The antitumor efficacy of monomeric disintegrin obtustatin in S-180 sarcoma mouse model.

Obtustatin, isolated from the Levantine Viper snake venom (Macrovipera lebetina obtusa -MLO), is the shortest known monomeric disintegrin shown to specifically inhibit the binding of the α1ß1 integrin to collagen IV. Its oncostatic effect is due to the inhibition of angiogenesis, likely through α1ß1 integrin inhibition in endothelial cells. To explore the therapeutic potential of obtustatin, we studied its effect in S-180 sarcoma-bearing mice model in vivo as well as in human dermal microvascular endothelial cells (HMVEC-D) in vitro, and tested anti-angiogenic activity in vivo using the chick embryo chorioallantoic membrane assay (CAM assay). Our in vivo results show that obtustatin inhibits tumour growth by 33%. The expression of vascular endothelial growth factor (VEGF) increased after treatment with obtustatin, but the level of expression of caspase 8 did not change. In addition, our results demonstrate that obtustatin inhibits FGF2-induced angiogenesis in the CAM assay. Our in vitro results show that obtustatin does not exhibit cytotoxic activity in HMVEC-D cells in comparison to in vivo results. Thus, our findings disclose that obtustatin might be a potential candidate for the treatment of sarcoma in vivo with low toxicity.

Drug repurposing: mebendazole as effective antitumor agent. Are we seeing the whole story?

PURPOSE: To examine the antitumor effects of Mebendazole (MZ) in a model of experimental fibrosarcoma induced by inoculation of BHK-21/C13 cells in Syrian golden hamster. METHODS: Hamsters were inoculated with a suspension of BHK cells by subcutaneous injection and randomly divided into 5 experimental and 2 control groups. Treatment started on the 10th day after inoculation, when the tumor grew to a diameter of 5mm. The experimental design was based on distributing the total amount of drug MZ(z) in different protocols and approaches (oral/intraperitoneal) to the 5 experimental groups. The positive control group received doxorubicin intraperitoneally. Negative control group received olive oil orally. The total amount of MZ(z) was chosen to be the highest for the animal to survive during the experiment. For antitumor effect evaluation, the main parameters were tumor size, number of mitoses, cytochrome-C immunopositivity and tumor tissue morphology incuding cytoarchitecture and percentage of preserved tumor tissue in stereologically reconstructed tumor mass. RESULTS: The results of this study showed absence of objective MZ antitumor effect on experimental fibrosarcoma. MZ does not exhibit activity similar to DNA-damaging agents on the fibrosarcoma model. CONCLUSIONS: It might be postulated that soft tissue tumors on animal models could show high level of resistance to MZ effect.

A novel colchicine-based microtubule inhibitor exhibits potent antitumor activity by inducing mitochondrial mediated apoptosis in MIA PaCa-2 pancreatic cancer cells.

Colchicine, an antimitotic alkaloid isolated from Colchicum autumnale, is a classical drug for treatment of gout and familial Mediterranean fever. It causes antiproliferative effects through the inhibition of microtubule formation, which leads to mitotic arrest and cell death by apoptosis. Here, we report that a novel colchicine analog, 4o (N-[(7S)-1,2,3-trimethoxy-9-oxo-10-[3-(trifluoromethyl)-4-chlorophenylamino]-5,6,7,9-tetrahydrobenzo[a]heptalen-7-yl]acetamide), which exhibited potent anticancer activities both in vitro and in vivo. In this study, 4o with excellent pharmacokinetic profile and no P-gp induction liability displayed strong inhibition of proliferation against various human cancer cell lines. However, pancreatic cancer cell line MIA PaCa-2 was found to be more sensitive towards 4o and showed strong inhibition in concentration and time-dependent manner. By increasing intracellular reactive oxygen species (ROS) levels, 4o induced endoplasmic reticular stress and mitochondrial dysfunction in MIA PaCa-2 cells. Blockage of ROS production reversed 4o-induced endoplasmic reticulum (ER) stress, calcium release, and cell death. More importantly, it revealed that increased ROS generation might be an effective strategy in treating human pancreatic cancer. Further 4o treatment induced mitotic arrest, altered the expression of cell cycle-associated proteins, and disrupted the microtubules in MIA PaCa-2 cells. 4o treatment caused loss of mitochondrial membrane potential, cytochrome c release, upregulation of Bax, downregulation of Bcl-2, and cleavage of caspase-3, thereby showing activation of mitochondrial mediated apoptosis. The in vivo anticancer activity of the compound was studied using sarcoma-180 (ascitic) and leukemia (P388 lymphocytic and L1210 lymphoid) models in mice and showed promising antitumor activity with the least toxicity unlike colchicine. Such studies have hitherto not been reported. Taken together, these findings highlighted that 4o, a potent derivative of colchicine, causes tumor regression with reduced toxicity and provides a novel anticancer candidate for the therapeutic use.

