Expanded phenotype and cancer risk in patients with Beckwith-Wiedemann spectrum caused by CDKN1C variants.

Beckwith-Wiedemann spectrum (BWSp) is caused by genetic and epigenetic alterations on chromosome 11 that regulate cell growth and division. Considering the diverse phenotypic landscape in BWSp, the characterization of the CDKN1C molecular subtype remains relatively limited. Here, we investigate the role of CDKN1C in the broader BWSp phenotype. Notably, patients with CDKN1C variants appear to exhibit a different tumor risk than other BWSp molecular subtypes. We performed a comprehensive literature review using the search term "CDKN1C Beckwith" to identify 113 cases of patients with molecularly confirmed CDKN1C-BWSp. We then assessed the genotype and phenotype in a novel cohort of patients with CDKN1C-BWSp enrolled in the BWS Research Registry. Cardinal and suggestive features were evaluated for all patients reported, and tumor risk was established based on available reports. The most common phenotypes included macroglossia, omphalocele, and ear creases/pits. Tumor types reported from the literature included neuroblastoma, acute lymphocytic leukemia, superficial spreading melanoma, and intratubular germ cell neoplasia. Overall, this study identifies unique features associated with CDKN1C variants in BWSp, enabling more accurate clinical management. The absence of Wilms tumor and hepatoblastoma suggests that screening for these tumors may not be necessary, while the neuroblastoma risk warrants appropriate screening recommendations.

A Novel Macroglossia Severity Index for Beckwith-Wiedemann Syndrome.

OBJECTIVE/ SUMMARY BACKGROUND DATA: We propose the first classification scheme for macroglossia in patients with Beckwith-Wiedemann Syndrome (BWS), the BWS Index of macroGlossia (BIG). METHODS: Patients with molecularly confirmed BWS seen from 2004-2023 were included to develop this system. Relationships among BIG scores, tongue reduction surgery, BWS clinical score, percent mosaicism, and polysomnography findings were examined. RESULTS: Patients were classified from BIG0 to BIG3. BIG0 includes those without macroglossia; BIG1 includes those with macroglossia not protruding beyond the teeth/alveolus; BIG2 includes those with tongue protrusion past the teeth/alveolus to the lips but that can be contained within the mouth; and BIG3 includes those with tongues that protrude beyond the teeth/alveolus and lips but that cannot be closed within the mouth. Of the 459 patients with molecularly confirmed BWS, 266 (58.0%) patients were scored. One hundred and eleven (41.7%) were BIG0, 44 (16.5%) were BIG1, 90 (33.8%) were BIG2, and 21 (7.9%) were BIG3. As scores increased, patients had an increased incidence of tongue reduction surgery (BIG0: 0% versus BIG1: 20.5% versus BIG2: 51.1% versus BIG3: 100%; r=0.66, P <0.01). Higher BIG scores were associated with elevated BWS clinical scores (r=0.68, P <0.01) and increased tissue mosaicism (r=0.50, P <0.01) as well as trends towards worse obstructive apnea-hypopnea indices (r=0.29, P =0.02) and lower SpO 2 nadirs (r=-0.29, P =0.02). CONCLUSION: In this large series of patients with Beckwith-Wiedemann Syndrome, increased BIG score correlates with undergoing tongue reduction surgery and increased phenotypic severity. Adoption of the BIG scoring system may facilitate communication and risk stratification across institutions.

Publication Rates of Podium Presentations at an Annual Orthopedic Surgery Resident and Fellow Research Symposium.

Introduction Research is an important aspect of residency and fellowship programs across the country. Developing strategies to foster research productivity is worthwhile. An annual research project is one strategy that some programs implement. Methods All resident and fellow (Sports Medicine, Adult Reconstruction, Spine) presentations at an orthopedic surgery department's annual research symposium from June 2016 through June 2021 were identified. Abstract titles, title keywords, and author names were searched in PubMed and Google Scholar to identify the presence of a peer-reviewed publication. Using the total number of research symposium presentations given, the publication rate was calculated for each year, as well as collectively for 2016 to 2021. In addition to publication rate, first author percent, number of citations, Altmetric score, and journal impact factor were recorded. Current PGY-2 through PGY-5 residents completed a survey to assess the perceived value of the annual research symposium. Results Ninety-eight research symposium presentations were reviewed (69 residents, 29 fellows). Forty (58%) resident studies were published and 28 were first-author publications (70%). Thirteen (45%) fellow studies were published and seven were first-author publications (54%). Combining residents and fellows, the overall publication rate was 54% (53/98), and 66% of these (35/53) were first-author publications. There was a wide range of published manuscript journal impact factors, Altmetric scores, and number of citations. All residents surveyed reported finding value in the research symposium. Conclusion The overall publication rate of presentations at an annual orthopedic surgery department research symposium between 2016 and 2021 was 54%, consistent with publication rates reported at National Orthopedic Surgery Society meetings. All residents reported finding value in the annual research symposium. The results of this study support the academic value of implementing a required annual research project and may provide a useful gauge to inform residency and fellowship curricula at other institutions.

