Potential impact of mTOR inhibitors on cervical squamous cell carcinoma: A systematic review

The Mutational and Microenvironmental Landscape of Cutaneous Squamous Cell Carcinoma: A Review

Cutaneous squamous cell carcinoma (cSCC) manifests through the complex interactions of UV-induced DNA damage, genetic mutations, and alterations in the tumor microenvironment. A high mutational burden is present in cSCC, as well as both cSCC precursors and normal skin, making driver genes difficult to differentiate. Despite this, several key driver genes have been identified, including TP53, the NOTCH family, CDKN2A, PIK3CA, and EGFR. In addition to mutations, the tumor microenvironment and the manipulation and evasion of the immune system play a critical role in cSCC progression. Novel therapeutic approaches, such as immunotherapy and EGFR inhibitors, have been used to target these dysregulations, and have shown promise in treating advanced cSCC cases, emphasizing the need for targeted interventions considering both genetic and microenvironmental factors for improved patient outcomes.

Changes in T lymphocyte subsets in peripheral blood of patients with middle-advanced cervical cancer before and after nimotuzumab combined with concurrent chemoradiotherapy

The current study sought to investigate the effect of nimotuzumab combined with concurrent chemoradiotherapy (CCRT + Nim) on T lymphocyte subsets in middle-advanced CC. Firstly, patients with middle-advanced CC were administered CCRT or CCRT + Nim. Next, levels of T lymphocytes in peripheral blood of CC patients pre- or post-treatment and healthy females were determined by flow cytometry. The short-term efficacy was evaluated, and overall survival (OS) and progression-free survival (PFS) of patients were recorded. In addition, the correlation of T lymphocyte subsets post-treatment with OS/PFS was assessed with Pearson analysis. CC patients exhibited decreased total T cells/T helper cells/CD4⁺/CD8⁺ ratio and increased T suppressor cells/Tregs in peripheral blood. Meanwhile, CCRT and CCRT + Nim improved T lymphocyte subset imbalance, with CCRT + Nim exhibiting better efficacy. CCRT + Nim exhibited better short-term efficacy and higher PFS than CCRT, with no evident difference in OS. The levels of total T cells/T helper cells/T suppressor cells/Tregs were not significantly-correlated with OS/PFS, and the CD4⁺/CD8⁺ ratio was correlated with PFS but not OS. Collectively, CCRT + nimotuzumab ameliorate the imbalance of T lymphocyte subsets in peripheral blood of middle-advanced CC patients, and the CD4⁺/CD8⁺ ratio after therapy is correlated with PFS.IMPACT STATEMENTWhat is already known on this subject? The utilisation of Nimotuzumab targeting epidermal growth factor receptor (EGFR) combined with concurrent chemoradiotherapy (CCRT) as an efficient treatment for middle-advanced cervical cancer (CC) has garnered the attention of numerous researchers over the years. T cells represent a major immune cell type in the tumour microenvironment and serve as the basis for maintaining cellular immune functions.What do the results of this study add? Our findings revealed that nimotuzumab combined with CCRT improves the abnormality of T lymphocyte subsets in peripheral blood of patients with middle-advanced CC, such that the CD4⁺/CD8⁺ ratio after treatment was significantly correlated with progression-free survival (PFS).What are the implications of these findings for clinical practice and/or further research? CCRT of CC may have a short-term negative impact on the peripheral T-cell immune micro-environment, and the combination of nimotuzumab, cisplatin-based chemotherapy, and radiotherapy enhances the frequency of Tregs in peripheral blood. Our findings illustrated that nimotuzumab combined with CCRT can improve the imbalance of T lymphocyte subsets in peripheral blood of patients with middle-advanced CC. A better understanding of the mechanisms of these therapies will optimise the selection of patients most likely to benefit from treatment, serving as a reference for further research on the relationship between EGFR-specific T cells and clinical benefit in patients treated with nimotuzumab in combination with CCRT.

