Unraveling Cancer's Wnt Signaling: Dynamic Control through Protein Kinase Regulation.

Since the initial identification of oncogenic Wnt in mice and Drosophila, the Wnt signaling pathway has been subjected to thorough and extensive investigation. Persistent activation of Wnt signaling exerts diverse cancer characteristics, encompassing tumor initiation, tumor growth, cell senescence, cell death, differentiation, and metastasis. Here we review the principal signaling mechanisms and the regulatory influence of pathway-intrinsic and extrinsic kinases on cancer progression. Additionally, we underscore the divergences and intricate interplays of the canonical and non-canonical Wnt signaling pathways and their critical influence in cancer pathophysiology, exhibiting both growth-promoting and growth-suppressing roles across diverse cancer types.

Unraveling the Role of Reactive Oxygen Species in T Lymphocyte Signaling.

Reactive oxygen species (ROS) are central to inter- and intracellular signaling. Their localized and transient effects are due to their short half-life, especially when generated in controlled amounts. Upon T cell receptor (TCR) activation, regulated ROS signaling is primarily initiated by complexes I and III of the electron transport chain (ETC). Subsequent ROS production triggers the activation of nicotinamide adenine dinucleotide phosphate oxidase 2 (NADPH oxidase 2), prolonging the oxidative signal. This signal then engages kinase signaling cascades such as the mitogen-activated protein kinase (MAPK) pathway and increases the activity of REDOX-sensitive transcription factors such as nuclear factor-kappa B (NF-κB) and activator protein-1 (AP-1). To limit ROS overproduction and prevent oxidative stress, nuclear factor erythroid 2-related factor 2 (Nrf2) and antioxidant proteins such as superoxide dismutases (SODs) finely regulate signal intensity and are capable of terminating the oxidative signal when needed. Thus, oxidative signals, such as T cell activation, are well-controlled and critical for cellular communication.

Insights in Molecular Therapies for Hepatocellular Carcinoma.

We conducted a comprehensive review of the current literature of published data and clinical trials (MEDLINE), as well as published congress contributions and active recruiting clinical trials on targeted therapies in hepatocellular carcinoma. Combinations of different agents and medical therapy along with radiological interventions were analyzed for the setting of advanced HCC. Those settings were also analyzed in combination with adjuvant situations after resection or radiological treatments. We summarized the current knowledge for each therapeutic setting and combination that currently is or has been under clinical evaluation. We further discuss the results in the background of current treatment guidelines. In addition, we review the pathophysiological mechanisms and pathways for each of these investigated targets and drugs to further elucidate the molecular background and underlying mechanisms of action. Established and recommended targeted treatment options that already exist for patients are considered for systemic treatment: atezolizumab/bevacizumab, durvalumab/tremelimumab, sorafenib, lenvatinib, cabozantinib, regorafenib, and ramucirumab. Combination treatment for systemic treatment and local ablative treatment or transarterial chemoembolization and adjuvant and neoadjuvant treatment strategies are under clinical investigation.

Current and Future Therapeutic Targets for Directed Molecular Therapies in Cholangiocarcinoma.

We conducted a comprehensive review of the current literature of published data, clinical trials (MEDLINE; ncbi.pubmed.com), congress contributions (asco.org; esmo.org), and active recruiting clinical trains (clinicaltrial.gov) on targeted therapies in cholangiocarcinoma. Palliative treatment regimens were analyzed as well as preoperative and perioperative treatment options. We summarized the current knowledge for each mutation and molecular pathway that is or has been under clinical evaluation and discussed the results on the background of current treatment guidelines. We established and recommended targeted treatment options that already exist for second-line settings, including IDH-, BRAF-, and NTRK-mutated tumors, as well as for FGFR2 fusion, HER2/neu-overexpression, and microsatellite instable tumors. Other options for targeted treatment include EGFR- or VEGF-dependent pathways, which are known to be overexpressed or dysregulated in this cancer type and are currently under clinical investigation. Targeted therapy in CCA is a hallmark of individualized medicine as these therapies aim to specifically block pathways that promote cancer cell growth and survival, leading to tumor shrinkage and improved patient outcomes based on the molecular profile of the tumor.

