Downregulation of KIF2C and TEKT2 is associated with male infertility and testicular carcinoma

Sperm plasma membrane ion transporters and male fertility potential: A perspective under the prism of cryopreservation

Intracellular calcium homeostasis plays a crucial role in spermatozoa by regulating physiological functions associated with sperm quality and male fertility potential. Intracellular calcium fine balance in the sperm cytoplasm is strictly dependent on sperm surface channels including the CatSper channel. CatSpers' role is to ensure the influx of extracellular calcium, while intracellular pH alkalinization serves as a stimulus for the activation of several channels, including CatSper. Overall, the generation of intracellular calcium spikes through CatSper is essential for fertilization-related processes, such as sperm hyperactivation, acrosome reaction, egg chemotaxis, and zona pellucida penetration. Multiple lines of evidence suggest that disruption in the close interaction among ions, pH, and CatSper could impair male fertility potential. In contemporary times, the growing reliance on Medically Assisted Reproduction procedures underscores the impact of cryopreservation on gametes. In fact, a large body of literature raises concerns about the cryo-damages provoked by the freeze-thawing processes, that can affect the plasma membrane integrity, thus the structure of pivotal ion channels, and the fine regulation of both intracellular calcium and pH. This review aims to provide an overview of the importance of the CatSper channel in sperm quality and further fertilization potential. Additionally, it addresses the emerging issue of cryopreservation's impact on the functionality of this sperm channel.

KIF2C: An important factor involved in signaling pathways, immune infiltration, and DNA damage repair in tumorigenesis

BACKGROUNDS

Poorly regulated mitosis and chromosomal instability are common characteristics in malignant tumor cells. Kinesin family member 2 C (KIF2C), also known as mitotic centromere-associated kinesin (MCAK) is an essential component during mitotic regulation. In recent years, KIF2C was shown to be dysregulated in several tumors and was involved in many aspects of tumor self-regulation. Research on KIF2C may be a new direction and target for anti-tumor therapy.

OBJECT

The article aims at reviewing current literatures and summarizing the research status of KIF2C in malignant tumors as well as the oncogenic signaling pathways associated with KIF2C and its role in immune infiltration.

RESULT

In this review, we summarize the KIF2C mechanisms and signaling pathways in different malignant tumors, and briefly describe its involvement in pathways related to classical chemotherapeutic drug resistance, such as MEK/ERK, mTOR, Wnt/β-catenin, P53 and TGF-β1/Smad pathways. KIF2C upregulation was shown to promote tumor cell migration, invasion, chemotherapy resistance and inhibit DNA damage repair. It was also highly correlated with microRNAs, and CD4 +T cell and CD8 +T cell tumor immune infiltration.

CONCLUSION

This review shows that KIF2C may function as a new anticancer drug target with great potential for malignant tumor treatment and the mitigation of chemotherapy resistance.

Targeted mutation and inactivation of the kinesin light chain 3 protein-encoding gene have no impact on mouse fertility†

The kinesin light chain 3 protein (KLC3) is the only member of the kinesin light chain protein family that was identified in post-meiotic mouse male germ cells. It plays a role in the formation of the sperm midpiece through its association with both spermatid mitochondria and outer dense fibers (ODF). Previous studies showed a significant correlation between its expression level and sperm motility and quantitative semen parameters in humans, while the overexpression of a KLC3-mutant protein unable to bind ODF also affected the same traits in mice. To further assess the role of KLC3 in fertility, we used CRISPR/Cas9 genome editing in mice and investigated the phenotypes induced by the invalidation of the gene or of a functional domain of the protein. Both approaches gave similar results, i.e. no detectable change in male or female fertility. Testis histology, litter size and sperm count were not altered. Apart from the line-dependent alterations of Klc3 mRNA levels, testicular transcriptome analysis did not reveal any other changes in the genes tested. Western analysis supported the absence of KLC3 in the gonads of males homozygous for the inactivating mutation and a strong decrease in expression in males homozygous for the allele lacking one out of the five tetratricopeptide repeats. Overall, these observations raise questions about the supposedly critical role of this kinesin in reproduction, at least in mice where its gene mutation or inactivation did not translate into fertility impairment.

