The role of p53 protein and MMP-2 tumor/stromal cells expression on progressive growth of ovarian neoplasms

A-24, a steroidal saponin from Allium chinense, induced apoptosis, autophagy and migration inhibition in p53 wild-type and p53-deficient gastric cancer cells

Allium chinense is a vegetable with nutrition and unique flavor, and it is used as traditional Chinese medicine. We previously reported that the active compound A-24 induces apoptosis and autophagy in p53 wild-type gastric cancer cells through the PI3K/Akt/mTOR pathway. Our present work indicates that A-24 also has a significant proliferation inhibition effect on p53-deficient KATO-III cells, and the p53 status did not affect A-24 induced migration inhibition, but negatively controlled the occurrence of autophagy. We also found that the accumulation of reactive oxygen species (ROS) mediated A-24 induced apoptosis is p53-independent. Besides, p-Akt was not downregulated by A-24 in p53-deficient gastric cancer cells. Taken together, our results indicate that A-24 induced apoptosis and autophagy via the ROS-PI3K/Akt/mTOR pathway in p53 wild-type gastric cancer cells and through the ROS-mTOR pathway in p53-deficient gastric cancer cells. Our study recommended A-24 as a promising future phytotherapeutic candidate for gastric cancer treatment.

Novel Hybrids of Podophyllotoxin and Coumarin Inhibit the Growth and Migration of Human Oral Squamous Carcinoma Cells

Oral squamous cell carcinoma is the most common malignancy of oral tumor. In this study, two novel hybrids of podophyllotoxin and coumarin were designed using molecular hybridization strategy and synthesized. Pharmacological evaluation showed that the potent compound 12b inhibited the proliferation of three human oral squamous carcinoma cell lines with nanomolar IC₅₀ values, as well as displayed less toxicity on normal cells. Mechanistic studies indicated that 12b triggered HSC-2 cell apoptosis, induced cell cycle arrest, and inhibited cell migration. Moreover, 12b could disturb the microtubule network via binding into the tubulin. It was noteworthy that induction of autophagy by 12b was associated with the upregulation of Beclin1, as well as LC3-II. Furthermore, 12b significantly stimulated the AMPK pathway and restrained the AKT/mTOR pathway in HSC-2 cells. These results indicated that compound 12b was a promising candidate for further investigation.

Down-regulation of JMJD5 suppresses metastasis and induces apoptosis in oral squamous cell carcinoma by regulating p53/NF-κB pathway

The prognosis of oral squamous cell carcinoma (OSCC) patients remains unclear, and a better understanding of the underlying molecular mechanisms is urgently required. Jumonji-C (JmjC) domain-containing protein 5 (JMJD5), renamed KDM8, has been implicated in tumorigenesis, circadian rhythm modulation, embryological development, and osteoclastogenesis. In the present study, we found that JMJD5 was over-expressed in patients with OSCC by real-time quantitative PCR (qPCR), western blot and immunohistochemical assays. When knockdown using small interfering RNA (siRNA) in OSCCs, JMJD5 was exhibited to be important for sustaining cell migration and invasion. JMJD5-knockdown increased E-cadherin expressions, and decreased N-cadherin and Vimentin expression levels in OSCC cells. Further, apoptosis was induced by JMJD5-silence through both the intrinsic and extrinsic pathways, as evidenced by the increased cleavage of Caspase-8/-9/-3 and PARP. Meanwhile, p53 expression levels were also up-regulated by JMJD5-knockdown. Suppressing p53 expressions with its inhibitor, PFTα, blocked apoptotic response in JMJD5-silenced cells. JMJD5 inhibition-induced decrease of nuclear factor-kappaB (NF-κB) was rescued by pifithrin-α (PFTα) pre-treatment. Consistently, over-expressing JMJD5 decreased p53, cleaved Caspase-3 and poly (ADP-ribose) polymerase-1 (PARP-1), whereas increased nuclear NF-κB expressions in OSCC cell lines. More importantly, targeting JMJD5 reduced xenograft tumor growth in vivo through the same molecular mechanisms evidenced in vitro. Thus, the data supplied mechanistic insights into the effects of JMJD5 on the modulation of OSCC development, illustrating that JMJD5 might be an essential prognostic indicator and therapeutic target against OSCC progression.

Enhancement of invadopodia activity in glioma cells by sublethal doses of irradiation and temozolomide

OBJECTIVE

Glioblastoma is the most common primary central nervous system tumor in adults. These tumors are highly invasive and infiltrative and result in tumor recurrence as well as an extremely poor patient prognosis. The current standard of care involves surgery, radiotherapy, and chemotherapy. However, previous studies have suggested that glioblastoma cells that survive treatment are potentially more invasive. The goal of this study was to investigate whether this increased phenotype in surviving cells is facilitated by actin-rich, membrane-based structures known as invadopodia.

