Values of applying white blood cell counts in the prognostic evaluation of resectable colorectal cancer.

The count and classification of white blood cells (WBCs) may be used as prognostic markers in certain types of cancer. The present study investigated the prognostic potential of the counts of WBCs, including lymphocytes (LYs), monocytes (MOs), neutrophils (NEs), eosinophils (EOs) and basophils (BAs), in the prognosis of resectable colorectal cancer. The present study recruited 153 resectable colorectal cancer cases retrospectively, which were pathologically confirmed. All patients were divided into two groups, according to the median value of LY (low LY, ≤1.632x109/l or high LY, >1.632x109/l), MO (low MO, ≤0.330x109/l or high MO, >0.330x109/l), NE (low NE, ≤3.600x109/l or high NE, >3.600x109/l), EO (low EO, ≤0.085x109/l or high EO, >0.085x109/l), BA (low BA, ≤0.010x109/l or high BA, >0.010x109/l), or WBC (low WBC, ≤5.780x109/l or high WBC, >5.780x109/l). To evaluate the alterations in WBC counts following surgery and adjuvant chemotherapy; all samples received oxiplatin and capecitabine (XELOX) for 6­8 cycles or 5­fluorouracil, leucovorin and oxaliplatin (mFOLFOX6) for 10­12 cycles. XELOX included oxaliplatin administered intravenously at a dose of 130 mg/m2 on day 1 and 850­1,250 mg/m2 capecitabine twice daily for days 1­14, repeated every 3 weeks. mFOLFOX6 included oxaliplatin administered intravenously at a dose of 85 mg/m2, 400 mg/m2 leucovorin and 400 mg/m2 5­FU on day 1 followed by 1,200 mg/m2/days continuous infusion for 2 days (in total, 2,400 mg/m2 over 46­48 h), repeated every 2 weeks. The present study investigated the post/pre­treatment of LY, MO, NE, EO, BA and WBC ratios (≤1 indicated that LY, MO, NE, EO, BA and WBC counts were not increased following therapy; whereas, >1 suggested increased counts). Kaplan­Meier curves were constructed to demonstrate overall survival (OS). A multivariate and univariate logistic regression analyses model was employed to identify the independent risk factors. Low pre­treatment BA counts were associated with larger tumor size (>5 cm); pre­treatment BA levels were positively associated with OS. Surgery significantly decreased the count of BAs and increased the count of EOs; whereas, no effect was observed on LYs, MOs, NEs or WBCs. Adjuvant chemotherapy markedly decreased the counts of LY, NE and WBC; whereas, no notable effects on MOs, EOs or BAs were observed. Whole course treatment (surgery combined with adjuvant chemotherapy) significantly decreased the values of LY, NE and WBC; however, increased the value of EO; no effects on the MO or BA counts were observed. An increased post­/pre­treatment NE ratio suggested poorer prognosis. Multivariate Cox regression analysis revealed that sex, tumor size, pre­treatment BA count and the post­/pre­treatment NE ratio were independent prognostic factors affecting OS. The results of the present study suggested that the pre­treatment BA count and post­/pre­treatment NE ratio may be potential prognostic factors for resectable colorectal cancer.

Cantharidin and norcantharidin impair stemness of pancreatic cancer cells by repressing the ß-catenin pathway and strengthen the cytotoxicity of gemcitabine and erlotinib.

Increasing evidence suggests that tumors are composed of a heterogeneous cell population with a small subset of cancer stem cells (CSCs) that sustain tumor formation and growth, and are hypothesized to account for therapeutic resistance. Based on the expression of the surface markers CD44, CD24, and EPCAM, putative CSCs have also been identified in pancreatic cancers. It has been well established that aberrant activation of ß-catenin signaling pathway may contribute to the maintenance of CSCs. Cantharidin is an active constituent of mylabris, a traditional Chinese medicine. In our previous studies, we demonstrated that cantharidin treatment induced phosphorylation of ß-catenin, leading to repression on ß-catenin pathway. Therefore, in the present study, we investigated whether cantharidin and its derivant, norcantharidin, could repress the stemness of pancreatic cancer cells through repression on ß-catenin pathway. By using microarray and flow cytometry, we found that treatment with cantharidin and norcantharidin repressed the expression of CD44, CD24, and EPCAM at both mRNA and protein levels, leading to decreased CD44(+)/CD24(+)/EPCAM(+) proportion, the putative pancreatic CSC subset. Pretreatment with the ß-catenin pathway inhibitor FH535, attenuated the cantharidin- and norcantharidin-induced repression on CD44, CD24, and EPCAM, suggesting cantharidin and its derivant repressed stemness of pancreatic cancer cells in ß-catenin pathway-dependent manner. Furthermore, cantharidin and norcantharidin strengthened the cytotoxicity of gemcitabine and erlotinib, two well established pharmacotherapeutics against pancreatic cancers, indicating cantharidin and norcantharidin could be promising candidates for reversing drug resistance in pancreatic cancers. In conclusion, we presently propose that cantharidin and norcantharidin hold their promise in pancreatic cancer therapy through repression on stemness and strengthening the cytotoxicity of the present therapeutics.

Cantharidin represses invasion of pancreatic cancer cells through accelerated degradation of MMP2 mRNA.

