CD44, γ-H2AX, and p-ATM Expressions in Short-Term Ex Vivo Culture of Tumour Slices Predict the Treatment Response in Patients with Oral Squamous Cell Carcinoma

Abstract

Squamous cell carcinoma is the most common type of head and neck cancer (HNSCC) with a disease-free survival at 3 years that does not exceed 30%. Biomarkers able to predict clinical outcomes are clearly needed. The purpose of this study was to investigate whether a short-term culture of tumour fragments irradiated ex vivo could anticipate patient responses to chemo- and/or radiotherapies. Biopsies were collected prior to treatment from a cohort of 28 patients with non-operable tumours of the oral cavity or oropharynx, and then cultured ex vivo. Short-term biopsy slice culture is a robust method that keeps cells viable for 7 days. Different biomarkers involved in the stemness status (CD44) or the DNA damage response (pATM and γ-H2AX) were investigated for their potential to predict the treatment response. A higher expression of all these markers was predictive of a poor response to treatment. This allowed the stratification of responder or non-responder patients to treatment. Moreover, the ratio for the expression of the three markers 24 h after 4 Gy irradiation versus 0 Gy was higher in responder than in non-responder patients. Finally, combining these biomarkers greatly improved their predictive potential, especially when the γ-H2AX ratio was associated with the CD44 ratio or the pATM ratio. These results encourage further evaluation of these biomarkers in a larger cohort of patients.

Recent advances in organotypic tissue slice cultures for anticancer drug development

“…Organotypic tumor slice culture demonstrates the suitability to investigate the antitumor activity of small-molecule drug therapy (i.e., chemotherapy and molecularly targeted therapy) [24,25,27,41,47,49,[66][67][68][69][70][71][72][73][74][75][76][77][78][79][80][81][82][83][84], immunotherapy [27,31,85], radiotherapy [86][87][88], and adoptive cellular therapy [32], as summarized in Table 3 and discussed below.…”

“…Increase in cell loss and apoptosis [49] Hepatocellular carcinoma Sorafenib plus N20 blocking peptide Oral squamous cell carcinoma 4 Gy irradiation 28 More cancer stem cells and DNA damage response in responders than nonresponders [87] *The "or"-connected drugs represent monotherapy, while the "plus"-connected drugs represent combination therapy. ‡These 7 patients consist of 2 breast cancer patients and 5 colon cancer patients, and these 37 patients consist of 13 melanoma patients, 7 NSLCC patients, 8 breast cancer patients, 6 ovarian patients, and 3 RCC patients.…”

“…Cancer stem cell status and DNA damage repair both dictate tumor radioresistance. After 24 hours of exposure to 4 Gy irradiation, the expression levels of the cancer stem cell marker CD44 and DNA damage repair markers γ-H2AX and p-ATM in tumor slices from radiotherapy-sensitive oral squamous cell carcinoma patients are significantly higher than those from radiotherapy-resistant patients 87 , suggesting that this platform is applicable to stratify radiotherapeutic responders from nonresponders. Radiotherapy plus the inhibitor of cyclin-dependent kinases 4 and 6 (CDK4/6i) palbociclib contribute to a significantly increased cell death in meningioma slices than either of the monotherapy 88 .…”

Ex vivoprimary liver sections recapitulate disease phenotype and therapeutic rescue for liver monogenic diseases

“…vibratome [8], has allowed a transition from manually cut slices characterised by heterogeneous width and poor survival rate to reproducible thinner slices with better preserved structural integrity, further facilitated the optimisation of culture conditions such as appropriate oxygen and nutrients. PCTS has been generated from various organs such as liver [9], intestines [10, 11], colon [10], brain [12, 13], lung [7, 14, 15], kidney [16, 17], spleen [18, 19], heart [20, 21] and tumours [22, 23]. They can also originate from various animal models such as mouse [9], rat [24, 25], pig [26] and human surgical wastes [22, 27, 28].…”

“…PCTS has been generated from various organs such as liver [9], intestines [10,11], colon [10], brain [12,13], lung [7,14,15], kidney [16,17], spleen [18,19], heart [20,21] and tumours [22,23]. They can also originate from various animal models such as mouse [9], rat [24,25], pig [26] and human surgical wastes [22,27,28].…”