Expression of hypoxia-induced factor-1 alpha in early-stage and in metastatic oral squamous cell carcinoma

Exogenous BMI1 expression aggravates oral squamous cell carcinomas in tongue epithelia

Oral squamous cell carcinoma (OSCC) is characterized by aggressiveness and a poor prognosis, in part because most patients are diagnosed during the later stages of the disease. B cell-specific Moloney murine leukemia virus integration site 1 (BMI1), part of polycomb repressive complex 1 (PRC1), is a key transcription factor overexpressed in OSCC. Although increased BMI1 has been linked to tumor formation in mouse models of the disease, the molecular mechanisms have not been elucidated. Here we used a transgenic mouse line (KrTB) that selectively overexpresses BMI1 in the tongue basal epithelial stem cells (SCs) to delineate BMI1 actions during oral tumorigenesis. By tumor pathological classification after 4-nitroquinoline 1-oxide (4-NQO)-induced carcinogenesis we detected more severe tumors in mice with ectopic BMI1 expression. Genome-wide transcriptomics indicated that mRNAs associated with human OSCC, including SOX9, HIF1A, MMP9, INHBB, and MYOF, were further increased by ectopic BMI1 expression in murine tongue epithelia. mRNAs encoding multiple metabolic targets, such as SLC2A1 (GLUT1), PKM, LDHA, and HK2, were also increased upon BMI1 overexpression in 4-NQO-treated tongue epithelia. Furthermore, we detected BMI1, SOX9, and GLUT1 proteins in the infiltrating cells of invasion fronts identified by markers of invasive SCCs. Finally, metabolomic data show that BMI1 overexpression in tongue epithelia promotes glycolysis during 4-NQO-induced carcinogenesis. Thus, our data demonstrate that BMI1 causes OSCC cells to alter cell metabolism, as changes in many of these transcripts are linked to increased glycolysis and metabolic reprograming that occurs during carcinogenesis.

Correlation of microscopic tumor extension with tumor microenvironment in esophageal cancer patients

OBJECTIVE

In the era of image-guided adaptive radiotherapy, definition of the clinical target volume (CTV) is a challenge in various solid tumors, including esophageal cancer (EC). Many tumor microenvironmental factors, e.g., tumor cell proliferation or cancer stem cells, are hypothesized to be involved in microscopic tumor extension (MTE). Therefore, this study assessed the expression of FAK, ILK, CD44, HIF-1α, and Ki67 in EC patients after neoadjuvant radiochemotherapy followed by tumor resection (NRCHT+R) and correlated these markers with the MTE.

METHODS

Formalin-fixed paraffin-embedded tumor resection specimens of ten EC patients were analyzed using multiplex immunofluorescence staining. Since gold fiducial markers had been endoscopically implanted at the proximal and distal tumor borders prior to NRCHT+R, correlation of the markers with the MTE was feasible.

RESULTS

In tumor resection specimens of EC patients, the overall percentages of FAK+, CD44+, HIF-1α+, and Ki67+ cells were higher in tumor nests than in the tumor stroma, with the outcome for Ki67+ cells reaching statistical significance (p < 0.001). Conversely, expression of ILK+ cells was higher in tumor stroma, albeit not statistically significantly. In three patients, MTE beyond the fiducial markers was found, reaching up to 31 mm.

CONCLUSION

Our findings indicate that the overall expression of FAK, HIF-1α, Ki67, and CD44 was higher in tumor nests, whereas that of ILK was higher in tumor stroma. Differences in the TME between patients with residual tumor cells in the original CTV compared to those without were not found. Thus, there is insufficient evidence that the TME influences the required CTV margin on an individual patient basis.

TRIAL REGISTRATION NUMBER AND DATE

BO-EK-148042017 and BO-EK-177042022 on 20.06.2022, DRKS00011886, https://drks.de/search/de/trial/DRKS00011886 .

Hypoxia disrupt tight junctions and promote metastasis of oral squamous cell carcinoma via loss of par3

BACKGROUND

Oral squamous cell carcinoma (OSCC) is a highly malignant tumor that is frequently associated with lymph node metastasis, resulting in poor prognosis and survival in patients. In the tumor microenvironment, hypoxia plays an important role in regulating cellular responses such as progressive and rapid growth and metastasis. In these processes, tumor cells autonomously undergo diverse transitions and acquire functions. However, hypoxia-induced transition of OSCC and the involvement of hypoxia in OSCC metastasis remain unclear. Therefore, in this study, we aimed to elucidate the mechanism of hypoxia-induced OSCC metastasis and particularly, its impact on tight junctions (TJs).