Pronounced Cellular Uptake of Pirarubicin versus That of Other Anthracyclines: Comparison of HPMA Copolymer Conjugates of Pirarubicin and Doxorubicin.

Many conjugates of water-soluble polymers with biologically active molecules were developed during the last two decades. Although, therapeutic effects of these conjugates are affected by the properties of carriers, the properties of the attached drugs appear more important than the same carrier polymer in this case. Pirarubicin (THP), a tetrahydropyranyl derivative of doxorubicin (DOX), demonstrated more rapid cellular internalization and potent cytotoxicity than DOX. Here, we conjugated the THP or DOX to N-(2-hydroxypropyl)methacrylamide copolymer via a hydrazone bond. The polymeric prodrug conjugates, P-THP and P-DOX, respectively, had comparable hydrodynamic sizes and drug loading. Compared with P-DOX, P-THP showed approximately 10 times greater cellular uptake during a 240 min incubation and a cytotoxicity that was more than 10 times higher during a 72-h incubation. A marginal difference was seen in P-THP and P-DOX accumulation in the liver and kidney at 6 h after drug administration, but no significant difference occurred in the tumor drug concentration during 6-24 h after drug administration. Antitumor activity against xenograft human pancreatic tumor (SUIT2) in mice was greater for P-THP than for P-DOX. To sum up, the present study compared the biological behavior of two different drugs, each attached to an N-(2-hydroxypropyl)methacrylamide copolymer carrier, with regard to their uptake by tumor cells, body distribution, accumulation in tumors, cytotoxicity, and antitumor activity in vitro and in vivo. No differences in the tumor cell uptake of the polymer-drug conjugates, P-THP and P-DOX, were observed. In contrast, the intracellular uptake of free THP liberated from the P-THP was 25-30 times higher than that of DOX liberated from P-DOX. This finding indicates that proper selection of the carrier, and especially conjugated active pharmaceutical ingredient (API) are most critical for anticancer activity of the polymer-drug conjugates. THP, in this respect, was found to be a more preferable API for polymer conjugation than DOX. Hence the treatment based on enhanced permeability and retention (EPR) effect that targets more selectively to solid tumors can be best achieved with THP, although both polymer conjugates of DOX and THP exhibited the EPR effects and drug release profiles in acidic pH similarly.

Initial testing (stage 1) of the tubulin binding agent nanoparticle albumin-bound (nab) paclitaxel (Abraxane(®)) by the Pediatric Preclinical Testing Program (PPTP).

BACKGROUND: Nanoparticle albumin-bound paclitaxel (nab-paclitaxel, Abraxane(®)) is FDA approved for the treatment of several adult cancers. Antimitotic agents are essential components for curative therapy of pediatric solid tumors, although taxanes have shown limited activity. Because of the novel formulation, nab-paclitaxel was evaluated against a limited series of Pediatric Preclinical Testing Program (PPTP) solid tumors. PROCEDURES: Nab-paclitaxel was tested against a limited subset of PPTP solid tumor xenograft models at a dose of 50 mg/kg using a q4d × 3 schedule intravenously. RESULTS: Nab-paclitaxel was well tolerated in vivo, producing maximum weight loss of approximately 10% with recovery to baseline weight in the week following the third dose. All 20 xenograft models tested were considered evaluable for efficacy. Nab-paclitaxel induced statistically significant differences in event-free survival (EFS) distribution compared to control in 19 of 20 (95%) of the solid tumors. Objective responses were observed in 12 of 20 (60%) solid tumor xenografts. Complete responses (CR) or maintained CR were observed in 5 of 8 Ewing sarcoma models and 6 of 8 rhabdomyosarcomas. There were no objective regressions in either neuroblastoma (n = 2) or osteosarcoma (n = 2) xenograft panels. At the dose tested, systemic exposures of nab-paclitaxel in mice were somewhat greater than those tolerated in humans. CONCLUSIONS: The high level of activity observed against the rhabdomyosarcoma and Ewing sarcoma PPTP preclinical models makes nab-paclitaxel an interesting agent to consider for pediatric evaluation.

