CAR T-Cell-Based gene therapy for cancers: new perspectives, challenges, and clinical developments

Chimeric antigen receptor (CAR)-T cell therapy is a progressive new pillar in immune cell therapy for cancer. It has yielded remarkable clinical responses in patients with B-cell leukemia or lymphoma. Unfortunately, many challenges remain to be addressed to overcome its ineffectiveness in the treatment of other hematological and solidtumor malignancies. The major hurdles of CAR T-cell therapy are the associated severe life-threatening toxicities such as cytokine release syndrome and limited anti-tumor efficacy. In this review, we briefly discuss cancer immunotherapy and the genetic engineering of T cells and, In detail, the current innovations in CAR T-cell strategies to improve efficacy in treating solid tumors and hematologic malignancies. Furthermore, we also discuss the current challenges in CAR T-cell therapy and new CAR T-cell-derived nanovesicle therapy. Finally, strategies to overcome the current clinical challenges associated with CAR T-cell therapy are included as well

STING Agonist 8803 Reprograms the Immune Microenvironment and Increases Survival in Preclinical Models of Glioblastoma

STING agonists can reprogram the tumor microenvironment to induce immunological clearance within the central nervous system. Using multiplexed sequential immunofluorescence (SeqIF) and the Ivy Glioblastoma Atlas, STING expression was found in myeloid populations and in the perivascular space. The STING agonist 8803 increased median survival in multiple preclinical models of glioblastoma, including QPP8, an immune checkpoint blockade-resistant model, where 100% of mice were cured. Ex vivo flow cytometry profiling during the therapeutic window demonstrated increases in myeloid tumor trafficking and activation, alongside enhancement of CD8+ T cell and NK effector responses. Treatment with 8803 reprogrammed microglia to express costimulatory CD80/CD86 and iNOS, while decreasing immunosuppressive CD206 and arginase. In humanized mice, where tumor cell STING is epigenetically silenced, 8803 therapeutic activity was maintained, further attesting to myeloid dependency and reprogramming. Although the combination with a STAT3 inhibitor did not further enhance STING agonist activity, the addition of anti-PD-1 antibodies to 8803 treatment enhanced survival in an immune checkpoint blockade-responsive glioma model. In summary, 8803 as a monotherapy demonstrates marked in vivo therapeutic activity, meriting consideration for clinical translation

Utility of Keratins as Biomarkers for Human Oral Precancer and Cancer

Human oral cancer is the single largest group of malignancies in the Indian subcontinent and the sixth largest group of malignancies worldwide. Squamous cell carcinomas (SCC) are the most common epithelial malignancy of the oral cavity, constituting over 90% of oral cancers. About 90% of OSCCs arise from pre-existing, potentially malignant lesions. According to WHO, OSCC has a 5-year survival rate of 45–60%. Late diagnosis, recurrence, and regional or lymph nodal metastases could be the main causes of the high mortality rates. Biomarkers may help categorize and predict premalignant lesions as high risk of developing malignancy, local recurrence, and lymph nodal metastasis. However, at present, there is a dearth of such markers, and this is an area of ongoing research. Keratins (K) or cytokeratins are a group of intermediate filament proteins that show paired and differentiation dependent expression. Our laboratory and others have shown consistent alterations in the expression patterns of keratins in both oral precancerous lesions and tumors. The correlation of these changes with clinicopathological parameters has also been demonstrated. Furthermore, the functional significance of aberrant keratins 8/18 expression in the malignant transformation and progression of oral tumors has also been documented. This article reviews the literature that emphasizes the value of keratins as biomarkers for the prognostication of human oral precancers and cancers

Biomarker Potential of Vimentin in Oral Cancers

Oral carcinogenesis is a multistep process. As much as 5% to 85% of oral tumors can develop from potentially malignant disorders (PMD). Although the oral cavity is accessible for visual examination, the ability of current clinical or histological methods to predict the lesions that can progress to malignancy is limited. Thus, developing biological markers that will serve as an adjunct to histodiagnosis has become essential. Our previous studies comprehensively demonstrated that aberrant vimentin expression in oral premalignant lesions correlates to the degree of malignancy. Likewise, overwhelming research from various groups show a substantial contribution of vimentin in oral cancer progression. In this review, we have described studies on vimentin in oral cancers, to make a compelling case for vimentin as a prognostic biomarker