Lymph node metastasis-related gene signature shows good performance in predicting prognosis and immune infiltration in cervical cancer

Aims

This study aimed to construct a lymph node metastasis-related gene signature to predict prognosis and immune infiltration in patients with cervical cancer.

Methods

Clinical and RNA sequencing data of 193 patients with cervical cancer, which were divided into lymph node metastasis (N1) and non-lymph node metastasis (N0) groups, were acquired from TCGA. Differentially expressed genes (DEGs) between the N1 and N0 groups were detected, and protein-protein interaction combined with LASSO analysis was conducted to further screen lymph node metastasis-related genes. Univariate and multivariate Cox regression analyses were performed to establish a predictive signature. The genetic features, potential biological behavior, and immune infiltration characteristics of the predictive signature were explored. Furthermore, the sensitivity of patients to chemotherapy drugs was estimated based on the predictive signature and the expression of TEKT2 and RPGR was investigated in the cervical cancer tissue samples.

Results

A total of 271 lymph node metastasis-related DEGs, including 100 upregulated and 171 downregulated genes, were identified. Two genes, TEKT2 and RPGR, were associated with lymph node metastasis and prognosis in cervical cancer, and were used to construct a lymph node metastasis-related predictive signature. Based on the predictive signature, patients with cervical cancer were divided into high- and low-risk groups. The high-risk group, characterized by a higher tumor mutation burden and somatic mutation rate, indicated a poor overall survival. The activation of immune infiltration and increased expression of checkpoint genes were observed in the high-risk group, indicating that they might benefit from immunotherapy. Cytarabine, FH535, and procaspase-activating compound-1 were estimated as reasonable chemotherapy options for patients in the high-risk group, whereas two taxanes and five tyrosine kinase inhibitors, including etoposide and vinorelbine, had therapeutic significance for patients in the low-risk group. The expression of TEKT2 and RPGR was significantly downregulated in cervical cancer tissues, especially in metastatic lymph node tissues.

Discussion

The lymph node metastasis-related predictive signature based on TEKT2 and RPGR showed good performance in predicting the survival outcomes of patients with cervical cancer. The risk score of the predictive signature was related to genetic variation and immune infiltration, which could guide immunotherapy and chemotherapy strategies.

MAEL gene contributes to bovine testicular development through the m5C-mediated splicing

Knowledge of RNA molecules regulating testicular development and spermatogenesis in bulls is essential for elite bull selection and an ideal breeding program. Herein, we performed direct RNA sequencing (DRS) to explore the functional characterization of RNA molecules produced in the testicles of 9 healthy Simmental bulls at three testicular development stages (prepuberty, puberty, and postpuberty). We identified 5,043 differentially expressed genes associated with testicular weight. These genes exhibited more alternative splicing at sexual maturity, particularly alternative 3' (A3) and 5' (A5) splice sites usage and exon skipping (SE). The expression of hub genes in testicular developmental stages was also affected by both m6A and m5C RNA modifications. We found m5C-mediated splicing events significantly (p < 0.05) increased MAEL gene expression at the isoform level, likely promoting spermatogenesis. Our findings highlight the complexity of RNA processing and expression as well as the regulation of transcripts involved in testicular development and spermatogenesis.

Effects of epidemiological risk factors on prognosis in testicular cancer

PURPOSE

Testicular cancer is frequently seen, especially in young males, and constitutes 1% of all male cancers. Family history, testicular dysgenesis syndrome, and the presence of tumour in the contralateral testis are each well-defined epidemiological risk factors. The aim of the current study was to determine the distribution of these risk factors according to tumour stage and to evaluate the effects on progression.

MATERIALS AND METHODS

A total of 71 patients diagnosed with testicular cancer in our clinic between January 2018 and December 2021 were classified according to tumour stage (Group 1: Early, n = 29; Group 2: Advanced, n = 42). The presence of risk factors, and demographic and pathological data were recorded.