The p53 Family of Transcription Factors Represses the Alpha- fetoprotein Gene Expression in Hepatocellular Carcinoma.

BACKGROUND: p53 deletion and mutation as well as upregulation of alpha-fetoprotein (AFP) are hallmarks of hepatocarcinogenesis. p63 and p73 belong to the family of p53-related transcription factors expressing a variety of isoforms. The expression of dominant negative (ΔN) p73 is related to the reduced survival of patients with hepatocellular carcinoma (HCC). In this study, we characterized the interaction between p53 family-dependent signaling pathways and the regulation of AFP at the gene and protein levels as essential determinants of therapeutic response and prognosis in HCC. METHODS: Putative p53-, p63- and p73-binding sites within the AFP gene were identified in silico. Hep3B cells were transfected with plasmids encoding for p53, p63 and p73 to analyze the interplay of the p53 family with AFP. AFP transcription was determined by RT-qPCR. Protein levels of AFP, p53, p63 and p73 were analyzed by Western blot. RESULTS: Underlining the importance of the crosstalk between the p53 family-dependent pathways and AFP regulation we identified eight novel putative binding sites for the members of the p53 family within the introns 1, 2, 3, 4, 7, 8, 11, and 12 of the AFP gene. Accordingly, full-length isoforms of p53, p63 and p73 efficiently downregulated AFP both on mRNA and protein level. Thus, the p53 family members were identified to be major regulators of AFP repression. Of note, p63 was characterized as a novel and p73 as the most efficient repressor of AFP. CONCLUSION: p53 mutation and upregulation of AFP are essential oncogenic events in the development of HCC. Here we show that AFP gene regulation occurs via a combined action of the p53 family members p53, p63 and p73. All three tumor suppressors reduce AFP gene and protein expression. Thus, our findings reveal a novel interaction of p53 family-dependent signaling pathways and AFP regulation at the gene and protein levels in HCC.

Simultaneous Inhibition of Mcl-1 and Bcl-2 Induces Synergistic Cell Death in Hepatocellular Carcinoma.

Despite the recent approval of new therapies, the prognosis for patients with hepatocellular carcinoma (HCC) remains poor. There is a clinical need for new highly effective therapeutic options. Here, we present a combined application of BH3-mimetics as a potential new treatment option for HCC. BH3-mimetics inhibit anti-apoptotic proteins of the BCL-2 family and, thus, trigger the intrinsic apoptosis pathway. Anti-apoptotic BCL-2 proteins such as Bcl-2 and Mcl-1 are frequently overexpressed in HCC. Therefore, we analyzed the efficacy of the two BH3-mimetics ABT-199 (Bcl-2 inhibitor) and MIK665 (Mcl-1 inhibitor) in HCC cell lines with differential expression levels of endogenous Bcl-2 and Mcl-1. While administration of one BH3-mimetic alone did not substantially trigger cell death, the combination of two inhibitors enhanced induction of the intrinsic apoptosis pathway. Both drugs acted synergistically, highlighting the effectivity of this specific BH3-mimetic combination, particularly in HCC cell lines. These results indicate the potential of combining inhibitors of the BCL-2 family as new therapeutic options in HCC.

Comparing symptom reporting by prostate cancer patients and healthcare professionals in the international multicentre REQUITE study.

