Establishment and Characterization of Human Oral Squamous Cell Carcinoma Cell Lines

Establishment and characterization of patient-derived tongue squamous cell carcinoma cell lines

Oral squamous cell carcinoma (OSCC) is a common carcinoma in Indian population, wherein one-third of global OSCC cases are from India. The five-year survival rate is poor due to late diagnosis. Oral tongue squamous cell carcinoma (OTSCC) is the second-most common OSCC. An in vitro cell line model is a valuable tool to get a deeper understanding of the molecular mechanisms involved in therapy resistance and disease progression. We report establishment of three OTSCC cell lines from advanced stage treatment naïve Indian patient samples, such as ACOTSC120, ACOSTC132, and ACOTSC140. All three OTSCC cell lines showed epithelial morphology, which was confirmed by Keratin-14 staining. The cell lines showed in vitro spheroid-forming and in vivo tumorigenic potential. The STR of the cell lines ensured their human origin and novelty when compared to DSMZ cell line database. The karyotype of the cell lines showed aneuploidy and further confirmed their human origin. These cell lines showed the presence of cancer stem cell (CSCs) population, i.e., the ALDHbr/CD44+ population. These cell lines thus provide a model to help understand the biology of disease and its progression.

Establishment and genomic characterization of gingivobuccal carcinoma cell lines with smokeless tobacco associated genetic alterations and oncogenic PIK3CA mutation

Smokeless tobacco associated Gingivobuccal squamous cell carcinoma (GB-SCC) is a major public health problem but available oral cancer cell lines are mostly from smoking associated tongue SCC raising the need for pertinent GB-SCC cell line models. As part of the International Cancer Genome Consortium (ICGC) Project, 4 novel cell lines, namely, Indian Tata Memorial Centre Oral Cancer (ITOC) -01 to -04 were established and characterized with conventional methods, karyotyping, ultrastructure, in vivo tumourigenicity, Whole exome sequencing (WES) and RNA sequencing. These hyperploid cell lines form xenografts in mice and show metabolically active and necrotic areas on fluorodeoxyglucose-positron emission tomography (FDG-PET) imaging. WES of ITOC cell lines recapitulate the genomic tumor profile of ICGC GB-SCC database. We further identified smokeless tobacco associated genetic alterations (PCLO, FAT3 and SYNE2) and oncogenic PIK3CA mutation in GB-SCC cell lines. Transcriptome profiling identified deregulation of pathways commonly altered in cancer and down-regulation of arachidonic acid metabolism pathway, implying its possible role in GB-SCC. Clinical application of high throughput sequencing data depends on relevant cell line models to validate potential targets. Extensively characterized, these oral SCC cell lines are particularly suited for mechanistic studies and pre-clinical drug development for smokeless tobacco associated oral cancer.

Fractionated photodynamic therapy for a human oral squamous cell carcinoma xenograft

The aim of this study was to define the appropriate fractionation interval between photodynamic therapies (PDTs) for enhanced anti-tumour effects on human oral squamous cell carcinoma (HOSCC). Reoxygenation of HOSCC and the proliferative kinetics of the tumour cells following PDT exposure were evaluated in terms of immunohistochemical expression of vascular endothelial growth factor (VEGF) and the proliferating cell nuclear antigen (PCNA). The immunohistochemical expression of VEGF was quantitatively determined by computer-assisted image analysis. The VEGF expression and the PCNA labeling indices (LIs) of the tumour cells were assessed at varying time intervals after PDT. No significant differences were observed in PCNA LIs between the control group and experimental groups at 24, 48, and 72 h after PDT. The expression of VEGF after PDT exposure was demonstrated to be higher in the experimental group at 6 h than the control group, and then was comparable at 24 h between the both groups. These results indicate that the tumour cells surviving from PDT have proliferative potential, and that oxygenation in tumours subjected to PDT may be recovered after 24 h. In the next experiment, two protocols of laser irradiation in PDT were assessed on the basis of tumour volume between fractionated exposure with a 24-h interval and continuous exposure. Regrowth of the tumour was significantly suppressed by fractionated PDT. We propose here that fractionated light exposure with a 24-h interval should be utilized in PDT for an enhanced anti-tumour effect.

Induction of apoptosis by paclitaxel in human oral carcinoma cells

The present study investigated induction of apoptosis in NB-1 oral carcinoma cells by paclitaxel and the expression of Bcl-2 and Bax in relation to this apoptotic cell death. Paclitaxel induced apoptotic cell death in NB-1 cells in a dose- and a time-dependent manner. The present results suggest that paclitaxel can induce apoptosis of NB-1 cells, which may be mediated by down-regulation of Bcl-2 together with up-regulation of Bax.