Cell survival and apoptosis-related molecules in cancer cells in effusions: A comprehensive review

The potential therapeutic effects of Galbanic acid on cancer

Galbanic acid (GBA), as a natural compound has potential anticancer properties. It has been documented that GBA shows promising therapeutic potential against various types of cancer, including breast, lung, colon, liver, and prostate cancer. Several mechanisms involve im anti-tumor effects of GBA include apoptosis induction, cell cycle arrest, inhibition of angiogenesis, suppression of metastasis, and modulation of immune responses. Furthermore, the synergistic effects of GBA along with chemotherapeutic agents led to has enhancing efficiency with reduction in toxicity. Moreover, GBA through antioxidant and anti-inflammatory properties possess indirect anti-tumor effects. In this review, we will summarize the anti-tumor effects of GBA acid along with involve mechanisms.

Targeting the Overexpressed YY1 in Cancer Inhibits EMT and Metastasis

There have been recent developments in the treatment of various cancers, in particular non-metastatic cancers. However, many of the responding patients often relapse initially through the development of spread micro and macro-metastases. Unfortunately, there are very few therapeutic modalities for the treatment of metastatic cancers. The development of cancer metastasis has been proposed to involve the epithelial-mesenchymal transition (EMT), in which the tumor cells with the EMT phenotype exhibit various phenotypic markers and molecular modifications that are manifested to resist most conventional therapies. YY1 is a target of the hyperactivated nuclear factor-kappa beta pathway in cancer and it was reported that YY1 also regulates cell survival and cell proliferation in addition to its role in EMT and resistance. The overexpression of YY1 in the majority of cancers has been correlated with poor prognosis. It is hypothesized that targeting YY1 may result in several anti-tumor activities, including inhibition of cell survival and cell proliferation, inhibition of EMT, and reversal of resistance. This review discusses the potential therapeutic targeting of an overexpressed transcription factor, Yin Yang 1 (YY1), which has been implicated in the development of EMT and drug resistance. Several examples targeting YY1 in experimental models are presented.

HSP47 is associated with the prognosis of laryngeal squamous cell carcinoma by inhibiting cell viability and invasion and promoting apoptosis

Heat shock protein 47 (HSP47) is a 47 kDa collagen binding protein that has a close relationship with the development and progression of tumours. However, little is known concerning the expression profile of HSP47 in laryngeal squamous cell carcinoma (LSCC) patients and there is still insufficient data concerning the underlying mechanisms. The aim of the present study was to explore the expression of HSP47 in LSCC and provide an overview of its association with tumourigenicity and clinical prognosis. The expression of HSP47 in LSCC and adjacent non-cancerous laryngeal tissues was assessed via western blotting and immunohistochemical studies. The prognostic significance of HSP47 expression was analysed using a Kaplan-Meier survival curve. To investigate the influence of HSP47 on the viability, invasion and apoptosis of a LSCC cell line, we performed an in vitro analysis with plasmid vectors and small interfering RNA (siRNA). Our results showed that HSP47 protein expression in the LSCC tissues was markedly decreased compared to that noted in the adjacent non-cancerous tissues, and low expression of HSP47 was correlated with poor prognosis in LSCC patients. Upregulation of HSP47 via plasmid vectors inhibited the proliferation, reduced the invasive ability, increased the sensitivity to cisplatin chemotherapy, promoted apoptosis, and induced the G1 phase arrest of LSCC cells in vitro. The expression of apoptosis-regulating proteins was also altered when HSP47 was upregulated, involving increased expression of cleaved caspase-7/-8/-9, PARP, and Bax and decreased expression of Bcl-2. Our present data suggest that HSP47 is an important prognostic factor and an attractive therapeutic target in LSCC due to its influence on the biological behaviour of LSCC cells.

