our findings showed that clotrimazole could trigger DC activation via the lactate-lysosome axis to promote antigen cross-presentation and could be used as a potential combination therapy approach to improving the therapeutic efficacy of anti-PD1 immunotherapy.

FAT10 promotes the progression of bladder cancer by upregulating HK2 through the EGFR/AKT pathway

The ubiquitin-like protein FAT10 and the hexokinase protein HK2 play vital regulatory roles in several cellular processes. However, the relationship between these two proteins and their role in the pathogenesis of bladder cancer are not well understood. Here, we found that FAT10 and HK2 protein levels were markedly higher in bladder cancer tissues than in normal adjacent tissues. In addition, RNAi-mediated silencing of FAT10 led to reduced HK2 levels and suppressed bladder cancer progression in vivo and in vitro. The results of our in vivo and in vitro experiments revealed that HK2 is critical for FAT10-mediated progression of bladder cancer. The current study demonstrated that FAT10 enhanced the progression of bladder cancer by positively regulating HK2 via the EGFR/AKT pathway. Based on our findings, FAT10 is believed to stabilize EGFR expression by modulating its degradation and ubiquitination. The results of the current study indicate that there is a correlation between FAT10 and HK2 in the progression of bladder cancer. In addition, we identified a new pathway that may be involved in the regulation of HK2. These findings implicate dysfunction of the FAT10, EGFR/AKT, and HK2 regulatory circuit in the progression of bladder cancer.

Automated in vivo screen in zebrafish identifies Clotrimazole as targeting a metabolic vulnerability in a melanoma model

Therapeutic approaches for cutaneous melanoma are flourishing, but despite promising results, there is an increasing number of reported primary or secondary resistance to the growing sets of drugs approved for therapy in the clinics. Combinatorial approaches may overcome resistance, as they may tackle specific weaknesses of melanoma cells, not sufficient on their own, but effective in combination with other therapies. The transgenic zebrafish line kita:ras develops melanoma with high frequency. At 3 dpf, transgenic kita:ras larvae show a hyperpigmentation phenotype as earliest evidence of abnormal melanocyte growth. Using this model, we performed a chemical screen based on automated detection of a reduction of melanocyte number caused by any of 1280 FDA or EMA approved drugs of the library. The analysis showed that 55 molecules were able to reduce by 60% or more the number of melanocytes per embryo. We further tested two compounds for each of the 5 classes, and a farnesyltransferase inhibitor (Lonafarnib), that inhibits an essential post-translational modification of HRAS and suppresses the hyperpigmentation phenotype. Combinations of Clotrimazole and Lonafarnib showed the most promising results in zebrafish embryos, allowing a dose reduction of both drugs. We performed validation of these observations in the metastatic human melanoma cell line A375M, and in normal human epithelial melanocytes (NHEM) in order to investigate the mechanism of action of Clotrimazole in blocking the proliferation of transformed melanocytes. Viability assay and analysis of energy metabolism in Clotrimazole treated cells show that this drug specifically affects melanoma cells in vitro and transformed melanocytes in vivo, having no effects on NHEM or wild type larvae. Similar effects were observed with another hit of the same class, Miconazole. Furthermore, we show that the effects of Clotrimazole are mediated by the inhibition of hexokinase activity, which is lethal to the abnormal metabolic profile of melanoma cells in vitro and in vivo. Thus, our study shows that the zebrafish can provide a phenotype-rich assay for fully automated screening approaches to identify drugs for synthetic lethal treatment in melanoma and suggest further testing of Clotrimazole in combinatorial treatments.

Dioscin Inhibited Glycolysis and Induced Cell Apoptosis in Colorectal Cancer via Promoting c-myc Ubiquitination and Subsequent Hexokinase-2 Suppression

Purpose

Dioscin is a natural product isolated from traditional Chinese medicines and is reported to have antitumor activities against several cancers. In the present study, we aimed to investigate its potency against colorectal cancers, especially the effects on tumor glycolysis, and to elaborate related molecular mechanisms.

Methods

The antitumor activities of dioscin were evaluated by cell proliferation assays and colony formation assays in vitro and the mouse xenograft models in vivo. The effects of dioscin on tumor glycolysis were determined by measuring glucose absorption and lactate generation. Cell apoptosis was detected by cleaved PARP and the activity of caspase-3. Protein overexpression or gene knockdown was conducted to illustrate molecular mechanisms. Immunoprecipitation experiments were applied to identify the interaction between different proteins.

Results

Dioscin substantially inhibited colorectal cancer cell proliferation in vitro and suppressed the xenograft growth in nude mice. After dioscin treatment, with the suppression of hexokinase-2, the tumor glycolysis was significantly decreased. Dioscin substantially impaired the interaction between hexokinase-2 and VDAC-1, and induced cell apoptosis. Exogenous overexpression of hexokinase-2 significantly antagonized the glycolysis suppression and apoptosis induction by dioscin. Through enhancing the binding of E3 ligase FBW7 to c-myc, dioscin promoted the ubiquitination of c-myc and gave rise to c-myc degradation, which contributed to the inhibition of hexokinase-2.

Conclusion

Our studies revealed a novel mechanism by which dioscin exerted its antitumor activity in colorectal cancer, and verified that dioscin or its analog might have potentials for colorectal cancer therapy.

Histone Deacetylases and their Inhibitors in Cancer Epigenetics

Histone deacetylases (HDAC) and histone deacetylase inhibitors (HDACi) have greatly impacted the war on cancer. Their role in epigenetics has significantly altered the development of anticancer drugs used to treat the most rare, persistent forms of cancer. During transcription, HDAC and HDACi are used to regulate the genetic mutations found in cancerous cells by removing and/or preventing the removal of the acetyl group on specific histones. This activity determines the relaxed or condensed conformation of the nucleosome, changing the accessibility zones for transcription factors. These modifications lead to other biological processes for the cell, including cell cycle progression, proliferation, and differentiation. Each HDAC and HDACi class or group has a distinctive mechanism of action that can be utilized to halt the progression of cancerous cell growth. While the use of HDAC- and HDACi-derived compounds are relatively new in treatment of cancers, they have a proven efficacy when the appropriately utilized. This following manuscript highlights the mechanisms of action utilized by HDAC and HDACi in various cancer, their role in epigenetics, current drug manufacturers, and the impact predicative modeling systems have on cancer therapeutic drug discovery.

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.