A Pilot Study of Nutritional Supplementation in Soft Tissue Sarcoma Patients.

Background: Wound healing is particularly important for sarcoma patients who undergo neoadjuvant radiation therapy. Previous studies have demonstrated wound complications in this population approaching 35%. With this high rate of wound healing issues, identifying treatment modalities to minimize these complications is of paramount importance. Methods: All patients with high grade bone and soft tissue sarcoma received 15 days of twice daily amino acid supplementation starting in the immediate post-operative period. We documented the healing status of the surgical wound, the primary outcome, at all follow up appointments until six months after surgery. Non-healing wounds were defined as any wound requiring 1) a return visit to the OR for debridement, 2) IV antibiotics (ABX), and 3) unhealed wounds at 6 months post-operatively.1 For each patient, we collected biometrics with lean body mass analysis at preoperative appointment, and two and six weeks postoperatively. The proportion with non-healing wounds was compared with a historical patient cohort using the chi-square test. In a subgroup of participants with body composition measurements, we also compared changes in mean fat mass, lean mass, and psoas index from pre-operative baseline to 6 months post-operative using generalized linear models. Results: A total of 33 consecutive patients were supplemented with a branched chain amino acid (BCAA) formulation. The historical cohort included 146 participants from the previous 7 years (2010-2017). 26% of patients in the historical cohort experienced wound complications compared to 30% in the supplemented group. (p=0.72) When focusing specifically on lower extremity sarcomas treated with neoadjuvant radiation therapy, 46% of patients in the supplemented group experienced wound healing complications compared to 39% in the non-supplemented group (p=0.68). BCAA supplementation was found to be protective with regards to decreasing muscle wasting with no difference in psoas index measurements throughout the study period compared to a 20% muscle loss in the historical cohort (p=0.02). Conclusion: In our limited sample size, there was no difference in wound healing complications between sarcoma patients who received postoperative BCAA supplementation compared to a historical cohort who were not supplemented. Patients who did not receive supplementation had a significant decline in post-operative psoas index following operative sarcoma removal. Level of Evidence: III.

RNAi screen of the protein kinome identifies checkpoint kinase 1 (CHK1) as a therapeutic target in neuroblastoma.

Neuroblastoma is a childhood cancer that is often fatal despite intense multimodality therapy. In an effort to identify therapeutic targets for this disease, we performed a comprehensive loss-of-function screen of the protein kinome. Thirty kinases showed significant cellular cytotoxicity when depleted, with loss of the cell cycle checkpoint kinase 1 (CHK1/CHEK1) being the most potent. CHK1 mRNA expression was higher in MYC-Neuroblastoma-related (MYCN)-amplified (P < 0.0001) and high-risk (P = 0.03) tumors. Western blotting revealed that CHK1 was constitutively phosphorylated at the ataxia telangiectasia response kinase target site Ser345 and the autophosphorylation site Ser296 in neuroblastoma cell lines. This pattern was also seen in six of eight high-risk primary tumors but not in control nonneuroblastoma cell lines or in seven of eight low-risk primary tumors. Neuroblastoma cells were sensitive to the two CHK1 inhibitors SB21807 and TCS2312, with median IC(50) values of 564 nM and 548 nM, respectively. In contrast, the control lines had high micromolar IC(50) values, indicating a strong correlation between CHK1 phosphorylation and CHK1 inhibitor sensitivity (P = 0.0004). Furthermore, cell cycle analysis revealed that CHK1 inhibition in neuroblastoma cells caused apoptosis during S-phase, consistent with its role in replication fork progression. CHK1 inhibitor sensitivity correlated with total MYC(N) protein levels, and inducing MYCN in retinal pigmented epithelial cells resulted in CHK1 phosphorylation, which caused growth inhibition when inhibited. These data show the power of a functional RNAi screen to identify tractable therapeutical targets in neuroblastoma and support CHK1 inhibition strategies in this disease.