Lysicamine Reduces Protein Kinase B (AKT) Activation and Promotes Necrosis in Anaplastic Thyroid Cancer.

Anaplastic thyroid cancer (ATC) is an aggressive form of thyroid cancer (TC), accounting for 50% of total TC-related deaths. Although therapeutic approaches against TC have improved in recent years, the survival rate remains low, and severe adverse effects are commonly reported. However, unexplored alternatives based on natural compounds, such as lysicamine, an alkaloid found in plants with established cytotoxicity against breast and liver cancers, offer promise. Therefore, this study aimed to explore the antineoplastic effects of lysicamine in papillary TC (BCPAP) and ATC (HTH83 and KTC-2) cells. Lysicamine treatment reduced cell viability, motility, colony formation, and AKT activation while increasing the percentage of necrotic cells. The absence of caspase activity confirmed apoptosis-independent cell death. Necrostatin-1 (NEC-1)-mediated necrosome inhibition reduced lysicamine-induced necrosis in KTC-2, suggesting necroptosis induction via a reactive oxygen species (ROS)-independent mechanism. Additionally, in silico analysis predicted lysicamine target proteins, particularly those related to MAPK and TGF-ß signaling. Our study demonstrated lysicamine's potential as an antineoplastic compound in ATC cells with a proposed mechanism related to inhibiting AKT activation and inducing cell death.

The use of adenoviral vectors in gene therapy and vaccine approaches.

Adenovirus was first identified in the 1950s and since then this pathogenic group of viruses has been explored and transformed into a genetic transfer vehicle. Modification or deletion of few genes are necessary to transform it into a conditionally or non-replicative vector, creating a versatile tool capable of transducing different tissues and inducing high levels of transgene expression. In the early years of vector development, the application in monogenic diseases faced several hurdles, including short-term gene expression and even a fatality. On the other hand, an adenoviral delivery strategy for treatment of cancer was the first approved gene therapy product. There is an increasing interest in expressing transgenes with therapeutic potential targeting the cancer hallmarks, inhibiting metastasis, inducing cancer cell death or modulating the immune system to attack the tumor cells. Replicative adenovirus as vaccines may be even older and date to a few years of its discovery, application of non-replicative adenovirus for vaccination against different microorganisms has been investigated, but only recently, it demonstrated its full potential being one of the leading vaccination tools for COVID-19. This is not a new vector nor a new technology, but the result of decades of careful and intense work in this field.

TLR4 and SARM1 modulate survival and chemoresistance in an HPV-positive cervical cancer cell line.

Human Papillomavirus is responsible for a wide range of mucosal lesions and tumors. The immune system participate in tumorigenesis in different ways. For example, signaling pathways triggered by Toll-like receptors (TLR) play a role in chemotherapy resistance in several tumor types and are candidates for contributing to the development of HPV-induced tumors. Here, we studied the receptor TLR4 and the adaptor molecule SARM1 in HeLa cells, an HPV-positive cervical cancer cell line. Knocking out of these genes individually proved to be important for maintaining cell viability and proliferation. TLR4 knock out cells were more sensitive to cisplatin treatment, which was illustrated by an increased frequency of apoptotic cells. Furthermore, TLR4 and SARM1 modulated ROS production, which was induced by cell death in response to cisplatin. In conclusion, TLR4 and SARM1 are important for therapy resistance and cervical cancer cell viability and may be relevant clinical targets.

Metformin and Cancer Hallmarks: Molecular Mechanisms in Thyroid, Prostate and Head and Neck Cancer Models.

