Dual function of MyD88 in inflammation and oncogenesis: implications for therapeutic intervention

MyD88 and Its Inhibitors in Cancer: Prospects and Challenges

The interplay between the immune system and cancer underscores the central role of immunotherapy in cancer treatment. In this context, the innate immune system plays a critical role in preventing tumor invasion. Myeloid differentiation factor 88 (MyD88) is crucial for innate immunity, and activation of MyD88 promotes the production of inflammatory cytokines and induces infiltration, polarization, and immune escape of immune cells in the tumor microenvironment. Additionally, abnormal MyD88 signaling induces tumor cell proliferation and metastasis, which are closely associated with poor prognosis. Therefore, MyD88 could serve as a novel tumor biomarker and is a promising target for cancer therapy. Current strategies targeting MyD88 including inhibition of signaling pathways and protein multimerization, have made substantial progress, especially in inflammatory diseases and chronic inflammation-induced cancers. However, the specific role of MyD88 in regulating tumor immunity and tumorigenic mechanisms remains unclear. Therefore, this review describes the involvement of MyD88 in tumor immune escape and disease therapy. In addition, classical and non-classical MyD88 inhibitors were collated to provide insights into potential cancer treatment strategies. Despite several challenges and complexities, targeting MyD88 is a promising avenue for improving cancer treatment and has the potential to revolutionize patient outcomes.

Nano drug delivery systems for antisense oligonucleotides (ASO) therapeutics

Cancer, infectious diseases, and metabolic and hereditary genetic disorders are a global health burden affecting millions of people, with contemporary treatments offering limited relief. Antisense technology treats diseases by targeting their causal agents using its ability to alter or inhibit endogenous or malfunctioning genes. Nine antisense oligonucleotide (ASO) drugs that represent four different chemical classes have been approved for the treatment of rare diseases, including nusinersen, the first new oligonucleotide-based drug. Advances in medicinal chemistry, understanding the molecular pathways, and the availability of vast genetic data have resulted in enormous improvements in the therapeutic performance of ASO drugs; however, their susceptibility to degradation in the circulation, rapid renal clearance, and immunostimulatory adverse effects greatly limit their clinical applications. An increasing number of ASO-based therapeutics is being tested in clinical trials. Improvements to the delivery of ASO drugs could potentially change the therapeutic landscape for many conditions in the near future. This review describes the technological advances and developments in drug delivery systems pertaining to ASO therapeutics.

Holistic health record for Hidradenitis suppurativa patients

Hidradenitis suppurativa (HS) is a recurrent inflammatory skin disease with a complex etiopathogenesis whose treatment poses a challenge in the clinical practice. Here, we present a novel integrated pipeline produced by the European consortium BATMAN (Biomolecular Analysis for Tailored Medicine in Acne iNversa) aimed at investigating the molecular pathways involved in HS by developing new diagnosis algorithms and building cellular models to pave the way for personalized treatments. The objectives of our european Consortium are the following: (1) identify genetic variants and alterations in biological pathways associated with HS susceptibility, severity and response to treatment; (2) design in vitro two-dimensional epithelial cell and tri-dimensional skin models to unravel the HS molecular mechanisms; and (3) produce holistic health records HHR to complement medical observations by developing a smartphone application to monitor patients remotely. Dermatologists, geneticists, immunologists, molecular cell biologists, and computer science experts constitute the BATMAN consortium. Using a highly integrated approach, the BATMAN international team will identify novel biomarkers for HS diagnosis and generate new biological and technological tools to be used by the clinical community to assess HS severity, choose the most suitable therapy and follow the outcome.

LncRNA HOTAIR Participates in Microglia Activation and Inflammatory Factor Release by Regulating the Ubiquitination of MYD88 in Traumatic Brain Injury

