Ras-dependent recruitment of c-Myc for transcriptional activation of nucleophosmin/B23 in highly malignant U1 bladder cancer cells

Implications of c-Myc in the pathogenesis and treatment efficacy of urological cancers

Urological cancers, including prostate, bladder, and renal cancers, are significant causes of death and negatively impact the quality of life for patients. The development and progression of these cancers are linked to the dysregulation of molecular pathways. c-Myc, recognized as an oncogene, exhibits abnormal levels in various types of tumors, and current evidence supports the therapeutic targeting of c-Myc in cancer treatment. This review aims to elucidate the role of c-Myc in driving the progression of urological cancers. c-Myc functions to enhance tumorigenesis and has been documented to increase growth and metastasis in prostate, bladder, and renal cancers. Furthermore, the dysregulation of c-Myc can result in a diminished response to therapy in these cancers. Non-coding RNAs, β-catenin, and XIAP are among the regulators of c-Myc in urological cancers. Targeting and suppressing c-Myc therapeutically for the treatment of these cancers has been explored. Additionally, the expression level of c-Myc may serve as a prognostic factor in clinical settings.

Upregulated NPM1 is an independent biomarker to predict progression and prognosis of oral squamous cell carcinomas in Taiwan

BACKGROUND

Nucleophosmin/nucleoplasmin family 1 (NPM1) has broad physiological functions, such as DNA replication, transcription, ribosome biogenesis, and centrosome replication. This study explored the clinicopathological importance of NPM1 as a prognostic marker for oral squamous cell carcinoma (OSCC).

METHODS

We collected specimens from 96 OSCC, 45 oral epithelial dysplasia (OED), and 29 normal oral mucosa (NOM). NPM1 expression was analyzed via immunohistochemistry. Correlations between NPM1and clinical parameters were analyzed using Student t test, chi-squared test, and Kaplan-Meier product-limit method.

RESULTS

The NPM1 labeling indices (LIs) were significantly higher in OSCCs than in NOM and oral OED. Higher NPM1 expression was significantly correlated with larger tumor size, nodal metastasis, and advanced clinical stage. Multivariate analysis revealed that higher NPM1 LIs were an unfavorable independent factor for survival.

CONCLUSIONS

Upregulated NPM1 is an independent biomarker of poor prognosis and NPM1 inhibitors may be promising in molecular targeted therapy against OSCC.

Anti-cancer Effects of a Chemically Modified miR-143 on Bladder Cancer by Either Systemic or Intravesical Treatment

We developed a novel chemically modified miR-143 (miR-143#12), and with it we investigated the contribution of miR-143 to the pathogenesis of bladder cancer (BC), in which miR-143 is extremely downregulated. Since miR-143 silenced K-RAS and RAS effector-signaling molecules Erk and Akt, we performed the ectopic expression of miR-143 in human BC 253J-BV cells, and we examined the growth inhibition and the mechanism of it in vitro and in orthotopic model mice. As a result, miR-143#12 induced a marked growth inhibition with apoptosis through impairing RAS-signaling networks, including SOS1, which exchanges guanosine diphosphate (GDP)/RAS for active guanosine triphosphate (GTP)/RAS. In the in vivo study, miR-143#12 exhibited a marked anti-tumor activity by either systemic or intravesical administration with polyionic copolymer (PIC) as the carrier, compared with the activity obtained by use of lipofection. These findings raised the possibility that the chemically modified miR-143#12 would be a candidate of microRNA (miRNA) medicine for BC delivered by intravesical infusion.