INTRODUCTION: Previous studies showed that healthcare professionals and patients had only moderate to low agreement on their assessment of treatment-related symptoms. We aimed to determine the levels of agreement in a large cohort of prostate cancer patients. METHODS: Analyses were made of data from 1,756 prostate cancer patients treated with external beam radiotherapy (RT) and/or brachytherapy in Europe and the USA and recruited into the prospective multicentre observational REQUITE study. Eleven pelvic symptoms at the end of RT were compared after translating patient-reported outcomes (PROs) into CTCAE-based healthcare professional ratings. Gwet's AC2 agreement coefficient and 95% confidence intervals were calculated for each symptom. To compare severity of grading between patients and healthcare professionals, percent agreement and deviations for each symptom were graphically depicted. Stratified and sensitivity analyses were conducted to identify potential influencing factors and to assess heterogeneity and robustness of results. RESULTS: The agreement for the 11 pelvic symptoms varied from very good (AC2 > 0.8: haematuria, rectal bleeding, management of sphincter control) to poor agreement (AC2 ≤ 0.2: proctitis and urinary urgency). Fatigue had a negative impact on the agreement. Patients tended to grade symptoms more severely than healthcare professionals. Information on sexual dysfunction was missing more frequently in healthcare professional assessment than PROs. CONCLUSION: Agreement was better for observable than subjective symptoms, with patients usually grading symptoms more severely than healthcare professionals. Our findings emphasize that PROs should complement symptom assessment by healthcare professionals and be taken into consideration for clinical decision-making to incorporate the patient perspective.

Case report: Predictability of clinical response and rejection risk after immune checkpoint inhibition in liver transplantation.

Background: The approval of Atezolizumab / Bevacizumab therapy (Atezo/Bev) in 2020 opened up a promising new treatment option for patients with end-stage hepatocellular carcinoma (HCC). However, liver transplant (LTx) patients with HCC are still denied this therapy owing to concerns about ICI-induced organ rejection and lack of regulatory approval. Methods: A prospective observational study at a tertiary liver transplant centre monitored the compassionate, off-label use of Atezo/Bev in a single, stable LTx recipient with non-resectable HCC recurrence. Close clinical, laboratory and immunological monitoring of the patient was performed throughout a four-cycle Atezo/Bev treatment. Measured parameters were selected after a systematic review of the literature on predictive markers for clinical response and risk of graft rejection caused by ICI therapy. Results: 19 articles describing 20 unique predictive biomarkers were identified. The most promising negative prognostic factors were the baseline values and dynamic course of IL-6, alpha-fetoprotein (AFP) and the AFP/CRP ratio. The frequency of regulatory T cells (Treg) reportedly correlates with the success of ICI therapy. PD-L1 and CD28 expression level with the allograft, peripheral blood CD4+ T cell numbers and Torque Teno Virus (TTV) titre may predict risk of LTx rejection following ICI therapy. No relevant side effects or acute rejection occurred during Atezo/Bev therapy; however, treatment did not prevent tumor progression. Absence of PD-L1 expression in pre-treatment liver biopsies, as well as a progressive downregulation of CD28 expression by CD4+ T cells during therapy, correctly predicted absence of rejection. Furthermore, increased IL-6 and AFP levels after starting therapy, as well as a reduction in blood Treg frequency, correctly anticipated a lack of therapeutic response. Conclusion: Atezo/Bev therapy for unresectable HCC in stable LTx patients remains a controversial strategy because it carries a high-risk of rejection and therapeutic response rates are poorly defined. Although previously described biomarkers of rejection risk and therapeutic response agreed with clinical outcomes in the described case, these immunological parameters are difficult to reliably interpret. Clearly, there is an important unmet need for standardized assays and clinically validated cut-offs before we use these biomarkers to guide treatment decisions for our patients.