METHODS

The expression of hypoxia-inducible factor 1-alpha (HIF-1α) was detected in tumor tissues and adjacent normal tissues from 29 patients with OSCC using reverse transcription quantitative real-time polymerase chain reaction (qRT-PCR), western blotting, and immunohistochemistry (IHC). The migration and invasion abilities of OSCC cell lines treated with small interfering (si)RNA targeting HIF-1α or cultured in hypoxic conditions were analyzed using Transwell assays. The effect of HIF-1α expression on in vivo tumor metastasis of OSCC cells was evaluated using lung metastasis model.

RESULTS

HIF-1α was overexpressed in patients with OSCC. OSCC metastasis was correlated with HIF-1α expression in OSCC tissues. Hypoxia increased the migration and invasion abilities of OSCC cell lines by regulating the expression and localization of partitioning-defective protein 3 (Par3) and TJs. Furthermore, HIF-1α silencing effectively decreased the invasion and migration abilities of OSCC cell lines and restored TJ expression and localization via Par3. The expression of HIF-1α was positively regulated the OSCC metastasis in vivo.

CONCLUSIONS

Hypoxia promotes OSCC metastasis by regulating the expression and localization of Par3 and TJ proteins. HIF-1α positively correlates to OSCC metastasis. Lastly, HIF-1α expression could regulate the expression of Par3 and TJs in OSCC. This finding may aid in elucidating the molecular mechanisms of OSCC metastasis and progression and developing new diagnostic and therapeutic approaches for OSCC metastasis.

Combined effects of hyperthermia and chemotherapy on the regulate autophagy of oral squamous cell carcinoma cells under a hypoxic microenvironment

Autophagy has a complex dual role in tumor survival or cell death owning to that is an evolutionarily conserved catabolic mechanism and provides the cells with a sustainable source of biomolecules and energy for the maintenance of homeostasis under stressful conditions such as tumor microenvironment. Hyperthermia is a rapidly growing field in cancer therapy and many advances have been made in understanding and applying the mechanisms of hyperthermia. The shallow oral and maxillofacial position and its abundant blood supply are favorable for the use of hyperthermia. However, the relationship between hyperthermia and autophagy has not been examined of oral squamous cell carcinoma (OSCC) in the tumor hypoxia microenvironment. Here, the expression level of autophagy relative genes is examined to explore autophagy effect on the responses of hyperthermia, hypoxia, and innutrition tumor microenvironment. It is founded that hyperthermia and hypoxia cause autophagy in starvation conditions; further, in hypoxia and innutrition tumor microenvironment, hyperthermia combines YC-1 and 3-MA could inhibit HIF-1α/BNIP3/Beclin1 signal pathway and decrease the secretion of HMGB1; moreover, the cell apoptosis rate increases with an inhibited of cell migration capacity. Thus, the present study demonstrated that combined use of YC-1 and 3-MA might increase the death of tumor cells in physiological and hyperthermic conditions, which could be relevant with the inhibition of autophagy in OSCC tumor cells under hypoxia microenvironment in vitro, which offers new insight into the therapy of OSCC and its application in treating others study carcinomas.

Current Understanding of the HIF-1-Dependent Metabolism in Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is the 10th most frequent human malignancy and is thus a global burden. Despite some progress in diagnosis and therapy, patients' overall survival rate, between 40 and 55%, has stagnated over the last four decades. Since the tumor node metastasis (TNM) system is not precise enough to predict the disease outcome, additive factors for diagnosis, prognosis, prediction and therapy resistance are urgently needed for OSCC. One promising candidate is the hypoxia inducible factor-1 (HIF-1), which functions as an early regulator of tumor aggressiveness and is a key promoter of energy adaptation. Other parameters comprise the composition of the tumor microenvironment, which determines the availability of nutrients and oxygen. In our opinion, these general processes are linked in the pathogenesis of OSCC. Based on this assumption, the review will summarize the major features of the HIF system-induced activities, its target proteins and related pathways of nutrient utilization and metabolism that are essential for the initiation, progression and therapeutic stratification of OSCC.

