Targeting lysosomal cysteine protease cathepsin S reveals immunomodulatory therapeutic strategy for oxaliplatin-induced peripheral neuropathy.

Rationale: Oxaliplatin-induced peripheral neuropathy (OIPN) is a common adverse effect that causes delayed treatment and poor prognosis among colorectal cancer (CRC) patients. However, its mechanism remains elusive, and no effective treatment is available. Methods: We employed a prospective cohort study of adult patients with pathologically confirmed stage III CRC receiving adjuvant chemotherapy with an oxaliplatin-based regimen for investigating OIPN. To further validate the clinical manifestations and identify a potential therapeutic strategy, animal models, and in vitro studies on the mechanism of OIPN were applied. Results: Our work found that (1) consistent with clinical findings, OIPN was observed in animal models. Targeting the enzymatic activity of cathepsin S (CTSS) by pharmacological blockade and gene deficiency strategy alleviates the manifestations of OIPN. (2) Oxaliplatin treatment increases CTSS expression by enhancing cytosol translocation of interferon response factor 1 (IRF1), which then facilitates STIM-dependent store-operated Ca2+ entry homeostasis. (3) The cytokine array demonstrated an increase in anti-inflammatory cytokines and suppression of proinflammatory cytokines in mice treated with RJW-58. (4) Mechanistically, inhibiting CTSS facilitated olfactory receptors transcription factor 1 release from P300/CBP binding, which enhanced binding to the interleukin-10 (IL-10) promoter region, driving IL-10 downstream signaling pathway. (5) Serum CTSS expression is increased in CRC patients with oxaliplatin-induced neurotoxicity. Conclusions: We highlighted the critical role of CTSS in OIPN, which provides a therapeutic strategy for the common adverse side effects of oxaliplatin.

Mutant KRAS promotes liver metastasis of colorectal cancer, in part, by upregulating the MEK-Sp1-DNMT1-miR-137-YB-1-IGF-IR signaling pathway.

Although the role of insulin-like growth factor-I receptor (IGF-IR) in promoting colorectal liver metastasis is known, the mechanism by which IGF-IR is upregulated in colorectal cancer (CRC) is not defined. In this study, we obtained evidence that mutant KRAS transcriptionally activates IGF-IR gene expression through Y-box-binding protein (YB)-1 upregulation via a novel MEK-Sp1-DNMT1-miR-137 pathway in CRC cells. The mechanistic link between the tumor suppressive miR-137 and the translational regulation of YB-1 is intriguing because epigenetic silencing of miR-137 represents an early event in colorectal carcinogenesis due to promoter hypermethylation. This proposed signaling axis was further verified by the immunohistochemical evaluations of liver metastases from a cohort of 46 KRAS mutant CRC patients, which showed a significant correlation in the expression levels among Sp1, miR-137, YB-1, and IGF-1R. Moreover, suppression of the expression of YB-1 and IGF-IR via genetic knockdown or the pharmacological inhibition of MEK hampers KRAS-driven colorectal liver metastasis in our animal model studies. From a translational perspective, the identification of this KRAS-driven pathway might provide a mechanistic rationale for the use of a MEK inhibitor as an adjuvant, in combination with standard of care, to prevent the recurrence of colorectal liver metastasis in KRAS mutant CRC patients after receiving liver resection, which warrants further investigation.

4E-BP3 regulates eIF4E-mediated nuclear mRNA export and interacts with replication protein A2.

In nucleus, eIF4E regulates the nucleus export of specific mRNA. In this study, altered 4E-BP3 (eIF4E-binding protein 3) expression resulted in profoundly affected cyclin D1 protein levels, partially due to changes in the cytoplasmic cyclin D1 mRNA levels in both U2OS and MCF7 cells, whereas altered 4E-BP1 expression did not affect eIF4E-mediated cyclin D1 mRNA export. 4E-BP3 also affected a subset of growth promoting mRNAs exported in an eIF4-dependent manner. Furthermore, 4E-BP3 interacted with dephosphorylated RPA2 (replication protein A2). The results indicated 4E-BP3 acts as an inhibitor of eIF4E-mediated mRNA export in the examined cells, and 4E-BP3 inhibition of eIF4E-mediated mRNA export is regulated by the phosphorylation state of RPA2.

[Regaining dignity: the experience and process of reconstructing normal defecation functions through an anal sphincter-saving operation].

BACKGROUND: Resection through an anal sphincter-saving (ASS) operation may affect a low rectal cancer patient'snormal defecation function. The long and complex reconstruction process following such a procedure makes understanding the patient rehabilitation experience necessary in order to develop an effective educational strategy that addresses patient needs. PURPOSE: This study investigated the defecation reconstruction experience of low rectal cancer patients after ASS. METHODS: Researchers used a case study method and purposive sampling. Participants were followed for a period of 6 to 8 months and interviewed between 5 and 7 times. RESULTS: Eleven themes emerged from content analysis. Before temporary colostomy take-down: anal leakage and discomfort, dignity impairment, struggling to locate the contracting muscle, restoring anal strength. After colostomy take-down: loss of defecating control again and damage to peri-anal skin, perceived effects and insistence on persisting with training, faith in effectiveness, trying to comply, trying to restrict medication use, maintaining a hygienic self-image and dignity, promoting quality of life, and a chance to regain a normal life. CONCLUSIONS / IMPLICATIONS: Participants described the rehabilitation exercise as beneficial to controlling the defecation and expressed their intent to continue such. Participant experiences can assist stoma nurses to provide better physical and psychological care to ASS patients.