Traumatic brain injury (TBI) is one of the leading causes of death worldwide. Long non-coding RNAs (LncRNAs) have been reported to be closely associated with various diseases, but their roles in TBI has not been fully elucidated. The purpose of this study was to elucidate the underlying mechanism of LncRNA HOTAIR in TBI-induced microglial activation and inflammatory factor release. In vivo mouse TBI model and in vitro microglia activation model were established by Feeney's free-fall impact method and by LPS stimulation, respectively. The expression of LncRNA HOTAIR in activated microglia was detected by qRT-PCR. After shRNA knocked down, the expressions of LncRNA HOTAIR and microglia activation marker Iba-1 in microglia were detected by qRT-PCR and Western blot and by ELISA that detected the concentration of inflammatory factor in cell culture supernatants. The relationship between LncRNA HOTAIR and MYD88 in mouse microglia BV2 cells was observed by RNA pull-down assay. Furthermore, the effect of LncRNA HOTAIR on MYD88 stability was assessed by cycloheximide (CHX)-chase and by immunoprecipitation and ubiquitination assays that analyzed MYD88 ubiquitination. LncRNA HOTAIR was abnormally highly expressed in activated microglia. By Western blot and ELISA, the knockdown of LncRNA HOTAIR in microglia significantly repressed microglia activation and inflammatory factor release. By RNA pull-down assay, LncRNA HOTAIR could bind to MYD88 protein. Besides, by cycloheximide (CHX)-chase and immunoprecipitation and ubiquitination assays, the overexpression of the LncRNA HOTAIR enhanced the stability of MYD88 protein and inhibited Nrdp1-mediated ubiquitination of MYD88 protein. After the transfection of shRNA-HOTAIR and shRNA-HOTAIR+pcDNA-MYD88 into microglia, shRNA-HOTAIR could significantly inhibit the activation of microglia and the release of inflammatory factors, while these effects were reversed after the transfection of pcDNA-MYD88. Our experimental data indicated that LncRNA HOTAIR was highly expressed in activated microglia, and our further studies had found that the interference with LncRNA HOTAIR could repress microglia activation and inflammatory factor release via promoting Nrdp1-mediated ubiquitination of MYD88 protein.

Toll-Like Receptor Characterization Correlates with Asthma and Is Predictive of Diagnosis

Toll-like receptors (TLRs) play crucial roles in the recognition of invading pathogens and the immune system. However, the effect of TLRs in asthma is still not fully known. This study was performed to better understand the role of TLR signatures in asthma. Blood samples from case-control studies (study 1: 348 asthmas and 39 normal controls and validation study 2: 411 asthmas and 87 normal controls) were enrolled. The single-sample gene set enrichment analysis method was performed to quantify the abundance of 21 TLR signatures. Gene ontology analysis and pathway function analysis were conducted for functional analysis, and a protein-protein interaction network was constructed. The area under the curve (AUC) value was used to assess the diagnostic capacity. In this study, TLR2/TLR3/TLR4 pathway, MyD88-dependent/independent TLR pathway, positive regulation of TLR4 pathway, and TLR binding signatures were significantly higher in asthma. Functional analysis showed that biological processes and pathways were still involved in TLR cascades and TLR signaling pathway. Eleven hub TLR-related genes were identified, and further validation demonstrated that the combination of TLR-related genes was a good diagnostic biomarker for asthma (AUC = 0.8). Our study provided more insight into the underlying immune mechanism of how TLR signatures affected asthma. The use of the easy-to-apply TLR-related genes might represent a promising blood-based biomarker for early detection of asthma.

Isoprenylcysteine Carboxyl Methyltransferase and Its Substrate Ras Are Critical Players Regulating TLR-Mediated Inflammatory Responses

In this study, we investigated the functional role of isoprenylcysteine carboxyl methyltransferase (ICMT) and its methylatable substrate Ras in Toll-like receptor (TLR)-activated macrophages and in mouse inflammatory disease conditions. ICMT and RAS expressions were strongly increased in macrophages under the activation conditions of TLRs by lipopolysaccharide (LPS, a TLR4 ligand), pam3CSK (TLR2), or poly(I:C) (TLR3) and in the colons, stomachs, and livers of mice with colitis, gastritis, and hepatitis. The inhibition and activation of ICMT and Ras through genetic and pharmacological approaches significantly affected the activation of interleukin-1 receptor-associated kinase (IRAK)s, tumor necrosis factor receptor associated factor 6 (TRAF6), transforming growth factor-β-activated kinase 1 (TAK1), mitogen-activated protein kinase (MAPK), and MAPK kinases (MAPKKs); translocation of the AP-1 family; and the expressions of inflammation-related genes that depend on both MyD88 and TRIF. Interestingly, the Ras/ICMT-mediated inflammatory reaction critically depends on the TIR domains of myeloid differentiation primary response 88 (MyD88) and TIR-domain-containing adapter-inducing interferon-β (TRIF). Taken together, these results suggest that ICMT and its methylated Ras play important roles in the regulation of inflammatory responses through cooperation with the TIR domain of adaptor molecules.

