The endoplasmic reticulum stress marker, glucose-regulated protein-78 (GRP78) in visceral adipocytes predicts endometrial cancer progression and patient survival

Expression and significance of glucose-regulated protein 78 in human osteosarcoma

The present study aimed to investigate the expression of glucose-regulated protein 78 (GRP78) in osteosarcoma cells, and analyze the differences in expression between tumor and normal tissues, pre- and post-chemotherapy patients and metastatic and non-metastatic tumors. According to these results, the associations between the expression of GRP78 and tumor growth, metastasis and chemotherapeutics could be determined. Between 2007 and 2012, 60 patients who had been diagnosed with osteosarcoma were selected for the present study. Of these patients, 20 presented with non-metastatic tumors and 40 with metastatic tumors, and 20 had been treated without chemotherapy and 40 with chemotherapy. In addition, 60 specimens obtained from adjacent normal tissues were collected for the control groups. Immunofluorescence staining was used to examine the expression of GRP78 in the different tissues. The total RNA and protein were extracted from crushed tissues and used in the reverse transcription polymerase chain reaction and western blot analysis. GRP78 was primarily located in the intracavity of the endoplasmic reticulum. The expression level of GRP78 in the tumor tissue was higher than that in the normal tissue surrounding the tumor (P<0.01). In addition, the level was higher in the metastatic tumors compared with the non-metastatic tumors (P<0.05), and in the non-chemotherapy-treated patients compared with the chemotherapy-treated patients (P<0.01). The expression level of GRP78 mRNA in the tumor tissue was higher than that in the normal tissue (P<0.01). Furthermore, the level was higher in the metastasis group than in the non-metastasis group (P<0.05), and in the non-chemotherapy group than in the chemotherapy group (P<0.01). The expression level of GRP78 protein was higher in the tumor tissue compared with the normal tissue (P<0.01), in the metastasis group compared with the non-metastasis group (P<0.05), and in the non-chemotherapy group compared with the chemotherapy group (P<0.01). In conclusion, the present study detected the expression of GRP78 in patients with osteosarcoma and revealed a higher expression level in the tumor tissues compared with the normal tissues around the tumor, in the metastasis group compared with the non-metastasis group and in the non-chemotherapy-treated group compared with the chemotherapy-treated group.

Targeting the glucose-regulated protein-78 abrogates Pten-null driven AKT activation and endometrioid tumorigenesis

Rates of the most common gynecologic cancer, endometrioid adenocarcinoma (EAC), continue to rise, mirroring the global epidemic of obesity, a well-known EAC risk factor. Thus, identifying novel molecular targets to prevent and/or mitigate EAC is imperative. The prevalent Type 1 EAC commonly harbors loss of the tumor suppressor, Pten, leading to AKT activation. The major endoplasmic reticulum (ER) chaperone, GRP78, is a potent pro-survival protein to maintain ER homeostasis, and as a cell surface protein, is known to regulate the PI3K/AKT pathway. To determine whether targeting GRP78 could suppress EAC development, we created a conditional knockout mouse model utilizing progesterone receptor (PR)-Cre-recombinase to achieve Pten and Grp78 (cPten^f/fGrp78^f/f) deletion in the endometrial epithelium. Mice with a single Pten (cPten^f/f) deletion developed well-differentiated EAC by 4 weeks. In contrast, no cPten^f/fGrp78^f/f mice developed EAC, even after more than 8 months of observation. Histologic examination of uteri from cPten^f/fGrp78^f/f mice also revealed no complex atypical hyperplasia (CAH), a well-established EAC precursor. These histologic observations among the cPten^f/fGrp78^f/f murine uteri also corresponded to abrogation of AKT activation within the endometrium. We further observed that GRP78 co-localized with activated AKT on the surface of EAC thus providing an opportunity for therapeutic targeting. Consistent with previous findings that cell surface GRP78 is an upstream regulator of PI3K/AKT signaling, we show here that in vivo short-term systemic treatment with a highly specific monoclonal antibody against GRP78 suppressed AKT activation and increased apoptosis in the cPten^f/f tumors. Collectively, these findings present GRP78-targeting therapy as an efficacious therapeutic option for EAC.

