NK007 helps in mitigating paclitaxel resistance through p38MAPK activation and HK2 degradation in ovarian cancer

Transcriptional regulation and post-translational modifications in the glycolytic pathway for targeted cancer therapy

Cancer cells largely rely on aerobic glycolysis or the Warburg effect to generate essential biomolecules and energy for their rapid growth. The key modulators in glycolysis including glucose transporters and enzymes, e.g. hexokinase 2, enolase 1, pyruvate kinase M2, lactate dehydrogenase A, play indispensable roles in glucose uptake, glucose consumption, ATP generation, lactate production, etc. Transcriptional regulation and post-translational modifications (PTMs) of these critical modulators are important for signal transduction and metabolic reprogramming in the glycolytic pathway, which can provide energy advantages to cancer cell growth. In this review we recapitulate the recent advances in research on glycolytic modulators of cancer cells and analyze the strategies targeting these vital modulators including small-molecule inhibitors and microRNAs (miRNAs) for targeted cancer therapy. We focus on the regulation of the glycolytic pathway at the transcription level (e.g., hypoxia-inducible factor 1, c-MYC, p53, sine oculis homeobox homolog 1, N6-methyladenosine modification) and PTMs (including phosphorylation, methylation, acetylation, ubiquitination, etc.) of the key regulators in these processes. This review will provide a comprehensive understanding of the regulation of the key modulators in the glycolytic pathway and might shed light on the targeted cancer therapy at different molecular levels.

Cryptotanshinone suppresses ovarian cancer via simultaneous inhibition of glycolysis and oxidative phosphorylation

Ovarian cancer is one of the most lethal cancers in female reproductive system due to heterogeneity and lack of effective treatment. Targeting aerobic glycolysis, a predominant energy metabolism of cancer cells has been recognized a novel strategy to overcome cancer cell growth. However, the capability of cancer cells to undergo metabolic reprogramming guarantees their survival even when glycolysis is inhibited. Here in this study, we have shown that Cryptotanshinone (CT), a lipid-soluble bioactive anticancer molecule of Salvia miltiorrhiza, inhibits both glycolysis and oxidative phosphorylation (OXPHOS) in ovarian cancer cells leading to growth suppression and apoptosis induction. Our mechanistic study revealed that CT decreased glucose uptake and lactate production, and inhibited the kinase activity of LDHA and HK2. The molecular docking study showed that CT could directly bind with GLUT1, LDHA, HK2, PKM2 and complex-1. The immunoblotting data showed that CT decreased the expression of aberrantly activated glycolytic proteins includingGLUT1, LDHA, HK2, and PKM2. Besides, we found that CT inhibited mitochondrial ComplexⅠ activity, decreased the ratio of NAD+/NADH, and suppressed the generation of ATP and induced activation of AMPK, which controls energy-reducing processes. These in vitro findings were further validated using xenograft model. The findings of in vivo studies were in line with in vitro studies. Taken together, CT effectively suppressed glycolysis and OXPHOS, inhibited growth and induced apoptosis in ovarian cancer cells both in vitro and in vivo study models.

HK2 contributes to the proliferation, migration, and invasion of diffuse large B-cell lymphoma cells by enhancing the ERK1/2 signaling pathway

Hexokinase 2 (HK2) has been associated with carcinogenic growth in numerous kinds of malignancies as essential regulators during the processing of glucose. This study aimed to explore the effects of HK2 on diffuse large B-cell lymphoma (DLBCL) cells via the ERK1/2 signaling. Expressions of HK2 and ERK1/2 were examined in DLBCL cell lines using quantitative reverse transcription polymerase chain reaction and western blotting. HK2 and ERK1/2 were attenuated through HK2 small-interfering RNA (siRNA) and ERK inhibitor FR180204, respectively, in U2932 and SU-DHL-4 cells. Cell Counting Kit-8, clone formation, transwell, and flow cytometry assays were used in evaluating the effects of HK2 and ERK1/2 on cell proliferation, migration, and apoptosis. Moreover, a xenograft model was created to assess the roles of HK2 in vivo. HK2 and ERK1/2 were evidently up-regulated in DLBCL cell lines. HK2 knockdown and FR180204 markedly suppressed the proliferation and clonogenesis of U2932 and SU-DHL-4 cells and promoted cell apoptosis in vitro. We also found that HK2 silencing suppressed tumor growth in vivo. Notably, HK2 knockdown inactivated the ERK1/2 signaling pathway both in vitro and in vivo. These data indicate that inhibition of HK2 may suppress the proliferation, migration, and invasion of DLBCL cells, partly via inhibiting the ERK1/2 signaling pathway.