Metformin is the most used drug for type 2 diabetes (T2DM). Its antitumor activity has been described by clinical studies showing reduced risk of cancer development in T2DM patients, as well as management of T2DM compared with those receiving other glucose-lowering drugs. Metformin has a plethora of molecular actions in cancer cells. This review focused on in vitro data on the action mechanisms of metformin on thyroid, prostate and head and neck cancer. AMPK activation regulating specific downstream targets is a constant antineoplastic activity in different types of cancer; however, AMPK-independent mechanisms are also relevant. In vitro evidence makes it clear that depending on the type of tumor, metformin has different actions; its effects may be modulated by different cell conditions (for instance, presence of HPV infection), or it may regulate tissue-specific factors, such as the Na+/I- symporter (NIS) and androgen receptors. The hallmarks of cancer are a set of functional features acquired by the cell during malignant development. In vitro studies show that metformin regulates almost all the hallmarks of cancer. Interestingly, metformin is one of these therapeutic agents with the potential to synergize with other chemotherapeutic agents, with low cost, low side effects and high positive consequences. Some questions are still challenging: Are metformin in vitro data able to translate from bench to bedside? Does metformin affect drug resistance? Can metformin be used as a generic anticancer drug for all types of tumors? Which are the specific actions of metformin on the peculiarities of each type of cancer? Several clinical trials are in progress or have been concluded for repurposing metformin as an anticancer drug. The continuous efforts in the field and future in vitro studies will be essential to corroborate clinical trials results and to elucidate the raised questions.

Molecular mechanisms and pharmacological interventions in the replication cycle of human coronaviruses.

SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2), as well as SARS-CoV from 2003 along with MERS-CoV from 2012, is a member of the Betacoronavirus genus of the Nidovirales order and is currently the cause of the pandemic called COVID-19 (or Coronavirus disease 2019). COVID-19, which is characterized by cough, fever, fatigue, and severe cases of pneumonia, has affected more than 23 million people worldwide until August 25th, 2020. Here, we present a review of the cellular mechanisms associated with human coronavirus replication, including the unique molecular events related to the replication transcription complex (RTC) of coronaviruses. We also present information regarding the interactions between each viral protein and cellular proteins associated to known host-pathogen implications for the coronavirus biology. Finally, a specific topic addresses the current attempts for pharmacological interventions against COVID-19, highlighting the possible effects of each drug on the molecular events of viral replication. This review intends to aid future studies for a better understanding of the SARS-CoV-2 replication cycle and the development of pharmacological approaches targeting COVID-19.

HPV-Mediated Resistance to TNF and TRAIL Is Characterized by Global Alterations in Apoptosis Regulatory Factors, Dysregulation of Death Receptors, and Induction of ROS/RNS.

Persistent infection with high-risk human papilloma virus (HR-HPV) is the main risk factor for the development of invasive cervical cancer although is not sufficient to cause cervical cancer. Several host and environmental factors play a key role in cancer initiation/progression, including cytokines and other immune-response mediators. Here, we characterized the response to the individual and combined action of the pro-inflammatory cytokines tumor necrosis factor (TNF) and TNF-related apoptosis-inducing ligand (TRAIL) on HPV-transformed cells and human keratinocytes ectopically expressing E6 and E7 early proteins from different HPV types. We showed that keratinocytes expressing HPV early proteins exhibited global alterations in the expression of proteins involved in apoptosis regulation/execution, including TNF and TRAIL receptors. Besides, we provided evidence that TNF receptor 1 (TNFR1) was down-regulated and may be retained in the cytoplasm of keratinocytes expressing HPV16 oncoproteins. Finally, fluorescence analysis demonstrated that cytokine treatment induced the production and release of reactive oxygen and nitrogen species (ROS/RNS) in cells expressing HPV oncogenes. Alterations in ROS/RNS production and apoptosis regulatory factors expression in response to inflammatory mediators may favor the accumulation of genetic alterations in HPV-infected cells. Altogether, our results suggested that these events may contribute to lesion progression and cancer onset.

Oxidative stress: therapeutic approaches for cervical cancer treatment.

OBJECTIVES: Oxidative stress results from an imbalance between the generation and elimination of oxidant species. This condition may result in DNA, RNA and protein damage, leading to the accumulation of genetic alterations that can favor malignant transformation. Persistent infection with high-risk human papillomavirus types is associated with inflammatory responses and reactive oxygen species production. In this context, oxidative stress, chronic inflammation and high-risk human papillomavirus can act in a synergistic manner. To counteract the harmful effects of oxidant species, protective molecules, known as antioxidant defenses, are produced by cells to maintain redox homeostasis. In recent years, the use of natural antioxidants as therapeutic strategies for cancer treatment has attracted the attention of the scientific community. This review discusses specific molecules and mechanisms that can act against or together with oxidative stress, presenting alternatives for cervical cancer prevention and treatment.