Post-operative protein supplementation following orthopaedic surgery: A systematic review.

Decreased mechanical loading after orthopaedic surgery predisposes patients to develop muscle atrophy. The purpose of this review was to assess whether the evidence supports oral protein supplementation can help decrease postoperative muscle atrophy and/or improve patient outcomes following orthopaedic surgery. A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). PubMed (MEDLINE), Embase, Scopus, and Web of Science were searched for randomized controlled trials that assessed protein or amino acid supplementation in patients undergoing orthopaedic surgery. Two investigators independently conducted the search using relevant Boolean operations. Primary outcomes included functional or physiologic measures of muscle atrophy or strength. Fourteen studies including 611 patients (224 males, 387 females) were analyzed. Three studies evaluated protein supplementation after ACL reconstruction (ACLR), 3 after total hip arthroplasty (THA), 5 after total knee arthroplasty (TKA), and 3 after surgical treatment of hip fracture. Protein supplementation showed beneficial effects across all types of surgery. The primary benefit was a decrease in muscle atrophy compared to placebo as measured by muscle cross sectional area. Multiple authors also demonstrated improved functional measures and quicker achievement of rehabilitation benchmarks. Protein supplementation has beneficial effects on mitigating muscle atrophy in the postoperative period following ACLR, THA, TKA, and surgical treatment of hip fracture. These effects often correlate with improved functional measures and quicker achievement of rehabilitation benchmarks. Further research is needed to evaluate long-term effects of protein supplementation and to establish standardized population-specific regimens that maximize treatment efficacy in the postoperative period.

Rehabilitation and return to sport criteria following surgical treatment of osteochondritis dissecans of the capitellum: a systematic review.

Background: Osteochondritis dissecans (OCD) of the capitellum is a well-described condition that most commonly affects adolescent throwing athletes and gymnasts. There is no gold standard rehabilitation protocol or timing for return to sport (RTS) after surgical management of OCD of the capitellum. Hypothesis/Purpose: The purpose of the study was to identify in the existing literature any criteria used for RTS following surgical treatment of OCD of the capitellum. The hypothesis was that surgeons would utilize length of time rather than functional criteria or performance benchmarks for RTS. Methods: Level 1 to 4 studies evaluating athletes who underwent surgery for OCD of the capitellum with a minimum follow-up of 1-year were included. Studies not describing RTS criteria, including less than 1-year follow-up, non-operative management only, and revision procedures were excluded. Each study was analyzed for RTS criteria, RTS rate, RTS timeline, sport played, level of competition, graft source (if utilized), and postoperative rehabilitation parameters. Assessment of bias and methodological quality was performed using the Coleman methodology score and RTS value assessment. Results: All studies reported a rehabilitation protocol with immobilization followed by bracing with progressive range of motion. RTS rate was 80.9% (233/288). The majority of studies reported using time-based criteria for RTS (11/15). The most commonly reported timeline was 6 months (range: 3-12 months). Conclusion: The overall RTS rate after surgical treatment of capitellar OCD is high with no consensus on RTS criteria. The two most consistent RTS criteria reported in the literature are return of elbow range of motion and healing demonstrated on postoperative imaging. There is a wide range of time to RTS in the literature, which may be sport dependent. Further research is needed to develop functional and performance-based metrics to better standardize RTS criteria and rehabilitation protocols.

