Management of soft tissue sarcomas of the extremities

Human mesenchymal stromal cells do not promote recurrence of soft tissue sarcomas in mouse xenografts after radiation and surgery

BACKGROUND

Mesenchymal stromal cells (MSCs) promote wound healing, including after radiotherapy (RT) and surgery. The use of MSCs in regenerative medicine in the context of malignancy, such as to enhance wound healing post-RT/surgery in patients with soft tissue sarcomas (STSs), requires safety validation. The aim of this study was to determine the effects of human MSCs on STS growth in vitro and local recurrence and metastasis in vivo.

METHODS

Human primary STS and HT-1080 fibrosarcoma lines were transduced to express luciferase/eGFP (enhanced green fluorescent protein). Sarcoma cells were co-cultured or co-injected with bone marrow-derived MSCs for growth studies. Xenograft tumor models were established with STS lines in NOD/SCID/γ_c^null mice. To emulate a clinical scenario, subcutaneous tumors were treated with RT/surgery prior to MSC injection into the tumor bed. Local and distant tumor recurrence was studied using histology and bioluminescence imaging.

RESULTS

MSCs did not promote STS proliferation upon co-culture in vitro, which was consistent among MSCs from different donors. Co-injection of MSCs with sarcoma cells in mice exhibited no significant tumor-stimulating effect, compared with control mice injected with sarcoma cells alone. MSC administration after RT/surgery had no effect on local recurrence or metastasis of STS.

DISCUSSION

These studies are important for the establishment of a safety profile for MSC administration in patients with STS. Our data suggest that MSCs are safe in STS management after standard of care RT/surgery, which can be further investigated in early-phase clinical trials to also determine the efficacy of MSCs in reducing morbidity and to mitigate wound complications in these patients.

Therapeutic potential of irreversible electroporation in sarcoma

Irreversible electroporation is a newly developed nonthermal tissue ablation technique in which certain short-duration electrical fields are used to permanently permeabilize the cell membrane to disrupt cellular homeostasis. This disruption of cellular homeostasis initiates apoptosis, which leads to permanent cell death. Sarcomas are generally divided into soft-tissue and bone sarcomas based on their different mesenchymal origins and anatomical locations. Each of these sarcomas present in different ways, exhibit different behaviors and prognoses, and present unique therapeutic challenges. In this article, a series of recently conducted irreversible electroporation treatment for sarcomas based on local nonthermal ablation are summarized, and the therapeutic potential of this newly developed technique is assessed.

The Vascularised Groin Chamber: A Novel Model for Growing Primary Human Liposarcoma in Nude Mice

Background

The preclinical development of anti-sarcoma drugs has been primarily based on the subcutaneous transplantation of xenografts. Transplant survival remains an obstacle of current models which has been attributed to the period of hypoxia after transplantation. We hypothesized that primary soft tissue sarcoma models with an intrinsic tissue engineered vascular supply would be easily reproducible. The aim of this study was to establish a model of primary human soft tissue sarcoma with an intrinsic vascular supply.

Methods

Primary soft tissue sarcoma cells from resected human liposarcomas isolated and divided into tumour fragments were transplanted into a silicon chamber, placed around the superficial epigastric vessels in mice. Sarcoma xenograft samples were analysed histomorphologically (light/electron microscopy and immunohistochemistry).

Results

All primary soft tissue sarcoma transplants engrafted, leading to solid tumours within 3 weeks. Histological and immunohistochemical staining confirmed the mouse xenografts as identical high grade liposarcomas compared to original tumour tissue.

Conclusion

This study established a reproducible xenograft model of primary human liposarcoma. This animal model could be of high value for studying human soft tissue sarcomas and their therapy.

A novel xenograft model with intrinsic vascularisation for growing undifferentiated pleomorphic sarcoma NOS in mice

PURPOSE

Preclinical development of antisarcoma therapy is primarily based on the subcutaneous transplantation of sarcoma xenografts. Tumour cell survival remains a hurdle of current models, which has been attributed to the hypoxic conditions following transplantation. We hypothesised that sarcoma models with an intrinsic tissue-engineered vascular supply are easily reproducible. The aim of this study was to establish a novel vascularised xenograft model.

MATERIALS AND METHODS

Primary human soft tissue sarcomas were transplanted into a silicon chamber and placed around the superficial epigastric vessels of nude mice. Sarcoma xenograft samples were assessed histomorphologically.

RESULTS

All sarcoma xenografts engrafted, leading to solid tumours. Histological, immunohistochemical staining and light/electron microscopy confirmed the xenografts as identical high-grade pleomorphic sarcomas (NOS) compared with the original patients' tumours.

CONCLUSION

This novel sarcoma xenograft model with an intrinsic vascular supply could be of high value for studying human soft tissue sarcomas and their therapy.

