An animal model of buccal mucosa cancer and cervical lymph node metastasis induced by U14 squamous cell carcinoma cells

Untold story of human cervical cancers: HPV-negative cervical cancer

Cervical cancer is the fourth most common malignancy in women worldwide. Although infection from human papillomavirus (HPV) has been the leading cause of cervical cancer, HPV-negative cervical cancer accounts for approximately 3-8% of all cases. Previous research studies on cervical cancer have focused on HPV-positive cervical cancer due to its prevalence, resulting in HPV-negative cervical cancer receiving considerably less attention. As a result, HPV-negative cervical cancer is poorly understood. Its etiology remains elusive mainly due to limitations in research methodology such as lack of defined markers and model systems. Moreover, false HPV negativity can arise from inaccurate diagnostic methods, which also hinders the progress of research on HPV-negative cervical cancer. Since HPV-negative cervical cancer is associated with worse clinical features, greater attention is required to understand HPV-negative carcinoma. In this review, we provide a summary of knowledge gaps and current limitations of HPV-negative cervical cancer research based on current clinical statistics. We also discuss future directions for understanding the pathogenesis of HPV-independent cervical cancer. [BMB Reports 2022; 55(9): 429-438].

Roles and mechanisms of miR-195-5p in human solid cancers

Cancer persists as a worldwide disease that contributes to high morbidity and mortality rates. As a class of non-coding RNA, microRNAs (miRNAs) are one kind of important regulators in cancer and frequently implicated in tumor development and progression. Emerging experiments have suggested that miRNA-195-5p (miR-195-5p) can regulate neoplastic processes in many pathways. For instance, miR-195-5p can not only regulate proliferation, migration and invasion of tumor cells but also promote tumor cell apoptosis. Furthermore, low expression of miR-195-5p could induce drug resistance. Our review focuses on the expression of miR-195-5p in various tumors and elucidates the related mechanisms of which miR-195-5p participates in tumor biology, as well as summarizes the roles of miR-195-5p in tumor progression. We believe that miR-195-5p might have potential utility as a novel diagnostic biomarker and therapeutic target for cancer.

Insight into the mechanism of aspartame-induced toxicity in male reproductive system following long-term consumption in mice model

Aspartame is one of the most common consumed artificial sweeteners utilized in many food products and beverages. It has been indicated that long-term consumption of aspartame leads to reproductive toxicity but its mechanism is not well-clear. In this study we investigated mechanism of aspartame-induced reproductive toxicity in male mice. For this purpose, 36 NMRI mature male mice received three doses of 40, 80, and 160 mg/kg body weight of aspartame, respectively per day by gavage for 90 days and also a control group was considered which received 0.5 mL of normal saline as the same route. The results revealed that long-term administration of aspartame at high doses significantly (P < .05) reduced gonadosomatic index, serum concentration of pituitary-testicular axis hormones (FSH, LH, and testosterone). It also decreased sperm parameters and total antioxidant capacity, antioxidant enzyme activities (superoxide dismutase, catalase, and glutathione peroxidase), while it caused increase in nitric oxide and malondialdehyde levels in testis tissue and sperm samples. Also, it decreased attenuated testicular histomorphometric indices (tubular differentiation index, spermiogenesis index, and repopulation index), and steroidogenic foci, while increased mRNA damages and apoptosis rate, downregulated antiapoptotic (Bcl-2) and upregulated proapoptotic (P53, BAX, and caspase-3) mediators respectively in testis. These findings indicated that consumption of aspartame for a long period results in male reproductive toxicity by decrease in serum concentration of pituitary-testis axis hormones and induction of oxidative stress and apoptosis in testis.

Early discovery of disseminated tumor cells during carcinogenesis in a 4NQO-induced mouse model of oral squamous cell carcinoma

OBJECTIVES

Heterogeneous cells appear in multiple organs during the same time period as the primary lesion of some tumors is clinically detected. These heterogeneous cells are also known as disseminated tumor cells (DTCs). However, the characteristics of DTCs that disseminate during oral carcinogenesis remain unclear.

