SPHINX31 suppresses splicing factor phosphorylation and inhibits melanoma cell growth and aggressiveness


  • Jesadagorn Siriwath Department of Biochemistry, Faculty of Medical Sciences, Naresuan University, Phitsanulok 65000, Thailand
  • Natsupa Wiriyakulsit Department of Biochemistry, Faculty of Medical Sciences, Naresuan University, Phitsanulok 65000, Thailand
  • Patcharee Klomkleang Department of Biochemistry, Faculty of Medical Sciences, Naresuan University, Phitsanulok 65000, Thailand
  • Chaturong Inpad Department of Biochemistry, Faculty of Medical Sciences, Naresuan University, Phitsanulok 65000, Thailand
  • Sittiruk Roytrakul National Center for Genetic Engineering and Biotechnology (BIOTEC), Klong Luang, Pathumthani 12120, Thailand
  • Worasak Kaewkong Department of Biochemistry, Faculty of Medical Sciences, Naresuan University, Phitsanulok 65000, Thailand


alternative splicing, cancer phenotype, melanoma, phosphorylation, splicing factor, SRPK1


Melanoma is a tumor resulting from the malignant transformation of skin or ocular melanocytes, and a serious health problem in countries with high UV exposure.  The late detection, high invasive and metastatic potential of melanoma cells, and lack of effective treatments have led to poor prognosis and a high mortality rate among melanoma patients.  The aberrant mRNA transcripts derived from alternative splicing have contributed to the progression of various types of cancer.  Serine/Arginine-rich Splicing Factors (SRSFs) are responsible for mRNA splicing under the specific regulation of Serine-Arginine Protein Kinases (SRPKs).  This study investigates the effects of the SRPK1-specific inhibitor SPHINX31.  Cell viability was determined in A375 (cutaneous melanoma cell) in comparison to 92-1 (ocular melanoma cell) by MTT viability assays.  The inhibitory effect of SPHINX31 on melanoma cell viability is presented in a dose- and time-dependent manner, with western blot analysis then performed to observe the suppression of kinase activity by SPHINX31.  A decrease in phosphorylated SRSFs (pSRSFs) was demonstrated by both cells.  The growth inhibition of SPHINX31 was examined by clonogenic assay, with the size and number of both A375 and 92-1 cell colonies decreasing.  Remarkably, the results of SPHINX31 in other cancer phenotypes studies on A375 cells showed a significant effect on growth inhibition.  The findings of this study reveal that SPHINX31 reduces the dead-evasion and migration abilities of the A375 cell.  The collected data should serve as a strong foundation for developing new alternative therapeutic strategies for melanoma treatment by targeting SRPK1 activation.


Änkö, M. L., Müller-McNicoll, M., Brandl, H., Curk, T., Gorup, C., Henry, I., ... & Neugebauer, K. M. (2012). The RNA-binding landscapes of two SR proteins reveal unique functions and binding to diverse RNA classes. Genome Biology, 13(3), 1-17.

Batson, J., Toop, H. D., Redondo, C., Babaei-Jadidi, R., Chaikuad, A., Wearmouth, S. F., … & Morris, J. C. (2017). Development of potent, selective SRPK1 inhibitors as potential topical therapeutics for neovascular eye disease. ACS Chemical Biology, 12(3), 825-832. DOI: 10.1021/acschembio.6b01048

Bonomi, S., Gallo, S., Catillo, M., Pignataro, D., Biamonti, G., & Ghigna, C. (2013). Oncogenic alternative splicing switches: role in cancer progression and prospects for therapy. International Journal of Cell Biology, 2013:962038. DOI: 10.1155/2013/962038

Braeuer, R. R., Watson, I. R., Wu, C. J., Mobley, A. K., Kamiya, T., Shoshan, E., & Bar‐Eli, M. (2014). Why is melanoma so metastatic? Pigment Cell & Melanoma Research, 27(1), 19-36. DOI: 10.1111/pcmr.12172

David, C. J., & Manley, J. L. (2010). Alternative pre-mRNA splicing regulation in cancer: pathways and programs unhinged. Genes & Development, 24(21), 2343-2364. DOI: 10.1101/gad.1973010

da Silva, M. R., Moreira, G. A., Goncalves da Silva, R. A., de Almeida Alves Barbosa, É., Pais Siqueira, R., Teixera, R. R., ... & Bressan, G. C. (2015). Splicing regulators and their roles in cancer biology and therapy. BioMed Research International, 2015, Article ID 150514. DOI: 10.1155/2015/150514

Gammons, M. V., Lucas, R., Dean, R., Coupland, S. E., Oltean, S., & Bates, D. O. (2014). Targeting SRPK1 to control VEGF-mediated tumour angiogenesis in metastatic melanoma. British Journal of Cancer, 111(3), 477-485. DOI: 10.1038/bjc.2014.342

Gonçalves, V., Henriques, A., Pereira, J., Costa, A. N., Moyer, M. P., Moita, L. F., ... & Jordan, P. (2014). Phosphorylation of SRSF1 by SRPK1 regulates alternative splicing of tumor-related Rac1b in colorectal cells. RNA, 20(4), 474-482. DOI: 10.1261/rna.041376.113

Kim, Y. J., & Kim, H. S. (2012). Alternative splicing and its impact as a cancer diagnostic marker. Genomics & Informatics, 10(2), 74-80. DOI: 10.5808/GI.2012.10.2.74

