mPGES-1 Inhibitor Discovery Based on Computer-Aided Screening: Pharmacophore Models, Molecular Docking, ADMET, and MD Simulations

mPGES-1 is an enzyme, which, when activated by inflammatory factors, can cause prostaglandin E synthesis. Traditional non-steroidal anti-inflammatory drugs are capable of inhibiting prostaglandin production, yet they can also cause gastrointestinal reactions and coagulation disorders. mPGES-1, the enzyme at the conclusion of prostaglandin production, does not cause any adverse reactions when inhibited. Numerous studies have demonstrated that mPGES-1 is more abundant in cancerous cells than in healthy cells, indicating that decreasing the expression of mPGES-1 could be a potential therapeutic strategy for cancer. Consequently, the invention of mPGES-1 inhibitors presents a fresh avenue for the treatment of inflammation and cancer. Incorporating a database of TCM compounds, we collected a batch of compounds that had an inhibitory effect on mPGES-1 and possessed IC50 value. Firstly, a pharmacophore model was constructed, and the TCM database was screened, and the compounds with score cut-off values of more than 1 were retained. Then, the compounds retained after being screened via the pharmacodynamic model were screened for docking at the mPGES-1 binding site, followed by high-throughput virtual screening [HTVS] and standard precision [SP] and super-precision [XP] docking, and the compounds in the top 20% of the XP docking score were selected to calculate the total free binding energy of MM-GBSA. The best ten compounds were chosen by comparing their score against the reference ligand 4U9 and the MM-GBSA_dG_Bind score. ADMET analysis resulted in the selection of ten compounds, three of which had desirable medicinal properties. Finally, the binding energy of the target protein mPGES-1 and the candidate ligand compound was analyzed using a 100 ns molecular dynamics simulation of the reference ligand 4U9 and three selected compounds. After a gradual screening study and analysis, we identified a structure that is superior to the reference ligand 4U9 in all aspects, namely compound 15643. Taken together, the results of this study reveal a structure that can be used to inhibit mPGES-1 compound 15643, thereby providing a new option for anti-inflammatory and anti-tumor drugs.

Treatment with decitabine induces the expression of stemness markers, PD-L1 and NY-ESO-1 in colorectal cancer: potential for combined chemoimmunotherapy

BACKGROUND

The mechanism of tumor immune escape and progression in colorectal cancer (CRC) is widely investigated in-vitro to help understand and identify agents that might play a crucial role in response to treatment and improve the overall survival of CRC patients. Several mechanisms of immune escape and tumor progression, including expression of stemness markers, inactivation of immunoregulatory genes by methylation, and epigenetic silencing, have been reported in CRC, indicating the potential of demethylating agents as anti-cancer drugs. Of these, a chemotherapeutic demethylating agent, Decitabine (DAC), has been reported to induce a dual effect on both DNA demethylation and histone changes leading to an increased expression of target biomarkers, thus making it an attractive anti-tumorigenic drug.

METHODS

We compared the effect of DAC in primary 1076 Col and metastatic 1872 Col cell lines isolated and generated from patients' tumor tissues. Both cell lines were treated with DAC, and the expression of the NY-ESO-1 cancer-testis antigen, the PD-L1 immunoinhibitory marker, and the CD44, Nanog, KLF-4, CD133, MSI-1 stemness markers were analyzed using different molecular and immunological assays.

RESULTS

DAC treatment significantly upregulated stemness markers in both primary 1076 Col and meta-static 1872 Col cell lines, although a lower effect occurred on the latter: CD44 (7.85 fold; ***p = 0.0001 vs. (4.19 fold; *p = 0.0120), Nanog (4.1 fold; ***p < 0.0001 vs.1.69 fold; ***p = 0.0008), KLF-4 (4.33 fold; ***p < 0.0001 vs.2.48 fold; ***p = 0.0005), CD133 (16.77 fold; ***p = 0.0003 vs.6.36 fold; *p = 0.0166), and MSI-1 (2.33 fold; ***p = 0.0003 vs.2.3 fold; ***p = 0.0004), respectively. Interestingly, in the metastatic 1872 Col cells treated with DAC, the expression of both PD-L1 and NY-ESO-1 was increased tenfold (*p = 0.0128) and fivefold (***p < 0.0001), respectively.