Interactions of EGFR/PTEN/mTOR-Pathway Activation and Estrogen Receptor Expression in Cervical Cancer

(1) Objective: Late-line chemotherapy rechallenge in recurrent cervical cancer is associated with modest therapy response but significant side effects. As mTOR pathways modulate cellular growth via estrogen receptor (ER) signaling and combined mTOR and ER inhibition previously demonstrated survival benefits in breast cancer, this exploratory study evaluates mTOR pathway and ER expression interactions in a preclinical cervical cancer model. (2) Methods: Immunostaining of a 126-tumor core tissue microarray was performed to assess phosphorylated-mTOR and ER expression. To identify tumor subsets with different clinical behavior, expression results were matched with clinicopathologic patient characteristics, and both univariate and multivariable survival statistics were performed. (3) Results: phosphorylated-mTOR correlates with ER (r = 0.309, p < 0.001) and loss of PTEN expression (r = -2.09, p = 0.022) in tumor samples across stages but not in matched negative controls. Positive ER expression is observed significantly more often in phosphorylated-mTOR positive samples (30.0% vs. 6.3%, p = 0.001). In the subgroup of phosphorylated-mTOR positive tumors (n = 60), ER expression is associated with improved survival (p = 0.040). (4) Conclusion: ER expression appears closely intertwined with EGFR/PTEN/mTOR-pathway activation and seems to define a subgroup with clinically distinct behavior. Considering limited therapeutic options in recurrent cervical cancer, further validation of combined mTOR and ER inhibition in selected patients could appear promising.

Molecular mechanisms augmenting resistance to current therapies in clinics among cervical cancer patients

Cervical cancer (CC) is the fourth leading cause of cancer death (~ 324,000 deaths annually) among women internationally, with 85% of these deaths reported in developing regions, particularly sub-Saharan Africa and Southeast Asia. Human papillomavirus (HPV) is considered the major driver of CC, and with the availability of the prophylactic vaccine, HPV-associated CC is expected to be eliminated soon. However, female patients with advanced-stage cervical cancer demonstrated a high recurrence rate (50-70%) within two years of completing radiochemotherapy. Currently, 90% of failures in chemotherapy are during the invasion and metastasis of cancers related to drug resistance. Although molecular target therapies have shown promising results in the lab, they have had little success in patients due to the tumor heterogeneity fueling resistance to these therapies and bypass the targeted signaling pathway. The last two decades have seen the emergence of immunotherapy, especially immune checkpoint blockade (ICB) therapies, as an effective treatment against metastatic tumors. Unfortunately, only a small subgroup of patients (< 20%) have benefited from this approach, reflecting disease heterogeneity and manifestation with primary or acquired resistance over time. Thus, understanding the mechanisms driving drug resistance in CC could significantly improve the quality of medical care for cancer patients and steer them to accurate, individualized treatment. The rise of artificial intelligence and machine learning has also been a pivotal factor in cancer drug discovery. With the advancement in such technology, cervical cancer screening and diagnosis are expected to become easier. This review will systematically discuss the different tumor-intrinsic and extrinsic mechanisms CC cells to adapt to resist current treatments and scheme novel strategies to overcome cancer drug resistance.

UBE2C Drives Human Cervical Cancer Progression and Is Positively Modulated by mTOR

Cervical cancer is a common gynecological malignancy, accounting for 10% of all gynecological cancers. Recently, targeted therapy for cervical cancer has shown unprecedented advantages. Several studies have shown that ubiquitin conjugating enzyme E2 (UBE2C) is highly expressed in a series of tumors, and participates in the progression of these tumors. However, the possible impact of UBE2C on the progression of cervical squamous cell carcinoma (CESC) remains unclear. Here, we carried out tissue microarray analysis of paraffin-embedded tissues from 294 cervical cancer patients with FIGO/TNM cancer staging records. The results indicated that UBE2C was highly expressed in human CESC tissues and its expression was related to the clinical characteristics of CESC patients. Overexpression and knockdown of UBE2C enhanced and reduced cervical cancer cell proliferation, respectively, in vitro. Furthermore, in vivo experiments showed that UBE2C regulated the expression and activity of the mTOR/PI3K/AKT pathway. In summary, we confirmed that UBE2C is involved in the process of CESC and that UBE2C may represent a molecular target for CESC treatment.