Oncogene c-fos and mutant R175H p53 regulate expression of Nucleophosmin implicating cancer manifestation

Nucleophosmin (NPM1) is a nucleolar protein that is frequently overexpressed in various types of solid tumors. NPM1 is involved in several cellular processes that might contribute significantly to the increased proliferation potential of cancers. Previous reports suggest that NPM1 expression is highly increased in response to mitogenic and oncogenic signals, the mechanisms of which have not been elucidated extensively. Using constructs incorporating different fragments of the NPM1 promoter upstream to a Luciferase reporter gene, we have identified the minimal promoter of NPM1 and candidate transcription factors regulating NPM1 promoter activity by luciferase reporter assays. We have validated the roles of a few candidate factors at the transcriptional and protein level by quantitative reverse transcriptase PCR, immunoblotting and immunohistochemistry, and explored the mechanism of regulation of NPM1 expression using immunoprecipitation and chromatin immunoprecipitation assays. We show here that the expression of NPM1 is regulated by transcription factor c-fos, a protein that is strongly activated by growth factor signals. In addition, mutant p53 (R175H) overexpression also enhances NPM1 expression possibly through c-myc and c-fos. Moreover, both c-fos and mutant p53 are overexpressed in oral tumor tissues that showed NPM1 overexpression. Collectively, our results suggest that c-fos and mutant p53 R175H positively regulate NPM1 expression, possibly in synergism, that might lead to oncogenic manifestation.

Association between the TACC3 rs798766 Polymorphism and Risk of Urinary Bladder Cancer: A Synthesis Based on Current Evidence

Background

A possible association between the TACC3 rs798766 polymorphism and urinary bladder cancer risk has been indicated in published literature. We performed this meta-analysis as a synthesis of all relevant data to summarize currently available evidence and to provide estimation with increased precision.

Methods

EMBASE, PubMed, Google Scholar, and Wanfang Data were searched. “rs798766” and “urinary bladder cancer” were used as the search terms. A total of 6 eligible studies were identified, in which 8194 cases and 50,165 controls were investigated. Meta-analysis was performed using extracted data. Subgroup analysis by ethnicity was also performed. Population attributable risk (PAR) was calculated.

Results

We found a significant association between rs798766[T] and increased risk of bladder cancer, allelic[T] OR = 1.27, 95%CI = 1.20–1.33. Subgroup analysis by ethnicity revealed similar results, allelic[T] OR = 1.24, 95%CI = 1.17–1.32 in Caucasian subjects and allelic[T] OR = 1.33, 95%CI = 1.21–1.46 in Asian subjects. PAR based on pooled allelic ORs and the frequency of the risk allele in control subjects was 4.63% in the overall population and 3.92% in Asians and 4.36% in Caucasians.

Conclusion

rs798766 is associated with increased risk of bladder cancer, and no ethnic difference was found.

Increased nucleophosmin expression is a strong predictor of recurrence and prognosis in patients with N0M0 upper tract urothelial carcinoma undergoing radical nephroureterectomy

PURPOSE

We aimed to evaluate whether increased nucleophosmin expression predicts recurrence and survival in upper tract urothelial carcinoma (UTUC).

METHODS

Specimens from 101 patients with N0M0 UTUC undergoing radical nephroureterectomy were evaluated. Nucleophosmin expression was determined immunohistochemically and categorized into two groups according to nucleophosmin staining intensity. The association between nucleophosmin expression and various clinicopathological factors including Ki-67 expression was analyzed. Multivariate analyses were performed to identify the independent predictors of extraurothelial recurrence and cancer-specific survival.

RESULTS

High nucleophosmin expression was significantly correlated with tumor location, pT ≥3, lymphovascular invasion, lymph node metastasis, and high Ki-67 expression. Patients whose tumors demonstrated high nucleophosmin expression had a significantly higher rate of extraurothelial recurrence and a lower survival rate than those with low nucleophosmin expression. Multivariate analysis showed that pT ≥3, lymph node metastasis, high nucleophosmin expression, and high Ki-67 expression were independent predictors of extraurothelial recurrence. When patients were stratified into three groups according to the number of risk factors, the 2-year extraurothelial recurrence-free survival rates were 92.9% in patients with 0 or 1 risk factor, 76.5% in patients with 2 risk factors, and 9.1% in patients with 3 or 4 risk factors. Regarding cancer-specific survival, lymphovascular invasion and high nucleophosmin expression were independent predictors.

