Antisense oligonucleotides and all-trans retinoic acid have a synergistic anti-tumor effect on oral squamous cell carcinoma

Effect of IL-27, Teriflunomide and Retinoic Acid and Their Combinations on CD4+ T Regulatory T Cells-An In Vitro Study

The principal goal of the study was to verify the concept of pharmacological induction of Foxp3⁺CD25⁺CD4⁺ T regulatory (Treg) cells which will additionally be characterized by a highly suppressive phenotype, i.e., by extensive CD25 and CD39 expression and IL-10 and TGF-β production. Stimulated and unstimulated murine lymphocytes were exposed to IL-27, teriflunomide (TER), and all trans retinoic acid (ATRA) alone and to their combinations. The study demonstrated that: (a) IL-27 alone induced CD39 expression on Treg cells and the generation of Tr1 cells; (b) TER alone induced Foxp3-expressing CD4⁺ T cells and up-regulated density of CD25 on these cells; TER also induced the ability of Treg cells to TGF-β production; (c) ATRA alone induced CD39 expression on Treg cells. The experiments revealed a strong superadditive effect between IL-27 and ATRA with respect to increasing CD39 expression on Treg cells. Moreover, IL-27 and ATRA in combination, but not alone, induced the ability of Treg cells to IL-10 production. However, the combination of IL-27, TER, and ATRA did not induce the generation of Treg cell subset with all described above features. This was due to the fact that TER abolished all listed above desired effects induced by IL-27 alone, ATRA alone, and their combination. IL-27 alone, ATRA alone, and their combination affected TER-induced effects to a lesser extent. Therefore, it can be concluded that in the aspect of pharmacological induction of Treg cells with a highly suppressive phenotype, the triple combination treatment with TER, IL-27, and ATRA does not provide any benefits over TER alone or dual combination including IL-27 and ATRA.

Development of a multifunctional gold nanoplatform for combined chemo-photothermal therapy against oral cancer

Aim: To design and fabricate a multifunctional drug-delivery nanoplatform for oral cancer therapy. Materials & methods: Polyethylene glycol-stabilized, PDPN antibody (PDPN Ab)- and doxorubicin (DOX)-conjugated gold nanoparticles (AuNPs) were prepared and evaluated for their cytotoxicity and antitumor efficacy in both chemotherapy and photothermal therapy. Results: The obtained (PDPN Ab)-AuNP-DOX system presents low toxicity, a high drug loading capacity and cellular uptake efficiency. Both in vitro and in vivo experiments demonstrate that (PDPN Ab)-AuNP-DOX has enhanced antitumor efficacy. Treatment with (PDPN Ab)-AuNP-DOX combined with laser irradiation exhibits superior antitumor effects. Conclusion: This (PDPN Ab)-AuNP-DOX system may be used as a versatile drug-delivery nanoplatform for targeted and combined chemo-photothermal therapy against oral cancer.

All-trans retinoic acid induces anti-tumor effects via STAT3 signaling inhibition in oral squamous cell carcinoma and oral dysplasia

BACKGROUND

Oral squamous cell carcinoma (OSCC), which may arise from oral dysplasia, is one of the most prevalent cancers around the world. In recent years, all-trans retinoic acid (ATRA) has shown great potential in cancer treatment. However, the molecular mechanism for the anti-tumor effects of ATRA remains unclear.

MATERIALS AND METHODS

After treated with ATRA, inhibition of cell proliferation of OSCC and oral dysplasia cell lines, CAL27 and DOK, respectively, was analyzed by a Cell Counting Kit-8 (CCK8) assay. The cell cycle arrest, cell apoptosis induction, and PD-L1 expression level were measured by flow cytometry. A small molecular inhibitor was utilized to block STAT3 pathway, and the related proteins expression was measured by Western Blot.