[Certain results of the investigations into the anti-tumour action of the magnetic field under experimental conditions].

This paper summarizes the results of the application of thr magnetic fields for the treatment of experimental tumours, such as sarcoma M-1, alveolar liver cancer PC-1, and Erlich's carcinoma. The evidence of the anti-tumour action of both strong (1200 mTI) and weak (5 to 100 mTI) magnetic fields has been obtained. The author describes the modulating effect of the magnetic fields on the anti-tumour potency of photodynamic therapy and chemotherapy. The data concerning the impact of ferromagnetic hyperthermal therapy on the tumour growth and the survival rate among the tumour-bearing animals are presented.

Photodynamic therapy of experimental sarcoma M-1 with boronated chlorine as a photosensitizer.

Using rat model of experimental sarcoma M-1 we studied the efficacy of photodynamic therapy with boronated chlorine as a photosensitizer in doses of 1.25, 2.5, 5.0, and 10.0 mg/ kg body weight. Laser irradiation was performed at energy densities of 150, 300 J/cm(2) and power density of 0.25 and 0.42 W/cm(2). Treatment efficacy was evaluated by the percentage of animals with complete tumor regression, percentage of tumor recurrence and, in cases of its growth, by tumor growth coefficient. The efficacy of photodynamic therapy depended on the dose of boronated chlorine and parameters of the laser irradiation. Optimal conditions were the dose of 2.5 mg/kg at laser energy density of 300 J/cm(2) and power density of 0.42 W/cm(2) and a dose of 5.0 mg/kg at 150 J/cm(2) and 0.25 W/cm(2).

[The effect of sodium fluoroacetate and metformin on the antitumor activity of cyclophosphamide on the autochthonous mice sarcoma model].

Previously it was found that sodium fluoroacetate (SF) inhibited the growth of the Ehrlich cancer by means of monotherapy and enhanced the antitumor effect of cyclophosphamide (CP) in experiments with autochthonous subcutaneous tumors induced by benzo (a) pyrene. In this study a comparison of the antitumor activity of SF and metformin showed that both substances did not have significant effect in monotherapy but enhanced the effect of CP, increasing the percentage of tumors with the same or reduced volume. Besides, SF, unlike metformin increased the average duration of effect. The data obtained promoted further study of the mechanism of the antitumor effect of SF and the search effective combination with already known antitumor drugs.

[Effect of epsilon-aminocaproic acid, cyclophosphamide and their combination on the growth of autochthonous sarcomas of mice induced by benzo(a)pyrene].

Antifibrinolytic drug epsilon-aminocaproic acid as a therapeutic form (5% solution in saline) was tested for antitumor activity in the autochthonous subcutaneous tumors of mice, induced by benzo (a) pyrene, in monotherapy mode (instead animals received drinking water) and in combination with cyclophosphamide, which was administered once intraperitoneally in the dose of 200 mg/kg. In the control groups, treated with drinking water and saline solution instead of water, there was no stabilization and reduction in tumor volume, while in the groups receiving epsilon-aminocaproic acid, cyclophosphamide and their combination statistically significantly in comparison with the control groups there was increased the proportion of tumors with not changed or reduced volume; epsilon-aminocaproic acid enhanced the antitumor effect of cyclophosphamide. The data obtained are for further study of the antitumor effect of epsilon-aminocaproic acid.

cRGD-functionalized polymeric magnetic nanoparticles as a dual-drug delivery system for safe targeted cancer therapy.