CONCLUSIONS

Increased nucleophosmin expression was a strong predictor of extraurothelial recurrence and cancer-specific survival in patients with N0M0 UTUC undergoing radical nephroureterectomy. Our risk stratification models integrating nucleophosmin expression may provide valuable information on disease recurrence and prognosis.

Implication of NPM1 phosphorylation and preclinical evaluation of the nucleoprotein antagonist N6L in prostate cancer

Despite the advent of several new treatment options over the past years, advanced/metastatic prostate carcinoma (PCa) still remains incurable, which justifies the search for novel targets and therapeutic molecules. Nucleophosmin (NPM1) is a shuttling nucleoprotein involved in tumor growth and its targeting could be a potential approach for cancer therapy. We previously demonstrated that the multivalent pseudopeptide N6L binds to NPM1 potently affecting in vitro and in vivo tumor cell growth of various tumor types as well as angiogenesis. Furthermore, NPM1 binds to androgen receptor (AR) and modulate its activity. In this study, we first investigated the implication of the NPM1 and its Thr199 and Thr234/237 phosphorylated forms in PCa. We showed that phosphorylated forms of NPM1 interact with androgen receptor (AR) in nucleoplasm. N6L treatment of prostate tumor cells led to inhibition of NPM1 phosphorylation in conjunction with inhibition of AR activity. We also found that total and phosphorylated NPM1 were overexpressed in castration-resistant PCa. Assessment of the potential therapeutic role of N6L in PCa indicated that N6L inhibited tumor growth both in vitro and in vivo when used either alone or in combination with the standard-of-care first- (hormonotherapy) and second-line (docetaxel) treatments for advanced PCa. Our findings reveal the role of Thr199 and Thr234/237 phosphorylated NPM1 in PCa progression and define N6L as a new drug candidate for PCa therapy.

Phosphorylation of signal transducer and activator of transcription 1 reduces bortezomib-mediated apoptosis in cancer cells

The potent and selective proteasome inhibitor bortezomib has shown remarkable antitumor activity and is now entering clinical trials for several cancers. However, the molecular mechanisms by which bortezomib induces cytotoxicity in ovarian cancer cells still remain unclear. In this study, we show that bortezomib induced apoptosis, which was demonstrated by the downregulation of antiapoptotic molecules (Bcl-2, Bcl-XL, p-Bad, and p-AKT) and the upregulation of proapoptotic proteins (p21, p27, and cleaved-Bid) in ovarian cancer cell lines. Moreover, bortezomib stimulates Janus kinase (JAK) phosphorylation and activates heat-shock transcription factor-1 (HSF-1) and heat-shock protein 70 (HSP70), ultimately leading to signal transducer and activator of transcription 1 (STAT1) phosphorylation. Phosphorylated STAT1 partially counteracted apoptosis induced by bortezomib in cancer cells. These findings suggest that the antitumor activity of bortezomib in ovarian cancer can be improved by inhibiting bortezomib-induced STAT1 phosphorylation. This effect can be achieved by STAT1 knockdown, HSP70 knockdown, JAK inhibition, or the addition of cisplatin, one of the most commonly used anticancer drugs. These results provide the first evidence that STAT1 phosphorylation can play a role in bortezomib resistance by exerting antiapoptotic effects. They also suggest the possibility to abolish or reduce bortezomib chemoresistance in ovarian cancer by the addition of cisplatin or JAK inhibitors.