RESULTS

The present study demonstrated that ATRA inhibited cell proliferation at 5-75 μmol/L, arrested cell cycle at S and G2-phase, induced apoptosis effect in OSCC, and oral dysplasia cell line, CAL27 and DOK, respectively. ATRA led to inhibition of p-STAT3, p-JAK2, increased the level of p-ERK, and significantly decreased the PD-L1 expression. Moreover, targeting STAT3 signaling increased (P < .001) the level of cleaved caspase-3 and effectively (P < .001) decreased the expression of cyclin A2 and PD-L1. The effect of ATRA on cell growth inhibition, apoptosis induction, and PD-L1 expression decrease was significantly (P < .05) enhanced after the STAT3 signaling blockade.

CONCLUSION

These findings suggested that ATRA-induced anti-tumor effects and downregulated PD-L1 expression via STAT3 signaling inhibition in both OSCC and oral dysplasia.

Downregulation of DHRS9 is associated with poor prognosis in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) has a high potential for local invasion and nodal metastasis. Therefore, early detection and elucidation of the detailed molecular mechanisms underlying OSCC are essential. Dehydrogenase/reductase member 9 (DHRS9) is downregulated in recurrent OSCC. Although DHRS9 is reported to act as a tumour suppressor in several malignancies, its expression in OSCC cells is unknown. In this study, we examined DHRS9 expression immunohistochemically in specimens from a sample of 98 OSCC patients. Reduced DHRS9 expression was observed in 68 of 98 patients (69.4%) with OSCC. A significant association was found between low DHRS9 expression and local progression (T factor) (p = 0.0135). Furthermore, patients with low DHRS9 expression had a significantly poorer prognosis than those with high DHRS9 expression (p = 0.0443). In multivariate analysis using the Cox proportional hazards model, decreased DHRS9 expression strongly correlated with worse prognosis. The study findings suggest that DHRS9 might be a useful diagnostic and prognostic marker for OSCC.

The telomere proteins in tumorigenesis and clinical outcomes of oral squamous cell carcinoma

The "Hallmarks of Cancer" describe the ways by which cancer cells bypass homeostasis. Escape from replicative senescence is one of the earliest features of cancer cells. Maintenance of the telomeres through reactivation of telomerase was initially associated with replicative immortality in various cancers. The shelterin complex, a telomeric hexaprotein association, plays a key role in telomere maintenance and in the hallmarks of cancer. Some shelterin proteins are overexpressed in diverse cancers and can promote tumorigenesis in animal models. Shelterin can also have an impact on tumor size, tumor growth and resistance to treatment. Studies into the expression level of shelterin in oral squamous cell carcinoma (OSCC) report contradictory results. Moreover, the exact role of these proteins in OSCC tumorigenesis remains uncertain. In this review, we examined the data linking telomeres and hallmarks of OSCC. Furthermore, we examined the literature concerning telomeres and the clinical outcome of OSCC. Finally, we propose a model encompassing the role of shelterin proteins in oral tumorigenesis and treatment outcome.

Antisense oligonucleotides targeting human telomerase mRNA increases the radiosensitivity of nasopharyngeal carcinoma cells

Nasopharyngeal carcinoma (NPC) is associated with a high incidence rate in South China and is predominantly treated with radiotherapy; however, the survival rate remains low. The therapeutic effects of radiation and chemotherapy may be enhanced when combined with anti‑sense oligonucleotides targeting human telomerase RNA (hTR ASODN). However, the influence of hTR ASODN on the anti‑tumor effects of radiation in NPC remain unknown. The present study investigated the effects of hTR ASODN on the proliferation and radiosensitivity of NPC cells, and further explored the underlying mechanisms. hTR ASODN significantly inhibited the proliferation and decreased the telomere length of CNE‑2 human NPC cells. Furthermore, combined treatment of hTR ASODN with radiation significantly enhanced anti‑tumor efficacy. The apoptotic rate and cleavage of caspase 9 were increased in the cells treated with the combined therapy, as compared with the cells treated with hTR ASODN or radiotherapy alone. In conclusion, these results suggest that hTR ASODN may inhibit the proliferation of NPC cells and enhance the anti‑tumor effects of radiation by inducing cell apoptosis. Therefore hTR ASODN may be a potential adjuvant agent for the treatment of NPC combined with radiation therapy, and these findings are of translational importance.

