Apoptotic effect of lambertianic acid through AMPK/FOXM1 signaling in MDA-MB231 breast cancer cells

Apoptotic and anti-Warburg effect of Morusin via ROS mediated inhibition of FOXM1/c-Myc signaling in prostate cancer cells

Though Morusin is known to induce apoptotic, antiprolifertaive, and autophagic effects through several signaling pathways, the underlying molecular mechanisms of Morusin still remain unclear until now. To elucidate antitumor mechanism of Morusin, cytotoxicity assay, cell cycle analysis, Western blotting, TUNEL assay, RNA interference, immunofluorescense, immunoprecipitation, reactive oxygen species (ROS) measurement, and inhibitor study were applied in this study. Morusin enhanced cytotoxicity, increased the number of TUNEL positive cells, sub-G1 population and induced the cleavages of PARP and caspase3, attenuated the expression of HK2, PKM2, LDH, c-Myc, and Forkhead Box M1 (FOXM1) along with the reduction of glucose, lactate, and ATP in DU145 and PC3 cells. Furthermore, Morusin disrupted the binding of c-Myc and FOXM1 in PC-3 cells, which was supported by String and cBioportal database. Notably, Morusin induced c-Myc degradation mediated by FBW7 and suppressed c-Myc stability in PC3 cells exposed to MG132 and cycloheximide. Also, Morusin generated ROS, while NAC disrupted the capacity of Morusin to reduce the expression of FOXM1, c-Myc, pro-PARP, and pro-caspase3 in PC-3 cells. Taken together, these findings provide scientific evidence that ROS mediated inhibition of FOXM1/c-Myc signaling axis plays a critical role in Morusin induced apoptotic and anti-Warburg effect in prostate cancer cells. Our findings support scientific evidence that ROS mediated inhibition of FOXM1/c-Myc signaling axis is critically involved in apoptotic and anti-Warburg effect of Morusin in prostate cancer cells.

Anti-Warburg effect via generation of ROS and inhibition of PKM2/β-catenin mediates apoptosis of lambertianic acid in prostate cancer cells

To elucidate the underlying antitumor mechanism of lambertianic acid (LA) derived from Pinus koraiensis, the role of cancer metabolism related molecules was investigated in the apoptotic effect of LA in DU145 and PC3 prostate cancer cells. MTT assay for cytotoxicity, RNA interference, cell cycle analysis for sub G1 population, nuclear and cytoplasmic extraction, lactate, Glucose and ATP assay by ELISA, Measurement of reactive oxygen species (ROS) generation, Western blotting, and immunoprecipitation assay were conducted in DU145 and PC3 prostate cancer cells. Herein LA exerted cytotoxicity, increased sub G1 population and attenuated the expression of pro-Caspase3 and pro-poly (ADP-ribose) polymerase (pro-PARP) in DU145 and PC3 cells. Also, LA reduced the expression of lactate dehydrogenase A (LDHA), glycolytic enzymes such as hexokinase 2 and pyruvate kinase M2 (PKM2) with reduced production of lactate in DU145 and PC3 cells. Notably, LA decreased phosphorylation of PKM2 on Tyr105 and inhibited the expression of p-STAT3, cyclin D1, C-Myc, β-catenin, and p-GSK3β with the decrease of nuclear translocation of p-PKM2. Furthermore, LA disturbed the binding of p-PKM2 and β-catenin in DU145 cells, which was supported by Spearman coefficient (0.0463) of cBioportal database. Furthermore, LA generated ROS in DU145 and PC3 cells, while ROS scavenger NAC (N-acetyl L-cysteine) blocked the ability of LA to reduce p-PKM2, PKM2, β-catenin, LDHA, and pro-caspase3 in DU145 cells. Taken together, these findings provide evidence that LA induces apoptosis via ROS generation and inhibition of PKM2/β-catenin signaling in prostate cancer cells.

Novel Butein Derivatives Repress DDX3 Expression by Inhibiting PI3K/AKT Signaling Pathway in MCF-7 and MDA-MB-231 Cell Lines

Background

Breast cancer is one of the major causes of mortalities noticed in women globally. DDX3 has emerged as a potent target for several cancers, including breast cancer to which currently there are no reported or approved drugs.