Deregulated expression of sprouty2 and microRNA-21 in human colon cancer: Correlation with the clinical stage of the disease.

Sprouty protein is a novel feedback regulator involved in downstream inactivation of several growth factor receptor pathways. Sprouty2 (Spry2) protein was shown to be downregulated in human cancers. High levels of microRNA-21 (miRNA-21) expression have been associated with poor survival and poor response to adjuvant chemotherapy in cancer patients. But the effect of Spry2 in human colon cancer remained unknown. Paired tumor and normal mucosa samples from patients were examined for their expression of Spry2 mRNA and miRNA-21 by real-time quantitative RT-PCR analysis. Our results show that Spry2 was downregulated in human colon cancer, and its expression levels were lower in advanced-stage tumors than in early-stage tumors. There was a negative correlation between the expression levels of Spry2 and miRNA-21. Furthermore, overexpression of Spry2 suppressed the growth and migration of colon cancer cells with a concomitant increase in PTEN expression and reduction of Akt and MAPK phosphorylation. Spry2 inhibited the growth and tumorigenesis of colon cancer cells in vivo. Conclusively, we show for the first time that Spry2 expression is downregulated and miRNA-21 is upregulated in the clinical samples of colon cancer, which correlates with clinical stage of disease. Thus, Spry2 functions as a tumor suppressor in colon cancer.

Sprouty2 protein enhances the response to gefitinib through epidermal growth factor receptor in colon cancer cells.

Sprouty2 (Spry2) is known to increase the expression of epidermal growth factor receptors (EGFR) by conjugating with c-Casitas B-lineage lymphoma (C-Cbl) to decrease protein degradation. The effect of Spry2 on the treatment of gefitinib, a tyrosine kinase inhibitor of EGFR, with regards to colon cancer is still unclear. The half maximal inhibitory concentration (IC50) values of gefitinib in six colon cancer cell lines were assessed. HCT116 and C2BBel cells expressed lower levels of Spry2 protein and were less sensitive to gefitinib, whereas HT29 cells that expressed high levels of Spry2 protein were more sensitive to gefitinib. The sensitivity to gefitinib was increased after overexpression of Spry2 in HCT116 cells, whereas it was decreased after Spry2 knockdown in HT29 cells. The levels of both phosphorylated and total EGFR were increased when HCT116 cells ectopically overexpressed Spry2, with concomitant increase in phosphatase and tensin homolog (PTEN) expression. Inhibition of EGFR by cetuximab reduced sensitivity to gefitinib in HCT116 cells overexpressing Spry2. However, knockdown of PTEN or K-ras failed to diminish the effect of Spry2 on gefitinib sensitivity. Of note, Spry2 enhanced the antitumor effect of gefitinib in a xenograft model of HCT116 tumors, which harbored K-ras codon 13 mutation. In conclusion, Spry2 can enhance the response of colon cancer cells to gefitinib by increasing the expression of phosphorylated and total EGFR. These results suggest that Spry2 may be a potential biomarker in predicting the response to anti-EGFR treatment in colon cancer and that it is necessary to conduct clinical studies to incorporate Spry2 into the network of cancer treatment.

Translational up-regulation of Aurora-A in EGFR-overexpressed cancer.

Abnormal expression of Aurora-A and epidermal growth factor receptor (EGFR) is observed in different kinds of cancer and associated with poor prognosis in cancer patients. However, the relationship between Aurora-A and EGFR in tumour development was not clear. In previous reports, we found that EGFR translocates to nucleus to activate Aurora-A expression after EGF treatment in EGFR-overexpressed cells. However, we also observed that not all the EGFR-overexpressed cells have the nuclear EGFR pathway to mediate the Aurora-A expression. In this study, we demonstrated that EGF signalling increased the Aurora-A protein expression in EGFR-overexpressed colorectal cancer cell lines via increasing the translational efficiency. In addition, the overexpression of EGFR was also associated with higher expression of Aurora-A in clinical colorectal samples. Activation of the PI3K/Akt/mTOR and MEK/ERK pathways mediated the effect of EGF-induced translational up-regulation. Besides, only the splicing variants containing exon 2 of Aurora-A mRNA showed increased interaction with the translational complex to synthesize Aurora-A protein under EGF stimulus. Besides, the exon 2 containing splicing variants were the major Aurora-A splicing forms expressed in human colorectal cancers. Taken together, our results propose a novel regulatory mechanism for the abnormal expression of Aurora-A in EGFR-overexpressed cancers, and highlight the importance of alternative 5'-UTR splicing variants in regulating Aurora-A expression. Furthermore, the specific expression of exon 2 containing splicing variants in cancer tissues may serve as a potential target for cancer therapy in the future.

Potent cytotoxic lignans from Justicia procumbens and their effects on nitric oxide and tumor necrosis factor-alpha production in mouse macrophages.

A new lignan glycoside, 4-O-alpha-L-arabinopyranosyl-(1' "-->2' ')-beta-D-apiofuranosyldiphyllin (2), named procumbenoside A, and 11 known compounds were isolated from the whole plant of Justicia procumbens. The structure of 2 was established by spectral analysis and chemical methods. The known compounds justicidin A (1), diphyllin (3), and tuberculatin (4) showed potent cytotoxic effects against a number of cancer cells in vitro. Compounds 1 and 4 also strongly enhanced tumor-necrosis factor-alpha (TNF-alpha) generation from mouse macrophage-like RAW 264.7 cells stimulated with lipopolysaccharide (LPS).