PGC-1α participates in tumor chemoresistance by regulating glucose metabolism and mitochondrial function

Chemotherapy resistance is the main reason for the failure of cancer treatment. The mechanism of drug resistance is complex and diverse. In recent years, the role of glucose metabolism and mitochondrial function in cancer resistance has gathered considerable interest. The increase in metabolic plasticity of cancer cells' mitochondria and adaptive changes to the mitochondrial function are some of the mechanisms through which cancer cells resist chemotherapy. As a key molecule regulating the mitochondrial function and glucose metabolism, PGC-1α plays an indispensable role in cancer progression. However, the role of PGC-1α in chemotherapy resistance remains controversial. Here, we discuss the role of PGC-1α in glucose metabolism and mitochondrial function and present a comprehensive overview of PGC-1α in chemotherapy resistance.

Natural products targeting glycolytic signaling pathways-an updated review on anti-cancer therapy

Glycolysis is a complex metabolic process that occurs to convert glucose into pyruvate to produce energy for living cells. Normal cells oxidized pyruvate into adenosine triphosphate and carbon dioxide in the presence of oxygen in mitochondria while cancer cells preferentially metabolize pyruvate to lactate even in the presence of oxygen in order to maintain a slightly acidic micro-environment of PH 6.5 and 6.9, which is beneficial for cancer cell growth and metastasis. Therefore targeting glycolytic signaling pathways provided new strategy for anti-cancer therapy. Natural products are important sources for the treatment of diseases with a variety of pharmacologic activities. Accumulated studies suggested that natural products exhibited remarkable anti-cancer properties both in vitro and in vivo. Plenty of studies suggested natural products like flavonoids, terpenoids and quinones played anti-cancer properties via inhibiting glucose metabolism targets in glycolytic pathways. This study provided an updated overview of natural products controlling glycolytic pathways, which also provide insight into druggable mediators discovery targeting cancer glucose metabolism.

Phenanthroindolizidine Alkaloids Isolated from Tylophora ovata as Potent Inhibitors of Inflammation, Spheroid Growth, and Invasion of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC), representing the most aggressive form of breast cancer with currently no targeted therapy available, is characterized by an inflammatory and hypoxic tumor microenvironment. To date, a broad spectrum of anti-tumor activities has been reported for phenanthroindolizidine alkaloids (PAs), however, their mode of action in TNBC remains elusive. Thus, we investigated six naturally occurring PAs extracted from the plant Tylophora ovata: O-methyltylophorinidine (1) and its five derivatives tylophorinidine (2), tylophoridicine E (3), 2-demethoxytylophorine (4), tylophoridicine D (5), and anhydrodehydrotylophorinidine (6). In comparison to natural (1) and for more-in depth studies, we also utilized a sample of synthetic O-methyltylophorinidine (1s). Our results indicate a remarkably effective blockade of nuclear factor kappa B (NFκB) within 2 h for compounds (1) and (1s) (IC50 = 17.1 ± 2.0 nM and 3.3 ± 0.2 nM) that is different from its effect on cell viability within 24 h (IC50 = 13.6 ± 0.4 nM and 4.2 ± 1 nM). Furthermore, NFκB inhibition data for the additional five analogues indicate a structure–activity relationship (SAR). Mechanistically, NFκB is significantly blocked through the stabilization of its inhibitor protein kappa B alpha (IκBα) under normoxic as well as hypoxic conditions. To better mimic the TNBC microenvironment in vitro, we established a 3D co-culture by combining the human TNBC cell line MDA-MB-231 with primary murine cancer-associated fibroblasts (CAF) and type I collagen. Compound (1) demonstrates superiority against the therapeutic gold standard paclitaxel by diminishing spheroid growth by 40% at 100 nM. The anti-proliferative effect of (1s) is distinct from paclitaxel in that it arrests the cell cycle at the G0/G1 state, thereby mediating a time-dependent delay in cell cycle progression. Furthermore, (1s) inhibited invasion of TNBC monoculture spheroids into a matrigel®-based environment at 10 nM. In conclusion, PAs serve as promising agents with presumably multiple target sites to combat inflammatory and hypoxia-driven cancer, such as TNBC, with a different mode of action than the currently applied chemotherapeutic drugs.