Hypoxia regulates the differentiation and anti-tumor effector functions of γδT cells in oral cancer

Hypoxia within the tumor microenvironment (TME) is a key factor contributing to immunosuppression in tumors, co-relating with poor treatment outcome and decreased overall survival in advanced oral cancer (OC) patients. Vδ2 is a dominant subset of gamma delta T cells (γδT cells) present in the peripheral blood which exhibits potent anti-tumor cytotoxicity and is evolving as a key player of anti-cancer cellular therapy. However, the fate of γδT cells in hypoxic oral tumors remains elusive. In the present study, we compared the effect of hypoxia (1% O₂ ) and normoxia (21% O₂ ) on the expansion, proliferation, activation status, cytokine secretion and cytotoxicity of γδT cells isolated from OC patients and healthy individuals. Hypoxia-exposed γδT cells exhibited reduced cytotoxicity against oral tumor cells. Our data demonstrated that hypoxia reduces the calcium efflux and the expression of degranulation marker CD107a in γδT cells, which explains the decreased anti-tumor cytotoxicity of γδT cells observed under hypoxia. Hypoxia-exposed γδT cells differentiated to γδT17 [γδ T cells that produce interleukin (IL)-17] cells, which corroborated our observations of increased γδT17 cells observed in the oral tumors. Co-culture of γδT cells with CD8 T cells in the presence of hypoxia showed that programmed cell death ligand 1 (PD-L1)^high γδT cells brought about apoptosis of programmed cell death 1 (PD-1)^high CD8 T cells which could be significantly reversed upon blocking PD-1. Thus, future immunotherapeutic treatment modality for oral cancer may use a combined approach of blocking the PD-1/PD-L1 signaling and targeting hypoxia-inducible factor 1α, which may help in reversing hypoxia-induced immunosuppression.

HIF-1α Promotes the Metastasis of Esophageal Squamous Cell Carcinoma by Targeting SP1

Background: In microenvironment of malignant tumors, Hypoxia-Inducible Factors (HIF), most importantly HIF-1α, play an important role in regulation of adaptive biological response to hypoxia, promoting angiogenesis and metastasis. However, the underlying mechanism that HIF-1α regulates metastasis needs to be further clarified. Methods: The expressions of HIF-1α and SP1 were detected in 182 samples of esophageal squamous cell carcinoma (ESCC) and adjacent normal tissues by immunohistochemistry (IHC), and the correlation between the expression levels of HIF-1α and SP1 was analyzed. The expression of HIF-1α in ESCC cell lines TE1 and KYSE30 was then detected using qRT-PCR and western blot. The potential binding sites of HIF-1α on the SP1 promoter were analyzed using UCSC and JASPAR databases, verified by chromosomal immunoprecipitation (ChIP) assay and qRT-PCR. The effects of HIF-1α and SP1 on ESCC cell migration and invasion were then tested with Transwell and Matrigel experiments. Results: The expression of HIF-1α in cancer tissues is higher than adjacent normal tissues, and is correlated with metastasis, recurrence and poor prognosis. Upon silencing HIF-1α by siRNA, the invasion and migration ability of ESCC cells were significantly inhibited, which could be restored by the overexpression of SP1. Hypoxic conditions significantly increased the expression of HIF-1α and SP1 at both protein and mRNA levels in ESCC cells. HIF-1α enhanced SP1 transcription through binding to the promoter region. The expression of protein and mRNA levels of SP1 was decreased by silencing HIF-1α in cells. In contrast, overexpression of HIF-1α significantly increased the mRNA and protein levels of SP1. The expression of SP1 in ESCC was positively correlated with the protein expression of HIF-1α and poor prognosis. Conclusion: The results of our study indicate that HIF-1α promotes metastasis of ESCC by targeting SP1 in a hypoxic microenvironment. Further study on this mechanism may elucidate the possibility of HIF-1α and SP1 as new targets for the treatment of ESCC.