Glucose-regulated protein 78 and heparanase expression in oral squamous cell carcinoma: correlations and prognostic significance

BACKGROUND

The aim of the present study was to investigate the expression of glucose-related protein 78 (GRP78) and heparanase (HPA) in oral squamous cell carcinoma (OSCC) and their relationship with clinicopathological parameters and potential implications for survival.

METHODS

A total of 46 patients with OSCC and 10 normal individuals were recruited for the study. GRP78 and HPA expression were determined in the lesion tissues using immunohistochemical analysis. The correlation between GRP78 and HPA was assessed using the Spearman correlation analysis. The associations of GRP78 and HPA with clinicopathological characteristics and survival were examined using the x2-test, Kaplan-Meier, or Cox regression.

RESULTS

Patients with OSCC showed a statistically significant higher prevalence of GRP78 and HPA expression than normal oral tissues. GRP78 and HPA expression was positively correlated with size, TNM stage, histological grade, lymphatic metastasis, and distant metastasis in OSCC patients. GRP78 expression was also positively correlated with HPA expression. Positive GRP78 and HPA expression was inversely correlated with survival in OSCC patients.

CONCLUSIONS

HPA expression was found to be positively correlated with GRP78 expression. GRP78 and HPA are biomarkers that may have the potential to guide the treatment of oral cancer patients.

Effect of overexpression of glucose-regulated protein 78 and bcl-2 on recurrence and survival in patients with ureter tumors

PURPOSE

The utility of the expression of glucose-regulated protein 78 (GRP78) in the evaluation of prognosis depends on the type of tumor. Hence, we aimed to examine the impact of expression of GRP78 and Bcl-2, which are used in the existing prognostic evaluation of ureter tumors, in the evaluation of recurrence and survival rates of ureter tumors.

MATERIALS AND METHODS

In 53 patients who had undergone radical nephroureterectomy for a ureter tumor from March 2002 to March 2012, age, sex, T stage, nuclear grade, bladder recurrence, and survival rate were analyzed at the time of the patient's surgery depending on the extent of immunohistochemical expression of GRP78 and Bcl-2.

RESULTS

GRP78 was overexpressed in 25 patients (47.2%). When GRP78 was overexpressed, there was a high T stage (p=0.001) and nuclear grade (p=0.007) and a lot of bladder recurrence (40.0%, p=0.034). Bcl-2 was overexpressed in 16 patients (30.1%), and there were no significant associations with any risk factors (p>0.05, respectively). In the multivariate analysis regarding bladder recurrence, the recurrence rate was higher with higher pT stage (p=0.048) and when GRP78 (p=0.033) was overexpressed. In the Kaplan-Meier survival analysis, although the survival rate was significantly lower in the group in which GRP78 was overexpressed (p=0.03), there was no correlation between Bcl-2 overexpression and survival rate (p=0.07).

CONCLUSIONS

Patients with ureter tumors who had overexpression of GRP78 had a high T stage and nuclear grade, a lot of bladder recurrence, and a low survival rate. Therefore, if GRP78 is overexpressed in ureter tumor patients, active postoperative follow-up should be carried out.

A new curcumin analogue exhibits enhanced antitumor activity in nasopharyngeal carcinoma

The aim of the present study was to evaluate the antitumor effects of the curcumin analogue GL63 on radioresistant nasopharyngeal carcinoma (NPC) CNE2R cells and parental CNE2 cells. The cell viability and proliferation of NPC cells were detected by MTT assay and colony formation assay. The suppressive effect on tumor growth was examined using in vivo subcutaneously inoculated NPC tumor models using nude mice. The cell cycle distribution was detected using flow cytometry. Apoptosis was examined by Hoechst 33342 and Annexin V/PI staining assay. The protein expression of endoplasmic reticulum (ER) stress pathway markers, XBP-1, ATF-4 and CHOP, were examined by western blotting. A growth inhibitory effect was observed following treatment with GL63 in a dose-dependent manner and was more potent when compared to curcumin. GL63 at 5 µM induced significant G2/M arrest and apoptosis in NPC. The tumor-suppressive activity of GL63 in NPC xenograft models was more potent when compared to curcumin. Furthermore, GL63 induced an ER stress response, upregulation of CHOP, XBP-1 and ATF-4 expression, while the same concentration of curcumin had no effect on ER stress. These results suggest that GL63 has more potent antitumor activity than curcumin, which is associated with activation of ER stress, induction of G2/M arrest and apoptosis in NPC cells.