Implication of myeloid differentiation factor 88 inhibitor TJ-M2010-5 for therapeutic intervention of hepatocellular carcinoma

AIM

Myeloid differentiation factor 88 (MyD88) plays a key role in tumor proliferation and metastasis. Targeting MyD88 is a potent strategy in tumor therapy. TJ-M2010-5 is a small molecule derivative of aminothiazole and could inhibit dimer formation of MyD88. To explore the potential of TJ-M2010-5 in tumor therapy, we determined its antitumor effect and correlate mechanisms of TJ-M2010-5 in hepatocellular carcinoma (HCC).

METHODS

The antitumor effect of intratumoral injection of TJ-M2010-5 to H22 tumor-bearing BALB/c mice was observed. Tumor growth was monitored. The expression of MyD88 and Ki-67 were detected by immunofluorescence. In vitro, the impacts of TJ-M2010-5 on proliferation, cell cycle, necrosis, and apoptosis of H22 cells were evaluated. The direct and indirect effects of TJ-M2010-5 on macrophages were evaluated using flow cytometry.

RESULTS

TJ-M2010-5 induced both G₀ /G₁ and G₁ /S phase arrests in HCC cells. Mechanically, downstream activation of MyD88 was suppressed by TJ-M2010-5 through the extracellular regulated protein kinase-1/2/p90 ribosomal S6 kinase/glycogen synthase kinase-3β signaling pathway. In turn, cyclin-dependent kinase (CDK)6/cyclin D1 and CDK2/cyclin E complexes were downregulated. More importantly, TJ-M2010-5 significantly inhibited tumor growth in mice. Additionally, the portion of antitumor M1 macrophages (F4/80⁺ CD11c⁺ ) in the tumor microenvironment were increased after TJ-M2010-5 treatment. Together, these data indicate that TJ-M2010-5 is a promising therapeutic drug for HCC.

CONCLUSIONS

These results indicate that MyD88 is a feasible target for antitumor treatment and TJ-M2010-5 is a qualified candidate for HCC therapy.

TLR9 signaling in fibroblastic reticular cells regulates peritoneal immunity

Fibroblastic reticular cells (FRCs), a subpopulation of stromal cells in lymphoid organs and fat-associated lymphoid clusters (FALCs) in adipose tissue, play immune-regulatory roles in the host response to infection and may be useful as a form of cell therapy in sepsis. Here, we found an unexpected major role of TLR9 in controlling peritoneal immune cell recruitment and FALC formation at baseline and after sepsis induced by cecal ligation and puncture (CLP). TLR9 regulated peritoneal immunity via suppression of chemokine production by FRCs. Adoptive transfer of TLR9-deficient FRCs more effectively decreased mortality, bacterial load, and systemic inflammation after CLP than WT FRCs. Importantly, we found that activation of TLR9 signaling suppressed chemokine production by human adipose tissue-derived FRCs. Together, our results indicate that TLR9 plays critical roles in regulating peritoneal immunity via suppression of chemokine production by FRCs. These data form a knowledge basis upon which to design new therapeutic strategies to improve the therapeutic efficacy of FRC-based treatments for sepsis and immune dysregulation diseases.

Enhanced Potency of GalNAc-Conjugated Antisense Oligonucleotides in Hepatocellular Cancer Models

Antisense oligonucleotides (ASOs) are a novel therapeutic approach to target difficult-to-drug protein classes by targeting their corresponding mRNAs. Significantly enhanced ASO activity has been achieved by the targeted delivery of ASOs to selected tissues. One example is the targeted delivery of ASOs to hepatocytes, achieved with N-acetylgalactosamine (GalNAc) conjugation to ASO, which results in selective uptake by asialoglycoprotein receptor (ASGR). Here we have evaluated the potential of GalNAc-conjugated ASOs as a therapeutic approach to targeting difficult-to-drug pathways in hepatocellular carcinoma (HCC). The activity of GalNAc-conjugated ASOs was superior to that of the unconjugated parental ASO in ASGR (+) human HCC cells in vitro, but not in ASGR (-) cells. Both human- and mouse-derived HCC displayed reduced levels of ASGR, however, despite this, GalNAc-conjugated ASOs showed a 5- to 10-fold increase in potency in tumors. Systemically administered GalNAc-conjugated ASOs demonstrated both enhanced antisense activity and antitumor activity in the diethylnitrosamine-induced HCC tumor model. Finally, GalNAc conjugation enhanced ASO activity in human circulating tumor cells from HCC patients, demonstrating the potential of this approach in primary human HCC tumor cells. Taken together, these results provide a strong rationale for a potential therapeutic use of GalNAc-conjugated ASOs for the treatment of HCC.