Tumor microenvironment signaling and therapeutics in cancer progression

Abstract Tumor development and metastasis are facilitated by the complex interactions between cancer cells and their microenvironment, which comprises stromal cells and extracellular matrix (ECM) components, among other factors. Stromal cells can adopt new phenotypes to promote tumor cell invasion. A deep understanding of the signaling pathways involved in cell‐to‐cell and cell‐to‐ECM interactions is needed to design effective intervention strategies that might interrupt these interactions. In this review, we describe the tumor microenvironment (TME) components and associated therapeutics. We discuss the clinical advances in the prevalent and newly discovered signaling pathways in the TME, the immune checkpoints and immunosuppressive chemokines, and currently used inhibitors targeting these pathways. These include both intrinsic and non‐autonomous tumor cell signaling pathways in the TME: protein kinase C (PKC) signaling, Notch, and transforming growth factor (TGF‐β) signaling, Endoplasmic Reticulum (ER) stress response, lactate signaling, Metabolic reprogramming, cyclic GMP–AMP synthase (cGAS)–stimulator of interferon genes (STING) and Siglec signaling pathways. We also discuss the recent advances in Programmed Cell Death Protein 1 (PD‐1), Cytotoxic T‐Lymphocyte Associated Protein 4 (CTLA4), T‐cell immunoglobulin mucin‐3 (TIM‐3) and Lymphocyte Activating Gene 3 (LAG3) immune checkpoint inhibitors along with the C‐C chemokine receptor 4 (CCR4)‐ C‐C class chemokines 22 (CCL22)/ and 17 (CCL17), C‐C chemokine receptor type 2 (CCR2)‐ chemokine (C‐C motif) ligand 2 (CCL2), C‐C chemokine receptor type 5 (CCR5)‐ chemokine (C‐C motif) ligand 3 (CCL3) chemokine signaling axis in the TME. In addition, this review provides a holistic understanding of the TME as we discuss the three‐dimensional and microfluidic models of the TME, which are believed to recapitulate the original characteristics of the patient tumor and hence may be used as a platform to study new mechanisms and screen for various anti‐cancer therapies. We further discuss the systemic influences of gut microbiota in TME reprogramming and treatment response. Overall, this review provides a comprehensive analysis of the diverse and most critical signaling pathways in the TME, highlighting the associated newest and critical preclinical and clinical studies along with their underlying biology. We highlight the importance of the most recent technologies of microfluidics and lab‐on‐chip models for TME research and also present an overview of extrinsic factors, such as the inhabitant human microbiome, which have the potential to modulate TME biology and drug responses

Ultrasound-mediated blood–brain barrier opening increases cell-free DNA in a time-dependent manner

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Vimentin regulates differentiation switch via modulation of keratin 14 levels and their expression together correlates with poor prognosis in oral cancer patients

<div><p>Vimentin is an intermediate filament protein, predominantly expressed in cells of mesenchymal origin, although its aberrant expression is seen in many carcinomas during epithelial mesenchymal transition. In cancer, vimentin expression is associated with the transition from a more differentiated epithelial phenotype to a dedifferentiated state. In view of the perceived role of keratins (Ks) as regulators of differentiation in epithelia, it was important to understand whether vimentin modulates differentiation through the reprogramming of keratins, in transformed cells. To address this, vimentin was stably downregulated in oral cancer derived cells. Further, global keratin profiling was performed after high salt keratin extraction. K5/K14 pair was found to be significantly downregulated, both at protein and mRNA levels upon vimentin downregulation. The previous study from our laboratory has shown a role of the K5/K14 pair in proliferation and differentiation of squamous epithelial cells. Vimentin depleted cells showed an increase in the differentiation state, marked by an increase in the levels of differentiation specific markers K1, involucrin, filaggrin and loricrin while its proliferation status remained unchanged. Rescue experiments with the K5/K14 pair overexpressed in vimentin knockdown background resulted in decreased differentiation state. ΔNp63 emerged as one of the indirect targets of vimentin, through which it modulates the expression levels of K5/K14. Further, immunohistochemistry showed a significant correlation between high vimentin-K14 expression and recurrence/poor survival in oral cancer patients. Thus, in conclusion, vimentin regulates the differentiation switch via modulation of K5/K14 expression. Moreover, vimentin-K14 together may prove to be the novel markers for the prognostication of human oral cancer.</p></div

List of proteins identified using MALDI analysis.

<p>List of proteins identified using MALDI analysis.</p

Downregulation of vimentin resulted in a change in the global keratin profile of the oral SCC derived cell line AW13516.

<p>(A) Schematic representation of the hypothesis. As a tumor cell acquires EMT (marked by upregulation of vimentin), it undergoes transition from a more epithelial-like to a more mesenchymal-like dedifferentiated state. To achieve this transition, there could be a vimentin mediated reprogramming of the keratins which distinguish these states. (B and C) Immunofluorescence (Bar: 10 μm) and western blot analysis of vimentin knockdown (shvim1 and shvim2) and its vector control clone (pTU6vc) using an antibody against vimentin. β-actin was used as the loading control in the western blotting experiment. (D) K8 levels of vimentin knockdown and its vector control clones were analyzed using western blotting. β-actin was used as a loading control. (E) The expression of K8 does not change upon vimentin downregulation. Thus, K8 was used as the loading control for high salt keratin enriched fraction. (F) Representative images of the 2D-gel, which show changes in keratin expression in the high salt keratin enriched fractions of vimentin knockdown and its vector control clones. The black circles indicate similarly expressed while the red circles indicate differentially expressed proteins. All the experiments were repeated independently in triplicates. For all the western blot experiments, the numbers below each blot represent the relative intensity of the bands determined using densitometry.</p

Vimentin mediated positive regulation of K5/K14 levels is not a cell line specific phenomenon.

<p>(A and B) Western blot analysis shows protein level of vimentin, K5, K14, K17 and involucrin in vimentin overexpressing clones of A431vim and HaCatvim as compared to its respective vector control clones A431vc and HaCatvc. Since A431 does not express K14, whole cell lysate from AW13516 was used as a positive control. (C) Whole cell lysates from DOK, AW13516 and AW8507 cells were probed with antibodies against vimentin, K5, K14 and involucrin respectively using western blotting. (D and E) Western blot and RT-PCR analysis of K14 and vimentin in K14 knockdown (shRK14-K7 and shRK14-K9) and its vector control clones (pTU6-AW1). GAPDH was used as the loading control in RT-PCR experiment. β-actin was used as the loading control in western blotting experiments. Western blotting experiments were done thrice with three independent sets of samples.</p