All-trans retinoic acid restores gap junctional intercellular communication between oral cancer cells with upregulation of Cx32 and Cx43 expressions in vitro

OBJECTIVE

All-trans retinoic acid (ATRA) has been demonstrated to inhibit tumor growth by restoration of gap junctional intercellular communication (GJIC) via upregulation of connexin (Cx) expression in some solid tumors. However, the relationship between ATRA and GJIC remains unclear in oral squamous cell carcinoma (OSCC). The aim of this study was to investigate the effect of ATRA on the GJIC function of OSCC.

STUDY DESIGN

We measured the effects of ATRA on the viability and cell cycle distribution of SCC9 and Tca8113 OSCC cells. The GJIC function was observed using the scrape-loading dye transfer technique, and the mRNA and protein levels of Cx32 and Cx43 were detected by qRT-PCR, Western blot, and immunofluorescence assays.

RESULTS

ATRA inhibited the growth of OSCC cells in a dose- and time-dependent manner (P <0.05) and caused cell cycle arrest. ATRA-treated cells showed a 2.69-fold and 2.06-fold enhancement of GJIC in SCC9 and Tca8113 cells, respectively (P <0.05). Moreover, ATRA induced upregulation of Cx32 and Cx43 at both the mRNA and protein levels in OSCC cells.

CONCLUSION

Our results indicated that restoration of GJIC via enhanced Cx32 and Cx43 expression might serve as a novel mechanism for the anti-tumor effect of ATRA in OSCC.

Is a swine model of arteriovenous malformation suitable for human extracranial arteriovenous malformation? A preliminary study

OBJECTIVE

A chronic arteriovenous malformation (AVM) model using the swine retia mirabilia (RMB) was developed and compared with the human extracranial AVM (EAVM) both in hemodynamics and pathology, to see if this brain AVM model can be used as an EAVM model.

METHODS

We created an arteriovenous fistula between the common carotid artery and the external jugular vein in eight animals by using end-to-end anastomosis. All animals were sacrificed 1 month after surgery, and the bilateral retia were obtained at autopsy and performed hematoxylin and eosin staining and immunohistochemistry. Pre- and postsurgical hemodynamic evaluations also were conducted. Then, the blood flow and histological changes of the animal model were compared with human EAVM.

RESULTS

The angiography after operation showed that the blood flow, like human EAVM, flowed from the feeding artery, via the nidus, drained to the draining vein. Microscopic examination showed dilated lumina and disrupted internal elastic lamina in both RMB of model and nidus of human EAVM, but the thickness of vessel wall had significant difference. Immunohistochemical reactivity for smooth muscle actin, angiopoietin 1, and angiopoietin 2 were similar in chronic model nidus microvessels and human EAVM, whereas vascular endothelial growth factor was significant difference between human EAVM and RMB of model.

CONCLUSIONS

The AVM model described here is similar to human EAVM in hemodynamics and immunohistochemical features, but there are still some differences in anatomy and pathogenetic mechanism. Further study is needed to evaluate the applicability and efficacy of this model.

The effects of 5-fluorouracil alone and in combination with 13-cis retinoic acid and vitamin D3 on human oral squamous cell carcinoma lines

AIM

Oral squamous cell carcinoma (OSCC) is responsible for about 90% of oral malignancies and its incidence is increasing. Despite various treatment protocols, survival rate of OSCC is low. Chemotherapy that is used for treating this carcinoma in advanced stages is systemic therapy that destroys carcinogenic cells, and controls tumor metastasis. Chemotherapy is very toxic and has limitations, especially for patients in advanced stages. Considering positive effects of retinoid and vitamin D3 derivatives in treating some carcinomas, we decided to evaluate the effect of combination of these drugs on OSCC. In this study the effects of combination of 5-fluorouracil, 13-cis retinoic acid and vitamin D3 on cultured cell of OSCC have been evaluated.