METHODS

A number of commercially available cell lines and glioblastoma cell lines obtained from patients were initially screened for the protein expression levels of invadopodia regulators. Gelatin-based zymography was also used to establish their secretory protease profile. The effects of radiation and temozolomide treatment on the glioblastoma cells were then investigated with cell viability, Western blotting, gelatin-based zymography, and invadopodia matrix degradation assays.

RESULTS

The authors’ results show that the glioma cells used in this study express a number of invadopodia regulators, secrete MMP-2, and form functional matrix-degrading invadopodia. Cells that were treated with radiotherapy and temozolomide were observed to show an increase primarily in the activation of MMP-2. Importantly, this also resulted in a significant enhancement in the invadopodia-facilitated matrix-degrading ability of the cells, along with an increase in the percentage of cells with invadopodia after radiation and temozolomide treatment.

CONCLUSIONS

The data from this study suggest that the increased invasive phenotype that has been previously observed in glioma cells posttreatment is mediated by invadopodia. The authors propose that if the formation or activity of these structures can be disrupted, they could potentially serve as a viable target for developing novel adjuvant therapeutic strategies that can be used in conjunction with the current treatment protocols in combatting the invasive phenotype of this deadly disease.

Lysophosphatidic acid signaling in ovarian cancer

Lysophosphatidic acid (LPA) is a bioactive phospholipid that is involved in signal transduction between cells. Plasma and ascites levels of LPA are increased in ovarian cancer patients even in the early stages and thus LPA is considered as a potential diagnostic marker for this disease. This review presents the current knowledge regarding LPA signaling in epithelial ovarian cancer. LPA stimulates proliferation, migration and invasion of ovarian cancer cells through regulation of vascular endothelial growth factor, matrix metalloproteinases, urokinase plasminogen activator, interleukin-6, interleukin-8, CXC motif chemokine ligand 12/CXC receptor 4, COX2, cyclin D1, Hippo-Yap and growth-regulated oncogene α concentrations. In this article, all of these targets and signal pathways involved in LPA influence are described.

Sublethal dose of irradiation enhances invasion of malignant glioma cells through p53-MMP 2 pathway in U87MG mouse brain tumor model

Background

Glioblastoma is a highly lethal neoplasm that frequently recurs locally after radiotherapy, and most of these recurrences originate from near the irradiated target field. In the present study, we identified the effects of radiation on glioma invasion and p53, TIMP-2, and MMP-2 expression through in vitro and in vivo experiments.

Methods

The U87MG (wt p53) and U251 (mt p53) human malignant glioma cell lines were prepared, and the U2OS (wt 53) and Saos2 (del p53) osteosarcoma cell lines were used as p53 positive and negative controls. The four cell lines and p53 knock-downed U87MG cells received radiation (2–6 Gy) and were analyzed for expression of p53 and TIMP-2 by Western blot, and MMP-2 activity was detected by zymography. In addition, the effects of irradiation on directional invasion of malignant glioma were evaluated by implanting nude mice with bioluminescent u87-Fluc in vivo followed by MMP-2, p53, and TIMP-2 immunohisto-chemistry and in situ zymography.

Results

MMP-2 activity and p53 expression increased in proportional to the radiation dose in cell lines with wt p53, but not in the cell lines with del or mt p53. TIMP-2 expression did not increase in U87MG cells. MMP-2 activity decreased in p53 knock-downed U87MG cells but increased in the control group. Furthermore, radiation enhanced MMP-2 activity and increased tumor margin invasiveness in vivo. Tumor cells invaded by radiation overexpressed MMP-2 and p53 and revealed high gelatinolytic activity compared with those of non-radiated tumor cells.

Conclusion

Radiation-induced upregulation of p53 modulated MMP-2 activity, and the imbalance between MMP-2 and TIMP-2 may have an important role in glioblastoma invasion by degrading the extracellular matrix. Bioluminescent “U87-Fluc”was useful for observing tumor formation without sacrifice after implanting tumor cells in the mouse brain. These findings suggest that the radiotherapy involved field for malignant glioma needs to be reconsidered, and that future trials should investigate concurrent pharmacologic therapies that inhibit invasion associated with radiotherapy.

Electronic supplementary material

The online version of this article (doi:10.1186/s13014-015-0475-8) contains supplementary material, which is available to authorized users.