In this paper we give a method of integrated treatment for cancer and drug-induced complications in the process of cancer therapy through dual-drug delivery system (DDDS). Two hydrophilic drugs, doxorubicin (an antitumor drug) and verapamil (an antiangiocardiopathy drug) combined preliminarily with chitosan shell coated on magnetic nanoparticles (MNPs), followed by entrapping into the PLGA nanoparticles. Further modification was conducted by conjugating tumor-targeting ligand, cyclo(Arg-Gly-Asp-D-Phe-Lys) (c(RGDfK)) peptide, onto the end carboxyl groups on the PLGA-NPs. The size of the resulting cRGD-DOX/VER-MNP-PLGA NPs was approximately 144nm under simulate physiological environment. Under present experiment condition, the entrapment efficiencies of DOX and VER were approximately 74.8 and 53.2wt% for cRGD-DOX/VER-MNP-PLGA NPs. This paper contains interesting pilot data such as NIR-triggered drug release, in vivo drug distribution studies and whole-mouse optical imaging. Histopathological examinations and electrocardiogram comparison demonstrated that the intelligent DDDS could markedly inhibit the growth of tumor and potentially offer an approach for safe cancer therapy.

Extra-hepatic cancer represses hepatic drug metabolism via interleukin (IL)-6 signalling.

PURPOSE: In many cancer patients, the malignancy causes reduced hepatic drug clearance leading to potentially serious complications from the use of anticancer drugs. The mechanisms underlying this phenomenon are poorly understood. We aimed to identify tumor-associated inflammatory pathways that alter drug response and enhance chemotherapy-associated toxicity. METHODS: We studied inflammatory pathways involved in extra-hepatic tumor mediated repression of CYP3A, a major hepatic drug metabolizing cytochrome P450 subfamily, using a murine Engelbreth-Holm-Swarm sarcoma model. Studies in IL-6 knockout mice determined the source of elevated IL-6 in tumor-bearing animals and monoclonal antibodies against IL-6 were used to intervene in this inflammatory pathway. RESULTS: Our studies confirm elevated plasma IL-6 levels and reveal activation of Jak/Stat and Mapk signalling pathways and acute phase proteins in livers of tumor-bearing mice. Circulating IL-6 was predominantly produced by the tumor xenograft, rather than being host derived. Anti IL-6 antibody intervention partially reversed tumor-mediated inflammation and Cyp3a gene repression. CONCLUSIONS: IL-6 is an important player in cancer-related repression of CYP3A-mediated drug metabolism and activation of the acute phase response. Targeting IL-6 in cancer patients may prove an effective approach to alleviating cancer-related phenomena, such as adverse drug-related outcomes commonly associated with cancer chemotherapy.

Preparation, characterization and anticancer therapeutic efficacy of cisplatin-loaded niosomes.

This study developed a carrier for anticancer drug, cisplatin. Cisplatin-loaded niosomes (CP-NMs) were prepared under optimized conditions with Span 40 and cholesterol as the excipients, and then lyophilized and characterized. Their anticancer efficacy was tested in rabbits bearing VX2 sarcoma. The obtained spherical-looking vesicles showed a diameter of 7.73 ± 1.49 µm with a zeta-potential of 0 mV. The entrapment efficiency was 76.93 ± 2.67%, and drug loading 2.96 ± 0.10%. In vitro release tests gave a t50% of 8.36 h. The rabbits locally injected with the CP-NMs gave significantly superior results of inhibition of tumour growth, much lower mortality and improved results of body weight change and inhibition of tumour metastasis to inguinal lymph nodes and liver compared to those treated in the same way with the drug solution. The inspiring anticancer results indicated that the CP-NMs might be developed as an effective anticancer preparation with low toxicity.

Signs of cell-cell interactions in sarcoma 45 tissue under conditions of antitumor effect caused by injection of magnetite nanoparticles.

Changes in transplanted sarcoma 45 tissue in outbred albino rats with tumor regression under the effect of magnetite nanoparticles (magnetic fluid) were studied by light and electron microscopy. The ultrastructure and cell death types in regressing tumors and signs of cell-cell interactions with participation of macrophages, lymphocytes, neutrophils, and degranulating mast cells were described. Some possible mechanisms of a pronounced antitumor activity of magnetite nanoparticles were discussed.

[Effect of sodium fluoroacetate on Ehrlich solid tumor and autochthonous sarcoma growth in mice].

Due to biochemical characteristics of toxic action of fluoroacetate on energetics and metabolism of cells, including tumor cells, it was interesting to testify sodium fluoroacetate (SFA) for its antitumor activity in vivo. We have estimated that SFA significantly inhibits growth of Ehrlich tumor carcinoma. In experiments with autochthonous induced by benzo[a]pyrene subcutaneous tumors, SFA was not active in monotherapy regime, though potentiated antitumor effect of cyclophosphamide, significantly increasing the relative number of mice with stabilized or decreased tumor volume as well as the duration of this effect. The data obtained render basis for additional studies of mechanism of antitumor effect of SFA.