Pathogenesis and Current Treatment Strategies of Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is the most frequent liver cancer with high lethality and low five-year survival rates leading to a substantial worldwide burden for healthcare systems. HCC initiation and progression are favored by different etiological risk factors including hepatitis B virus (HBV) and hepatitis C virus (HCV) infection, non-/and alcoholic fatty liver disease (N/AFLD), and tobacco smoking. In molecular pathogenesis, endogenous alteration in genetics (TP53, TERT, CTNNB1, etc.), epigenetics (DNA-methylation, miRNA, lncRNA, etc.), and dysregulation of key signaling pathways (Wnt/ß-catenin, JAK/STAT, etc.) strongly contribute to the development of HCC. The multitude and complexity of different pathomechanisms also reflect the difficulties in tailored medical therapy of HCC. Treatment options for HCC are strictly dependent on tumor staging and liver function, which are structured by the updated Barcelona Clinic Liver Cancer classification system. Surgical resection, local ablative techniques, and liver transplantation are valid and curative therapeutic options for early tumor stages. For multifocal and metastatic diseases, systemic therapy is recommended. While Sorafenib had been the standalone HCC first-line therapy for decades, recent developments had led to the approval of new treatment options as first-line as well as second-line treatment. Anti-PD-L1 directed combination therapies either with anti-VEGF directed agents or with anti-CTLA-4 active substances have been implemented as the new treatment standard in the first-line setting. However, data from clinical trials indicate different responses on specific therapeutic regimens depending on the underlying pathogenesis of hepatocellular cancer. Therefore, histopathological examinations have been re-emphasized by current international clinical guidelines in addition to the standardized radiological diagnosis using contrast-enhanced cross-sectional imaging. In this review, we emphasize the current knowledge on molecular pathogenesis of hepatocellular carcinoma. On this occasion, the treatment sequences for early and advanced tumor stages according to the recently updated Barcelona Clinic Liver Cancer classification system and the current algorithm of systemic therapy (first-, second-, and third-line treatment) are summarized. Furthermore, we discuss novel precautional and pre-therapeutic approaches including therapeutic vaccination, adoptive cell transfer, locoregional therapy enhancement, and non-coding RNA-based therapy as promising treatment options. These novel treatments may prolong overall survival rates in regard with quality of life and liver function as mainstay of HCC therapy.

Sympathetic denervation facilitates L-type Ca2+ channel activation in renal but not in mesenteric resistance arteries.

OBJECTIVES: Sympathetic denervation enhances agonist-induced vasoconstriction. This effect may involve altered function of signaling mechanisms such as Rho kinase (Rock) and L-type Ca channels downstream from vasoconstrictor receptors. We tested if enhanced Rock and L-type calcium channel activation contribute to exaggerated norepinephrine-induced vasoconstrictions in renal and mesenteric resistance arteries after sympathectomy. METHODS: Rats underwent neonatal sympathectomy or sham sympathectomy. Resistance arteries were investigated by small vessel myography. Vascular Rock and L-type Ca channel expression as well as Rock activation were investigated by quantitative real-time PCR and Western blot. Vascular smooth muscle cell (VSMC) membrane potential was recorded with microelectrodes. RESULTS: Sympathetic denervation enhanced norepinephrine sensitivity in renal and mesenteric arteries. Both, Rock inhibition or L-type Ca inhibition shifted the norepinephrine concentration-response curve to the right. This effect was more pronounced in renal than in mesenteric arteries from sympathectomized vs. sham-sympathectomized animals. The L-type Ca channel activator S-(-)-BayK8644 elicited strong vasoconstrictions only in renal arteries from sympathectomized rats. Rock activity and L-type Ca channel α-subunit expression were similar in renal arteries from sympathectomized and sham-sympathectomized animals. VSMC membrane potential was -57.5 ±â€Š2.0 and -64.3 ±â€Š0.3 mV (P < 0.01), respectively, in renal arteries from sympathectomized and from sham-sympathectomized rats. Depolarization enhanced and KATP channel activation abolished S-(-)-BayK8644-induced contractions in renal arteries from sympathectomized rats. CONCLUSION: Sympathetic denervation enhances L-type Ca channel-dependent signaling in renal but not in mesenteric arteries. This effect may be partly explained by the decreased VSMC membrane potential in denervated renal arteries.