Reactive oxygen species dependent phosphorylation of the liver kinase B1/AMP activated protein kinase/ acetyl-CoA carboxylase signaling is critically involved in apoptotic effect of lambertianic acid in hepatocellular carcinoma cells

Though lambertianic acid (LA) is reported to have hypolipidemic activity in liver, its underlying anticancer mechanism is poorly understood so far. Thus, in the present study, apoptotic mechanism of LA was elucidated in HepG2 and SK-Hep1 hepatocellular carcinoma (HCC) cells. Here LA increased cytotoxicity, sub-G1 population and Annexin V/PI positive cells in two HCC cells. Also, LA cleaved caspase-3 and poly(ADP-ribose) polymerase (PARP), activated phosphorylation of liver kinase B1 (LKB1)/AMP activated protein kinase (AMPK)/ acetyl-CoA carboxylase (ACC) pathway and also suppressed antiapoptotic proteins such as phosphorylation of Akt/ mammalian target of rapamycin (mTOR) and the expression of B cell lymphoma-2 (Bcl-2)/ B-cell lymphoma-extra large (Bcl-xL) and cyclooxygenase-2 (COX-2) in two HCC cells. Furthermore, LA generated reactive oxygen species (ROS) in HepG2 cells and AMPK inhibitor compound C or ROS inhibitor N-acetyl-L-cysteine (NAC) blocked the apoptotic ability of LA to cleave PARP or increase sub G1 population in HepG2 cells. Consistently, cleavages of PARP and caspase-3 were induced by LA only in AMPK^+/+ MEF cells, but not in AMPK^-/- MEF cells. Also, immunoprecipitation (IP) revealed that phosphorylation of LKB1/AMPK through their binding was enhanced in LA treated HepG2 cells. Overall, these findings suggest that ROS dependent phosphorylation of LKB1/AMPK/ACC signaling is critically involved in LA induced apoptosis in HCCs.

Nitric oxide-mediated sensitization of resistant tumor cells to apoptosis by chemo-immunotherapeutics

The generation of NO by the various NO synthases in normal and malignant tissues is manifested by various biological effects that are involved in the regulation of cell survival, differentiation and cell death. The role of NO in the cytotoxic immune response was first revealed by demonstrating the induction of iNOS in target cells by immune cytokines (e.g. IFN-γ, IL-1, TNF-α, etc.) and resulting in the sensitization of resistant tumor cells to death ligands-induced apoptosis. Endogenous/exogenous NO mediated its immune sensitizing effect by inhibiting NF-κΒ activity and downstream, inactivating the repressor transcription factor YY1, which inhibited both Fas and DR5 expressions. In addition, NO-mediated inhibition of NF-κΒ activity and inhibition downstream of its anti-apoptotic gene targets sensitized the tumor cells to apoptosis by chemotherapeutic drugs. We have identified in tumor cells a dysregulated pro-survival/anti-apoptotic loop consisting of NF-κB/Snail/YY1/RKIP/PTEN and its modification by NO was responsible, in large, for the reversal of chemo and immune resistance and sensitization to apoptotic mechanisms by cytotoxic agents. Moreover, tumor cells treated with exogenous NO donors resulted in the inhibition of NF-κΒ activity via S-nitrosylation of p50 and p65, inhibition of Snail (NF-κΒ target gene), inhibition of transcription repression by S-nitrosylation of YY1 and subsequent inhibition of epithelial-mesenchymal transition (EMT), induction of RKIP (inhibition of the transcription repressor Snail), and induction of PTEN (inhibition of the repressors Snail and YY1). Further, each gene product modified by NO in the loop was involved in chemo-immunosensitization. These above findings demonstrated that NO donors interference in the regulatory circuitry result in chemo-immunosensitization and inhibition of EMT. Overall, these observations suggest the potential anti-tumor therapeutic effect of NO donors in combination with subtoxic chemo-immuno drugs. This combination acts on multiple facets including reversal of chemo-immune resistance, and inhibition of both EMT and metastasis.

Apoptotic Effect of Galbanic Acid via Activation of Caspases and Inhibition of Mcl-1 in H460 Non-Small Lung Carcinoma Cells

Galbanic acid (GBA), a major compound of Ferula assafoetida, was known to have cytotoxic, anti-angiogenic and apoptotic effects in prostate cancer and murine Lewis lung cancer cells; the underling apoptotic mechanism of GBA still remains unclear so far. Thus, in the present study, the apoptotic mechanism of GBA was investigated mainly in H460 non-small cell lung carcinoma (NSCLC) cells because H460 cells were most susceptible to GBA than A549, PC-9 and HCC827 NSCLC cells. Galbanic acid showed cytotoxicity in wild EGFR type H460 and A549 cells better than other mutant type PC-9 and HCC827 NSCLC cells. Also, GBA significantly increased the number of Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) positive cells and sub G1 population in H460 cells. Western blotting revealed that GBA cleaved poly (ADP-ribose) polymerase (PARP), activated Bax and caspase 9, attenuated the expression of Bcl-2, Bcl-x(L), and Myeloid cell leukemia 1 (Mcl-1) in H460 cells. However, interestingly, overexpression of Mcl-1 blocked the ability of GBA to exert cytotoxicity, activate caspase9 and Bax, cleave PARP, and increase sub G1 accumulation in H460 cells. Overall, these findings suggest that GBA induces apoptosis in H460 cells via caspase activation and Mcl-1 inhibition in H460 cells as a potent anticancer agent for NSCLC treatment.

