Cancer Stem Cell Subpopulations Are Present Within Metastatic Head and Neck Cutaneous Squamous Cell Carcinoma

Abstract

Cancer stem cells (CSCs) have been identified in many cancer types including primary head and neck cutaneous squamous cell carcinoma (HNcSCC). This study aimed to identify and characterize CSCs in metastatic HNcSCC (mHNcSCC). Immunohistochemical staining performed on mHNcSCC samples from 15 patients demonstrated expression of the induced pluripotent stem cell (iPSC) markers OCT4, SOX2, NANOG, KLF4, and c-MYC in all 15 samples. In situ hybridization and RT-qPCR performed on four of these mHNcSCC tissue samples confirmed transcript expression of all five iPSC markers. Immunofluorescence staining performed on three of these mHNcSCC samples demonstrated expression of c-MYC on cells within the tumor nests (TNs) and the peri-tumoral stroma (PTS) that also expressed KLF4. OCT4 was expressed on the SOX2+/NANOG+/KLF4+ cells within the TNs, and the SOX2+/NANOG+/KLF4+ cells within the PTS. RT-qPCR demonstrated transcript expression of all five iPSC markers in all three mHNcSCC-derived primary cell lines, except for SOX2 in one cell line. Western blotting showed the presence of SOX2, KLF4, and c-MYC but not OCT4 and NANOG in the three mHNcSCC-derived primary cell lines. All three cell lines formed tumorspheres, at the first passage. We demonstrated an OCT4+/NANOG+/SOX2+/KLF4+/c-MYC+ CSC subpopulation and an OCT4+/NANOG-/SOX2+/KLF4+/c-MYC+ subpopulation within the TNs, and an OCT4+/NANOG+/SOX2+/KLF4+/c-MYC+ subpopulation within the PTS of mHNcSCC.

Cancer Stem Cells in Metastatic Head and Neck Cutaneous Squamous Cell Carcinoma Express Components of the Renin-Angiotensin System

“…There is increasing evidence of the role of the RAS in tumorigenesis, and metastasis [ 23 , 24 , 57 ]. We have recently demonstrated the presence of CSC subpopulations that express the ESC markers OCT4, NANOG, SOX2, KLF4, and c-MYC in primary HNcSCC [ 19 ] and mHNcSCC [ 20 ]. In this study we have shown expression of five components of the RAS: angiotensinogen, PRR, ACE, AT 1 R, and AT 2 R, in mHNcSCC tissue samples.…”

“…mHNcSCC tissue samples from 20 patients aged 51–87 (mean, 77.7) years ( Table S1 ), including those used in our previous study [ 20 ], were sourced from the Gillies McIndoe Research Institute Tissue Bank. This study was approved by the Central Regional Health and Disability Ethics Committee (Ref.…”

“…CSCs can be identified by their expression of embryonic stem cell (ESC) markers [ 9 ] and have been demonstrated in many cancer types [ 7 ], including oral cavity SCC (OCSCC) of different subsites [ 10 , 11 , 12 , 13 ], glioblastoma [ 8 ], renal clear cell carcinoma [ 14 ], primary [ 15 ] and metastatic [ 16 ] colon adenocarcinoma, and metastatic malignant melanoma to regional lymph nodes [ 17 ] and the brain [ 18 ]. We recently showed the presence of CSC subpopulations within primary head and neck cutaneous SCC (HNcSCC) [ 19 ] and metastatic HNcSCC (mHNcSCC) [ 20 ]. These CSC subpopulations within primary HNcSCC and mHNcSCC express ESC markers OCT4, SOX2, KLF4, NANOG and c-MYC [ 9 , 10 ], which are involved in the induction of pluripotent stem cells [ 9 ].…”

“…We have recently demonstrated the expression of components of the RAS: PRR, ACE, AT 1 R, and AT 2 R by the CSCs in different cancer types, including OCSCC of different subsites [ 47 , 48 ], glioblastoma [ 8 ], metastatic malignant melanoma to the brain [ 18 ] and regional nodes [ 49 ], metastatic colon adenocarcinoma [ 50 ], and primary HNcSCC [ 51 ]. This study aimed to investigate the expression of components of the RAS: angiotensinogen, renin, PRR, ACE, ACE2, AT 1 R, and AT 2 R, in relation to the CSC subpopulations we have identified in mHNcSCC [ 20 ].…”

Association of CD44−/CD24−Breast Cancer Cells with Late Stage Tumor Recurrence

“…It is made available under a preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in The copyright holder for this this version posted December 7, 2020. ; https://doi.org/10.1101/2020.12.07.414599 doi: bioRxiv preprint 13 2006; Wei et al, 2019). Although the underlying molecular mechanisms remain to be defined, CSC plasticity and heterogeneity could induce tumor progression and resistance to therapy (Das et al, 2020;Kilmister et al, 2020;Martin-Castillo et al, 2013;Thankamony et al, 2020). For example, intratumoral heterogeneity is a major ongoing challenge for effective cancer therapy, while CSCs are responsible for intratumoral heterogeneity, therapeutic resistance, and metastasis, which may be because cancer cells exhibit a high level of plasticity and an ability to dynamically switch between CSC and non-CSC states or among different subsets of CSCs (Thankamony et al, 2020).…”