Methods

To find effective cancer therapeutics, three compounds were computationally designed tweaking the structure of natural compound butein. These compounds were synthesized and evaluated for their anticancer property in MCF-7 and MDA-MB-231 cell lines targeting DDX3. The in silico molecular docking studies have shown that the compounds have occupied the binding site of the human DDX3 target. Furthermore, to investigate the cell viability effect of 3a, 3b, and 3c on MCF-7 and MDA-MB-231 cell lines, the cell lines were treated with different concentrations of compounds for 24 and 48 h and measured using MTT assay.

Results

The cell viability results showed that the have induced dose dependent suppression of DDX3 expression. Additionally, 3b and 3c have reduced the expression of DDX3 in MCF-7 and MDA-MD-231 cell lines. 3b or 3c treated cell lines increased apoptotic protein expression. Both the compounds have induced the apoptotic cell death by elevated levels of cleaved PARP and cleaved caspase 3 and repression of the anti-apoptosis protein BCL-xL. Additionally, they have demonstrated the G2/M phase cell cycle arrest in both the cell lines. Additionally, 3c decreased PI3K and AKT levels.

Conclusions

Our results shed light on the anticancer ability of the designed compounds. These compounds can be employed as chemical spaces to design new prospective drug candidates. Additionally, our computational method can be adapted to design new chemical scaffolds as plausible inhibitors.

LY‑294002 enhances the chemosensitivity of liver cancer to oxaliplatin by blocking the PI3K/AKT/HIF‑1α pathway

Liver cancer remains one of the leading causes of cancer deaths worldwide. The therapeutic effect of oxaliplatin on liver cancer is often limited by acquired resistance of the cancer cells. Abnormal activation of the PI3K/AKT pathway plays an important role in the acquired resistance of oxaliplatin. The present study investigated the effects of the PI3K inhibitor LY-294002 and AKT inhibitor MK2206 on the chemosensitivity of oxaliplatin-resistant liver cancer cells and the molecular mechanism involved. An oxaliplatin-resistant liver cancer cell line HepG2^R was developed. MTT assay, clone formation experiments, flow cytometry and Annexin V-FITC/PI staining were used to determine the proliferation, cycle and apoptosis of HepG2^R cells when oxaliplatin was combined with LY-294002 or MK2206 treatment. The effects of LY-294002 and MK-2206 on the abnormal activation of PI3K/AKT pathway and hypoxia inducible factor (HIF)-1α protein level in HepG2^R cells were detected using western blotting. The results indicated that the PI3K/AKT pathway is stably activated in HepG2^R cells. Compared with the AKT inhibitor MK2206, the PI3K inhibitor LY-294002 more effectively downregulated the phosphorylation levels of p85, p110α, p110β, p110γ and AKT in the PI3K/AKT pathway in HepG2^R cells, and more effectively inhibited the proliferation of the cells. LY-294002 enhanced the chemotherapy sensitivity of HepG2^R cells to oxaliplatin by inducing G₀/G₁ phase arrest and increasing the proportion of apoptotic cells. In addition, LY-294002 reduced the level of HIF-1α, which is highly expressed in HepG2^R cells. It was concluded that LY-294002 enhanced the chemosensitivity of liver cancer cells to oxaliplatin by inhibiting the PI3K/AKT signaling pathway, which may be related to the inhibition of HIF-1α expression. These findings may have clinical significance for the treatment of oxaliplatin-resistant liver cancer.

A review on chemistry, source and therapeutic potential of lambertianic acid

Lambertianic acid (LA) is a diterpene bioactive compound mainly purified from different species of Pinus. It is an optical isomer of another natural compound daniellic acid and was firstly purified from Pinus lambertiana. LA can be synthesized in laboratory from podocarpic acid. It has been reported to have potential health benefits in attenuating obesity, allergies and different cancers including breast, liver, lung and prostate cancer. It exhibits anticancer properties through inhibiting cancer cell proliferation and survival, and inducing apoptosis, targeting major signalling components including AKT, AMPK, NFkB, COX-2, STAT3, etc. Most of the studies with LA were done using in vitro models, thus warranting future investigations with animal models to evaluate its pharmacological effects such as antidiabetic, anti-inflammatory and neuroprotective effects as well as to explore the underlying molecular mechanisms and toxicological profile. This review describes the chemistry, source, purification and therapeutic potentials of LA and it can therefore be a suitable guideline for any future study with LA.