Activation of caspases and inhibition of ribosome biogenesis mediate antitumor activity of Chijongdan in A549 non-small lung cancer cells

Background

Though herbal medicines have been used for cancer prevention and treatment, their scientific evidences still remain unclear so far. Thus, complementary and alternative medicine (CAM) project has been actively executed to reveal the scientific evidences in the USA and other countries. In the present study, we elucidated antitumor mechanism of Chijongdan, an oriental prescription of Rhus verniciflua, processed Panax ginseng, Persicaria tinctoria and Realgar, that has been traditionally applied for cancer treatment in Korea.

Methods

Chijongdan was prepared with extracts of Rhus verniciflua, processed Panax ginseng, Persicaria tinctoria and processed Realgar. The cytotoxicity of Chijongdan was measured by MTT colorimetric assay. Cell cycle analysis was performed by FACS. Western blot was performed to see the apoptosis related proteins.

Results

Chijongdan significantly exerted cytotoxicity in A549, H460 and H1299 non-small cell lung carcinoma (NSCLC) cells by MTT assay and also increased the number of ethidium homodimer positively stained cells in A549 NSCLC cells. Also, cell cycle analysis showed that Chijongdan increased sub-G1 population in a concentration dependent manner in A549 cells. In addition, Western blotting revealed that Chijongdan activated cleaved PARP, and caspase 9/3, while attenuated the expression of survival genes such as Bcl-2, Bcl-_XL and survivin in A549 cells. Furthermore, Chijongdan suppressed the expression of ribosomal biogenesis related proteins such as upstream binding factor (UBF), Fibrillarin, NPM (B23) and Importin-7 (IPO7) and conversely pan-caspase inhibitor Z--VAD-FMK reversed the apoptotic ability of Chijongdan to cleave PARP and caspase 3 and attenuate the expression of UBF and Fibrillarin in A549 cells.

Conclusions

These findings suggest that Chijongdan induces apoptosis and inhibits ribosomal biogenesis proteins via caspase activation.

The crude extract of Corni Fructus induces apoptotic cell death through reactive oxygen species-modulated pathways in U-2 OS human osteosarcoma cells

Crude extract of Corni Fructus (CECF) has been used in Traditional Chinese medicine for the treatment of different diseases for hundreds of years. The purpose of this study was to investigate the cytotoxic effects of CECF on U-2 OS human osteosarcoma cells. Flow cytometry was used for measuring the percentage of viable cells, cell-cycle distribution, apoptotic cells in sub-G1 phase, reactive oxygen species (ROS), Ca(2+) levels, and mitochondrial membrane potential (ΔΨm ). Comet assay and 4'-6-diamidino-2-phenylindole staining were used for examining DNA damage and condensation. Western blotting was used to examine apoptosis-associated protein levels in U-2 OS cells after exposed to CECF. Immunostaining and confocal laser system microscope were used to examine protein translocation after CECF incubation. CECF decreased the percentage of viability, induced DNA damage and DNA condensation, G₀/G₁ arrest, and apoptosis in U-2 OS cells. CECF-stimulated activities of caspase-8, caspase-9, and caspase-3, ROS, and Ca(2+) production, decreased ΔΨm levels of in U-2 OS cells. CECF increased protein levels of caspase-3, caspase-9, Bax, cytochrome c, GRP78, AIF, ATF-6α, Fas, TRAIL, p21, p27, and p16 which were associated with cell-cycle arrest and apoptosis. These findings suggest that CECF triggers apoptosis in U-2 OS cells via ROS-modulated caspase-dependent and -independent pathways.

