Phosphatase of regenerating liver-3 inhibits invasiveness and proliferation in non-small cell lung cancer by regulating the epithelial-mesenchymal transition

Protein Tyrosine Phosphatase PRL-3: A Key Player in Cancer Signaling

Protein phosphatases are primarily responsible for dephosphorylation modification within signal transduction pathways. Phosphatase of regenerating liver-3 (PRL-3) is a dual-specific phosphatase implicated in cancer pathogenesis. Understanding PRL-3's intricate functions and developing targeted therapies is crucial for advancing cancer treatment. This review highlights its regulatory mechanisms, expression patterns, and multifaceted roles in cancer progression. PRL-3's involvement in proliferation, migration, invasion, metastasis, angiogenesis, and drug resistance is discussed. Regulatory mechanisms encompass transcriptional control, alternative splicing, and post-translational modifications. PRL-3 exhibits selective expressions in specific cancer types, making it a potential target for therapy. Despite advances in small molecule inhibitors, further research is needed for clinical application. PRL-3-zumab, a humanized antibody, shows promise in preclinical studies and clinical trials. Our review summarizes the current understanding of the cancer-related cellular function of PRL-3, its prognostic value, and the research progress of therapeutic inhibitors.

Negative regulators of Wnt signaling in non-small cell lung cancer: Theoretical basis and therapeutic potency

Significant advances in the treatment of non-small cell lung cancer (NSCLC) have been made over the past decade, and they predominantly involve molecular targets such as epidermal growth factor receptor (EGFR) mutations and anaplastic lymphoma kinase (ALK) rearrangements. However, despite the initial good response, drug resistance eventually develops. The Wnt signaling pathway has recently been considered important in embryonic development and tumorigenesis in many cancers, particularly NSCLC. Moreover, the aberrant Wnt pathway plays a significant role in NSCLC and is associated with cancer cell proliferation, metastasis, invasion and drug resistance, and the suppression of canonical or noncanonical Wnt signaling through various biological or pharmacological negative regulators has been proven to produce specific anticancer effects. Thus, blocking the Wnt pathway via its negative regulators may overcome the resistance of current treatment methods and lead to new treatment strategies for NSCLC. Therefore, in this review, we summarize recent studies on the role of negative regulators in Wnt signaling in NSCLC and the therapeutic potency of these molecules as agents and targets for NSCLC treatments.

P4HA3 is Epigenetically Activated by Slug in Gastric Cancer and its Deregulation is Associated With Enhanced Metastasis and Poor Survival

Prolyl 4-hydroxylase alpha subunit is the enzymic active site of prolyl 4-hydroxylase, which is a critical enzyme to maintain the stability of newly synthesized collagens. The expression profile and functional role of P4HA3 in gastric cancer have not been explored. In the Cancer Genome Atlas-Stomach Cancer, P4HA3 RNA is significantly upregulated in gastric cancer than in normal stomach tissues. In the Human Protein Atlas, Prolyl 4-hydroxylase alpha subunit is not detectable by immunohistochemistry staining in normal stomach tissues, but it has weak staining in 7 of 12 gastric cancer tissues. Further study showed that SNAI2 (encoding Slug) is highly coexpressed with P4HA3 (Pearson r = 0.70) in Cancer Genome Atlas-Stomach Cancer. In vitro cell assay showed that Slug could efficiently bind to the P4HA3 promoter and increase its transcription. P4HA3 exon array data in Cancer Genome Atlas-Stomach Cancer revealed that 2 exons are significantly upregulated in M1 (N = 27) cases than in M0 (N = 367) cases. In MKN-45 and AGS cells, P4HA3 upregulation could enhance cell motility and invasiveness. In Cancer Genome Atlas-Stomach Cancer, high P4HA3 exon expression is associated with significantly worse 5-year and 10-year overall survival (P = .007 and .009, respectively). Data mining in Kaplan-Meier plotter also showed that high P4HA3 expression is related to unfavorable overall survival (hazard ratio: 1.54, 95% confidence interval: 1.23-1.93, P < .001) and first progression-free survival (hazard ratio: 1.64, 95% confidence interval: 1.29-2.1, P < .001). Based on findings above, we infer that P4HA3 is epigenetically activated by Slug, and its deregulation is associated with enhanced metastasis and poor survival of gastric cancer.

Matrine inhibits the invasive and migratory properties of human hepatocellular carcinoma by regulating epithelial‑mesenchymal transition

Matrine has been reported to be an effective anti-tumor therapy; however, the anti-metastatic effects of matrine on hepatocellular carcinoma (HCC) and the molecular mechanism(s) involved remain unclear. Therefore, the aims of the present study were to evaluate the effects of matrine on hepatoma and to determine the associated mechanism(s) involved. In the present study, matrine was confirmed to prevent the proliferation of HCC cells and it was observed that matrine also inhibited the migratory, and invasive capabilities of HCC at non-toxic concentrations. Additionally, matrine increased epithelial-cadherin expression and decreased the expression levels of vimentin, matrix metalloproteinase (MMP)2, MMP9, zinc finger protein SNAI1 and zinc finger protein SNAI2. These results indicate that the anti-metastatic effect of matrine may be associated with epithelial-mesenchymal transition (EMT). Furthermore, matrine can increase phosphatidylinositol 3,4,5-trisphosphate 3-phosphatase and dual-specificity protein phosphatase PTEN (PTEN) expression and reduce phosphorylated-protein kinase B (Akt) levels. In conclusion, these results suggested that matrine is a potential therapeutic agent that can suppress cancer-associated invasion and migration via PTEN/Akt-dependent inhibition of EMT.