Innate immunity and HPV: friends or foes.

Most human papillomavirus infections are readily cleared by the host immune response. However, in some individuals, human papillomavirus can establish a persistent infection. The persistence of high-risk human papillomavirus infection is the major risk factor for cervical cancer development. These viruses have developed mechanisms to evade the host immune system, which is an important step in persistence and, ultimately, in tumor development. Several cell types, receptors, transcription factors and inflammatory mediators involved in the antiviral immune response are viral targets and contribute to tumorigenesis. These targets include antigen-presenting cells, macrophages, natural killer cells, Toll-like receptors, nuclear factor kappa B and several cytokines and chemokines, such as interleukins, interferon and tumor necrosis factor. In the present review, we address both the main innate immune response mechanisms involved in HPV infection clearance and the viral strategies that promote viral persistence and may contribute to cancer development. Finally, we discuss the possibility of exploiting this knowledge to develop effective therapeutic strategies.

HPV-transformed cells exhibit altered HMGB1-TLR4/MyD88-SARM1 signaling axis.

Cervical cancer is one of the leading causes of cancer death in women worldwide. Persistent infection with high-risk human papillomavirus (HPV) types is the main risk factor for the development of cervical cancer precursor lesions. HPV persistence and tumor development is usually characterized by innate immune system evasion. Alterations in Toll-like receptors (TLR) expression and activation may be important for the control of HPV infections and could play a role in the progression of lesions and tumors. In the present study, we analyzed the mRNA expression of 84 genes involved in TLR signaling pathways. We observed that 80% of the differentially expressed genes were downregulated in cervical cancer cell lines relative to normal keratinocytes. Major alterations were detected in genes coding for several proteins of the TLR signaling axis, including TLR adaptor molecules and genes associated with MAPK pathway, NFκB activation and antiviral immune response. In particular, we observed major alterations in the HMGB1-TLR4 signaling axis. Functional analysis also showed that HMGB1 expression is important for the proliferative and tumorigenic potential of cervical cancer cell lines. Taken together, these data indicate that alterations in TLR signaling pathways may play a role in the oncogenic potential of cells expressing HPV oncogenes.

Oxidative stress: therapeutic approaches for cervical cancer treatment

OBJECTIVES: Oxidative stress results from an imbalance between the generation and elimination of oxidant species. This condition may result in DNA, RNA and protein damage, leading to the accumulation of genetic alterations that can favor malignant transformation. Persistent infection with high-risk human papillomavirus types is associated with inflammatory responses and reactive oxygen species production. In this context, oxidative stress, chronic inflammation and high-risk human papillomavirus can act in a synergistic manner. To counteract the harmful effects of oxidant species, protective molecules, known as antioxidant defenses, are produced by cells to maintain redox homeostasis. In recent years, the use of natural antioxidants as therapeutic strategies for cancer treatment has attracted the attention of the scientific community. This review discusses specific molecules and mechanisms that can act against or together with oxidative stress, presenting alternatives for cervical cancer prevention and treatment.

Innate immunity and HPV: friends or foes

Most human papillomavirus infections are readily cleared by the host immune response. However, in some individuals, human papillomavirus can establish a persistent infection. The persistence of high-risk human papillomavirus infection is the major risk factor for cervical cancer development. These viruses have developed mechanisms to evade the host immune system, which is an important step in persistence and, ultimately, in tumor development. Several cell types, receptors, transcription factors and inflammatory mediators involved in the antiviral immune response are viral targets and contribute to tumorigenesis. These targets include antigen-presenting cells, macrophages, natural killer cells, Toll-like receptors, nuclear factor kappa B and several cytokines and chemokines, such as interleukins, interferon and tumor necrosis factor. In the present review, we address both the main innate immune response mechanisms involved in HPV infection clearance and the viral strategies that promote viral persistence and may contribute to cancer development. Finally, we discuss the possibility of exploiting this knowledge to develop effective therapeutic strategies.