Antiangiogenic effects of GFP08, an agaran-type polysaccharide isolated from Grateloupia filicina.

An agaran-type polysaccharide, GFP08, isolated from Grateloupia filicina (C. Agardh) Lamouroux, was mainly composed of 1,3-linked ß-D-galactose partially sulfated at position O-2 and 1,4-linked α-L-galactose O-2, O-3-disulfate, α-L-galactose O-6-sulfate and 3,6-anhydro-α-L-galactose. Small quantities of xylose, 4,6-O-(1'-carboxyethylidene) and 6-O-methyl-ß-D-galactose were also present. In mice bearing sarcoma-180 cells, GFP08 decreased tumor weight in a dose-dependent manner. The antiangiogenic activity of GFP08 was evaluated using the chicken chorioallantoic membrane assay, and the results showed that GFP08 dose-dependently reduced new vessel formation. Meanwhile, GFP08 inhibited the differentiation of human umbilical vein endothelial cells (HUVECs) into capillary-like structures in vitro and reduced the number of migrated cells. However, there was no observed cytotoxicity of GFP08 toward HUVECs. Further study revealed that GFP08 decreased tissue factor (TF) expression without affecting the activities of matrix metalloproteinase-2 and -9. All those data indicated that GFP08 had an antitumor effect that might be associated in part with its antiangiogenic effect through down-regulating the expression of TF protein.

Support of a free radical mechanism for enhanced antitumor efficacy of the microtubule disruptor OXi4503.

Unlike normal blood vessels, the unique characteristics of an expanding, disorganized and leaky tumor vascular network can be targeted for therapeutic gain by vascular disrupting agents (VDAs), which promote rapid and selective collapse of tumor vessels, causing extensive secondary cancer cell death. A hallmark observation following VDA treatment is the survival of neoplastic cells at the tumor periphery. However, comparative studies with the second generation tubulin-binding VDA OXi4503 indicate that the viable rim of tumor tissue remaining following treatment with this agent is significantly smaller than that seen for the lead VDA, combretastatin. OXi4503 is the cis-isomer of CA1P and it has been speculated that this agent's increased antitumor efficacy may be due to its reported metabolism to orthoquinone intermediates leading to the formation of cytotoxic free radicals. To examine this possibility in situ, KHT sarcoma-bearing mice were treated with either the cis- or trans-isomer of CA1P. Since both isomers can form quinone intermediates but only the cis-isomer binds tubulin, such a comparison allows the effects of vascular collapse to be evaluated independently from those caused by the reactive hydroxyl groups. The results showed that the cis-isomer (OXi4503) significantly impaired tumor blood flow leading to secondary tumor cell death and >95% tumor necrosis 24h post drug exposure. Treatment with the trans-isomer had no effect on these parameters. However, the combination of the trans-isomer with combretastatin increased the antitumor efficacy of the latter agent to near that of OXi4503. These findings indicate that while the predominant in vivo effect of OXi4503 is clearly due to microtubule collapse and vascular shut-down, the formation of toxic free radicals likely contributes to its enhanced potency.

Viral vector transduction of the human deoxycytidine kinase cDNA sensitizes glioma cells to the cytotoxic effects of cytosine arabinoside in vitro and in vivo.

Cytosine arabinoside (ara-C) is a cytidine analog that incorporates into replicating DNA and induces lethal DNA strand breaks. Although ara-C is a potent antitumor agent for hematologic malignancies, it has only minimal activity against most solid tumors. The rate-limiting step in intracellular ara-C activation is phosphorylation of the prodrug by deoxycytidine kinase (dCK). The present results demonstrate that both retroviral and adenoviral vector-mediated transduction of the dCK cDNA results in marked sensitization of glioma cells lines to the cytotoxic effects of ara-C in vitro. We also demonstrate that ara-C treatment of established intradermal and intracerebral gliomas transduced with dCK results in significant antitumor effects in vivo. These data suggest that viral vector transduction of the dCK gene followed by treatment with ara-C represents a new chemosensitization strategy for cancer gene therapy.

[Effect of monochromatic red lighting potentiating antitumor action of cyclophosphamide injected with autoblood].