MATERIALS AND METHODS

OSCC cells were cultured in culture media and different concentration of 5-fluorouracil, 13-cis retinoic acid and vitamin D3 were added to cultured cell as separately and in combinations. The effect of treatment on cell proliferation and induction of apoptosis were evaluated by MTT and TUNEL assays respectively.

RESULTS

Combination of 5-fluorouracil and 13- cis retinoic acid had the highest inhibitory effect on SCC cell proliferation. Combination of two drugs had more apoptotic effect than each of them separately, and combination of three drugs had more effect than combination of two drugs.

CONCLUSION

Because combination of drugs had more inhibitory effect on cell proliferation than one of them and combination of three drugs had the most apoptotic effect than one of these drugs separately, these drugs may have synergic effect on OSCC.

CLINICAL SIGNIFICANCE

Combination of three drugs has more inhibitory effect on cell proliferation and apoptotic effect than one of these drugs.

Characterization of cancer stem-like cells in chordoma

OBJECT

Chordomas are locally aggressive bone tumors known to arise from the remnants of the notochord. Because chordomas are rare, molecular studies aimed at developing new therapies are scarce and new approaches are needed. Chordoma cells and cancer stem-like cells share similar characteristics, including self-renewal, differentiation, and resistance to chemotherapy. Therefore, it seems possible that chordomas might contain a subpopulation of cancer stem-like cells. The aim of this study is to determine whether cancer stem-like cells might be present in chordomas.

METHODS

In this study, the authors used gene expression analysis for common cancer stem-like cellmarkers, including c-myc, SSEA-1, oct4, klf4, sox2, nanog, and brachyury, and compared chordoma cells and tissues with nucleus pulposus tissues (disc degenerated nontumorigenic tissues). Differentiation through agents such as all-trans retinoic acid and osteogenic differentiation medium was induced to the chordoma cells. Additionally, U-CH1 cells were sorted via magnetic cell sorting for stem cell markers CD133 and CD15. After separation, positive and negative cells for these markers were grown in a nonadherent environment, soft agar, to determine whether the presence of these cancer stem-like cells might be responsible for initiating chordoma. The results were compared with those of untreated cells in terms of migration, proliferation, and gene expression by using reverse transcriptase polymerase chain reaction.

RESULTS

The results indicate that chordoma cells might be differentiating and committing into an osteogenic lineage when induced with the osteogenic differentiation agent. Chordoma cells that are induced with retinoic acid showed slower migration and proliferation rates when compared with the untreated cells. Chordoma cells that were found to be enriched by cancer stem-like cell markers, namely CD133 and CD15, were able to live in a nonadherent soft agar medium, demonstrating a self-renewal capability. To the authors' knowledge, this is the first time that cancer stem-like cell markers were also found to be expressed in chordoma cells and tissues.

CONCLUSIONS

Cancer stem-like cell detection might be an important step in determining the recurrent and metastatic characteristics of chordoma. This finding may lead to the development of new approaches toward treatments of chordomas.

Genome-wide transcriptional profiling analysis of all trans retinoic acid-treated tongue carcinoma SCC-9 cells

BACKGROUND

All trans retinoic acid (ATRA) is used as standard of care in promyelocytic leukemia. Not much is known about the gene expression profile in ATRA-treated tongue cancer cells. We performed a genome-wide transcriptional profiling of ATRA-treated tongue cancer cells to understand the pathways that mediate ATRA action in tongue cancer.

METHODS

We measured the effects of ATRA on the proliferation of SCC-9 human tongue carcinoma cells. The differential gene expression profile was measured by microarray analysis of untreated and ATRA-treated cells and expression of key genes was validated by real-time RT-PCR.

RESULTS

ATRA treatment (24 and 48 hr) significantly inhibited SCC-9 cell proliferation in a dose-dependent manner. SCC-9 cells treated for 48 hr with ATRA showed upregulation of 276 genes, including ANGPTL4, GDF15, ICAM1 and TUSC4, and downregulation of 43 genes, including CXCL10. Validation by real-time PCR showed a significant upregulation of intracellular adhesion molecule 1 (ICAM1) and downregulation of CXCL10 and IL32.