Lower reproductive rates of Asian citrus psyllid (Hemiptera: Psyllidae) on 'Tahiti' acid lime than on 'Valencia' sweet orange

ABSTRACT The 'Tahiti' acid lime and orange trees are hosts of 'Candidatus Liberibacter asiaticus' (CLas), the pathogen associated with the severe Asian form of huanglongbing (HLB), the most devasting citrus disease. They are also hosts of the vector of CLas, the Asian citrus psyllid (ACP) Diaphorina citri Kuwayama. Relatively small numbers of lime trees occur in gardens and small orchards near large commercial 'Valencia' sweet orange orchards in Brazil. Applications of insecticides to suppress populations of ACP on the lime trees are usually nil or less frequent than in the orange orchards. Abundance of the psyllid on lime trees may therefore increase the risk of CLas spreading to the orchards. Because the abundance of the psyllid is influenced by the suitability of the trees as hosts, we compared reproductive potential of the insect on the two hosts in a controlled environment chamber (CEC) and in a greenhouse (GH). Daily temperature and relative humidity averaged 22ºC and 60% inside the CEC and 24°C and 70% inside the GH. Two pairs of adult male and female psyllids were caged for 3 days on new shoots and the fecundity and durations of development and survival of eggs and nymphs evaluated. Overall, acid 'Tahiti' was 3.5 times less suitable to ACP than 'Valencia'. Fecundity and survival of nymphs were 27% and 59% lower, and the life cycle 34% longer on 'Tahiti' than on 'Valencia'. Potential impacts of the results on CLas spread and HLB control are discussed.

Preclinical Synergistic Combination Therapy of Lurbinectedin with Irinotecan and 5-Fluorouracil in Pancreatic Cancer.

Pancreatic cancer is a devastating disease with a poor prognosis. Novel chemotherapeutics in pancreatic cancer have shown limited success, illustrating the urgent need for new treatments. Lurbinectedin (PM01183; LY-01017) received FDA approval in 2020 for metastatic small cell lung cancer on or after platinum-based chemotherapy and is currently undergoing clinical trials in a variety of tumor types. Lurbinectedin stalls and degrades RNA Polymerase II and introduces breaks in DNA, causing subsequent apoptosis. We now demonstrate lurbinectedin's highly efficient killing of human-derived pancreatic tumor cell lines PANC-1, BxPC-3, and HPAF-II as a single agent. We further demonstrate that a combination of lurbinectedin and irinotecan, a topoisomerase I inhibitor with FDA approval for advanced pancreatic cancer, results in the synergistic killing of pancreatic tumor cells. Western blot analysis of combination therapy indicates an upregulation of γH2AX, a DNA damage marker, and the Chk1/ATR pathway, which is involved in replicative stress and DNA damage response. We further demonstrate that the triple combination between lurbinectedin, irinotecan, and 5-fluorouracil (5-FU) results in a highly efficient killing of tumor cells. Our results are developing insights regarding molecular mechanisms underlying the therapeutic efficacy of a novel combination drug treatment for pancreatic cancer.

The role of p53 in anti-tumor immunity and response to immunotherapy.

p53 is a transcription factor that regulates the expression of genes involved in tumor suppression. p53 mutations mediate tumorigenesis and occur in approximately 50% of human cancers. p53 regulates hundreds of target genes that induce various cell fates including apoptosis, cell cycle arrest, and DNA damage repair. p53 also plays an important role in anti-tumor immunity by regulating TRAIL, DR5, TLRs, Fas, PKR, ULBP1/2, and CCL2; T-cell inhibitory ligand PD-L1; pro-inflammatory cytokines; immune cell activation state; and antigen presentation. Genetic alteration of p53 can contribute to immune evasion by influencing immune cell recruitment to the tumor, cytokine secretion in the TME, and inflammatory signaling pathways. In some contexts, p53 mutations increase neoantigen load which improves response to immune checkpoint inhibition. Therapeutic restoration of mutated p53 can restore anti-cancer immune cell infiltration and ameliorate pro-tumor signaling to induce tumor regression. Indeed, there is clinical evidence to suggest that restoring p53 can induce an anti-cancer immune response in immunologically cold tumors. Clinical trials investigating the combination of p53-restoring compounds or p53-based vaccines with immunotherapy have demonstrated anti-tumor immune activation and tumor regression with heterogeneity across cancer type. In this Review, we discuss the impact of wild-type and mutant p53 on the anti-tumor immune response, outline clinical progress as far as activating p53 to induce an immune response across a variety of cancer types, and highlight open questions limiting effective clinical translation.

Electromyography in the prognostication of recovery in patients with acute peripheral facial nerve palsy: A systematic review.