An Integrated Approach to Unravel Hidradenitis Suppurativa Etiopathogenesis

Hidradenitis suppurativa/acne inversa (HS) is a chronic inflammatory disease involving hair follicles that presents with painful nodules, abscesses, fistulae, and hypertrophic scars, typically occurring in apocrine gland bearing skin. Establishing a diagnosis of HS may take up to 7 years after disease onset. HS severely impairs the quality of life of patients and its high frequency causes significant costs for health care system. HS patients have an increased risk of developing associated diseases, such as inflammatory bowel diseases and spondyloarthropathies, thereby suggesting a common pathophysiological mechanism. Familial cases, which are around 35% of HS patients, have allowed the identification of susceptibility genes. HS is perceived as a complex disease where environmental factors trigger chronic inflammation in the skin of genetically predisposed individuals. Despite the efforts made to understand HS etiopathogenesis, the exact mechanisms at the basis of the disease need to be still unraveled. In this review, we considered all OMICs studies performed on HS and observed that OMICs contribution in the context of HS appeared as not clear enough and/or rich of useful clinical information. Indeed, most studies focused only on one aspect—genome, transcriptome, or proteome—of the disease, enrolling small numbers of patients. This is quite limiting for the genetic studies, from different geographical areas and looking at a few aspects of HS pathogenesis without any integration of the findings obtained or a comparison among different studies. A strong need for an integrated approach using OMICs tools is required to discover novel actors involved in HS etiopathogenesis. Moreover, we suggest the constitution of consortia to enroll a higher number of patients to be analyzed following common and consensus OMICs strategies. Comparison and integration with the findings present in the OMICs repositories are mandatory. In a theoretic pipeline, the Skin-OMICs profile obtained from each HS patient should be compared and integrated with repositories and literature data by using appropriate InterOMICs approach. The final goal is not only to improve the knowledge of HS etiopathogenesis but also to provide novel tools to the clinicians with the eventual aim of offering a tailored treatment for HS patients.

An analysis of the expression and function of myeloid differentiation factor 88 in human osteosarcoma

The aim of the present study was to investigate the expression and function of myeloid differentiation factor 88 (MyD88) in osteosarcoma. Immunohistochemical staining was used to detect MyD88 protein in osteosarcoma tissues and matched normal bone tissues. The association between MyD88 expression and the clinical characteristics of patients with osteosarcoma was analyzed. Furthermore, survival analysis of patients with osteosarcoma was performed to study the association between MyD88 expression and patient prognosis. Finally, the effect of the MyD88 inhibitor, ST2825, on the proliferation and apoptosis of the human osteosarcoma cell line U2OS was examined. Additionally, cell proliferation, invasion and apoptosis were examined using an MTT assay, Transwell assay and Annexin V-fluorescein isothiocyanate staining kit, respectively. The expression of proteins associated with the NF-κB signaling pathway was analyzed by western blotting. The positive expression rate of MyD88 in osteosarcoma and normal bone tissues was 71.4 and 6.1%, respectively. Statistical analysis demonstrated that MyD88 was not associated with gender, age, histological type or tumor location, but that it was associated with Enneking stage and tumor metastasis (P<0.05). According to the survival analysis, patients with osteosarcoma in the high MyD88 expression group displayed a reduced overall survival rate (P<0.05). Furthermore, inhibition of MyD88 by ST2825 in U2OS cells resulted in a marked decrease in cellular proliferation and migration, and an increase in the rate of apoptosis (P<0.05). Notably, ST2825 significantly decreased cyclin D1, matrix metallopeptidase-9 and nucleus p65 expression, but increased cleaved-caspase 3 expression in ST2825-treated U2OS cells (P<0.05). The results of the present study indicated that MyD88 expression is associated with the progression of osteosarcoma and may be a potential therapeutic target for the treatment of osteosarcoma.

