Expression of drug resistance related proteins in sarcomas of the pulmonary artery and poorly differentiated leiomyosarcomas of other origin

Analysis of Multiple Drug Resistance Mechanism in Different Types of Soft Tissue Sarcomas: Assessment of the Expression of ABC-Transporters, MVP, YB-1, and Analysis of Their Correlation with Chemosensitivity of Cancer Cells

Chemotherapy of soft tissue sarcomas (STS) is restricted by low chemosensitivity and multiple drug resistance (MDR). The purpose of our study was the analysis of MDR mechanism in different types of STS. We assessed the expression of ABC-transporters, MVP, YB-1, and analyzed their correlation with chemosensitivity of cancer cells. STS specimens were obtained from 70 patients without metastatic disease (2018–2020). Expression level of MDR-associated genes was estimated by qRT-PCR and cytofluorimetry. Mutations in ABC-transporter genes were captured by exome sequencing. Chemosensitivity (SI) of STS to doxorubicin (Dox), ifosfamide (Ifo), gemcitabine (Gem), and docetaxel (Doc) was analyzed in vitro. We found strong correlation in ABCB1, ABCC1, and ABCG2 expression. We demonstrated strong negative correlations in ABCB1 and ABCG2 expression with SI (Doc) and SI (Doc + Gem), and positive correlation of MVP expression with SI (Doc) and SI (Doc + Gem) in undifferentiated pleomorphic sarcoma. Pgp expression was shown in 5 out of 44 STS samples with prevalence of synovial sarcoma relapses and it is strongly correlated with SI (Gem). Mutations in MDR-associated genes were rarely found. Overall, STS demonstrated high heterogeneity in chemosensitivity that makes reasonable in vitro chemosensitivity testing to improve personalized STS therapy, and classic ABC-transporters are not obviously involved in MDR appearance.

Celastrol, a plant-derived triterpene, induces cisplatin-resistance nasopharyngeal carcinoma cancer cell apoptosis though ERK1/2 and p38 MAPK signaling pathway

BACKGROUND

Developing resistance to chemotherapeutic drugs has become a major problem in the management of nasopharyngeal carcinoma (NPC). To overcome this issue, use of natural plant products as chemosensitizers is gaining importance at a fast pace.

HYPOTHESIS/PURPOSE

The present study was designed to evaluate the cytotoxic effect and mode of action of a natural pentacyclic triterpenoid, celastrol, on cisplatin-resistant NPC cells.

RESULTS

Study results revealed that celastrol treatment significantly reduced the viability of NPC cells in dose and time dependent manners, as compared to untreated control cells. The cytotoxic effect of celastrol was mediated by cell cycle arrest at G2/M phase and induction of intrinsic and extrinsic apoptotic pathways. With further analysis, we observed that celastrol-induced activation of caspases was accompanied by increased phosphorylation of MAPK pathway proteins, p38, ERK1/2.

CONCLUSION

Taken together, our observation provides a novel insight on use of a natural plant product, celastrol, in the management of chemoresistant NPC.

Expression of E-cadherin, beta-catenin and topoisomerase IIalpha in leiomyosarcomas

INTRODUCTION

The expression of E-cadherin, beta-catenin and topoisomerase II has been associated with clinical outcome of several cancers including sarcomas. We aimed to evaluate the expression of these markers in leiomyosarcomas (LMS).

MATERIALS AND METHODS

Paraffin blocks of 19 primary, nonmetastatic LMS were analysed immunohistochemically for the expression of the above-mentioned markers with a cutoff level for positivity of 20% of cell staining.

RESULTS

Expression of E-cadherin was negative in all LMS. Nuclear expression of beta-catenin was also negative in all cases, while positive cytoplasmic beta-catenin expression was observed in approximately half of the patients. The majority of LMS had expression of topoisomerase IIalpha, although only in 10 patients was this expression in more than 20% of tumour cells. From the analysed factors, tumour size was statistically significantly correlated with relapse-free survival.

CONCLUSIONS

Further evidence with larger series is required in order to determine the implication of these markers in LMS.

Mechanisms of multidrug resistance in cancer

The development of multidrug resistance (MDR) to chemotherapy remains a major challenge in the treatment of cancer. Resistance exists against every effective anticancer drug and can develop by numerous mechanisms including decreased drug uptake, increased drug efflux, activation of detoxifying systems, activation of DNA repair mechanisms, evasion of drug-induced apoptosis, etc. In the first part of this chapter, we briefly summarize the current knowledge on individual cellular mechanisms responsible for MDR, with a special emphasis on ATP-binding cassette transporters, perhaps the main theme of this textbook. Although extensive work has been done to characterize MDR mechanisms in vitro, the translation of this knowledge to the clinic has not been crowned with success. Therefore, identifying genes and mechanisms critical to the development of MDR in vivo and establishing a reliable method for analyzing clinical samples could help to predict the development of resistance and lead to treatments designed to circumvent it. Our thoughts about translational research needed to achieve significant progress in the understanding of this complex phenomenon are therefore discussed in a third section. The pleotropic response of cancer cells to chemotherapy is summarized in a concluding diagram.