OBJECTIVES: Needle electromyography (EMG) may be used to characterise the severity of the injury in acute peripheral facial nerve palsy (FNP) to predict recovery and guide management, but its prognostic value and clinical utility remain controversial. The aim of this systematic review was to evaluate the role of EMG to prognosticate the recovery of facial motor function in patients with acute peripheral FNP. DESIGN: A comprehensive search strategy was applied in PubMed, Embase, and Web of Science based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The main outcome measure was the accuracy of EMG in predicting long-term facial function at least 6 months following symptom onset. RESULTS: Eleven studies were included comprising 3837 participants, with 91.6% of these diagnosed with Bell's palsy (BP). In BP patients, the positive predictive value and negative predictive value for a good outcome based on EMG findings ranged from 82.1% to 100% and 66.7% to 80.5%, respectively, with two out of three studies finding that EMG remained a significant predictor of the outcome on multivariate analysis. Three studies addressed the role of EMG in non-idiopathic FNP with two of these studies supporting EMG to predict prognosis. CONCLUSIONS: EMG is a useful tool to gain insight into the likely outcome to guide management decisions and counsel patients on their expectations, particularly in BP. However, given inconsistencies in its application and lack of evidence around non-idiopathic FNP, it should not currently be relied on to predict recovery. Ultimately, its prognostic value and widespread adoption are dependent on the implementation of a clear and standardised protocol in future high-quality studies and routine clinical settings.

Adoptive Cell Therapy in Hepatocellular Carcinoma: A Review of Clinical Trials.

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer. Immune checkpoint inhibitors (ICIs) have become the new reference standard in first-line HCC treatment, replacing tyrosine kinase inhibitors (TKIs) such as sorafenib. Many clinical trials with different combinations are already in development to validate novel immunotherapies for the treatment of patients with HCC. Adoptive cell therapy (ACT), also known as cellular immunotherapy, with chimeric antigen receptors (CAR) or gene-modified T cells expressing novel T cell receptors (TCR) may represent a promising alternative approach to modify the immune system to recognize tumor cells with better clinical outcomes. In this review, we briefly discuss the overview of ACT as a promising treatment modality in HCC, along with recent updates of ongoing clinical trials.

Tumor Suppressor p53 Down-Regulates Programmed Cell Death Protein 4 (PDCD4) Expression.

The programmed cell death protein 4 (PDCD4), a well-known tumor suppressor, inhibits translation initiation and cap-dependent translation by inhibiting the helicase activity of EIF4A. The EIF4A tends to target mRNAs with a structured 5'-UTR. In addition, PDCD4 can also prevent tumorigenesis by inhibiting tumor promoter-induced neoplastic transformation, and studies indicate that PDCD4 binding to certain mRNAs inhibits those mRNAs' translation. A previous study demonstrated that PDCD4 inhibits the translation of p53 mRNA and that treatment with DNA-damaging agents down-regulates PDCD4 expression but activates p53 expression. The study further demonstrated that treatment with DNA-damaging agents resulted in the downregulation of PDCD4 expression and an increase in p53 expression, suggesting a potential mechanism by which p53 regulates the expression of PDCD4. However, whether p53 directly regulates PDCD4 remains unknown. Herein, we demonstrate for the first time that p53 regulates PDCD4 expression. Firstly, we found that overexpression of p53 in p53-null cells (H1299 and Saos2 cells) decreased the PDCD4 protein level. Secondly, p53 decreased PDCD4 promoter activity in gene reporter assays. Moreover, we demonstrated that mutations in p53 (R273H: contact hotspot mutation, and R175H: conformational hotspot mutation) abolished p53-mediated PDCD4 repression. Furthermore, mutations in the DNA-binding domain, but not in the C-terminal regulatory domain, of p53 disrupted p53-mediated PDCD4 repression. Finally, the C-terminal regulatory domain truncation study showed that the region between aa374 and aa370 is critical for p53-mediated PDCD4 repression. Taken together, our results suggest that p53 functions as a novel regulator of PDCD4, and the relationship between p53 and PDCD4 may be involved in tumor development and progression.

Therapeutic targeting of TRAIL death receptors.