MicroRNA-187 modulates epithelial-mesenchymal transition by targeting PTRF in non-small cell lung cancer

MicroRNAs (miRNAs) that negatively regulate gene expression play a key role in the development and progression of cancer. Aberrant expression of hsa-miR-187 (miR-187) has been reported in various malignancies. However, the function of miR-187 in tumor progression remains controversial and its role in non-small cell lung cancer (NSCLC) is poorly understood. In the present study, the role of miR-187 in the progression of NSCLC was investigated. Our results revealed that miR-187 was frequently upregulated in NSCLC tissues and cells. Furthermore, ectopic introduction of miR-187 promoted cell migration, whereas miR-187 inhibitor had the contrary effect in NSCLC cells. Of significance, miR-187 induced epithelial-mesenchymal transition (EMT), which plays a pivotal role in the initiation of metastasis and activated mitogen-activated protein kinase (MAPK) and phosphatidylinositol-3-kinase/protein kinase B (PI3K/AKT) pathways. Polymerase I and transcript release factor (PTRF) was identified as a direct target of miR-187 in the promotion of the migration of NSCLC cells. Restored expression of PTRF neutralized the promoting effect of miR-187 on cell migration and EMT of NSCLC cells. Collectively, our data highlight the pivotal role of miR-187 in the progression of NSCLC, indicating this factor as a potential candidate in molecular cancer therapy.

The Functional Haplotypes of CHRM3 Modulate mRNA Expression and Associate with Bladder Cancer among a Chinese Han Population in Kaohsiung City

Bladder cancer is one of the major cancer types and both environmental factors and genetic background play important roles in its pathology. Kaohsiung is a high industrialized city in Taiwan, and here we focused on this region to evaluate the genetic effects on bladder cancer. Muscarinic acetylcholine receptor M3 (CHRM3) was reported as a key receptor in different cancer types. CHRM3 is located at 1q42-43 which was reported to associate with bladder cancer. Our study attempted to delineate whether genetic variants of CHRM3 contribute to bladder cancer in Chinese Han population in south Taiwan. Five selected SNPs (rs2165870, rs10802789, rs685550, rs7520974, and rs3738435) were genotyped for 30 bladder cancer patients and 60 control individuals and genetic association studies were performed. Five haplotypes (GTTAT, ATTGT, GCTAC, ACTAC, and ACCAC) were found significantly associated with low CHRM3 mRNA level and contributed to increased susceptibility of bladder cancer in Kaohsiung city after rigid 10000 consecutive permutation tests. To our knowledge, this is the first genetic association study that reveals the genetic contribution of CHRM3 gene in bladder cancer etiology.

Cathepsin L upregulation-induced EMT phenotype is associated with the acquisition of cisplatin or paclitaxel resistance in A549 cells

AIM

Cathepsin L (CTSL), a lysosomal acid cysteine protease, is known to play important roles in tumor metastasis and chemotherapy resistance. In this study we investigated the molecular mechanisms underlying the regulation of chemoresistance by CTSL in human lung cancer cells.

METHODS

Human lung cancer A549 cells, A549/PTX (paclitaxel-resistant) cells and A549/DDP (cisplatin-resistant) cells were tested. The resistance to cisplatin or paclitaxel was detected using MTT and the colony-formation assays. Actin remodeling was observed with FITC-Phalloidin fluorescent staining or immunofluorescence. A wound-healing assay or Transwell assay was used to assess the migration or invasion ability. The expression of CTSL and epithelial and mesenchymal markers was analyzed with Western blotting and immunofluorescence. The expression of EMT-associated transcription factors was measured with Western blotting or q-PCR. BALB/c nude mice were implanted subcutaneously with A549 cells overexpressing CTSL, and the mice were administered paclitaxel (10, 15 mg/kg, ip) every 3 d for 5 times.

RESULTS

Cisplatin or paclitaxel treatment (10-80 ng/mL) induced CTSL expression in A549 cells. CTSL levels were much higher in A549/PTX and A549/DDP cells than in A549 cells. Silencing of CTSL reversed the chemoresistance in A549/DDP and A549/TAX cells, whereas overexpression of CTSL attenuated the sensitivity of A549 cells to cisplatin or paclitaxel. Furthermore, A549/DDP and A549/TAX cells underwent morphological and cytoskeletal changes with increased cell invasion and migration abilities, accompanied by decreased expression of epithelial markers (E-cadherin and cytokeratin-18) and increased expression of mesenchymal markers (N-cadherin and vimentin), as well as upregulation of EMT-associated transcription factors Snail, Slug, ZEB1 and ZEB2. Silencing of CTSL reversed EMT in A549/DDP and A549/TAX cells; In contrast, overexpression of CTSL induced EMT in A549 cells. In xenograft nude mouse model, the mice implanted with A549 cells overexpressing CTSL exhibited significantly reduced sensitivity to paclitaxel treatment, and increased expression of EMT-associated proteins and transcription factors in tumor tissues.

CONCLUSION

Cisplatin and paclitaxel resistance is associated with CTSL upregulation-induced EMT in A549 cells. Thus, CTSL-mediated EMT may be exploited as a target to enhance the efficacy of cisplatin or paclitaxel against lung cancer and other types of malignancies.