Synergistic antitumor activity of ixabepilone (BMS-247550) plus bevacizumab in multiple in vivo tumor models

PURPOSE

Angiogenesis is a critical step in the establishment, growth, and metastasis of solid tumors, and combination of antiangiogenic agents with chemotherapy is an attractive therapeutic option. We investigated the potential of ixabepilone, the first in a new class of antineoplastic agents known as epothilones, to synergize with antiangiogenic agents to inhibit tumor growth.

EXPERIMENTAL DESIGN

In vitro and in vivo cytotoxicity of ixabepilone as single agent and in combination with two targeted antiangiogenic agents, bevacizumab or sunitinib, were examined in preclinical tumor models. Direct effects of the agents against endothelial cells was also examined and compared with the effects of paclitaxel as single agent and in combination with bevacizumab.

RESULTS

Ixabepilone showed robust synergistic antitumor activity in combination with bevacizumab and sunitinib in preclinical in vivo models derived from breast, colon, lung, and kidney cancers. The synergistic antitumor effect was greater with ixabepilone compared with paclitaxel. Furthermore, ixabepilone was more effective than paclitaxel at killing endothelial cells expressing P-glycoprotein in vitro and inhibiting endothelial cell proliferation and tumor angiogenesis in vivo.

CONCLUSIONS

Ixabepilone may enhance the antitumor effects of antiangiogenic therapy by direct cytotoxicity and also indirectly via the killing of tumor-associated endothelial cells. Given that ixabepilone has reduced susceptibility to drug efflux pumps compared with taxanes, these data may explain the increased antiangiogenic and antitumor activity of ixabepilone in combination with antiangiogenic agents. Phase II studies to assess the efficacy and safety of ixabepilone plus bevacizumab in locally recurrent or metastatic breast cancer are planned.

Chemoresistance induces enhanced adhesion and transendothelial penetration of neuroblastoma cells by down-regulating NCAM surface expression

Background

Drug resistance to chemotherapy is often associated with increased malignancy in neuroblastoma (NB). One explanation for the link between resistance and malignancy might be that resistance facilitates cancer progression and invasion. To investigate this hypothesis, adhesion, transendothelial penetration and NCAM (CD56) adhesion receptor expression of drug-resistant versus drug-sensitive NB tumor cells were evaluated.

Methods

Acquired drug resistance was mimicked by exposing parental UKF-NB-2, UKF-NB-3 or IMR-32 tumor cells to increasing concentrations of vincristine- (VCR) or doxorubicin (DOX) to establish the resistant tumor cell sublines UKF-NB-2^VCR, UKF-NB-2^DOX, UKF-NB-3^VCR, UKF-NB-3^DOX, IMR-32^VCR and IMR-32^DOX. Additionally, the malignant behaviour of UKF-NB-4, which already possessed the intrinsic multidrug resistance (MDR) phenotype, was analyzed. UKF-NB-4 exposed to VCR or DOX were designated UKF-NB-4^VCR or UKF-NB-4^DOX. Combined phase contrast – reflection interference contrast microscopy was used to separately evaluate NB cell adhesion and penetration. NCAM was analyzed by flow cytometry, western blot and RT-PCR.

Results

VCR and DOX resistant tumor sublines showed enhanced adhesion and penetration capacity, compared to their drug naïve controls. Strongest effects were seen with UKF-NB-2^VCR, UKF-NB-3^VCR and IMR-32^DOX. DOX or VCR treatment also evoked increased invasive behaviour of UKF-NB-4. The process of accelerated tumor invasion was accompanied by decreased NCAM surface and protein expression, and down-regulation of NCAM coding mRNA. Transfection of UKF-NB-4^VCR cells with NCAM cDNA led to a significant receptor up-regulation, paralleled by diminished adhesion to an endothelial cell monolayer.

Conclusion

It is concluded that NB cells resistant to anticancer drugs acquire increased invasive capacity relative to non-resistant parental cells, and that enhanced invasion is caused by strong down-regulation of NCAM adhesion receptors.

Immunoexpression of multidrug-resistance protein 2 and cyclooxygenase 2 in medullary thyroid carcinomas

CONTEXT

Chemoresistance is due to the expression of multidrug-resistance proteins (MRPs). Cyclooxygenase 2 (COX2), a key enzyme in prostaglandins synthesis, upregulates MRP1. MRP1 is overexpressed in medullary thyroid carcinomas (MTCs), but it is not involved in resistance to doxorubicin and cisplatin, which are commonly used in MTC treatment. MRP2 is specifically involved in resistance to both chemotherapeutic agents, but no data exist on the expression of MRP2 and COX2 in MTC.

OBJECTIVE

To evaluate MRP2 and COX2 expressions in MTC.

DESIGN

We analyzed immunohistochemical expression of MRP2 and COX2 in 12 MTCs and in 6 lymph node metastases. Results were correlated with pTNM and clinical stage.