The discovery of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) along with its potent and selective antitumor effects initiated a decades-long search for therapeutic strategies to target the TRAIL pathway. First-generation approaches were focused on the development of TRAIL receptor agonists (TRAs), including recombinant human TRAIL (rhTRAIL) and TRAIL receptor-targeted agonistic antibodies. While such TRAIL pathway-targeted therapies showed promise in preclinical data and clinical trials have been conducted, none have advanced to FDA approval. Subsequent second-generation approaches focused on improving upon the specific limitations of first-generation approaches by ameliorating the pharmacokinetic profiles and agonistic abilities of TRAs as well as through combinatorial approaches to circumvent resistance. In this review, we summarize the successes and shortcomings of first- and second-generation TRAIL pathway-based therapies, concluding with an overview of the discovery and clinical introduction of ONC201, a compound with a unique mechanism of action that represents a new generation of TRAIL pathway-based approaches. We discuss preclinical and clinical findings in different tumor types and provide a unique perspective on translational directions of the field.

Familial Beckwith-Wiedemann syndrome in a multigenerational family: Forty years of careful phenotyping.

Beckwith-Wiedemann Spectrum (BWSp) is an overgrowth and cancer predisposition disorder characterized by a wide spectrum of phenotypic manifestations including macroglossia, abdominal wall defects, neonatal hypoglycemia, and predisposition to embryonal tumors. In 1981, Best and Hoekstra reported four patients with BWSp in a single family which suggested autosomal dominant inheritance, but standard clinical testing for BWSp was not available during this time. Meticulous phenotyping of this family has occurred over the past 40 years of follow-up with additional family members being identified and samples collected for genetic testing. Genetic testing revealed a pathogenic mutation in CDKN1C, consistent with the most common cause of familial BWSp. CDKN1C mutations account for just 5% of sporadic cases of BWSp. Here, we report the variable presentation of BWSp across the individuals affected by the CDKN1C mutation and other extended family members spanning multiple generations, all examined by the same physician. Additional phenotypes thought to be atypical in patients with BWSp were reported which included cardiac abnormalities. The incidence of tumors was documented in extended family members and included rhabdomyosarcoma, astrocytoma, and thyroid carcinoma, which have previously been reported in patients with BWSp. These observations suggest that in addition to the inheritance of the CDKN1C variant, there are modifying factors in this family driving the phenotypic spectrum observed. Alternative theories are suggested to explain the etiology of clinical variability including diffused mosaicism, anticipation, and the presence of additional variants tracking in the family. This study highlights the necessity of long-term follow-up in patients with BWSp and consideration of individual familial characteristics in the context of phenotype and/or (epi)genotype associations.

Cancer cell seeding density as a mechanism of chemotherapy resistance: a novel cancer cell density index based on IC50-Seeding Density Slope (ISDS) to assess chemosensitivity.

Although the 50% inhibitory concentration (IC50) is a commonly used measurement of chemosensitivity in cancer cells, it has been known to vary with the density of the treated cells (in that more densely seeded cells are more resistant to chemotherapeutic agents). Indeed, density-dependent chemoresistance may be a significant independent mechanism of therapy resistance. We examine the nature of cell density-dependent chemoresistance and explore possible underlying mechanisms. CellTiter-Glo assays and ethidium homodimer staining revealed that response to chemotherapy is density-dependent in all cancer cell lines tested. Our results prompted us to develop a novel cancer cell seeding density index of chemosensitivity, the ISDS (IC50-Seeding Density Slope), which we propose can serve as an improved method of analyzing how cancer cells respond to chemotherapeutic treatment compared to the widely-used IC50. Furthermore, western blot analysis suggests that levels of autophagy and apoptotic markers are modulated by cancer cell density. Cell viability experiments using the autophagy inhibitor chloroquine showed that chloroquine's efficacy was reduced at higher cell densities and that chloroquine and cisplatin exhibited synergy at both higher and lower cell densities in TOV-21G cells. We discuss alternative mechanisms of density-dependent chemoresistance and in vivo/clinical applications, including challenges of adjuvant chemotherapy and minimal residual disease. Taken together, our findings show that cell density is a significant contributor in shaping cancer chemosensitivity, that the ISDS (aka the Ujwal Punyamurtula/Wafik El-Deiry or Ujwal-WAF Index) can be used to effectively assess cell viability and that this phenomenon of density-dependent chemoresistance may be leveraged for a variety of biologic and cancer therapeutic applications.

A Case of Hemorrhagic Ovarian Cyst Rupture Necessitating Surgical Intervention.