Discovery of 3-(benzofuran-2-ylmethyl)-1H-indole derivatives as potential autophagy inducers in cervical cancer cells

In this manuscript we have documented the identification of a novel anticancer scaffold 3-(benzofuran-2-ylmethyl)-1H-indole. This scaffold has been designed by tweaking the known bisindolylmethane scaffold of natural products that display a wide range of biological activities. A series of 24 new conjugates have been synthesized and among them 5 derivatives exhibited IC₅₀ values less than 40 µM against two cervical cancer cell lines SiHa and C33a. Further mechanistic studies of two compounds 3eb and 3ec revealed that the toxicity of these compounds was due to the effective induction of autophagy mediated cell death. The autophagy induction was confirmed by the progressive conversion of LC3I to LC3II and downregulation of p62 in cervical cancer cells.

PIK3CA Mutations and Their Impact on Survival Outcomes of Patients with Cervical Cancer: A Systematic Review

INTRODUCTION

Several studies have implicated the PIK3/AKT pathway in the pathophysiology of cancer progression as its activation seems to be aberrant in several forms of cancer. The purpose of the present systematic review is to evaluate the impact of PIK3CA mutations on survival outcomes of patients with cervical cancer.

METHODS

We used the Medline (1966-2020), Scopus (2004-2020), ClinicalTrials.gov (2008-2020), EMBASE (1980-2020), Cochrane Central Register of Controlled Trials (CENTRAL) (1999-2020), and Google Scholar (2004-2020) databases in our primary search along with the reference lists of electronically retrieved full-text papers. Statistical meta-analysis was performed with the RevMan 5.3 software.

RESULTS

Overall, 12 articles were included in the present study that comprised 2,196 women with cervical cancer. Of those, 3 studies did not report significant differences in survival outcomes among patients with mutated versus wild-type PIK3CA tumors, 5 studies reported decreased survival outcomes, and 3 studies revealed increased survival rates. The meta-analysis revealed that patients with the mutated PIK3CA genotypes had worse overall survival compared to patients with wild-type PIK3CA (HR 2.31; 95% CI: 1.51, 3.55; 95% PI: 0.54, 9.96; data from 3 studies) and the same was observed in the case of DFS rates (HR 1.82; 95% CI: 1.47, 2.25; 95% PI: 1.29, 2.56; data from 4 studies).

CONCLUSION

Current evidence concerning the impact of PIK3CA mutations on survival outcomes of patients with cervical cancer is inconclusive, although the majority of included studies support a potential negative effect, primarily among those with squamous cell carcinoma tumors.

Vulvar Squamous Cell Carcinoma: Comprehensive Genomic Profiling of HPV+ Versus HPV- Forms Reveals Distinct Sets of Potentially Actionable Molecular Targets

PURPOSE

Vulvar squamous cell carcinoma (vSCC) encompasses two predominant variants: one associated with detectable high-risk strains of human papillomavirus (hrHPV) and a second form often occurring in the context of chronic dermatitis in postmenopausal women. Genomic assessment of a large-scale cohort of patients with aggressive vSCC may identify distinct mutational signatures.

MATERIALS AND METHODS

Tumor samples from a total of 280 patients with vSCC underwent hybridization capture with analysis of up to 406 cancer-related genes. Human papillomavirus (HPV) sequences were detected by de novo assembly of nonhuman sequencing reads and aligned to the RefSeq database. Immunohistochemistry for programmed death-ligand 1 (PD-L1) was assessed.

RESULTS

One hundred two of 280 vSCCs (36%) contained hrHPV sequences, predominantly HPV 16 (88%). The HPV-positive (HPV+) group was significantly younger (median age, 59 v 64 years; P = .001). Compared with HPV-negative (HPV–) vSCCs, HPV+ tumors showed more frequent pathogenic alterations in PIK3CA (31% v 16%; P = .004), PTEN (14% v 2%; P < .0001), EP300 (14% v 1%; P < .0001), STK11 (14% v 1%; P < .0001), AR (5% v 0%; P = .006), and FBXW7 (10% v 3%; P = .03). In contrast, HPV– vSCCs showed more alterations in TP53 (83% v 6%; P < .0001), TERTp (71% v 9%; P < .0001), CDKN2A (55% v 2%; P < .0001), CCND1 amplification (22% v 2%; P < .0001), FAT1 (25% v 4%; P < .0001), NOTCH1 (19% v 6%; P = .002), and EGFR amplification (11% v 0%; P < .0001), as well as a higher rate of 9p24.1 (PDL1/PDL2) amplification (5% v 1%) and PD-L1 immunohistochemistry high-positive tumor staining (33% v 9%; P = .04).