Oxymatrine suppresses proliferation and facilitates apoptosis of human ovarian cancer cells through upregulating microRNA‑29b and downregulating matrix metalloproteinase‑2 expression

Oxymatrine, an alkaloid extracted from medicinal plants of the genus Sophora, has a wide range of pharmacological effects. Previous studies have revealed that oxymatrine can inhibit proliferation and metastasis of tumor cells through reducing matrix metalloproteinase‑2 (MMP‑2) mRNA expression. However, the expression of MMP‑2 in ovarian cancer is significantly higher than that in normal ovaries. Furthermore, the expression of microRNA‑29b (miR‑29b) in ovarian carcinoma is significantly lower than that in normal ovaries. Therefore, MMP‑2 and miR‑29b are tumor suppressor factors involved in ovarian cancer. To evaluate the anti-cancer effects of oxymatrine the OVCAR‑3 ovary cancer cell line was treated with oxymatrine at the concentrations of 0, 0.5, 1 and 2 mg/ml. Assessment of the proliferation and apoptosis of OVCAR‑3 cells showed that oxymatrine had an inhibitory effect on ovarian cancer cells. Furthermore, oxymatrine decreased the protein levels of MMP‑2 and increased the expression levels of miR‑29b in OVCAR‑3 cells. Through transfection of miR‑29b precursor into OVCAR‑3 cells, it was demonstrated that miR‑29b regulated MMP‑2 expression in OVCAR‑3 cells. In addition, anti‑miR‑29b antibodies were used to verify that the apoptotic effect of oxymatrine was due to upregulating miR‑29b and downregulating MMP‑2 expression. These results showed that oxymatrine suppresses the proliferation and facilitates apoptosis of human ovarian cancer cells through upregulating miR‑29b and downregulating MMP‑2 expression.

Catalpol suppresses proliferation and facilitates apoptosis of OVCAR-3 ovarian cancer cells through upregulating microRNA-200 and downregulating MMP-2 expression

Catalpol is expected to possess diverse pharmacological actions including anti-cancer, anti-inflammatory and hypoglycemic properties. Matrix metalloproteinase-2 (MMP-2) is closely related to the pathogenesis of ovarian cancer. In addition, microRNA-200 (miR-200) can modulate phenotype, proliferation, infiltration and transfer of various tumors. Here, OVCAR-3 cells were employed to investigate whether the effect of catalpol (25, 50 and 100 μg/mL) promoted apoptosis of ovarian cancer cells and to explore the potential mechanisms. Our results demonstrate that catalpol could remarkably reduce the proliferation and accelerate the apoptosis of OVCAR-3 cells. Interestingly, our findings show that catalpol treatment significantly decreased the MMP-2 protein level and increased the miR-200 expression level in OVCAR-3 cells. Further, microRNA-200 was shown to regulate the protein expression of MMP-2 in OVCAR-3 cells. It is concluded that catalpol suppressed cellular proliferation and accelerated apoptosis in OVCAR-3 ovarian cancer cells via promoting microRNA-200 expression levels and restraining MMP-2 signaling.

Elevated p53 expression levels correlate with tumor progression and poor prognosis in patients exhibiting esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is the most common histological subtype of esophageal cancer and one of the most aggressive types of malignancy, with a high rate of mortality. Early diagnosis and treatment may improve the prognosis of ESCC and, thus, survival rates. As a significant tumor suppressor, p53 is closely associated with apoptosis and the differentiation of cancer cells. The present study evaluated the expression levels of the p53 protein and the clinical significance in patients presenting with ESCC. The p53 protein expression level of 64 paired ESCC and tumor-adjacent normal tissues was evaluated using western blot analysis. In addition, immunohistochemistry (IHC) was performed to detect the p53 expression level in specimens from 118 paraffin-embedded cancerous tissues. The correlation of the p53 expression level with the clinicopathological parameters and prognosis of the ESCC patients was also analyzed. The p53 protein was identified to be highly expressed in the ESCC tissue, with western blot analysis demonstrating that the expression level of p53 in the cancerous tissue was 1.89 times that of the tumor-adjacent normal tissue (P<0.001); furthermore, IHC indicated that there was a marked positive expression of p53 in the ESCC tissue (49.15%). The expression level of p53 protein was identified to be significantly correlated with the tumor grade (P<0.001), N stage (P=0.010). Additionally, the higher level of p53 expression was found to be associated with a poor survival rate in the ESCC patients (P=0.0404). The univariate analysis showed that the survival time of patients was significantly correlated with the T stage (RR=3.886, P<0.001), N stage (lymph node metastasis; RR=3.620, P<0.001) and TNM stage (RR=3.576, P<0.001). Furthermore, the multivariate analysis revealed that the T stage (RR=3.988, P<0.001) and N stage (RR=4.240, P=0.004) significantly influenced the overall survival of the ESCC patients.

The role of the tumor stroma in ovarian cancer

The tumor microenvironment, consisting of stromal myofibroblasts, endothelial cells, and leukocytes, is growingly perceived to be a major contributor to the pathogenesis and disease progression in practically all cancer types. Stromal myofibroblasts produce angiogenic factors, proteases, growth factors, immune response-modulating proteins, anti-apoptotic proteins, and signaling molecules, and express surface receptors and respond to stimuli initiated in the tumor cells to establish a bi-directional communication network in the microenvironment to promote tumor cell invasion and metastasis. Many of these molecules are candidates for targeted therapy and the cancer stroma has been recently regarded as target for biological intervention. This review provides an overview of the biology and clinical role of the stroma in ovarian cancer.