Despite the relatively high incidence of ovarian cysts, particularly in premenopausal women, cyst rupture may on occasion present painfully and require surgical intervention to resolve. Particularly in the case of ruptured hemorrhagic ovarian cysts, resulting hemoperitoneum can create a risk of further adverse events including hypovolemic shock; proper identification and management of such cases are therefore critical. This case focuses on a 22-year-old female that presented to the emergency department (ED) with suprapubic pain in the lower left quadrant of the abdomen. Ultrasonography and computed tomography of the abdomen and pelvis revealed a ruptured hemorrhagic corpus luteum cyst of the left ovary and secondary hemoperitoneum. Patient treatment required laparoscopic left ovarian cyst wall removal, with the removal of hemoperitoneum.

Enhancing SIRT1 Gene Expression Using Small Activating RNAs: A Novel Approach for Reversing Metabolic Syndrome.

Metabolic syndrome (MetS) is a pathological condition characterized by abdominal obesity, insulin resistance, hypertension, and hyperlipidemia. Sirtuin 1 (SIRT1), a highly conserved histone deacetylase, is characterized as a key metabolic regulator and protector against aging-associated pathologies, including MetS. In this study, we investigate the therapeutic potential of activating SIRT1 using small activating RNAs (saRNA), thereby reducing inflammatory-like responses and re-establishing normal lipid metabolism. SIRT1 saRNA significantly increased SIRT1 messenger RNA (mRNA) and protein levels in both lipopolysaccharide-stimulated and nonstimulated macrophages. SIRT1 saRNA significantly decreased inflammatory-like responses, by reducing mRNA levels of key inflammatory cytokines, such as Tumor Necrosis Factor alpha, Interleukin 1 beta (IL-1ß), Interleukin 6 (IL-6), and chemokines Monocyte Chemoattractant Protein-1 and keratinocyte chemoattractant. SIRT1 overexpression also significantly reduced phosphorylation of nuclear factor-κB and c-Jun N-terminal kinase, both key signaling molecules for the inflammatory pathway. To investigate the therapeutic effect of SIRT1 upregulation, we treated a high-fat diet model with SIRT1 saRNA conjugated to a transferrin receptor aptamer for delivery to the liver and cellular internalization. Animals in the SIRT1 saRNA treatment arm demonstrated significantly decreased weight gain with a significant reduction in white adipose tissue, triglycerides, fasting glucose levels, and intracellular lipid accumulation. These suggest treatment-induced changes to lipid and glucose metabolism in the animals. The results of this study demonstrate that targeted activation of SIRT1 by saRNAs is a potential strategy to reverse MetS.

The Role of Immune Checkpoint Blockade in the Hepatocellular Carcinoma: A Review of Clinical Trials.

The prevalence of primary liver cancer is rapidly rising all around the world. Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer. Unfortunately, the traditional treatment methods to cure HCC showed poor efficacy in patients who are not candidates for liver transplantation. Until recently, tyrosine kinase inhibitors (TKIs) were the front-line treatment for unresectable liver cancer. However, rapidly emerging new data has drastically changed the landscape of HCC treatment. The combination treatment of atezolizumab plus bevacizumab (immunotherapy plus anti-VEGF) was shown to provide superior outcomes and has become the new standard first-line treatment for unresectable or metastatic HCC. Currently, ongoing clinical trials with immune checkpoint blockade (ICB) have focused on assessing the benefit of antibodies against programmed cell death 1 (PD-1), programmed cell death-ligand 1 (PD-L1), and cytotoxic T-lymphocyte- associated antigen 4 (CTLA-4) as monotherapies or combination therapies in patients with HCC. In this review, we briefly discuss the mechanisms underlying various novel immune checkpoint blockade therapies and combination modalities along with recent/ongoing clinical trials which may generate innovative new treatment approaches with potential new FDA approvals for HCC treatment in the near future.

Therapeutic Targeting of Alternative RNA Splicing in Gastrointestinal Malignancies and Other Cancers.