Silencing of CASC8 inhibits non-small cell lung cancer cells function and promotes sensitivity to osimertinib via FOXM1

In a meta-analysis, the long noncoding RNA cancer susceptibility candidate 8 (CASC8) was found to be a cancer susceptibility gene closely related to lung cancer, but its functions in lung cancer are unknown. In the Cancer Genome Atlas database, the expression of CASC8 was significantly higher in non-small cell lung cancer than in adjacent normal tissues, and high expression of CASC8 was associated with poor prognosis in patients with lung adenocarcinoma. Silencing CASC8 inhibited proliferation, migration, and invasion in non-small cell lung cancer cell lines. Silencing CASC8 also promoted sensitivity to osimertinib through Forkhead box M1 (FOXM1). Therefore, this pathway can be exploited in patients with lung cancer resistant to targeted therapies. Our study revealed for the first time that silencing CASC8 inhibited the proliferation, migration, and invasion of non-small cell lung cancer cells and promoted their sensitivity to osimertinib, suggesting that CASC8 is closely related to the occurrence and development of non-small cell lung cancer. This may provide insight into mechanisms of treatment for non-small cell lung cancer.

An integrative pan-cancer investigation reveals common genetic and transcriptional alterations of AMPK pathway genes as important predictors of clinical outcomes across major cancer types

BACKGROUND

The AMP-activated protein kinase (AMPK) is an evolutionarily conserved regulator of cellular energy homeostasis. As a nexus for transducing metabolic signals, AMPK cooperates with other energy-sensing pathways to modulate cellular responses to metabolic stressors. With metabolic reprogramming being a hallmark of cancer, the utility of agents targeting AMPK has received continued scrutiny and results have demonstrated conflicting effects of AMPK activation in tumorigenesis. Harnessing multi-omics datasets from human tumors, we seek to evaluate the seemingly pleiotropic, tissue-specific dependencies of AMPK signaling dysregulation.

METHODS

We interrogated copy number variation and differential transcript expression of 92 AMPK pathway genes across 21 diverse cancers involving over 18,000 patients. Cox proportional hazards regression and receiver operating characteristic analyses were used to evaluate the prognostic significance of AMPK dysregulation on patient outcomes.

RESULTS

A total of 24 and seven AMPK pathway genes were identified as having loss- or gain-of-function features. These genes exhibited tissue-type dependencies, where survival outcomes in glioma patients were most influenced by AMPK inactivation. Cox regression and log-rank tests revealed that the 24-AMPK-gene set could successfully stratify patients into high- and low-risk groups in glioma, sarcoma, breast and stomach cancers. The 24-AMPK-gene set could not only discriminate tumor from non-tumor samples, as confirmed by multidimensional scaling analyses, but is also independent of tumor, node and metastasis staging. AMPK inactivation is accompanied by the activation of multiple oncogenic pathways associated with cell adhesion, calcium signaling and extracellular matrix organization. Anomalous AMPK signaling converged on similar groups of transcriptional targets where a common set of transcription factors were identified to regulate these targets. We also demonstrated crosstalk between pro-catabolic AMPK signaling and two pro-anabolic pathways, mammalian target of rapamycin and peroxisome proliferator-activated receptors, where they act synergistically to influence tumor progression significantly.

CONCLUSION

Genetic and transcriptional aberrations in AMPK signaling have tissue-dependent pro- or anti-tumor impacts. Pan-cancer investigations on molecular changes of this pathway could uncover novel therapeutic targets and support risk stratification of patients in prospective trials.

microRNA-519d Induces Autophagy and Apoptosis of Human Hepatocellular Carcinoma Cells Through Activation of the AMPK Signaling Pathway via Rab10

Background and Aim

Hepatocellular carcinoma (HCC) is a type of cancer with high mortality rates. The overexpression of microRNA-519d (miR-519d) has been explored in different types of cancers, which could significantly help suppress cancer development. This study aimed to investigate the interaction of miR-519d with its target gene, Rab10, as well as its effects on cell proliferation and autophagy in HCC cells through modulation of the AMPK signaling pathway.

Methods

Microarray analysis was used to analyze the differentially expressed genes in HCC, and the target genes of the screened-out miRNA were predicted and verified. The expression of miR-519d and Rab10, AMPK signaling pathway-related proteins, apoptosis- and autophagy-related proteins was determined by RT-qPCR and Western blot analysis in HCC tissues and cell lines. Lastly, the effects of miR-519d and Rab10 in HCC cell proliferation, apoptosis, and mouse tumour xenograft in vivo were examined through gain- and loss-of-function experiments.

