Exploiting new strategies in combating head and neck carcinoma: A comprehensive review on phytochemical approaches passing through PI3K/Akt/mTOR signaling pathway

Recently, malignant neoplasms have growingly caused human morbidity and mortality. Head and neck cancer (HNC) constitutes a substantial group of malignancies occurring in various anatomical regions of the head and neck, including lips, mouth, throat, larynx, nose, sinuses, oropharynx, hypopharynx, nasopharynx, and salivary glands. The present study addresses the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) pathway as a possible therapeutic target in cancer therapy. Finding new multitargeting agents capable of modulating PI3K/Akt/mTOR and cross-linked mediators could be viewed as an effective strategy in combating HNC. Recent studies have introduced phytochemicals as multitargeting agents and rich sources for finding and developing new therapeutic agents. Phytochemicals have exhibited immense anticancer effects, including targeting different stages of HNC through the modulation of several signaling pathways. Moreover, phenolic/polyphenolic compounds, alkaloids, terpenes/terpenoids, and other secondary metabolites have demonstrated promising anticancer activities because of their diverse pharmacological and biological properties like antiproliferative, antineoplastic, antioxidant, and anti-inflammatory activities. The current review is mainly focused on new therapeutic strategies for HNC passing through the PI3K/Akt/mTOR pathway as new strategies in combating HNC.

Indole Alkaloids, Synthetic Dimers and Hybrids with Potential In Vivo Anticancer Activity

Indole, a heterocyclic organic compound, is one of the most promising heterocycles found in natural and synthetic sources since its derivatives possess fascinating structural diversity and various therapeutic properties. Indole alkaloids, synthetic dimers and hybrids could act on diverse targets in cancer cells, and consequently, possess potential antiproliferative effects on various cancers both in vitro and in vivo. Vinblastine, midostaurin, and anlotinib as the representative of indole alkaloids, synthetic dimers and hybrids respectively, have already been clinically applied to treat many types of cancers, demonstrating indole alkaloids, synthetic dimers and hybrids are useful scaffolds for the development of novel anticancer agents. Covering articles published between 2010 and 2020, this review emphasizes the recent development of indole alkaloids, synthetic dimers and hybrids with potential in vivo therapeutic application for cancers.

Ethylcellulose microparticles enhance 3,3'-diindolylmethane anti-hypernociceptive action in an animal model of acute inflammatory pain

AIM

The present work aimed at the DIM-loaded microparticles development and anti-hypernociceptive action evaluation.

METHOD

The formulations were prepared by O/W solvent emulsion-evaporation method and characterised by particle diameter, content and DIM encapsulation efficiency, drug release profile, thermal behaviour and physicochemical state. The anti-hypernociceptive action was evaluated in the animal model of acute inflammatory pain.

RESULT

The MPs had a mean diameter in the micrometric range (368 ± 31 μm), narrow size distribution, DIM content of 150 mg/g, encapsulation efficiency around 84% and prolonged compound release. Evaluations of the association form of DIM to MPs demonstrated the feasibility of the systems to incorporate DIM and increases its thermal stability. An improvement in the anti-hypernociceptive action of DIM was observed by its microencapsuation, because it was increased and prolonged.

CONCLUSION

Therefore, the MPs developed represent a promising formulation for oral administration of the DIM in the treatment of inflammatory pain.

3,3'-Diindolylmethane nanoencapsulation improves its antinociceptive action: Physicochemical and behavioral studies

This study aimed to characterize the physicochemical properties of 3,3'-diindolylmethane (DIM)-loaded nanocapsules (NCs) as well as the antinociceptive effect using distinct animal models (hot plate test, formalin-induced nociception and complete Freud's adjuvant induced paw inflammation). The DIM-loaded NCs (composed by primula oil and ethylcellulose) were characterized using differential scanning calorimetry, thermogravimetric analysis, Fourier-transformed infrared spectroscopy, X-ray diffractometry and scanning electron microscopy. The physicochemical characterization demonstrated that DIM could be molecularly dispersed into the NCs, whose size was nanometric with a spherical shape. An improvement in DIM thermal stability was achieved by its encapsulation and there were no interactions among the formula components. For the nociceptive evaluation, male adult Swiss mice were pretreated with the NCs or free DIM by the intragastric route at the dose of 10 mg/Kg (time-response curve), 5 or 2.5 mg/Kg (dose-response curve). The behavioral tests were performed over an experimental period of 0.5-8 h. Both free and nanoencapsulated DIM reduced the mechanical hypernociception induced by CFA, mitigated nociceptive behavior of formalin-induced neurogenic and inflammatory pain and increased paw withdrawal latency assessed by the hot-plate test. Importantly, the DIM nanoencapsulation promoted a rapid initiation and prolonged the bioactive antinociceptive action (up to 8 h) as well as reduced the effective dose in comparison to its free form. In summary, this study reported that the NCs had adequate nanometric size, increased DIM stability and its antinociceptive action in different animal models, suggesting that the formulation may be a possible therapeutic alternative to the management of pain and inflammatory-related pathologies.