Up-regulation of the DR5 expression by proteasome inhibitor MG132 augments TRAIL-induced apoptosis in soft tissue sarcoma cell lines

Purpose

Current chemotherapeutics for treating locally advanced or metastatic soft tissue sarcomas (STS) are limited. Accordingly, the present in vitro study was conducted to evaluate the effects of treatment of STS cells with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) applied as a single agent or in combination with a proteasome inhibitor, MG132.

Materials and Methods

Sensitivity to TRAIL and activity of TRAIL-induced apoptotic pathways were analyzed in four STS cell lines: HTB-82 (rhabdomyosarcoma), HT-1080 (fibrosarcoma), HTB-93 (synovial sarcoma), and HTB-94 (chondrosarcoma). Reduction of the dye dimethylthiazolyl 2,5 diphenyltetrazolium bromide (MTT) was used to evaluate cytotoxic activity; western blots were used to evaluate TRAIL-induced apoptosis.

Results

TRAIL induced apoptosis in HTB-93 cells, but had little effect in HTB-82, HT-1080, or HTB-94 cells. Expression of TRAIL receptor-1 and -2 did not correlate with sensitivity to TRAIL. Co-incubation of cells with TRAIL and a proteasome inhibitor, MG132, augmented the apoptotic effect of TRAIL in both TRAIL-sensitive and TRAIL-resistant cells. This effect was due to up-regulation of TRAIL receptors and members of the pro-apoptotic BCL-2 family by MG132.

Conclusion

These data show that combining TRAIL with MG132 enhances apoptosis and overcomes TRAIL resistance. This restoration of TRAIL sensitivity occurs through an increase in the expression of death receptor 5 and of pro-apoptotic BCL-2 family members such as BAX.

Developments in the Management of Extremity Soft Tissue Sarcomas

Soft tissue sarcomas, a rare and extremely low prevalence tumor, has no uniform treatment recommendation because there have been few randomized prospective trials to guide management. Recently, there have been surgical, medical, biologic, and genetic advances toward improved treatment. A multidisciplinary approach at specialized treatment centers should be sought because the skill set necessary to implement these advances can be provided and outcomes improved. Centralized care will be crucial to improving survival and functional outcome because it will allow for patients to be effectively entered into prospective randomized trials and create regional and national tissue banks to generate meaningful data.

The value of expert second opinion in diagnosis of soft tissue sarcomas

INTRODUCTION

Soft tissue sarcomas represent a heterogeneous group of tumours with a wide range of clinical behaviour. Exact determination of diagnosis and prognosis is critical in order to guide surgical decisions and provide systemic therapy or radiation for patients. The value of consultative second opinions has been proven for general surgical pathology; some studies suggest an even higher value for the soft tissue tumour specimens in particular.

METHODS

We reviewed 603 patients who were operated on at our institution with the diagnosis of soft tissue sarcoma and aggressive fibromatosis; we focused on mismatches in primary and definite tumour-entity and -grading with respect to the diagnosing institution and the primary surgical procedure.

RESULTS

We found concordant primary diagnosis in 28.3% for pathologists in private clinics, 29.6% for hospital pathologists, 36.8% for academic medical centres (university hospitals) and 70.5% for the Department of Pathology at our institution. An improvement in diagnosis or confirmation of the correct primary diagnosis by the second opinion was seen in 73.1% of the patients; in 2.5%, the second opinion was false.

DISCUSSION

For accurate determination of prognosis and to provide optimal therapeutic decisions we consider expert second opinion essential for optimal treatment of soft tissue sarcomas.

Locally advanced and metastatic sarcoma (adult type) including gastrointestinal stromal tumors

STS belong to the most challenging diseases in oncology that demand all resources of modern clinical oncology. With the improvement of surgical techniques and radiation therapy the majority of patients with localized disease can be cured. However, for patients with locally advanced or metastatic disease chemotherapeutic treatments have not greatly changed the poor outcome of the disease. The introduction of combined chemoradiotherapy as well as isolated limb-perfusion has improved the limb-salvage rate in locally advanced disease but the impact of systemic chemotherapy on overall survival remains a subject of dispute. For patients with metastatic sarcoma long-term survival can only be achieved in a small number of patients with mostly resectable disease. The list of effective drugs for palliative treatment in general still remains short and the duration of remissions usually does not exceed several months. The lack of alternative chemotherapeutic drugs imposes a considerable challenge in daily clinical practice with many young patients exhibiting a good performance status but progressive disease after standard treatment. A variety of new drugs or drug combinations seem to exhibit considerable activity in certain histological sarcoma subtypes, which may soon broaden the armamentarium of drugs for a subset of patients. However, with the vastly improved understanding of the biology and pathology of soft tissue sarcoma an era of opportunities seems to have begun and the recent success in the treatment of gastrointestinal stromal tumors impressively shows how fast a gain in the understanding of oncogenic mechanisms may translate into a highly efficient, clinically useful treatment.