CONCLUSIONS

ATRA had an anti-tumor effect in tongue cancer cells. This effect is likely mediated via upregulation of ICAM1 and downregulation of CXCL10 and IL32.

Inhibiting adenoid cystic carcinoma cells growth and metastasis by blocking the expression of ADAM 10 using RNA interference

Background

Adenoid cystic carcinoma is one of the most common types of salivary gland cancers. The poor long-term prognosis for patients with adenoid cystic carcinoma is mainly due to local recurrence and distant metastasis. Disintegrin and metalloprotease 10 (ADAM 10) is a transmembrane protein associated with metastasis in a number of diverse of cancers. The aim of this study was to analyze the relationship between ADAM 10 and the invasive and metastatic potentials as well as the proliferation capability of adenoid cystic carcinoma cells in vitro and in vivo.

Methods

Immunohistochemistry and Western blot analysis were applied to detect ADAM 10 expression levels in metastatic cancer tissues, corresponding primary adenoid cystic carcinoma tissues, adenoid cystic carcinoma cell lines with high metastatic potential, and adenoid cystic carcinoma cell lines with low metastatic potential. RNA interference was used to knockdown ADAM 10 expression in adenoid cystic carcinoma cell lines with high metastatic potential. Furthermore, the invasive and metastatic potentials as well as the proliferation capability of the treated cells were observed in vitro and in vivo.

Results

It was observed that ADAM 10 was expressed at a significantly higher level in metastatic cancer tissues and in adenoid cystic carcinoma cell lines with high metastatic potential than in corresponding primary adenoid cystic carcinomas and adenoid cystic carcinoma cell lines with low metastatic potential. Additionally, silencing of ADAM 10 resulted in inhibition of cell growth and invasion in vitro as well as inhibition of cancer metastasis in an experimental murine model of lung metastases in vivo.

Conclusions

These studies suggested that ADAM 10 plays an important role in regulating proliferation and metastasis of adenoid cystic carcinoma cells. ADAM 10 is potentially an important therapeutic target for the prevention of tumor metastases in adenoid cystic carcinoma.

ATRA in combination with nedaplatin inhibits cell proliferation but promotes apoptosis in human hepatoma cell line Huh-7

AIM: To observe the effects of all-trans retinoic acid (ATRA) and nedaplatin, alone or in combination, on cell proliferation and apoptosis in human hepatoma cell line Huh-7, and to determine whether the two drugs in combination have a synergistic effect in treating hepatocarcinoma.

METHODS: After Huh-7 cells were incubated with different concentrations of ATRA (10^-4, 10^-5 and 10^-6 mol/L) and nedaplatin (1, 2 and 5 mg/L), alone or in combination, for 24, 48 and 72 h, cell morphology changes were observed using an inverted microscope; cell proliferation was evaluated by MTT assay; and apoptosis was evaluated by flow cytometry.

RESULTS: Both ATRA and nedaplatin could markedly inhibit cell proliferation in a time- and concentration-dependent manner (all P < 0.01). ATRA and nedaplatin in combination had a significant synergistic effect on cell proliferation compared with ATRA or nedaplatin alone (both P < 0.01). Both ATRA and nedaplatin promoted the apoptosis of Huh-7 cells. The apoptosis rate was significantly lower in Huh-7 cells treated with ATRA and nedaplatin alone for 48 h than in those treated with the two drugs in combination (28.49% ± 0.6%, 42.57% ± 1.03% vs 55.35% ± 1.30%, both P < 0.01), suggesting a synergistic effect of combined nedaplatin and ATRA on the apoptosis of Huh-7 cells.

CONCLUSION: Both ATRA and nedaplatin can inhibit cell proliferation and promote apoptosis in human hepatoma cell line Huh-7. ATRA combined with nedaplatin has a significant synergistic effect on the proliferation and apoptosis of Huh-7 cells.