Glucose metabolism changes during the development and progression of oral tongue squamous cell carcinomas

Previous studies have revealed several genes involved in the carcinogenesis of oral cancer. However, the detailed mechanisms underlying this process are poorly understood. Previously, we established a database cataloging the transcriptional progression profile of oral carcinogenesis and identified several candidate genes with continuously increasing or decreasing expression, which specifically promote the transition of oral premalignant lesions to invasive carcinomas. In this study, using our microarray database, we attempted to determine significant genes that may contribute to metabolic alterations during oral carcinogenesis. After performing a literature survey, we focused on 15 candidate genes associated with glucose metabolism changes, particularly the tri-carboxylic acid cycle, and investigated the mRNA-expression status of these genes with our database. Only the solute carrier family 2 member 1 gene (also known as GLUT1), showed significantly increased mRNA expression during oral tumorigenesis. Immunohistochemical analysis confirmed that GLUT1 protein expression significantly increased during oral carcinogenesis. In addition, tumors with high expression of this protein significantly correlated with nodal status (P=0.002). Kaplan-Meier survival curves clearly demonstrated the adverse impact of high GLUT1 protein expression on disease-free survival (P=0.004). GLUT1 mRNA and protein expression increased in the order of normal mucosal tissues, epithelial dysplastic lesions and invasive carcinomas. Therefore, metabolic alterations, especially in glucose metabolism, occurred at the very early stage of development of oral malignancies. In addition, GLUT1 played a significant role in oral cancer, acquiring a malignant phenotype.

Participation of hypoxia-inducible factor-1α and lymphangiogenesis in metastatic and non-metastatic lower lip squamous cell carcinoma

This study evaluated the lymphatic density and HIF-1α immunoexpression in lower lip squamous cell carcinoma (LLSCC) and their correlation with clinicopathological (nodal metastasis, clinical stage, histological grade, recurrence and disease outcome) and survival parameters in 20 metastatic and 20 non-metastatic LLSCCs. Lymphatic density was established by counting microvessels (D2-40⁺) at the tumor core (intratumoral lymphatic density, ILD) and at the invasive front (peritumoral lymphatic density, PLD) and percentages of immunopositive cells for HIF-1α were established. No statistically significant differences in lymphatic densities in relation to clinicopathological parameters were observed (P > 0.05). All cases exhibited nuclear and cytoplasmic HIF-1α immunoexpression, with relatively high percentages of positivity, but this expression was not statistically different in relation to clinicopathological variables (P > 0.05). Positive correlations were observed between ILD and PLD (P = 0.002), and between nuclear HIF-1α immunoexpression at the tumor core and ILD (P = 0.001). The results suggest ILD and PLD are not directly related to the development of lymph node metastasis in LLSCC. The striking expression of HIF-1α suggests the involvement of this protein in the etiopathogenesis of LLSCCs, possibly stimulating lymphangiogenesis at the tumor core. However, this protein does not seem to exert a determining influence on the biological aggressiveness of these tumors.

Increased expression of hypoxia-inducible factor-1 alpha and its impact on transcriptional changes and prognosis in malignant tumours of the ocular adnexa

PURPOSE

To investigate the expression profile of the hypoxia-inducible transcription factor-1α (HIF-1α) and its downstream targets in malignancies of the ocular adnexa and to determine its relevance as a prognostic factor for clinical outcome.

METHODS

We included 49 subjects with malignant tumours (25 squamous cell carcinomas (SCC), 15 non-Hodgkin lymphomas, 9 melanomas) and 30 patients with benign tumours of the ocular adnexa (13 papillomas, 7 reactive lymphoid hyperplasias (RLHs) and 10 nevi) as controls. We quantified HIF-1α protein expression by immunohistochemistry and assessed the association between HIF-1α and clinical outcome via Kaplan-Meier analysis. Furthermore, we assessed the expression of HIF-1α downstream factors by transcriptional sequencing using the MACE (massive analysis of cDNA ends) technology.

RESULTS

SCCs revealed a strong HIF-1α expression in 61% of tumour cells in comparison with only 22% in papillomas (p < 0.0001). In contrast, malignant melanomas and lymphomas revealed a similar HIF-1α expression compared with nevi and RLHs. Transcriptional sequencing and Gene Ontology Cluster analysis demonstrated 37 hypoxia-associated factors, including HIF-1α, VEGF, SFRP1 and LOXL2 that are significantly increased in SCC and may contribute to tumour proliferation, angiogenesis, and metastasis. Association analysis between HIF-1α immunoreactivity and clinical outcome revealed a trend towards an unfavourable prognosis in malignant tumours with increased HIF-1α expression.

CONCLUSIONS

HIF-1α protein is increased in malignant tumours of the ocular adnexa, which is associated with an increase in multiple HIF-1α-downstream factors and a trend towards an unfavourable clinical outcome.