Recent comprehensive genomic studies including single-cell RNA sequencing and characterization have revealed multiple processes by which protein-coding and noncoding RNA processing are dysregulated in many cancers. More specifically, the abnormal regulation of mRNA and precursor mRNA (pre-mRNA) processing, which includes the removal of introns by splicing, is frequently altered in tumors, producing multiple different isoforms and diversifying protein expression. These alterations in RNA processing result in numerous cancer-specific mRNAs and pathogenically spliced events that generate altered levels of normal proteins or proteins with new functions, leading to the activation of oncogenes or the inactivation of tumor suppressor genes. Abnormally spliced pre-mRNAs are also associated with resistance to cancer treatment, and certain cancers are highly sensitive to the pharmacological inhibition of splicing. The discovery of these alterations in RNA processing has not only provided new insights into cancer pathogenesis but identified novel therapeutic vulnerabilities and therapeutic opportunities in targeting these aberrations in various ways (e.g., small molecules, splice-switching oligonucleotides (SSOs), and protein therapies) to modulate alternative RNA splicing or other RNA processing and modification mechanisms. Some of these strategies are currently progressing toward clinical development or are already in clinical trials. Additionally, tumor-specific neoantigens produced from these pathogenically spliced events and other abnormal RNA processes provide a potentially extensive source of tumor-specific therapeutic antigens (TAs) for targeted cancer immunotherapy. Moreover, a better understanding of the molecular mechanisms associated with aberrant RNA processes and the biological impact they play might provide insights into cancer initiation, progression, and metastasis. Our goal is to highlight key alternative RNA splicing and processing mechanisms and their roles in cancer pathophysiology as well as emerging therapeutic alternative splicing targets in cancer, particularly in gastrointestinal (GI) malignancies.

SARS-CoV-2: Pathogenic Mechanisms and Host Immune Response.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an enveloped, positive-sense RNA coronavirus responsible for the COVID-19 pandemic. Since December 2019, coronavirus disease 2019 (COVID-19) has affected more than 127 million people, 2.7 million deaths globally (as per WHO dashboard, dated 31 March, 2020), the virus is capable of transmitting from human to human via inhalation of infected respiratory droplets or aerosols or contact with infected fomites. Clinically, patients with COVID-19 present with severe respiratory distress syndrome, which is very similar to the presentation of other respiratory viral infections. A huge variation in the host response exists, with the resulting symptoms varying from mild to moderate. Comorbidities such as cardiovascular disease, hypertension, diabetes, coagulation dysfunction, stroke, malignant tumor and multiple organ dysfunction syndrome, as well as age and sex, are associated with severe COVID-19 cases. So far, no targeted therapies have been developed to treat this disease and existing drugs are being investigated for repurposing. This chapter discusses the epidemiology, clinical features of COVID-19, pathogenesis and the innate and adaptive immune response mounted by the host to the SARS-CoV-2 infection. A deeper understanding of the host-pathogen interaction is fundamental to the development of a vaccine.

Hyperprogression of a mismatch repair-deficient colon cancer in a humanized mouse model following administration of immune checkpoint inhibitor pembrolizumab.

Immunotherapy is an established treatment modality in oncology. However, in addition to primary or acquired therapy resistance with immune checkpoint blockade (ICB), hyperprogressive disease (HPD) or hyperprogression (HP) with acceleration of tumor growth occurs in a subset of patients receiving ICB therapy. A validated and predictive animal model would help investigate HPD/HP to develop new approaches for this challenging clinical entity. Using human cytotoxic T-cell line TALL-104 injected intraperitoneally into immunodeficient NCRU-nude athymic mice bearing mismatch repair-deficient (MMR-d) human colon carcinoma HCT116 p53-null (but not wild-type p53) tumor xenograft, we observed accelerated tumor growth after PD-1 blockade with pembrolizumab administration. There was increased colon tumor cell proliferation as determined by immunohistochemical Ki67 staining of tumor sections. There was no increase in MDM2 or MDM4/MDMX in the p53-null HCT116 cells versus the wild-type p53-expressing isogenic tumor cells, suggesting the effects in this model may be MDM2 or MDM4/MDMX-independent. Human cytokine profiling revealed changes in IFN-γ, TRAIL-R2/TNFRSF10B, TRANCE/TNFSF11/RANK L, CCL2/JE/MCP-1, Chitinase 3-like 1, IL-4 and TNF-α. This represents a novel humanized HPD mouse model with a link to deficiency of the p53 pathway of tumor suppression in the setting of MMR-d. Our novel humanized preclinical TALL-104/p53-null HCT116 mouse model implicates p53-deficiency in an MMR-d tumor as a possible contributor to HPD/HP and may help with evaluating therapeutic strategies in cancer immunotherapy to extend clinical benefits of ICB's in a broader patient population.