CONCLUSION

Comprehensive molecular profiles of vSCC vary considerably with hrHPV status and may inform patient selection into clinical trials. Sixty-one percent of HPV+ vSCCs had a pathogenic alteration in the PI3K/mTOR pathway, whereas HPV– vSCCs showed alterations in TP53, TERTp, CDKN2A, CCND1, and EGFR, and biomarkers associated with responsiveness to immunotherapy.

Abemaciclib sensitizes HPV-negative cervical cancer to chemotherapy via specifically suppressing CDK4/6-Rb-E2F and mTOR pathways

Cervical cancer is the second most common malignancy in women, and the novel therapeutic treatment is needed. Abemaciclib is a FDA-approved drug for breast cancer treatment. In this work, we identified that abemaciclib has potent anti-cervical cancer activity. We demonstrate that abemaciclib is the most effective drug against human papillomavirus (HPV)-negative cervical cancer cells compared to ribociclib and palbociclib, with its IC₅₀ at nanomolar concentration range. This is achieved by the inhibition of proliferation and induction of apoptosis, through specifically suppressing CDK4/6-Rb-E2F and mTOR pathways by abemaciclib in HPV-negative cervical cancer cells. Of note, the combination of abemaciclib with paclitaxel and cisplatin at sublethal concentration results in much greater efficacy than chemotherapy alone. In addition, we confirm the efficacy of abemaciclib and its combination with paclitaxel or cisplatin at the doses that are not toxic to mice in HPV-negative cervical cancer xenograft mouse model. Interestingly, we show that abemaciclib and other CDK4/6 inhibitors are not effective in targeting HPV-positive cervical cancer cells, and this is likely to be associated with the high p16 and low Rb expression in HPV-positive cervical cancer cells. Our work is the first to provide the preclinical evidence to demonstrate the potential of abemaciclib for the treatment of HPV-negative cervical cancer. The mechanism analysis highlights the therapeutic value of inhibiting CDK4/6 in HPV-negative but not HPV-positive cervical cancer.

circRNA MYLK Accelerates Cervical Cancer via Up-Regulation of RHEB and Activation of mTOR Signaling

Background

Growing evidence directly suggested that circular RNAs (circRNAs) are crucial contributors in the course of cervical cancer (CC) onset and progression. Nevertheless, a large number of circRNAs have not been fully addressed in their function and underlying mechanisms during CC etiology.

Purpose

Our study focused on the function of circRNA MYLK (myosin light chain kinase), one novel tumor-related circRNA, in CC cell behaviors.

Methods

Firstly, we evaluated the expression profile of circMYLK in CC cells and in normal Ect1/E6E7 cell line. Moreover, the accurate function of circMYLK in CC cells was assessed via colony formation, CCK-8, EdU, and TUNEL assay. The association among circRNAs, miRNA, and target mRNAs was predicated by bioinformatics methods and validated in mechanical assays.

Results

We disclosed that circMYLK was up-regulated in CC cell lines and acted as a sponge of miR-1301-3p. Besides, downstream miR-1301-3p was capable of reversing circMYLK-mediated CC cell growth and apoptosis. Furthermore, we validated that circMYLK bound to miR-1301-3p as a sponge to upregulate RHEB (Ras homolog, mTORC1 binding) expression. As annotated in prior works, RHEB was responsible for mTOR signaling transduction. Therefore, we investigated whether circMYLK functioned its tumor-facilitating impact in CC through a RHEB-dependent mTOR signaling activation.

Conclusion

It was unveiled that circMYLK sponged miR-1301-3p to promote RHEB expression, which resulted in mTOR signaling activation and CC cell malignant growth.

Clinical study of nimotuzumab combined with concurrent radiochemotherapy for treatment of locally advanced cervical cancer

PURPOSE

Nimotuzumab is a humanized monoclonal antibody that targets the epidermal growth factor receptor (EGFR) to inhibit tumor growth. Nimotuzumab has demonstrated desirable therapeutic activity in various types of tumors. However, the benefit of nimotuzumab for the treatment of cervical cancer is not entirely clear. The present study aimed to investigate the effects of nimotuzumab in the presence of CCRT in the first-line treatment of locally advanced cervical cancer (LACC).

