Disruption of myoblast alignment by highly motile rhabdomyosarcoma cell in tissue structure

Rhabdomyosarcoma: Current Therapy, Challenges, and Future Approaches to Treatment Strategies

Rhabdomyosarcoma is a rare cancer arising in skeletal muscle that typically impacts children and young adults. It is a worldwide challenge in child health as treatment outcomes for metastatic and recurrent disease still pose a major concern for both basic and clinical scientists. The treatment strategies for rhabdomyosarcoma include multi-agent chemotherapies after surgical resection with or without ionization radiotherapy. In this comprehensive review, we first provide a detailed clinical understanding of rhabdomyosarcoma including its classification and subtypes, diagnosis, and treatment strategies. Later, we focus on chemotherapy strategies for this childhood sarcoma and discuss the impact of three mechanisms that are involved in the chemotherapy response including apoptosis, macro-autophagy, and the unfolded protein response. Finally, we discuss in vivo mouse and zebrafish models and in vitro three-dimensional bioengineering models of rhabdomyosarcoma to screen future therapeutic approaches and promote muscle regeneration.

Natural Tissue-Imprinted Biointerface for the Topographical Education of a Biomimetic Cell Sheet

Cell sheet engineering as a cell-based scaffold-free therapy is promising in tissue engineering, allowing precise transforming treatments for various tissue damage. However, the current cutting-edge techniques are still hampered by the difficulty in mimicking the natural tissue organizations and the corresponding physiological functions. In this work, cell-imprinting technology using the natural tissue as a template was proposed to rationally educate the cellular alignment in the cell sheet. Through this technique, we obtained temporary templates with morphological structure complementary to native tissues and then directly transferred the structure on the template to the collagen layer on a photothermally convertible substrate by secondary imprinting replication. The resultant biomimetic interface was used for cell culture and release to obtain a cell sheet with a texture similar to the natural tissue morphology. Different from conventional photolithography, the natural tissue-imprinted biointerface guides the geometry of cell sheets in the way of natural principles instead of stereotyped or overuniform cell organization. Simultaneously, a near-infrared laser (NIR) was used to irradiate the photothermally responsive substrate to obtain complete cell sheets efficiently and nondestructively. The natural tissue-educated myocardium cell sheets exhibited good physiological activity and biomimetic biofunctions, such as mechanical properties and physiological performances. This approach might open an inspiring prospect in regenerative medicine and offer a new approach to realizing the biomimetic tissue construction.

A bioengineering method for modeling alveolar Rhabdomyosarcoma and assessing chemotherapy responses

Rhabdomyosarcoma (RMS) is the most common pediatric soft-tissue malignant tumor. Treatment of RMS usually includes primary tumor resection along with systemic chemotherapy. Two-dimensional (2D) cell culture systems and animal models have been extensively used for investigating the potential efficacy of new RMS treatments. However, RMS cells behave differently in 2D culture than in vivo, which has recently inspired the adoption of three-dimensional (3D) culture environments. In the current paper, we will describe the detailed methodology we have developed for fabricating a 3D engineered model to study alveolar RMS (ARMS) in vitro. This model consists of a thermally cross-linked collagen disk laden with RMS cells that mimics the structural and bio-chemical aspects of the tumor extracellular matrix (ECM). This process is highly reproducible and produces a 3D engineered model that can be used to analyze the cytotoxicity and autophagy induction of drugs on ARMS cells. The most improtant bullet points are as following:•

We fabricated 3D model of ARMS.

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The current ARMS 3D model can be used for screening of chemotherapy drugs.

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We developed methods to detect apoptosis and autophagy in ARMS 3D model to detect the mechansims of chemotherapy agents.

Berberine and palmatine inhibit the growth of human rhabdomyosarcoma cells

A natural isoquinoline alkaloid, berberine, has been known to exhibit anti-tumor activity in various cancer cells via inducing cell cycle arrest. However, it has not been investigated whether berberine and its analogs inhibit the growth of rhabdomyosarcoma (RMS), which is the most frequent soft tissue tumor in children. The present study examined the anti-tumor effects of berberine and palmatine on expansions of three human embryonal RMS cell lines; ERMS1, KYM1, and RD. Intracellular incorporation of berberine was relatively higher than that of palmatine in every RMS cell line. Berberine significantly inhibited the cell cycle of all RMS cells at G1 phase. On the other hand, palmatine only suppressed the growth of RD cells. Both of berberine and palmatine strongly inhibited the growth of tumorsphere of RD cells in three-dimensional culture. These results indicate that berberine derivatives have the potential of anti-tumor drugs for RMS therapy.

Abbreviations: ARMS: alveolar rhabdomyosarcoma; ERMS: embryonal rhabdomyosarcoma; RMS: rhabdomyosarcoma

Degradation of endothelial network in disordered tumor-containing cell sheet

Tumor angiogenesis is an important event in tumor malignancy; and the vasculature formed in tumor region is typically dysfunctional. Multiple factors are associated with tumor vessel abnormalities, but the precise mechanism has not been fully understood. In the present study, a tumor-containing cell sheet was prepared by mixing a small population of human embryonal rhabdomyosarcoma (RMS) cells (RDs) with human skeletal muscle myoblasts (HSMMs) to mimic muscle tissue invaded by RMS cells. Sheet fluidity and the extracellular matrix (ECM) meshwork of the tumor-containing cell sheet were found to be elevated and disordered, demonstrating the disruptive effect of tumor cells on sheet structure. When green fluorescent protein expressing human umbilical vein endothelial cells (GFP-HUVECs) were co-cultured with the tumor-containing cell sheet, an endothelial network was formed, but degraded faster as a result of activated migration of endothelial cells in the tumor-containing cell sheet. This study suggested that disorganized tissue structure facilitate tumor angiogenesis by activation of endothelial cell migration.