Blood was sampled from the caudal vein of rats, incubated with cyclophosphamide with autoblood, exposed to red light (0.31 Jcm2) and re-injected into the femoral vein. Lighting in conjunction with the antitumor action of the drug was followed by significant inhibition of large-size tumors, longer survival and development of integral criteria which describe cumulative antitumor effect.

Nitric oxide synthase inhibition enhances the tumor vascular-damaging effects of combretastatin a-4 3-o-phosphate at clinically relevant doses.

PURPOSE: The therapeutic potential of combining the prototype tumor vascular-disrupting agent combretastatin A-4 3-O-phosphate (CA-4-P) with systemic nitric oxide synthase (NOS) inhibition was investigated preclinically. EXPERIMENTAL DESIGN: Vascular response (uptake of (125)I-labeled iodoantipyrine; laser Doppler flowmetry) and tumor response (histologic necrosis; cytotoxicity and growth delay) were determined. RESULTS: Inducible NOS selective inhibitors had no effect on blood flow in the P22 rat sarcoma. In contrast, the non-isoform-specific NOS inhibitor N(omega)-nitro- l-arginine (l-NNA; 1 and 10 mg/kg i.v. or chronic 0.1 or 0.3 mg/mL in drinking water) decreased the P22 blood flow rate selectively down to 36% of control at 1 hour but did not induce tumor necrosis at 24 hours. CA-4-P, at clinically relevant doses, decreased the P22 blood flow rate down to 6% of control at 1 hour for 3 mg/kg but with no necrosis induction. However, l-NNA administration enhanced both CA-4-P-induced tumor vascular resistance at 1 hour (chronic l-NNA administration) and necrosis at 24 hours, with 45% or 80% necrosis for 3 and 10 mg/kg CA-4-P, respectively. Bolus l-NNA given 3 hours after CA-4-P was the most effective cytotoxic schedule in the CaNT mouse mammary carcinoma, implicating a particular enhancement by l-NNA of the downstream consequences of CA-4-P treatment. Repeated dosing of l-NNA with CA-4-P produced enhanced growth delay over either treatment alone in P22, CaNT, and spontaneous T138 mouse mammary tumors, which represented a true therapeutic enhancement. CONCLUSIONS: The combination of NOS inhibition with CA-4-P is a promising approach for targeting tumor vasculature, with relevance for similar vascular-disrupting agents in development.

Combining PCI-24781, a novel histone deacetylase inhibitor, with chemotherapy for the treatment of soft tissue sarcoma.

PURPOSE: Histone deactylase inhibitors (HDACi) are a promising new class of anticancer therapeutics; however, little is known about HDACi activity in soft tissue sarcoma (STS), a heterogeneous cohort of mesenchymal origin malignancies. Consequently, we investigated the novel HDACi PCI-24781, alone/in combination with conventional chemotherapy, to determine its potential anti-STS-related effects and the underlying mechanisms involved. EXPERIMENTAL DESIGN: Immunoblotting was used to evaluate the effects of PCI-24781 on histone and nonhistone protein acetylation and expression of potential downstream targets. Cell culture-based assays were utilized to assess the effects of PCI-24781 on STS cell growth, cell cycle progression, apoptosis, and chemosensitivity. Quantitative reverse transcription-PCR, chromatin immunoprecipitation, and reporter assays helped elucidate molecular mechanisms resulting in PCI-24781-induced Rad51 repression. The effect of PCI-24781, alone or with chemotherapy, on tumor and metastatic growth was tested in vivo using human STS xenograft models. RESULTS: PCI-24781 exhibited significant anti-STS proliferative activity in vitro, inducing S phase depletion, G(2)/M cell cycle arrest, and increasing apoptosis. Superior effects were seen when combined with chemotherapy. A PCI-24781-induced reduction in Rad51, a major mediator of DNA double-strand break homologous recombination repair, was shown and may be a mechanism underlying PCI-24781 chemosensitization. We showed that PCI-24781 transcriptionally represses Rad51 through an E2F binding-site on the Rad51 proximal promoter. Although single-agent PCI-24781 had modest effects on STS growth and metastasis, marked inhibition was observed when combined with chemotherapy. CONCLUSIONS: In light of these findings, this novel molecular-based combination may be applicable to multiple STS histologic subtypes, and potentially merits rigorous evaluation in human STS clinical trials.