A combination of the metabolic enzyme inhibitor APO866 and the immune adjuvant L-1-methyl tryptophan induces additive antitumor activity

Many types of malignant cells have a higher nicotinamide adenine dinucleotide (NAD) turnover rate than normal cells, as well as the ability to escape immune responses. Indoleamine 2,3-dioxygenase (IDO) is reported to be a negative immune regulator. Overexpression of IDO in dendritic cells is observed in tumor-draining lymph nodes. IDO-expressing dendritic cells suppress T-cell activation and promote immune tolerance. The nicotinamide phosphoribosyl transferase (NAMPT) inhibitor APO866 (also called FK866 or WK175) selectively inhibits tumor growth through intracellular NAD depletion. The IDO-specific inhibitor L-1-methyl-tryptophan (L-1MT) activates immune responses and reduces tumor volume in murine tumor models. We combined L-1MT and APO866 treatments and tested their antitumor effects in the murine gastric and bladder tumor models. In immune-competent mice, a combination of APO866 and L-1MT had a better therapeutic effect than did either L-1MT or APO866 alone. The intracellular level of NAD was suppressed by APO866 but not L-1MT. However, an additive inhibitory effect on tumor growth was not observed in tumor-bearing immune-deficient mice. The new strategy of combining a metabolic inhibitor and an immune adjuvant induced a potent therapeutic effect.

RNAi-mediated ADAM9 gene silencing inhibits metastasis of adenoid cystic carcinoma cells

A disintegrin and metalloproteinase 9 (ADAM9) is a type I transmembrane protein that has been associated with cancer development and metastases. Here, we show that ADAM9 is highly expressed in metastatic cancer tissues and in an adenoid cystic carcinoma cell line with a high metastatic potential. Using RNA interference for gene silencing, we show that ADAM9 is essential for in vitro cancer cell proliferation and invasion as well as in vivo cancer metastasis in an experimental murine model of lung metastases. These data indicate that ADAM9 is potentially an important new therapeutic target for the prevention of tumor metastases in adenoid cystic carcinoma.

The NF-kappa B inhibitor, celastrol, could enhance the anti-cancer effect of gambogic acid on oral squamous cell carcinoma

Background

Gambogic acid (GA) is a major active ingredient of gamboge, a widely used traditional Chinese medicine that has been reported to be a potent cytotoxic agent against some malignant tumors. Many studies have shown that the NF-kappa B signaling pathway plays an important role in anti-apoptosis and the drug resistance of tumor cells during chemotherapy. In this study, the effects and mechanisms of GA and the NF-kappa B inhibitor celastrol on oral cancer cells were investigated.

Methods

Three human oral squamous cell carcinoma cell lines, Tca8113, TSCC and NT, were treated with GA alone, celastrol alone or GA plus celastrol. Cytotoxicity was assessed by MTT assay. The rate of apoptosis was examined with annexin V/PI staining as well as transmission electronic microscopy in Tca8113 cells. The level of constitutive NF-kappa B activity in oral squamous cell carcinoma cell lines was determined by immunofluorescence assays and nuclear extracts and electrophoretic mobility shift assays (EMSAs) in vitro. To further investigate the role of NF-kappa B activity in GA and celastrol treatment in oral squamous cell carcinoma, we used the dominant negative mutant SR-IκBα to inhibit NF-kappa B activity and to observe its influence on the effect of GA.

Results

The results showed that GA could inhibit the proliferation and induce the apoptosis of the oral squamous cell carcinoma cell lines and that the NF-kappa B pathway was simultaneously activated by GA treatment. The minimal cytotoxic dose of celastrol was able to effectively suppress the GA-induced NF-kappa B pathway activation. Following the combined treatment with GA and the minimal cytotoxic dose of celastrol or the dominant negative mutant SR-IκBα, proliferation was significantly inhibited, and the apoptotic rate of Tca8113 cells was significantly increased.

Conclusion

The combination of GA and celastrol has a synergistic antitumor effect. The effect can be primarily attributed to apoptosis induced by a decrease in NF-kappa B pathway activation. The NF-kappa B signaling pathway plays an important role in this process. Therefore, combining GA and celastrol may be a promising modality for treating oral squamous cell carcinoma.