# Human papillomavirus 16 E6 oncoprotein promotes up-regulation of RNA-binding protein Sam68 in head and neck cancer **Authors:** Andrea Cerasuolo, Tiziana Pecchillo Cimmino, Salvatore Gagliarde, Petra Claudia Camilla D’Orsi, Noemy Starita, Sara Amiranda, Anna Lucia Tornesello, Luisa Dassi, Patrizia Bonelli, Franca Maria Tuccillo, Franco Maria Buonaguro, Francesco Longo, Francesco Perri, Rosalia Anna Rega, Rossella De Cecio, Gerardo Ferrara, Franco Ionna, Maria Lina Tornesello PMC · DOI: 10.3389/fmicb.2026.1657818 · Frontiers in Microbiology · 2026-02-05 ## TL;DR This study shows that the HPV16 E6 oncoprotein increases the RNA-binding protein Sam68 in head and neck cancer, which may help develop new treatments. ## Contribution The study reveals a novel link between HPV16 E6*I and Sam68 overexpression in head and neck cancer. ## Key findings - SAM68 and E6*I mRNA levels are highly correlated in HPV16-related HNSCC and cell lines. - Silencing SAM68 reduces E6*I RNA and cell growth in SCC152 cells. - Higher splicing factor expression in HPV-positive HNSCC is confirmed in TCGA data. ## Abstract Head and neck squamous cell carcinoma (HNSCC) are a heterogeneous group of tumors linked to diverse risk factors, such as tobacco and alcohol use, as well as human papillomavirus (HPV) infection. HPV16 E6 and E7 oncoproteins are the main players of cell transformation, with the E6*I isoform increasing during neoplastic progression. The aim of this study was to evaluate the role of cellular splicing factors in the production of E6*I in HPV16-related HNSCC. We have evaluated the levels of splicing factors mRNA (HNRNPA1, HNRNPA2B1, SRSF1, SRSF2, SRSF3, BRM and SAM68) as well as HPV16 E6 and E6*I mRNAs by qPCR in HNSCC as well as in SCC152 and SCC154 cell lines. Overall, 42.4% of HNSCC tested positive for HPV16 DNA, and among these 54% expressed E6*I mRNA. The SRSF3, BRM and SAM68 transcripts were significantly higher in HPV-positive compared to HPV-negative HNSCC (p < 0.05), and SAM68 with HPV16 E6*I transcripts concordantly high in both HNSCC and cell lines (r = 0.7). Transduction of LXSN_E6 in HPV-negative PCA5 cell line induced production of E6*I mRNA and overexpression of Sam68 protein. In addition, silencing of SAM68 in SCC152 caused decrease of E6*I RNA and reduced cell growth at 48 hr after siRNA transfection. Higher expression of splicing factors in association with HPV was also confirmed in HNSCC TCGA dataset. In conclusion, our results suggest an interplay between the splicing machinery and HPV16 E6*I in HNSCC. These new observations are crucial for the development of novel therapeutic strategies based on SAM68 inhibitors. ## Linked entities - **Genes:** HNRNPA1 (heterogeneous nuclear ribonucleoprotein A1) [NCBI Gene 3178], HNRNPA2B1 (heterogeneous nuclear ribonucleoprotein A2/B1) [NCBI Gene 3181], SRSF1 (serine and arginine rich splicing factor 1) [NCBI Gene 6426], SRSF2 (serine and arginine rich splicing factor 2) [NCBI Gene 6427], SRSF3 (serine and arginine rich splicing factor 3) [NCBI Gene 6428], SMARCA2 (SWI/SNF related BAF chromatin remodeling complex subunit ATPase 2) [NCBI Gene 6595], KHDRBS1 (KH RNA binding domain containing, signal transduction associated 1) [NCBI Gene 10657], e6 (E6 protein) [NCBI Gene 929651] - **Proteins:** KHDRBS1 (KH RNA binding domain containing, signal transduction associated 1) - **Diseases:** head and neck squamous cell carcinoma (MONDO:0010150), HNSCC (MONDO:0010150) ## Full-text entities - **Genes:** SRSF4 (serine and arginine rich splicing factor 4) [NCBI Gene 6429] {aka SFRS4, SRP75}, TP53 (tumor protein p53) [NCBI Gene 7157] {aka BCC7, BMFS5, LFS1, P53, TRP53}, SMARCA2 (SWI/SNF related BAF chromatin remodeling complex subunit ATPase 2) [NCBI Gene 6595] {aka BAF190, BIS, BRM, NCBRS, SAMRCA2, SNF2}, SRSF5 (serine and arginine rich splicing factor 5) [NCBI Gene 6430] {aka HRS, SFRS5, SRP40}, EGF (epidermal growth factor) [NCBI Gene 1950] {aka HOMG4, URG}, SRSF2 (serine and arginine rich splicing factor 2) [NCBI Gene 6427] {aka PR264, SC-35, SC35, SFRS2, SFRS2A, SRp30b}, CASP9 (caspase 9) [NCBI Gene 842] {aka APAF-3, APAF3, ICE-LAP6, MCH6, PPP1R56}, CASP3 (caspase 3) [NCBI Gene 836] {aka CPP32, CPP32B, SCA-1}, KHDRBS1 (KH RNA binding domain containing, signal transduction associated 1) [NCBI Gene 10657] {aka Sam68, p62, p68}, CDK2 (cyclin dependent kinase 2) [NCBI Gene 1017] {aka CDKN2, p33(CDK2)}, UBE3A (ubiquitin protein ligase E3A) [NCBI Gene 7337] {aka ANCR, AS, E6-AP, EPVE6AP, HPVE6A, PIX1}, KHDRBS2 (KH RNA binding domain containing, signal transduction associated 2) [NCBI Gene 202559] {aka KHDRBS2-OT, KHDRBS2-OT1, SLM-1, SLM1}, HNRNPA1 (heterogeneous nuclear ribonucleoprotein A1) [NCBI Gene 3178] {aka ALS19, ALS20, HNRPA1, HNRPA1L3, IBMPFD3, MPD3}, VIM (vimentin) [NCBI Gene 7431], SRSF3 (serine and arginine rich splicing factor 3) [NCBI Gene 6428] {aka SFRS3, SRp20}, SRSF6 (serine and arginine rich splicing factor 6) [NCBI Gene 6431] {aka B52, HEL-S-91, SFRS6, SRP55}, PARP1 (poly(ADP-ribose) polymerase 1) [NCBI Gene 142] {aka ADPRT, ADPRT 1, ADPRT1, ARTD1, PARP, PARP-1}, HNRNPL (heterogeneous nuclear ribonucleoprotein L) [NCBI Gene 3191] {aka HNRPL, P/OKcl.14, hnRNP-L}, AKT1 (AKT serine/threonine kinase 1) [NCBI Gene 207] {aka AKT, PKB, PKB-ALPHA, PRKBA, RAC, RAC-ALPHA}, RB1 (RB transcriptional corepressor 1) [NCBI Gene 5925] {aka OSRC, PPP1R130, RB, p105-Rb, p110-RB1, pRb}, HNRNPA2B1 (heterogeneous nuclear ribonucleoprotein A2/B1) [NCBI Gene 3181] {aka HNRNPA2, HNRNPB1, HNRPA2, HNRPA2B1, HNRPB1, IBMPFD2}, KHDRBS3 (KH RNA binding domain containing, signal transduction associated 3) [NCBI Gene 10656] {aka Etle, SALP, SLM-2, SLM2, T-STAR, TSTAR}, SRSF9 (serine and arginine rich splicing factor 9) [NCBI Gene 8683] {aka SFRS9, SRp30c}, RELA (RELA proto-oncogene, NF-kB subunit) [NCBI Gene 5970] {aka AIF3BL3, CMCU, NFKB3, p65}, GAPDH (glyceraldehyde-3-phosphate dehydrogenase) [NCBI Gene 2597] {aka G3PD, GAPD, HEL-S-162eP}, GSK3B (glycogen synthase kinase 3 beta) [NCBI Gene 2932], SNAI2 (snail family transcriptional repressor 2) [NCBI Gene 6591] {aka SLUG, SLUGH, SLUGH1, SNAIL2, WS2D}, FOXO1 (forkhead box O1) [NCBI Gene 2308] {aka FKH1, FKHR, FOXO1A}, RPS6KB1 (ribosomal protein S6 kinase B1) [NCBI Gene 6198] {aka PS6K, S6K, S6K-beta-1, S6K1, STK14A, p70 S6KA}, ACTB (actin beta) [NCBI Gene 60] {aka BKRNS, BNS, BRWS1, CSMH, DDS1, PS1TP5BP1}, TGFB1 (transforming growth factor beta 1) [NCBI Gene 7040] {aka CAEND1, CED, DPD1, IBDIMDE, LAP, TGF-beta1}, LINC01296 [NCBI Gene 642477], YTHDC1 (YTH N6-methyladenosine RNA binding protein C1) [NCBI Gene 91746] {aka YT521, YT521-B}, TERT (telomerase reverse transcriptase) [NCBI Gene 7015] {aka CMM9, DKCA2, DKCB4, EST2, PFBMFT1, TCS1}, SRSF1 (serine and arginine rich splicing factor 1) [NCBI Gene 6426] {aka ASF, NEDFBA, SF2, SF2p33, SFRS1, SRp30a}, CDH2 (cadherin 2) [NCBI Gene 1000] {aka ACOGS, ADHD8, ARVD14, CD325, CDHN, CDw325}, SMAD2 (SMAD family member 2) [NCBI Gene 4087] {aka CHTD8, JV18, JV18-1, LDS6, MADH2, MADR2} - **Diseases:** HPV infection (MESH:D030361), Oral cavity and larynx SCC (MESH:D007822), oral tongue SCC (MESH:D014060), HNSCC (MESH:D000077195), SCC-9 (MESH:C557826), hepatocellular, gastric, renal, prostate, ovarian, breast, and non-small cell lung carcinoma (MESH:D002289), OCSCC (MESH:D009062), carcinogenesis (MESH:D063646), Cancer (MESH:D009369), OPSCC (MESH:D009959), HND (MESH:D006258), prostate cancer (MESH:D011471), LSCC (MESH:D007827), cervical cancer (MESH:D002583), alcohol abuse (MESH:D000437), breast cancer (MESH:D001943), ovarian cancer (MESH:D010051), infection (MESH:D007239), metastasis (MESH:D009362), HPSCC (MESH:D007012), carcinogenic (MESH:D011230), viral (MESH:D014777) - **Chemicals:** oligonucleotide (MESH:D009841), isoamyl alcohol (MESH:C029683), SDS (MESH:D012967), HCl (MESH:D006851), ethanol (MESH:D000431), phenol (MESH:D019800), water (MESH:D014867), ethidium bromide (MESH:D004996), paclitaxel (MESH:D017239), EDTA (MESH:D004492), TritonX-100 (MESH:D017830), streptomycin (MESH:D013307), polyacrylamide (MESH:C016679), N6-methyladenosine (MESH:C010223), Trypan blue (MESH:D014343), NaCl (MESH:D012965), phalloidin (MESH:D010590), sodium acetate (MESH:D019346), PBS (MESH:D007854), PVDF (MESH:C024865), alcohol (MESH:D000438), CO2 (MESH:D002245), L-glutamine (MESH:D005973), chloroform (MESH:D002725), polybrene (MESH:D006583), paraformaldehyde (MESH:C003043), Lipofectamine (MESH:C086724), Hoechst 33342 (MESH:C017807), oil (MESH:D009821), DMEM (-), cisplatin (MESH:D002945), G418 (MESH:C010680), penicillin (MESH:D010406), Alexa Fluor 647 (MESH:C569686) - **Species:** Nicotiana tabacum (American tobacco, species) [taxon 4097], Mus musculus (house mouse, species) [taxon 10090], Human papillomavirus 16 (serotype) [taxon 333760], Homo sapiens (human, species) [taxon 9606] - **Cell lines:** MCF-7 — Homo sapiens (Human), Invasive breast carcinoma of no special type, Cancer cell line (CVCL_0031), U2OS — Homo sapiens (Human), Osteosarcoma, Cancer cell line (CVCL_0042), SCC152 — Homo sapiens (Human), Hypopharyngeal squamous cell carcinoma, Cancer cell line (CVCL_C058), PA317 — Mus musculus (Mouse), Transformed cell line (CVCL_3920), SiHa — Homo sapiens (Human), Human papillomavirus-related cervical squamous cell carcinoma, Cancer cell line (CVCL_0032), HO-1N-1 — Homo sapiens (Human), Buccal mucosa squamous cell carcinoma, Cancer cell line (CVCL_1284), HeLa — Homo sapiens (Human), Human papillomavirus-related endocervical adenocarcinoma, Cancer cell line (CVCL_0030), PCA5 — Homo sapiens (Human), Squamous cell carcinoma of the penis, Cancer cell line (CVCL_VF94), PCA23 — Homo sapiens (Human), Squamous cell carcinoma of the penis, Cancer cell line (CVCL_W864), NIH-3T3 — Mus musculus (Mouse), Spontaneously immortalized cell line (CVCL_0594), LNCaP — Homo sapiens (Human), Prostate carcinoma, Cancer cell line (CVCL_0395), CAL27 — Homo sapiens (Human), Tongue adenosquamous carcinoma, Cancer cell line (CVCL_1107), SCC4 — Homo sapiens (Human), Tongue squamous cell carcinoma, Cancer cell line (CVCL_1684), SCC-25 — Homo sapiens (Human), Tongue squamous cell carcinoma, Cancer cell line (CVCL_1682), OVCAR-3 — Homo sapiens (Human), High grade ovarian serous adenocarcinoma, Cancer cell line (CVCL_0465), HT3 — Homo sapiens (Human), Cervical carcinoma, Cancer cell line (CVCL_1293), Psi2 — Mus musculus (Mouse), Transformed cell line (CVCL_2165), CAL-9 — Homo sapiens (Human), Ovarian adenocarcinoma, Cancer cell line (CVCL_5V15), NTERA2 — Homo sapiens (Human), Embryonal carcinoma, Cancer cell line (CVCL_0034), SCC154 — Homo sapiens (Human), Tongue squamous cell carcinoma, Cancer cell line (CVCL_2230), E6 — Mus musculus (Mouse), Hybridoma (CVCL_B6C7), MDA-MB-231 — Homo sapiens (Human), Breast adenocarcinoma, Cancer cell line (CVCL_0062), LXSN_E6 — Mus musculus (Mouse), Transformed cell line (CVCL_6512), LXSN — Mus musculus (Mouse), Transformed cell line (CVCL_6508) ## Full text _Full body text omitted from this summary view._ Fetch the complete paper as Markdown: https://tomesphere.com/paper/PMC12916563/full.md ## Figures 9 figures with captions in the complete paper: https://tomesphere.com/paper/PMC12916563/full.md ## References 109 references — full list in the complete paper: https://tomesphere.com/paper/PMC12916563/full.md --- Source: https://tomesphere.com/paper/PMC12916563