Laminarin-induced apoptosis in human colon cancer LoVo cells

A number of scientific studies have revealed that laminarin has antitumor effects. Therefore, the aim of the present study was to investigate the apoptosis of LoVo cells and the underlying mechanisms induced by laminarin. LoVo cells were treated with various concentrations of laminarin and fluorescence-inverted microscopy was used to observe the morphology of LoVo cells treated with laminarin. In addition, western blotting was performed to analyze the expression levels of death receptor (DR)4, DR5, TNF-related apoptosis-inducing ligand (TRAIL), Fas-associated protein with death domain (FADD), caspase-8, caspase-3, Bid and tBid. Flow cytometry was conducted to analyze the expressions of Bcl-2 and Bax, and spectrophotometry was performed to quantify the activity of caspases-8, -3, -6 and -7. Following the treatment of LoVo cells with laminarin for 24 h, the expression levels of DR4, DR5, TRAIL, FADD, Bid, tBid and Bax were observed to be upregulated, whereas the expression levels of pro-caspase-8, pro-caspase-3 and Bcl-2 were downregulated. In addition, the activities of casapse-8, -3, -6 and -7 were observed to increase, which was a significant difference when compared with those of the control group. Therefore, laminarin is considered to induce the apoptosis of LoVo cells, which may occur via a DR pathway, suggesting that laminarin may be a potent agent for cancer treatment.

Activin and inhibin, estrogens and NFκB, play roles in ovarian tumourigenesis is there crosstalk?

Ovarian cancer may be the most frequently lethal gynaecological malignancy but the heterogeneous nature of the disease and the advanced stage at which it is usually diagnosed, have contributed to the paucity of information relating to its aetiology and pathogenesis. Members of the TGF-β superfamily, estrogen and NFκB have all been implicated in the development and progression of cancers from a wide range of tissues. In the ovary, TGF-β superfamily members and estrogen play key roles in maintaining normal function. To date, little is known about the capacity of NFκB to influence normal ovarian function except that it is ubiquitously expressed. In this review we will highlight the roles that inhibin/activin, estrogen and NFκB, have been attributed within carcinogenesis and examine the potential for crosstalk between these pathways in ovarian cancer pathogenesis.

Dual role of NO donors in the reversal of tumor cell resistance and EMT: Downregulation of the NF-κB/Snail/YY1/RKIP circuitry

Several studies have implicated the role of Nitric Oxide (NO) in the regulation of tumor cell behavior and have shown that NO either promotes or inhibits tumorigenesis. These conflicting findings have been resolved, in part, by the levels of NO used such that low levels promote tumor growth and high levels inhibit tumor growth. Our studies have focused on the use of high levels of NO provided primarily by the NO donor, DETANONOate. We have shown that treatment of resistant tumor cells with DETANONOate sensitizes them to apoptosis by both chemotherapeutic drugs and cytotoxic immunotherapeutic ligands. The underlying mechanisms by which NO sensitizes tumor cells to apoptosis were shown to be regulated, in part, by NO-mediated inhibition of the NF-κB survival/anti-apoptotic pathways and downstream of NF-κB by inhibition of the transcription factor Yin Yang 1 (YY1). In addition to NO-induced sensitization to apoptosis, we have also shown that NO induced the expression of the metastasis-suppressor/immunosurveillance cancer gene product, Raf-1 kinase inhibitor protein (RKIP). Overexpression of RKIP mimics NO in tumor cells-induced sensitization to apoptosis. The induction of RKIP by NO was the result of the inhibition of the RKIP repressor, Snail, downstream of NF-κB. These findings established the presence of a dysregulated NF-κB/Snail/YY1/ RKIP circuitry in resistance and that treatment with NO modifies this loop in tumor cells in favor of the inhibition of tumor cell survival and the response to cytotoxic drugs. Noteworthy, the NF-κB/Snail/YY1/RKIP loop consists of gene products that regulate the epithelial to mesenchymal transition (EMT) and, thus, tumor metastasis. Hence, we have found that treatment of metastatic cancer cell lines with DETANONOate inhibited the EMT phenotype, through both the inhibition of the metastasis-inducers, NF-κB and Snail and the induction of the metastasis-suppressor, RKIP. Altogether, the above findings establish, for the first time, the dual role of high levels of NO in the sensitization of tumor cells to apoptotic stimuli as well as inhibition of EMT. Hence, NO donors may be considered as novel potential therapeutic agents with dual roles in the treatment of patients with refractory cancer and in the prevention of the initiation of the metastatic cascade via EMT.