CONCLUSIONS

We conclude that the upregulation of both stemness and immune checkpoint markers by DAC treatment on CRC cells might represent a mechanism of immune evasion. In addition, induction of NY-ESO-1 may represent an immuno-therapeutic option in metastatic CRC patients. Finally, the combination of DAC and anti-PD-1/anti-PD-L1 antibodies treatment should represent a potential therapeutic intervention for this group of patients.

mPGES-1 in prostate cancer controls stemness and amplifies epidermal growth factor receptor-driven oncogenicity

There is evidence that an inflammatory microenvironment is associated with the development and progression of prostate cancer (PCa), although the determinants of intrinsic inflammation in PCa cells are not completely understood. Here we investigated whether expression of intrinsic microsomal PGE synthase-1 (mPGES-1) enhanced aggressiveness of PCa cells and might be critical for epidermal growth factor receptor (EGFR)-mediated tumour progression. In PCa, overexpression of EGFR promotes metastatic invasion and correlates with a high Gleason score, while prostaglandin E2 (PGE2) has been reported to modulate oncogenic EGFR-driven oncogenicity. Immunohistochemical studies revealed that mPGES-1 in human prostate tissues is correlated with EGFR expression in advanced tumours. In DU145 and PC-3 cell lines expressing mPGES-1 (mPGES-1(SC) cells), we demonstrate that silencing or 'knock down' of mPGES-1 (mPGES-1(KD)) or pharmacological inhibition by MF63 strongly attenuates overall oncogenic drive. Indeed, mPGES-1(SC) cells express stem-cell-like features (high CD44, β1-integrin, Nanog and Oct4 and low CD24 and α6-integrin) as well as mesenchymal transition markers (high vimentin, high fibronectin, low E-cadherin). They also show increased capacity to survive irrespective of anchorage condition, and overexpress EGFR compared to mPGES-1(KD) cells. mPGES-1 expression correlates with increased in vivo tumour growth and metastasis. Although EGFR inhibition reduces mPGES-1(SC) and mPGES-1(KD) cell xenograft tumour growth, we show that mPGES-1/PGE2 signalling sensitizes tumour cells to EGFR inhibitors. We propose mPGES-1 as a possible new marker of tumour aggressiveness in PCa.

Chemoresistance is associated with Beclin-1 and PTEN expression in epithelial ovarian cancers

The aim of the present study was to investigate the protein expression of the autophagy-related genes, BECN1 and PTEN, and the association with drug resistance in epithelial ovarian cancers. In total, 40 patients with pathologically diagnosed epithelial ovarian cancer were divided into a chemotherapy-sensitive group (n=20) and a chemotherapy-resistant group (n=20), according to the results of the pre- or post-operative normative chemotherapy and the post-operative follow-up. The protein expression of the phosphatase and tensin homolog (PTEN) and the BECN1 gene product, Beclin-1, was analyzed using immunohistochemistry in the 40 patients with ovarian carcinoma. The positive rate of Beclin-1 expression was significantly lower in the resistant group (35.0%) compared with the sensitive group (50.0%). The positive rate of PTEN expression was also significantly lower in the resistant group (30.0%) compared with the sensitive group (65.0%). Furthermore, the differences in the expression rates were revealed to be significant (P<0.05). The expression of Beclin-1 was identified to be positively correlated with the expression of PTEN (rs=0.816; P<0.0001). The low expression of the Beclin-1 and PTEN proteins in the ovarian cancer tissues was revealed to be closely associated with drug resistance. Therefore, Beclin-1 may interact with PTEN to participate in the mechanism of drug resistance and the changes in macrophage activity observed in cases of drug-resistant ovarian cancer.

Autophagy: detection, regulation and its role in cancer and therapy response

PURPOSE

Macroautophagy is a catabolic pathway that degrades cellular components through the lysosomal machinery. Cytoplasmic components are sequestered in double-membrane autophagosomes. They fuse with lysosomes where their cargo is delivered for degradation and recycling. Autophagy acts as a survival mechanism under stress by producing energy and as an intracellular quality management system by clearing damaged organelles like mitochondria and proteins. In this review, the regulation and the role of autophagy in cancer and therapy response are discussed. Furthermore, we will summarize methods for detecting autophagy in vitro and in vivo.

CONCLUSION

During the early and late stages of cancer development, the role of autophagy differs. In the very early stages of carcinogenesis, autophagy has an important function by reducing cancer initiating genetic instability and aberrant protein aggregates as well as promoting anti-cancer immune response. In established malignant tumors autophagy confers resistance against metabolic stress caused by nutrient deprivation and the rapid proliferation of carcinoma cells. This function of autophagy is also important for radiation and chemotherapy resistance in cancer. Our laboratory has found that Neuropilin-2-induced autophagy is a potent mediator of therapy resistance in different cancer types. Autophagy not only promotes the survival of tumor cells, but also leads to autophagic cell death. During dysfunctional apoptosis this form of cell death mainly sensitizes cancer cells for therapy such as ionizing radiation. Therefore, the functions of autophagy during cancer progression and therapy are two-sided and further research is needed to understand these in more detail.