RESULTS

MRP2 and COX2 expressions were observed only in tumor samples and metastases. Nine MTCs, all pTNM stage T4, were positive for MRP2, whereas 3 MTCs, pTNM stages T2 and T3, were unreactive for MRP2. Six metastatic MTCs at stage T4 showed higher proportion of MRP2+ cells, compared with primary tumors. All 12 MTCs were positive for COX2. Three MTCs, pTNM stage T2 and T3, showed COX2 positivity in all cells. The proportion of COX2+ cells decreased with increased pTNM stage. Four out of 6 metastatic MTCs, stage T4, showed a lower proportion of COX2+ cells, compared with primary tumors. The proportion of MRP2+ cells was inversely related to the proportion of COX2+ cells.

CONCLUSIONS

MRP2 and COX2 expression correlated with pTNM stage. High MRP2 and low COX2 expression may explain resistance to doxorubicin and cisplatin, which is observed in advanced stage MTC. Evaluation of the expression pattern of these 2 proteins may be useful to predict chemosensitivity of these types of tumors.

Apoptotic and cell cycle regulatory markers in uterine leiomyosarcoma

OBJECTIVES

The primary aim of this study was to investigate the expression of apoptotic and cell cycle regulators p53, p21, p27, bax, and bcl-2 in uterine leiomyosarcoma in order to identify molecular pathways that possibly could be important in the development of leiomyosarcoma. A secondary aim was to examine if the apoptotic and cell cycle regulatory protein expression profile of uterine leiomyosarcoma is potentially useful for clinical prognostic purposes.

METHODS

A tissue microarray representing 36 uterine leiomyosarcomas and 19 uterine leiomyomas was created with 3 representative cores from each tumor. Immunohistochemical staining was performed for bcl-2, bax, p21, p27, and p53 using standard techniques. Staining was scored 0-12 for each marker, 0-3 being negative and 4-12 positive. Outcome analyses were performed only for leiomyosarcomas. First recurrence was determined from the time of initial diagnosis. Survival was determined from the time of initial diagnosis to last follow-up.

RESULTS

Associations were found between disease type (leiomyosarcoma vs. leiomyoma) and the positivity status of p21 (43% vs. 0%, P < 0.001), p53 (54% vs. 0%, P < 0.001), and bax (34% vs. 94%, P < 0.001). bcl-2-positive leiomyosarcoma was associated with a longer time to recurrence (P = 0.02) in a univariate analysis. In a multivariate analysis, tumor stage was the only independent significant prognostic factor (P = 0.002).

CONCLUSION

The significant differential expression of apoptotic and cell cycle regulatory proteins in uterine leiomyosarcoma as compared to benign smooth muscle tumors suggests that pathways involving these proteins may be important in the development of malignant disease and, therefore, could be potential targets for molecular therapies.

Intimal sarcoma of the pulmonary artery: Report of an autopsy case

Primary pulmonary artery sarcomas (PASs) are rare and lethal tumors. They are easily misdiagnosed as chronic pulmonary embolism, mediastinal mass or tumor emboli, which delay a proper treatment. Although the advanced technologies are now increasingly being used, their diagnosis is usually hard to establish preoperatively at the present time. We report here a case of a 68-year-old female with PAS with lung metastases, who firstly presented with symptoms of common cold and anemia. Although a PAS had been suspected, the final diagnosis of pulmonary intimal sarcoma was made only postoperatively by histological and immunohistochemical examination. The patient died 8 months after the operation because of tumor growth progression, despite adjuvant chemotherapy and radiation therapy. Although pulmonary intimal sarcomas are usually of poorly differentiated mesenchymal malignancy, most reported cases are immunohistochemically positive for vimentin, alpha-smooth muscle actin (SMA), and/or desmin, therefore resembling leiomyosarcomas. However, the diagnosis of leiomyosarcoma should not be made on the basis of immunostains in the absence of typical morphologic features, and PAS, like the present case, should be more appropriately classified as intimal sarcoma according to the new WHO Classification of Tumours of Soft Tissue and Bone published in 2002.

Metallothionein expression in human neoplasia

The metallothionein family is a class of low-molecular-weight, cysteine-rich proteins with high affinity for metal ions. Four major isoforms (metallothionein-1, -2, -3, and -4) have been identified in mammals, involved in many pathophysiological processes, including metal ion homeostasis and detoxification, protection against oxidative damage, cell proliferation and apoptosis, drug and radiotherapy resistance and several aspects of the carcinogenic process. In the present review we examine the expression of metallothionein in different human tumours and its correlation with histopathological variables, tumour cell proliferation or apoptosis, resistance to radiation or chemotherapy, patient survival and prognosis. A variable profile of metallothionein and its isoforms' expression has been observed in different cancer types. Although metallothionein expression has been implicated in carcinogenic evolution, its use as a marker of tumour differentiation, cell proliferation and prognosis predictor remains unclear. Detailed studies focused on the expression of metallothionein isoforms and isotypes in different tumour types could elucidate the role of this group of proteins in the carcinogenic process, delineating its possible clinical significance for the management of patients.