MicroRNA-Mediated Health-Promoting Effects of Phytochemicals

Phytochemicals are known to benefit human health by modulating various cellular processes, including cell proliferation, apoptosis, and inflammation. Due to the potential use of phytochemicals as therapeutic agents against human diseases such as cancer, studies are ongoing to elucidate the molecular mechanisms by which phytochemicals affect cellular functions. It has recently been shown that phytochemicals may regulate the expression of microRNAs (miRNAs). MiRNAs are responsible for the fine-tuning of gene expression by controlling the expression of their target mRNAs in both normal and pathological cells. This review summarizes the recent findings regarding phytochemicals that modulate miRNA expression and promote human health by exerting anticancer, photoprotective, and anti-hepatosteatosis effects. Identifying miRNAs modulated by phytochemicals and understanding the regulatory mechanisms mediated by their target mRNAs will facilitate the efforts to maximize the therapeutic benefits of phytochemicals.

3,3'-Diindolylmethane induces anti-human gastric cancer cells by the miR-30e-ATG5 modulating autophagy

3,3'-Diindolylmethane (DIM), a class of relatively non-toxic indole derivatives from cruciferous vegetables, has been reported as a promising anticancer phytochemical, but the underlying molecular mechanism is not completely elucidated. In the present study we report a novel regulation of autophagy by DIM in human gastric cancer cells. We found that DIM dose-dependently inhibited the growth of gastric cancer cells in vitro and in vivo. Moreover, ATG5 and LC3 were activated by DIM in gastric cancer cells. Furthermore, miR-30e was down-regulated by DIM and miR-30e targeted the 3'-UTR of ATG5 to inhibit its translation. Overall, these results suggest that DIM may through the miR-30e-ATG5 modulating autophagy inhibit the proliferation of gastric cancer cells.

Phenethyl isothiocyanate induces apoptosis and inhibits cell proliferation and invasion in Hep-2 laryngeal cancer cells

The dietary compound phenethyl isothiocyanate (PEITC), an important tumoricidal component found in cruciferous vegetables, exhibits strong anticancer and chemopreventive effects in a variety of tumors. However, its role in human laryngeal cancer is unclear. The aim of the present study was to investigate whether PEITC exhibits anticancer properties in human laryngeal carcinoma Hep-2 cells in vitro and to identify the potential molecular mechanisms. The results showed that treatment of Hep-2 cells with PEITC significantly inhibited cell proliferation in a dose- and time-dependent manner, promoted apoptosis with concurrent G2/M cell cycle arrest and inhibited cell invasion in a dose-dependent manner. These effects were accompanied by significant alterations in the expression levels of key proteins associated with pro-survival signaling pathways, including PI3K, Akt, ERK, NF-κB, Bcl, Bax, cyclin B, CDK4 and CDK6. Importantly, these effects were not reflected in 16HBE normal human bronchial epithelial cells, suggesting a safe range of treatment concentrations between 0 and 10 µM PEITC. In summary, PEITC exhibited significant anticancer effects against human laryngeal cancer cells in vitro with low toxicological impact on normal bronchial epithelial cells. This was achieved through dysregulation of key proteins involved in the occurrence and development of tumors, thereby offering a valuable contribution to future strategies for the treatment and screening of patients with laryngocarcinoma.

The bounty of nature for changing the cancer landscape

The landscape of cancer has changed considerably in past several years, due mainly to aggressive screening, accumulation of data from basic and epidemiological studies, and the advances in translational research. Natural anticancer agents have always been a part and parcel of cancer research. The initial focus on natural anticancer agents was in context of their cancer chemopreventive properties but their ability to selectively target oncogenic signaling pathways has also been recognized. In light of the rapid advancements in our understanding of the role of microRNAs, cancer stem cells, and epigenetic events in cancer initiation and progression, a number of natural anticancer agents are showing promise in vitro, in vivo as well as in preclinical studies. Moreover, parent structures of natural agents are being extensively modified with the hope of improving efficacy, specificity, and bioavailability. In this article, we focus on two natural agents, 3,3'-diindolylmethane and garcinol, along with 3,4-difluorobenzo curcumin, a synthetic analog of natural agent curcumin. We showcase how these anticancer agents are changing cancer landscape by modulating novel microRNAs, epigenetic factors, and cancer stem cell markers. These activities are relevant and being appreciated for overcoming drug resistance and inhibition of metastases, the two overarching clinical challenges in modern medicine.