MATERIALS AND METHODS

A mouse 4NQO model of lymph node metastasis in oral squamous cell carcinoma was established. Tissue samples of the tongue, bone marrow and submandibular lymph node were collected. Five stages (stage 0~stage IV) of carcinogenesis in each experimental animal were classified by two pathologists. After immunohistochemical staining of cytokeratin, the DTCs were isolated from bone marrow samples (stage II) by the laser capture microdissection (LCM) technique during oral carcinogenesis. Genomic amplification of bone marrow DTCs was performed, and homozygous deletion of the RB1CC1 gene was analyzed. After confirming the presence of disseminated tumor cells in stage II bone marrow samples, a comprehensive study among various stages of lymph node tissue was conducted using the same method.

RESULTS

DTCs that spread from the primary tumor were discovered in stage II bone marrow samples and in stage I, stage II and stage III submandibular lymph node samples through immunohistochemical staining. These spreading cells had different levels of homozygous exon deletion in the RB1CC1 and TP53 genes.

CONCLUSION

Early spreading of epithelial cells may occur during the carcinogenesis of oral cancer. DTCs of oral carcinoma may show different chromosome aberrations from matched primary tumor cells.

Histone Methyltransferase G9a Drives Chemotherapy Resistance by Regulating the Glutamate-Cysteine Ligase Catalytic Subunit in Head and Neck Squamous Cell Carcinoma

Transient chemotherapeutic response is a major obstacle to treating head and neck squamous cell carcinomas (HNSCC). Histone methyltransferase G9a has recently been shown to be abundantly expressed in HNSCC, and is required to maintain the malignant phenotype. In this study, we found that high G9a expression is significantly associated with poor chemotherapeutic response and disease-free survival in HNSCC patients. Similarly, G9a expression and enzymatic activity were elevated in cisplatin-resistant HNSCC cells. Genetic or pharmacologic inhibition of G9a sensitized the resistant cells to cisplatin, increasing cellular apoptosis. Mechanistic investigations indicated that G9a contributes to transcriptional activation of the glutamate-cysteine ligase catalytic subunit (GCLC), which results in upregulation of cellular glutathione (GSH) and drug resistance. In addition, we observed a significant positive correlation between G9a and GCLC expression in tumors of HNSCC patients. Taken together, our findings provide evidence that G9a protects HNSCC cells against chemotherapy by increasing the synthesis of GSH, and imply G9a as a promising target for overcoming cisplatin resistance in HNSCC. Mol Cancer Ther; 16(7); 1421-34. ©2017 AACR.

In vitro and in vivo anti-cancer activities of Kuding tea (Ilex kudingcha C.J. Tseng) against oral cancer

Kuding tea (Ilex kudingcha C.J. Tseng) is drunk widely in China. The in vitro anticancer effects of Kuding tea were evaluated in TCA8113 human tongue carcinoma cells using a 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide (MTT) assay. At a concentration of 200 μg/ml, Kuding tea exhibited an inhibitory effect of 75% in TCA8113 cells, which was higher than that observed at concentrations of 100 and 50 μg/ml (41 and 10% inhibition, respectively). Reverse transcription-polymerase chain reaction (RT-PCR) and western blot analyses of the apoptosis, inflammation and metastasis genes and proteins in Kuding tea-treated cancer cells were performed. Kuding tea significantly induced apoptosis in TCA8113 cancer cells (P<0.05) by upregulating Bax, caspase-3 and caspase-9 expression, and downregulating Bcl-2 expression. Expression of the NF-κB, iNOS and COX-2 genes that are associated with inflammation was significantly downregulated by Kuding tea, which demonstrated its anti-inflammatory properties. Kuding tea also exerted an anti-metastatic effect on cancer cells. This was demonstrated by the decreased expression of matrix metalloproteases (MMPs) and the increased expression of tissue inhibitors of metalloproteinases (TIMPs), and confirmed by the inhibition of the metastasis of U14 squamous cell carcinoma cells in imprinting control region (ICR) mice. The ICR mouse buccal mucosa cancer model was established by injecting the mice with U14 cells. Following injection, the wound at the injection site was topically treated with Kuding tea. It was observed that the tumor volumes for the group treated with Kuding tea were smaller than those from the control mice. Analysis of the sections of buccal mucosa cancer tissue demonstrated that the buccal mucosa cancer degrees of the Kuding tea-treated mice were weaker than that in the control mice. Similar results were observed in the lesion sections of the cervical lymph nodes. Based on these results, Kuding tea exhibited successful in vitro anticancer effects in TCA8113 cells and in vivo buccal mucosa cancer preventive activity.