PGE2 signaling and its biosynthesis-related enzymes in cholangiocarcinoma progression

Prostaglandin E2 (PGE2) involves in progression of various chronic inflammation-related cancers including cholangiocarcinoma (CCA). This study aimed to determine the role of PGE2 signaling, its biosynthesis-related enzymes in a clinical prognosis, and their targeted inhibition in CCA progression. The immunohistochemical staining of cyclooxygenase (COX)-1, COX-2, mPGES-1, EP1, and EP4 was examined in CCA tissues, and their expressions were compared with clinicopathological parameters. The effect of PGE2 on levels of its signaling molecules was examined in CCA cell lines using proteome profiler array. The suppression of mPGES-1 using a small-molecule inhibitor (CAY10526) and small interfering RNA (siRNA) was determined for growth and migration ability in CCA cells. The results indicated that strong expressions of COX-1, COX-2, mPGES-1, EP1, and EP4 were found in CCA tissues as 87.5, 47.5, 52.5, 55, and 80 % of frequencies, respectively. High mPGES-1 expression was significantly correlated with tumor stages III-IV (p = 0.001), lymph node metastasis (p = 0.004), shorter survival (p = 0.009), and prognostic indicator of CCA patients (HR = 2.512, p = 0.041). Expressions of COX-1, COX-2, and EP receptors did not correlate with data tested from patients. PGE2 markedly enhanced protein levels of integrinα6, VE-cadherin, Jagged1, and Notch3, and CAY10526 suppressed those protein levels as well as PGE2 production in CCA cells. CAY10526 and siRNA mPGES-1 markedly suppressed mPGES-1 protein levels, growth, and migration abilities of CCA cell lines. In conclusion, PGE2 signaling strongly promotes CCA progression. Therefore, inhibition of PGE2 synthesis by suppression of its biosynthesis-related enzymes could be useful for prevention and treatment of CCA.

The relation of beclin 1 and bcl-2 expressions in high grade prostatic intraepithelial neoplasia and prostate adenocarcinoma: a tissue microarray study

The aim of the present study was to evaluate the expressions of beclin 1 and bcl-2 in prostate cancer (PC) and high grade prostatic intraepithelial neoplasia (HGPIN), and to investigate their relationship with clinicopathological parameters. The study included 30 benign prostatic hyperplasia (BPH), 40 HGPIN and 106 primary PC cases. The expressions of beclin 1 and bcl-2 were assessed semiquantitatively based on both the percentage and intensity of positive staining cells. Beclin 1 was positive in 27 (90%) BPH, 37 (92.5%) HGPIN, and 90 (84.9%) PC cases (p>0.05). Bcl-2 immunostaining was detected in 99 (93.4%) PC, 37 (92.5%) HGPIN, and 9 (30%) BPH cases (p<0.0001). Regarding expression scores, beclin 1 was significantly lower in PC cases than in the HGPIN and BPH groups (p<0.0001), and it was also negatively correlated with Gleason score (p=0.004, r=-0.274). Bcl-2 expression score was significantly higher in PC than in the other groups (p<0.0001), and also positively correlated with Gleason score (p<0.0001, r=0.425). Furthermore, a negative correlation was found between bcl-2 and beclin 1 expression scores in PC cases (p=0.006, r=-0.265). Our results suggest an association between bcl-2 and beclin 1 expressions in malignant transformation of prostate tissue and also in regulating PC cell differentiation, progression and the aggressiveness of PC.

Prognostic value of T cell immunoglobulin mucin-3 in prostate cancer

BACKGROUND

Optimal treatment for prostate cancer remains a challenge worldwide. Recently, T cell immunoglobulin mucin-3 (TIM-3) has been implicated in tumor biology but its contribution prostate cancer remains unclear. The aim of this study was to investigate the role of TIM-3 as a prognostic marker in patients with prostate cancer.

METHODS

TIM-3 protein expression was determined by immunohistochemistry and Western blotting in 137 prostate cancer tumor samples and paired adjacent benign tissue. We also performed cell proliferation assays using 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl- 2H tetrazolium bromide (MTT) and cell invasion assays. The effects of small interfering RNA (siRNA)-mediated knockdown of TIM-3 (TIM-3 siRNA) in two human prostate cancer cell lines were also evaluated.

RESULTS

TIM-3 expression was higher in prostate cancer tissue than in the adjacent benign tissue (P<0.001). High TIM-3 expression was an independent predictor of both recurrence-free survival and progression-free survival. TIM-3 protein was expressed in both prostate cancer cell lines and knockdown suppressed their proliferation and invasion capacity.

CONCLUSIONS

TIM-3 expression is associated with a poor prognosis in prostate cancer. Taken together, our results indicate that TIM-3 is a potential prognostic marker in prostate cancer.