Overexpression of NCAPG in ovarian cancer is associated with ovarian cancer proliferation and apoptosis via p38 MAPK signaling pathway

Background

Non-SMC condensin I complex subunit G (NCAPG), a member of the subunit of condensin complex, is significantly overexpressed in various cancers and involved in the pathogenesis of cancers. However, the roles of NCAPG in ovarian cancer remain unclear.

Methods

The mRNA expression, overall survival, and disease-free survival of NCAPG in ovarian cancer were analyzed by GEPIA and KM plotter database, and the expression levels of NCAPG in OC tissues and cell lines were determined by qPCR and immunohistochemistry analysis. shRNA targeting NCAPG gene (sh-NCAPG) was utilized to knock down NCAPG expression in OVCAR3 and SKOV3 cells. Subsequently, CCK-8 assay, colony formation assay, transwell invasion assay and flow cytometric analysis were performed to detect the effect of NCAPG on OC cell proliferation, apoptosis, and invasion. Finally, western blot assays were performed to detect the mechanism of NCAPG in ovarian cancer.

Results

Analysis using GEPIA and KM plotter database showed NCAPG was upregulated in ovarian cancer and negatively associated with the survival of OC patients. qPCR and immunohistochemistry analysis confirmed it was highly expressed in both ovarian cancer tissues and cells. The silencing of NCAPG inhibited OC cell proliferation and invasion, and induced cell apoptosis. Additionally, flow cytometric analysis revealed that NCAPG knockdown arrested the cell cycle at G2 and S phases. Furthermore, we also found that downregulation of NCAPG could suppress OC cell proliferation and invasion via activating the p38 MAPK signaling pathway.

Conclusion

Our results suggest that NCAPG exhibits an important role in the development and progression of ovarian cancer and implicates NCAPG as a potential therapeutic target in ovarian cancer.

Natural Phytochemicals Derived from Gymnosperms in the Prevention and Treatment of Cancers

The incidence of various types of cancer is increasing globally. To reduce the critical side effects of cancer chemotherapy, naturally derived compounds have been considered for cancer treatment. Gymnosperms are a group of plants found worldwide that have traditionally been used for therapeutic applications. Paclitaxel is a commercially available anticancer drug derived from gymnosperms. Other natural compounds with anticancer activities, such as pinostrobin and pinocembrin, are extracted from pine heartwood, and pycnogenol and enzogenol from pine bark. Gymnosperms have great potential for further study for the discovery of new anticancer compounds. This review aims to provide a rational understanding and the latest developments in potential anticancer compounds derived from gymnosperms.