RESULTS

No significant difference was determined between the groups in respect of age, comorbidities, and tumour type (p > 0.05). There was no difference between Group 1 and Group 2 in terms of median follow-up time [15.5 (17.5), 16.5(26.5) months, respectively, p = 0.4]. Epidemiological risk factors were seen more in Group 2 than in Group 1 (p = 0.03). Progression-free survival was determined to be shorter in patients with risk factors compared to those without (7.95 ± 1.3 vs. 29.4 ± 2.06 months, p < 0.001, respectively). Family history and testicular dysgenesis syndrome were determined to be independent risk factors for progression [HR:0.046 (0.004-0.485); HR:0.101 (0.03-0.347), p < 0.05, respectively].

CONCLUSIONS

More advanced-stage tumours are seen in patients with testicular cancer when epidemiological risk factors are also present. Of these risk factors, family history and testicular dysgenesis syndrome have a negative effect on progression.

Aberrant Gene Expression Profiling in Men With Sertoli Cell-Only Syndrome

Sertoli cell-only syndrome (SCOS) is the most severe and common pathological type of non-obstructive azoospermia. The etiology of SCOS remains largely unknown to date despite a handful of studies reported in this area. According to the gene expression of testicular tissue samples in six datasets from the Gene Expression Omnibus, we detected 1441 differentially expressed genes (DEGs) between SCOS and obstructive azoospermia (OA) testicular tissue samples. Enriched GO terms and KEGG pathways for the downregulated genes included various terms and pathways related to cell cycle and reproduction, while the enrichment for the upregulated genes yielded many inflammation-related terms and pathways. In accordance with the protein-protein interaction (PPI) network, all genes in the most critical module belonged to the downregulated DEGs, and we obtained nine hub genes, including CCNB1, AURKA, CCNA2, BIRC5, TYMS, UBE2C, CDC20, TOP2A, and OIP5. Among these hub genes, six were also found in the most significant SCOS-specific module obtained from consensus module analysis. In addition, most of SCOS-specific modules did not have a consensus counterpart. Based on the downregulated genes, transcription factors (TFs) and kinases within the upstream regulatory network were predicted. Then, we compared the difference in infiltrating levels of immune cells between OA and SCOS samples and found a significantly higher degree of infiltration for most immune cells in SCOS than OA samples. Moreover, CD56bright natural killer cell was significantly associated with six hub genes. Enriched hallmark pathways in SCOS had remarkably more upregulated pathways than the downregulated ones. Collectively, we detected DEGs, significant modules, hub genes, upstream TFs and kinases, enriched downstream pathways, and infiltrated immune cells that might be specifically implicated in the pathogenesis of SCOS. These findings provide new insights into the pathogenesis of SCOS and fuel future advances in its theranostics.

Kinesins in Mammalian Spermatogenesis and Germ Cell Transport

In mammalian testes, the apical cytoplasm of each Sertoli cell holds up to several dozens of germ cells, especially spermatids that are transported up and down the seminiferous epithelium. The blood-testis barrier (BTB) established by neighboring Sertoli cells in the basal compartment restructures on a regular basis to allow preleptotene/leptotene spermatocytes to pass through. The timely transfer of germ cells and other cellular organelles such as residual bodies, phagosomes, and lysosomes across the epithelium to facilitate spermatogenesis is important and requires the microtubule-based cytoskeleton in Sertoli cells. Kinesins, a superfamily of the microtubule-dependent motor proteins, are abundantly and preferentially expressed in the testis, but their functions are poorly understood. This review summarizes recent findings on kinesins in mammalian spermatogenesis, highlighting their potential role in germ cell traversing through the BTB and the remodeling of Sertoli cell-spermatid junctions to advance spermatid transport. The possibility of kinesins acting as a mediator and/or synchronizer for cell cycle progression, germ cell transit, and junctional rearrangement and turnover is also discussed. We mostly cover findings in rodents, but we also make special remarks regarding humans. We anticipate that this information will provide a framework for future research in the field.