ERK signaling mediates long-term low concentration 3,3'-diindolylmethane inhibited nasopharyngeal carcinoma growth and metastasis: An in vitro and in vivo study

It is well known that crucifers have antitumor effects and 3,3'-diindolylmethane (DIM) is one of the major bioactive components, and the associated molecular mechanisms in a short-term high-dose manner are widely discussed. However, the antitumor effects of DIM in a long-term low-dose manner in nasopharyngeal carcinoma (NPC) has not been reported yet, as to the potential mechanisms in the human body. In the present study, NPC cells were induced by 20 µmol/l DIM for over a month, and the proliferation, apoptosis, migration and in vivo metastasis were investigated. The results showed that DIM significantly reduced the proliferation and migration; however, changes in apoptosis were not observed. In vivo study showed the metastasis was significantly reduced. Compared to the short-term high-dose manner, incomplete similar qualities were observed; next we explored the possible signal pathway revolved, the ERK signaling showed similar changes, while the PI3K/Akt, NF-κB, P38, JNK pathways were significantly altered in the short-term high-dose manner (our previous study) showed no obvious change, indicating the ERK signaling may be the main effector of DIM.

Pro-apoptotic and anti-proliferative effects of 3,3'-diindolylmethane in nasopharyngeal carcinoma cells via downregulation of telomerase activity

The pro-apoptotic and anti-proliferative effects of 3,3'-diindolylmethane (DIM) in various tumor cell types have been widely investigated. The underlying mechanisms were suggested to include cell cycle arrest, cell signaling inhibition and downregulation of the androgen receptor. The present study demonstrated that DIM induced apoptosis and inhibited proliferation in nasopharyngeal carcinoma cells by downregulating the activity of telomerase. The nasopharyngeal carcinoma cell line 5‑8F was selected for this purpose. A cell counting kit‑8 assay and flow cytometry were performed to detect apoptosis and proliferation of 5‑8F cells, respectively, which revealed the pro‑apoptotic and anti‑proliferative effects of DIM. Telomerase activity was detected using a telomeric repeat amplification protocol assay, which revealed that the telomerase activity was inhibited by DIM in a dose‑dependent manner. Reverse transcription polymerase chain reaction was used to detect the mRNA expression levels of human telomerase reverse transcriptase (hTERT) and human telomerase RNA (hTR), and western blot analysis was used to detect the protein expression of hTERT. The results showed that the mRNA and protein expression of hTERT were downregulated in 5‑8F cells following treatment with DIM; however, the mRNA expression of hTR remained unchanged, suggesting that hTERT was the target of DIM. To further identify the target, the length of telomeres was continually measured using a telomere length detection kit, revealing that the telomeres were shortened by DIM in an concentration‑dependent manner. The present study confirmed that DIM had pro‑apoptotic and anti‑proliferative effects in nasopharyngeal carcinoma cells by regulating telomerase.

3,3'-Diindolylmethane inhibits the invasion and metastasis of nasopharyngeal carcinoma cells in vitro and in vivo by regulation of epithelial mesenchymal transition

Nasopharyngeal carcinoma (NPC) is characterized by silent progression and atypical early symptoms. Early metastasis to the neck lymph nodes is common. However, conventional chemoradiotherapy is limited and unable to effectively control cervical lymph node metastasis of NPC. In addition, toxicities caused by chemoradiotherapy often induce damage to normal tissues and organs. Thus, the aim of this study was to investigate the ability of 3,3′-diindolylmethane (DIM) to inhibit the invasion and metastasis of NPC cells in vitro and in vivo. The migration and invasive abilities of the 5–8F human NPC cell line were detected using a Transwell assay. Lymph node metastasis in nude mice was observed following the implantation of xenograft tumors for 8 weeks. In addition, western blot analysis was used to detect the expression levels of epithelial mesenchymal transition (EMT)-associated key proteins in NPC cells treated with DIM in vitro and in vivo. The results demonstrated that DIM effectively inhibited the migration and invasion of NPC cells in vitro and the effect was concentration-dependent. In addition, DIM significantly delayed and reduced the occurrence of lymph node metastasis in the animal model. The expression levels of a number of key proteins associated with EMT were affected by DIM treatment. In the animal model, there were no signs of toxicity in the vital organs, including the heart, liver and kidney, of animals fed a diet containing DIM. Therefore, the results of the present study indicate that DIM affects the expression levels of a number of EMT-associated key proteins and induces the inhibition of invasion and metastasis of NPC cells in vitro and in vivo.