Cervical cancer (CVC) ranks among the most prevalent malignancies affecting women[1]. Nowadays, an increasing number of younger individuals are being diagnosed with CVC, highlighting its growing incidence. It is now understood that CVC progression spans a prolonged period, typically evolving from precancerous states to fully invasive malignancy over 5–10 years[2]. Extensive research underscores the significant association between human papillomavirus (HPV) infection and CVC, with over 99% of patients demonstrating concurrent HPV infection[3]. These proteins exert their influence primarily by overriding the host cell's negative growth control mechanisms and inducing genomic instability. As biomarkers within CVC cells, E6 and E7 are pivotal in driving cancer progression[4]. Consequently, the inhibition of E6 and E7 protein expression, coupled with the identification of novel target proteins, holds substantial promise for advancing CVC treatment strategies.
Cinnamaldehyde (CA) is widely acknowledged as the principal constituent of the volatile oil derived from Cinnamomum genus[5]. Distinguished by its affordability, potent pharmacological activity, and low toxicity profile[6], recent investigations have unveiled its diverse therapeutic effects encompassing anti-inflammatory[7], anti-diabetic[8], anti-obesity[9], anti-bacterial[10] and neuroprotective[11] functions. Furthermore, CA has demonstrated efficacy against a spectrum of tumors[12], including leukemia[13], hepatocellular carcinoma[14], glioma[15], melanoma[16], lung cancer[17], and prostate cancer[18]. Despite reports highlighting CA's inhibitory potential against CVC cell growth[19], the precise underlying mechanisms and target proteins remain poorly understood.
Ribosomal protein16 (RPS16) constitutes a pivotal component of the 40S ribosomal subunit, localized within the cytoplasm and serving as a quintessential ribosomal coding protein involved in gene replication, transcription, and translation regulation. Given that the nucleolus is the central hub for ribosome biogenesis, an energetically resource-intensive cellular procedure, any disturbances to ribosome biogenesis lead to ribosomal stress, commonly referred to as nucleolar stress[20]. The association between the DNA damage response and the nucleolus has revealed that the nucleolus functions as a detector of stress signals within cells by stabilizing p53 through interactions involving ribosomal protein (RP)-MDM2/HDM2. This interaction subsequently leads to the initiation of cell cycle arrest or apoptosis[21]. Studies have shown that upregulation of the RPS16 gene significantly correlated with prostate cancer progression. Increased RPS16 protein expression has been linked to augmented proliferation and invasiveness of prostate cancer cells[22]. RPS16 protein's participation in tumor progression has been unveiled in various tumors, regulated by upstream microRNA influences[23]. Unfortunately, the role of RPS16 in cervical cancer remains unclear.
This study demonstrated CA's capacity to induce cell cycle arrest and apoptosis, alongside its capability to inhibit both expression levels and signaling functions of E6 and E7, highlighting CA's anti-CVC potential both in vitro and in vivo. Additionally, employing an alkynyl-CA probe (AL-CA), RPS16 was identified as CA's target within CVC. Covalent binding between CA and RPS16 disrupted the latter's stability; accordingly, RPS16 could be targeted, inhibiting E6 and E7 expression. Taken together, these findings offer novel insights into potential strategies for advancing CVC treatment.