Efeito da infecção por HPV nas vias de sinalização por toll like receptors / Effects of HPV infection on TLR signaling pathway

As oncoproteínas E6 e E7 do Papilomavírus Humano (HPV) estão envolvidas na desregulação do sistema imune inato, provocando alterações na expressão dos receptores do tipo Toll (TLR). Considerando-se a função da via de sinalização iniciada por TLR, haveria uma vantagem para o vírus capaz de manipular a resposta desta via de modo que possa persistir nas células sem ser detectado pelo sistema imune ou ainda modulando essa resposta e criando um ambiente mais propício à manutenção da infecção. No entanto, muitos dos mecanismos que levam à eliminação da infecção ou persistência do HPV ainda são pouco conhecidos. O objetivo principal desse trabalho é investigar o papel das vias de TLR no processo de carcinogênese mediado por HPV. Inicialmente, foi analisada a expressão de genes da via de TLR em linhagens de tumores cervicais e em células expressando as oncoproteínas virais. Foram identificados vários genes diferencialmente expressos entre linhagens de células tumorais e queratinócitos normais, incluindo moléculas adaptadoras da via de TLR e genes associados à via da MAP quinase, ativação de NFkappaB e resposta imune antiviral. Cerca de 90% destes genes foram regulados negativamente. Entre eles, destacamos HMGB1, que apesar de possuir menos RNAm nas células tumorais possui um nível proteico muito maior, além de ter-se mostrado de grande importância para a viabilidade e proliferação das células tumorais, conforme demonstrado através de experimentos de supressão gênica. Em conjunto, os nossos dados indicam que E6 e E7 de HPVs de alto risco inibem proteínas da via de sinalização de TLR

Previous studies have shown that E6 and E7 HPV oncoproteins are involved in innate immune system dysregulation, causing alterations on Toll-like receptors (TLR) expression. Considering TLR pathway function, it would be advantageous for a virus to manipulate the response of this pathway so it can persist in cells without being detected by the immune system or to modulate this response to create a better environment for persistence of infection. However, many of the mechanisms leading to HPV infection clearance or persistence are still unknown and matter of active investigation. We analyzed in cervical cancer cell lines expression of genes from TLR pathway; several were differentially expressed between tumor cells lines and normal keratinocytes, including TLR adaptors molecules and genes associated with MAP kinase pathway, NFkappaB activation and antiviral immune response. About 90% of these genes were down regulated. Among them, we selected HMGB1 for further characterization due to its interference with tumor cell viability and proliferation. Altogether, our data indicate that high risk HPV E6 and E7 can inhibit TLR signaling pathway

Design, Immune Responses and Anti-Tumor Potential of an HPV16 E6E7 Multi-Epitope Vaccine.

Cervical cancer is a common type of cancer among women worldwide and infection with high-risk human papillomavirus (HPVs) types represents the major risk factor for the etiopathogenesis of the disease. HPV-16 is the most frequently identified HPV type in cervical lesions and expression of E6 and E7 oncoproteins is required for the uncontrolled cellular proliferation. In the present study we report the design and experimental testing of a recombinant multi-epitope protein containing immunogenic epitopes of HPV-16 E6 and E7. Tumor preventive assays, based on the engraftment of TC-1 cells in mice, showed that the E6E7 multi-epitope protein induced a full preventive anti-tumor protection in wild-type mice, as well as in mice deficient in expression of CD4+ T cells and TLR4 receptor. Nonetheless, no anti-tumor protection was observed in mice deficient in CD8+ T cells. Also, the vaccine promoted high activation of E6/E7-specific T cells and in a therapeutic-approach, E6E7 protein conferred full anti-tumor protection in mice. These results show a potential use of this E6E7 multi-epitope antigen as a new and promising antigen for the development of a therapeutic vaccine against tumors induced by HPV.