Results

MiR-519d was down-regulated and Rab10 was upregulated in HCC tissues and cell lines. Overexpression of miR-519d decreased the expression of Rab10, mTOR, and Bcl-2, but increased the expression of Bax, Beclin1, Atg5, and p53. Upregulated miR-519d and downregulated Rab10 expression suppressed cell proliferation and induced cell apoptosis and autophagy in HCC cells. Finally, upregulation of miR-519d inhibited tumour growth in vivo.

Conclusion

The result obtained in this study indicates that up-regulation of miR-519d inhibits proliferation and promotes apoptosis and autophagy of HCC cells through activation of the AMPK signaling pathway via downregulating Rab10, which provides a potential target for the treatment of HCC.

Disruption of crosstalk between LX-2 and liver cancer stem-like cells from MHCC97H cells by DFOG via inhibiting FOXM1

Hepatic stellate cell (HSC) line LX-2 is activated by liver cancer stem-like cells (LCSLCs) and produces various cytokines that make up most of the hepatocellular carcinoma (HCC) microenvironment. The new genistein derivative, 7-difluoromethoxyl-5,4'-di-n-octylgenistein (DFOG), shows anticancer effects in multiple malignancies by controlling forkhead box M1 (FOXM1). In this study, we aimed to assess whether DFOG disrupts the crosstalk between human HSC LX-2 cells and LCSLCs. Distinct generations of MHCC97H-derived spheres were obtained with the second generation considered as LCSLCs which displayed enhanced self-renewal ability and elevated expression levels of CD133, CD44, and EpCAM proteins, as well as tumorigenicity, as revealed by colony formation assay in vitro and tumorigenicity assay in vivo. LX-2 and MHCC97H cells were co-cultured with/without DFOG (1, 5, and 10 μM, respectively) using the transwell system. FOXM1 overexpression and/or knockdown were employed for mechanistic investigations. Our results suggested that Co-CM promoted LX-2 cell transformation into liver cancer-associated HSCs. Meanwhile, FOXM1 was up-regulated and the level of hepatocyte growth factor (HGF) was increased in LX-2 cells and in the supernatant after Co-CM stimulation. Sphere and colony formation abilities in MHCC97H cells, and protein levels of CD133, CD44, and EpCAM, were also markedly elevated. DFOG dose-dependently inhibited the above effects, similar to FOXM1 knockdown in LX-2 cells. FOXM1 overexpression reversed the inhibitory effects of DFOG or FOXM1 knockdown or both on LX-2 cell activation and LCSLC feature induction in MHCC97H cells by LCSLC/LX-2 co-culture. This study demonstrated that DFOG disrupts the crosstalk between HSCs and LCSLCs to suppress LCSLC features via down-regulating FOXM1 expression and reducing HGF secretion in HSCs.

AMPK Activation of Apoptotic Markers in Human Breast Cancer Cell Lines with Different p53 Backgrounds: MCF-7, MDA-MB-231 and T47D Cells

Background:

Downregulation of AMPK has been established as a major contributor to carcinogenesis in many types of human cancer. We sought to investigate the influence of activated AMPK on apoptotic markers in human breast cancer cells differing in their p53 status, as well as estrogen receptor status (MCF-7 (p53+ and ER+), MDA-MB-231 (p53 mutant and ER-) and T47D (p53 mutant and ER+)).

Methods:

We examined the effect of AICAR-activated AMPK on PARP cleavage, Bax redistribution, the involvement of intrinsic and extrinsic pathways of apoptosis using selective caspase inhibitors and cell cycle progression and p21 levels.

Results:

PARP cleavage occurred to a greater extent in MCF-7 and MDA-MB-231 cells, whereas Bax translocation was slower in MDA-MB-231 cells. Although there were quantitative differences in the effect of caspase inhibitors, it was clear that AMPK activation predominately affected the intrinsic pathway of apoptosis. Although, p21 was increased in all 3 cell types, there were quantitative and time differences. Apoptosis, as measured by fluorimetry, was increased in all three cell types.