Bone marrow-specific loss of ABI1 induces myeloproliferative neoplasm with features resembling human myelofibrosis

Although the pathogenesis of primary myelofibrosis (PMF) and other myeloproliferative neoplasms (MPNs) is linked to constitutive activation of the JAK-STAT pathway, JAK inhibitors have neither curative nor MPN-stem cell-eradicating potential, indicating that other targetable mechanisms are contributing to the pathophysiology of MPNs. We previously demonstrated that Abelson interactor 1 (Abi-1), a negative regulator of Abelson kinase 1, functions as a tumor suppressor. Here we present data showing that bone marrow-specific deletion of Abi1 in a novel mouse model leads to development of an MPN-like phenotype resembling human PMF. Abi1 loss resulted in a significant increase in the activity of the Src family kinases (SFKs), STAT3, and NF-κB signaling. We also observed impairment of hematopoietic stem cell self-renewal and fitness, as evidenced in noncompetitive and competitive bone marrow transplant experiments. CD34⁺ hematopoietic progenitors and granulocytes from patients with PMF showed decreased levels of ABI1 transcript as well as increased activity of SFKs, STAT3, and NF-κB. In aggregate, our data link the loss of Abi-1 function to hyperactive SFKs/STAT3/NF-κB signaling and suggest that this signaling axis may represent a regulatory module involved in the molecular pathophysiology of PMF.

Human papillomavirus (HPV) 16 E6 oncoprotein targets the Toll-like receptor pathway

Cervical cancer is one of the leading causes of death in women worldwide and is etiologically linked to human papillomavirus (HPV) infection. Viral early proteins E6 and E7 manipulate cellular functions to promote the virus life cycle and are essential to the cellular transformation process. The innate immune system plays a pivotal role in the natural history of HPV infection. Among the various proteins that mediate the innate immune response, Toll-like receptors (TLRs) recognize pathogen-associated molecular patterns (PAMPs) and initiate the immune response. The objective of this study was to identify HPV E6 protein interaction partners in the TLR signalling pathway that may play a role in the immune response against HPV. Six TLR pathway proteins were shown to interact with HPV16 E6: myeloid differentiation primary response protein (MyD88), TIR domain-containing adapter molecule 1 (TRIF), interleukin-1 receptor-associated kinase-like (IRAK) 2, TNF receptor-associated factor (TRAF) 6, I-κB kinase beta (IKKβ) and I-κB kinase epsilon (IKKε). The interaction site of IKKε with E6 is located in the region containing the enzyme catalytic site, suggesting an influence of E6 on the activation of IKKε target proteins. HPV16 E6 potentiated the activation of NF-κB by various TLR pathway members. These results suggest that HPV16 has the ability to interfere with components of the immune response, contributing to HPV carcinogenesis.

Porphyromonas gingivalis Stimulates TLR2-PI3K Signaling to Escape Immune Clearance and Induce Bone Resorption Independently of MyD88

Porphyromonas gingivalis is a gram-negative anaerobic periodontal pathogen that persists in dysbiotic mixed-species biofilms alongside a dense inflammatory infiltrate of neutrophils and other leukocytes in the subgingival areas of the periodontium. Toll-like receptor 2 (TLR2) mediates the inflammatory response to P. gingivalis and TLR2-deficient mice resist alveolar bone resorption following oral challenge with this organism. Although, MyD88 is an adaptor protein considered necessary for TLR2-induced inflammation, we now report for the first time that oral challenge with P. gingivalis leads to alveolar bone resorption in the absence of MyD88. Indeed, in contrast to prototypical TLR2 agonists, such as the lipopeptide Pam3CSK4 that activates TLR2 in a strictly MyD88-dependent manner, P. gingivalis strikingly induced TLR2 signaling in neutrophils and macrophages regardless of the presence or absence of MyD88. Moreover, genetic or antibody-mediated inactivation of TLR2 completely reduced cytokine production in P. gingivalis-stimulated neutrophils or macrophages, suggesting that TLR2 plays a non-redundant role in the host response to P. gingivalis. In the absence of MyD88, inflammatory TLR2 signaling in P. gingivalis-stimulated neutrophils or macrophages depended upon PI3K. Intriguingly, TLR2-PI3K signaling was also critical to P. gingivalis evasion of killing by macrophages, since their ability to phagocytose this pathogen was reduced in a TLR2 and PI3K-dependent manner. Moreover, within those cells that did phagocytose bacteria, TLR2-PI3K signaling blocked phago-lysosomal maturation, thereby revealing a novel mechanism whereby P. gingivalis can enhance its intracellular survival. Therefore, P. gingivalis uncouples inflammation from bactericidal activity by substituting TLR2-PI3K in place of TLR2-MyD88 signaling. These findings further support the role of P. gingivalis as a keystone pathogen, which manipulates the host inflammatory response in a way that promotes bone loss but not bacterial clearance. Modulation of these host response factors may lead to novel therapeutic approaches to improve outcomes in disease conditions associated with P. gingivalis.

