NPM2 in malignant peritoneal mesothelioma: from basic tumor biology to clinical medicine

Organoids derived from patients provide a new opportunity for research and individualized treatment of malignant peritoneal mesothelioma

BACKGROUND

Malignant peritoneal mesothelioma (MPM) is an extremely rare and highly invasive tumor. Due to the lack of accurate models that reflect the biological characteristics of primary tumors, studying MPM remains challenging and is associated with an exceedingly unfavorable prognosis. This study was aimed to establish a new potential preclinical model for MPM using patient-derived MPM organoids (MPMOs) and to comprehensively evaluate the practicality of this model in medical research and its feasibility in guiding individualized patient treatment.

METHODS

MPMOs were constructed using tumor tissue from MPM patients. Histopathological analysis and whole genome sequencing (WGS) were employed to determine the ability of MPMOs to replicate the original tumor's genetic and histological characteristics. The subcutaneous and orthotopic xenograft models were employed to assess the feasibility of establishing an in vivo model of MPM. MPMOs were also used to conduct drug screening and compare the results with retrospective analysis of patients after treatment, in order to evaluate the potential of MPMOs in predicting the effectiveness of drugs in MPM patients.

RESULTS

We successfully established a culture method for human MPM organoids using tumor tissue from MPM patients and provided a comprehensive description of the necessary medium components for MPMOs. Pathological examination and WGS revealed that MPMOs accurately represented the histological characteristics and genomic heterogeneity of the original tumors. In terms of application, the success rate of creating subcutaneous and orthotopic xenograft models using MPMOs was 88% and 100% respectively. Drug sensitivity assays demonstrated that MPMOs have different medication responses, and these differences were compatible with the real situation of the patients.

CONCLUSION

This study presents a method for generating human MPM organoids, which can serve as a valuable research tool and contribute to the advancement of MPM research. Additionally, these organoids can be utilized as a means to evaluate the effectiveness of drug treatments for MPM patients, offering a model for personalized treatment approaches.

Hexavalent chromium causes centrosome amplification by inhibiting the binding between TMOD2 and NPM2

BACKGROUND

Hexavalent chromium can promote centrosome amplification (CA) as well as tumorigenesis. Since CA can lead to tumorigenesis, it is plausible that the chromium promotes the development of cancer via CA. In the present study, we investigated the signaling pathways of the chromium-induced CA.

RESULTS

Our results showed that sub-toxic concentration of chromium was able to cause CA in HCT116 cells, and decrease the expression of TMOD2 and NPM2. Furthermore, TMOD2 and NPM2 interacted to each other via their C-terminal and the N-terminal, respectively, which was inhibited by the chromium. Overexpression of TMOD2 and NPM2 increased their binding and significantly attenuated the CA. Moreover, TMOD2 and NPM2 were co-localized with the centrosomes. The chromium inhibited the centrosomeal localization of NPM2, which was reversed by the overexpression of TMOD2, C-terminal of TMOD2, but not the N-terminal of NPM2.

CONCLUSION

Our results suggest that the chromium induces CA via inhibiting the binding between TMOD2 and NPM2 as well as the dissociation of NPM2 from centrosomes.

AVAILABILITY OF DATA AND MATERIALS

The data and materials are available from the corresponding authors.

Loss of NPM2 expression is a potential immunohistochemical marker for malignant peritoneal mesothelioma: a single-center study of 92 cases

Background

Malignant peritoneal mesothelioma (MPM) is a rare malignant tumor with a high mortality rate and extremely poor prognosis. In-depth pathological analysis is essential to assess tumor biological behaviors and explore potential therapeutic targets of MPM. Nucleoplasmin 2 (NPM2) is a molecular chaperone that binds histones and may play a key role in the development and progression of tumors. This study aimed to analyze the correlation between the expression level of NPM2 and the main clinicopathological characteristics and prognosis of MPM.

Methods

Ninety-two postoperative specimens from MPM patients following cytoreductive surgery were collected. Postoperative specimens were stained with immunohistochemistry. The expression level of NPM2 was quantitatively analyzed by QuPath-0.3.2 software. Univariate and multivariate analyses were conducted to investigate the correlation between NPM2 expression and other conventional clinicopathological characteristics.

Results

Among the 92 MPM patients, there were 47 males (48.9%) and 45 females (51.1%), with a median age of 56 (range: 24–73). There were 70 (76.0%) cases with loss of NPM2 protein expression, 11 (12.0%) cases with low expression, and 11 (12.0%) cases with high expression. Univariate analysis showed that NPM2 protein expression level (negative vs. low expression vs. high expression) was negatively correlated with the following three clinicopathological factors: completeness of cytoreduction (CC) score, vascular tumor emboli, and serious adverse events (SAEs) (all P < 0.05). Multivariate analysis showed that NPM2 protein expression level (negative vs. low expression vs. high expression) was independently negatively correlated with the following two clinicopathological factors: CC score [odds ratio (OR) = 0.317, 95% CI: 0.317–0.959, P = 0.042] and vascular tumor emboli (OR = 0.092, 95% CI = 0.011–0.770, P = 0.028). Survival analysis showed that loss of NPM2 protein expression (negative vs. positive) was associated with poor prognosis of MPM.

Conclusions

Loss of NPM2 expression is a potential immunohistochemical marker for MPM.

Prognostic factors of malignant peritoneal mesothelioma: a retrospective study of 52 female patients

BACKGROUND

Prognosis in malignant peritoneal mesothelioma (MPM) remains poor, and the associated factors are unclear. Therefore, this study aimed to investigate the prognostic factors of MPM.

METHODS

A total of 52 female MPM patients treated in 2012-2017 were retrospectively analyzed. Kaplan-Meier survival curves were generated for survival analysis by the log-rank test. The Cox regression model was used for univariate and multivariate analyses.

RESULTS

Univariate analysis showed that median survival time (MST) was longer in the epithelioid type compared with the sarcomatoid type (12 months vs 5 months); cumulative survival rates at 12 months were 45.7% and 0%, respectively (P=0.005). MST was longer in patients with proliferating cell nuclear antigen (Ki67) ≤ 10% compared with those with Ki67 > 10% (15 months vs 11 months). Cumulative survival rates at 12 months were 60.0% and 28.1%, respectively (P=0.036). MSTs in patients administered peritoneal biopsy or adnexectomy + paclitaxel + platinum perfusion, peritoneal biopsy (or adnexectomy) + pemetrexed + platinum perfusion, cytoreductive surgery + paclitaxel + platinum perfusion, and cytoreductive surgery + pemetrexed + platinum perfusion were 6, 11, 12, and 24 months, respectively, with cumulative survival rates at 12 months of 0%, 35.7%, 45.5%, and 73.3%, respectively. Survival time after cytoreductive surgery combined with pemetrexed + platinum was the longest. In multivariate analysis, pathological type, T staging, and therapeutic regimen were independent prognostic factors of MPM (P < 0.05).

CONCLUSIONS

Prognosis in MPM is associated with pathological subtype, clinical staging, cytoreductive surgery, and subsequent pemetrexed use. Radical cytoreductive surgery and postoperative use of pemetrexed prolong survival.