Conclusion:

The impact of AMPK activation was cell type dependent resulting in differential activation of apoptotic markers, confirming that the genetic background of breast cancer may have an influence on the mode of action of AMPK. Thus, different anti-tumour mechanisms may be elicited depending on the cellular genotype.

Regulating the CCNB1 gene can affect cell proliferation and apoptosis in pituitary adenomas and activate epithelial-to-mesenchymal transition

The aim of the present study was to investigate the role and potential regulatory mechanisms of cyclin B1 (CCNB1) in the proliferation, apoptosis and epithelial-to-mesenchymal transition (EMT) in pituitary adenomas. A total of 24 specimens were included in the present study. The expression levels of CCNB1 protein in two normal pituitary and 22 pituitary adenoma tissues were determined by western blotting. CCNB1 was knocked-down by lentiviral-mediated infection of short hairpin RNA (shRNA) in GH3 and MMQ cell lines. The proliferation, cell cycle and apoptosis of GH3 and MMQ cell lines were detected using a Cell Counting Kit-8 and flow cytometer. Reverse transcription-quantitative PCR was utilized to detect the expression level of CCNB1 gene and EMT markers. In the present study, resveratrol (RES) was used as an inhibitor of CCNB1. The protein expression level of CCNB1 in pituitary adenomas was higher than that in normal pituitary tissue, as assessed by western blot analysis. In addition, the expression level of CCNB1 in invasive pituitary adenomas was higher when comparing invasive pituitary adenomas and non-invasive pituitary adenomas. Knockdown of CCNB1 resulted in significant decreases in cell viability and proliferation, arrested cell cycle at the G₂/M phase and increased apoptosis. In addition, knockdown of CCNB1 significantly decreased the expression levels of the mesothelial cell marker N-cadherin (P<0.001), but significantly increased the expression levels of the epithelial cell markers E-cadherin (P<0.01) and p120-catenin (P<0.001). Further analyses identified that RES inhibited the expression level of CCNB1, and RES treatment exhibited a similar effect as CCNB1 shRNA infection. The present study suggested that suppressing the expression level of CCNB1 could regulate the proliferation and apoptosis of pituitary tumor cells and alter the expression level of various EMT markers. In addition, RES treatment could be used as an inhibitor of CCNB1. The present study also identified the molecular mechanisms underlying CCNB1 role in EMT.

Suppression of STAT3 Phosphorylation and RelA/p65 Acetylation Mediated by MicroRNA134 Plays a Pivotal Role in the Apoptotic Effect of Lambertianic Acid

As p300-mediated RelA/p65 hyperacetylation by signal transducers and activators of transcription 3 (STAT3) is critical for NF-κB activation, in the current study, the apoptotic mechanism of lambertianic acid (LA) was explored in relation to STAT3 phosphorylation and RelA/p65 acetylation in MCF-7, DU145, PC-3, and MDA-MB-453 cells. LA significantly increased the cytotoxicity, sub G 1 population, and the cleavage of poly (ADP-ribose) polymerase (PARP) in MDA-MB-453 or PC-3 cells (STAT3 mutant), more than in the MCF-7 or DU145 cells (STAT3 wild). Consistently, LA inhibited the phosphorylation of STAT3 and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and disrupted the interaction between p-STAT3, p300, NF-κB, and RelA/p65 acetylation (Ac-RelA/p65) in the MCF-7 and DU145 cells. Also, LA reduced the nuclear translocation of STAT3 and NF-κB via their colocalization, and also suppressed the protein expression of XIAP, survivin, Bcl-2, Bcl-xL, vascular endothelial growth factor (VEGF), Cox-2, c-Myc and mRNA expression of interleukin 6 (IL-6), and tumor necrosis factor-α (TNF-α) in MCF-7 cells. Conversely, IL-6 blocked the ability of LA to suppress the cytotoxicity and PARP cleavage, while the depletion of STAT3 or p300 enhanced the PARP cleavage of LA in the MCF-7 cells. Notably, LA upregulated the level of miRNA134 and so miRNA134 mimic attenuated the expression of pro-PARP, p-STAT3, and Ac-RelA, while the miRNA134 inhibitor reversed the ability of LA to reduce the expression of Ac-RelA and pro-PARP in MCF-7 cells. Overall, these findings suggest that LA induced apoptosis via the miRNA-134 mediated inhibition of STAT3 and RelA/p65 acetylation.