Hypoxia-induced up-regulation of miR-27a promotes paclitaxel resistance in ovarian cancer

Ovarian cancer (OC) is a malignant tumor with high mortality in women. Although cancer patients initially respond to paclitaxel chemotherapy following surgery, most patients will relapse after 12-24 months and gradually die from chemotherapy resistance. In OC, cancer cells become resistant to paclitaxel chemotherapy under hypoxic environment. The miR-27a has been identified as an oncogenic molecular in ovarian cancer, prostate cancer, liver cancer etc. In addition, the miR-27a is involved in hypoxia-induced chemoresistance in various cancers. However, the role of miR-27a in hypoxia-induced OC resistance remains unclear. The aim of the present study was to investigate the regulatory mechanism of miR-27a in hypoxia-induced OC resistance. The expression of HIF-1α induced Hypoxia overtly up-regulated. At the same time, hypoxia increased viability of Skov3 cells and decreased cell apoptosis when treated with paclitaxel. The expression of the miR-27a was obviously up-regulated under hypoxia and involved in hypoxia-induced paclitaxel resistance. Follow-up experiments portray that miR-27a improved paclitaxel resistance by restraining the expression of APAF1 in OC. Finally, we further elucidated the important regulatory role of the miR-27a-APAF1 axis in OC through in vivo experiments. According to our knowledge, we first reported the regulation of miR-27a in hypoxia-induced chemoresistance in OC, providing a possible target for chemoresistance treatment of OC.

Altered glycolysis results in drug-resistant in clinical tumor therapy

Cancer cells undergo metabolic reprogramming, including increased glucose metabolism, fatty acid synthesis and glutamine metabolic rates. These enhancements to three major metabolic pathways are closely associated with glycolysis, which is considered the central component of cancer cell metabolism. Increasing evidence suggests that dysfunctional glycolysis is commonly associated with drug resistance in cancer treatment, and aberrant glycolysis plays a significant role in drug-resistant cancer cells. Studies on the development of drugs targeting these abnormalities have led to improvements in the efficacy of tumor treatment. The present review discusses the changes in glycolysis targets that cause drug resistance in cancer cells, including hexokinase, pyruvate kinase, pyruvate dehydrogenase complex, glucose transporters, and lactate, as well the underlying molecular mechanisms and corresponding novel therapeutic strategies. In addition, the association between increased oxidative phosphorylation and drug resistance is introduced, which is caused by metabolic plasticity. Given that aberrant glycolysis has been identified as a common metabolic feature of drug-resistant tumor cells, targeting glycolysis may be a novel strategy to develop new drugs to benefit patients with drug-resistance.

Calycosin induces apoptosis via p38‑MAPK pathway‑mediated activation of the mitochondrial apoptotic pathway in human osteosarcoma 143B cells

Previous studies have demonstrated that calycosin is a natural phytoestrogen with a similar structure to estrogen, which can inhibit cell proliferation and induce apoptosis in a variety of tumors. Calycosin exerts potential pharmacological effects on osteosarcoma cells by inducing apoptosis. The aim of the present study was to elucidate the specific molecular mechanism of calycosin-induced apoptosis in osteosarcoma cells. Cell proliferation was determined by an MTT assay. Annexin V/PI and JC-1 staining were used to detect apoptosis and mitochondrial dysfunction, respectively, by flow cytometry. Western blot analysis was used to detect the expression of caspases or mitochondrial proteins. The results revealed that calycosin reduced the cell viability of human osteosarcoma 143B cells, induced apoptosis and increased the loss of mitochondrial membrane potential (MMP). In addition, calycosin increased the expression of the proapoptotic antiapoptotic proteins cleaved caspase-3, cleaved caspase-9, cleaved poly(ADP-ribose) polymerase and Bcl-2-associated X protein (Bax), and decreased the expression of the antiapoptotic proapoptotic protein B-cell lymphoma-2 (Bcl-2), thus altering the Bax/Bcl-2 ratio. In addition, the expression levels of cytochrome c were markedly decreased in the mitochondria and increased in the cytoplasm following calycosin treatment. Furthermore, calycosin treatment induced p38-mitogen-activated protein kinase (MAPK) phosphorylation, whereas the p38-MAPK inhibitor BIRB 796 markedly reversed cell viability, apoptosis and loss of MMP in 143B cells. These results suggested that calycosin inhibited osteosarcoma 143B cell growth via p38-MAPK regulation of mitochondrial-dependent intrinsic apoptotic pathways.