Clinical and pathological significance of myeloid differentiation factor 88 expression in human hepatocellular carcinoma tissues

The innate immune system, which includes toll-like receptor (TLR) signaling, plays an important role in inflammation and oncogenesis. Although TLR common adaptor myeloid differentiation factor 88 (MyD88) is known to have multiple effects on carcinogenesis, the role of MyD88 in hepatocarcinogenesis remains unknown. In this study, MyD88 expression was examined in 105 samples of human hepatocellular carcinoma (HCC) tissue by immunohistochemistry, Western blot, and quantitative reverse-transcriptase polymerase chain reaction methods. The relationships between MyD88 expression and clinical and pathological parameters were analyzed. The results showed that attenuated expression of MyD88 in HCC tissue tumor cells was significantly related to hepatitis B virus infection, large tumor size, positive vascular invasion, and intrahepatic metastasis (P < 0.05). Western blot analysis of MyD88 protein in nine normal livers and 28 HCCs showed gender disparity (P < 0.01, P < 0.05), and attenuated expression in cirrhotic livers (P < 0.05). Low expression of MyD88 mRNA was evident in HCCs with vascular invasion (P < 0.01). In contrast to previous reports, these results suggest that attenuated expression of MyD88 in HCC is associated with tumor progression.

MyD88 expression is associated with paclitaxel resistance in lung cancer A549 cells

The purpose of the present study was to investigate the relationship between myeloid differentiation primary response gene 88 (MyD88) expression and the resistance to paclitaxel of A549 lung cancer cells. In order to achieve MyD88 gene overexpression or knockdown in the A549 cell line, the cells were infected with lentivirus carrying MyD88 gene or shRNA to MyD88. MyD88 mRNA and protein expression was measured by RT-qPCR, immunohistochemistry and western blotting after infection for confirmation. Cell prolife-ration was detected by the WST-1 assay. Flow cytometry was used to measure the cell cycle and apoptosis. The transwell migration assay was used to observe the change of migration of transfected cells. The results showed that the overexpression of MyD88 increased the resistance of lung cancer A549 cells to paclitaxel, while the suppression of MyD88 increased the sensitivity of A549 lung cancer cells to paclitaxel. Following the paclitaxel treatment, a decreased apoptosis and G2 phase ratio, an increased cell migration ratio, and an increased production of IL-8 were found in MyD88‑overexpressed A549 cells. The western blot analysis revealed that Myd88 overexpression resulted in an increased level of Bcl-2 but a decreased level of Bax in A549 cells. These findings suggested that the expression level of MyD88 is closely associated with paclitaxel resistance in A549 lung cancer cells. Thus, the downregulation of MyD88 in A549 cells increased its sensitivity to paclitaxel treatment, whereas the upregulation of MyD88 substantiates its paclitaxel resistance.

Mechanisms of therapeutic resistance in cancer (stem) cells with emphasis on thyroid cancer cells

The two main reasons for death of cancer patients, tumor recurrence and metastasis, are multi-stage cellular processes that involve increased cell plasticity and coincide with elevated resistance to anti-cancer treatments. Epithelial-to-mesenchymal transition (EMT) is a key contributor to metastasis in many cancer types, including thyroid cancer and is known to confer stem cell-like properties onto cancer cells. This review provides an overview of molecular mechanisms and factors known to contribute to cancer cell plasticity and capable of enhancing cancer cell resistance to radio- and chemotherapy. We elucidate the role of DNA repair mechanisms in contributing to therapeutic resistance, with a special emphasis on thyroid cancer. Next, we explore the emerging roles of autophagy and damage-associated molecular pattern responses in EMT and chemoresistance in tumor cells. Finally, we demonstrate how cancer cells, including thyroid cancer cells, can highjack the oncofetal nucleoprotein high-mobility group A2 to gain increased transformative cell plasticity, prevent apoptosis, and enhance metastasis of chemoresistant tumor cells.