METHODS

The therapeutic efficacy and side effects of nimotuzumab combined with concurrent radiochemotherapy (CCRT) were retrospectively assessed in inoperable patients with LACC (stage IIb-IIIb) who were treated using CCRT with or without nimotuzumab.

RESULTS

The complete response rate of study group was significantly better than control group (78.3% vs 50%, P=0.035). The difference in median progression-free survival (PFS) in the two groups was statistically significan (not reach vs 27 months, P=0.037). Multivariate comparisons of prognostic factors in the two groups indicated that both the Fédération Internationale de Gynécologie et d'Obstétrique (FIGO) stage and combined nimotuzumab treatment affected PFS (P<0.05). Although generally tolerable, grade 3-4 toxicities including leukopenia (P=0.025) and hemoglobin (P=0.026) reduction were more frequent in the control group than those in the study group.

CONCLUSION

These data suggest that combining nimotuzumab with CCRT for the treatment of LACC resulted in extended PFS and higher complete remission rates, without an increased incidence of adverse events.

The Next Generation Scientist program: capacity-building for future scientific leaders in low- and middle-income countries

BACKGROUND

Scientific and professional development opportunities for early career scientists in low- and middle- income countries (LMICs) are limited and not consistent. There is a disproportionately low number of biomedical and clinical researchers in LMIC's relative to their high burden of disease, a disparity that is aggravated by emigration of up to 70% of scientists from their countries of birth for education and employment elsewhere. To help address this need, a novel University-accredited, immersive fellowship program was established by a large public-academic-private network. We sought to describe the program and summarize progress and lessons learned over its first 7-years.

METHODS

Hallmarks of the program are a structured learning curriculum and bespoke research activities tailored to the needs of each fellow. Research projects expose the scientists to state-of-the-art methodologies and leading experts in their fields while also ensuring that learnings are implementable within their home infrastructure. Fellows run seminars on drug discovery and development that reinforce themes of scientific leadership and teamwork together with practical modules on addressing healthcare challenges within their local systems. Industry mentors achieve mutual learning to better understand healthcare needs in traditionally underserved settings. We evaluated the impact of the program through an online survey of participants and by assessing research output.

RESULTS

More than 140 scientists and clinicians from 25 countries participated over the 7-year period. Evaluation revealed strong evidence of knowledge and skills transfer, and beneficial self-reported impact on fellow's research output and career trajectories. Examples of program impact included completion of post-graduate qualifications; establishment and implementation of good laboratory- and clinical- practice mechanisms; and becoming lead investigators in local programs. There was a high retention of fellows in their home countries (> 75%) and an enduring professional network among the fellows and their mentors.

CONCLUSIONS

Our experience demonstrates an example for how multi-sectoral partners can contribute to scientific and professional development of researchers in LMICs and supports the idea that capacity-building efforts should be tailored to the specific needs of beneficiaries to be maximally effective. Lessons learned may be applied to the design and conduct of other programs to strengthen science ecosystems in LMICs.

Streptomyces sp metabolite(s) promotes Bax mediated intrinsic apoptosis and autophagy involving inhibition of mTOR pathway in cervical cancer cell lines

In cervical cancer, the association between HPV infection and dysregulation of phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway (PI3K/AKT/mTOR pathway) places mTOR as an attractive therapeutic target. The failure of current treatment modalities in advanced stages of this cancer and drawbacks of already available mTOR inhibitors demand for novel drug candidates. In the present study we identified the presence of a mTOR inhibitor in an active fraction of the ethyl acetate extract of Streptomyces sp OA293. The metabolites(s) in the active fraction completely inhibited mTORC1 and thereby suppressed activation of both of its downstream targets, 4E-BP1 and P70S6k, in cervical cancer cells. In addition, it also stalled Akt activation via inhibition of mTORC2. The mechanism of mTOR inhibition detailed in our study overcomes significant drawbacks of well known mTOR inhibitors such as rapamycin and rapalogs. The active fraction induced autophagy and Bax mediated apoptosis suggesting that mTOR inhibition resulted in programmed cell death of cancer cells. The molecular weight determination of the components in active fraction confirmed the absence of any previously known natural mTOR inhibitor. This is the first report of complete mTOR complex inhibition by a product derived from microbial source.