Development of long-circulating lapachol nanoparticles: formation, characterization, pharmacokinetics, distribution and cytotoxicity

Lapachol is an active compound for the treatment of malignant brain glioma. However, its physicochemical properties limit its clinical application. The purpose of this study is to develop a nano-drug delivery system (LPC-LP) loaded with lapachol (LPC), which remarkably prolongs the half-life in the body, and increases the brain intake, therefore, achieving a better anticancer effect in the treatment of glioma. In order to optimize the formulation of liposomes, an orthogonal design was adopted with entrapment efficiency (EE) as the index. The characterization of the optimized formulation was evaluated in vitro. To assess the safety profile and effect of LPC-LP, a rapid and sensitive ultra-fast liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) method was developed for studying the pharmacokinetics and brain distribution of LPC-LP and LPC. Finally, the cytotoxicity of the two preparations on C6 cells was studied by the MTT assay. The results showed that the average particle size of LPC-LP was 85.92 ± 2.35 nm, the EE of liposomes was 92.52 ± 1.81%, and the charge potential was −40.70 ± 9.20 mV. An in vitro release study showed that the release of lapachol from LPC-LP was delayed compared to LPC, indicating that LPC-LP was a sustained and controlled release system. The UPLC-MS/MS method was fully validated in both plasma and brain tissue according to the Food and Drug Administration (FDA) recommended guidelines, and successfully used for quantification of lapachol in vivo. After intravenous administration, LPC-LP prolonged circulation time of lapachol in the body and increased brain intake. Besides, the MTT results revealed that the IC₅₀ value of LPC-LP on C6 cells significantly decreased, compared with LPC, which further confirmed that LPC-LP enhanced the inhibition of C6 cells and improved the anti-glioma effect. In conclusion, LPC-LP could serve as a promising candidate for the clinical application of lapachol in the treatment of glioma.

LPC-LP is a promising and potential nanoparticle in the treatment of glioma.

Licochalcone A-Induced Apoptosis Through the Activation of p38MAPK Pathway Mediated Mitochondrial Pathways of Apoptosis in Human Osteosarcoma Cells In Vitro and In Vivo

BACKGROUND

Licochalcone A (LicA) is isolated from the roots of Glycyrrhiza glabra and possesses antitumor and anti-invasive activities against several tumor cells. However, the antitumor effects of LicA on human osteosarcoma cells have yet to be demonstrated either in vitro or in vivo.

METHODS

Cell viability was measured by MTT assay. Apoptosis and mitochondrial dysfunction were detected with Annexin V/PI staining and JC-1 staining by flow cytometry. The expressions of caspase- or mitochondrial-related proteins were demonstrated by western blotting. Antitumor effect of LicA on 143B xenograft mice in vivo.

RESULTS

LicA could inhibit cell proliferation and induce apoptosis in human osteosarcoma cells, as evidenced by a decrease in cell viability, loss of mitochondrial membrane potentials, and activation of caspases. LicA treatment substantially reduced the expression of Bcl-2 and Mcl-1 and increased the expression of cleaved-caspase-3, cleaved-caspase-9, cleaved-PARP, and Bax in HOS and U2OS cells. Moreover, mitochondrial membrane potential and apoptosis suppression mediated by Z-VAD or tauroursodeoxycholic acid significantly reduced LicA-induced mitochondria-dependent apoptosis. The study also determined that LicA treatment induced p38MAPK phosphorylation, but siRNA-p38 or BIRB796 substantially reversed cell viability through the inhibition of mitochondria-dependent apoptosis pathways. Finally, an in vivo study revealed that LicA significantly inhibited 143B xenograft tumor growth.

CONCLUSIONS

These findings demonstrate that LicA has antitumor activities against human osteosarcoma cells through p38MAPK regulation of mitochondria-mediated intrinsic apoptotic pathways in vitro and in vivo.