Cantharidin is an active constituent of mylabris, a traditional Chinese medicine, and is a potent and selective inhibitor of protein phosphatase 2A (PP2A) that plays an important role in cell cycle control, apoptosis, and cell-fate determination. In the present study, we found that cantharidin repressed the invasive ability of pancreatic cancer cells and downregulated matrix metalloproteinase 2 (MMP2) expression through multiple pathways, including ERK, JNK, PKC, NF-κB, and ß-catenin. Interestingly, transcriptional activity of the MMP2 promoter increased after treatment with PP2A inhibitors, suggesting the involvement of a posttranscriptional mechanism. By using an mRNA stability assay, we found accelerated degradation of MMP2 mRNA after treatment of cantharidin. Microarray analyses revealed that multiple genes involved in the 3' → 5' decay pathway were upregulated, especially genes participating in cytoplasmic deadenylation. The elevation of these genes were further demonstrated to be executed through ERK, JNK, PKC, NF-κB, and ß-catenin pathways. Knockdown of PARN, RHAU, and CNOT7, three critical members involved in cytoplasmic deadenylation, attenuated the downregulation of MMP2. Hence, we present the mechanism of repressed invasion by cantharidin and other PP2A inhibitors through increased degradation of MMP2 mRNA by elevated cytoplasmic deadenylation.

PP2A inhibitors suppress migration and growth of PANC-1 pancreatic cancer cells through inhibition on the Wnt/ß-catenin pathway by phosphorylation and degradation of ß-catenin.

Cantharidin is an active constituent of mylabris, a traditional Chinese medicine, and presents strong anticancer activity in various cell lines. Cantharidin is a potent and selective inhibitor of serine/threonine protein phosphatase 2A (PP2A). Our previous studies revealed the prospect of application of cantharidin, as well as other PP2A inhibitors, in the treatment of pancreatic cancer. However, the mechanisms involved in the anticancer effect of PP2A inhibitors have not been fully explored. The Wnt/ß­catenin pathway is involved in cell migration and proliferation and participates in the progression of pancreatic cancer. If ß­catenin is phosphorylated and degraded, the Wnt/ß­catenin pathway is blocked. PP2A dephosphorylates ß­catenin and keeps the Wnt/ß­catenin pathway active. In the present study, we found that PP2A inhibitor treatment induced phosphorylation and degradation of ß­catenin. The suppression on the migration and growth of PANC­1 pancreatic cancer cells could be attenuated by pretreatment with FH535, a ß­catenin pathway inhibitor. Microarray showed that PP2A inhibitor treatment induced expression changes in 13 of 138 genes downstream of the ß­catenin pathway. Real­time PCR further confirmed that FH535 attenuated the expression changes induced by PP2A inhibitors in 6 of these 13 candidate genes. These 6 genes, VEGFB, Dkk3, KRT8, NRP1, Cacnalg and WISP2, have been confirmed to participate in the migration and/or growth regulation in previous studies. Thus, the phosphorylation- and degradation-mediated suppression on ß­catenin participates in the cytotoxicity of PP2A inhibitors. Our findings may provide insight into the treatment of pancreatic cancer using a targeting PP2A strategy.

Cantharidin and norcantharidin inhibit the ability of MCF-7 cells to adhere to platelets via protein kinase C pathway-dependent downregulation of α2 integrin.

Cancer metastasis is a highly coordinated and dynamic multistep process in which cancer cells interact with a variety of host cells. Morphological studies have documented the association of circulating tumor cells with host platelets, where a surface coating of platelets protects tumor cells from mechanical trauma and the immune system. Cantharidin is an active constituent of mylabris, a traditional Chinese medicine. Cantharidin and norcantharidin are potent protein phosphatase 2A (PP2A) inhibitors that exhibit in vitro and in vivo antitumor activity against several types of cancer, including breast cancer. We investigated whether cantharidin and norcantharidin could repress the ability of MCF-7 breast cancer cells to adhere to platelets. Using MTT, clone formation, apoptosis, adhesion and wound-healing assays, we found that cantharidin and norcantharidin induced apoptosis and repressed MCF-7 cell growth, adhesion and migration. Moreover, we developed a flow cytometry-based analysis of tumor cell adhesion to platelets. We proved that cantharidin and norcantharidin repressed MCF-7 cell adhesion to platelets through downregulation of α2 integrin, an adhesion molecule present on the surface of cancer cells. The repression of α2 integrin expression was found to be executed through the protein kinase C pathway, the activation of which could have been due to PP2A inhibition.

Growth of the pancreatic cancer cell line PANC-1 is inhibited by protein phosphatase 2A inhibitors through overactivation of the c-Jun N-terminal kinase pathway.

Protein phosphatase 2A (PP2A) is a multimeric serine/threonine phosphatase that can dephosphorylate multiple kinases. It is generally considered to be a cancer suppressor as its inhibition can induce phosphorylation and activation of substrate kinases that mainly accelerate growth. We previously reported that cantharidin, an active constituent of a traditional Chinese medicine, potently and selectively inhibited PP2A, yet efficiently repressed the growth of pancreatic cancer cells through activation of the c-Jun N-terminal kinase (JNK) pathway. This suggested that activation of kinase pathways might also be a potential strategy for cancer therapy. In this study, we have confirmed that the basal activity of the phospatidylinositol 3-kinase (PI3K)/JNK/activator protein 1 (AP-1) pathway promoted pancreatic cancer cell growth when stimulated by growth factors. Interestingly, although treatment with the PP2A inhibitors, cantharidin or okadaic acid (OA), amplified the PI3K-dependent activation of JNK, cell growth was repressed. We therefore hypothesised that a specific level of activity of the JNK pathway might be required to maintain the promitogenic function, as both repression and overactivation of JNK could inhibit cell proliferation. It was found that the JNK-dependent growth inhibition was independent of the activation of AP-1, but dependent on the repression of Akt. Although the PP2A inhibitors triggered overactivation of JNK and inhibited cell growth, excessively activated protein kinase C (PKC) improved cell survival. Combined treatment with a PP2A inhibitor and a PKC inhibitor produced a synergistic effect, which indicates a potentially promising therapeutic approach to pancreatic cancer treatment.