Kozar, I., Margue, C., Rothengatter, S., Haan, C., & Kreis, S. (2019). Many ways to resistance: How melanoma cells evade targeted therapies. Biochimica et Biophysica Acta (BBA)-Reviews on Cancer, 1871(2), 313-322. DOI: https://doi.org/10.1016/j.bbcan.2019.02.002

Ladomery, M. (2013). Aberrant alternative splicing is another hallmark of cancer. International Journal of Cell Biology, 2013, 463786. DOI: 10.1155/2013/463786

Laikova, K. V., Oberemok, V. V., Krasnodubets, A. M., Gal’chinsky, N. V., Useinov, R. Z., Novikov, I. A., ... & Kubyshkin, A. V. (2019). Advances in the understanding of skin cancer: ultraviolet radiation, mutations, and antisense oligonucleotides as anticancer drugs. Molecules, 24(8), 1516-1543. DOI: 10.3390/molecules24081516

Liu, A. Y., Cai, Y., Mao, Y., Lin, Y., Zheng, H., Wu, T., ... & Ouyang, G. (2014). Twist2 promotes self-renewal of liver cancer stem-like cells by regulating CD24. Carcinogenesis, 35(3), 537-545. DOI: 10.1093/carcin/bgt364

Megahed, M., Schön, M., Selimovic, D., & Schön, M. P. (2002). Reliability of diagnosis of melanoma in situ. The Lancet, 359(9321), 1921-1922. DOI: 10.1016/s0140-6736(02)08741-x

Menaa, F. (2013). Latest approved therapies for metastatic melanoma: what comes next? Journal of skin cancer, 2013, 735282. DOI: 10.1155/2013/735282

Moon, H., Cho, S., Loh, T. J., Oh, H. K., Jang, H. N., Zhou, J., ... & Shen, H. (2014). SRSF2 promotes splicing and transcription of exon 11 included isoform in Ron proto-oncogene. Biochimica et Biophysica Acta (BBA)-Gene Regulatory Mechanisms, 1839(11), 1132-1140. DOI: 10.1016/j.bbagrm.2014.09.003

Moreira, G. A., de Almeida Lima, G. D., Siqueira, R. P., de Andrade Barros, M. V., Adjanohoun, A. L. M., Santos, V. C., ... & Bressan, G. C. (2018). Antimetastatic effect of the pharmacological inhibition of serine/arginine-rich protein kinases (SRPK) in murine melanoma. Toxicology and Applied Pharmacology, 356, 214-223. DOI: 10.1016/j.taap.2018.08.012

Nasti, T. H., & Timares, L. (2015). MC1R, eumelanin and pheomelanin: their role in determining the susceptibility to skin cancer. Photochemistry and Photobiology, 91(1), 188-200. DOI: 10.1111/php.12335

Pio, R., & Montuenga, L. M. (2009). Alternative splicing in lung cancer. Journal of Thoracic Oncology, 4(6), 674-678. DOI: https://doi.org/10.1097/JTO.0b013e3181a520dc

Siqueira, R. P., Barbosa, É. D. A. A., Polêto, M. D., Righetto, G. L., Seraphim, T. V., Salgado, R. L., ... & Bressan, G. C. (2015). Potential antileukemia effect and structural analyses of SRPK inhibition by N-(2-(piperidin-1-yl)-5-(trifluoromethyl) phenyl) isonicotinamide (SRPIN340). PLoS One, 10(8), e0134882. DOI: 10.1371/journal.pone.0134882

Suwanrungraung, K., & Kamsa-ard, S. (2007). Skin and melanoma. Cancer in Thailand. (VII), 2007-2009, Chapter II(12), 43-45. https://www.nci.go.th/th/File_download/Nci%20Cancer%20Registry/Cancer%20in%20thailand_VII.pdf

Tzelepis, K., De Braekeleer, E., Aspris, D., Barbieri, I., Vijayabaskar, M. S., Liu, W. H., ... & Vassiliou, G. S. (2018). SRPK1 maintains acute myeloid leukemia through effects on isoform usage of epigenetic regulators including BRD4. Nature Communications, 9(1), 1-13. DOI: 10.1038/s41467-018-07620-0

White, N., Knight, G. E., Butler, P. E., & Burnstock, G. (2009). An in vivo model of melanoma: treatment with ATP. Purinergic Signalling, 5(3), 327-333. DOI: https://doi.org/10.1007/s11302-009-9156-0

Xiping, Z., Qingshan, W., Shuai, Z., Hongjian, Y., & Xiaowen, D. (2017). A summary of relationships between alternative splicing and breast cancer. Oncotarget, 8(31), 51986-51993. DOI: 10.18632/oncotarget.17727

Yosudjai, J., Wongkham, S., Jirawatnotai, S., & Kaewkong, W. (2019). Aberrant mRNA splicing generates oncogenic RNA isoforms and contributes to the development and progression of Cholangiocarcinoma (Review). Biomedical Reports, 10(3), 147-155. DOI: https://doi.org/10.3892/br.2019.1188




How to Cite

Jesadagorn Siriwath, Natsupa Wiriyakulsit, Patcharee Klomkleang, Chaturong Inpad, Sittiruk Roytrakul, & Worasak Kaewkong. (2023). SPHINX31 suppresses splicing factor phosphorylation and inhibits melanoma cell growth and aggressiveness. Journal of Current Science and Technology, 11(3), 346–354. Retrieved from https://ph04.tci-thaijo.org/index.php/JCST/article/view/315



Research Article