Estrogen stimulates the proliferation of human endometrial cancer cells by stabilizing nucleophosmin/B23 (NPM/B23)

Unopposed estrogen exposure is an important factor in the tumorigenesis of endometrial cancer. Nucleophosmin/B23 (NPM/B23), a phosphoprotein that has pleiotropic functions in cells, plays an important role in various cancers. However, the regulatory role of NPM/B23 in estrogen signaling in endometrial cancer has not been explored. Here, we report that NPM/B23 was required for estrogen-induced endometrial proliferation, and the increase in NPM/B23 was estrogen receptor α-dependent. Furthermore, estrogen increased NPM/B23 protein levels by repressing its ubiquitination and subsequently stabilizing the protein. The overexpression of the alternate reading frame (ARF) suppressed the estrogen-induced increase in the NPM/B23 protein levels, indicating that ARF inhibited the observed estrogen-mediated NPM/B23 stabilization. Our results suggest that one of the effects of estrogen on endometrial proliferation is the suppression of the NPM/B23-ARF interaction and the subsequent increase in NPM/B23 protein levels. This novel characterization of NPM/B23 in estrogen-mediated cell proliferation may extend our understanding of the tumorigenesis of steroid hormone-related cancers.

Expression of nucleophosmin/NPM1 correlates with migration and invasiveness of colon cancer cells

Background

We aimed to examine the expression level of Nucleophosmin (NPM1) protein in colon cancer tissues and to investigate the potential role of NPM1 in the regulation of cell migration and invasiveness.

Methods

Immunohistochemical assay was performed to examine the expression pattern of NPM1 in 31 groups of colonic carcinoma samples, including colon tumors, adjacent normal tissues, and matched metastatic lymph nodes from the same patients. Small interfering RNA technique and exogenous expression of wild type NPM1 methods were used to further verify the function of NPM1.

Results

High-expression of NPM1 correlates with lymph node metastasis (P = 0.0003) and poor survival rate of human colon cancer patients (P = 0.017). SiRNA-mediated reduction of NPM1 was also shown to inhibit the migration and invasiveness of metastatic colon cancer HCT116 cell line. In addition, the exogenous expression of NPM1 in HT29 cells, a NPM1 low expression and low invasive colon cancer cell line, enhanced cell migration and invasiveness along with increased cell proliferation.

Conclusions

The current study uncovered the critical role of NPM1 in the regulation of colon cancer cells migration and invasion, and NPM1 may serve as a potential marker for the prognosis of colon cancer patients.

The Multifunctional Nucleolar Protein Nucleophosmin/NPM/B23 and the Nucleoplasmin Family of Proteins

The nucleophosmin (NPM)/nucleoplasmin family of nuclear chaperones has three members: NPM1, NPM2, and NPM3. Nuclear chaperones serve to ensure proper assembly of nucleosomes and proper formation of higher order structures of chromatin. In fact, this family of proteins has such diverse functions in cellular processes such as chromatin remodeling, ribosome biogenesis, genome stability, centrosome replication, cell cycle, transcriptional regulation, apoptosis, and tumor suppression. Of the members of this family, NPM1 is the most studied and is the main focus of this review. NPM2 and NPM3 are less well characterized, and are also discussed wherever appropriate. The structure–function relationship of NPM proteins has largely been worked out. Other than the many processes in which NPM1 takes part, the major interest comes from its involvement in human cancers, particularly acute myeloid leukemia (AML). Its significance stems from the fact that AML with mutated NPM1 accounts for ∼30% of all AML cases and usually has good prognosis. Its clinical importance also comes from its involvement in virus replication, particularly in the era of outbreaks of infectious diseases.

Nanotopographical control of stem cell differentiation

Stem cells have the capacity to differentiate into various lineages, and the ability to reliably direct stem cell fate determination would have tremendous potential for basic research and clinical therapy. Nanotopography provides a useful tool for guiding differentiation, as the features are more durable than surface chemistry and can be modified in size and shape to suit the desired application. In this paper, nanotopography is examined as a means to guide differentiation, and its application is described in the context of different subsets of stem cells, with a particular focus on skeletal (mesenchymal) stem cells. To address the mechanistic basis underlying the topographical effects on stem cells, the likely contributions of indirect (biochemical signal-mediated) and direct (force-mediated) mechanotransduction are discussed. Data from proteomic research is also outlined in relation to topography-mediated fate determination, as this approach provides insight into the global molecular changes at the level of the functional effectors.